Spinal implant having detachable head module and assembly thereof

Abstract

To provide a spinal implant assembly having a detachable head module capable of performing spinal implant surgery simply and conveniently.SOLUTION: A spinal implant comprises: an anchor including a body having a screw thread formed on an outer peripheral surface thereof, and a hollow hole penetrated through the body in an axial direction, and a spherical body having a fixing groove, the anchor being configured to be percutaneously inserted into a vertebral body through skin; a housing 32 including an accommodation portion opened in a transverse direction and having a screw thread formed on an inner peripheral surface thereof, a plurality of grooves formed in a bottom surface of the accommodation portion, and a seating hole penetrated through a lower center of the housing; an inner lock fitted into the seating hole of the housing and having a spherical body hole sized to accommodate the spherical body; a rod 40 configured to connect the anchors in a segmental connection method; and a set screw 60 configured to fix the rod while being fastened to the accommodation portion of the housing. Therein the head module 106 is configured by assembling the set screw in a state in which the inner lock is seated in the seating hole of the housing and the rod is fixed to the grooves.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a spinal pedicle implant and a continuous connection assembly thereof for fixing damaged or deformed vertebrae using a spring rod and wood screws that can be connected at each segment, and more particularly, to a spinal pedicle implant and an assembly thereof having a separate head module that can perform spinal implant surgery conveniently and easily by separating the anchor and head that constitute the wood screw, and assembling the spring rod, which can be connected at each segment, into the head with the direction and angle adjusted. [Background technology]

[0002] Generally, the spine is made up of 24 bones (excluding the fused sacral and coccygeal segments). The spine is connected by joints, and a disk is located between each joint. This structure allows the spine to maintain a human posture while acting as a buffer, and to support the posture in response to the weight and loads applied at various angles, as well as to serve as a foundation for movement and to protect the internal organs. However, if the spine is damaged or deformed due to artificial factors such as external impact, degenerative changes, or abnormal posture that continues for a long time, it will compress the nerves passing through the spinal canal and intervertebral foramen, causing severe pain. When such degenerative diseases progress beyond a certain stage, surgery is required to prevent the damaged or deformed parts of the vertebral segments from pressing or compressing the nerves.

[0003] Representative degenerative spinal diseases include spinal stenosis, spondylolisthesis, and spondylolysis, which are associated with instability between spinal segments. Such degenerative diseases are treated by spinal fusion using a pedicle fixation device.

[0004] Spinal fusion using a pedicle fixation device will now be briefly described with reference to FIGS.

[0005] FIG. 1 is a perspective view showing the configuration of a conventional spinal pedicle fixation device, and FIG. 2 is a schematic diagram showing the conventional spinal pedicle fixation device fixed to a vertebral segment.

[0006] As shown in FIG. 1, the conventional vertebral pedicle fixation device is equipped with a U-shaped groove 301a, a head portion 301 having a female thread formed on the inner surface of the groove 301a, and a screw 302 to be inserted into the vertebral pedicle. The device is composed of a wood screw 300 to be inserted into the damaged vertebral segment, a rod 310 that connects the wood screws 300 to fix the vertebral pedicle, and a set screw 320 with a wrench insertion groove 320a formed on the upper part, which is fastened to the female thread formed in the groove 301a to fix the rod 310.

[0007] As shown in FIG. 2, the above-mentioned conventional vertebral pedicle fixation device involves inserting and fixing the screws 302 of the wood screws 300 into the respective vertebral pedicles 330, placing the rod 310 in the U-shaped storage groove 301a formed in the head portion 301, and then fixing it with a set screw 320.

[0008] The surgical procedure to treat spinal disorders using the conventional spinal pedicle fixation device as described above is one of the most complicated and difficult surgeries. In cases of various surgical deformities, trauma, and spinal fractures, surgeons attempt to "fuse" the spine. In this case, wood screws are attached to the spinal pedicles and rigid or semi-rigid rods are used to connect multiple vertebrae (usually two or more).

[0009] However, due to the complexity of human anatomy, most surgeons place wood screws in two or more misaligned pedicles to properly stabilize the pedicle screw assembly in the patient's body, and then forcibly deform a straight rigid rod to fit the alignment line of the wood screws and connect them. This results in a weakening of the rod's rigidity, and there is a problem that the rod bends or breaks when exposed to loads at various angles during repeated hip movements of extension and flexion after surgery.

[0010] In order to overcome the above problems, the prior art has proposed a multi-joint pedicle screw assembly in US Patent Registration US7,862,594B2 (hereinafter referred to as "Prior Art 1") and a multi-joint pedicle screw system in US Published Patent Application US20040158247A1 (hereinafter referred to as "Prior Art 2"). These patents have a structure in which the wood screw and the head are separated, and the rod can be aligned according to the arrangement line of the wood screw without deforming the rigid rod, which will be described in more detail below.

[0011] As shown in FIG. 3A, Prior Art 1 is composed of a wood screw 202 having a spherical socket groove 204 formed at the upper end, a head part 212 having a sphere 214 with a plurality of cut grooves 214a at the lower part so that the sphere 214 can be fitted into the spherical socket groove 204 and rotate freely, and a storage part 212a for accommodating a rod 216, a saddle pin 218 that penetrates the sphere 214 and is fixed to the spherical socket groove 204 so that the sphere 214 does not come off during the rotation, and a set screw 220 that fixes the rod 216 to the storage part 212a. In this structure, after the wood screw 202 is driven into the vertebral pedicle, the sphere 214 of the head portion 212 is fitted into the spherical socket groove 204 and then fixed with a saddle pin 218. A rod 216 is placed in the storage portion 212a of the head portion 212, allowing the sphere 214 to freely rotate within the spherical socket groove 204.

[0012] As shown in FIG. 3B, Prior Art 2 is composed of a head portion 232 having a thread 232a formed on its outer periphery and a receiving portion 232b having a hole formed vertically through it, a screw portion that passes through the through hole of the head portion 232 and is driven into the vertebral body, a sphere 238 provided on the upper part of the screw portion and having a wrench groove 238a that fits over the through hole, a washer 242 with an aspheric groove formed on the bottom so that the sphere 238 can rotate in close contact with the surface of the sphere, a rod 244 placed on the upper part of the washer 242, a set screw 246 that is fastened to the receiving portion 232b of the head portion 232 and has a wrench groove 246b formed in the center to fix the rod 244 to the head portion 232, and a nut 248 with a thread 248a formed on its inner periphery and fastened to the thread 232a of the head portion 232.

