A special tool for taking out the top wire of a difficult-to-take-out pedicle screw in orthopedics

Abstract

The utility model provides a special take-out tool of difficult-to-take-out pedicle screw top wire in orthopedics, belongs to the technical field of spinal surgery instrument, and the tool includes movable handle, head sleeve, pressurizing sleeve, anchor rod support and replaceable screw driver head, tap head and cutter head, the anchor rod support is used as counterforce support base, holds vertebral body connecting rod through both sides of eagle beak shape anchor rod hook, and is locked and fixed through anchor screw, the pressurizing sleeve is matched with anchor rod support screw pair, realizes screw step pressurizing, extrudes the bearing step of head sleeve downwards, and output continues axial pressure, the lower end of head sleeve can insert different function head, and the three kinds of clinical working conditions of nail groove perfect fastening top wire, sliding groove top wire and thread cross-knocking jammed top wire are processed in stages, the utility model relies on axial pressurizing to offset the outward slippage component force of head, adopts manual slow operation completely, replaces electric drill high speed polishing, avoids metal micro-fragment splashing and remaining, bone destruction is small, and the success rate of operation is high, head is modularized and can be replaced individually, and main part can be repeatedly used, and the clinical problem that the difficult-to-take-out pedicle screw top wire is taken out in the operation of spinal internal fixation taking-out is solved.

Description

Technical Field

[0001] This invention relates to the field of spinal surgery instruments, and in particular to a specialized tool for removing pedicle screws that are difficult to remove in orthopedics. Background Technology

[0002] Lumbar pedicle screw-rod fusion surgery is widely used to treat lumbar disc degeneration, lumbar instability, lumbar spondylolisthesis, spinal stenosis, and other diseases. Pedicle screws are inserted into the pedicles of the vertebral bodies, and a connecting rod is inserted through the screw head. A setter screw is then screwed into the internal thread of the screw head to tighten the connecting rod, achieving multi-segment vertebral fixation. To ensure reliable screw-rod locking, a large tightening torque is applied to the setter screw during surgery. Later, during removal of the internal fixation, issues such as excessively tight setter screw threads, misaligned threads, and cold weld jamming frequently occur. If the setter screw cannot be loosened and removed, the entire screw-rod system cannot be disassembled. Currently, only a matching screwdriver can be used clinically to remove set screws in good condition. When set screws are stuck or slippage occurs, there is a lack of specialized instruments, and only destructive emergency measures can be used: cutting the connecting rod, but this is difficult due to limited surgical space and often requires bone removal; using an electric drill to grind and destroy the set screw, but high-speed grinding produces a large amount of metal micro-shavings that are difficult to clean out of the soft tissue; if these measures fail, the internal fixation must be permanently left in the body, causing pain and rejection risks to the patient, and increasing the financial burden of a second surgery. Existing treatment methods are highly destructive and risky, and there is a lack of specialized instruments for removing stuck, slipped, or mis-threaded set screws. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a specialized tool for removing difficult-to-remove pedicle screws in orthopedics. This solves the current problem of the lack of specialized removal instruments for difficult-to-remove pedicle screws in orthopedics, improving the efficiency of removing difficult-to-remove screws, shortening operation time, reducing bone destruction and intraoperative bleeding, avoiding surgical infection due to residual fragments, and even preventing removal failure.

[0004] To address the aforementioned technical problems, this invention provides a device for removing difficult-to-remove pedicle screws in orthopedics, comprising a movable handle, a bit sleeve, a pressure sleeve, an anchor rod support, and multiple sets of replaceable bits. The movable handle is a T-shaped detachable handle, with a straight-line drive grip fixed to the upper part and a hollow hexagonal prism-shaped sleeve insertion groove at the lower part. The upper part of the bit sleeve is a bit sleeve insertion connector, which can engage with the sleeve insertion groove to achieve torque transmission. The bit sleeve consists of a small-diameter body, a load-bearing step, and a large-diameter body from top to bottom. The bottom end of the bit sleeve has a bit insertion groove for inserting replaceable bits. The pressure sleeve is a hollow cylinder, with a small-diameter constraint channel and a large-diameter constraint channel inside. The bit sleeve is assembled inside the pressure sleeve, forming a bushing sliding structure. The lower part of the outer wall of the pressure sleeve has external threads. The anchor rod bracket is a reaction support base; the main body of the anchor rod bracket is a hollow cylinder, with an internally threaded cylinder at the top, and the external thread and the internally threaded cylinder are screwed together to form a threaded pair; the lower ends of both sides of the anchor rod bracket are beak-shaped anchor rod hooks, which are used to hold the vertebral connecting rod; the anchor rod bracket is equipped with locking rod screws, which are used to lock and fix the anchor rod bracket to the vertebral connecting rod; when rotating the pressure sleeve, the pressure sleeve spirals downward, presses against the bearing step, and outputs continuous axial compressive force to the bit sleeve.

