Treatment instrument

Abstract

The present invention is a treatment instrument comprising: an inner fixation instrument that is inserted into a vertebral body from a pedicle; and an outer tube, wherein the treatment instrument is configured as follows. The inner fixation instrument has: a head part having a first connection part connectable to the outer tube; and a shaft extending from the head part to a proximal end, wherein the shaft is provided with a tapping screw thread which is tapped and screwed into a bone hole formed in the pedicle. The outer tube has a second connection part connectable to the first connection part of the inner fixation instrument, wherein a connection state between the second connection part and the first connection part is maintained with respect to rotation in a direction opposite to a direction in which the inner fixation instrument is screwed by the tapping screw thread. As a result, it is possible to provide a treatment instrument with which the inner fixation instrument embedded in the body during vertebroplasty can be easily removed even if it becomes necessary to remove the inner fixation instrument in the future. In addition, in vertebroplasty, it is possible to stabilize a procedure for filling bone cement into the vertebral body from the pedicle and inserting the inner fixation instrument thereinto.

Description

treatment equipment

[0001] The present invention relates to a medical device, and is particularly suitable for use in surgery in which cement is filled inside the affected bone and a screw is screwed into the cement from the outside of the bone.

[0002] Vertebroplasty and spinal fusion are known treatments for spinal compression fractures. The spine consists of stacked vertebral bodies, the vertebral arches that support and connect them vertically, the pedicles, and the upper and lower articular processes. The vertebral bodies are cylindrical bones that sandwich the nucleus pulposus and the surrounding annulus fibrosus from above and below, and are supported by two pedicles extending from the vertebral arches. The vertebral arches are connected vertically by the upper and lower articular processes, and support the vertebral bodies via the pedicles, forming the spine. Compression fractures are diseases in which the vertebral bodies are crushed and damaged by vertical compression.

[0003] Vertebroplasty is a surgical procedure to reconstruct a collapsed vertebral body, for example, by filling the vertebral body with artificial bone or medical cement (referred to herein as "bone cement" or simply "cement"). Vertebroplasty is performed through a small percutaneous incision, minimizing invasiveness and reducing the burden on the patient, thereby contributing to a reduction in hospital stays and ultimately medical and nursing care costs. While percutaneous vertebroplasty has shown good results in many cases, there have also been reported complications, such as instability of the filled cement, resulting in dislocation, and insufficient improvement of the vertebral body and intervertebral instability, requiring additional surgery. To prevent these complications, a method has been proposed in which screws are inserted through the pedicle into the cement mass after filling and before hardening to internally fixate (reconstruct) the fractured vertebrae (a procedure combining vertebroplasty and pedicle plasty) (Yoshiaki Yonezawa et al., "Percutaneous vertebroplasty for osteoporotic vertebral pseudarthrosis: Combined use of PMMA and intravertebral screws," Fracture Research Paper, Vol. 28, pp. 444-448, 2006, Japanese Society for the Treatment of Fractures). This technique has been successfully applied to many patients. This technique may also be effective not only for vertebroplasty for compression fractures, but also for spinal fusion for osteoporotic degenerative spinal disease and spinal reinforcement in lumbar artificial disc replacement.

[0004] Spinal fusion is a surgical procedure for fixing the affected intervertebral space in cases of degenerative spinal disease, and for compression fractures, it is a surgical procedure for fixing the healthy vertebrae above and below using spinal fusion implants. In spinal fusion, screws are inserted into the pedicles of multiple vertebrae, and the heads of the screws are connected to rods that run vertically between each other to fix the affected intervertebral space or fractured vertebra. Depending on the condition of the affected vertebra, spinal fusion, artificial disc replacement, or vertebroplasty are selected or combined for each disease.

[0005] Various medical devices have been proposed for use in these treatments.

[0006] Patent Document 1 discloses a screwdriver for driving a screw from a pedicle to a vertebral body. The screwdriver is composed of a shank for rotating the pedicle screw, a clamping sleeve that supports the shank so that it can rotate around the shank, and an adapter sleeve that is attached to the clamping sleeve and transmits rotation from the handle. The adapter sleeve is detachable, and when removed, the shank and clamping sleeve remain connected to the pedicle screw, thereby improving the surgeon's view of the surgical area (paragraphs 0014 and 0015).

[0007] Patent Document 2 discloses a medical screw that can be easily removed from a fracture site after being screwed in. This medical screw is hollow from the head along the central axis, has a threaded portion on the outside, and has a reverse internal threaded portion that runs in the opposite direction to the threaded portion near the inner hollow tip. When screwing in this medical screw, a hex wrench (Figure 3) that engages with the hexagonal groove on the head is used, and when removing it, a removal tool (Figure 6) is used, which has a reverse external threaded portion at the tip that engages with the reverse internal thread.

[0008] Patent Documents 3 and 4 disclose a treatment instrument including a cylindrical driver capable of driving a screw into bone and an inner tube that can be inserted into the driver. The screw, driver, and inner tube are integrated and inserted into the vertebral body through the pedicle. A balloon catheter and a cement filling tube are sequentially inserted in place of the inner tube to fill the bone cement, and the screw can be screwed into the filled bone cement mass by operating the driver. The head of the screw has a hexagonal groove that fits and connects with, for example, a hexagonal wrench at the tip of the driver. If it becomes necessary to remove the screw from the bone cement mass in the future, the tip of the driver is connected to the head of the screw, and the screw can be rotated and removed.

[0009] JP 2016-19728 A JP 2016-209295 A Japanese Patent No. 7300133 A Japanese Patent No. 7329895 A

[0010] The screwdriver disclosed in Patent Document 1 also functions as a cement injection cannula, and is capable of injecting cement into a pedicle screw via the shank without changing the instrument (paragraphs 0058 to 0068). However, as the document states, "immediately after the pedicle screw is screwed, cement can be injected into the pedicle screw 30 into which the cannula is inserted via the shank 2 without changing the instrument" (paragraph 0068), it is not intended to screw a screw into a cement mass after cement injection. Therefore, it is obvious that the document does not consider removing a screw screwed into a cement mass.

[0011] The treatment instruments shown in Patent Documents 3 and 4 integrate a screw, driver, and inner cylinder, and insert the screw into the vertebral body through the pedicle. The inner cylinder is then removed and a cavity is formed in the vertebral body using a balloon catheter. The cavity is then filled with bone cement using a cement filling tube, and the screw is then screwed into the filled bone cement using the driver. If it becomes necessary to remove the screw in the future, the driver can be fitted into the screw head again and the screw can be rotated and removed.

[0012] The present inventor, an orthopedic surgeon, noticed that the hollow structure of the treatment instruments shown in Patent Documents 3 and 4 lacked a stable guide function when passing a balloon catheter or cement-filled tube through the through-hole of the screw or driver. Because the tip of the driver simply fits into the head of the screw, the connection was unstable. For example, there was a risk of the screw and driver becoming detached during the procedure of inserting and removing the balloon catheter into the through-hole. If the driver became detached from the screw due to insufficient stability as a guide, there was a risk of requiring an extra step of blindly reconnecting the screw within the muscle. Furthermore, there was a risk that the driver would strip the hexagonal groove in the screw head when removing the screw.

[0013] The medical instrument disclosed in Patent Document 2 is a removal tool for screw removal. The screw at the tip of the removal tool is threaded onto a thread located deep within the hollow portion of the screw, and the tool is rotated to remove the screw, making the risk of stripping the screw unlikely. However, this removal tool is used solely for screw removal and does not function as a guide to guide other instruments through the pedicle to inject bone cement into the vertebral body. An insertion hole 13d is provided in the center, but this is provided for inserting a removal guide pin. The removal tool is guided by the screw along this guide pin, and the insertion hole in the removal tool does not guide the guide pin.

[0014] An object of the present invention is to provide a treatment instrument that stabilizes the procedure of filling bone cement into the vertebral body from the pedicle and inserting an internal fixation device therein during vertebroplasty, and that also facilitates the removal of the internal fixation device if it becomes necessary in the future.

[0015] The inventor will mainly explain below how to simultaneously solve both the problems of insufficient stability as a guide and the difficulty of separating the screw from the bone cement by using the interaction of a series of instruments, but the present application also includes a means for solving only one of the problems. Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

[0016] According to one embodiment of the present invention, the following is true.

[0017] That is, the treatment device includes an internal fixation device that is inserted into the vertebral body from the pedicle and an outer cylinder, and is configured as follows.

[0018] The internal fixation device has a head having a first connecting portion connectable to the outer cylinder, a shaft extending from the head to a proximal end, a through hole penetrating the central axis of the shaft, and a tapping screw thread that is tapped and screwed into a bone hole formed in the pedicle.

[0019] The outer cylinder has a second connecting portion that can be connected to the first connecting portion of the internal fixation device.

[0020] The connected state between the second connecting portion and the first connecting portion is maintained against rotation in the direction opposite to the direction in which the internal fixation device is screwed in by the tapping screw threads.

[0021] Here, the term "internal fixation device" refers to a device that is inserted from the pedicle side into bone cement filled inside the vertebral body to fix the bone cement. It refers to a device that includes the above-mentioned screw, and includes devices in which the self-tapping thread does not extend to the proximal side of the shaft. "Proximal" is a medical term referring to the side closer to the centerline of the patient's body, and "distal" refers to the farther side. The term "cement" refers to a medical bone cement, for example, whose main components are calcium phosphate and polymethylmethacrylate, and which hardens over time.

[0022] The effects obtained by the embodiment are briefly described below.

[0023] In other words, it is possible to provide a therapeutic instrument that stabilizes the procedure of filling bone cement into the vertebral body from the pedicle and inserting an internal fixation device into it during vertebroplasty, and that also facilitates the removal of the internal fixation device if it becomes necessary in the future.More particularly, the therapeutic instrument of the present invention has both a guide function for guiding an instrument for inserting an internal fixation device into the vertebral body and a function for removing the internal fixation device, without using a screwdriver that has been required for removal in the past or a dedicated removal tool such as that disclosed in Patent Document 2.

[0024] FIG. 1 is an explanatory diagram schematically showing cross-sectional structures to illustrate configuration examples of the treatment instruments of Embodiments 1 to 3. FIG. 2 is a cross-sectional view schematically showing one configuration example of the internal fixation instrument. FIG. 3 is a front view of the internal fixation instrument of FIG. 2. FIG. 4 is a cross-sectional view schematically showing another configuration example of the internal fixation instrument. FIG. 5 is a front view of the internal fixation instrument of FIG. 4. FIG. 6 is a cross-sectional view schematically showing an example of the configuration of an inclined portion of the shaft of the internal fixation instrument. FIG. 7 is a cross-sectional view schematically showing one configuration example of a connection portion between the internal fixation instrument and an outer tube. FIG. 8 is a cross-sectional view schematically showing another configuration example of a connection portion between the internal fixation instrument and an outer tube. FIG. 9 is an explanatory diagram schematically showing cross-sectional structures to illustrate the treatment instrument of Embodiment 4. FIG. 10A is a cross-sectional view schematically showing an example of a connection structure (connected state) between an outer tube, a driver, and a bone drilling inner tube. FIG. 10B is a cross-sectional view schematically showing a state before the driver is connected to the outer tube in the configuration example of the connection structure. FIG. 10C is a cross-sectional view schematically showing a state after the driver has been connected to the outer tube in the configuration example of the connection structure. FIG. 10D is a cross-sectional view schematically showing a state in which the outer tube and the driver are connected and the outer tube has been detached from the internal fixation device in the configuration example of the connection structure. FIG. 10E is a cross-sectional view schematically showing a configuration example in which the connection structure of Embodiment 5 is applied to the driver with the bone-drilling inner tube of Embodiment 6. FIG. 10F is a cross-sectional view schematically showing a configuration example in which the connection structure of Embodiment 5 is applied to the cement molding instrument of Embodiment 9. FIG. 11 is an explanatory view schematically showing a cross-sectional structure to show an example of the configuration of the treatment instrument of Embodiment 6. FIG. 12 is a partial front view schematically showing one example of the configuration of a driver integrated with a bone-drilling inner tube. FIG. 13 is a partial front view schematically showing another example of the configuration of a driver integrated with a bone-drilling inner tube. FIG. 14 is an explanatory view schematically showing a cross-sectional structure to show the treatment instrument of Embodiment 7. FIG. 15 is an explanatory view schematically showing an example of the configuration of the treatment instrument of Embodiment 8. Fig. 16 is an explanatory diagram showing a configuration example of a cement pushing rod and a cement fixing device. Fig. 17 is an explanatory diagram showing a configuration example of a treatment device of embodiment 9. Fig. 18 is an explanatory diagram showing a configuration example of a cement molding device and a cement fixing device. Fig. 19 is an explanatory diagram showing a schematic cross-sectional structure to show one configuration example of an internal fixation device cap.FIG. 20 is an explanatory diagram schematically illustrating a cross-sectional structure to show another configuration example of the internal fixation device cap. FIG. 21 is an explanatory diagram (first half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 3. FIG. 22 is an explanatory diagram (second half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 3. FIG. 23 is an explanatory diagram illustrating the procedure of a surgical procedure for removing an internal fixation device using the treatment device of embodiment 3. FIG. 24 is an explanatory diagram (first half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 6. FIG. 25 is an explanatory diagram (second half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 6. FIG. 26 is an explanatory diagram illustrating the procedure of a surgical procedure for removing an internal fixation device using the treatment device of embodiment 6. FIG. 27 is an explanatory diagram (first half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 7. FIG. 28 is an explanatory diagram (second half) illustrating the procedure of a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 7. FIG. 29 is an explanatory diagram showing the procedure of a surgical procedure for removing an internal fixation device using the treatment instrument of embodiment 7. FIG. 30 is an explanatory diagram schematically showing the cross-sectional structure of the treatment instrument of embodiment 11. FIG. 31 is an explanatory diagram showing an example of the operation of the cement separating instrument. FIG. 32 is an enlarged view showing an example of the configuration of the tip portion of the cement separating instrument. FIG. 33 is an enlarged view showing another example of the configuration of the tip portion of the cement separating instrument. FIG. 34 is an explanatory diagram showing an example of the procedure of a surgical procedure for removing an internal fixation device using the treatment instrument of embodiment 11. FIG. 35 is an explanatory diagram showing another example of the procedure of a surgical procedure for removing an internal fixation device using the treatment instrument of embodiment 11. FIG. 36 is an explanatory diagram schematically showing the cross-sectional structure of the treatment instrument of embodiment 12. FIG. 37 is an explanatory diagram showing an example of the configuration of a cap. FIG. 38 is an explanatory diagram showing another example of the configuration of a cap. FIG. 39 is a cross-sectional view showing an example of the configuration of a connecting portion of an improved driver with the internal fixation device and the cap. FIG. 40 is an explanatory diagram showing the procedure of a surgical procedure for removing an internal fixation device using the treatment instrument of embodiment 12. Fig. 41 is an explanatory diagram showing an example of the configuration of the tip portions of the cement molding instrument and the cement separating instrument. Fig. 42 is an explanatory diagram schematically showing the cross-sectional structure of the treatment instrument of embodiment 14.Fig. 43 is an explanatory diagram showing an example of the procedure for a surgical procedure for removing an internal fixation device using the treatment device of embodiment 14. Fig. 44 is an explanatory diagram (first half) showing the procedure for a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 9. Fig. 45 is an explanatory diagram (middle half) showing the procedure for a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 9. Fig. 46 is an explanatory diagram (last half) showing the procedure for a surgical procedure for implanting an internal fixation device using the treatment device of embodiment 9.

[0025] 1. Overview of the Embodiments First, an overview of the representative embodiments disclosed in the present application will be described. Reference numerals in parentheses in the drawings used in the overview of the representative embodiments merely illustrate components included in the concept of the components to which they are attached.

[0026] [1] A therapeutic device for facilitating removal of an internal fixation device implanted by vertebroplasty (Fig. 1) A representative embodiment disclosed in the present application is a therapeutic device (10) including an internal fixation device (1) inserted into a vertebral body from a pedicle and an outer tube (2), and is configured as follows.

[0027] The internal fixation device has a head (11) having a first connecting portion (12) connectable to the outer cylinder, a shaft (14) extending from the head to a proximal end, a first through-hole (19) passing through the central axis of the shaft, and a tapping screw thread (15) formed on the shaft. The tapping screw thread formed on the shaft is tapped and screwed into a bone hole formed in the pedicle.

[0028] The outer cylinder has a second connecting portion (21) connectable to the first connecting portion of the internal fixation device. The connected state between the second connecting portion and the first connecting portion is maintained against rotation in the direction opposite to the direction in which the internal fixation device is screwed in by the tapping screw thread.

[0029] This makes it possible to provide a therapeutic instrument that stabilizes the procedure of filling bone cement into the vertebral body from the pedicle and inserting an internal fixation device into it during vertebroplasty, and also makes it easy to remove the internal fixation device if it becomes necessary in the future. The therapeutic instrument in [1] has both a guide function for guiding an instrument for inserting an internal fixation device and a function for removing the internal fixation device, without using a screwdriver that has been required for removal in the past or a dedicated removal tool such as that disclosed in Patent Document 2.

[0030] [2] Connection between the internal fixation device and the outer tube: A thread structure in the opposite direction to the tapping thread of the internal fixation device (Fig. 7). In the treatment device of [1], the first connecting part and the second connecting part are connected to each other by a thread in the opposite direction to the tapping thread.

[0031] This allows the outer tube to be connected to the internal fixation device so that it will not loosen even if rotated when removing the internal fixation device. Because the outer tube is connected to the internal fixation device by rotating in the same direction as the internal fixation device is screwed into the pedicle, during vertebroplasty procedures, including the procedure of screwing the internal fixation device into the pedicle, the outer tube connected to the internal fixation device functions as a guide to guide other instruments into the vertebral body, and the connection is oriented in a way that prevents loosening due to this operation, thereby stabilizing the procedure. Furthermore, during vertebroplasty procedures in which bone cement is filled into the vertebral body through the pedicle and the internal fixation device is inserted therein, even when the outer tube is removed from the internal fixation device after implanting the internal fixation device, the direction of rotation of the outer tube is the same as the direction of rotation when the internal fixation device is screwed into the pedicle. This eliminates the risk of the internal fixation device rotating together with the outer tube due to the connection between the first connecting portion of the internal fixation device and the second connecting portion of the outer tube being too strong, resulting in loosening of the screwing into the pedicle and even removal.

[0032] [3] Connection between the internal fixation device and the outer tube: L-shaped groove (Fig. 8) In the treatment device of [1], the second connecting portion has a protrusion (211). The first connecting portion has a longitudinal groove (121) through which the protrusion passes when the outer tube is advanced along the central axis toward the internal fixation device to connect with the first connecting portion, and a transverse groove (122) into which the protrusion fits when the outer tube is rotated around the central axis in a direction opposite to the direction in which the tapping screw thread is screwed in when the protrusion reaches the proximal end of the longitudinal groove, thereby restricting further rotation in the opposite direction and release of the connection along the central axis.

[0033] As a result, similar to [2], the outer tube is connected to the internal fixation device so that it will not loosen even if it is rotated when removing the internal fixation device. The outer tube is linearly advanced in the central axial direction of the internal fixation device, with the convex portion thereof extending to the end of the vertical groove, and then rotated to advance it into the horizontal groove. Because the rotation direction is opposite to the direction in which the tapping screw threads of the internal fixation device are screwed in, the connection between the outer tube and the internal fixation device will not be released by the action of rotating the outer tube to rotate and remove the internal fixation device. Furthermore, since the connection between the outer tube and the internal fixation device will not be released by a linear force, the connection remains stable even when removing the internal fixation device without rotating the internal fixation device, for example, by destroying the thread grooves of the weakened pedicle bone tunnel.

[0034] [4] The connected internal fixation device and outer tube function as a guide to guide a driver or the like into the vertebral body (Figs. 1, 9, 10A-10E, 11). The treatment device according to any one of [1] to [3] further includes a driver (3).

[0035] The through hole is a first through hole (19), the internal fixation device has a first fitting portion (13) at the head, and the outer cylinder has a second through hole (29) that passes through the central axis and through which the driver can be passed.

[0036] The driver has a second fitting portion (33) that fits with the first fitting portion of the internal fixation device when inserted into the second through-hole.

[0037] This stabilizes the procedure of filling bone cement into the vertebral body from the pedicle and inserting an internal fixation device into it during vertebroplasty, because the outer tube is stably connected to the internal fixation device during vertebroplasty, which involves implanting the internal fixation device, and can function as a guide to guide a screwdriver or the like into the vertebral body.

[0038] [5] Connection mechanism that allows the driver and outer tube to be attached and detached by movement along the central axis (Figs. 10A to 10F) In the treatment instrument of [4], the driver is connected to the outer tube when engaged with the engaging portion of the internal fixation device, and is equipped with a connection mechanism (300) that can be attached and detached by moving the driver along the central axis within the second through-hole.

[0039] This allows for smooth attachment and detachment, and the connection integrates the driver, outer cylinder, and internal fixation device, allowing for screwing in or removal operations while stably supporting the internal fixation device.

[0040] [6] Specific examples of connection mechanisms between a driver and an outer tube (Figs. 10A to 10F) In the treatment instrument of [5], the connection mechanism is configured to include a convex portion (e.g., latch convex portion 201) provided on the outer tube in a direction away from the central axis and an elastic body (e.g., latch protrusion 301 and leaf spring 302) provided on the driver, and is configured so that the elastic body can bend and pass through the convex portion due to the force that moves the driver along the central axis within the second through hole.

[0041] This prevents the driver from easily falling off when connected to the outer cylinder, but allows it to be easily removed by applying force, achieving smooth attachment and detachment.