[0013] In the prior arts 1 and 2, the rods 216, 244 are manufactured as a single item in the shape of a rigid straight bar, regardless of the various spinal shapes and positions of the vertebral stems of each patient, which causes many hurdles in the work of connecting them to the vertebral stem wood screws. In other words, if the vertebral joints and the vertebral stem wood screws inserted into the joints are not uniformly aligned, the angle of the head parts 212, 232 is arbitrarily adjusted by the spherical movement of the spheres 214, 238 and the socket groove parts 204, 242 connected to the head parts 212, 232 centered on the wood screws 202, 236 within a predetermined angle range, and then the rods are aligned and fixed. In this way, spinal fusion surgery using a straight rod requires precision surgery, which requires accurate determination of whether the installation positions of the wood screws are uniform, and then holes for inserting the wood screws must be drilled into the vertebral stems, which increases the burden on the surgeon.

[0014] In particular, the articulated screw assemblies with separated heads 212, 232 proposed in Prior Art 1 and Prior Art 2 do not provide sufficient space and flexibility because the rods 216, 244 are located too close to the upper ends of the centers of rotation of the spherical motion of the balls 214, 238 and the socket grooves 204, 242 connected to the heads 212, 232. In addition, it takes a lot of time to forcibly bend a single-shaped straight rod according to the curved shape of the vertebral pedicle and to uniformly connect the rods according to the arrangement line of the wood screws, which causes a problem of prolonged operation time.

[0015] In addition, most of the polyaxial screw assemblies proposed so far have a problem in that they cannot connect the vertebral segments segment by segment, and therefore cannot accommodate various rod lengths that can be applied to multi-segmental segments rather than single segments. Therefore, there is a demand for new and improved pedicle screw assemblies that can overcome the limitations of existing designs, and thus allow surgeons to pursue not only flexibility in surgical procedures but also better outcomes for complete patient rehabilitation. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] US Patent US7,862,594B2 (registered 2011.01.04) [Patent Document 2] US Patent Publication US2004-0158247A1 (Published on August 12, 2004) Summary of the Invention [Problem to be solved by the invention]

[0017] Therefore, the present invention has been proposed to solve the above-mentioned problems, and aims to provide a spinal pedicle implant and its assembly having a separate head module suitable for semirigid fixation, which can continuously connect pedicle wood screws using a spring rod system that can be connected segmentally.

[0018] Another object of the present invention is to provide a spinal pedicle implant and an assembly thereof having a detachable head module in which a head module, which is preassembled externally with a specially constructed inner lock, a rod that can be connected in segments, and a set screw in a housing storage section, is secondarily and stably connected to an anchor ball that is primarily inserted into the body, so that the anchor ball and the head module do not separate from each other even after being connected, and the anchor ball does not move within the head module, thereby maximizing the fixing force.

[0019] Another object of the present invention is to provide a spinal pedicle implant and its assembly having a detachable head module, which allows for simple and convenient spinal implantation by manufacturing a modularized head module with the direction and angle of the spring rods that can be connected segment by segment outside the body before the surgery and connecting it to anchors that are fixed to the vertebral bodies during the surgery, without the need to accurately align the rods to match the anchor alignment line.

[0020] Yet another object of the present invention is to provide a spinal pedicle implant and an assembly thereof having a separate head module that can be continuously connected segment by segment to match the anchor array fixed to the vertebral segment by configuring the head module with a single-connection or double-connection structure of the spring rod attached to the head.

[0021] Another object of the present invention is to provide a spinal pedicle implant and assembly thereof having a detachable head module, which can accurately fix the anchor separated from the head module to the spine with only a small skin incision before the surgery, and which can expose the upper end of the anchor through a midline skin incision and be connected to the head module, thereby shortening surgery time and minimizing bleeding.

[0022] Yet another object of the present invention is to provide a spinal pedicle implant and assembly thereof having a detachable head module that can minimize surgical errors by adjusting the insertion angle and depth of the anchor by inserting a guide wire through the hollow portion of the anchor.

[0023] Another object of the present invention is to provide a spinal pedicle implant and its assembly having a separate head module that can maximize the connection between the screw and the vertebrae by dualizing the pitch of the anchor thread into a dense section and a wide section and connecting them according to the different bone density of each section of the vertebral body. [Means for solving the problem]

[0024] In order to achieve the above object, the present invention provides an anchor including a body having a thread on an outer circumferential surface and a hollow hole penetrating in an axial direction, and a spherical body located at an upper end of the body and having a fixing groove, the anchor being percutaneously inserted into a vertebral body through the skin; a housing having a receiving portion that is open laterally and has a thread on an inner circumferential surface, a plurality of grooves formed on a bottom surface of the receiving portion and a mounting hole penetrating a lower center; an inner rock that is fitted into the mounting hole of the housing and has a spherical hole of a size to receive the sphere; a rod that is placed in the groove of the housing and connects the anchors in a segmental connection form; and a set screw that is fastened to the receiving portion of the housing to fix the rod, The present invention provides a spinal pedicle implant having a separate head module, characterized in that an inner lock is placed in the mounting hole of the housing, and a set screw is assembled with a rod fixed in the groove to form a head module.

[0025] Here, the rod has a straight portion that is placed in the groove of the housing, and a coil portion that is wound at a specific angle based on a center that is eccentrically spaced a certain distance from the center of the straight portion, and is fixed in the groove with its direction and inclination adjusted.

[0026] In the embodiment of the present invention, an inverted U-shaped groove having a size capable of receiving the spherical surface of the rod is formed on one side of the bottom surface, a spherical protrusion having a size capable of being received in the U-shaped groove is formed on the other side of the bottom surface, and a single rod washer may be further included that is placed on the upper part of the groove of the receiving part. This corresponds to the case of a head module to which only one rod is connected.

[0027] As another example of the washer, a double rod washer may be further included, which corresponds to a plurality of grooves of the housing, has an inverted U-shaped groove on the bottom surface of the housing, and is large enough to accommodate the spherical surface of the rod, and is placed on the upper part of the groove of the receiving part. This corresponds to the case of a head module in which two rods are connected.