[0005] Furthermore, the replaceable bits include screwdriver bits, tap bits, and wedge bits; screwdriver bits are available in various sizes for removing set screws with intact cap grooves; tap bits are used to enlarge and tap the slots of set screw caps, creating a new torque engagement contact surface; the annular wedge end at the bottom of the wedge bit cuts through the misaligned thread to lock the outer edge of the set screw, achieving separation of the locked set screw from the pedicle screw head.

[0006] The working principle of this device is as follows: The anchor rod support relies on the double-sided eagle-beak shaped anchor rod hooks to hold the cone-shaped connecting rod, and tightening the locking rod screws completes the fixation, constructing a reaction force countermeasure platform. The pressure sleeve relies on the helical step output of the threaded pair to continuously output axial pressure, offsetting the component force of the bit slipping and lifting; the bit sleeve is constrained by the cavity of the pressure sleeve, limiting radial displacement and ensuring coaxiality; the pressure sleeve squeezes the load-bearing step of the bit sleeve, completely transferring the axial pressure to the front bit. Different bits can be used to handle three scenarios: fastening set screws with intact cap grooves, slipping set screws, and set screws stuck due to thread misalignment; the bits are consumable parts and can be replaced individually, while the other main components can be reused.

[0007] Compared with existing technologies, the beneficial effects of this invention are: 1. The anchor rod bracket, combined with the pressure support structure, solves the problems of axial force lifting and bit slippage in traditional pedicle screw removal tools, significantly improving the success rate of removing difficult-to-remove pedicle screws. 2. Three-level layered adaptation: one set of tools covers all clinical difficulties such as intact and tight pedicle screws, slipped pedicle screws, and mis-threaded and stuck pedicle screws. 3. Modular and replaceable bits, adaptable to different specifications of pedicle screws from various manufacturers; worn bits can be replaced separately, and the main components can be reused, reducing usage costs. 4. The cutting bit slowly circumferentially cuts the outer edge of the pedicle screw under axial pressure, replacing high-speed grinding with an electric drill; the cutting product is large-particle chips, which are easy to clean during surgery, avoiding the splashing and residue of metal micro-shavings, and reducing the risk of postoperative infection. 5. The T-shaped movable handle and pressure sleeve are equipped with long lever arm grips, making operation easier, shortening the operation time, and reducing intraoperative bleeding. 6. The overall structure is simple and can be manufactured using ordinary medical tool steel, which is convenient for hospitals to configure in batches and reduce the medical expenses of patients undergoing secondary surgery; the operation process is standardized, the learning threshold for spinal surgeons is low, and destructive emergency operations such as cutting connecting rods and grinding set screws during surgery are reduced. Attached Figure Description

[0008] Figure 1 is a schematic diagram of the assembly of the device of the present invention; Figure 2 Figure 3 is a schematic diagram of the components of the device of the present invention; Figure 4 is a cross-sectional view of the present invention in the working state of removing the cap groove and tightening the set screw; Figure 5 is a cross-sectional view of the present invention in the working state of removing the slide groove set screw; Figure 6 is a cross-sectional view of the present invention in the working state of the cutting tool bit circumferentially cutting the misaligned set screw.