[0042] [7] Specific example of a connection mechanism between a driver and an outer tube (Fig. 10D) In ​​the treatment instrument of [5], the connection mechanism is configured so that the connection between the second connection part and the first connection part can be released when the driver and the outer tube are connected.

[0043] This allows the outer cylinder and driver to be removed from the internal fixation device while still connected.

[0044] [8] The outer cylinder can be rotated with a wrench (Figs. 10A to 10F, 30, 32, 34, 40). In the treatment instrument according to any one of [5] to [7], the outer cylinder has a wrench fitting portion on its outer periphery.

[0045] This allows a wrench to be connected when a large force is required to remove the internal fixation device.The wrench only needs to be connected when necessary, so if it is not needed, such as when functioning as a guide to guide an instrument for inserting the fixation device, the wrench is not attached, and a fixed handle is provided so that it does not interfere with the guide function.

[0046] [9] Bone-Drilling Inner Tube (Inserted from the Through-Hole of the Driver) (Figs. 1, 9, 10A-10D) The treatment instrument according to any one of [4] to [8] further includes a bone-drilling inner tube (4). The driver has a third through-hole (39) along its central axis, and the bone-drilling inner tube is inserted through the communicating through-hole when the internal fixation device, the outer tube, and the driver are connected to one another, and has a bone-drilling portion (41) protruding from the tip of the internal fixation device. The driver is detachably connected to the distal end of the outer tube when fitted into the fitting portion of the internal fixation device, and is detachably connected to the bone-drilling inner tube at its distal end when the bone-drilling inner tube is inserted.

[0047] This integrates the bone drilling inner tube, driver, and outer tube, allowing for a stable procedure for forming a bone hole in the pedicle, while allowing the bone drilling inner tube to be removed in other procedures to allow for the insertion of other instruments such as guide pins.

[0048]

[10] The bone drilling inner tube is connected to the driver with a screw structure (Figs. 10A to 10D). In the treatment instrument of [9], the bone drilling inner tube is connected to the driver with a screw thread in the same direction as the tapping screw thread of the internal fixation device.

[0049] This reduces the risk of inadvertently loosening the internal fixation device when connecting the bone drilling inner cylinder.

[0050]

[11] Guide pin through hole in bone drilling inner tube (Figs. 9, 10A-10D) In ​​the treatment instrument of [9] or

[10] , the bone drilling inner tube has a fourth through hole (49) that penetrates from the distal end to the tip.

[0051] This allows the treatment instrument of the present invention to be inserted into the pedicle along the guide pin.

[0052]

[12] Driver with Bone Drilling Inner Cylinder (Figs. 11 to 13) In the treatment instrument of any one of [4] to [8], the driver further has a bone drilling inner cylinder (4) extending proximally from the tip of the fitting portion. The bone drilling inner cylinder has a bone drilling portion (41) that protrudes from the tip through the first through-hole of the internal fixation device when the driver is fitted into the fitting portion of the internal fixation device.

[0053] This allows the internal fixation device to be introduced into the vertebral body from the pedicle while forming a bone hole in the pedicle using a driver with a bone-drilling inner barrel, thereby simplifying the procedure.

[0054]

[13] Tapping screw at the tip of bone drilling inner tube (Fig. 13) In the treatment instrument of

[12] , if the tapping screw thread (15) of the internal fixation device is called the first tapping screw thread, the bone drilling portion at the tip of the bone drilling inner tube (4) of the driver has a second tapping screw thread (42) on the outer periphery, which is different from the first tapping screw thread. The second tapping screw thread is formed so as to follow the same path as the first tapping screw thread when the driver is fitted into the fitting portion of the internal fixation device.

[0055] This allows a bone hole to be easily formed in the pedicle using a driver with a bone-boring inner tube, and an internal fixation instrument to be smoothly inserted into the formed bone hole.

[0056]

[14] A driver with a bone-drilling inner tube having a through hole for a guide pin (Fig. 14) In the treatment instrument of

[12] or

[13] , the driver has a third through hole (39) that passes from the distal end to the tip of the bone-drilling inner tube.

[0057] This allows the treatment instrument of the present invention to be inserted into the pedicle along the guide pin.

[0058] [Additional Problems to be Solved by the Invention] Further problems to be solved by the present invention will be described below.

[0059] The present inventor, an orthopedic surgeon, has noticed a new problem in addition to the problem described above in "Problems to be Solved by the Invention." That is, he has noticed that, in the treatment instruments shown in Patent Documents 3 and 4, when separating a screw from bone cement fixed to the tip of the screw and removing the screw from the bone cement inside the bone, it is not possible to apply sufficient force to the screw and bone cement in the direction of separation.

[0060] The need for screw removal may arise early after surgery, such as when interference with spinal nerves is identified early after surgery, or it may occur several weeks to months after surgery, such as when deep infection develops at the fracture site. Furthermore, when removing a screw integrated with bone cement, the screw must be removed from the posterior and the bone cement from the anterior and lateral sides of the vertebral body, respectively, to avoid damaging vital organs (spinal nerves, nerve roots, large vessels anterior to the vertebral body, and remaining bone such as intact pedicles and vertebral arches). In some circumstances, screw and bone cement removal may be necessary, even if they are firmly attached to the bone cement. However, this may result in internal loosening. Because the bone cement and screw are strongly bonded once integrated, attempting to remove the screw from the posterior may result in the internal bone cement rotating along with the screw, making removal impossible. Attempting forceful removal poses a risk to the surrounding area. Thus, there is a risk that the screw and bone cement may not be able to be separated and removed.

[0061] Even with the screwdriver shown in Patent Document 1, if the cement mass that has adhered to the tip of the screw becomes loose from the surrounding bone, even if you try to rotate only the screw to remove it from the insertion trajectory, it is not possible to separate the cement mass from the screw, and the screw and bone cement mass will rotate together while remaining integrated, creating a situation where you have no choice but to forcibly remove the screw backwards, destroying the normal vertebrae. This is an extremely dangerous operation that can damage the spinal nerves and nerve roots, which are nearby important organs.

[0062]

[15] Cement Separation Instrument (Figs. 30 to 38, 43) In the treatment instrument according to any one of [1] to [3], the treatment instrument further includes a cement separation instrument (800).

[0063] The treatment instrument is equipped with a motion direction conversion mechanism that converts the rotational force of the cement separation instrument, which is inserted into a through hole that communicates when the internal fixation instrument and the outer tube are connected to each other, and which rotates around the central axis of the first through hole into a linear force that moves the cement separation instrument straight along the central axis, with the internal fixation instrument or the outer tube connected to the internal fixation instrument as a fulcrum.

[0064] This makes it possible to provide a treatment instrument that stabilizes the procedure in vertebroplasty, in which bone cement is filled into the vertebral body from the pedicle and an internal fixation device is inserted therein, and also makes it easy to remove the internal fixation device if it becomes necessary in the future.In particular, it is possible to apply a linear pushing force to the bone cement using the internal fixation device or an outer tube connected to it as a fulcrum to separate it from the internal fixation device.

[0065]

[16] Fixing portion at the tip of the cement separating instrument (Fig. 36) In the treatment instrument of

[15] , the cement separating instrument has a tip portion that protrudes from the tip of the internal fixation instrument when the cement separating instrument is inserted into a through hole that communicates when the internal fixation instrument, the outer tube, and the driver are connected to each other.

[0066] This makes it even easier to remove the internal fixation device. After filling the bone cement and inserting the internal fixation device, the tip of the cement separation device can be fitted into the hole formed in the bone cement when removing the internal fixation device, which prevents the bone cement from rotating within the vertebral body and facilitates the operation of rotating and removing the internal fixation device.

[0067]

[17] The outer cylinder can be rotated with a wrench (Figs. 10A to 10E, 30, 32, 34, 40). In the treatment instrument of

[15] or

[16] , the outer cylinder has a wrench fitting portion on its outer periphery.

[0068] This allows a wrench to be connected when a large force is required to prevent the internal fixation device from rotating while rotating the cement separation device. The wrench can be removed when not needed and does not interfere with other operations.

[0069]

[18] Cement Filling Tube, Cement Pusher Rod, and Cement Fixation Device (Figs. 15 and 16) In any one of [4] to

[17] , the treatment device further includes a cement filling tube (5), a cement pushing rod (6), and a cement fixation device (8). The driver has a third through-hole (39). The cement filling tube has a first grip (51) at its distal end and is inserted into a through-hole that communicates when the internal fixation device, the outer tube, and the driver are connected to each other. The cement pushing rod is inserted along the central axis of the cement filling tube and has a cement molding portion (62) that protrudes from the tip of the internal fixation device. The cement fixation device is inserted into a through-hole that communicates when the internal fixation device and the outer tube are connected to each other and protrudes from the tip of the internal fixation device, and its tip (cement fixation portion 82) is inserted into a hole formed in the bone cement in the vertebral body by the cement molding portion.

[0070] This makes it even easier to remove the internal fixation device. After filling the bone cement and inserting the internal fixation device, the tip of the cement fixation device can be fitted into the hole formed in the bone cement when removing the internal fixation device, which prevents the bone cement from rotating within the vertebral body and facilitates the operation of rotating and removing the internal fixation device.

[0071]

[19] Cement molding instrument and cement fixation instrument (Figs. 17 and 18) In any one of [3] to

[17] , the treatment instrument further includes a cement molding instrument (7) and a cement fixation instrument (8). The cement molding instrument has a cement molding part (72) that protrudes from its tip through a through-hole that communicates when the internal fixation instrument, the outer cylinder, and the driver are connected to each other. The cement fixation instrument protrudes from its tip through a through-hole that communicates when the internal fixation instrument, the outer cylinder, and the driver are connected to each other, and its tip (cement fixation part 82) is inserted into a hole formed in the bone cement in the vertebral body by the cement molding part.

[0072] This makes it even easier to remove the internal fixation device. After filling the hole with bone cement and inserting the internal fixation device, the tip of the cement fixation device can be fitted into the hole formed using the cement molding device when removing the internal fixation device, which prevents the bone cement from rotating within the vertebral body and facilitates the operation of rotating and removing the internal fixation device.

[0073] [15-1] Details of the cement separation instrument: Motion direction conversion mechanism on the outer cylinder (Fig. 30) The treatment instrument of

[15] or

[16] has a third shaft (804) that is inserted into a through hole that communicates when the internal fixation instrument, the outer cylinder, and the driver of the cement separation instrument are connected to one another. The third shaft has a separation instrument side screw thread (802) on its outer periphery, and the motion direction conversion mechanism is formed by the engagement of the outer cylinder side screw thread (22) formed in the second through hole of the outer cylinder and the separation instrument side screw thread of the third shaft of the cement separation instrument.

[0074] This allows the rotational force of the internal fixation device, which rotates around the central axis thereof, to be converted into a linear force that moves the cement separating device linearly along the central axis thereof, with the outer cylinder as a fulcrum. Although not shown in the drawings, even if the through-hole of the internal fixation device is clogged with bone cement, bone fragments, scars, or other foreign matter, the cement separating device can be penetrated by drilling or otherwise removing the foreign matter from the through-hole of the internal fixation device in advance, and the internal fixation device can be safely separated from the bone cement and removed.

[0075] [15-2] Details of the cement separation instrument; movement direction change mechanism in the internal fixation instrument (Fig. 32) In the treatment instrument of

[15] or

[16] , the third shaft of the cement separation instrument has a separation instrument side thread (802) on its outer periphery, and the movement direction change mechanism is formed by the internal fixation instrument side thread (18) provided in the first through hole of the internal fixation instrument and the separation instrument side thread engaging with each other.

[0076] This allows the fulcrum of the linear force that moves the separation instrument straight to be located inside the internal fixation instrument, and the internal fixation instrument can be separated and removed from the bone cement more safely.

[0077] [15-3] Cap for cement separation device (Figs. 33 and 34) In the treatment device of any one of

[15] ,

[16] , [15-1] to [15-2], the treatment device further includes a cap (9). The cap is inserted into the opening in the head of the internal fixation device.

[0078] This prevents the head of the internal fixation device from becoming blocked by bone cement, bone fragments, scar tissue, or other foreign matter.

[0079] [18, 19-1] Details of the cement-fixed device: tapping threads on the outer periphery (Figs. 16, 18) In the treatment device of

[18] or

[19] , the cement-molding part is cylindrical, or a cylindrical tapered or conical shape whose diameter decreases toward the tip, and the cement-fixed device has a tapping thread that fits into the hole formed by the cement-molding part.

[0080] This allows the cement fixation device to be screwed into the hole formed by the cement pushing rod or the cement molding portion at the tip of the cement molding device, more firmly preventing the bone cement from rotating, making it easier to remove the internal fixation device.

[0081] [18, 19-2] The cement molding part and the cement fixing device are fitted with a screw thread (Figs. 16, 18). In the treatment device of

[18] or

[19] , the cement molding part is cylindrical, or a cylindrical tapered or conical shape whose diameter decreases toward the tip, and has a formed screw thread on its outer periphery that forms a screw groove in the hole molded in the bone cement, and the cement fixing device has a screw thread that fits with the screw groove formed by the formed screw thread of the cement molding part.

[0082] This allows the cement fixation device to fit into the thread groove formed by the cement molding portion at the tip of the cement pushing rod or cement molding device, more firmly preventing the rotation of the bone cement and making it easier to remove the internal fixation device.

[0083]

[20] Internal fixation device cap (Figs. 19, 20) In any one of [3] to

[19] , the treatment device further includes a cap (9), which is inserted into the opening in the head of the internal fixation device.

[0084] This prevents the head of the internal fixation device from becoming blocked by adhesion to surrounding body tissues, such as scars, after the internal fixation device has been implanted in the patient's body and before it becomes necessary to remove it, thereby preventing the device from being removed.

[0085]

[21] Fixing the internal fixation device cap to the internal fixation device (Fig. 20) In the treatment device of

[20] , the cap has a fixing portion (e.g., a screw thread 74) that is inserted into the first through hole of the internal fixation device and protrudes from the tip.

[0086] As a result, the cap is fixed to the cement filled in the vertebral body by the fixing portion protruding from the tip of the internal fixation instrument.

[0087]

[22] Fixing the internal fixation device cap to a molded screw groove (Fig. 20) In the treatment device of

[21] , the fixing portion of the cap has a screw thread (74) on its outer periphery.

[0088] This allows the cap to be firmly fixed to the cement filled in the vertebral body. For example, the cap can be fixed by screwing the fixing portion (thread 74) at the tip of the cap into a screw groove (73) formed in the cement at the tip of the internal fixation instrument.

[0089]

[23] Detailed specifications of the internal fixation device (inclined portion) (Figs. 2 to 6) In the treatment device of any one of [1] to

[19] , the internal fixation device has a blunt tip and an inclined portion (16) that tapers toward the proximal side of the shaft.

[0090] This weakens the strength of the fixation of the internal fixation device to the bone cement mass, helps separate the internal fixation device from the bone cement mass, and makes it easier to remove the internal fixation device.In addition, in the procedure of introducing a balloon catheter into the vertebral body and inflating the balloon to form a cavity (space) before filling the vertebral body with bone cement, it is possible to reduce the risk of damaging the balloon with the tip of the internal fixation device and also to weaken the resistance to removal from the bone cement.

[0091]

[24] Detailed specifications of the internal fixation device (multi-stage inclined portion) (Fig. 6) In the treatment device of

[23] , the inclined portion includes first and second inclined portions having successively different inclination angles toward the proximal side of the shaft.

[0092] This allows the strength of the internal fixation device to be adjusted by changing the thickness thereof, making it even easier to remove the internal fixation device.

[0093]

[25] Detailed specifications of the internal fixation device (screw groove / thread on the outer periphery) (Fig. 3) In the treatment device of

[23] or

[24] , the inclined portion has a spiral groove (17) or thread on the outer periphery.

[0094] This allows the strength of fixation of the internal fixation device to be adjusted by taking into consideration the balance between the risk of dislodging the bone cement mass and the strength of removal.

[0095]

[26] Detailed specifications of the internal fixation device (island-shaped grooves / ridges on the outer periphery) (illustration omitted) In the treatment device of

[23] or

[24] , the inclined portion has a recess or a protrusion on the outer periphery.

[0096] This allows the strength of fixation of the internal fixation device to be adjusted by taking into consideration the balance between the risk of dislodging the bone cement mass and the strength of removal.

[0097] 2. Details of the embodiment The embodiment will be described in further detail.

[0098] First Embodiment FIG. 1 is an explanatory diagram that schematically shows a cross-sectional structure to illustrate a configuration example of a treatment device 10 according to a first embodiment.

[0099] The treatment instrument 10 includes an internal fixation instrument 1 that is inserted into the vertebral body from the pedicle, and an outer cylinder 2. Also shown in Figure 1 is a driver 3 and a bone-drilling inner cylinder 4, which will be described later.

[0100] The internal fixation device 1 has a head 11 having a first connecting portion 12 connectable to the outer cylinder 2, a shaft 14 extending from the head 11 to the proximal end, a first through-hole 19 passing through the central axis of the shaft 14, and a tapping screw thread 15 on the distal side of the shaft 14. The internal fixation device 1 is screwed into a bone hole formed in the pedicle by tapping with the tapping screw thread 15.

[0101] The outer tube 2 has a second connecting portion 21 connectable to the first connecting portion 12 of the internal fixation device 1. The connected state between this second connecting portion 21 and the first connecting portion 12 of the internal fixation device 1 is maintained even when the internal fixation device 1 is rotated in the direction opposite to the direction in which it is screwed in by the self-tapping screw threads 15. "Maintaining the connected state" means that the connection is not released. When removing the internal fixation device 1, the internal fixation device 1 is rotated in the direction opposite to the direction in which it was screwed in while connected to the outer tube 2. This prevents the connection between the internal fixation device 1 and the outer tube 2 from loosening or coming off. This provides a treatment device that allows for easy removal of the internal fixation device 1 implanted in a body during vertebroplasty, even if it becomes necessary to do so in the future. In other words, this treatment device 10 combines a guide function for guiding an instrument for inserting the internal fixation device into a vertebral body and a function for removing the internal fixation device, without using a screwdriver or a dedicated removal tool such as that disclosed in Patent Document 2, which have been conventionally required for removal.

[0102] The connection mode between the connecting portion 12 of the internal fixation device 1 and the connecting portion 21 of the outer tube 2 may be any as long as the connection is not released by rotation in the direction opposite to the direction in which the internal fixation device 1 is screwed in by the self-tapping threads 15 when removed, i.e., by rotation in the opposite direction to the direction in which the internal fixation device 1 is screwed in by the self-tapping threads 15. For example, the first connecting portion 12 and the second connecting portion 21 may be connected to each other by threads in the opposite direction to the self-tapping threads 15 formed on the outer periphery of the internal fixation device 1. When the internal fixation device 1 is screwed in by rotating it clockwise by the self-tapping threads 15, the first connecting portion 12 and the second connecting portion 21 are connected by a counterclockwise thread. This connection will not loosen or come off with the same counterclockwise rotation force, so the connection is stably maintained when the self-tapping threads 15 of the internal fixation device 1 are turned counterclockwise to remove it from the bone tunnel.

[0103] This structure is effective not only when removing the internal fixation device during the vertebroplasty procedure, but also when filling bone cement into the vertebral body from the pedicle and inserting the internal fixation device 1. When removing the outer tube from the internal fixation device after implanting the internal fixation device, the direction of rotation of the outer tube is the same as the direction of rotation when screwing the internal fixation device into the pedicle, eliminating the risk that the connection between the first and second connecting parts is too strong and the internal fixation device rotates together with the outer tube, causing it to loosen and even come out of the pedicle.

[0104] The first connecting portion 12 and the second connecting portion 21 may be simply referred to as "connecting portion 12" and "connecting portion 21," and may also be referred to as "connecting portions 12 and 21" when there is no particular need to distinguish between them. The first through hole 19, the second through hole 29, and the third through hole 39 and fourth through hole 49 described below may also be simply referred to as "through hole 19," "through hole 29," "through hole 39," and "through hole 49." The first fitting portion 13 and the second fitting portion 33 may also be simply referred to as "fitting portion 13" and "fitting portion 33."

[0105] [Embodiment 2] The treatment instrument 10 of the present invention may further include a driver 3. The internal fixation device 1 has a first fitting portion 13 in the head 11. The outer cylinder 2 has a second through-hole 29 that penetrates the central axis and allows the driver 3 to pass through. The driver 3 has a second fitting portion 33 that fits with the first fitting portion 13 of the internal fixation device 1 when inserted into the second through-hole 29. The second fitting portion 33 may be, for example, a hexagonal prism in the shape of a hexagonal wrench, and the first fitting portion 13 may be a hexagonal groove into which the second fitting portion 33 fits, although the shapes may be changed as appropriate.

[0106] This stabilizes the procedure of filling bone cement into the vertebral body through the pedicle and inserting the internal fixation device 1 into it during vertebroplasty. During vertebroplasty, in which the internal fixation device 1 is implanted, the outer tube 2 is connected to the internal fixation device 1 and functions as a guide for guiding the driver 3 and other instruments into the vertebral body. That is, the internal fixation device 1 and the outer tube 2 of the present invention are connected to each other, and the first through-hole 19 and the second through-hole 29 communicate with each other, functioning as a guide for sequentially guiding the driver 3, as well as a bone drilling instrument, a balloon catheter, a cement filling tube, and other instruments, into the vertebral body, as will be described later. Furthermore, while the internal fixation device 1 and the outer tube 2 are connected, the driver 3 can be inserted through the second through-hole 29, and the fitting portion 33 can be fitted into the fitting portion 13 of the head 11 of the internal fixation device 1 and rotated, thereby screwing the internal fixation device 1 into the bone cement filled in the vertebral body. At this time, the tapping screw threads 15 formed on the distal side of the shaft of the internal fixation device 1 tap the bone hole in the pedicle while pushing the internal fixation device 1 deeper, and the shaft 14 portion on the proximal side of the internal fixation device 1 is pressed into the bone cement. In this way, the procedure can be carried out by simply sequentially replacing the inserted instruments while the internal fixation device 1 and the outer tube 2 remain connected, which simplifies the procedure.