[0028] The present invention is characterized in that a gap is formed between the inner lock and the lower surface of the mounting hole during the assembly process of the head module, so that the shape of the lower edge of the inner lock does not deform. This ensures that a sufficient coupling space is secured for inserting the sphere into the inner lock during the secondary assembly process in which the sphere of the anchor, which is primarily inserted into the body, is fitted into the head module.

[0029] In an embodiment of the present invention, the inner lock is characterized in that a zigzag cut groove is formed on the outer circumferential surface so that the inner lock has an elastic force that expands and contracts due to the sphere of the anchor inserted inside.

[0030] As another embodiment of the inner lock, the present invention is characterized in that it includes a cylindrical body tapered to be fitted into a mounting hole of a housing, a concave surface formed in a central section of an outer circumferential surface of the cylindrical body and having a thickness thinner than the cylindrical body to provide sufficient elasticity, a cut groove formed at a certain angle in the cylindrical body, a bridge plate formed at a lower end of the cut groove and thinner than the cylindrical body, designed to withstand a preset torque in a head module coupling step and to break when a torque exceeding the preset torque is applied to the set screw in a secondary assembly process with the anchor ball inserted primarily, and a rim formed on a lower end surface of the cylindrical body to shrink inward to increase a fixing force so that the anchor ball does not come off.

[0031] In addition, a female screw groove is formed on the inner peripheral surface of the spherical hole of the inner lock, and a male screw thread is formed on the outer peripheral surface of the sphere of the anchor, thereby maximizing the engagement friction force when the sphere of the anchor is fitted into the spherical hole of the inner lock.

[0032] The anchor has a dual thread structure with a narrow thread pitch in the upper section and a wide thread pitch in the lower section to maximize connection with the vertebral body. That is, the narrow thread pitch portion of the upper section is connected to the cortical bone side of the vertebral body, which has high bone density, and the wide thread pitch portion of the lower section is connected to the cancellous bone side, which has low bone density. Here, the anchor has a self tapper groove that serves as a passageway for smooth removal of bone residue when the anchor is inserted into the bone while rotating.

[0033] In the head module of the present invention, the straight portions on both sides of the rod may be processed to have flat surfaces with flat upper portions in order to set a position reference for being fixed in the groove. In particular, when the rod is fixed with the flat surfaces facing upward, the coil portion is automatically set at an inclination of about 31.7°±5° from the center line of the straight portion, and the coil portions of the rods on both sides are fixed symmetrically on both sides based on the center line of the human body.

[0034] In another embodiment of the rod according to the present invention, the cross-sectional diameter of the straight section of the rod may be larger than the cross-sectional diameter of the coil section.

[0035] In a second embodiment of the present invention, a first to third anchor arrays are provided, each of which comprises a body having a screw thread on its outer circumferential surface and a hollow hole penetrating in the axial direction, and a spherical body having a fixing groove located at the upper end of the body, and which is percutaneously driven into a vertebral body joint through the skin, respectively; a housing having a receiving section which is open laterally and has a screw thread on its inner circumferential surface, a plurality of grooves formed on the bottom surface of the receiving section, and a mounting hole penetrating the lower center; and an inner lock having a spherical hole which is fitted into the mounting hole of the housing and is large enough to receive the spherical body. The present invention provides a spinal pedicle implant assembly having a separable head module including a first and second separable head module arrays that are fitted into the spheres of the anchors of the first to third anchor arrays by grouping head modules each including a rod that connects the anchors in a segmented connection form and a set screw that is fastened to a storage portion of the housing and fixes the rod, the head modules ...

[0036] In the second embodiment of the present invention, the head module is a single rod head module modularized by placing a straight portion of a rod in one of two U-shaped grooves of a housing, fixing the direction and angle of the coil portion of the rod to a certain value, and then fastening the set screw to the storage portion to pressurize and fix the rod, and is characterized in that it has a segmental connection structure in which the head module is connected to the anchors of the first and third anchor arrays, a housing without a rod is fitted to the anchors of the second anchor array, and the rod of the single rod head module is placed in the housing and then fixed with a set screw.

[0037] As a modified example of the second embodiment, the head module is a double rod head module modularized by placing the straight portions of two rods in opposite directions in two U-shaped grooves of a single housing, fixing the direction and angle of the coil portions of the rods to a constant value, and then fastening the set screw to the storage section to pressurize and fix the rods. It may also be a segmental connection structure in which a housing in which no rods are placed on both sides of the double rod head module is fitted into the first and third anchor arrays, and the rods of the double rod head module are placed in one of the two U-shaped grooves of the storage section and then fixed with a set screw.

[0038] In the second embodiment of the present invention, the coil portions of the rods of the first and second head module arrays coupled to the anchors of the first to third anchor arrays are symmetrically positioned on both sides of the spine with respect to the center line of the human body. Effect of the Invention

[0039] According to the present invention as described above, the following effects are obtained.

[0040] First, the inner lock is placed in the mounting hole of the housing outside the body before surgery, and the direction and angle of the spring rod that can be connected to each segment is adjusted and fixed to the housing, and then the head module assembled with the set screw is separated from the anchor that is driven into the vertebral body, making it suitable for semirigid fixation using a single-segment or multi-segment spring rod system. In particular, while the angle and direction of the spring rod were conventionally adjusted inside the patient's body, the head module of the present invention can be inserted after the setting outside the body is completed, so surgery can be performed quickly.

[0041] Second, an inner lock is attached to the receiving part of the housing, the inner lock being composed of a cylindrical body having an elastic thin concave surface, a thin bridge plate formed at the lower end of an incision groove formed at a certain angle on the cylindrical body, and a rim formed on the lower end surface of the cylindrical body so as to shrink inward. With this structure, the head module pre-assembled outside and the anchor inserted into the body are stably coupled, and the anchor sphere and the head module are not separated from each other even after being coupled, and the fixing force is maximized so that the anchor sphere does not move within the head module.

[0042] Third, the angle and direction of the spring rods, which can be connected to each segment via the head module, can be adjusted and set outside the body in advance, allowing for natural segmental alignment, eliminating the need for separate rod fixing position setting and rod alignment during surgery, making spinal implant surgery simple and easy, and significantly shortening the surgery time.

