Screw driver for fastening and fixing by screw, medical member to bone

Abstract

To provide a screw driver which can achieve sure holding of a screw, and facilitate attachment of the screw to a driver head and detachment of the driver head from the screw.SOLUTION: A screw driver 1 for fastening and fixing a medical member to a bone by a screw S comprises: a driver head 2 which is fitted to a drive part S11 provided on a screw head S1 of the screw S; a silicone tube 5 inserted into the driver head 2. When the driver head 2 is fitted to the drive part S11, the silicone tube 5 is elastically stretched and shrunk, thereby covering a periphery of the screw head S1 and gripping the screw S. According to such a configuration, by the silicone tube 5 which is elastically stretched and shrunk, the screw S is gripped, therefore the screw S can be surely held, and attachment of the screw S to the driver head 2 and detachment of the driver head 2 from the screw S can be facilitated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a screwdriver for fastening a medical device to a bone in an orthopedic surgical procedure. [Background technology]

[0002] Conventionally, various orthopedic surgeries have been performed in which medical devices are fastened to bones with screws. One of these orthopedic surgeries is cervical laminoplasty, which is performed to relieve compression of the spinal cord. As shown in Figure 4(a), the spinal cord SC passes through the spinal canal VC, which is surrounded by bones called vertebral arches VA and vertebral bodies VB that form the spine. When this spinal canal VC becomes narrow due to spinal deformation caused by aging or thickening of the ligamentum flavum (not shown), the spinal cord SC is compressed, causing numbness and pain in the lower limbs (spinal canal stenosis).

[0003] Therefore, in cervical laminoplasty, as shown in Fig. 4(b), a recessed hinge part H is formed on one lateral side of the vertebral arch VA (the left side in the figure), and the vertebral arch VA is cut on the other lateral side (the right side in the figure) to form cut parts C, C. Then, as shown in Fig. 4(c), the vertebral arch VA is rotated around the hinge part H, where the thickness of the vertebral arch VA has been reduced, as the axis of rotation so that the cut parts C, C are separated from each other, and the expanded cut parts C, C are fixed with a plate P. This widens the spinal canal VC, relieving the compression of the spinal cord SC.

[0004] The plate P is fastened and fixed to the vertebral arch VA near the cut portions C, C on both the left and right sides with screws (threads) S. The screws S are fastened by a screwdriver having a hexagonal recessed drive section in the screw head and a hexagonal column-shaped driver head that fits into the drive section. Here, screwdrivers used for DIY and the like often have magnetized driver heads, and magnetic screws can be held by magnetic force. However, the screws S used in the medical field are generally made of non-magnetic materials so as not to interfere with MRI examinations that use magnetic force in the future.

[0005] When using a screw S made of such a non-magnetic material, the screwdriver cannot hold the screw S by magnetic force. Therefore, for example, a screwdriver is known in which a pair of arms are provided along a driver head, and the arms grip the screw head to hold the screw S (see, for example, Patent Document 1). It is also conceivable to not provide such arms, but to insert a driver head coated with bone wax (viscous wax) or a driver head with a silicone O-ring attached into the drive unit to detachably hold the screw S. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-173984 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, with the above-mentioned screwdriver, it is not easy to operate because it is time-consuming to attach the screw to the driver head and it is difficult to detach the driver head from the screw head after the screw has been fastened to the vertebral arch.

[0008] The present invention is intended to solve the above-mentioned problems, and aims to provide a screwdriver that can securely hold a screw while easily mounting the screw to the driver head and detaching the driver head from the screw. [Means for solving the problem]

[0009] The present invention is a screwdriver for fastening a medical component to a bone with a screw, comprising a driver head that fits into a drive portion of a screw head of a screw, and a silicone tube that is inserted into the driver head, wherein the silicone tube covers the outer periphery of the screw head and grips the screw when the driver head is fitted into the drive portion.

[0010] The driver head preferably has a threaded portion formed of a male screw that comes into close contact with the inner wall of the silicon tube when the silicon tube is inserted.

[0011] The driver head preferably has a checker portion that serves as a guide for positioning the silicon tube relative to the driver head.

[0012] The silicon tube preferably has a contrast portion with low X-ray transparency. Effect of the Invention

[0013] According to the screwdriver of the present invention, the screw is gripped by the silicon tube, so that the screw can be securely held while the screw can be easily attached to the driver head and the driver head can be easily detached from the screw. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a side view of a screwdriver according to an embodiment of the present invention. [Diagram 2] 4(a)-(c) are side views showing the arrangement of silicon tubes constituting the screwdriver. [Diagram 3] 13(a)-(g) are side views showing the procedure for fastening a plate to a bone with a screw using the screwdriver. [Figure 4] (a)-(c) are diagrams showing the procedure for open-door cervical laminoplasty. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A screwdriver according to one embodiment of the present invention will be described with reference to Figures 1 to 3. This screwdriver is used when fastening a medical component to a bone with a screw in orthopedic surgery, for example, when fastening a plate to a vertebral arch with a screw in cervical laminoplasty.

