Pedicle screw cap and fixed washer anti-rotation testing device and testing method

Abstract

The present application relates to a kind of pedicle screw cap and fixed ring anti-rotation test device, including torsion testing machine (1), the torsion testing machine (1) is equipped with rotating three-jaw chuck (2) and fixed three-jaw chuck (3), still including profile bar (4) and fixing mechanism (5), one end of the profile bar (4) is clamped on the rotating three-jaw chuck (2), the other end is closely matched with the fixed ring (10) of the pedicle screw to be measured, the fixing mechanism (5) is clamped on the fixed three-jaw chuck (3), the cap (9) of the pedicle screw to be measured is fixed in the fixing mechanism (5) and the cap (9) is matched with the fixed ring (10), the fixed three-jaw chuck (3) is equipped with torque measuring sensor (6) and the rotating three-jaw chuck (2) is equipped with angular displacement sensor (7). It can realize the anti-rotation mechanics measurement of pedicle screw cap and fixed ring.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology and relates to the reliability testing of pedicle screws for the spine, and in particular to a testing device and method for anti-rotation testing of the pedicle screw cap and fixation ring. Background Technology

[0002] With the rapid development of spinal surgery technology and the maturation of spinal internal fixation techniques, pedicle screws, as a commonly used internal fixation device, are widely used to treat spinal problems arising from trauma, deformity correction, and degenerative spinal diseases. Pedicle screws come in various types, including variable screws, universal screws, and multi-axis screws, providing very strong fixation for the spine. Therefore, comprehensive verification is required regarding the reliability of pedicle screw components and assembly reliability.

[0003] Typically, a pedicle screw consists of a head, a retaining washer, a C-shaped clip, and a screw. During use, when screwing the screw in or out, there is a risk that the retaining washer may detach from the head due to excessive torsion between the retaining washer and the head. Therefore, it is necessary to conduct an anti-rotation test on the pedicle screw head and retaining washer to determine the maximum torsion angle and maximum torque in advance, reducing the risk of the retaining washer detaching from the head due to excessive torsion during actual use.

[0004] However, there is currently no specific device or method for testing the anti-rotation properties of pedicle screw caps and fixation rings, making it impossible to perform anti-rotation tests.

[0005] Given the shortcomings of existing technologies, it is necessary to develop a pedicle screw cap and fixation ring anti-rotation testing device and method. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention proposes a pedicle screw cap and fixation ring anti-rotation testing device and method, which can realize the anti-rotation mechanical measurement of the pedicle screw cap and fixation ring.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A device for testing the anti-rotation properties of a pedicle screw cap and a fixing washer ring includes a torsion testing machine. The torsion testing machine is equipped with a rotating three-jaw chuck and a fixed three-jaw chuck. The device further includes a profiling rod and a fixing mechanism. One end of the profiling rod is clamped on the rotating three-jaw chuck, and the other end is tightly engaged with the fixing washer ring of the pedicle screw to be tested. The fixing mechanism is clamped on the fixed three-jaw chuck. The cap of the pedicle screw to be tested is fixed in the fixing mechanism, and the cap and the fixing washer ring cooperate with each other. The fixed three-jaw chuck is equipped with a torque measuring sensor, and the rotating three-jaw chuck is equipped with an angular displacement sensor.

[0009] Preferably, the nail head has a groove, and the fixing washer has a flap, the groove and the flap cooperate to keep the fixing washer and the nail head fixed.

[0010] Preferably, the other end of the profiling rod is provided with a first side arc surface and a first bottom arc surface, and the fixing washer is provided with a second side arc surface and a second bottom arc surface. The other end of the profiling rod is fixed to the fixing washer through the tight fit between the first side arc surface and the second side arc surface and the tight fit between the first bottom arc surface and the second bottom arc surface.

[0011] Preferably, the fixing mechanism is provided with a contoured groove, the nail head is disposed in the contoured groove, and a slider is provided on each side of the contoured groove, and each slider is provided with a screw capable of manipulating the slider.

[0012] Preferably, the nail head has two arc-shaped protrusions, and each arc-shaped protrusion has a contact surface on both sides. The arc-shaped protrusions cooperate with the arc-shaped inner wall of the contoured groove, and the slider abuts against the contact surface.