[0043] Fourth, before the main operation, a small skin incision is made and only the anchor can be accurately fixed to the vertebral body. In addition, during the main operation, the mid-line skin is incised, and the top of the fixed anchor is exposed after a small amount of muscle detachment on the side of the spine, and then the head module is attached. This surgical process not only shortens the operation time, but also reduces muscle damage with minimal skin ligation and minimizes bleeding.

[0044] Fifth, the thread pitch of the upper section of the anchor is narrowed to connect with the cortical bone of the vertebral body, which has high bone density, and the thread pitch of the lower section is widened to connect with the cancellous bone of the vertebral body, which has low bone density, thereby maximizing the connection with the vertebral body through the dual thread structure of the anchor.

[0045] Sixth, by forming a hollow portion penetrating the anchor in the axial direction and passing a guide wire through the hollow portion, the insertion angle and depth of the anchor can be adjusted using the guide wire inserted into the vertebral body before the actual surgery, thereby minimizing errors in the insertion direction and insertion depth of the anchor.

[0046] Seventh, by forming a hexagonal lobe wrench groove on the sphere of the anchor, the ease of connection with a surgical instrument can be maximized, and the connecting rotation force for driving into the vertebral body can be made stronger.

[0047] Eighth, a self tapper groove is separately processed on the dual thread of the anchor, so that when the anchor is inserted while cutting the vertebrae, the cut bone can be smoothly removed. [Brief description of the drawings]

[0048] [Figure 1] FIG. 1 is a perspective view showing the configuration of a spinal pedicle fixation device according to the prior art. [Diagram 2] FIG. 1 is a schematic diagram of a prior art pedicle fixation device attached to a vertebral segment. [Figure 3A] FIG. 1 is an exemplary diagram showing the configuration of a prior art articulated spinal pedicle assembly. [Figure 3B] FIG. 1 is an exemplary diagram showing the configuration of a prior art articulated spinal pedicle assembly. [Figure 4] FIG. 1 is an exploded perspective view showing an embodiment of a spinal pedicle implant assembly having a separate head module according to the present invention. [Diagram 5] FIG. 2 is an exploded perspective view showing the configuration of a separate head module, which is a main part of the spinal pedicle implant assembly according to the present invention. [Figure 6] FIG. 2 is an exploded perspective view showing a coupled state of an anchor and a housing, which are essential parts of the present invention. [Figure 7] FIG. 2 is a perspective view showing a configuration of an inner lock which is a main part of the present invention. [Figure 8] FIG. 8 is a cross-sectional view of FIG. [Figure 9] FIG. 4 is a perspective view showing a state in which the housing and the inner lock are joined together. [Figure 10] FIG. 7 is a combined cross-sectional view of FIG. 6. [Figure 11] FIG. 2 is a perspective assembled view of a spinal pedicle implant assembly having a split head module according to the present invention, the perspective assembled view showing a single rod head module. [Figure 12] FIG. 2 is a perspective assembled view of a spinal pedicle implant assembly having a split head module according to the present invention, the perspective assembled view showing a dual rod head module. [Figure 13] FIG. 11 is a perspective view showing another embodiment of a spring rod in the present invention. [Figure 14] FIG. 14 is a cross-sectional view of FIG. [Figure 15] 11 is a cross-sectional view showing the configuration of a single rod washer added to a separated type head module in the present invention. FIG. [Figure 16] 11 is a cross-sectional view showing a configuration of a double rod washer added to a separated type head module in the present invention. FIG. [Figure 17]13 is a diagram showing a state in which a guide wire is inserted before the anchor according to the present invention is driven into a vertebral body. [Figure 18] FIG. 13 is a diagram showing a state in which an anchor has been driven into a vertebral body along a guide wire in the correct direction. [Figure 19] FIG. 13 is a diagram showing a state in which an anchor is driven into a vertebral body in the wrong direction without a guide wire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings of FIGS.

[0050] The spinal pedicle implant having a separate head module and its assembly according to the present invention are realized to shorten the operation time and simplify the operation by accurately fixing the anchor to the vertebral body before the main operation and connecting the head module with a rod connected thereto during the main operation.

[0051] The present invention relates to an assembly suitable for a spring rod system that can be connected in segments, which has been developed by the applicant of the present application, and the detailed configuration thereof will be described with reference to FIGS.

[0052] Figure 4 is an exploded oblique view showing the configuration of one embodiment of a spinal pedicle implant assembly having a separate head module according to the present invention, Figure 5 is an exploded oblique view showing the configuration of a separate head module, which is an essential part of the spinal pedicle implant assembly according to the present invention, Figure 6 is an exploded oblique view showing the connected state of the anchor and housing, which are essential parts of the present invention, Figure 7 is an oblique view showing the configuration of the inner lock, which is an essential part of the present invention, Figure 8 is a cross-sectional view of Figure 7, Figure 9 is an oblique view showing the connected state of the housing and inner lock, and Figure 10 is a cross-sectional view of the connection of Figure 6.

[0053] As shown in the figure, the spinal pedicle implant of this embodiment is large and consists of an anchor 10 that is driven percutaneously through the skin into the pedicle and vertebral body, and a separate head module 30 that connects the anchor 10 to fix the spine.

[0054] Explaining the detailed configuration, as shown in Figures 4 and 10, the anchor 10 is composed of a body 12 having a thread on its outer peripheral surface and a hollow hole 12a penetrating in the axial direction, a spherical body 14 located at the upper end of the body 12 and having a wrench groove 14a, and a neck portion 16 connecting the body 12 and the spherical body 14.

[0055] Here, the body 12 of the anchor has a dual thread structure in which the thread pitch (a) of the upper section is narrow and the thread pitch (b) of the lower section is wide to maximize the connection with the bone. In general, the part where the anchor 10 is inserted into the spine is the pedicle and the vertebral body, and the vertebral body is further divided into the cortical bone and the cancellous bone. Among them, the pedicle and the cortical part of the vertebral body have high bone density, so the thread pitch (a) of the upper section with a narrow pitch is connected, and the bone density of the cancellous part of the vertebral body is low, so the thread pitch (b) of the lower section with a wide pitch is connected, thereby maximizing the connection between the anchor 10 and the vertebral body 204.

[0056] In this embodiment, a self tapper groove 13 is separately machined on the thread (b) of the body 12, and serves as a passageway for smoothly discharging bone debris when the anchor 10 is rotated and inserted into the bone.