[0107] As explained in the first embodiment, if it becomes necessary to remove the internal fixation device 1 in the future, even if the fitting portion 13 of the head 11 does not fit properly with the fitting portion 33 at the tip of the driver 3 and the internal fixation device 1 cannot be rotated and removed with the driver 3, the connection portion between the internal fixation device 1 and the outer cylinder 2 is in the opposite direction to the tapping thread 15, so that when the outer cylinder 2 is rotated in the opposite direction, the tapping thread 15 follows the groove formed by tapping in the bone hole in the pedicle, providing a force to pull out the internal fixation device 1, thereby allowing the internal fixation device 1 to be removed. In this way, the treatment device 10 of the present invention can also function as a guide to guide the driver 3 and the like into the vertebral body while maintaining the effect of facilitating the removal of the internal fixation device 1.

[0108] In this way, a treatment instrument can be provided that stabilizes the procedure in vertebroplasty, in which bone cement is filled into the vertebral body from the pedicle and an internal fixation device is inserted therein, and also makes it easy to remove the internal fixation device if it becomes necessary in the future.

[0109] [Embodiment 3] The treatment instrument 10 preferably further includes a bone drilling inner cylinder 4. The driver 3 has a third through-hole 39 through which the bone drilling inner cylinder 4 can pass. The third through-hole 39 communicates with the through-hole 19 of the internal fixation instrument 1 when the driver 3 is inserted into the through-hole 29 of the outer cylinder 2. The bone drilling inner cylinder 4 has a bone drilling portion 41 at its tip that can drill a pedicle or vertebral body. The bone drilling portion 41 is configured to protrude from the tip of the internal fixation instrument 1 when the driver 3 is inserted into the through-holes 29 and 19 that communicate with each other and the internal fixation instrument 1 and the outer cylinder 2 are connected to each other at the connecting portions 12 and 21, and the bone drilling inner cylinder 4 is inserted into the through-hole 39 of the driver 3. It is preferable that the driver 3 be detachably connected to the distal end of the outer tube 2 when the fitting portion 33 is fitted into the fitting portion 13 of the internal fixation device 1, and that when the bone drilling inner tube 4 is inserted, the driver 3 be detachably connected to the bone drilling inner tube 4 at the distal end.

[0110] This integrates the bone drilling inner tube 4, the driver 3, and the outer tube 2, allowing the procedure of forming a bone hole in the pedicle to be performed stably, while in other procedures the bone drilling inner tube 4 can be removed and other instruments such as a guide pin can be inserted through the through hole 19 communicating with the through hole 39 of the driver 3, or through the through hole 19 communicating with the through hole 29 of the outer tube 2 after the driver 3 has been removed.

[0111] The method of connecting the internal fixation device 1, outer cylinder 2, and driver 3 is arbitrary as long as it satisfies the above requirements, but may be configured as follows, for example: The tapping screw thread 15 on the outer periphery of the internal fixation device 1 is formed in a direction in which the internal fixation device 1 is screwed into a bone hole formed in the pedicle 91 by turning it clockwise. The connection parts 12 and 21 of the internal fixation device 1 and outer cylinder 2 are detachably connected by a thread structure in which they are connected by turning them counterclockwise, and detached by turning them clockwise.

[0112] [Procedure] An example of a procedure for surgery using the treatment instrument 10 of the present invention will be described.

[0113] Figures 21 and 22 are explanatory diagrams showing the procedure for the surgical procedure to implant the internal fixation device 1. Figure 21 shows the first half, and Figure 22 shows the second half. Figure 23 is an explanatory diagram showing the procedure for the surgical procedure to remove the internal fixation device 1. Each figure shows a schematic cross section of a path from the skin 90 on the back of a patient to a vertebral body 92 via a pedicle 91. In an actual surgery, a single vertebral body 92 is approached from both the left and right pedicles 91 using the same procedure, but Figures 21 to 23 show only one side schematically, and the length ratios in both the vertical and horizontal directions have been changed as appropriate for explanation. The same applies to Figures 24 to 29, 34 to 35, 40, 43 to 46, etc., which will be described later.

[0114] An example of a procedure for implanting the internal fixation device 1 into the body will be described below. Steps 1 to 3 are preparatory steps.

[0115] Step 1: Connect the outer tube 2 to the internal fixation device 1. The second connecting portion 21 at the tip of the outer tube 2 is connected to the first connecting portion 12 at the head of the internal fixation device 1 by screwing it in counterclockwise.

[0116] Step 2: The bone drilling inner cylinder 4 is inserted into the through-hole 39 of the driver 3 and connected at the distal end to form an integrated unit. The connection at the distal end is not particularly limited, but may be a latch structure that can be attached and detached by operating a lever, as shown in Figures 10A to 10F. Furthermore, if a handle is formed at the distal end, it is suitable for drilling bone and rotating the internal fixation device 1.

[0117] Step 3: Insert and connect the integrated bone drilling inner cylinder 4 and driver 3 into the connected internal fixation device 1 and outer cylinder 2. For this connection, a connection mechanism such as a latch structure that can be attached and detached by operating a lever may be provided at the distal ends of the outer cylinder 2 and driver 3. This results in a treatment device 10 in which the internal fixation device 1, outer cylinder 2, bone drilling inner cylinder 4, and driver 3 are integrated.

[0118] Step 4 ([1] in Figure 21): The treatment instrument 10 integrated in steps 1 to 3 is inserted directly into the incised skin. The treatment instrument 10 is inserted while being checked with an intraoperative X-ray, and is advanced until the tip touches the bone (vertebral arch).

[0119] Step 5 ([2]): When the position where the tip of the treatment instrument 10 abuts is appropriate, the proximal side of the internal fixation instrument 1 is advanced into the pedicle 91 by striking the head of the bone drilling inner tube 4 or the integrated driver 3 with a hammer, or by screwing in the entire treatment instrument 10, until the tip reaches the entrance of the vertebral body 92.

[0120] Step 6 ([3]): The bone drilling inner cylinder 4 is removed from the treatment instrument 10. The internal fixation instrument 1 and the outer cylinder 2 and driver 3 connected thereto remain.

[0121] Step 7 ([4]): A bone excavation tool 25 is inserted into the through-hole (third through-hole 39) of the driver 3 of the treatment instrument 10 from which the bone drilling inner cylinder 4 has been removed, and excavates the inside of the vertebral body 92. The bone excavation tool 25 may be a straight excavation tool such as a drill, or may be an instrument with a bent tip that can excavate the surrounding area.

[0122] Step 8 ([5]): A balloon catheter 26 is inserted through the through hole 39 of the driver 3 instead of the bone drilling tool 25, and the balloon 27 is inflated within the vertebral body 92 to restore the vertebral body to its original state due to the compression fracture and form a cavity.

[0123] Step 9 ([6]): The balloon 27 is de-inflated and the balloon catheter 26 is pulled out from the through-hole of the driver 3, leaving a cavity 28 in the vertebral body 92.

[0124] Step 10 ([7] in Figure 22): The cement filling tube 5 is inserted through the through-hole 39 of the driver 3, and the bone cement previously filled in the cement filling tube 5 is injected using the cement pushing rod 6. A suitable amount of bone cement can be filled by preparing multiple cement filling tubes 5 pre-filled with bone cement and filling each of the left and right pedicles three to four times. Instead of the cement filling device consisting of the cement filling tube 5 and the cement pushing rod 6, a cement filling device may be used in which a syringe is connected to the cement filling tube 5 via a tube, and the cement filled in the syringe is pushed out to fill the cavity.

[0125] Step 11 ([8]): After removing the cement filling tube 5 and cement pushing rod 6, the driver 3 is rotated to screw the internal fixation device 1 into the pedicle 91 and bone cement 50. The internal fixation device 1 has a tapping screw thread 15 formed on its outer periphery, so it advances and fixes itself into the bone hole formed in the pedicle 91 while tapping. The bone cement 50 that has filled the cavity 28 in the vertebral body 92 and formed a mass has not yet hardened at this point, and the proximal side of the internal fixation device 1 is inserted into the bone cement 50.

[0126] Step 12 ([9]): The cement molding instrument 7 is inserted into the bone cement 50 through the through-hole 39 of the driver 3. A hole is formed in the bone cement 50 at the end of the through-hole 19 of the internal fixation device 1 with the cement molding instrument 7, and the bone cement 50 is molded into a predetermined shape. It is more preferable that the distal side of the cement molding instrument 7, on the part exposed from the through-hole 39 of the driver 3, be provided with a scale or a mark indicating the appropriate insertion depth.

[0127] Step 13 (

[10] ): The cement molding instrument 7 is removed. A hole having a desired shape is formed in the bone cement 50 at the bottom of the through-hole 19 of the internal fixation instrument 1 by the tip of the cement molding instrument 7. The depth of the hole formed in the bone cement 50 can be adjusted to an appropriate depth, for example, about 1 cm from the tip of the internal fixation instrument 1.

[0128] Step 14 (

[11] ): After removing the driver 3 and the outer tube 2, the wound is closed (the incision is closed by suturing). The outer tube 2 is removed by rotating it clockwise to loosen the connecting parts 12 and 21. [11'] in Figure 21 will be described later.

[0129] Steps 12 and 13 ([9] and

[10] ) of inserting the cement molding tool 7 to form and mold a hole for fixing the bone cement 50 may be omitted.

[0130] As described above, in the treatment instrument 10 of the present invention, the internal fixation instrument 1 and the outer cylinder 2 are connected to each other, and the through-hole 19 and the through-hole 29 communicate with each other (in this example, the through-hole 39 of the driver 3 also communicates with the through-hole 19 of the internal fixation instrument 1), and they function as guides for sequentially introducing the bone drilling inner cylinder 4, the balloon catheter 26, and the cement filling tube 5 into the vertebral body 92 (steps 7, 8, and 10, [4] and [5] of FIG. 21, and [7] of FIG. 22). Furthermore, while the internal fixation instrument 1 and the outer cylinder 2 are connected, the driver 3 is inserted through the through-hole 29 of the outer cylinder 2, fitted into the head of the internal fixation instrument 1, and rotated (step 11, [8] of FIG. 22), whereby the internal fixation instrument 1 can be screwed into the bone cement 50 filled in the vertebral body. At this time, the tapping screw threads 15 formed on the distal side of the internal fixation device 1 tap the bone hole in the pedicle 91, while pushing the shaft portion on the proximal side of the internal fixation device 1 into the bone cement 50. In this way, the procedure can be carried out by simply sequentially replacing the inserted devices while the internal fixation device 1 and the outer tube 2 remain connected, which simplifies the procedure.

[0131] An example of a procedure for removing the internal fixation device 1 will be described with reference to FIG.

[0132] Step 1 ([1]): The skin is incised to expose the head 11 of the internal fixation device 1 through the wound incision 93.

[0133] Step 2 ([2]): Connect the outer tube 2 to the head 11 of the internal fixation device 1. At this time, the tapping screw thread 15 on the outer periphery of the internal fixation device 1 is screwed clockwise into the pedicle 91 and fixed, and the connecting portions 12 and 21 have threads formed in the opposite direction, so turn the outer tube 2 counterclockwise to connect it to the head 11 of the internal fixation device 1.

[0134] Step 3 ([3]): Insert the screwdriver 3 into the through hole (the through hole where the through holes 19 and 29 are connected) formed by connecting the internal fixation device 1 and the outer tube 2, and fit its tip into the fitting portion 13 of the head 11 of the internal fixation device 1. For example, the tip of the screwdriver 3 is a hexagonal column shaped like a hexagonal wrench, and the fitting portion 13 is a groove that fits into the hexagonal wrench, and is configured to fit simply by inserting the screwdriver 3.

[0135] Step 4 ([4]): The cement-fixing instrument 8 is inserted into the through-holes (through-holes 39 and 19 communicating with each other) of the driver 3 and the internal fixation instrument 1, and its tip is fitted into the hole formed into a predetermined shape by the cement-molding instrument 7 in step 12 ([9] in FIG. 22) of the procedure for inserting the internal fixation instrument 1 described above. The shapes of the tip portions of the cement-molding instrument 7 and the cement-fixing instrument 8 will be described in detail later, but the tip portion of the cement-fixing instrument 8 fits into the hole formed by the cement-molding instrument 7, preventing the bone cement 50 from rotating.

[0136] Step 5 ([5]): While holding the bone cement 50 with the cement fixation tool 8, rotate the driver 3 and outer tube 2 counterclockwise to remove the internal fixation tool 1 from the bone cement 50 and the pedicle 91. Because the tapping screw threads 15 on the outer periphery of the internal fixation tool 1 are screwed into the pedicle 91 clockwise as described above, it can be removed by rotating it counterclockwise. At this time, the connection parts 12 and 21 between the driver 3 and outer tube 2 are also rotated counterclockwise, so the connection between the driver 3 and outer tube 2 does not loosen even when this operation is performed.

[0137] Step 6 ([6]): After the tapping screw threads 15 are released from the pedicle 91, the screwed internal fixation device 1 can be pulled out while still connected to the outer tube 2. After the internal fixation device 1 and the driver 3 connected to the outer tube 2 are removed, the wound site 93 is closed. The driver 3 may be pulled out first, and then the internal fixation device 1 connected to the outer tube 2 may be pulled out, or the internal fixation device 1, outer tube 2, and driver 3 may be pulled out while still connected together.

[0138] Steps 4 to 5 ([4] to [5]) show an example assuming the use of the cement-fixed instrument 8, but if the internal fixation instrument 1 is not firmly bonded to the bone cement 50, these steps may be omitted and the internal fixation instrument 1 may be removed from the bone cement 50 simply by turning the screwdriver 3. Furthermore, if the internal fixation instrument 1 is not firmly bonded, step 3 ([3]) may also be omitted and the internal fixation instrument 1 may be removed simply by turning the outer cylinder 2 without using the screwdriver 3.

[0139] As described above, if it becomes necessary in the future to remove the internal fixation device 1 implanted using the procedure described with reference to Figures 21 and 19, for example, if the fitting portion 13 of the head does not fit properly with the tip of the driver 3 and the internal fixation device 1 cannot be rotated and removed using the driver 3, the treatment device 10 of the present invention will enable the internal fixation device 1 to be removed. Because the connection portions 12 and 21 between the internal fixation device 1 and the outer tube 2 are oriented in the opposite direction to the tapping thread 15 of the internal fixation device 1, when the outer tube 2 is rotated in the opposite direction, the tapping thread 15 follows the groove formed by tapping in the bone hole of the pedicle 91, providing a force to remove the internal fixation device 1, facilitating removal of the internal fixation device 1. In this way, the treatment device 10 of the present invention also has the effect of facilitating removal of the internal fixation device 1.

[0140] [Details of the Internal Fixation Device] The internal fixation device 1 constituting the treatment device 10 of the present invention will be described in more detail. The internal fixation device 1 is, for example, a medical screw, and is configured to be inserted from the pedicle into bone cement 50 filled in the vertebral body.

[0141] FIG. 2 is a cross-sectional view showing a schematic configuration example of the internal fixation device 1. The internal fixation device 1 comprises a head 11 and a shaft 14. The head 11 is provided with a connecting portion 12 to which the outer tube 2 is connected and a fitting portion 13 into which the fitting portion 33 of the driver 3 is fitted. The shaft 14 has a self-tapping thread 15 on the distal side (the side closer to the head 11). The self-tapping thread 15 is formed for tapping a bone hole formed in the pedicle to screw the internal fixation device 1 into place. The self-tapping thread 15 does not need to be formed to a position that contacts the head 11; it is sufficient that it engages with at least a portion of the pedicle into which it is screwed. The tip of the internal fixation device 1 is preferably blunted, and the shaft 14 preferably has a tapered portion 16 that tapers toward the proximal side. The procedure for inserting the internal fixation device 1 involves inserting a balloon catheter through the through-hole 19 of the internal fixation device 1, inflating the balloon, and then deflating and withdrawing it. The blunting of the tip of the internal fixation device 1 reduces the risk of damaging the balloon during this step. For example, the degree of blunting can be designed such that, for the tip of the internal fixation device 1 with an inner diameter of 3.7 to 3.9 mm and a wall thickness of 0.15 to 0.25 mm, the inner radius of curvature is 0.075 to 0.10 mm and the outer radius of curvature is 0.075 to 0.10 mm. Furthermore, the inclined portion 16 can reduce the resistance to separation when the internal fixation device 1 is separated from the bone cement.

[0142] FIG. 3 is a front view of the internal fixation device 1 shown in FIG. 2 . The shaft 14 of the internal fixation device 1 or its inclined portion 16 may have a spiral groove 17 formed on the outer periphery. The procedure for inserting the internal fixation device 1 includes a step of inserting the internal fixation device 1 into bone cement 50. At this time, the bone cement 50 has not yet hardened, so it enters the spiral groove 17 when the internal fixation device 1 is screwed in. Even if the internal fixation device 1 is first inserted to its final depth and then the bone cement 50 is filled, the tip of the internal fixation device 1 is covered with the filled bone cement 50, resulting in the same phenomenon. This reduces the risk of the bone cement 50 becoming dislodged. Meanwhile, because the groove 17 is spiral, the internal fixation device 1 can be removed by rotating it along the groove.

[0143] It is more preferable that the spiral groove 17 of the internal fixation device 1 be formed with the same lead as the self-tapping thread 15. This allows the spiral groove 17 of the internal fixation device 1 to be smoothly inserted into the bone cement 50. When the internal fixation device 1 is screwed into (removed from) the bone cement 50, the distance traveled in the rotational and linear directions (depth direction) is determined by the lead of the self-tapping thread 15. Therefore, if the rotational and linear directions are the same, it is advantageous, particularly when removing the internal fixation device 1 after the bone cement 50 has hardened. Specifically, when removing the internal fixation device 1 from the bone cement 50 after the bone cement 50 has hardened, the self-tapping screw 15 on the distal side of the internal fixation device 1 and the spiral groove 17 at the tip have the same lead, so that the rotational force in the removal direction is more fully transmitted, reducing the risk of damaging the bone around the self-tapping thread 15 on the distal side of the internal fixation device 1 and preventing the internal fixation device 1 from spinning freely inside the bone, allowing for more stable removal. The spiral groove 17 of the internal fixation device 1 may be shallow on the proximal side and gradually deepen toward the distal side. This allows the bone cement 50 to more smoothly enter the groove when screwed into the bone cement 50. The number of threads of the spiral groove 17 of the internal fixation device 1 may be smaller than the number of threads of the tapping screw thread 15. By reducing the number of threads of the groove 17, it is possible to adjust the amount of bone cement that enters the groove 17, thereby ensuring an appropriate pull-out strength between the bone cement 50 and the internal fixation device 1 to prevent the internal fixation device 1 from becoming unable to be removed, while minimizing the risk of the internal fixation device 1 being accidentally detached from the bone cement 50 inside the body. The number of threads of the spiral groove 17 can be adjusted taking into consideration prevention of dislodgment and resistance during removal, for example by varying the number of threads on the proximal and distal sides of the shaft 14.

[0144] A concentric groove or an island-shaped recess may be formed at the distal end of the internal fixation device 1 instead of the spiral groove 17. As described above, if the spiral groove 17 is formed with the same lead as the tapping thread 15, the internal fixation device 1 penetrates into the bone cement 50 along the same trajectory as when the tapping thread 15 is screwed into the pedicle while tapping. This allows the bone cement 50 to more smoothly penetrate into the groove 17. However, when the bone cement 50 has not yet hardened and has a low viscosity, the bone cement 50 can penetrate even into a concentric groove or an island-shaped recess. This shape is formed to prevent the bone cement 50 from slipping out, but on the other hand, it also acts to make it difficult to remove the internal fixation device 1. It is recommended that the shape be appropriately designed and selected taking into consideration the trade-off between preventing the bone cement 50 from slipping out and facilitating the removal of the internal fixation device 1. For example, when the internal fixation device 1 can be inserted deeply into the bone cement 50, there is no need to be particularly concerned about preventing dislodgement, so it is sufficient to form shallow spiral grooves 17 or sparsely form island-shaped recesses. On the other hand, when it is expected that the internal fixation device 1 will not be inserted deeply, it is preferable to form deep grooves so that prevention of dislodgement takes priority.

[0145] FIG. 4 is a cross-sectional view schematically illustrating another configuration example of the internal fixation device 1, and FIG. 5 is a front view of the internal fixation device 1 of FIG. 4. The internal fixation device 1 does not have either a tapping thread 15 or a spiral groove 17. The bone hole formed in the pedicle may have a diameter large enough to allow the shaft 14 to pass through but not the head 11. Alternatively, the shaft 14 may be used to widen the bone hole before passing through. When the shaft 14 is inserted into the bone hole formed in the pedicle, the head 11 stops at the entrance of the bone hole, and the inclined portion 16 of the tip of the shaft 14 inserted through the bone hole is inserted into the bone cement 50 filled in the vertebral body. When the bone cement 50 hardens, the inclined portion 16 is fixed, and the hardened bone cement mass and the head 11 of the internal fixation device 1 sandwich both sides of the bone hole in the pedicle, supporting the bone cement 50 from the pedicle side and fixing it in the vertebral body. Unlike the example of FIG. 3, the shaft 14 of the internal fixation device 1 does not have grooves 17 or the like formed therein, and therefore the force of adhesion between the bone cement 50 and the internal fixation device 1 is weaker.