[0016] As shown in FIG. 1, the screwdriver 1 comprises a driver head 2 connected to a screw S, a shaft portion 3 connected to the driver head 2, a handle portion 4 connected to the shaft portion 3 and used by a user to hold the screwdriver 1, and a silicone tube 5 inserted into the driver head 2.

[0017] The driver head 2 has a main body 21 formed in a round bar shape extending along a predetermined axis Ax, a fitting portion 22 provided at the tip (lower end in the illustrated example) of the main body 21 and fitting with the screw S, a thread portion 23 provided adjacent to the upper end of the fitting portion 22, and a checker portion 24 provided near the base end (upper end in the illustrated example) of the main body 21. The fitting portion 22 is, for example, a hexagonal head, and fits into a hexagonal recessed drive portion S11 provided in the screw head S1 of the screw S. The thread portion 23 is formed by a male screw provided on the outer periphery of the main body 21. The checker portion 24 is formed in a disk shape expanding outward from the main body 21, and serves as a guide for positioning the silicon tube 5 with respect to the driver head 2 as described later. The length of the driver head 2 in the axis Ax direction is, for example, 21 mm, and the thread portion 23 is, for example, M3x0.35.

[0018] The shaft portion 3 is formed in a round bar shape extending along the axis Ax, and has a two-stage structure of a lower shaft portion 31 connected to the upper end of the driver head 2, and an upper shaft portion 32 connected to the upper end of the lower shaft portion 31. The driver head 2, the lower shaft portion 31, and the upper shaft portion 32 are integrally formed of, for example, stainless steel. The upper shaft portion 32 is fixed to the handle portion 4 with most of it inserted through a shaft insertion hole 43 (see below) of the handle portion 4. The lower shaft portion 31 is formed, for example, to have a length of 75 mm and a diameter of 4.5 mm, and the upper shaft portion 32 is formed, for example, to have a length of 60 mm and a diameter of 6.0 mm.

[0019] The handle portion 4 has a grip portion 41 formed in an elongated shape extending along the axis Ax and gripped by a user, and a plurality of recesses 42 provided on the side of the grip portion 41 so that the user's fingers can be easily caught. The handle portion 4 also has a shaft insertion hole 43 recessed along the axis Ax from the center of the lower end face of the grip portion 41 and through which the upper shaft portion 32 is inserted, and a rotation stop pin 44 that stops the upper shaft portion 32 inserted into the shaft insertion hole 43 from freely rotating around the axis Ax with respect to the handle portion 4. The rotation stop pin 44 is inserted into both a pin hole (not shown) provided through the side of the grip portion 41 and a pin hole (not shown) provided in the upper shaft portion 32 corresponding to the pin hole, thereby restricting the handle portion 4 and the upper shaft portion 32 to rotate together around the axis Ax. The handle portion 4 is formed of resin, and may be formed, for example, of onyx resin using a 3D printer. The length of the handle portion 4 in the direction of the axis Ax is, for example, 87 mm.

[0020] As shown in FIG. 2(a), the silicon tube 5 is formed in a cylindrical shape and is made of a semi-transparent or transparent medical heat-resistant stretchable material that has elastic stretchability and can be sterilized by autoclave. The silicon tube 5 has a contrast section 51 with low X-ray transmittance. In the illustrated example, the contrast section 51 is formed in a line shape running parallel to the cylindrical axis and is provided over the entire length of the silicon tube 5. The silicon tube 5 is inserted from the fitting section 22 side of the driver head 2 so as to cover the periphery of the threaded section 23. The inner diameter of the silicon tube 5 is set so that when the silicon tube 5 is inserted into the threaded section 23, the silicon tube 5 adheres closely to the threaded section 23 and does not slip off the threaded section 23 under its own weight.

[0021] 2(b), the length of the silicon tube 5 in the cylindrical axial direction is set so that when the silicon tube 5 is inserted into the threaded portion 23 so that the upper end of the silicon tube 5 matches the checker portion 24 when viewed from the side, the lower end of the silicon tube 5 protrudes downward by, for example, 1 mm from the lower end of the fitting portion 22. Also, as shown in FIG. 2(c), when the silicon tube 5 is inserted into the threaded portion 23 so that the upper end of the silicon tube 5 matches the upper end of the threaded portion 23 when viewed from the side, the lower end of the silicon tube 5 protrudes downward by, for example, 2 mm from the lower end of the fitting portion 22.

[0022] The procedure for fastening a plate to a bone with screws S using the screwdriver 1 configured as above will be described below. First, the procedure for mounting the screws S arranged on a storage tray T to the screwdriver 1 will be described with reference to Figs. 3(a) to 3(d).