[0057] In addition, a male screw thread 14b is machined on the outer circumferential surface of the ball 14, maximizing the coupling friction with a female screw groove formed on the inner surface of an inner lock, which will be described later.

[0058] The wrench groove 14a of the ball 14 is formed in a hexagonal lobe to maximize the coupling and torque of the surgical instrument. This is because the instrument and the anchor can be coupled only when the hexagonal wrench groove 14a is precisely aligned with the tip end of the surgical instrument, increasing the coupling between the instrument and the anchor. Also, the coupling torque of the hexagonal groove is greater than that of the cross groove.

[0059] In the configuration of the anchor 10 described above, the hollow hole 12a of the body 12 serves as a passage for the guide wire 202. That is, by drilling holes in the pedicle and vertebral body 204 along a predetermined path in advance, inserting the guide wire 202 into the drilled hole, and then passing the guide wire 202 through the hollow hole 12a of the body 12, it is possible to check the angle and depth of insertion into the pedicle and vertebral body 204 based on the guide wire 202, thereby minimizing the possibility of errors in the insertion direction and insertion depth of the anchor.

[0060] More specifically, as shown in Figures 17 and 18, after the guide wire is inserted into the vertebral body 204 at a predetermined insertion angle and depth (as shown in Figure 17), the guide wire 202 is passed through the hollow hole 12a of the anchor 10, so that the insertion angle of the anchor 10 is set to the same. Thereafter, if the anchor 10 is inserted into the vertebral body 204 to the same depth as the wire is inserted, the anchor 10 is accurately driven into the vertebral body at the specified angle and depth (as shown in Figure 18). Figure 19 is a diagram showing that the anchor 10 is driven into the vertebral body 204 at an incorrect direction and angle without the guide wire 202.

[0061] The head module 30 is open laterally as shown in FIGS. 5 and 6, and includes a receiving section 34 having a screw thread 34a formed on its inner circumferential surface, a housing 32 having a plurality of “U” shaped grooves 36 formed on the bottom surface of the receiving section 34 and a mounting hole 35 penetrating the lower center, an inner rock 38 fitted into the mounting hole 35 of the housing 32 and having a sphere hole 38a large enough to receive the sphere 14, a rod 40 placed in the U shaped groove 36 of the housing 32 to connect the anchor driven into the vertebrae and maintain the vertebral fixation state, and a set screw 60 fastened to the receiving section 34 of the housing 32 to fix the rod 40.

[0062] Here, the inner lock 38 has a vertical zigzag cut groove 38b formed on the outer circumferential surface so that the sphere hole 38a has an elastic force that expands and contracts. According to the above structure, when the sphere 14 is fitted into the sphere hole 38a, the sphere hole 38a expands due to the cut groove 38b, so that the sphere 14 is smoothly fitted therein, and after the sphere 14 is accommodated in the sphere hole 38a, it contracts. In this state, the neck portion 16 of the anchor 10 is caught on a step (not shown) formed on the bottom of the mounting hole 35 of the housing 32 and does not come out.

[0063] The operating principle of the inner lock 38 having the above structure will now be described.

[0064] In order to make the head module 30 externally, after the rod 40 is placed in the groove 36 of the housing 32, torque is applied to the set screw 60 to fix the rod so that it does not come off or move. The inner lock 38 inside the mounting hole 35 of the housing 32 is pushed in the torque direction of the set screw 60 and contracts along the inner surface of the mounting hole 35 of the housing 32, partially contracting the inner diameter. In this state, when the sphere 14 is fitted into the inner lock 38 of the head module 30, the inner diameter temporarily increases, and then when the set screw 60 is fully tightened, the inner lock 38 further contracts to surround and fix the sphere 14.

[0065] The inner lock 38, which operates as described above, is coupled to the mounting hole 35 of the housing 32 in order to form the head module 30 before being coupled to the sphere 14 of the anchor 10. In this state, when the rod 40 is mounted in the receiving portion 34 of the housing 32 and tightened with the set screw 60, there is a possibility that the space (hole) corresponding to the internal diameter through which the sphere 14 of the inner lock 80 should pass and be coupled is reduced, resulting in a problem of not being able to couple with the sphere 14. To prevent this problem, another embodiment of the inner lock 80 in the present invention is shown in Figures 7 and 8.

[0066] As shown in the figure, the inner lock 80 forms a tapered cylindrical body 82 to be fitted into the mounting hole 35 of the housing 32, and the central section of the cylindrical body 82 is formed of a concave surface 84 having elasticity, which provides sufficient elasticity to expand and contract in association with the engagement of the sphere 14. That is, the thickness of the concave surface 84 is formed thinner than the thickness of the cylindrical body 82. Therefore, at the moment the sphere 14 of the anchor 10 is fitted into the cylindrical body 82, the cylindrical body 82 expands due to the elastic action of the concave surface 84, and then contracts again to its original position to restore to surround the sphere 14.

[0067] A vertically cut groove 86 is formed on the outer periphery of the cylindrical body 82, and a bridge plate 88 thinner than the cylindrical body 82 is integrally provided on the bottom of the cut groove 86. In the process of assembling the head module 30 in which the inner lock 80 is coupled to the mounting hole 35 of the housing 32, when the rod 40 is mounted in the receiving portion 34 of the housing 32 and then the set screw 60 is tightened, the bridge plate 88 is designed to maintain the shape of the inner lock 80 while enduring a preset constant torque (maximum 1 to 1.3 N in this embodiment), and in the process of secondary assembly of the ball 14 of the anchor 10 and the head module 30, which is inserted primarily, the bridge plate 88 has a characteristic of breaking only when a torque greater than the set torque is applied through the set screw. That is, the bridge plate 86 is designed so that the mounting hole 35 of the housing 32 is temporarily expanded and coupled to the ball 14 while breaking during the process of strongly tightening the set screw 60 after the head module 30 is fitted to the ball 14 of the anchor 10. The cylindrical body 82 has an internal thread groove 90 formed on the upper and lower parts of its inner circumferential surface, which is coupled with the external thread 14b of the ball 14 to provide a strong coupling friction force.

[0068] In addition, a rim 92 is formed at the lower end of the cylindrical body 82, which is inwardly contracted and surrounds the neck portion of the bottom surface of the sphere 14 to complement the coupling force.

[0069] Hereinafter, the operation process when the inner lock 80 constructed as above is fitted onto the sphere 14 will be described in more detail.