[0146] When the internal fixation device 1 can be inserted deeply into the bone cement 50, the risk of dislodging the bone cement mass is low and the force required for removal can be reduced even if an internal fixation device 1 with weak fixing strength is used as shown in Figures 4 and 5. On the other hand, when the internal fixation device 1 cannot be inserted deeply into the bone cement 50, it becomes more important to prevent dislodging of the bone cement mass, so an internal fixation device 1 having a spiral groove 17 or the like at the tip, such as that shown in Figure 3, can be selected.

[0147] Furthermore, in order to adjust the adhesive strength with the bone cement 50, various configurations can be adopted for the inclined portion 16 of the internal fixation device 1.

[0148] 6 is a cross-sectional view schematically showing an example of the configuration of the inclined portion 16 of the shaft 14 of the internal fixation device. The shaft 14 may be configured to include multiple inclined portions 16 with different inclination angles. For example, the inclination angles may be configured to gradually increase toward the proximal side of the shaft 14. This makes it possible to adjust the thickness of the internal fixation device, maintain its strength, and further facilitate removal of the internal fixation device 1.

[0149] FIG. 6A shows a cross section of the entire internal fixation device 1, and FIGS. 6B to 6D show various modified examples with enlarged views of the proximal side of the shaft 14. L0 indicates the length of the shaft 14 inserted into the bone cement 50 during a typical surgical procedure. L0 is approximately 2 cm. Even with a design where L0 = 2 cm, the insertion depth may be shallower (e.g., 0.5 cm) in some cases. The shaft 14 in FIG. 6B has a long, single-step taper (inclined portion 16). A long, inclined portion with a uniform inclination angle is formed throughout L0. The shaft 14 in FIG. 6C has a short, single-step taper (inclined portion 16) on the proximal side. When L0 = 2 cm, for example, L1 = 0.7 cm. The shaft 14 in FIG. 6D has a proximal inclined portion with a length L1 and a distal inclined portion with a smaller inclination angle L2. The number of taper steps and length can be changed as appropriate.

[0150] The configuration of the inclined portion of the shaft 14 is designed to provide appropriate stability, strength, and ease of insertion and removal, taking into consideration cases such as when the bone cement 50 is not sufficiently filled, or when the bone cement 50 hardens more than expected before the internal fixation device 1 is inserted. In this case, as shown in Fig. 3, the number of spiral grooves 17 formed on the outer periphery of the shaft 14, or whether to use a chevron-shaped or trapezoidal protruding thread instead of the grooves 17, are also considered as important factors that affect the stability, strength, and ease of insertion and removal.

[0151] 7A and 7B are cross-sectional views schematically showing an example of the configuration of the connection portions 12 and 21 of the internal fixation device 1 and the outer tube 2. In the example shown in (A), the connection portion 12 of the internal fixation device 1 is disposed on the outer periphery side, and the connection portion 21 of the outer tube 2 is disposed on the inner periphery side. In the example shown in (B), the connection portion 12 of the internal fixation device 1 is disposed on the inner periphery side, and the connection portion 21 of the outer tube 2 is disposed on the outer periphery side. Each of the connection portions 12 and 21 has a screw thread formed thereon, and is connected by being rotated and inserted.

[0152] When the internal fixation device 1 has a self-tapping thread 15 that can be screwed into the pedicle, the threads formed on the connection portions 12 and 21 should be configured with a thread in the opposite direction to the self-tapping thread 15. For example, when the self-tapping thread 15 is screwed into the bone hole of the pedicle by rotating the internal fixation device 1 clockwise, a counterclockwise force must be applied to remove the device. Since the connection portions 12 and 21 are required not to loosen due to this counterclockwise force, they should be configured with a thread in the opposite direction to the self-tapping thread 15.

[0153] 8 is a cross-sectional view showing a schematic diagram of another example of the structure of the connection portions 12 and 21 between the internal fixation device 1 and the outer tube 2. (A) is a bird's-eye view, (B) is a front view, and (C) is a cross-sectional view. (A) and (B) are not cross-sectional views, but the outer tube 2 side is hatched to facilitate understanding.

[0154] The connecting portion 21 of the outer tube 2 has a convex portion 211, and the connecting portion 12 of the internal fixation device 1 has a vertical groove 121 through which the convex portion 211 passes when the outer tube 2 is advanced along the central axis toward the internal fixation device 1 to connect with the connecting portion 12, and a horizontal groove 122 into which the convex portion 211 fits when the convex portion 211 reaches the proximal end of the vertical groove 121 and is rotated around the central axis in a direction opposite to the direction in which the tapping screw thread 15 is screwed in, thereby restricting further rotation in the opposite direction and linear disconnection along the central axis.

[0155] 7 , the outer tube 2 is connected to the internal fixation device 1 so as not to loosen even when rotated when removing the internal fixation device 1. The convex portion 211 of the outer tube 2 is advanced linearly in the central axial direction of the internal fixation device 1 within the vertical groove 121 to its end, and then the outer tube 2 is rotated to advance it into the horizontal groove 122. Because the rotation direction is opposite to the direction in which the tapping screw threads 15 of the internal fixation device 1 are screwed in, the connection between the outer tube 2 and the internal fixation device 1 is not released by the action of turning the outer tube 2 to rotate the internal fixation device 1 for removal. Furthermore, since the connection between the outer tube 2 and the internal fixation device 1 is not released even by a linear force, the connection between the outer tube 2 and the internal fixation device 1 is maintained stably even when the internal fixation device 1 is removed without rotating the internal fixation device 1, for example, while destroying the thread groove of the weakened pedicle bone hole.

[0156] The "details of the internal fixation device" described here are not limited to this third embodiment, but can be similarly applied to other embodiments, including those described later.

[0157] 9 is an explanatory diagram showing a cross-sectional structure of a treatment instrument 10 according to a fourth embodiment. In the treatment instrument 10, a fourth through-hole 49 may be provided in the bone drilling inner cylinder 4, penetrating it from the distal end to the tip. This allows the treatment instrument 10 of the present invention to be inserted into the pedicle along the guide pin.

[0158] 21 , before step 4, a guide pin is inserted from the incision in the skin 90 toward the pedicle 91, and in step 4, the integrated treatment instrument 10 is inserted along the guide pin so that it passes through the fourth through-hole 49. After inserting the treatment instrument 10, the guide pin is removed, and the procedure can proceed to step 5 and subsequent steps in which the treatment instrument 10 is inserted further deeply into the pedicle 91.

[0159] [Embodiment 5] Figures 10A to 10E are explanatory diagrams showing a schematic cross-sectional structure of a treatment instrument 10 of embodiment 5 as viewed from the front. X-Y cross sections are also shown in Figures 10A and 10E. In this embodiment 5, a connection mechanism for connecting the outer tube 2 and the driver 3 is provided at the distal end of the treatment instrument 10 of embodiments 1 to 4. This connection mechanism may be configured to further connect the driver 3 and the bone drilling inner tube 4. This embodiment 5 can also be used with a cement separation instrument 800, which will be described later in embodiment 11. Figures 10A to 10E show an example in which the outer tube 2 has an outer tube side thread 22 within its through-hole 29, which, together with the cement separation instrument 800, constitutes a motion direction conversion mechanism. However, this outer tube side thread 22 is not an essential component of this embodiment 5.

[0160] 10A shows a state in which the internal fixation device 1, outer cylinder 2, driver 3, and bone drilling inner cylinder 4 are connected. The outer cylinder 2 and driver 3 have connection mechanisms 200 and 300, respectively, and when the fitting portion 33 at the tip is fitted into the fitting portion 13 of the head 11 of the internal fixation device 1 to which the outer cylinder 2 is connected, these connection mechanisms 200 and 300 allow the driver 3 to be detachably connected to the outer cylinder 2 connected to the internal fixation device 1. In the connected state, the latch protrusion 301 of the driver 3 contacts and connects with the proximal side of the latch protrusion 201 of the outer cylinder 2, and at this time, the internal fixation device 1 and outer cylinder 2 are connected at the connection portions 12 and 21, and the internal fixation device 1 and driver 3 are fitted together at the fitting portions 13 and 33, so that the internal fixation device 1, outer cylinder 2, and driver 3 are integrated. The gap between the distal end of the connection mechanism 200 of the outer tube 2 and the connection mechanism 300 (handle 303 in Figures 10A to 10E) can also be used as an indicator of whether the connection state between the outer tube 2 and the internal fixation device 1 and the fitting state between the driver 3 and the internal fixation device 1 are appropriate.

[0161] If the connection mechanism 300 of the driver 3 is provided with a handle 303, the rotation of the driver 3 can be restricted or rotated with little force by manipulating the handle 303. For example, the internal fixation device 1 can be screwed into or removed from a bone hole in a pedicle. The driver 3 may further be configured to be able to connect a bone drilling inner tube 4. For example, the distal ends of the driver 3 and the bone drilling inner tube 4 may be provided with connection portions 305 and 405, for example, consisting of interlocking threads. Furthermore, when the internal fixation device 1, the outer tube 2, and the driver 3 are integrated, and the bone drilling inner tube 4 is inserted into the through-holes 39 and 19 communicating with the driver 3 and the internal fixation device 1 and connected at the distal end by the connection portions 305 and 405, the bone drilling portion 41 at the tip of the bone drilling inner tube 4 protrudes from the tip of the internal fixation device 1. Furthermore, the bone drilling inner tube 4 may be provided with a handle 403 and a connection portion 304 that is connected to the handle 303 of the driver 3. Alternatively, the connection mechanism between the driver 3 and the bone drilling inner tube 4 can be any other form, such as by providing a groove on the outer periphery of the handle 303 of the driver 3, placing the handle 403 of the bone drilling inner tube 4 over the outer periphery of the handle 303 of the driver 3, and providing a latch-type protrusion on the inner periphery of the handle 403 of the bone drilling inner tube 4 that fits into the groove on the outer periphery of the handle 303.

[0162] The connection mechanisms 200 and 300 are configured to be detachable by moving the driver 3 along the central axis within the through-hole 29 of the outer tube 2. A more specific example is as follows. Fig. 10B shows a state before the driver 3 is connected to the outer tube 2 connected to the internal fixation device 1, and Fig. 10C shows a state after the driver 3 is connected to the outer tube 2 connected to the internal fixation device 1. The connection mechanism 200 of the outer tube 2 has a latch protrusion 201 formed on the distal end of the outer tube 2 in a direction away from the central axis. The connection mechanism 300 of the driver 3 is configured to include an elastic body, for example, a latch protrusion 301 and a leaf spring 302, and is configured so that the leaf spring 302 is deflected by a force that moves the driver 3 along the central axis within the through-hole 29 of the outer tube 2, allowing the latch protrusion 301 to pass over and pass over the latch protrusion 201 of the outer tube 2. The cross-sectional shape of the latch protrusion 201 of the outer cylinder 2 may be trapezoidal as shown in the figure, or may be triangular, triangular with blunted ends, or semicircular.

[0163] The connection mechanisms 200 and 300 are configured so that the driver 3 and the outer tube 2 can rotate relative to each other around a central axis. As shown in the X-Y cross section of FIG. 10A , the connection mechanism 200 of the outer tube 2 preferably includes a wrench fitting portion 202 on the distal side near the end. The connection between the internal fixation device 1 and the outer tube 2 at the connection portions 12 and 21 can be released by fitting a wrench into the wrench fitting portion 202 and rotating the outer tube 2 while preventing rotation of the internal fixation device 1, whose fitting portions 33 and 13 are fitted together, using the driver 3. This also effectively functions to prevent rotation of the internal fixation device 1 and the outer tube 2 when rotating the cement separation device 800 in the following embodiments 11 and 12.

[0164] 10D shows a state in which the outer tube 2 has been removed from the internal fixation device 1 while the outer tube 2 and the driver 3 are connected to each other. If the moving distance required to completely remove the connection portion 21 of the outer tube 2 from the connection portion 12 of the internal fixation device 1 is Lp, the connection mechanism 300 has a space of length Lr sufficient to allow the latch convex portion 201 at the distal end of the outer tube 2 to move a distance greater than this along the central axis from the latch protrusion 301 on the driver 3 side. Furthermore, the wrench fitting portion 202 is designed to leave a length Lq sufficient to allow a wrench to be inserted below the lower end of the connection mechanism 300 of the driver 3 even when the connection portion 21 of the outer tube 2 is removed from the connection portion 12 of the internal fixation device 1.

[0165] 10E shows an example of the configuration of connection mechanisms 300 and 200 provided on the driver 3 and outer cylinder 2 integrated with the bone-drilling inner cylinder 4 described below in the following Embodiment 6. The configuration and operation of the connection mechanisms 300 and 200 are the same as those shown in FIGS. 10A to 10D. When the outer cylinder 2 is connected to the internal fixation device 1 at the proximal end and the driver 3 is connected at the distal end by the connection mechanisms 200 and 300, the bone-drilling portion 41 at the tip of the bone-drilling inner cylinder 4, which is configured integrally with the driver 3, is configured to protrude beyond the tip of the internal fixation device 1.

[0166] As described above, the outer cylinder 2 and the driver 3 are integrated, and the bone drilling inner cylinder 4 can also be integrated, allowing the procedure of forming a bone hole in the pedicle to be performed stably, while in other procedures the bone drilling inner cylinder 4 can be removed to allow the insertion of other instruments such as guide pins.

[0167] The connection structure of this fifth embodiment is not limited to the above-described first to fourth embodiments, but can also be similarly adopted in the treatment device 10 of other embodiments described below.

[0168] [Embodiment 6] Fig. 11 is an explanatory diagram schematically showing a cross-sectional structure to illustrate an example of the configuration of a treatment instrument 10 of Embodiment 6. In Embodiments 3, 4, and 5, the bone drilling inner cylinder 4 is separate from the driver 3 and is configured to be inserted into the through-hole 39 of the driver 3 to be integrated. On the other hand, in the treatment instrument 10 of Embodiment 6, the bone drilling inner cylinder 4 is integrated as part of the driver 3. That is, the driver 3 in the treatment instrument 10 of Embodiment 6 includes the bone drilling inner cylinder 4 that extends proximally from the tip of the fitting portion 33. The bone drilling inner cylinder 4 has a bone drilling portion 41 that protrudes from the tip through the through-hole 19 of the internal fixation instrument 1 when the fitting portion 33 of the driver 3 is fitted into the fitting portion 13 of the internal fixation instrument 1.

[0169] This allows the internal fixation device 1 to be introduced into the vertebral body 92 from the pedicle 91 while forming a bone hole in the pedicle 91 using the driver 3 with the bone drilling inner cylinder 4, thereby simplifying the procedure.

[0170] 12 and 13 are partial front views schematically illustrating an example of the configuration of a driver 3 with an integrated bone drilling inner tube 4. The bone drilling inner tube 4 is integrally attached proximally to the fitting portion 33 of the driver 3, which is fitted into the fitting portion 13 of the internal fixation device 1. Various shapes can be selected for the bone drilling portion 41 at the tip. The bone drilling portion 41 illustrated in FIG. 12 has a shape in which several sides are cut flat around a truncated cone. The bone drilling portion 41 illustrated in FIG. 13 is an example in which a screw thread 42 is formed around the truncated cone. The screw thread 42 is preferably formed to follow the same path as the tapping screw thread 15 of the internal fixation device 1 into which the driver 3 is fitted. This allows the bone drilling inner tube 4 to easily form a bone hole in the pedicle 91 and the internal fixation device 1 to be smoothly inserted into the formed bone hole.

[0171] The driver 3 with the bone drilling inner cylinder 4 may be provided with a connecting portion that allows it to be attached and detached to the distal end of the outer cylinder 2 when fitted into the fitting portion 13 of the internal fixation device 1. The connecting portion is not particularly limited, and may be, for example, the connecting structure exemplified in the fifth embodiment or a latch structure that can be attached and detached by operating a lever. Furthermore, if a handle is formed at the distal end, this is suitable for rotating the bone drilling portion and the internal fixation device 1. This allows the driver with the bone drilling inner cylinder to be integrated with the outer cylinder, stabilizing the procedure of forming a bone hole in the pedicle using the bone drilling inner cylinder.

[0172] 24 and 25 are explanatory views showing the procedure for the surgical procedure for implanting the internal fixation device 1. The first half is shown in Fig. 24, and the second half is shown in Fig. 25. Fig. 26 is an explanatory view showing the procedure for the surgical procedure for removing the internal fixation device 1.

[0173] An example of a procedure for implanting the internal fixation device 1 into the body will be described below. Steps 1 and 2 are preparatory steps.

[0174] Step 1: Connect the outer tube 2 to the internal fixation device 1. The connection part 21 at the tip of the outer tube 2 is screwed counterclockwise into the connection part 12 of the head part 11 of the internal fixation device 1 to connect them.

[0175] Step 2: The driver 3 with the bone drilling inner cylinder 4 of the sixth embodiment is inserted into the connected internal fixation device 1 and outer cylinder 2 and connected together. The treatment device 10 is integrated.

[0176] Step 3 ([1] in Figure 24): The treatment instrument 10 integrated in steps 1 and 2 is inserted directly into the incision. The treatment instrument 10 is inserted while being checked with an intraoperative X-ray, and is advanced until the tip touches the bone (vertebral arch).

[0177] Step 4 ([2]): If the position where the tip of the treatment instrument 10 will hit is appropriate, the head of the driver 3 with the bone-drilling inner tube 4 is struck with a hammer, or the entire treatment instrument 10 is screwed in, thereby advancing the proximal side of the internal fixation instrument 1 into the pedicle 91 until the tip reaches the entrance of the vertebral body 92.

[0178] Step 5 ([3]): The driver 3 with the bone drilling inner cylinder 4 is removed from the treatment instrument 10. The internal fixation instrument 1 and the outer cylinder 2 connected thereto remain.

[0179] Step 6 ([4]): A bone excavation tool 25 is inserted into the through-holes (through-holes 19 and 29) that communicate with the internal fixation device 1 and the connected outer tube 2 to excavate the inside of the vertebral body 92. The bone excavation tool 25 may be a straight excavation tool such as a drill, or may be an instrument with a bent tip that can excavate the surrounding area. The through-holes 19 and 29 are larger than those in the example of embodiment 1 shown in [4] of Figure 21 by the amount that the driver 3 is not inserted, and therefore a thicker bone excavation tool 25 or the like can be inserted.

[0180] Step 7 ([5]): Instead of the bone drilling tool 25, a balloon catheter 26 is inserted through the communicating through-holes (through-holes 19 and 29) of the internal fixation device 1 and the connected outer cylinder 2, and a cavity is formed by inflating the balloon 27 inside the vertebral body 92. At the same time, the vertebral body 92 is restored to its original state due to the compression fracture.

[0181] Step 8 ([6]): The balloon 27 is de-inflated and the balloon catheter 26 is withdrawn from the through-holes (through-holes 19 and 29), leaving a cavity 28 in the vertebral body 92. The cement filling tube 5 is inserted through the through-holes (through-holes 19 and 29), and bone cement pre-filled in the cement filling tube 5 is injected using the cement pushing rod 6. By preparing multiple cement filling tubes 5 pre-filled with bone cement and filling each of the left and right pedicles three to four times, an appropriate amount of bone cement can be filled. The cavity 28 in the vertebral body 92 may be filled with bone cement using a separate tool that applies pressure to the cement filling tube 5 from a syringe or the like to inject and fill the bone cement.

[0182] Step 9 ([7] in Figure 25): After removing the cement filling tube 5 and the cement pushing rod 6, insert the driver 3 with the bone-drilling inner cylinder 4 into the communicating through-holes (through-holes 19 and 29) of the internal fixation device 1 and the connected outer cylinder 2, and return it to the integrated treatment device 10.

[0183] Step 10 ([8]): The entire treatment instrument 10 is rotated to screw the internal fixation device 1 into the bone cement 50. Since the tapping screw threads 15 are formed on the outer periphery of the internal fixation device 1, the internal fixation device 1 is advanced into the bone hole formed in the pedicle 91 while tapping, and is fixed. The bone cement 50 that has filled the cavity 28 in the vertebral body 92 and formed a mass has not yet hardened at this point, and the proximal side of the internal fixation device 1 is inserted into the bone cement 50.

[0184] Step 11 ([9]): The driver 3 with the bone-drilling inner cylinder 4 is removed and pulled out, and the cement molding instrument 7 is inserted into the bone cement 50 through the through-holes (through-holes 19 and 29) that communicate with the remaining internal fixation device 1 and outer cylinder 2. A hole is formed in the bone cement 50 at the end of the through-hole 19 of the internal fixation device 1 with the cement molding instrument 7, and the bone cement 50 is molded into a predetermined shape.

[0185] Step 12 (

[10] ): The cement molding instrument 7 is removed. A hole having a desired shape is formed in the bone cement 50 at the bottom of the through-hole 19 of the internal fixation instrument 1 by the tip of the cement molding instrument 7. The depth of the hole formed in the bone cement 50 can be adjusted to an appropriate depth, for example, about 1 cm from the tip of the internal fixation instrument 1.

[0186] Step 13 (

[11] ): After removing the outer tube 2, the wound is closed (the incision is closed by suturing). The outer tube 2 is removed by rotating it clockwise to loosen the connecting parts 12 and 21. [11'] in Figure 25 will be described later.