[0023] As shown in Fig. 3(a), the screw S is stored on the tray T with the threaded portion S2 inserted into the hole T1 provided in the tray T and the lower end surface of the screw head S1 abutting and locked against the top surface T2 of the tray T. In this state, the screwdriver 1 is brought close from directly above the screw head S1, and the lower end of the silicon tube 5 is placed over the screw head S1 so as to fit the screw head S1 into the inner cavity of the silicon tube 5, as shown in Fig. 3(b).

[0024] In this state, when the screwdriver 1 is further pushed downward while being slowly and lightly moved left and right, as shown in FIG. 3(c), the silicon tube 5 elastically stretches and covers the outer periphery of the screw head S1, and the fitting part 22 of the driver head 2 fits into the driving part S11 of the screw head S1. At this time, it is preferable that the protruding length of the silicon tube 5 from the lower end of the fitting part 22 is set so that when the fitting part 22 is completely fitted into the driving part S11, it covers about 90% of the top of the screw head S1. Then, as shown in FIG. 3(d), when the screwdriver 1 is lifted straight up, the silicon tube 5 becomes a suction cup-like shape that is in close contact with the outer periphery of the screw head S1 and grips the screw S, so that the screw S can be lifted while maintaining the engagement between the driving part S11 and the fitting part 22. In this way, the screw S can be gripped by the screwdriver 1 directly from the tray T.

[0025] Next, with reference to Figs. 3(e) and (g), a procedure for fastening a plate P to a bone B using a screw S held by a screwdriver 1 will be described. First, as shown in Fig. 3(e), a plate P is placed on the bone B, and a screw S is placed directly above a screw hole P1 provided in the plate P. Then, the screw S is brought into contact with the bone B through the screw hole P1, and the screw S is fastened to the bone B by rotating the handle part 4 (not shown) as shown in Fig. 3(f). At this time, care should be taken not to pinch the silicon tube 5 between the screw head S1 and the plate P. Then, as shown in Fig. 3(g), the screwdriver 1 is slowly pulled straight up, and the fitting part 22 and the silicon tube 5 are released from the screw S fastened to the bone B. At this time, the silicon tube 5 returns to its original cylindrical shape due to its elasticity and stretchability.

[0026] As described above, according to the screwdriver 1, the screw S is gripped by the elastically expandable silicone tube 5, so that simply by pushing the silicone tube 5 into the screw head S1, the driver head 2 can be fitted into the screw head S1 and the screw S can be held, and also, simply by pulling the silicone tube 5 away from the screw head S1, the driver head 2 can be disengaged from the screw head S1 and the holding of the screw S can be released. This allows the screw S to be easily attached to the driver head 2 and the driver head 2 to be easily detached from the screw S while ensuring reliable holding of the screw S.

[0027] In addition, since the silicon tube 5 is in intimate contact with the outer periphery of the threaded thread portion 23, the silicon tube 5 can be moved up and down by rotating the silicon tube 5 around the thread portion 23. This makes it possible to easily finely adjust the length of the silicon tube 5 protruding from the lower end of the fitting portion 22 according to the shape and size of the screw head S1.

[0028] In addition, since the checker portion 24 is provided, even if the silicon tube 5 is replaced, as long as the length of the silicon tube 5 is kept constant, the silicon tube 5 protruding a predetermined length from the lower end of the fitting portion 22 can be easily obtained by simply aligning the upper end of the silicon tube 5 with the checker portion 24.

[0029] Furthermore, since the silicon tube 5 is provided with a contrast portion 51 having low X-ray transparency, even if the silicon tube 5 falls or remains inside the body, the contrast portion 51 is clearly visible by X-ray fluoroscopy or the like, and the silicon tube 5 can be easily found.

[0030] The screwdriver according to the present invention is not limited to the above embodiment and may be modified in various ways. For example, the threaded portion and / or the checkered portion do not necessarily have to be provided, and may be configured without these. Also, the silicon tube does not necessarily have to have a contrast portion. Furthermore, the fitting portion is not limited to a hexagonal head, and may be configured with, for example, a torx head, a Phillips head, or a flat head. [Explanation of symbols]

[0031] 1 screwdriver 2 Driver Heads 23 Thread section 24 Checkers Club 5 Silicone tube 51 Contrast department B bone S Screw S1 Screw Head S11 Drive Unit

Claims

1. A screwdriver for fastening a medical device to a bone with a screw, a driver head that fits into a drive portion of a screw head of the screw; a silicon tube that is inserted into the driver head; The screwdriver, wherein the silicone tube covers an outer periphery of the screw head and grips the screw when the driver head is fitted to the drive unit.

2. 2. The screwdriver according to claim 1, wherein the driver head has a threaded portion formed of a male screw that comes into close contact with an inner wall of the silicon tube when the silicon tube is inserted.

3. 3. The screwdriver according to claim 1, wherein the driver head has a checker portion serving as a guide for positioning the silicon tube relative to the driver head.

4. 3. The screwdriver according to claim 1, wherein the silicon tube has a contrast portion with low X-ray transmittance.

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