CN216985110U - Spinal fixation system - Google Patents

Abstract

The utility model relates to a vertebral fixing system which comprises a fixing plate, wherein the fixing plate is provided with a plurality of rows of screw holes penetrating through the fixing plate, mounting holes penetrating through the fixing plate are formed between adjacent screw holes in the same row, anti-back nails are arranged in the mounting holes, one ends of the anti-back nails are connected with fastening covers for fixing the anti-back nails on the fixing plate, the mounting holes are provided with elastic pieces, the elastic pieces are positioned between the fixing plate and the fastening covers, and the fastening covers tightly press the elastic pieces on the fixing plate. The elastic piece is subjected to certain axial pressure, so that damping feeling is generated between the anti-withdrawal nail and the fixing plate. When the nail is prevented from being withdrawn in a rotating mode, the operation hand feeling is better. In addition, the elastic part that utilizes the compression produces foretell damping and feels, need not utilize the deformation of preventing moving back nail itself to realize the damping function, consequently can not appear preventing moving back nail deformation too big and lead to inside micro crack to appear, avoid taking place the fracture in the use, avoid preventing moving back the functional failure then.

Description

Spinal fixation system

Technical Field

The utility model relates to the technical field of medical instruments, in particular to a vertebral fixing system.

Background

The anterior cervical plate system generally comprises an anterior cervical plate, bone screws and anti-backing nails. It is commonly used in the operation of cervical vertebra fracture dislocation or cervical intervertebral disc excision fusion in clinic. Because the cervical vertebra of a human body needs to move frequently in daily life, the bone screw is easy to loosen and withdraw after the anterior cervical steel plate is implanted. In addition, when the anatomical position of the cervical vertebra is seen, human tissues such as the esophagus and the trachea are arranged on the front side of the cervical vertebra, if the bone screw is loosened and withdrawn, the tissues can be stimulated to cause discomfort of a patient, and if the bone screw is serious, the esophagus can be abraded to cause serious injury to the patient. Therefore, after the bone screw is implanted, the loosening and withdrawing of the bone screw are strictly forbidden clinically. The cervical vertebra anterior steel plates on the market at present are limited by anti-retreat nails to withdraw bone screws, and the anti-retreat nails are connected with the cervical vertebra anterior steel plates through riveting technology.

The stability of riveting type is uncontrollable, because doctor's custom producer product prevents moving back the nail and has certain damping sense before implanting the bone screw clinically, does not influence follow-up bone screw of going up in their operation like this, and the riveting type is by preventing the deformation of moving back nail itself and realizing its function, so when deformation is too big, the circumstances such as locking difficulty can appear, prevent moving back nail inside microcrack that appears even, the circumstances such as fracture appear after implanting, the patient needs to carry out urgent surgical treatment. When the deformation is too small, the screw withdrawal prevention device has no damping feeling before the bone screw is implanted, has extremely poor experience feeling for doctors, and even has no blocking feeling after the bone screw is implanted, so that the screw withdrawal prevention effect cannot be achieved.

SUMMERY OF THE UTILITY MODEL

Accordingly, the present invention is directed to a vertebral fixation system that can provide a certain damping effect before the bone screw is implanted, thereby improving the experience of the doctor, and that does not break due to the presence of micro-cracks inside the bone screw after the bone screw is implanted.

The utility model provides a vertebra fixing system, includes the fixed plate, the fixed plate is equipped with a plurality of rows and runs through the screw of fixed plate is equipped with between the adjacent screw in same row and runs through the mounting hole of fixed plate, be equipped with in the mounting hole and prevent moving back the nail, the one end of preventing moving back the nail be connected with will prevent moving back the nail and be fixed in the fastening lid of fixed plate, be equipped with the elastic component in the mounting hole, the elastic component is located the fixed plate with between the fastening lid, the fastening lid will the elastic component compress tightly in the fixed plate.

According to the spine fixing system, the elastic piece is subjected to certain axial pressure, so that damping feeling is generated between the anti-withdrawal nail and the fixing plate. When the anti-back nail is rotated, a doctor can feel the damping, and the operation hand feeling is better. In addition, the elastic part that utilizes the compression produces foretell damping and feels, need not utilize the deformation of preventing moving back nail itself to realize the damping function, consequently can not appear preventing moving back nail deformation too big and lead to inside micro crack to appear, avoid taking place the fracture in the use, avoid preventing moving back the functional failure then.