[0013] Preferably, the torsion testing machine is further provided with a movable stage, and the fixed three-jaw chuck is mounted on the movable stage.

[0014] Preferably, the length of the portion of the protruding part of the protruding rod between the rotating three-jaw chuck and the fixing mechanism is 10 to 100 mm.

[0015] Furthermore, the present invention also provides a method for performing anti-rotation testing on the pedicle screw cap and fixation ring using the above-mentioned anti-rotation testing device, characterized by comprising the following steps:

[0016] 1) One end of the profiling rod is clamped on the rotating three-jaw chuck, and the other end is tightly fitted with the fixing washer of the pedicle screw to be tested;

[0017] 2) Make the fixing washer ring and the nail head cooperate with each other and fix the nail head in the fixing mechanism;

[0018] 3) The fixing mechanism is clamped by the fixed three-jaw chuck;

[0019] 4) Rotate the three-jaw chuck clockwise at a constant torsional speed of less than or equal to 25° / min, thereby driving the contouring rod to rotate, and driving the fixed washer ring to rotate through the rotation of the contouring rod;

[0020] 5) The fixed washer ring and the nail head rotate relative to each other. The torque is obtained by the torque measuring sensor, the torsion angle is obtained by the angular displacement sensor, and the rotating three-jaw chuck stops rotating when the torque is zero.

[0021] 6) Record the torsion angle and torque during the test, and perform the test multiple times for analysis.

[0022] Preferably, in step 6), the analysis includes obtaining the relationship between torque and torsion angle.

[0023] Preferably, in step 6), the test is performed multiple times for analysis, specifically by calculating the average value of the maximum torque during each test and using it as the anti-rotation torque of the pedicle screw cap and the fixing washer.

[0024] Compared with the prior art, the pedicle screw cap and fixation ring anti-rotation testing device and method of the present invention have one or more of the following beneficial technical effects:

[0025] 1. It can perform anti-rotation mechanical measurement of the pedicle screw head and the fixing washer, thereby obtaining the maximum torsion angle and the maximum torque, reducing the risk of the fixing washer coming off the screw head due to excessive torsion during actual use.

[0026] 2. Its fixing mechanism and nail head are designed to mimic the shape, so that the nail head cannot be twisted in the Z-axis direction after it is fixed, thus ensuring the accuracy of the test.

[0027] 3. Its profiling rod can fit completely with the fixed washer ring, so that the profiling rod does not have relative displacement with the fixed washer ring during the torque transmission process, ensuring that the torque of the testing machine can be completely transmitted to the fixed washer ring.

[0028] 4. The fixing washer and nail head adopt an anti-rotation design. The flaps of the fixing washer and the grooves of the nail head cooperate to allow the two to rotate relative to each other at a certain angle, while keeping the fixing washer from detaching from the nail head under a certain torque.

[0029] 5. By adjusting the gap between the sliders of the fixing mechanism, different specifications of the same pedicle screw can be tested.

[0030] 6. By replacing the profiling rod with a different head shape and the fixing mechanism with different profiling grooves, it is possible to test various types of arch piercing nails, such as variable nails, universal nails, and multi-axis nails. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the pedicle screw cap and fixation ring anti-rotation testing device of the present invention.

[0032] Figure 2 It is a diagram showing the fit between the profiling rod and the fixing washer ring;

[0033] Figure 3 It is a diagram showing the fit between the nail head and the fixing mechanism;

[0034] Figure 4 It is a cross-sectional view of the nail head and the fixing mechanism after they are engaged, to show its internal structure;

[0035] Figure 5 This is a diagram of a nail head;

[0036] Figure 6 This is a schematic diagram of the fixing washer ring;

[0037] Figure 7 This is a schematic diagram of the other end of the profiling rod;

[0038] Figure 8 It is a torque-torsion angle test curve. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments. The content of the embodiments is not intended to limit the scope of protection of the present invention.