[0187] As described above, in the treatment instrument 10 of the present invention, the internal fixation device 1 and the outer cylinder 2 are connected to each other, and the through-hole 19 and the through-hole 29 communicate with each other, functioning as a guide for sequentially introducing the driver 3 with the bone-drilling inner cylinder 4, the balloon catheter 26, and the cement-filling tube 5 into the vertebral body 92 (steps 6, 7, and 8, [4], [5], and [6] in FIG. 24). Furthermore, while the internal fixation device 1 and the outer cylinder 2 are connected, the driver 3 with the bone-drilling inner cylinder 4 is inserted through the through-hole 29, fitted into the head of the internal fixation device 1, and rotated (step 10, [7] in FIG. 25). This allows the internal fixation device 1 to be screwed into the bone cement 50 filled in the vertebral body 92. At this time, the tapping thread 15 formed on the distal side of the internal fixation device 1 taps the bone hole in the pedicle 91, while pushing the tip of the shaft 14 on the proximal side of the internal fixation device 1 into the bone cement 50. In this way, the procedure can be carried out by simply sequentially exchanging the instruments to be inserted while the internal fixation instrument 1 and the outer cylinder 2 remain connected, thereby simplifying the procedure.

[0188] An example of a procedure for removing the internal fixation device 1 will be described with reference to FIG.

[0189] Step 1 ([1]): The skin is incised to expose the head 11 of the internal fixation device 1 through the wound incision 93.

[0190] Step 2 ([2]): Connect the outer cylinder 2 to the head 11 of the internal fixation device 1.

[0191] Step 3 ([3]): Insert the driver 3 with the bone-drilling inner cylinder 4 into the through-hole (the through-hole communicating with the through-hole 19 and the through-hole 29) formed by connecting the internal fixation device 1 and the outer cylinder 2, and fit the fitting portion 33 into the fitting portion 13 on the head of the internal fixation device 1.

[0192] Step 4 ([4]): The driver 3 with the bone drilling inner cylinder 4 and the outer cylinder 2 are turned counterclockwise to remove the internal fixation device 1 from the bone cement 50 and the pedicle 91.

[0193] Step 5 ([5]): After removing the driver 3 with the bone drilling inner cylinder 4 and the outer cylinder 2, the wound 93 is closed. The driver 3 with the bone drilling inner cylinder 4 may be removed first, and then the internal fixation device 1 connected to the outer cylinder 2 may be removed, or the internal fixation device 1, the outer cylinder 2, and the driver 3 with the bone drilling inner cylinder 4 may be removed while still connected together.

[0194] Steps 3 to 4 for rotating the internal fixation device 1 in the reverse direction to remove it do not necessarily require the use of a driver 3 with a bone-drilling inner cylinder 4, and a step using a driver 3 with a separate bone-drilling inner cylinder 4 may also be adopted, as shown in Figure 23. Furthermore, if the internal fixation device 1 is not firmly bonded to the bone cement 50, the outer cylinder 2 may be rotated and removed without using a driver 3, regardless of whether the bone-drilling inner cylinder 4 is integrated or separate.

[0195] Seventh Embodiment FIG. 14 is an explanatory diagram showing a cross-sectional structure of a treatment device 10 according to a seventh embodiment.

[0196] In the treatment instrument 10 of the sixth embodiment described above, the driver 3 with the bone-drilling inner tube 4 may have a third through-hole 39 that penetrates from the distal end to the tip of the bone-drilling inner tube. This allows the treatment instrument 10 to be inserted into the pedicle along the guide pin, as in the second embodiment.

[0197] 27 and 28 are explanatory views showing the procedure for the surgical procedure to implant the internal fixation device 1. The first half is shown in Fig. 27, and the second half is shown in Fig. 28. Fig. 29 is an explanatory view showing the procedure for the surgical procedure to remove the internal fixation device 1.

[0198] An example of a procedure for implanting the internal fixation device 1 into the body will be described. Steps 1 to 3 are preparatory procedures. Since these are the same as those in the third embodiment, their explanation will be omitted.

[0199] Step 3 ([1] in Figure 24): The treatment instrument 10 integrated in steps 1 and 2 is inserted directly into the incised wound. A guide pin (not shown) may be inserted in advance, and then inserted into the through-hole 39, along which the driver 3 with the bone-boring inner cylinder 4 is aligned, and the entire treatment instrument 10 is inserted. When the position where the tip of the treatment instrument 10 abuts is appropriate, the guide pin is removed.

[0200] Step 4 ([2]): By striking the head of the driver 3 with the bone-drilling inner cylinder 4 with a hammer or by screwing the entire treatment instrument 10, the proximal side of the internal fixation instrument 1 is advanced into the pedicle 91 until the tip reaches the entrance of the vertebral body 92.

[0201] Step 5 ([3]): A bone excavation tool 25 is inserted through the through-hole 39 of the driver 3 with the bone drilling inner tube 4 to excavate the inside of the vertebral body 92. The bone excavation tool 25 may be a straight excavation tool such as a drill, or may be an instrument with a bent tip that can excavate the surrounding area.

[0202] Step 6 ([4]): A balloon catheter 26 is inserted through the through-hole 39 instead of the bone drilling tool 25, and a balloon 27 is inflated within the vertebral body 92 to form a cavity. At the same time, deformation of the vertebral body 92 due to the compression fracture is repaired.

[0203] Step 7 ([5]): The balloon 27 is de-inflated and the balloon catheter 26 is withdrawn from the through-hole 39, leaving a cavity 28 in the vertebral body 92. The cement filling tube 5 is inserted through the through-hole 39, and the bone cement previously filled in the cement filling tube 5 is injected using the cement pushing rod 6. The filling of the cavity 28 in the vertebral body 92 with bone cement may be performed using another tool that applies pressure from a syringe or the like to the cement filling tube 5 to inject and fill the bone cement.

[0204] Step 8 ([6]): After removing the cement filling tube 5 and the cement pushing rod 6, turn the driver 3 with the bone drilling inner cylinder 4 to screw the internal fixation device 1 into the pedicle 91 and the bone cement 50.

[0205] Step 9 ([7]): Insert the cement molding instrument 7 into the through-hole 39 of the driver 3 with the bone drilling inner cylinder 4, form a hole in the bone cement 50 at the end of the through-hole 19 of the internal fixation instrument 1, and mold it into a predetermined shape.

[0206] Step 10 ([8]): Remove the cement molding instrument 7. A hole shaped to a desired shape is formed in the bone cement 50 at the bottom of the through-hole 19 of the internal fixation device 1 by the tip of the cement molding instrument 7.

[0207] Step 11 ([9]): After removing the driver 3 with the bone drilling inner cylinder 4 and the outer cylinder 2, the wound is closed (the incision is closed by suturing). The outer cylinder 2 is removed by rotating it clockwise to loosen the connecting parts 12 and 21. [9'] in Figure 28 will be described later.

[0208] Steps 10 and 11 ([7] and [8]) of inserting the cement molding tool 7 to form and mold a hole for fixing the bone cement 50 may be omitted.

[0209] As described above, by providing a through hole 39 in the driver 3 with the bone drilling inner tube 4, a guide pin, a bone drilling tool 25, a balloon catheter 26, a cement filling tube 5 and a cement pushing rod 6, a cement molding tool 7, etc. can be introduced into the vertebral body 92 through the through hole 39.

[0210] An example of a procedure for removing the internal fixation device 1 will be described with reference to FIG.

[0211] Step 1 ([1]): The skin is incised to expose the head 11 of the internal fixation device 1 through the wound incision 93.

[0212] Step 2 ([2]): Connect the outer cylinder 2 to the head 11 of the internal fixation device 1.

[0213] Step 3 ([3]): Insert the driver 3 with the bone-drilling inner tube 4 into the through holes 19 and 29 that communicate when the internal fixation device 1 and the outer tube 2 are connected, and fit the fitting portion 33 into the fitting portion 13 of the head 11 of the internal fixation device 1.

[0214] Step 4 ([4]): Insert the cement fixing tool 8 into the through hole 39 of the driver 3 with the bone drilling inner tube 4, and fit its tip into the hole formed by the cement molding tool 7 and shaped to a predetermined shape.

[0215] Step 5 ([5]): While holding the bone cement 50 with the cement fixation device 8, turn the driver 3 with the bone drilling inner cylinder 4 and the outer cylinder 2 counterclockwise to remove the internal fixation device 1 from the bone cement 50 and the pedicle 91.

[0216] Step 6 ([6]): After the tapping screw threads 15 are released from the pedicle 91, the screwed internal fixation device 1 can be pulled out while still connected to the outer tube 2. After the internal fixation device 1 connected to the outer tube 2 and the driver 3 with the bone drilling inner tube 4 are removed, the wound 93 is closed. The driver 3 with the bone drilling inner tube 4 may be pulled out first, and then the internal fixation device 1 connected to the outer tube 2 may be pulled out, or the internal fixation device 1, the outer tube 2, and the driver 3 with the bone drilling inner tube 4 may be pulled out while still connected together.

[0217] Steps 4 to 5 ([4] to [5]) show an example assuming the use of the cement fixation instrument 8, but if the internal fixation instrument 1 is not firmly bonded to the bone cement 50, this step may be omitted and the internal fixation instrument 1 may be removed from the bone cement 50 simply by turning the driver 3 with the bone drilling inner cylinder 4. Furthermore, if the internal fixation instrument 1 is not firmly bonded, step 3 ([3]) may also be omitted and the internal fixation instrument 1 may be removed simply by turning the outer cylinder 2 without using the driver 3 with the bone drilling inner cylinder 4.

[0218] Eighth Embodiment FIG. 15 is an explanatory diagram showing a configuration example of a treatment device 10 according to an eighth embodiment.

[0219] The treatment device 10 of the above-described first to seventh embodiments may further include a cement filling tube 5, a cement pushing rod 6, and a cement fixation device 8. The cement filling tube 5 has a grip 51 at its distal end, and protrudes from the tip through the through-holes 19 and 29 that communicate when the internal fixation device 1 and the outer cylinder 2 are connected to each other.

[0220] When the driver 3 is connected in addition to the internal fixation device 1 and the outer tube 2 as exemplified in embodiment 2, the cement filling tube 5 protrudes from the tip through the through hole communicating with the through hole 39 of the driver 3. When the bone drilling inner tube 4 having the through hole 49 is inserted into the through hole 39 of the driver 3 as exemplified in embodiment 3, the cement filling tube 5 protrudes from the tip through the through hole 49. When the driver 3 with the bone drilling inner tube 4 is inserted into the through hole communicating between the internal fixation device 1 and the outer tube 2, if the driver 3 with the bone drilling inner tube 4 does not have the through hole 39 as exemplified in embodiment 6, the cement filling tube 5 protrudes from the through hole communicating between the internal fixation device 1 and the outer tube 2 after the driver 3 with the bone drilling inner tube 4 is removed, or if the driver 3 with the bone drilling inner tube 4 has the through hole 39 as exemplified in embodiment 7, the cement filling tube 5 protrudes from the through hole 39. In either case, the cement filling tube 5 protrudes from the tip through the through holes 19 and 29 that communicate when the internal fixation device 1 and the outer tube 2 are connected to each other.

[0221] The cement pushing rod 6 has a second grip 61 inserted along the central axis of the cement filling tube 5 and detachably connected to the first grip 51 at its distal end, and a cement molding portion 62 inserted along the central axis of the cement filling tube 5 and protruding from its tip. Like the cement filling tube 5, the cement fixing device 8 also protrudes from the tip of the internal fixation device 1 through a communicating through-hole when the internal fixation device 1 and the outer tube 2 are connected to each other, or when the driver 3 is also connected. The cement fixing portion 82 protruding from the tip of the internal fixation device 1 is inserted into a hole formed in the bone cement within the vertebral body by the cement molding portion 62. This further facilitates removal of the internal fixation device 1. When the internal fixation device 1 is removed after filling with bone cement 50, fitting the tip of the cement fixing device 8 into the hole formed when the internal fixation device 1 was inserted can prevent the bone cement 50 from rotating within the vertebral body and facilitate the operation of rotating and removing the internal fixation device 1.

[0222] 16 is an explanatory diagram showing an example of the configuration of the cement pushing rod 6 and the cement fixing device 8. The shapes of the tip portions of the cement pushing rod 6 and the cement fixing device 8 are shown. The part inserted into the internal fixation device 1 is shown in cross section, and the protruding part is shown in front view. The cement filling tube 5 is inserted up to the tip of the internal fixation device 1, and the cement molding part 62 at the tip of the cement pushing rod 6 protrudes from the tip.

[0223] The upper row A shows an example in which a tapping screw thread is formed at the tip of the cement fixing device 8, and the cement fixing device 8 is inserted into a hole without a thread groove while tapping the side wall to fix the bone cement 50. The cement molding part 62 at the tip of the cement pushing rod 6 is cylindrical, or a tapered cylindrical or conical shape whose diameter decreases toward the tip, and the cement fixing part 82 at the tip of the cement fixing device 8 has a tapping screw thread formed around the periphery of the same shape.

[0224] The middle and bottom rows (B and C) show examples in which the cement shaping portion 62 at the tip of the cement pusher rod 6 and the cement fixation portion 82 at the tip of the cement fixation device 8 have the same thread, and the thread of the cement fixation portion 82 of the cement fixation device 8 is screwed into the thread groove formed in the cement shaping portion 62 of the cement pusher rod 6 to fix the bone cement 50. The cement shaping portion 62 at the tip of the cement pusher rod 6 is cylindrical, tapered cylindrical, or conical, with a diameter decreasing toward the tip, and its outer periphery is provided with a formed thread that forms a thread groove in a hole formed in the bone cement 50. In the example of the middle row (B), the cement fixation portion 82 at the tip of the cement fixation device 8 has the same shape and a tapping thread formed around its periphery, and the tapping thread of the cement fixation device 8 fits into the thread groove formed by the formed thread of the cement shaping portion 62. The bottom row (C) shows an example in which a trapezoidal thread is used instead of a tapping thread.

[0225] As a result, the cement fixation device 8 fits into the thread groove formed by the cement molding part 62 at the tip of the cement pushing rod 6, and can more firmly restrain the rotation of the bone cement 50, making it easier to remove the internal fixation device 1. Furthermore, by configuring the cement fixation device 8 to protrude significantly from the tip of the internal fixation device 1, not only can the rotation of the bone cement 50 be restrained, but also a linear pushing force can be applied to the bone cement 50, making it easier to separate the internal fixation device 1 from the bone cement 50 and remove it.

[0226] Ninth Embodiment FIG. 17 is an explanatory diagram showing a configuration example of a treatment device 10 according to a ninth embodiment.

[0227] The treatment instrument 10 of the above-described first to seventh embodiments may further include a cement molding instrument 7 and a cement fixation instrument 8. The cement molding instrument 7 has a cement molding part 72 that protrudes from the tip through a through-hole that communicates when the internal fixation instrument 1 and the outer cylinder 2 are connected to each other.

[0228] The cement molding instrument 7 is similar to the cement filling tube 5 of embodiment 7. When the driver 3 is connected in addition to the internal fixation instrument 1 and the outer tube 2 as exemplified in embodiment 3, the cement molding instrument 7 is inserted through a through-hole communicating with the through-hole 39 of the driver 3, and the cement molding portion 72 protrudes from the tip. When the bone drilling inner tube 4 having a through-hole 49 is inserted into the through-hole 39 of the driver 3 as exemplified in embodiment 4, the cement molding instrument 7 is inserted through the through-hole 49, and the cement molding portion 72 protrudes from the tip. When the driver 3 with the bone drilling inner tube 4 is inserted into the through-hole communicating between the internal fixation instrument 1 and the outer tube 2, as exemplified in embodiment 5, if the driver 3 with the bone drilling inner tube 4 does not have a through-hole 39, the cement molding instrument 7 is inserted through the through-hole communicating between the internal fixation instrument 1 and the outer tube 2 after removing the driver 3 with the bone drilling inner tube 4, and the cement molding portion 72 protrudes from the tip. On the other hand, if the driver 3 with the bone drilling inner cylinder 4 has a through-hole 39 as exemplified in the sixth embodiment, it is inserted through the through-hole 39, and the cement molding part 72 protrudes from the tip. In either case, it is configured so that it is inserted through the through-hole that communicates when the internal fixation device 1 and the outer cylinder 2 are connected to each other, and the cement molding part 72 protrudes from the tip.

[0229] Like the cement molding instrument 7, the cement fixation instrument 8 is inserted through a through-hole that communicates when the internal fixation instrument 1 and the outer cylinder 2 are connected to each other, and a cement fixation portion 82 protrudes from the tip. The cement fixation portion 82 at the tip of the cement fixation instrument 8 is inserted into a hole formed in the bone cement inside the vertebral body by the cement molding portion 72 of the cement molding instrument 7, and fixes the bone cement 50. This makes it even easier to remove the internal fixation instrument 1. After filling the bone cement 50 and inserting the internal fixation instrument 1, fitting the tip of the cement fixation instrument 8 into the hole formed using the cement molding instrument 7 when removing the internal fixation instrument 1 prevents the bone cement 50 from rotating inside the vertebral body, facilitating the operation of rotating and removing the internal fixation instrument 1.

[0230] 18 is an explanatory diagram showing an example of the configuration of the cement molding instrument 7 and the cement fixing instrument 8. The shapes of the tip portions of the cement molding instrument 7 and the cement fixing instrument 8 are shown. The portion inserted into the internal fixation instrument 1 is shown in a cross-sectional view, and the protruding portion is shown in a front view. The cement molding portion 72 of the cement molding instrument 7 protrudes from the tip of the internal fixation instrument 1.

[0231] The upper row A shows an example in which a tapping screw thread is formed at the tip of the cement-fixing instrument 8, and the cement-fixing instrument 8 is inserted into a hole without a thread groove while tapping the side wall to fix the bone cement 50. The cement-molding part 72 at the tip of the cement-molding instrument 7 is cylindrical, or a tapered cylindrical or conical shape whose diameter decreases toward the tip, and the cement-fixing part 82 at the tip of the cement-fixing instrument 8 has a tapping screw thread formed around the periphery of the same shape.

[0232] The middle row (B) and the bottom row (C) show examples in which the cement molding portion 72 at the tip of the cement molding instrument 7 and the cement fixing portion 82 at the tip of the cement fixing instrument 8 have the same thread, and the thread of the cement fixing portion 82 of the cement fixing instrument 8 is screwed into the thread groove formed by the cement molding portion 72 of the cement molding instrument 7 to fix the bone cement 50. The cement molding portion 72 at the tip of the cement molding instrument 7 is cylindrical, or tapered cylindrical or conical in shape with a diameter decreasing toward the tip, and its outer periphery is provided with a formed thread that forms a thread groove in a hole formed in the bone cement 50. In the example of the middle row (B), the cement fixing portion 82 at the tip of the cement fixing instrument 8 has a tapping thread formed around its same shape, and the tapping thread of the cement fixing instrument 8 fits into the thread groove formed by the formed thread of the cement molding portion 72. The bottom row (C) shows an example in which a trapezoidal thread is used instead of a tapping thread.

[0233] As a result, the cement fixation device 8 fits into the thread groove formed by the cement molding part 72 at the tip of the cement molding device 7, and can more firmly suppress the rotation of the bone cement 50, making it easier to remove the internal fixation device 1. Furthermore, by configuring the cement fixation device 8 to protrude significantly from the tip of the internal fixation device 1, not only can the rotation of the bone cement 50 be suppressed, but also a linear pushing force can be applied to the bone cement 50, making it easier to separate the internal fixation device 1 from the bone cement 50 and remove it.

[0234] [Connection Mechanism] The connection mechanism of Embodiment 5 can be applied to the cement molding instrument 7 of this eleventh embodiment. Fig. 10F is a cross-sectional view schematically showing an example of a configuration in which the connection structure of Embodiment 5 is applied to the cement molding instrument 7. The cement molding instrument 7 can include a connection mechanism 700 that is essentially the same as the connection mechanism 400 for the bone drilling inner tube 4 shown in Fig. 10A. The connection mechanism 700 of the cement molding instrument 7 includes a connection part 705 formed of a thread that meshes with a connection part 305 provided at the distal end of the driver 3 for connecting to the bone drilling inner tube 4. The cement molding instrument 7 includes a handle 703, which may be connected to the handle 303 via the connection part 304 of the driver 3, etc. Furthermore, when the internal fixation device 1, outer tube 2, and driver 3 are integrated, and the cement molding device 7 is inserted into the through-holes 39 and 19 that communicate with the driver 3 and the internal fixation device 1, and connected at the distal end by the connecting parts 305 and 705, the cement molding part 72 at the tip of the cement molding device 7 protrudes from the tip of the internal fixation device 1.

[0235] By providing the bone drilling inner cylinder 4 and the cement molding instrument 7 with basically the same connection mechanisms 400 and 700, the procedure of implanting the internal fixation instrument 1 can be completed by sequentially using various instruments including the bone drilling inner cylinder 4 and the cement molding instrument 7, while the internal fixation instrument 1, the outer cylinder 2, and the driver 3 are inserted into the pedicle in an integrated state, thereby simplifying the procedure.

[0236] [Procedure] An example of a surgical procedure for implanting the internal fixation device 1 using a bone drilling inner cylinder 4 and a cement molding instrument 7, which basically have the same connection structure, will be described. More specifically, a bone hole is drilled in the pedicle using the bone drilling inner cylinder 4 having a through-hole 49 as shown in Figures 10A to 10D, and then, when bone cement is injected into the vertebral body and the internal fixation device 1 is screwed in, a hole is formed in the bone cement 50 and molded using the cement molding instrument 7 of this embodiment 9 as shown in Figure 10F.

[0237] 44, 45, and 46 are explanatory views showing the procedure for the surgical procedure of implanting the internal fixation device 1. In Figures 44, 45, and 46, the left and right directions are enlarged compared to other figures such as Figure 21 in order to make the through-hole 49 easier to see.