[0009] Explanation of reference numerals in the attached drawings: 1-Moving handle, 1.1-Moving handle drive grip, 1.2-Sleeve insertion slot; 2-Bit sleeve, 2.1-Bit sleeve insertion connector, 2.2-Small diameter shaft, 2.3-Bearing step, 2.4-Large diameter shaft, 2.5-Bit insertion slot; 3-Pressure sleeve, 3.1-Small diameter constraint channel, 3.2-Pressure sleeve drive grip, 3.3-Pressure sleeve external thread, 3.4-Large diameter constraint channel; 4-Anchor rod bracket, 4.1-Inner part of the anchor rod bracket Threaded cylinder; 4.2-locking bar thread; 4.3-anchor bar hook; 5-locking bar screw; 6-screwdriver bit; 6.1-screwdriver bit connector; 6.2-screwdriver head; 7-taper bit; 7.1-taper bit connector; 7.2-taper head; 8-wedge bit; 8.1-wedge bit connector; 8.2-ring wedge port; 9-undamaged fastening set screw; 10-set screw for nail groove; 11-set screw for misaligned threads; 12-cone connecting rod; 13-pedicle screw. Detailed Implementation

[0010] Basic instrument assembly: Attach the anchor hook of the anchor rod bracket to the connecting rods on both sides of the pedicle screw, adjust the angle of the anchor rod bracket so that the internal thread of the anchor rod bracket is coaxial with the target set screw; tighten the locking rod screws on both sides to lock and fix the anchor rod bracket to the connecting rod.

[0011] Example 1: Remove the intact fastening screw from the cap groove ( Figure 3 This embodiment is applicable to set screws that cannot be loosened by conventional screwdrivers, but whose cap groove structure remains intact. Select a screwdriver bit of the matching specification and insert it into the bit insertion slot of the bit sleeve; insert the bit sleeve into the pressure sleeve; screw the pressure sleeve into the internal threaded cylinder of the anchor rod bracket; then insert the movable handle into the bit sleeve insertion connector. With one hand, rotate the pressure sleeve to drive the handle screw downwards, pressing the pressure sleeve bearing step; after fully pressing, rotate the pressure sleeve half a turn in the opposite direction to allow a slight retraction stroke for the bit sleeve; with the other hand, hold the movable handle and rotate it counterclockwise with full force to try to loosen the set screw; while gradually retracting the pressure sleeve, continue rotating the movable handle until the set screw is completely unscrewed. If the bit slips in the groove during the operation, switch to the groove set screw removal mode.

[0012] Example 2: Removal of the sliding groove set screw ( Figure 4 Keep the anchor rod bracket fixed on the connecting rod; remove the pressure sleeve, pull out the bit sleeve, replace with a tap bit of the corresponding specification, and reassemble the entire tool set. Apply continuous axial pressure downwards by rotating the pressure sleeve with one hand, while simultaneously rotating the movable handle counterclockwise; the tap bit, under axial pressure, cuts into the already rounded set screw groove, establishing a new engagement drive surface. After the tap bit has penetrated to a sufficient depth, retract the pressure sleeve half a turn; rotate the movable handle counterclockwise with full force to try to unscrew the set screw; if it still cannot be loosened, you can gradually replace with tap bits of larger outer diameter and repeat the cutting and tapping operation. If the set screw is still stuck, it is a case of thread misalignment, then switch to a thread misalignment set screw treatment solution.

[0013] Example 3: Removal of misaligned thread set screws ( Figure 5 The procedure involves changing the cutting tool bit and inserting it into the bit sleeve; then inserting the bit sleeve into the pressure sleeve; finally, screwing the pressure sleeve into the threaded sleeve inside the anchor rod bracket. With one hand, rotate the pressure sleeve downwards to continuously apply pressure, while with the other hand, rotate the movable handle counterclockwise at a uniform speed. Under the combined action of axial pressure and rotational torque, the annular cutting tool bit progressively cuts around the outer edge of the set wire until the jammed set wire is separated from the pedicle screw head, releasing the screw rod from its locking position. The cutting produces large metal chips, which can be directly cleaned during the procedure without leaving any flying debris. After completing the circumferential cutting, the entire device can be removed, and the spinal screw rod system can be subsequently extracted.

[0014] This invention is not limited to the above-described embodiments. Any simple modifications or equivalent substitutions made by those skilled in the art based on the technical solutions of this invention shall fall within the protection scope of this invention.