[0040] To address the shortcomings of existing technologies, embodiments of the present invention provide a device and method for testing the anti-rotation of the pedicle screw cap and fixation washer, thereby measuring the anti-rotation of the pedicle screw cap and fixation washer, and reducing the risk of the fixation washer dislodging from the screw cap due to excessive torsion during actual use. It should be noted that the accompanying drawings of this specific embodiment are merely examples of the universal joint selected in this invention and should not be construed as limiting the scope of protection of this invention.

[0041] Figure 1 A schematic diagram of the pedicle screw cap and fixation ring anti-rotation testing device of the present invention is shown. Figure 1 As shown, the pedicle screw cap and fixing washer anti-rotation testing device of the present invention includes a torsion testing machine 1. The torsion testing machine 1 is equipped with a rotating three-jaw chuck 2 and a fixed three-jaw chuck 3. During the test, the rotating three-jaw chuck 2 can rotate, thereby driving the fixed part to rotate. The fixed three-jaw chuck 3 remains fixed.

[0042] Preferably, the torsion testing machine 1 is further provided with a movable stage 8. The movable stage 8 is capable of moving left and right on the torsion testing machine 1. The fixed three-jaw chuck 3 is mounted on the movable stage 8. Thus, the distance between the rotating three-jaw chuck 2 and the fixed three-jaw chuck 3 can be adjusted via the movable stage 8.

[0043] The pedicle screw cap and fixing washer anti-rotation testing device of the present invention also includes a contour rod 4 and a fixing mechanism 5. One end of the contour rod 4 is clamped on the rotating three-jaw chuck 2.

[0044] And, as Figure 2 As shown, the other end of the profiling rod 4 is tightly fitted with the fixing ring 10 of the pedicle screw to be tested.

[0045] like Figure 7 As shown, the other end of the profiling rod 4 is provided with a first side arc surface 4.1 and a first bottom arc surface 4.2. Preferably, the other end of the profiling rod 4 is provided with a pair of symmetrically arranged first side arc surfaces 4.1 and a pair of symmetrically arranged first bottom arc surfaces 4.2.

[0046] like Figure 6 As shown, the fixing washer 10 is provided with a second side arc surface 10.3 and a second bottom arc surface 10.2. Preferably, the fixing washer 10 is provided with a pair of symmetrically arranged second side arc surfaces 10.3 and a pair of symmetrically arranged second bottom arc surfaces 10.2.

[0047] In this way, the other end of the profiling rod 4 can be fixed to the fixing washer 10 through the tight fit between the first side arc surface 4.1 and the second side arc surface 10.3 and the tight fit between the first bottom arc surface 4.2 and the second bottom arc surface 10.2.

[0048] Therefore, the profiling rod 4 can fit completely with the fixed pad ring 10, so that the profiling rod 4 does not have relative displacement with the fixed pad ring 10 during the torque transmission process, ensuring that the torque of the testing machine can be completely transmitted to the fixed pad ring 10.

[0049] Continue to refer to Figure 1 The fixing mechanism 5 is clamped onto the fixed three-jaw chuck 3. For example... Figure 3 and Figure 4 As shown, the nail head 9 of the pedicle screw to be tested is fixed in the fixing mechanism 5.

[0050] The fixing mechanism 5 includes a fixing mechanism body 5.1. The fixing mechanism body 5.1 is provided with a contoured groove 5.4. The nail head 9 is disposed in the contoured groove 5.4. A slider 5.2 is provided on each side of the contoured groove 5.4, and each slider 5.2 is provided with a screw 5.3 capable of manipulating the slider 5.2.

[0051] Therefore, by placing the nail head 9 within the contoured groove 5.4 and turning the screw 5.3, the slider 5.2 moves inward, thereby fixing the nail head 9 within the fixing mechanism 5. Furthermore, by adjusting the gap between the sliders 5.2, different specifications of the same type of pedicle screw can be tested.

[0052] Preferably, such as Figure 5As shown, the nail head 9 has two arc-shaped protrusions 9.1. Each arc-shaped protrusion 9.1 has a contact surface 9.2 on both sides. The arc-shaped protrusions 9.1 cooperate with the arc-shaped inner wall of the contoured groove 5.4. The slider 5.2 abuts against the contact surface 9.2.

[0053] Therefore, the fixing mechanism 5 and the nail head 10 are designed to mimic the shape, so that the nail head 9 cannot be twisted in the Z-axis direction after being fixed, thus ensuring the correctness of the test.