[0070] In the present embodiment, the inner lock 80 is fixed by slightly expanding the inner diameter of the cylindrical body 82 as the ball 14 of the anchor 10 passes through and is inserted into the space corresponding to the inner diameter of the cylindrical body 82, and then contracting again. That is, when the head module 30 is manufactured, the cylindrical body 82 is not completely fitted into the mounting hole 35 of the housing 32 and is positioned to protrude slightly upward, and this position corresponds to the point where the rod 40 first comes into contact when the set screw 60 is tightened. With this configuration, a space in which the ball 14 can be coupled can be secured inside the housing 32. That is, when the rod 40 is lightly fastened by the set screw 60 during the assembly process of the head module 30, the cylindrical body 82 of the inner lock 80 is not completely fitted into the mounting hole 35 and is slightly floating, minimizing the deformation of the inner lock 80. At this time, the point at which the inner lock 80 is deformed is adjusted according to the magnitude of the torque applied to the set screw 60. That is, the bridge plate 88 is not broken (damaged) up to a certain torque (maximum 1 to 1.3 N) and plays a role in preventing deformation while maintaining the overall cylindrical shape of the inner lock 80. In addition, when the set screw 60 is lightly tightened to 1.3 N or less during the assembly stage of the head module 30, the shape of the head module 30 is maintained without the rod 40 coming off the housing 32. In particular, since the shape of the inner lock 80 is maintained without deformation on the mounting hole 35 of the housing 32, a space is secured for smooth secondary coupling and alignment between the sphere 14 of the anchor 10 that has already been inserted into the body and the head module 30. Even if the inner hole space of the inner lock 80 is partially narrow during the process of secondary coupling of the head module 30 to the anchor 10 that has been primarily inserted into the body, the sphere 14 can relatively more easily enter the inner space of the inner lock 80 due to the elasticity of the concave surface 84. Due to the reinforced elasticity of the concave surface 84, the torque applied to the inner lock 80 and the housing 32 during the coupling process can be dispersed while preventing the phenomenon of concentration at a specific point to some extent.

[0071] After the sphere 14 is coupled to the inside of the inner lock 80 of the head module 30, the set screw 60 is strongly tightened using an anti-torque driver and a final driver (not shown) with a torque greater than this (about 12N or more). During this process, the bridge plate 88 breaks and the cylindrical body 82 of the inner lock 80 deforms, surrounding the surface of the sphere 14 and providing tension to provide a strong coupling. At this time, if the set screw 60 is coupled with a strong torque (currently exceeding about 2N) during the process of assembling the head module 30 to the anchor 10, the bridge plate 88 breaks and the inner lock 80 completely contracts, making it impossible to recouple the head module 30 to the anchor 10 inserted in the body later.

[0072] The rod 40 is composed of a straight portion 42 placed in the groove 36 of the housing 32, and a coil portion 44 wound at a specific angle with respect to a center that is a certain distance eccentric to the center of the straight portion 42. In this embodiment, the coil portion 44 of the rod 40 is wound two times.

[0073] Another embodiment of the rod 40 is shown in FIGS.

[0074] In an embodiment of the present invention, the straight portions 42 on both sides of the rod 40 may have flat surfaces 42a on their upper surfaces in order to set a reference for the installation position of the rod 40, as shown in Fig. 13. When the rod 40 is installed with the flat surfaces 42a facing upward, the coil portions 44 are automatically erected at an inclination of about 31.7°±5° from the center line of the straight portions 42, and the coil portions 44 of the rods 40 on both sides are installed symmetrically on both sides based on the center line of the human body.

[0075] 14, the cross-sectional diameter of the straight section 42 of the rod 40 is formed to be larger than the cross-sectional diameter of the coil section 44. This is to delay the time when fatigue fracture of the straight section 42 occurs or to maintain it semi-permanently when observed clinically long after the lumbar fixation surgery, so that the rod 40 can maintain its rigidity to the maximum extent within the allowable range of the fixing operation.

[0076] The rod 40 of the above structure prevents the spine from tilting to one side, and limits the curvature of the lower back when the spine is bent backward compared to the movement when the spine is bent forward. It also has a biomechanical structure similar to the normal load distribution structure between multiple fused spinal segments, thereby realizing the effect of reducing the burden on the lower back.

[0077] In the separated head module 30 having the above configuration, when the rod 40 is placed in one of the two U-shaped grooves 36 of the housing 32, the other groove 36' remains as an empty space, and the load may not be distributed uniformly when the set screw 60 is pressurized and fixed. To prevent this, in the present invention, a single rod washer 46 and a double rod washer 48 can be additionally configured as shown in Figures 15 and 16.

[0078] FIG. 15 is a diagram showing the configuration of a single rod washer, and FIG. 16 shows the configuration of a double rod washer.

[0079] The single rod washer 46 shown in FIG. 15 has an inverted U-shaped groove 46a formed on one side of the bottom surface, which is large enough to accommodate the spherical surface of the rod 40, and a spherical protrusion 47 formed on the other side of the bottom surface, which is large enough to be accommodated in the U-shaped groove 36'.

[0080] The double rod washer 48 shown in FIG. 16 has a structure in which double inverted U-shaped grooves 48a are formed so as to accommodate the spherical surfaces of two rods 40 placed in the U-shaped grooves 36, 36' when the rods are connected in series.

[0081] The spinal pedicle implant assembly having the above-mentioned structure of the separate head module fixes the spine with a segmental connection structure. That is, in the present invention, the anchors 10 are driven into the vertebral segments to form the first to third anchor arrays 102, 103, and 104. A single rod head module 106 and a double rod head module 106 are attached to the first to third anchor arrays 102, 103, and 104. FIG. 11 shows an example in which the single rod head module 106 is connected to the first to third anchor arrays 102, 103, and 104 to which three anchors 10 are bound, and FIG. 12 shows an example in which the double rod head module 108 is connected to the first to third anchor arrays 102, 103, and 104 to which three anchors 10 are bound.