[0238] Step 1 ([1]): The affected area is incised, and the guide pipe 97 is placed against and grasped on the surface of the pedicle 91. The bone drilling needle 95 is guided through the guide pipe 97 to the pedicle 91, and the pedicle 91 is drilled to form a bone tunnel.

[0239] Step 2 ([2]): The bone drilling needle 95 is removed and the guide pin 96 is passed through the bone hole formed in the pedicle.

[0240] Step 3 ([3]): Remove the guide pipe 97, leaving the guide pin 96.

[0241] Step 4 ([4]): The internal fixation device 1, outer tube 2, driver 3, and bone drilling inner tube 4 are connected and integrated, and the through hole 49 of the bone drilling inner tube 4 is guided along the guide pin 96 into the bone tunnel formed in the pedicle 91. This does not necessarily require prior integration; instead, the internal fixation device 1 and outer tube 2 may be connected and inserted along the guide pin 96, followed by inserting and connecting the driver 3, and then inserting and connecting the bone drilling inner tube 4. As described in the fifth embodiment, the outer tube 2 and driver 3 are configured to be connected only by a force in the linear insertion direction, allowing for a smooth connection. The connection between the driver 3 and bone drilling inner tube 4 illustrated in Figures 44 and 45 is achieved by fitting a latch-type protrusion on the inner circumference of the handle 403 of the bone drilling inner tube 4 into a groove on the outer circumference of the handle 303 of the driver 3. However, the connection may also be achieved by connecting portions 305 and 405 composed of interlocking threads, as shown in Figure 10A.

[0242] Step 5 ([5]): The guide pin 96 is removed, and the integrated internal fixation device 1, outer cylinder 2, driver 3, and bone drilling inner cylinder 4 are inserted into the pedicle 91. A small bone hole is formed in step 1 ([1]), and in this step, the hole is widened to a size that fits the internal fixation device 1 while it is inserted deeply, and the tip of the internal fixation device 1 is stopped just when it reaches the entrance of the vertebral body 92.

[0243] Step 6 ([6]): Remove the bone drilling inner cylinder 4. The through holes 19 and 39 that connect and communicate the internal fixation device 1, outer cylinder 2, and driver 3 function as guides to guide various other instruments into the vertebral body.

[0244] Step 7 ([7] in FIG. 45): A bone excavation tool 25 is inserted into the communicating through-holes 19 and 39 to excavate the inside of the vertebral body 92. The bone excavation tool 25 may be a straight excavation tool such as a drill, or may be an instrument with a bent tip that can excavate the surrounding area.

[0245] Step 8 ([8]): Instead of the bone drilling tool 25, a balloon catheter 26 is inserted into the communicating through-holes 19 and 39, and the balloon 27 is inflated within the vertebral body 92 to restore the vertebral body to its original state due to the compression fracture, and a cavity 28 is formed.

[0246] Step 9 ([9]): The balloon 27 is de-inflated and the balloon catheter 26 is withdrawn, leaving a cavity 28 within the vertebral body 92.

[0247] Step 10 (

[10] ): The cement filling tube 5 is inserted into the communicating through-holes 19 and 39, and the bone cement that has been previously filled in the cement filling tube 5 is injected using the cement pushing rod 6. Instead of the cement filling device consisting of the cement filling tube 5 and the cement pushing rod 6, a cement filling device may be used in which a syringe is connected to the cement filling tube 5 via a tube, and the cement filled in the syringe is pushed out to fill the cavity.

[0248] Step 11 (

[11] ): After removing the cement filling tube 5 and the cement pushing rod 6, the cement molding instrument 7 is inserted through the communicating through-holes 19 and 39 and connected to the driver 3. The cement molding instrument 7 and the driver 3 are integrally connected, and the cement molding portion 72 at the tip of the cement molding instrument 7 protrudes from the tip of the internal fixation device 1 and is inserted into the bone cement 50.

[0249] Step 12 (

[12] ): The cement molding tool 7 and the driver 3, which are integrally connected, are rotated to screw the internal fixation tool 1 into the pedicle 91 and the bone cement 50. The internal fixation tool 1 has a tapping thread 15 formed on its outer periphery, which allows it to advance and fixate by tapping into the bone hole formed in the pedicle 91. The mass of bone cement 50 filled in the cavity 28 in the vertebral body 92 has not yet hardened at this point, and the proximal side of the internal fixation tool 1 is inserted into the bone cement 50. The cement molding portion 72 at the tip of the cement molding tool 7 protrudes from the tip of the internal fixation tool 1 and forms a hole of a predetermined shape in the bone cement 50. By rotating the driver 3 and the cement molding tool 7 in an integrally connected state, the procedure of screwing the internal fixation tool 1 into the pedicle and the procedure of using the cement molding tool 7 to form a hole of a predetermined shape in the bone cement 50 at its tip are performed in a single operation.

[0250] Step 13 (

[13] in FIG. 46): The cement molding instrument 7 is removed. A hole having a predetermined shape is formed in the bone cement 50 at the bottom of the through-hole 19 of the internal fixation instrument 1 by the tip of the cement molding instrument 7. The depth of the hole formed in the bone cement 50 can be adjusted to an appropriate depth, for example, about 1 cm from the tip of the internal fixation instrument 1.

[0251] Step 14 (

[14] ): Rotate the outer cylinder 2 clockwise to loosen and remove the connectors 12 and 21, and remove it together with the driver 3. After removing the driver 3, the outer cylinder 2 may be removed.

[0252] Step 15 (

[15] ): The affected area is closed. The wound may be closed after fitting the cap 9 from the head 11 of the internal fixation device 1 to the through-hole 19. By closing the through-hole 19 from the head 11 of the internal fixation device 1 with the cap 9, it is possible to avoid a situation in which the head 11 and the through-hole 19 are blocked by scars or the like, making it impossible to insert the driver 3 or the like, even if it becomes necessary to remove the internal fixation device 1 in the future.

[0253] As described above, the internal fixation device 1, outer cylinder 2, and driver 3 are connected to one another, communicating the through-hole 19 with the through-hole 39, and function as a guide for sequentially introducing the bone drilling inner cylinder 4, bone excavation device 25, balloon catheter 26, cement filling device (cement filling tube 5 and cement pushing rod 6), and cement molding device 7 into the vertebral body 92. Various instruments can be introduced into the vertebral body 92 while the outer cylinder 2 and driver 3 are attached to the internal fixation device 1 without having to be replaced midway, simplifying the procedure.

[0254] [Embodiment 10] The treatment device 10 of the above-described embodiments 1 to 9 may further include a cap 9 that is inserted into the through-hole 19 and the opening of the head portion 11 of the internal fixation device 1. This prevents the head portion of the internal fixation device 1 from being blocked by adhesion with surrounding body tissues, such as a scar, after the internal fixation device 1 is implanted in the patient's body until removal becomes necessary, thereby preventing the internal fixation device 1 from being blocked by adhesion with surrounding body tissues, such as a scar, which would hinder removal.

[0255] 19 is an explanatory diagram schematically illustrating a cross-sectional structure to show an example configuration of the cap 9. The internal fixation device 1 has a cap fixing thread 18 proximal to the fitting portion 13 of the through-hole 19. The cap 9 has a head that closes the opening of the head 11 of the internal fixation device 1 and a shaft that is inserted into the through-hole 19 of the internal fixation device 1, and the shaft is provided with a cap fixing thread 94 that meshes with the cap fixing thread 18. The head of the cap 9 is formed with a socket that is compatible with a tool for screwing it in, such as a hexagonal groove for a hex wrench or a Phillips groove for a Phillips screwdriver.

[0256] In the procedure described in embodiment 3, the step of attaching the cap 9 shown in (A) to the internal fixation device 1 follows step 13 (

[10] in FIG. 22), i.e., before or after removing the outer tube 2. The driver 3 that has screwed the internal fixation device 1 into the bone cement 50 is removed, and the cap 9 is inserted through the through-hole 29 of the outer tube 2 up to the head 11 of the internal fixation device 1, and then turned with an appropriate rotary tool such as a hex wrench or a Phillips head screwdriver to screw the cap 9 onto the cap fixing screw threads 18 of the internal fixation device 1. When the step of attaching the cap 9 to the internal fixation device 1 is added, the through-hole 19 of the internal fixation device 1 is blocked by the cap 9, as shown in [11'] in FIG. 22.

[0257] In the procedure described in embodiment 1, the step of removing the cap 9 shown in (B) from the internal fixation device 1 occurs before or after step 2 ([2] in FIG. 23 ) of the removal procedure for the internal fixation device 1. It is assumed that the cap 9 is attached to the head 11 of the internal fixation device 1. The cap 9 attached to the exposed head 11 of the internal fixation device 1 is turned and removed using an appropriate rotating tool such as a hex wrench or a Phillips head screwdriver before the outer tube 2 is attached to the head of the internal fixation device 1 exposed after retraction in step 2 ([2]), and then the outer tube 2 is attached to the internal fixation device 1, and the procedure proceeds to step 3 and beyond. Alternatively, the outer tube 2 may be attached to the exposed head 11 of the internal fixation device 1, and the cap 9 may be turned and removed by inserting an appropriate rotating tool such as a hex wrench or a Phillips head screwdriver through the through-hole 29 of the attached outer tube 2.

[0258] In the procedure described in embodiment 6, the step of attaching the cap 9 to the internal fixation device 1 follows step 12 (

[10] in Fig. 25), i.e., before or after removing the outer tube 2, and as shown in [11'] in Fig. 25, the through-hole 19 of the internal fixation device 1 is closed by the cap 9. The step of removing the cap 9 from the internal fixation device 1 occurs before or after attaching the outer tube 2 in step 2 ([2] in Fig. 26) of the procedure of removing the internal fixation device 1.

[0259] In the procedure described in embodiment 7, the step of attaching the cap 9 to the internal fixation device 1 follows step 11 ([9] in Fig. 28), i.e., before or after removing the outer tube 2, and as shown in [9'] in Fig. 28, the through-hole 19 of the internal fixation device 1 is closed by the cap 9. The step of removing the cap 9 from the internal fixation device 1 occurs before or after attaching the outer tube 2 in step 2 ([2] in Fig. 26) of the procedure for removing the internal fixation device 1.

[0260] 20 is an explanatory diagram showing a cross-sectional structure of another example of the cap 9. The cap 9 has a thread 74 that mates with a thread groove 73 formed by the formed thread of the cement forming part 72 of the cement forming instrument 7. The head of the cap 9 is formed with a socket suitable for a tool used for screwing it in, such as a hexagonal groove for a hex wrench or a Phillips groove for a Phillips screwdriver.

[0261] The step of attaching the cap 9 shown in (A) to the internal fixation device 1 follows step 13 (

[10] in FIG. 22) in the procedure described in embodiment 3, as in the explanation referring to FIG. 19. The driver 3 that has screwed the internal fixation device 1 into the bone cement 50 is removed, and the cap 9 is introduced through the through-hole 29 of the outer cylinder 2 to the hole formed by the cement molding device 7. The cap 9 is then turned with an appropriate rotary tool such as a hex wrench or a Phillips head screwdriver to screw it into the thread groove 73 formed by the molding thread of the cement molding portion 72.

[0262] 19 , the step of removing the cap 9 shown in (B) from the internal fixation device 1 is performed before or after step 2 ([2] in FIG. 23 ) of the removal procedure of the internal fixation device 1 in the procedure described in embodiment 3. The cap 9 is screwed into the hole formed by the cement molding device 7, and its head is fitted into the head of the internal fixation device 1. Before the outer tube 2 is attached to the internal fixation device 1 exposed after retraction in step 2 ([2]), the head of the cap 9 visible from the exposed head of the internal fixation device 1 is turned using an appropriate rotating tool such as a hex wrench or a Phillips head screwdriver to remove the cap 9. After that, the outer tube 2 is attached to the internal fixation device 1, and the procedure proceeds to step 3 and beyond. Alternatively, the outer tube 2 may be attached to the exposed head of the internal fixation device 1, and then an appropriate rotating tool such as a hex wrench or a Phillips head screwdriver may be inserted through the through-hole 29 of the attached outer tube 2 to turn and remove the cap 9.

[0263] In the procedure described in embodiment 6, the step of attaching the cap 9 to the internal fixation device 1 follows step 12 (

[10] in Fig. 25), i.e., before or after removing the outer tube 2, and as shown in [11'] in Fig. 25, the through-hole 19 of the internal fixation device 1 is closed by the cap 9. The step of removing the cap 9 from the internal fixation device 1 occurs before or after attaching the outer tube 2 in step 2 ([2] in Fig. 26) of the procedure of removing the internal fixation device 1.

[0264] In the procedure described in embodiment 7, the step of attaching the cap 9 to the internal fixation device 1 follows step 11 ([9] in Fig. 28), i.e., before or after removing the outer tube 2, and as shown in [9'] in Fig. 28, the through-hole 19 of the internal fixation device 1 is closed by the cap 9. The step of removing the cap 9 from the internal fixation device 1 occurs before or after attaching the outer tube 2 in step 2 ([2] in Fig. 26) of the procedure for removing the internal fixation device 1.

[0265] Although not shown, the threads 74 of the cap 9 may be the threads of a tapping screw. The cement molding portion 72 of the cement molding instrument 7 is cylindrical, tapered, or conical without molding threads, and the cap 9 is fixed by screwing the threads 74 of the cap 9 into the cement molding portion 72.

[0266] Although the cement molding instrument 7 has been described as an example of an instrument for forming a hole in the bone cement 50, it may also be the cement pushing rod 6 having the cement molding portion 62 at its tip, as described in the fifth embodiment. Alternatively, it may be the tip portion of the bone drilling inner tube 4 integrated with the driver 3 shown in the first to third embodiments. Furthermore, a hole may not be formed in the bone cement 50 beforehand, and a cap 9 having a tapping screw or a normal thread may be screwed onto the tip before the bone cement 50 has hardened. In this case, it is more preferable that the tip of the cap 9 be shaped so that the tip of the cement fixing instrument 8 (see the eighth and ninth embodiments) can fit into the tip of the cap 9 after removal, thereby fixing the bone cement 50 and particularly preventing rotation.

[0267] [Embodiment 11] The treatment instrument 10 of this embodiment 11 is configured to include an internal fixation instrument 1 that is inserted into a vertebral body from the pedicle, an outer cylinder 2, and a cement separating instrument 800, and is equipped with a motion direction conversion mechanism that converts a rotational force that rotates the cement separating instrument 800 around its central axis when the cement separating instrument 800 is inserted into the through-hole 19 of the internal fixation instrument 1 into a linear force that moves the cement separating instrument 800 linearly along the central axis, with the internal fixation instrument 1 or the outer cylinder 2 connected thereto as a fulcrum.

[0268] This makes it possible to provide a treatment instrument 10 that, when removing an internal fixation instrument 1 such as a screw that has been screwed from the pedicle into bone cement filled in the vertebral body during vertebroplasty, can safely separate and remove the internal fixation instrument 1 from the bone cement without damaging the surrounding tissues within the bone, even if the bone cement has not adhered to the surrounding bone and is loosened within the bone.

[0269] Furthermore, it is preferable that the rotation of the cement separation instrument 800 at this time be in the same direction as the direction in which the tapping screw thread 15 is screwed into the bone hole in the pedicle. When the screwing direction of the tapping screw thread 15 is clockwise, rotating the internal fixation instrument 1 counterclockwise, which is the opposite direction to the clockwise screwing direction, applies a rotational force in the direction of removal. When the cement separation instrument 800 is turned clockwise, which is the opposite direction to the counterclockwise rotation of the internal fixation instrument 1, the force is converted into a linear force toward the tip of the internal fixation instrument 1, and both the rotational force and the linear force act to separate the internal fixation instrument 1 from the bone cement 50. Because the outer tube 2 connected to the internal fixation instrument 1 serves as a fulcrum, the surgeon can apply a counterclockwise force to the outer tube 2 connected to the internal fixation instrument 1 to prevent the internal fixation instrument 1 from rotating clockwise together with the cement separation instrument 800. Furthermore, once the internal fixation device 1 is separated from the bone cement 50, the tapping screw thread 15 of the internal fixation device 1 can be removed from the bone hole in the pedicle by turning the outer cylinder 2 counterclockwise, providing good alignment.

[0270] In summary, the connection between the internal fixation device 1 and the outer cylinder 2 does not loosen when the internal fixation device 1 is rotated in the direction of removal, and by applying a rotation to the cement separation device 800 in the opposite direction to the internal fixation device 1, the rotation applied to the cement separation device 800 is converted into a linear force that moves the cement separation device 800 in a straight line, which helps to separate the cement from the bone cement 50 and allows the internal fixation device 1 to be separated and removed more safely.

[0271] The motion direction conversion mechanism typically has a screw structure. By rotating the cement separation instrument 800, the cement separation instrument 800 moves linearly in a direction perpendicular to the rotation axis. The cement separation instrument 800 applies a linear force in the same direction as the insertion direction to separate the internal fixation instrument 1 inserted into the bone cement from the bone cement. Ideally, the fulcrum of this force is located on the internal fixation instrument 1, but it may also be on the outer cylinder 2 connected to the internal fixation instrument 1, or on another instrument connected on the same central axis.

[0272] 30 is an explanatory diagram schematically illustrating a cross-sectional structure to illustrate a configuration example of the treatment instrument 10 of embodiment 11. In this example, a screw structure that functions as a motion direction conversion mechanism is provided inside the through-hole 29 of the outer cylinder 2.

[0273] The cement separating device 800 has a shaft 804 that is inserted into the through-hole 19 of the internal fixation device 1. An outer tube side thread 22 (which may be simply referred to as the "thread 22" when it is clear that it is the thread provided on the outer tube 2) is provided inside the through-hole 29 of the outer tube 2, and the cement separating device 800 has a separation device side thread 802 (which may be simply referred to as the "thread 802" when it is clear that it is the thread provided on the cement separating device 800) on the outer periphery of the shaft 804. The cement separating device 800 is inserted into the communicating through-holes 19 and 29, and the thread structure in which the separation device side thread 802 on the outer periphery of the shaft 804 meshes with the outer tube side thread 22 provided inside the through-hole 29 of the outer tube 2 functions as a motion direction conversion mechanism. In other words, when the cement separating instrument 800 is rotated, the screw structure converts the rotational force into a linear force along the central axis of rotation, which causes the shaft 804 of the cement separating instrument 800 to move linearly toward the tip within the through hole 19 of the internal fixation instrument 1.

[0274] A handle 808 may be provided at the distal end of the cement separation instrument 800. The handle 808 may be welded or glued to the shaft 804, or may be configured to be detachable. The outer cylinder 2 is more preferably provided with the connection mechanism 200 as shown in embodiment 5, particularly a wrench fitting portion 202 near the distal end into which a wrench can be fitted (see the X-Y cross-sectional view in FIG. 30 ). When the cement separation instrument 800 is rotated, the outer cylinder 2 tends to rotate accordingly, but this can be prevented by fitting a wrench into the wrench fitting portion 202.

[0275] FIG. 31 is an explanatory diagram showing an example of the operation of the cement separation instrument 800. The figure shows the internal fixation instrument 1 screwed into a bone hole formed from the pedicle 91 toward the vertebral body 92 using the tapping screw thread 15 formed on the distal side of the shaft 14 of the internal fixation instrument 1. The left side shows the state before removal of the internal fixation instrument 1, and the right side shows the state during removal. The figure is schematic, and the length, size, and shape, including the aspect ratio, are exaggerated or omitted for the purpose of explanation. The distal end portion of the internal fixation instrument 1 is shown enlarged below. Furthermore, the positions of the separation instrument side thread 802 and the outer tube side thread 22, which are the motion direction conversion mechanism, have been changed from those shown in FIG. 30 to positions closer to the internal fixation instrument 1.

[0276] Referring to the left side of FIG. 31 , the tip portion of the internal fixation device 1 is embedded in bone cement 50 in a vertebral body 92. The groove 17 described in the “Details of the Internal Fixation Device” section of the third embodiment is formed at the tip of the internal fixation device 1, and bone cement 50 fills the groove 17. The groove 17 may be a spiral groove, a concentric groove, or an island-shaped recess. The internal fixation device 1 and the outer tube 2 are connected by connecting portions 12 and 21, and through-holes 19 and 29 (not shown in the figure) communicate with each other. The cement separation device 800 is configured so that, when inserted through the through-holes 19 and 29 that communicate with each other when the internal fixation device 1 and the outer tube 2 are connected, the separation device-side thread 802 engages with the thread 22 provided on the through-hole 29 of the outer tube 2. However, in the left-hand view, the separation device-side thread 802 has not yet reached the position where it engages with the outer tube-side thread 22.

[0277] The right side of Fig. 31 shows a state in which the threads 802 of the cement separation instrument 800 are screwed into the outer tube threads 22. When the cement separation instrument 800 is rotated from the state shown on the left side of Fig. 31 , it is linearly pushed proximally along the central axis, and the tip of the cement separation instrument 800 advances linearly through the through-hole 19 of the internal fixation instrument 1 and even protrudes from the tip, applying a linear pushing force to the bone cement 50. This force separates the internal fixation instrument 1 from the bone cement 50. If part of the bone cement 50 has entered the through-hole 19 of the internal fixation instrument 1, that part of the bone cement 50 is pushed out and separated. Alternatively, although not shown, the bone cement in the through-hole 19 of the internal fixation instrument 1 may be removed in advance to the state shown in the figure by scraping it out with a sharp drill large enough to insert into the through-hole.