[0054] In this invention, such as Figure 2 As shown, the nail cap 9 and the fixing washer ring 10 cooperate with each other.

[0055] like Figure 5 As shown, the nail head 9 has a groove 9.3. Figure 6 As shown, the fixing washer 10 is provided with a flap 10.1. The groove 9.3 cooperates with the flap 10.1 to keep the fixing washer 10 and the nail head 9 fixed.

[0056] Preferably, the length of the groove 9.3 is greater than the length of the flap 10.1, and the groove 9.3 is deeper in the middle and shallower on both sides. This allows for relative rotation at a certain angle, while maintaining the fixing washer 10 from detaching from the nail head 9 under a certain torque.

[0057] In this invention, preferably, the length of the portion of the protruding part of the contour rod 4 between the rotating three-jaw chuck 2 and the fixing mechanism 5 is 10-100 mm. This facilitates torque transmission.

[0058] Furthermore, in this invention, such as Figure 1 As shown, the fixed three-jaw chuck 3 is equipped with a torque measuring sensor 6, and the rotating three-jaw chuck 2 is equipped with an angular displacement sensor 7. The torque measuring sensor 6 can obtain the torque applied during the test. The angular displacement sensor 7 can obtain the torsion angle during the test.

[0059] The following describes how to use the anti-rotation testing device for pedicle screw caps and fixation rings of the present invention to perform anti-rotation testing on pedicle screw caps and fixation rings.

[0060] During testing, one end of the profiling rod 4 is first clamped onto the rotating three-jaw chuck 2, and the other end is tightly fitted with the fixing ring 10 of the pedicle screw to be tested.

[0061] Then, the fixing washer 10 is made to cooperate with the nail head 9 and the nail head 9 is fixed in the fixing mechanism 5.

[0062] Then, the fixed three-jaw chuck 3 is moved by the moving platform 8 so that the fixed three-jaw chuck 3 can clamp the fixing mechanism 5.

[0063] After all the installation and assembly are in place, the rotating three-jaw chuck 2 is rotated clockwise at a constant torsional speed of less than or equal to 25° / min, which drives the contouring rod 4 to rotate, and the rotation of the contouring rod 4 drives the fixed washer ring 10 to rotate.

[0064] During the rotation of the fixed washer ring 10, the fixed washer ring 10 and the nail head 9 undergo relative rotational displacement. The torque is obtained by the torque measuring sensor 6, the torsion angle is obtained by the angular displacement sensor 7, and the rotating three-jaw chuck 2 stops rotating when the torque is zero.

[0065] Record the torsional angle and torque during the test, and perform the test multiple times for analysis.

[0066] In this analysis, the relationship between torque and torsion angle can be obtained, that is, as shown below. Figure 8 The torque-torsion angle test curve is shown. Therefore, in actual use, the torque can be calculated based on the torsion angle.

[0067] Furthermore, the tests were conducted multiple times for analysis. Specifically, the average value of the maximum torque during each test was calculated and used as the anti-rotation torque between the pedicle screw head and the fixing washer. This allows the determination of the maximum torque, preventing the risk of the fixing washer dislodging from the screw head.