In one embodiment, the screw hole is provided with a bone screw; the anti-withdrawal nail comprises a head part and a rod part connected with the head part, wherein grooves are respectively arranged on two opposite sides of the head part in the first direction and are used for avoiding the bone screw; the opposite ends of the head in the second direction can rotate to the position for axially limiting the bone screw, the second direction is perpendicular to the first direction, and the fastening cover is connected to one end, far away from the head, of the rod.

In one embodiment, the distance between two grooves of the head part of the same anti-back nail is smaller than the distance between adjacent screw holes in the same column so as to avoid the bone screw; the distance between two opposite sides of the head part in the second direction is greater than that of the adjacent screw holes in the same column, so that the two end parts can axially limit the bone screw.

In one embodiment, when the head of the anti-back nail axially limits the bone screw, the head presses the bone screw against the fixing plate from one side of the bone screw, which is opposite to the fixing plate; alternatively, the head is tangential to the bone screw.

In one embodiment, the rod portion is a smooth cylinder, the fastening cover is wrapped and sleeved on the tubular structure on the rod portion, and the fastening cover is connected with the smooth cylinder.

In one embodiment, a side of the head portion facing away from the fixing plate is provided with a driving interface, and the driving interface is used for being matched with a tool to drive the anti-withdrawal nail to rotate.

In one embodiment, the mounting hole comprises a first large-diameter hole, a small-diameter hole and a second large-diameter hole which are connected in sequence along the axial direction of the mounting hole, the elastic piece is accommodated in the second large-diameter hole, and the length of the rod part in the axial direction is smaller than the sum of the three dimensions of the length of the small-diameter hole, the height of the elastic piece and the height of the fastening cover; the terminal surface of fastening lid with prevent moving back the terminal surface parallel and level of nail or be less than prevent moving back the terminal surface of nail.

In one embodiment, the elastic element comprises an annular sleeving part and a cylindrical abutting part connected with the sleeving part, the sleeving part is sleeved on the anti-back nail, the abutting part extends towards the fixed plate, and the aperture of the abutting part at the end part close to the fixed plate is larger than that of the end part far away from the fixed plate.

In one embodiment, the elastic member is a disk spring or a spring.

In one embodiment, the fixing plate is provided with a through observation window.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the utility model, and are incorporated in and constitute a part of this specification.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic view of a spinal fixation system according to an embodiment.

Fig. 2 is a cross-sectional schematic view of the spinal fixation system of fig. 1.

Fig. 3 is a schematic structural view of the fixing plate.

Fig. 4 is a schematic cross-sectional view of the fixing plate of fig. 3.

Fig. 5 is a schematic structural view of the anti-backing nail.

FIG. 6 is a side view of the anti-backup nail of FIG. 5.

Fig. 7 is a schematic structural view of a disc-shaped spring.

Fig. 8 is a top view of the disk shaped spring of fig. 7.

Fig. 9 is a structural view of the fastening cover.

Fig. 10 is a top view of the securing cap of fig. 9.

The relevant elements in the figures are numbered correspondingly as follows:

100. a spinal fixation system; 10. a fixing plate; 101. a front side; 102. a back side; 110. a screw hole; 120. Mounting holes; 121. a first large-diameter hole; 122. a small-diameter hole; 123. a second large-diameter hole; 130. an observation window; 20. preventing the nail from moving back; 210. a head portion; 211. a groove; 212. an end portion; 220. a rod portion; 230. a drive interface; 30. an elastic member; 310. a housing portion; 320. an abutting portion; 40. a fastening cover; 50. a bone screw.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the utility model and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the utility model.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be interconnected within two elements or in a relationship where two elements interact with each other unless otherwise specifically limited. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Embodiments of the present invention provide a spinal fixation system for reconstructing spinal stability. For example, the spinal fixation system may be an anterior cervical fixation system or a thoracolumbar fixation system. In this embodiment, a spine fixation system is taken as an anterior cervical fixation system, and is applied to cervical vertebra fracture dislocation or cervical intervertebral discectomy fusion surgery as an example for explanation.

