Precise forcible entry device for spinal screw arm

Abstract

The invention discloses an accurate forcible entry device for a spinal screw arm, belongs to the technical field of spinal surgical instruments, and solves the problem of safe removal when a screw plug is locked. According to the scheme, a lever system is composed of symmetrically-arranged U-shaped connecting bases, force arm rods with telescopic structures and a grab handle, and a fulcrum is established through a connecting rod with the diameter being 6 mm; the length of the force arm rod can be adjusted from 0 mm to 150 mm through a telescopic locking structure that a cross clamping groove is matched with a cross clamping pin, and about 40-time extrusion force is generated at the position of a screw arm to enable the screw arm to be plastically deformed when separating force F1 is applied to the grab handle by means of the lever ratio of a 400-mm power arm to a 10-mm resistance arm. The device is mainly used for accurately taking out a single locking screw plug in a spinal internal fixation operation, and bone-nail interface looseness and secondary operation injury are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of spinal surgical instruments, and in particular to a screw arm breaking device for removing a locked screw plug in a spinal internal fixation system and an operating method thereof. Background Art

[0002] During spinal fixation surgery, a screw plug, through a hexagonal or torx socket, is used with a wrench to tighten the screw. When the plug hole becomes rounded due to overtightening, or the plug threads become locked with the screw threads, conventional solutions include: crushing the plug with pliers or cutting the connecting rod with shears. These solutions have serious drawbacks.

[0003] 1. Using pliers to clamp will cause the bone-nail interface to loosen, resulting in metal debris that is difficult to clean, causing secondary damage to human tissue;

[0004] 2. After cutting the connecting rod, the entire implant must be removed and reinstalled, which significantly prolongs the operation time. Therefore, it is urgent to develop a special instrument that can accurately destroy a single screw arm without affecting other implants. Summary of the Invention

[0005] The present application provides a demolition device based on the lever principle, which can achieve precise force application to destroy the screw arm while avoiding waste of surgical time and secondary damage.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The spinal screw arm precision demolition device consists of two connecting seats 1, two force arm rods 2, and two handles 3. Its characteristics are: the connecting seat 1 is a U-shaped square block, and the size of the U-shaped mouth is With positive tolerance to match screw arm width With negative tolerance, the front of the square block is set as a plane with rounded arcs on all sides, and the back side has a step surface without chamfers. The back sides of the two connecting seats 1 are interlocked to ensure the cavity size The width of this cavity and the head of the lever 2 is Clearance fit, there are two through holes 1a with a diameter of 4mm and two through holes 1b with a diameter of 6mm on the connecting seat 1, and two connecting rods with a diameter of 4mm are passed through the two 1a holes to fix them together. The connecting rods and the 1a holes are interference fit, and connecting rods with a diameter of 6mm are passed through the 1b holes and 2b holes respectively. The connecting rods and the 1b holes are interference fit, and the 2b holes are clearance fit, and the clearance amount is 0.5mm, so the force arm rod 2 can rotate along the connecting rod with a diameter of 6mm.

[0008] The head of the lever arm 2 is The wide square body has a built-in round hole with a diameter of 10mm and a depth of 150mm, and a cross slot is set in the round hole. The tail of the arm rod 2 is connected to a round rod with a diameter of 10mm. The end of the round rod is provided with a cross pin. The cross pin at the end of the round rod is telescopically nested in the inner hole of the head square body through the cross slot inside the square body. The total length adjustment range of the telescopic connection with the head is 0-150mm.

[0009] The handle 3 is a cylinder with a length of 100 mm and a diameter of 20 mm. The surface is provided with multi-level anti-slip grooves with a depth of 0.5-1 mm. It is made of phenolic resin laminated cloth board, which is light and easy to hold. The inside of the handle 3 is provided with a hole with a length of 50 mm and a diameter of 10 mm. This hole is fixed together with the round rod part of the lever arm 2 by interference fit.

[0010] The lever principle uses the axis of the 6mm connecting rod as the fulcrum. The power F1 is the separation force applied to both sides by the operator holding the handle 3. When the force arm 2 is adjusted to the maximum length, the distance from the separation force point to the fulcrum is the power arm L1, which is about 400mm. The resistance F2 is the inward squeezing force of the head of the force arm 2 clamping the screw arm. The distance from the squeezing screw arm point to the fulcrum is the resistance arm L2, which is about 10mm. It is converted into the squeezing force F2≈40F1 of the head on the screw arm through the lever system.

[0011] Beneficial effects:

[0012] 1. Effort-saving: Through 40 times force amplification, it significantly saves effort and makes the operation easier to control;

[0013] 2. The retractable structure reduces the storage volume of the equipment;

[0014] 3. Simple processing and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view of the overall assembly of the present invention.

[0016] Figure 2 This is a schematic diagram of the present invention in use.