[0068] In this invention, by replacing the profiling rod with a different head shape and by changing the fixing mechanism with different profiling grooves, various types of arch piercing nails, such as variable nails, universal nails, and multi-axis nails, can be tested. Therefore, its application range is very wide.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Those skilled in the art can modify or make equivalent substitutions to the technical solutions of the present invention based on the concept of the present invention, without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A pedicle screw cap and fixation washer anti-rotation testing device, comprising a torsion testing machine (1) provided with a rotating chuck (2) and a fixed chuck (3), characterized in that, Further comprising a profiled rod (4) and a fixing mechanism (5), one end of the profiled rod (4) is clamped on the rotating three-jaw chuck (2), the other end is closely matched with a fixing washer (10) of a to-be-tested pedicle screw, the fixing mechanism (5) is clamped on the fixing three-jaw chuck (3), a screw cap (9) of the to-be-tested pedicle screw is fixed in the fixing mechanism (5), the screw cap (9) and the fixing washer (10) are matched with each other, a torque measuring sensor (6) is arranged on the fixing three-jaw chuck (3), and an angular displacement sensor (7) is arranged on the rotating three-jaw chuck (2); During rotation of the fixing washer, the fixing washer and the screw cap are relatively rotated and displaced, torque is obtained through the torque measuring sensor, a torsion angle is obtained through the angular displacement sensor, and the rotating three-jaw chuck is stopped when the torque is zero; The fixing mechanism (5) comprises a fixing mechanism body (5.1), a profiled notch (5.4) is arranged in the fixing mechanism body (5.1), one sliding block (5.2) is arranged on each side of the profiled notch (5.4), and a screw (5.3) capable of driving the sliding block (5.2) is arranged on each sliding block (5.2); the screw cap (9) is arranged in the profiled notch (5.4), the screw (5.3) is screwed to drive the sliding block (5.2) to move, so that the screw cap (9) can be fixed in the fixing mechanism (5), and different specifications of the same type of pedicle screw can be tested by adjusting the gap between the sliding blocks (5.2); Two arc-shaped protrusions (9.1) are arranged on the screw cap (9), one abutting surface (9.2) is arranged on each side of each arc-shaped protrusion (9.1), the arc-shaped protrusions (9.1) are matched with the arc-shaped inner wall of the profiled notch (5.4), and the sliding blocks (5.2) abut against the abutting surfaces (9.2); The screw cap (9) is provided with a groove (9.3), the fixing washer (10) is provided with a wing (10.1), the groove (9.3) and the wing (10.1) are matched to fix the fixing washer (10) and the screw cap (9), the length of the groove is greater than the length of the wing, and the middle of the groove is deep and the two sides of the groove are shallow.

2. The pedicle screw cap and set screw anti-rotation test device of claim 1, wherein, The other end of the profiled rod (4) is provided with a first side arc surface (4.1) and a first bottom arc surface (4.2), the fixing washer (10) is provided with a second side arc surface (10.3) and a second bottom arc surface (10.2), and the other end of the profiled rod (4) is fixed with the fixing washer (10) through close matching of the first side arc surface (4.1) and the second side arc surface (10.3) and close matching of the first bottom arc surface (4.2) and the second bottom arc surface (10.2).

3. The pedicle screw cap and set screw anti-rotation test device of claim 1 or 2, wherein, The torque testing machine (1) is further provided with a moving table (8), and the fixing three-jaw chuck (3) is installed on the moving table (8).

4. The pedicle screw cap and set screw anti-rotation test device of Claim 3, wherein, The exposed part of the profiled rod (4) between the rotating three-jaw chuck (2) and the fixing mechanism (5) has a length of 10-100 mm.

5. A method of testing the anti-rotation of a pedicle screw cap with a fixation washer using the anti-rotation testing device of any one of claims 1-4, wherein, The method comprises the following steps: 1) one end of the profiled rod (4) is clamped on the rotating three-jaw chuck (2) and the other end is tightly matched with the fixing washer (10) of the pedicle screw to be tested; 2) the fixing washer (10) is matched with the screw cap (9) and the screw cap (9) is fixed in the fixing mechanism (5); 3) the fixing mechanism (5) is clamped by the fixing three-jaw chuck (3); 4) the rotating three-jaw chuck (2) is rotated clockwise at a constant torsion speed less than or equal to 25° / min, driving the profiled rod (4) to rotate, and the fixing washer (10) is driven to rotate through the rotation of the profiled rod (4); 5) the fixing washer (10) and the screw cap (9) are relatively rotated and displaced, the torque is obtained through the torque measuring sensor (6), the torsion angle is obtained through the angular displacement sensor (7), and the rotating three-jaw chuck (2) is stopped when the torque is zero; 6) the torsion angle and the torque during the test are recorded, and the test is repeated for analysis.

6. The method of claim 5, wherein, In the step 6), the analysis comprises obtaining the relationship between the torque and the torsion angle.

7. The method of claim 5, wherein, In the step 6), the test is repeated for analysis, specifically: the average value of the maximum torque in each test is obtained and is taken as the anti-rotation torque of the pedicle screw cap and the fixing washer.

Images