Claims

1. A device for removing pedicle screws that are difficult to remove in orthopedics, characterized in that, The device includes a movable handle (1), a bit sleeve (2), a pressure sleeve (3), an anchor rod bracket (4), and multiple sets of replaceable bits. The movable handle (1) is a T-shaped detachable handle. The upper part of the movable handle (1) is fixed with a straight movable handle drive grip (1.1), and the lower part is a hollow hexagonal prism-shaped sleeve insertion groove (1.2). The upper part of the bit sleeve (2) is a bit sleeve insertion connector (2.1), which can be inserted into the sleeve insertion groove (1.2) to achieve torque transmission. The bit sleeve (2) consists of a small diameter body (2.2), a load-bearing step (2.3), and a large diameter body (2.4) from top to bottom. The bottom end of the bit sleeve (2) is a bit insertion groove (2.5), which is used to insert replaceable bits. The pressure sleeve (3) is a hollow cylinder, and the inside of the pressure sleeve (3) is a small-diameter constraint channel (3.1) and a large-diameter constraint channel (3.4); the bit sleeve (2) is assembled inside the pressure sleeve (3), and the small-diameter rod (2.2) and the large-diameter rod (2.4) are fitted inside the small-diameter constraint channel (3.1) and the large-diameter constraint channel (3.4), which together form a bushing sliding structure; the lower part of the outer wall of the pressure sleeve (3) is the external thread of the pressure sleeve (3.3); the anchor rod bracket (4) is a reaction support base; the main body of the anchor rod bracket (4) is a hollow cylinder, the upper part of the cylinder is the internal thread cylinder of the anchor rod bracket (4.1), the lower ends of both sides of the anchor rod bracket (4) are eagle beak-shaped anchor rod hooks (4.3), and the locking rod screw (5) is used to lock and fix the anchor rod bracket (4) on the cone connecting rod (12).

2. The special removal tool for difficult-to-remove screws in orthopedics according to claim 1, characterized in that, The upper part of the bit sleeve (2) is a small-diameter rod (2.2), and the lower part is a large-diameter rod (2.4), forming a load-bearing step (2.3) through the change of diameter.

3. A special tool for removing difficult-to-remove screws in orthopedics according to claim 1, characterized in that, The upper part of the outer wall of the pressure sleeve (3) is fixed with a symmetrical one-line pressure sleeve drive handle (3.2), the lower part of the outer wall of the sleeve is provided with a pressure sleeve external thread (3.3), the upper part of the inner wall of the sleeve is a small diameter constraint channel (3.1), the lower part of the inner wall of the sleeve is a large diameter constraint channel (3.4), the bit sleeve (2) is fitted and constrained in the pressure sleeve (3), and the bearing step (2.3) receives the axial pressure of the pressure sleeve (3) and transmits the pressure downward to various bits.

4. A special tool for removing difficult-to-remove screws in orthopedics according to claim 1, characterized in that, The anchor rod bracket (4) is a reaction support base. The main body of the anchor rod bracket (4) is a hollow cylinder. The upper part of the cylinder is an internal threaded cylinder (4.1) of the anchor rod bracket. The external thread (3.3) of the pressure sleeve and the internal threaded cylinder (4.1) of the anchor rod bracket are screwed together to form a threaded pair. The lower end of the anchor rod bracket (4) has two eagle beak-shaped anchor rod hooks (4.3) on both sides. The anchor rod hooks (4.3) are used to hold the vertebral connecting rod (12). The anchor rod bracket (4) is equipped with locking rod screws (5). The locking rod screws (5) are used to lock the anchor rod bracket (4) onto the vertebral connecting rod (12).

5. The orthopedic pedicle screw extraction device for difficult-to-remove screws according to claim 1, characterized in that, The replaceable bit includes an annular cutting bit (8); the annular cutting bit (8) has a hexagonal prism-shaped connector (8.1) at the top and a hollow cylinder at the bottom, with a serrated annular cutting end (8.2) at the bottom; the cutting bit (8) is used to cut the outer edge of the threaded set screw (11) and separate the stuck set screw from the head of the pedicle screw (13).

6. The orthopedic pedicle screw extraction device for difficult-to-remove pedicle screws according to claim 5, characterized in that, The active handle (1), bit sleeve (2), pressure sleeve (3), and anchor rod bracket (4) are reusable components; the screwdriver bit (6), tap bit (7), and cutting bit (8) are modular bit assemblies that can be replaced individually after wear.

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