[0278] At this time, the internal fixation device 1 is removed while also destroying the bone cement 50 that has entered the groove 17 or recess at the tip of the internal fixation device 1. As shown in the enlarged view at the bottom left of Fig. 31 , the bone cement 50 has entered and hardened in the groove 17 at the tip of the internal fixation device 1, preventing the bone cement 50 from dislodging. However, by separating the internal fixation device 1 with a linear force, the portion that has entered the groove 17 is destroyed and separated from the main body of the bone cement 50, as shown in the enlarged view at the bottom right of Fig. 31 . In the drawing, the internal fixation device 1 is pushed distally (toward the back) in a linear direction during separation. However, depending on the loosening state of the internal fixation device 1, the pedicle 91, and the surrounding bone cement 50, the bone cement 50 may be pushed forward toward the anterior side of the vertebral body and separated (not shown). After the bone cement 50 has been separated from the internal fixation device 1, the cement separation device 800 is temporarily removed. A driver (not shown; for example, the driver 3 in the second embodiment) that engages with the head of the internal fixation device 1 is inserted into the through-hole 29 of the outer tube 2 and engaged with the head 11 of the internal fixation device 1. A rotational force is then applied to the internal fixation device 1 in the removal direction, thereby removing the internal fixation device 1 without resistance from the spine. Alternatively, the internal fixation device 1 may be removed by rotating it using the connected outer tube 2 in the direction opposite to the direction in which the tapping screw threads 15 were screwed into the pedicle 91, thereby using not only the linear force of the cement separation device 800 but also a rotational force. On the other hand, when the internal fixation device 1 is removed using only a linear force without using a rotational force, the tapping groove formed in the bone tunnel in the pedicle 91 is destroyed during removal.

[0279] When a hole shaped to a predetermined shape is formed in the bone cement 50 at the tip of the internal fixation device 1 by the cement shaping portion 62 of the cement pushing rod 6 described in the eighth embodiment or the cement shaping portion 72 at the tip of the cement shaping device 7 described in the ninth embodiment, the tip of the cement separating device 800 may be shaped to fit into the hole. Since rotational force and linear force can be applied to the bone cement 50, the rotational force of the cement separating device 800 can be transmitted to the bone cement 50 more effectively.

[0280] Alternatively, the tip of the cement separating instrument 800 may be a conical or hemispherical protrusion with a tapping screw thread. Figures 32 and 33 are enlarged views showing examples of the configuration of the tip portion of the cement separating instrument 800. As shown in Figure 32, the tip portion 801 of the cement separating instrument 800 includes a truncated conical region on which a helical thread is formed and a conical end portion at the tip. The truncated cone on which the helical thread is formed is inclined, for example, at ±10° around the central axis, for a total of 20°, and the end portion is inclined at ±45°, for a total of 90°. Figure 33 shows the tip portion 801 of another cement separating instrument 800, including a truncated conical region on which a helical thread is formed and a spherical portion at the tip. The truncated cone on which the helical thread is formed is inclined, for example, at ±5° around the central axis, for a total of 10°, and the end portion is hemispherical. By making the end portion hemispherical, it is possible to reduce the risk of damaging the bone cement 50 when pushing to separate the bone cement 50 from the internal fixation device 1. Note that Figures 32 and 33 are merely examples, and the shape, angle, and size can be changed as appropriate.

[0281] [Procedure for surgical procedure to remove the internal fixation device] FIG. 34 is an explanatory diagram showing an example of a procedure for surgical procedure to remove the internal fixation device 1 using the treatment device 10 of the eleventh embodiment.

[0282] Step 1 ([1]): The skin is incised to expose the head 11 of the internal fixation device 1 through the wound incision 93.

[0283] Step 2 ([2]): Connect the outer tube 2 to the head 11 of the internal fixation device 1. At this time, if the tapping screw threads 15 on the outer periphery of the internal fixation device 1 are screwed clockwise into the pedicle 91 and fixed, and the connection parts 12 and 21 have threads formed in the opposite direction, turn the outer tube 2 counterclockwise to connect it to the head 11 of the internal fixation device 1. If the internal fixation device 1 can be removed by turning the connected outer tube 2 in the opposite direction (counterclockwise) to the direction in which the internal fixation device 1 was screwed in, remove it as is, and proceed to closure in Step 6 ([6]) without performing the subsequent steps.

[0284] Step 3 ([3]): The cement separating instrument 800 is inserted into the through-hole (the through-hole where the first through-hole 19 and the second through-hole 29 communicate) formed by connecting the internal fixation instrument 1 and the outer cylinder 2. Although not shown, if the through-hole 19 of the internal fixation instrument 1 is blocked with bone cement, bone fragments, scars, or other foreign matter, the foreign matter may be excavated and removed from the through-hole 19 of the internal fixation instrument 1 in advance using a drill or the like, thereby making it possible to pass the cement separating instrument 800 through the through-hole.

[0285] Step 4 ([4]): The inserted cement separation instrument 800 is rotated to screw the threads 802 into the threads 22 of the outer cylinder 2, and the tip of the cement separation instrument 800 is advanced into the through-hole 19 of the internal fixation instrument 1. By advancing it further, the tip of the cement separation instrument 800 comes into contact with the bone cement 50. By further rotating the cement separation instrument 800 and advancing it deeper, the internal fixation instrument 1 is separated from the bone cement 50. The outer cylinder 2 connected to the internal fixation instrument 1 is rotated and pulled out, but if the tapping threads of the pedicle are not strong, it may be pulled out linearly while destroying the inner wall of the pedicle bone tunnel. At this time, if the adhesion between the bone cement 50 and the internal fixation device 1 is strong, but the fusion between the bone cement 50 and the inner wall of the vertebral body 92 is loose and the bone cement 50 is prone to freewheeling, as shown in the inset (top view) in Figure 34 [4], a wrench 299 can be fitted into the wrench fitting portion 202 provided on the outer periphery of the outer tube 2 to prevent the internal fixation device 1 and outer tube 2 from rotating together with the cement separating device 800.

[0286] Step 5 ([5]): The internal fixation device 1 is removed while the outer tube 2 and the cement separating device 800 remain connected. Although not shown in the drawings, after the internal fixation device 1 is separated from the bone cement 50, the cement separating device 800 can be temporarily removed, and a driver or the like (for example, the driver 3 described later in embodiment 13) that engages with the head of the internal fixation device 1 can be inserted through the through-hole 29 of the outer tube 2 and engaged with the head of the internal fixation device 1. A rotational force in the removal direction can then be applied to the internal fixation device 1, thereby removing the internal fixation device 1 from the pedicle.

[0287] Step 6 ([6]): The wound opening 93 is sutured and closed.

[0288] As described above, the cement separating tool 800 of the eleventh embodiment is pushed out from the internal fixation tool 1 using the outer tube 2 connected to the internal fixation tool 1 as a fulcrum. This allows the internal fixation tool 1 to be separated from the bone cement 50 and removed without being affected by the strength of adhesion (adhesion) between the bone cement 50 and the surrounding body tissues. If it is necessary to remove the bone cement 50 from the vertebral body 92, after removing the internal fixation tool 1 in step 5 ([5]), another skin incision is used to approach the anterior and lateral sides of the vertebral body, and the bone cement 50 is removed from the anterior and lateral sides. In steps 3 and 4 ([3] to [4]), the bone cement 50 is separated from the internal fixation tool 1 by a linear force using the outer tube 2 connected to the internal fixation tool 1 as a fulcrum. Therefore, the separating force acts only between the internal fixation tool 1 and the bone cement 50. By having the surgeon hold the outer tube 2 connected to the internal fixation tool 1, the risk of the internal fixation tool 1 being moved by a strong force in the direction of removal within the vertebral body 92 is reduced.

[0289] Figure 35 is an explanatory diagram showing another example of the procedure for the surgical procedure for removing the internal fixation device 1 using the treatment device 10 of this embodiment 11. Steps 1 and 2 ([1] and [2]) are the same as those in the example described above with reference to Figure 34, but step 3 ([3]) and subsequent steps are different. In the example of Figure 34, the internal fixation device 1 is pushed distally (toward the back) in a straight line during separation. However, depending on the loosening state of the internal fixation device 1 and the surrounding bone cement 50, the internal fixation device 1 may remain in position, and the bone cement 50 may be pushed forward toward the anterior vertebral body and separated (Figure 35 [3]). That is, step 3 ([3]) and subsequent steps are as follows.

[0290] Step 3 ([3]): The cement separating instrument 800 is inserted into the through-hole (the through-hole where the first through-hole 19 and the second through-hole 29 are connected) formed by connecting the internal fixation instrument 1 and the outer cylinder 2. When the cement separating instrument 800 is rotated while the outer cylinder 2 is used to prevent the rotation of the internal fixation instrument 1, the tip of the cement separating instrument 800 protrudes from the tip of the internal fixation instrument 1 and pushes the bone cement 50, separating it and pushing it forward from the vertebral body 92 (the opposite side from the pedicle 91). At this time, if the adhesion between the bone cement 50 and the internal fixation instrument 1 is strong but the fusion between the bone cement 50 and the inner wall of the vertebral body 92 is loose and the bone cement 50 is prone to freewheeling, as shown in the inset (top view) in Figure 35 [3] as in Figure 34 [4], a wrench 299 can be fitted into the wrench fitting portion 202 provided on the outer periphery of the outer cylinder 2 to prevent the internal fixation instrument 1 and the outer cylinder 2 from rotating together with the cement separating instrument 800.

[0291] Step 4 ([4]): Remove the cement separation instrument 800.

[0292] Step 5 ([5]): The outer cylinder 2 is rotated to remove the internal fixation device 1 from the pedicle 91.

[0293] Step 6 ([6]): The wound opening 93 is sutured and closed.

[0294] In steps 4 and 5 ([4] to [5]), the cement separating instrument 800 may not be removed first, but may be removed integrally with the outer tube 2 and the internal fixation instrument 1 while they remain connected.

[0295] [Embodiment 12] In the treatment instrument 10 of embodiment 11, the motion direction conversion mechanism is configured by a screw structure provided on the outer tube 2 and the cement separation instrument 800, i.e., the outer tube side thread 22 and the separation instrument side thread 802, but it can also be configured by a screw structure provided on the internal fixation instrument 1 and the cement separation instrument 800, i.e., the internal fixation instrument side thread 18 and the separation instrument side thread 802.

[0296] 36 is an explanatory diagram schematically illustrating a cross-sectional structure to illustrate a configuration example of the treatment instrument 10 of embodiment 12. A shaft 804 of the cement separation instrument 800 has a separation instrument-side thread 802 on its outer periphery, and the motion direction conversion mechanism is formed by the engagement of the separation instrument-side thread 802 with the internal fixation instrument-side thread 18 formed in the through-hole 19 of the internal fixation instrument 1. This allows the fulcrum of the linear force that moves the cement separation instrument 800 linearly to be set within the internal fixation instrument 1, allowing the internal fixation instrument 1 to be safely separated and removed from the bone cement 50. When the internal fixation instrument 1 and the bone cement 50 are strongly fixed, a large force is required for separation. However, the internal fixation instrument 1 to be separated itself serves as the fulcrum, allowing a force that linearly separates the internal fixation instrument 1 and the bone cement 50 to be directly applied. As in the eleventh embodiment shown in Fig. 30, the outer cylinder 2 is preferably provided with the connection mechanism 200 as shown in the fifth embodiment, particularly with a wrench fitting portion 202 near the distal end into which a wrench can be fitted (see the X-Y cross-sectional view in Fig. 36). When the cement separation instrument 800 is rotated, the outer cylinder 2 tends to rotate accordingly, but this can be prevented by fitting a wrench into the wrench fitting portion 202.

[0297] As in the eleventh embodiment, when the internal fixation device 1 has a tapping thread 15 on its outer periphery and the thread structure connecting the internal fixation device 1 and the outer tube 2 is threaded in the opposite direction to the tapping thread 15 provided on the outer periphery of the internal fixation device 1, it is preferable that the thread structure formed by the internal fixation device-side thread 18 and the separation device-side thread 802 be threaded in the same direction as the tapping thread 15. For example, when the screwing direction of the tapping thread 15 of the internal fixation device 1 is clockwise, a rotational force in the removal direction is applied by rotating the outer tube 2 counterclockwise, which is the opposite direction to the clockwise direction in which the internal fixation device 1 rotates, and when the cement separation device 800 is turned clockwise, which is the opposite direction to the counterclockwise direction in which the internal fixation device 1 rotates, the rotational force is converted into a force that moves linearly toward the tip of the internal fixation device 1, and both the rotational force and the linear force act to separate the internal fixation device 1 from the bone cement 50.

[0298] Furthermore, even if the internal fixation device 1 does not have the self-tapping threads 15 on its outer periphery and is linearly inserted into the bone hole in the pedicle, or even if the self-tapping threads 15 are present but the bone hole in the pedicle is not strong enough to remove the internal fixation device 1 without rotating it, the thread structure formed by the internal fixation device-side threads 18 and the separation device-side threads 802 should be in the opposite direction to the thread structure connecting the internal fixation device 1 and the outer tube 2. When separating the internal fixation device 1, it is necessary to prevent the internal fixation device 1 from rotating with a force in the opposite direction to the direction in which the cement separation device 800 is rotated, and therefore, even if the outer tube 2 is connected to the internal fixation device 1 at that time, the direction in which the connection will not loosen will be the direction in which the connection will not loosen.

[0299] The cement separation instrument 800 preferably has a tip portion 801 that protrudes from the tip of the internal fixation instrument 1 when the separation instrument-side threads 802 are screwed into the internal fixation instrument-side threads 18. When the cement separation instrument 800 protrudes from the tip of the internal fixation instrument 1, it pushes the bone cement 50 at the tip of the internal fixation instrument 1, assisting in separation. On the other hand, if the proximal side of the through-hole 19 of the internal fixation instrument 1 is filled with bone cement 50, the cement separation instrument 800 does not necessarily have to be long enough to protrude from the tip of the internal fixation instrument 1. Furthermore, although not shown, even if the through-hole 19 of the internal fixation instrument 1 is blocked with bone cement, bone fragments, scars, or other foreign matter, the cement separation instrument 800 can be inserted into the through-hole 19 by previously drilling and removing the foreign matter from the through-hole 19 of the internal fixation instrument 1.

[0300] Similar to the case of the 10th embodiment, the treatment instruments 10 of the 11th and 12th embodiments are more preferably configured to further include a cap 9 that is inserted into the opening of the head 11 of the internal fixation device 1. This makes it possible to prevent the head 11 of the internal fixation device 1 and the through-hole 19 from being blocked by bone cement, bone fragments, scar tissue, or other foreign matter.

[0301] The cap 9 may include not only the head 11 of the internal fixation device 1 but also a shaft 94 to be inserted into the through-hole 19. The shaft 94 may be provided on its outer periphery with a cap fixing thread 98 that engages with the above-mentioned internal fixation device thread 18. In surgery to insert the internal fixation device 1 into bone cement 50 in a vertebral body from the pedicle, fitting the cap 9 after inserting the internal fixation device 1 reduces the risk of bone cement, bone fragments, or other foreign matter getting in and causing eschar, and also reduces the risk of the cap 9 coming off after surgery.

[0302] FIG. 37 is an explanatory diagram showing an example configuration of the cap 9. Two types are shown: (A) for embodiment 11 and (B) for embodiment 12. The cap 9 is configured to be inserted into the opening of the head 11 of the internal fixation device 1 to close the opening. The cap 9 is more likely to be stable in the inserted state if it has a shaft 94 that is inserted into the through-hole 19 of the internal fixation device 1. As shown in (B), when the internal fixation device 1 is formed with threads 18 that engage with the threads 802 of the cement separation device 800, the shaft 94 may further be formed with cap-fixing threads 98 on the outer periphery to engage with the threads 18 of the internal fixation device 1. Screwing the cap 9 can significantly reduce the risk of it coming off after surgery. In this case, it is preferable that the head of the cap 9 be formed with a groove that can fit a Phillips or flathead screwdriver, a hex wrench, or the like, so that the cap 9 can be attached or removed by screwing the cap-fixing threads 98 into the threads 18 of the internal fixation device 1.

[0303] The head of the cap 9 can be sized to tightly close the opening of the head 11 of the internal fixation device 1, or a gap large enough to allow the connection portion 21 of the outer tube 2 to be connected to the connection portion 12 may be left. If the head 11 of the internal fixation device 1 has an engaging portion 13 for a driver 3 (not shown) used to screw the internal fixation device 1 into the bone cement 50, it is advisable to close this portion. There is an option to use the driver 3 when removing the internal fixation device 1, and in that case, this can prevent the engaging portion 13 from being blocked by scar tissue or the like.

[0304] FIG. 38 is an explanatory diagram showing another configuration example of the cap 9. Two types are shown: (A) for Embodiment 11 and (B) for Embodiment 12. In (A), the cap 9 does not have a cap fixing thread 98 that engages with the thread 18 of the internal fixation device 1. However, in (B), the internal fixation device 1 has a thread 18 that engages with the thread 802 of the cement separation device 800, and the cap fixing thread 98 is formed on the outer periphery of the shaft 94 of the cap 9 so as to engage with the thread 18 of the internal fixation device 1. The cap 9 in FIG. 37 is fixed to the internal fixation device 1, but in FIG. 38, instead of or in addition to this, it is configured to be fixed to bone cement 50. The shaft 94 of the cap 9 has a tip portion 99 that protrudes from the tip of the internal fixation device 1 when the cap 9 is attached to the internal fixation device 1. The tip portion 99 may be formed with a screw thread, a tapping screw thread, or a screw groove to be embedded in the bone cement 50, or may be formed with a simple island-shaped or ring-shaped convex or concave portion, or may be flat without any concave or convex portions. Furthermore, as will be described in a thirteenth embodiment below, when a cement molding instrument 7 is protruded from the tip of the internal fixation instrument 1 inserted into the bone cement 50 to form a hole in the bone cement 50 and mold it into a predetermined shape, the tip portion 99 of the cap 9 may also be formed to fit into the hole.

[0305] The timing for inserting the cap 9 in the surgical procedure for implanting the internal fixation device 1 may be after the internal fixation device 1 has been screwed into the bone cement 50 injected into the vertebral body with a screwdriver, or it may be inserted at the same time as inserting the internal fixation device 1 into the bone cement 50. In this case, an improved screwdriver 3 can be used so that the cap 9 can be rotated together with the internal fixation device 1 in a fitted state.

[0306] FIG. 39 is a cross-sectional view showing an example of the configuration of the connection portion of the improved driver 3 with the internal fixation device 1 and the cap 9. The upper side shows a front cross-section, and the lower side shows its X-X' cross-section. The improved driver 3 includes a fitting portion 33 that fits into the fitting portion 13 of the head 11 of the internal fixation device 1, as well as a cap driver 35 that rotates the cap 9. As shown in FIG. 39, the fitting portions 33 and 13 of the improved driver 3 and the internal fixation device 1 can be fitted with, for example, a hex wrench, and the cap driver 35 can be configured, for example, as a Phillips head screwdriver that fits into a Phillips head screwdriver groove formed in the head of the cap 9 to rotate the cap 9. When the fitting portions 33 and 13 of the improved driver 3 and the internal fixation device 1 are fitted together, the Phillips head screwdriver that is the cap driver 35 fits into the Phillips head screwdriver groove in the head of the cap 9. The rotation of the improved driver 3 is transmitted to the cap 9 as well as the internal fixation device 1. The shapes of the fitting portions 33 and 13 and the cap driver 35 may be any shape as long as they are configured to fit together and transmit a rotational force, and may be, for example, a star shape, a cross shape, a flathead screwdriver shape, etc. Using this improved driver 3, the cap driver 35 is fitted into the cap 9 inserted into the internal fixation device 1, and further fitted into the fitting portion 33 of the fitting portion 13 of the head 11 of the internal fixation device 1, thereby rotating the cap 9 and the internal fixation device 1 together and screwing them into the bone cement 50.

[0307] [Procedure for surgical procedure to remove the internal fixation device] FIG. 40 is an explanatory diagram showing the procedure for surgical procedure to remove the internal fixation device 1 using the treatment device 10 of the twelfth embodiment.

[0308] Step 1 ([1]): The skin is incised to expose the head 11 of the internal fixation device 1 from the wound incision 93. At this time, the head of the cap 9 attached to the internal fixation device 1 is also exposed.

[0309] Step 2 ([2]): Remove the cap 9 from the internal fixation device 1. If it is fastened with a screw as in the examples shown in Figures 33 and 34, loosen the screw and remove the cap. Before or after removing the cap 9, connect the outer tube 2 to the head 11 of the internal fixation device 1.

[0310] Step 3 ([3]): The cement separating instrument 800 is inserted into the through-hole 19 of the internal fixation instrument 1 and the through-hole 29 of the outer cylinder 2. The threads 802 of the cement separating instrument 800 are engaged with the internal fixation instrument side threads 18 provided in the through-hole 19 of the internal fixation instrument 1.

[0311] Step 4 ([4]): The inserted cement separation instrument 800 is rotated to screw the threads 802 into the threads 18 of the internal fixation instrument 1, and the tip of the cement separation instrument 800 is advanced into the through-hole 19. By advancing it further, the tip of the cement separation instrument 800 comes into contact with the bone cement 50. By further rotating the cement separation instrument 800 and advancing it deeper, the internal fixation instrument 1 is separated from the bone cement 50. When rotating the cement separation instrument 800, the surgeon may apply force to the outer cylinder 2 to prevent the internal fixation instrument 1 from rotating in the same direction as the cement separation instrument 800, or may actively rotate the outer cylinder 2 in the opposite direction to the rotation of the cement separation instrument 800 to apply a rotational force that removes the internal fixation instrument 1 from the pedicle 91 and the bone cement 50. At this time, if the adhesion between the bone cement 50 and the internal fixation device 1 is strong, but the fusion between the bone cement 50 and the inner wall of the vertebral body 92 is loose and the bone cement 50 is prone to freewheeling, as shown in the inset (top view) in Figure 40 [4] as well as Figure 34 [4] and Figure 35 [3], a wrench 299 can be fitted into the wrench fitting portion 202 provided on the outer periphery of the outer tube 2 to prevent the internal fixation device 1 and outer tube 2 from rotating together with the cement separating device 800.