[0017] Figure 3 This is an axonometric view of the connecting seat 1 of the present invention (marked with 1a / 1b hole positions)

[0018] Figure 4 This is the front view of the connector 1 of the present invention (marking the width of the U-shaped opening and the aperture 1b)

[0019] Figure 5 This is a side view of the two connecting bases 1 of the present invention buckled together (showing a 10mm cavity)

[0020] Figure 6 Schematic diagram of the contraction of the lever arm 2 of the present invention (showing the arc angle 2a and the hole 2b and the contraction state)

[0021] Figure 7 The front view of the lever arm 2 of the present invention (showing the aperture 2b and the total length)

[0022] Figure 8 A top view of the lever arm 2 of the present invention (square width of the head)

[0023] Explanation of the accompanying drawings: 1. Connecting seat; 2. Lever arm; 3. Handle; 1a. Two through holes with a diameter of 4 mm; 1b. Two through holes with a diameter of 6 mm; 2a. Arc corner; 2b. Hole with a diameter of 6.5 mm. DETAILED DESCRIPTION

[0024] Combined with attachment Figure 1-8 Further details of this application:

[0025] The present application discloses a spinal screw arm precision breaking device, referring to Figure 1-2 The spinal screw arm precision demolition device is composed of two connecting seats, two force arm rods, and two handles. It uses the principle of lever to artificially apply separation force to generate 40 times the clamping force at the clamping point to achieve the purpose of demolition.

[0026] The following further introduces the assembly process and surgical operation method of this application:

[0027] Assembly process:

[0028] 1. Place the two connecting seats 1 steps facing each other, insert two connecting rods with a diameter of 4mm and fix them through the two 1a holes; after fixing, the side surface will form as follows Figure 5 shown cavity,

[0029] 2 Place the head of the lever arm 2 into The cavity is penetrated by a 6mm diameter connecting rod, which is fixed through the 1b hole with interference fit and the 2b hole with clearance fit (clearance 0.5mm);

[0030] 3. Screw the cross pin of the round rod into the slot of the head and rotate 90° to lock the length;

[0031] 4 The inner hole of the handle 3 is interference fitted with the 50mm section at the end of the round rod.

[0032] Surgical operation method:

[0033] 1. Insert the U-shaped opening onto the target screw arm;

[0034] 2. Hold the handle (3) with both hands and apply a separation force F1 to both sides;

[0035] 3. The head of the arm generates an extrusion force of 40F1, which causes the screw arm to plastically deform;

[0036] 4 Remove the screw plug and deformed screw.

Claims

1. The spinal screw arm precision breaking device is composed of two connecting seats (1), two force arm rods (2) and two handles (3), and is characterized by: The connecting seat (1) is a U-shaped square block, and the size of its U-shaped opening is With screw arm width The front of the square block is set as a plane with rounded arcs on all sides, and the back side is provided with a step surface without chamfers. The back sides of the two connecting seats (1) are interlocked to ensure the cavity size. The width of this cavity and the head of the lever 2 is The connection seat (1) has two through holes 1a with a diameter of 4mm and two through holes 1b with a diameter of 6mm. Two connecting rods with a diameter of 4mm are passed through the two holes 1a to fix them together. The connecting rods and the holes 1a are interference fit. A connecting rod with a diameter of 6mm is passed through the holes 1b and 2b respectively. The connecting rods and the holes 1b are interference fit and the holes 2b are clearance fit. The clearance is 0.5mm. Therefore, the lever arm (2) can rotate along the connecting rod with a diameter of 6mm. The fitting between the connecting rod and the hole 2b serves as a support. point; the handle (3) is interference-connected with the round rod at the end of the lever arm (2); the 6mm connecting rod axis is used as the fulcrum, the power F1 is the separation force applied to both sides by the operator holding the handle 3, when the lever arm 2 is adjusted to the maximum length, the separation force point to the fulcrum is the power arm L1 is about 400mm, the resistance F2 is the inward squeezing force of the lever arm 2 head clamping the screw arm, the squeezing screw arm point to the fulcrum is the resistance arm L2 is about 10mm, and is converted into the squeezing force F2≈40F1 of the head on the screw arm through the lever system.

2. The spinal screw arm precision demolition device according to claim 1, characterized in that: The lever arm (2) is composed of a head block and a tail round rod. The round rod is telescopically nested in a cross slot in the inner hole of the head block through a cross bayonet structure. The cross slot in the block cooperates with the cross bayonet on the round rod in a telescopic locking structure, so that the telescopic length adjustment range is 0-150 mm.

3. The method for using the spinal screw arm precision demolition device according to claim 1 comprises the following steps: The U-shaped opening of the device is clamped to the target screw arm; the handle (3) is held by both hands and a pulling force F1 is applied to both sides; an extrusion force F2 of about 40 times the applied separation force F1 is generated on the head of the force arm rod (2) through the lever action to cause plastic deformation of the screw arm; and the deformed screw and screw plug are removed.

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