[0082] The single rod head module 106 shown in FIG. 11 is modularized by placing a rod 40 in one of the two U-grooves 36 of the housing 32, fixing the direction and angle of the coil part 44 of the rod 40, and then fastening the set screw 60 to the receiving part 32 to pressurize and fix the rod 40. The single rod head module 106 assembled as described above is naturally aligned according to the shape of the spine by fitting the ball 14 of the anchor 10 into the ball hole 38a of the inner lock 38, and the spine is fixed. The housing 32' on which the rod 40 is not placed is fitted into the second anchor array 103 in the center. In this state, the rods of the single rod head module 106 are placed in the two U-grooves 36 of the housing 32, respectively, to be connected, forming a segmented connection method.

[0083] The double rod head module 106 shown in Fig. 12 is modularized by placing two rods 40, 40' in the two U-grooves 36 of the single housing 32 in opposite directions, fixing the direction and angle of the coil part 44 of the rod 40 to a certain value, and then fastening the set screw 60 to the receiving part 32 to pressurize and fix the rod 40. The double rod head module 108 assembled as described above is naturally aligned according to the shape of the spine by fitting the ball 14 of the anchor 10 into the ball hole 38a of the inner lock 38, and the spine is fixed. Then, the housing 32' on both sides of the double rod head module 108 on which no rod is placed is fitted into the first and third anchor arrays 102, 104, and the rod 40 of the double rod head module 108 is placed in one of the two U-grooves 36 of the receiving part to connect them.

[0084] According to the present invention configured as described above, before the actual surgery, a small skin incision is made, a guide wire is inserted into the vertebral body, and the guide wire is fitted into the hollow hole 12a of the anchor body 12, and then the anchor 10 is inserted into the vertebral body 204. During this process, it is possible to check whether the angle or direction is deviated, and the insertion depth of the anchor 10 can be checked and adjusted.

[0085] When the anchor 10 is driven into the node of the vertebral body 204 before the actual surgery, the single rod head module 106 or double rod head module 108, in which the coil portion 44 of the rod 40 is placed in a certain direction and at a set inclination angle in the U-shaped groove of the housing, is assembled to the anchor 10 exposed outside the vertebral body to complete the fixation procedure of the pedicle screw.

[0086] According to this procedure, the head module 30 prepared outside the body is simply fitted to the anchor 10, so the pedicle screw can be fixed accurately and simply. This significantly shortens the operation time, and since only the anchor 10 is inserted into the vertebral body, only a minimal skin incision is required, so the amount of bleeding is reduced. In particular, the pedicle screw can be accurately set by confirming and guiding only the surgical position (the position where the anchor is driven) from a photo of the pedicle derived by C-ARM.

[0087] In the process of fixing the pedicle implant assembly using the above-mentioned separate head module, the coil portions 44 of the rods 40 on both sides are naturally fixed in a symmetrical manner without being tilted to one side based on the center line of the human body.

[0088] Without the need to forcibly bend the rod, the direction and angle of the coil portion 44 of the eccentric rod 40 are aligned in a constant and symmetrical manner based on the centerline of the human body, so that natural sagittal balance and lordosis can be maintained.

[0089] Generally, in the case of flexion, the pressure is higher at the front side of the disk, and in the case of extension, the pressure is higher at the rear side of the disk. In the neutral state, the pressures at the front and rear of the disk are at similar levels. If the head module 30 of the present invention is connected to the anchor 10 with the direction and inclination of the rod 40 properly aligned, the coil part 44 is wound around the center of the straight part 42 of the rod 40, which is offset by a certain distance (d), and therefore, although the pressure value is slightly lower than that of a normal disk pressure profile, a uniform unloading effect with a similar overall graph pattern is obtained.

[0090] In addition, the spine does not move at a single specific segment, but rather the movements of each segment are combined to perform flexion and extension as a whole. The movement of each segment is usually referred to as ROM (Range of Motion), and this is the result of general spinal biomechanical analysis, which shows that the ROM of the operated segment is relatively small, while the ROM of the adjacent segments above and below the operated segment is large. Therefore, the accelerated adjacent segment degeneration of the segments above and below the operated segment is also due to this unnatural spinal mechanical movement.

[0091] According to the structure of the head module 30 in which the straight portion 42 and the coil portion 44 are fixed to the housing 32 with a central eccentricity and a specific inclination, the rod 40 operates in a manner in which the movement is greater during flexion, which is the motion of bending the waist forward, and is smaller during extension, which is the motion of straightening the waist backward, thereby deriving results similar to the actual biomechanical movement of the spine.

[0092] In addition, compared to surgery using a rigid rod, the ROM of the operated segment is maximized and the ROM of the adjacent segments is minimized. Furthermore, the finite element analysis of the case where the spinal pedicle fixation device of the present invention is attached to the posterior part of the spine between the segments of the vertebral body 204 and a spinal fusion cage is used in combination with the anterior part of the spine confirmed that the load distribution ratio between the anterior and posterior parts is 7:3 or 7.5:2.5, which is close to the normal load sharing mechanism ratio of 8:2. As a result, adjacent segment degeneration of the upper and lower adjacent segments of the operated segment can be minimized.

[0093] In spinal loading experiments using the structure of the present invention, the ratio of the anterior and posterior parts reaches a similar level to normal load distribution in the case of semirigid fixation. This not only reduces the possibility of reoperation due to articulatory segment degeneration (ASD), but also reduces stiff (flat) back syndrome. It also shortens the rehabilitation period after surgery.

[0094] Although specific embodiments of the present invention have been described above, the idea and scope of the present invention are not limited to these specific embodiments, and it will be understood by those skilled in the art to which the present invention pertains that various modifications and variations are possible without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0095] 10: Anchor 12: Body 14: Spherical 16: Neck portion 30: Separate head module 32: Housing 34: Storage area 35: Placement hole 36: U-groove 38, 80: Inner lock 40: Rod 42: Straight section 44: Coil section 46: Single rod washer 48: Double rod washer 60: Set screw 82: Cylindrical body 84: Concave 86: Incision groove 88: Bridge plate 90: Female thread groove 92: Rim 202: Guidewire 204: Vertebrae a: Thread of the upper section b: Thread of the lower section

Claims

1. An anchor including a body having a screw thread on an outer circumferential surface and a hollow hole penetrating in an axial direction, and a spherical body having a fixing groove located at an upper end of the body, the anchor being percutaneously inserted into a vertebral body through the skin; a housing having a storage section that is open laterally and has a screw thread formed on an inner peripheral surface, a plurality of grooves formed on a bottom surface of the storage section, and a mounting hole that penetrates the center of a lower portion; an inner lock that is fitted into the mounting hole of the housing and has a sphere hole of a size that accommodates the sphere; a rod mounted in a groove of the housing and connecting the anchors in a segmented connection configuration; a set screw that is fastened to the housing and fixes the rod, A spinal pedicle implant having a separate head module, characterized in that an inner lock is placed in the mounting hole of the housing, and a set screw is assembled with a rod fixed in the groove to form a head module.