[0312] Step 5 ([5]): With the cement separation instrument 800 still connected, remove the internal fixation instrument 1. Although not shown in the drawings, after the internal fixation instrument 1 has been separated from the bone cement 50, the cement separation instrument 800 may be removed, a driver 3 may be inserted and engaged with the head 11 of the internal fixation instrument 1, and the internal fixation instrument 1 may be removed from the spine by rotating the tapping screw threads 15 of the internal fixation instrument 1 in the removal direction using the driver 3.

[0313] Step 6 ([6]): The wound opening 93 is sutured and closed.

[0314] As described above, the cement separating tool 800 of the twelfth embodiment is pushed out with the internal fixation tool 1 as a fulcrum, and therefore, the internal fixation tool 1 can be separated from the bone cement 50 and removed without being affected by the strength of adhesion (adhesion) between the bone cement 50 and the surrounding body tissues of the internal fixation tool 1. In the twelfth embodiment, as in the eleventh embodiment, if it is necessary to remove the bone cement 50 from the vertebral body 92, this is done after the removal of the internal fixation tool 1 in step 5 ([5]). In steps 3 and 4 ([3] to [4]), the bone cement 50 is separated from the internal fixation tool 1 by a linear force with the internal fixation tool 1 as a fulcrum. Therefore, the separating force acts only between the internal fixation tool 1 and the bone cement 50, and the risk of damaging the bones, spinal nerves, nerve roots, etc. around the internal fixation tool or bone cement when removing the internal fixation tool from the vertebral body 92 is reduced.

[0315] [Embodiment 13] The treatment instrument 10 including the cement separating instrument 800 of embodiment 11 or 12 may further include a driver 3, and the cement filling tube 5 and cement pushing rod 6 described in embodiment 8, or the cement molding instrument 7 described in embodiment 9.

[0316] The cement pushing rod 6 of the eighth embodiment has a cement shaping part 62 that is inserted into the bone cement 50 from the tip of the internal fixation instrument 1 to form a hole and mold the hole into a predetermined shape, and the cement molding instrument 7 of the ninth embodiment also has a cement shaping part 72 that is inserted into the bone cement 50 from the tip of the internal fixation instrument 1 to form a hole and mold the hole into a predetermined shape. The cement separating instrument 800 of the thirteenth embodiment is configured so that its tip 801 fits into the hole in the molded bone cement 50. That is, the tip 801 of the cement separating instrument 800 is inserted into the hole formed by the cement shaping part 72 of the cement molding instrument 7 in the bone cement mass injected into the vertebral body by the cement filling instruments (5, 6).

[0317] The cement molding portion 72 of the cement molding instrument 7 may be, for example, a triangular, quadrangular, hexagonal, or other rectangular prism, a flat plate with a straight or cross-shaped cross section, or a combination thereof, and the distal end 801 of the cement separating instrument 800 may be shaped to fit into a hole formed by the cement molding portion 72, thereby preventing the bone cement mass from rotating within the vertebral body. Alternatively, the cement molding portion 72 of the cement molding instrument 7 may be, for example, a hemispherical, cylindrical, conical, or truncated conical shape with a circular cross section, and may be formed with a screw thread or thread groove.

[0318] FIG. 41 is an explanatory diagram showing an example of the configuration of the tip portions of the cement molding instrument 7 and the cement separating instrument 800. The cement molding portion 72 at the tip of the cement molding instrument 7 and the tip portion 801 of the cement separating instrument 800 are shown protruding from the tip of the internal fixation instrument 1. The same applies to the cement molding portion 62 at the tip of the cement pushing rod 6. A spiral groove 17 may be formed in the tip portion of the internal fixation instrument 1. A spiral ridge may be used instead of a groove. Alternatively, as described in "Details of the Internal Fixation Instrument," a concentric groove or an island-shaped recess may be formed. This allows the fixation strength of the internal fixation instrument 1 to be adjusted by taking into account the balance between the risk of bone cement mass dislodging and the strength of removal.

[0319] Although FIG. 41 illustrates the thread formed on the distal end 801 of the cement separation instrument 800 with the same lead as the spiral groove 17 formed in the distal portion of the internal fixation instrument 1, the lead may be different. The spiral groove 17 of the internal fixation instrument 1 is often formed with the same lead as not only the tapping thread 15 (not shown in FIG. 41 ) provided on the distal side, but also the thread 802 provided on the outer periphery of the shaft 804 of the cement separation instrument 800. When a large force is required to extrude the bone cement, it is important to transmit a larger driving force to the distal end of the cement separation instrument 800 for a given torque value applied when rotating the cement separation instrument 800 by setting the lead of the thread 802 provided on the outer periphery of the shaft 804 of the cement separation instrument 800 finer. Accordingly, the lead of the spiral groove 17 of the internal fixation instrument 1 is also set finer. The shape of the tapping thread at the tip 801 of the cement separating instrument 800 may be larger than the lead of the separator side thread 802, as long as it can apply a force to grip and rotate the bone cement in addition to the driving force to push the bone cement.

[0320] In the example A in the upper row, the cement molding portion 72 of the cement molding instrument 7 and the tip portion 801 of the cement separating instrument 800 are both truncated cones of the same size, with a spiral thread formed around the periphery.

[0321] In the example B in the middle row, the cement molding portion 72 of the cement molding instrument 7 and the tip 801 of the cement separating instrument 800 are both truncated cones of the same size, and are also formed with a spiral thread around their periphery, just like in example A. The thread of example A is chevron-shaped when viewed in a cross section perpendicular to the direction of rotation and advancement, but the thread of example B is trapezoidal when viewed in a cross section perpendicular to the direction of rotation and advancement.

[0322] In the example C in the lower row, the cement molding portion 72 of the cement molding instrument 7 and the tip portion 801 of the cement separating instrument 800 are both truncated cones of the same size, but differ in whether they have a thread or not. The cement molding portion 72 of the cement molding instrument 7 does not have a thread formed around its periphery, but the tip portion 801 of the cement separating instrument 800 has a self-tapping thread formed around its periphery. The hole formed in the cement molding portion 72 of the cement molding instrument 7 is circular in plan view, and rotation cannot be prevented. By providing the tip portion 801 of the cement separating instrument 800 with a self-tapping thread, rotation of the bone cement mass can be prevented.

[0323] Although examples of combinations of cement molding tools have been shown, these are merely examples, and any combination including sizes and shapes may be used.

[0324] [Embodiment 14] The outer cylinder 2 of Embodiment 12 described with reference to Figure 36 can be replaced by a driver 3 of this embodiment 14. The driver 3 has a shaft 34, a fitting portion 33 that fits with the fitting portion 13 of the internal fixation device 1, and a through-hole 39 that communicates with the through-hole 19 of the internal fixation device 1 when fitted. A handle 38 may be provided at the distal end. The fitting portions 13 and 33 have a relationship similar to that of a regular hexagonal groove and a regular hexagonal prism of a hexagonal wrench, for example, and the rotation of the driver 3 can be transmitted to the internal fixation device 1 by fitting them together.

[0325] 42 is an explanatory diagram schematically illustrating the cross-sectional structure of the treatment instrument of Embodiment 14. As in Embodiment 12, the shaft 804 of the cement separation instrument 800 has a separation instrument-side thread 802 on its outer periphery, and the motion direction conversion mechanism is configured by the engagement of the separation instrument-side thread 802 with the internal fixation instrument-side thread 18 formed in the through-hole 19 of the internal fixation instrument 1. This allows the fulcrum of the linear force that moves the cement separation instrument 800 linearly to be set within the internal fixation instrument 1, allowing the internal fixation instrument 1 to be safely separated and removed from the bone cement 50. When the internal fixation instrument 1 or the bone cement 50 is strongly adhered, a large force is required for separation. However, the internal fixation instrument 1 itself to be separated serves as the fulcrum, allowing a force that linearly separates the internal fixation instrument 1 and the bone cement 50 to be directly applied. The structure of the cement separation instrument 800 is similar to that of the cement separation instrument 800 exemplified in Embodiment 12. Although not shown in the figures, in addition to or instead of the handle 38 of the driver 3, a wrench fitting similar to the wrench fitting 202 attached to the outer periphery of the outer tube 2 in Figures 30 and 36 may be provided on the outer periphery of the driver 3.

[0326] The driver 3 of this embodiment 14 has a shaft 34 and a through-hole 39 corresponding to the shaft 24 and through-hole 29 of the outer tube 2, respectively. The driver 3 has a fitting portion 33 at its proximal end that connects to the fitting portion 13 of the head 11 of the internal fixation device 1, which corresponds to the connecting portion 21 of the outer tube 2. When inserted linearly along the central axis, the fitting portions 13 and 33 fit together and connect. This allows the cement separation device 800 to be rotated to protrude from the tip of the internal fixation device 1 and prevent rotation of the internal fixation device 1 when separating the bone cement. Furthermore, the internal fixation device 1 can be removed from the pedicle into which it has been screwed by rotating the internal fixation device 1 in the opposite direction to the screwing of the tapping screw threads 15. Unlike the connection between the outer tube 2 and the internal fixation device 1, the connection between the driver 3 and the internal fixation device 1 is not linear along the central axis. However, after the driver 3 is released from the pedicle, the connected internal fixation device 1 can be easily removed by pulling the cement separation device 800 linearly.

[0327] As described above, the instrument described as the outer tube 2 in embodiment 12 can be replaced by another instrument (for example, driver 3 in this embodiment 14) that has components corresponding to the shaft 24, through hole 29, and connecting portion 21.

[0328] Similar to the 12th embodiment, the treatment instrument 10 of the 14th embodiment is more preferably configured to further include a cap 9 that is inserted into the opening of the head 11 of the internal fixation instrument 1. This makes it possible to prevent the head 11 of the internal fixation instrument 1 and the through-hole 19 from being blocked by bone cement, bone fragments, scar tissue, or other foreign matter. A detailed description will be omitted.

[0329] [Procedure for surgical procedure for removing the internal fixation device] FIG. 43 is an explanatory diagram showing an example of the procedure for surgical procedure for removing the internal fixation device 1 using the treatment device 10 of the fourteenth embodiment.

[0330] Step 1 ([1]): The skin is incised, and the head 11 of the internal fixation device 1 is exposed from the wound incision 93. At this time, if a cap 9 is attached to the internal fixation device 1, the head of the internal fixation device 1 is also exposed, and the cap 9 is removed from the internal fixation device 1 in the same manner as in the other embodiments.

[0331] Step 2 ([2]): The fitting portion 33 at the tip of the driver 3 is fitted into and connected to the fitting portion 13 at the head of the internal fixation device 1. Although not shown in the figure, a guide pin may be inserted into the through-hole 19 of the internal fixation device 1, and the through-hole 39 of the driver 3 may be introduced along the guide pin, thereby guiding the fitting portion 33 into the fitting portion 13 at the head of the internal fixation device 1.

[0332] Step 3 ([3]): Since the through-hole 19 of the internal fixation device 1 and the through-hole 39 of the driver 3 are connected to each other, the cement separating device 800 is inserted into the connected through-holes 19 and 39, and the threads 802 of the cement separating device 800 are engaged with the internal fixation device-side threads 18 provided in the through-hole 19 of the internal fixation device 1. At this time, the driver 3, instead of the outer cylinder 2, functions as a guide to guide the cement separating device 800 to the internal fixation device 1.

[0333] Step 4 ([4]): The inserted cement separation instrument 800 is rotated to screw the threads 802 into the internal fixation instrument-side threads 18 of the internal fixation instrument 1, and the tip of the cement separation instrument 800 is advanced into the through-hole 19. By advancing it further, the tip of the cement separation instrument 800 comes into contact with the bone cement 50. By further rotating the cement separation instrument 800 to advance it deeper, the internal fixation instrument 1 is separated from the bone cement 50. When rotating the cement separation instrument 800, the surgeon may apply force to the driver 3 to prevent the internal fixation instrument 1 from rotating in the same direction as the cement separation instrument 800, or may actively rotate the driver 3 in the opposite direction to the rotation of the cement separation instrument 800 to apply a rotational force that removes the internal fixation instrument 1 from the pedicle 91 and the bone cement 50.

[0334] Step 5 ([5]): With the cement separation instrument 800 still connected, the internal fixation instrument 1 is removed.

[0335] Step 6 ([6]): The wound opening 93 is sutured and closed.

[0336] As described above, the cement separating tool 800 of the present invention is pushed out using the internal fixation tool 1 as a fulcrum, and therefore can separate and remove the internal fixation tool 1 from the bone cement 50 without being affected by the strength of adhesion (adhesion) between the bone cement 50 and the surrounding body tissues of the bone cement 50 or the internal fixation tool 1. In this embodiment 13, as in embodiments 10 and 2, if it is necessary to remove the bone cement 50 from the vertebral body 92, this is done after removing the internal fixation tool 1 in step 5 ([5]). Since the bone cement 50 is separated from the internal fixation tool 1 by a linear force using the internal fixation tool 1 as a fulcrum in steps 3 and 4 ([3] to [4]), the separating force acts only between the internal fixation tool 1 and the bone cement 50, and the risk of damaging the bones, spinal nerves, nerve roots, etc. around the internal fixation tool or bone cement when removing the internal fixation tool from the vertebral body 92 is reduced.

[0337] While the invention made by the present inventor has been specifically described above based on the embodiments, the present invention is not limited thereto and, needless to say, various modifications are possible without departing from the spirit and scope of the invention. For example, in the thirteenth embodiment, instead of the cement molding instrument 7, the tip of the cement pushing rod 6 of the cement filling instrument may be configured to protrude from the filling tube, and this portion may serve as the cement molding part 62 that forms a hole in the bone cement 50 at the tip of the internal fixation instrument 1 and molds it into a predetermined shape. Alternatively, instead of the cement molding instrument 7, when the internal fixation instrument 1 and the cap 9 are inserted into the bone cement in an integrated state, the tip of the cap 9 may protrude from the tip of the internal fixation instrument 1 and form a hole in the bone cement and mold it into a predetermined shape.

[0338] The present invention relates to a treatment instrument and a screw, and is particularly suitable for use in surgery in which cement is filled inside the affected bone in advance and a screw is screwed into the cement from the outside of the bone.

[0339] REFERENCE SIGNS LIST 1 Internal fixation tool 2 Outer tube 3 Driver 4 Bone drilling inner tube 5 Cement filling tube 6 Cement pushing rod 7 Cement molding tool 8 Cement fixation tool 9 Cap 10 Treatment tool 11 Head 12, 21 Connection part 13, 33 Fitting part 14, 24, 34, 94, 804 Shaft 15, 42 Tapping thread 16 Inclined part 17 Groove 18 (for fixing the cap or internal fixation tool side) thread 19, 29, 39, 49 Through hole 22 (for pushing out the cement separation tool) outer tube side thread 23 (of the cement separation tool) thread 25 Bone excavation tool 26 Balloon catheter 27 Balloon 28 Cavity 38, 808 Handle 41 Bone drilling part 50 Bone cement 51, 61 Grip 62, 72 Cement molding portion 73 Thread groove 74 Thread 82 Cement fixing portion 90 Skin 91 Pedicle 92 Vertebral body 93 Retraction portion 95 Bone drilling needle 96 Guide pin 97 Guide pipe 98 Cap fixing thread 121 Longitudinal groove 122 Lateral groove 200, 300, 400, 700 Connection mechanism 201 Latch protrusion 202 Wrench fitting portion 211 Protrusion 299 Wrench 301 Latch protrusion 302 Leaf spring 303, 403, 703 Handle 304 Joint portion 305, 405, 705 Connection portion 800 Cement separation tool 801 Tip portion 802 Separation tool side thread

Claims

1. A therapeutic device comprising an internal fixation device to be inserted into a vertebral body through a pedicle and an outer cylinder, wherein the internal fixation device has a head having a first connecting part connectable to the outer cylinder, a shaft extending from the head to a proximal end, a through-hole penetrating the central axis of the shaft, and a tapping screw thread that is tapped onto and screwed into a bone hole formed in the pedicle, and the outer cylinder has a second connecting part connectable to the first connecting part of the internal fixation device, and the connected state between the second connecting part and the first connecting part is maintained against rotation in the direction opposite to the direction in which the internal fixation device is screwed in by the tapping screw thread.

2. A medical device according to claim 1, wherein the first connecting portion and the second connecting portion are connected to each other by a thread in the opposite direction to the tapping thread.

3. A therapeutic device according to claim 1, wherein the second connecting portion has a convex portion, and the first connecting portion has a vertical groove through which the convex portion passes when the outer cylinder is advanced along the central axis toward the internal fixation device to connect with the first connecting portion, and a horizontal groove into which the convex portion fits when the outer cylinder is rotated around the central axis in a direction opposite to the direction in which the tapping screw thread is screwed in when the convex portion reaches the proximal end of the vertical groove, and which restricts further rotation in the opposite direction and linear disconnection along the central axis.

4. A treatment instrument according to claim 1, wherein the treatment instrument further includes a driver, the internal fixation instrument has a first fitting portion at the head, the through hole is a first through hole, the outer cylinder has a second through hole that passes through the central axis and through which the driver can be passed, and the driver has a second fitting portion that fits into the first fitting portion of the internal fixation instrument when inserted into the second through hole.

5. A treatment instrument according to claim 4, wherein the driver is connected to the outer cylinder when fitted into the fitting portion of the internal fixation device, and is provided with a connection mechanism that can be attached and detached by moving the driver along the central axis within the second through-hole.

6. A therapeutic instrument according to claim 5, wherein the connection mechanism comprises a protrusion provided on the outer cylinder in a direction away from the central axis and an elastic body provided on the driver, and is configured so that the elastic body can bend and pass through the protrusion when a force is applied to move the driver along the central axis within the second through-hole.

7. A medical device according to claim 5, wherein the connection mechanism is configured to be able to release the connection between the second connection part and the first connection part while the driver and the outer cylinder are connected.

8. A medical device according to claim 5, wherein the outer cylinder has a wrench fitting portion on its outer periphery.

9. A therapeutic instrument according to claim 4, further comprising a bone-drilling inner cylinder, wherein the driver has a third through-hole along the central axis, the bone-drilling inner cylinder is inserted through the through-hole that communicates when the internal fixation device, the outer cylinder and the driver are connected to one another, and has a bone-drilling portion that protrudes from the tip of the internal fixation device, and the driver is detachably connected to the distal end of the outer cylinder when fitted into the fitting portion of the internal fixation device, and is detachably connected to the bone-drilling inner cylinder at its distal end when the bone-drilling inner cylinder is inserted.

10. A treatment instrument according to claim 9, wherein the bone drilling inner cylinder is connected to the driver by a screw thread in the same direction as the tapping screw thread of the internal fixation instrument.

11. A treatment instrument according to claim 9, wherein the bone drilling inner cylinder has a fourth through-hole that penetrates from the distal end to the tip.

12. A medical instrument according to claim 4, wherein the driver further has a bone-drilling inner cylinder extending proximally from the tip of the fitting portion, and the bone-drilling inner cylinder has a bone-drilling portion that protrudes from its tip through a first through-hole of the internal fixation device when the driver is fitted into the fitting portion of the internal fixation device.

13. A treatment instrument according to claim 12, wherein the tapping screw thread is a first tapping screw thread, and the bone drilling portion has a second tapping screw thread on its outer periphery, and the second tapping screw thread is formed so as to follow the same path as the first tapping screw thread when the driver is fitted into the fitting portion of the internal fixation device.

14. A treatment instrument according to claim 12, wherein the driver has a third through-hole that passes through from the distal end to the tip of the bone-drilling inner cylinder.

15. A treatment instrument according to claim 1, further comprising a cement separation instrument, the treatment instrument being equipped with a motion direction conversion mechanism that is inserted into a through hole that communicates when the internal fixation instrument and the outer tube are connected to each other, and that converts a rotational force that rotates around the central axis of the first through hole into a linear force that moves the cement separation instrument in a straight line along the central axis, with the internal fixation instrument or the outer tube connected to the internal fixation instrument as a fulcrum.

16. A treatment device according to claim 15, wherein the cement separation device has a tip portion that protrudes from the tip of the internal fixation device when inserted into the first and second communicating through holes.

17. A medical device according to claim 15, wherein the outer cylinder has a wrench fitting portion on its outer periphery.

18. A treatment instrument according to claim 4, further comprising a cement filling tube, a cement pushing rod, and a cement fixing device, wherein the driver has a third through-hole, the cement filling tube is inserted into the through-hole that communicates when the internal fixation device, the outer tube, and the driver are connected to one another, the cement pushing rod is inserted along the central axis of the cement filling tube, and has a cement molding part that protrudes from the tip of the internal fixation device, and the cement fixing device is inserted into the through-hole that communicates when the internal fixation device and the outer tube are connected to one another and protrudes from the tip of the internal fixation device, and its tip is inserted into a hole formed in the bone cement in the vertebral body by the cement molding part.

19. A treatment instrument according to claim 4, further comprising a cement molding instrument and a cement fixation instrument, wherein the cement molding instrument is inserted through a through-hole that communicates when the internal fixation instrument, the outer tube, and the driver are connected to one another, and has a cement molding part that protrudes from the tip of the internal fixation instrument, and wherein the cement fixation instrument is inserted through a through-hole that communicates when the internal fixation instrument, the outer tube, and the driver are connected to one another, and protrudes from the tip of the internal fixation instrument, and its tip is inserted into a hole molded in bone cement in the vertebral body by the cement molding instrument.

Images