2. The spinal pedicle implant with a separated head module as described in claim 1, characterized in that the rod has a straight portion that is placed in the groove of the housing and a coil portion that is wound at a specific angle based on a center that is eccentrically spaced a certain distance from the center of the straight portion, and is fixed in the groove with its direction and inclination adjusted.

3. The spinal pedicle implant with a separated head module as described in claim 1, characterized in that an inverted U-shaped groove of a size capable of receiving the spherical surface of the rod is formed on one side of the bottom surface, a spherical protrusion of a size to be received in the U-shaped groove is formed on the other side of the bottom surface, and a single rod washer is further included that is placed on the top of the groove of the receiving part.

4. The spinal pedicle implant having a separated head module as described in claim 1, further comprising a double rod washer that corresponds to the groove of the housing, has an inverted U-shaped groove on its bottom surface that is large enough to accommodate the spherical surface of the rod, and is placed on top of the groove of the receiving portion.

5. The spinal pedicle implant having a separate head module as described in claim 2, characterized in that a gap is formed between the inner lock and the lower surface of the mounting hole to prevent the shape of the lower part of the inner lock from being deformed during the assembly process of the head module.

6. The spinal pedicle implant having a separate head module as described in claim 5, characterized in that the inner lock has an incised groove formed in a zigzag pattern in the vertical direction on its outer circumferential surface so that the spherical hole has an elastic force that expands and contracts.

7. The inner lock has a tapered cylindrical body that is fitted into a mounting hole of a housing; a concave surface formed in a central section of an outer circumferential surface of the cylindrical body and having a thickness smaller than that of the cylindrical body in order to provide a sufficient elastic force; a cut groove formed at a certain angle on the cylindrical body; a bridge plate formed at a lower end of the cut groove and thinner than the cylindrical body, designed to withstand a preset torque in a head module coupling step and to break when a torque exceeding the preset torque is applied to the set screw in a secondary assembly step with the ball of the anchor that has been primarily inserted; The spinal pedicle implant having a split head module according to claim 5, further comprising a rim formed on a lower end surface of the cylindrical body so as to shrink inward.

8. The spinal pedicle implant having a separated head module according to claim 7, wherein a female thread groove is formed on the inner peripheral surface of the spherical hole of the inner lock, and a male thread is formed on the outer peripheral surface of the sphere, so that when the sphere is fitted into the spherical hole, the coupling friction force can be maximized.

9. The spinal pedicle implant with a separated head module according to claim 1, wherein the anchor has a dual thread structure in which the thread pitch in the upper section is narrow and the thread pitch in the lower section is wide, in order to maximize connectivity with the vertebral body.

10. The spinal pedicle implant having a detachable head module according to claim 9, characterized in that a self-tapper groove is machined on the thread of the anchor to serve as a passage for smoothly discharging bone debris when the anchor is rotated and inserted into the bone.

11. The spinal pedicle implant with a split head module according to claim 1 , wherein the fixing groove formed on the sphere of the anchor is a hexagonal wrench groove.

12. The spinal pedicle implant having a separated head module as described in claim 2, characterized in that the straight portions on both sides of the rod are formed with flat surfaces at the top to set positional references to be fixed into the grooves.

13. The spinal pedicle implant with a separate head module as described in claim 12, characterized in that when the rod is fixed with the flat surface facing upward, the coil portion is automatically erected at an inclination of approximately 31.7°±5° from the center line of the straight portion, and the coil portions of the rods on both sides are fixed symmetrically on both sides based on the center line of the human body.

14. The spinal pedicle implant having a separate head module according to claim 1 , wherein the cross-sectional diameter of the straight section of the rod is larger than the cross-sectional diameter of the coil section.

15. a body having a screw thread on an outer circumferential surface and a hollow hole penetrating in an axial direction, and a spherical body having a fixing groove located at an upper end of the body, the first to third anchor arrays being made up of a group of anchors each of which is driven percutaneously through the skin into a vertebral body joint; a housing having a receiving section that is open laterally and has a screw thread formed on an inner circumferential surface, a plurality of grooves formed on a bottom surface of the receiving section, and a mounting hole penetrating a lower center; an inner rock that is fitted into the mounting hole of the housing and has a spherical hole of a size to receive the sphere; a straight section that is mounted in the groove of the housing, and a coil section that is wound at an inclination of a specific angle with respect to a center that is eccentrically spaced a certain distance from the center of the straight section, the head modules including a rod that connects the anchors in a segmental connection form, and a set screw that is fastened to the receiving section of the housing to fix the rod, the spinal pedicle implant assembly having a separated head module, comprising: a first and second separated head module arrays that are fitted into the spheres of each anchor of the first to third anchor arrays, the first and second separated head module arrays being grouped together to be fitted into the spheres of each anchor of the first to third anchor arrays.

16. The head module is a single rod head module modularized by placing a rod in one of two U-shaped grooves of the housing, fixing the direction and angle of the coil part of the rod to a certain value, and then tightening the set screw to the receiving part to pressurize and fix the rod, and is a segmental connection structure in which the head module is connected to the anchors of the first and third anchor arrays, a housing without a rod is fitted to the anchors of the second anchor array, and the rod of the single rod head module is placed in the housing and then fixed with a set screw.

17. The head module is a double rod head module modularized by placing straight portions of two rods in opposite directions in two U-grooves of a single housing, fixing the direction and angle of the coil portion of the rod to a certain value, and then fastening the set screw to the receiving part to pressurize and fix the rod, and the head module is a segmental connection structure in which housings on both sides of the double rod head module in which no rods are placed are fitted into the first and third anchor arrays, and the rods of the double rod head module are placed in one of the two U-grooves of the receiving part and then fixed with a set screw.

18. The spinal pedicle implant assembly having a separated head module as described in claim 15, characterized in that the coil portions of the rods of the first and second head module arrays coupled to each anchor of the first to third anchor arrays are located symmetrically on both sides of the spine based on the center line of the human body.

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