As shown in fig. 1 and 2, a vertebral fixing system 100 according to an embodiment of the present invention includes a fixing plate 10, anti-withdrawal nails 20 pre-installed on the fixing plate 10, elastic members 30, and a fastening cap 40. The spinal fixation system 100 also includes bone screws 50 mounted posteriorly on the fixation plate 10. Wherein bone screw 50 is intended for implantation in the human body. The elastic member 30 and the fastening cover 40 serve to give a damping feeling when the anti-retreat pin 20 rotates with respect to the fixed plate 10. The anti-backing nail 20 is used to prevent the bone screw 50 from backing up, so that the bone screw 50 is reliably fixed to the fixing plate 10, thereby ensuring the connection effect with the human body.

Referring to fig. 3 and 4, the fixing plate 10 may be made of a steel plate, and the circumferential edges of the fixing plate 10 are curved to adapt to the physiological curvature of the cervical vertebrae. As shown in fig. 3, the front surface 101 of the fixing plate 10 is provided with 2 rows of screw holes 110 penetrating the fixing plate 10. All the screw holes 110 are arranged in an array as a whole. In each row, there are 2 screw holes 110 arranged at intervals. However, it is understood that the number of the screw holes 110 is not limited to 2 rows, but may be 1 row, or may be more than 2 rows. In addition, the number of screw holes 110 in each column is not limited to 2, and may be more than 2. Threaded bore 110 is for mating with bone screw 50. The dimensions of threaded bore 110 are adapted to the dimensions of bone screw 50. The fixing plate 10 is further provided with a through observation window 130. The observation window 130 is positioned between two adjacent columns of the screw holes 110, which is convenient for the doctor to observe. In the present embodiment, the column direction is along the up-down direction in fig. 1, and the row direction is along the left-right direction in fig. 1.

As shown in fig. 3 and 4, in the same row of screw holes 110, a mounting hole 120 penetrating the fixing plate 10 is provided between adjacent screw holes 110. As shown in fig. 1 and 2, the anti-retreat pins 20 are installed in the installation holes 120. The rear end of the anti-retreat pin 20 is connected with a fastening cover 40 for fixing the anti-retreat pin 20 to the fixing plate 10. The anti-back nail 20 is also sleeved with an elastic piece 30. The elastic member 30 is located between the fixing plate 10 and the fastening cap 40, and the fastening cap 40 presses the elastic member 30 against the back surface 102 of the fixing plate 10, so that the elastic member 30 is subjected to a certain axial pressure. Therefore, a certain damping feeling exists between the anti-back nail 20 and the fixing plate 10, so that a certain damping feeling is realized before the bone screw 50 is implanted, and the operation hand feeling of a doctor is further improved.

Referring to fig. 2 to 4, in a direction perpendicular to the front surface 101 and facing the back surface 102, that is, in an axial direction of the mounting hole 120, referring to fig. 2, the mounting hole 120 is a stepped hole, and includes a first large-diameter hole 121, a small-diameter hole 122, and a second large-diameter hole 123 connected in sequence, and their diameters are D1, D2, and D3 in sequence, where D1 and D3 are both larger than D2, that is, two ends of the mounting hole 120 are larger and the middle is smaller. The small-diameter hole 122 has a length L1. As shown in fig. 4, in the same row of screw holes 110, the distance between adjacent screw holes 110 is L2.

As shown in fig. 5 and 6, the anti-retreat nail 20 includes a head 210, and a shaft 220 connected to the head 210. The end face of the head 210 is provided with a drive interface 230 for engagement with a tool to facilitate operation of the drive interface 230 by the tool to rotate the anti-backup nail 20. The driving interface 230 may be in the form of a straight line, a cross, an inner square, an inner hexagon, an inner plum blossom, etc., in this example, an inner hexagon. The end face of the head 210 is circular in shape but is not limited thereto and has a diameter D4. D4 is slightly smaller than D1 so that the head 210 can rotate in the first large diameter hole 121. D4 is greater than L2, i.e., greater than the distance between adjacent screw holes 110. In this way, the head 210 of the anti-back nail 20 may intrude into the area where the bone screw 50 is located, thereby interfering with the bone screw 50, and the head 210 of the anti-back nail 20 can axially limit the bone screw 50, thereby achieving the purpose of preventing the bone screw 50 from loosening.

The tail end of the stem 220 is the tail end of the anti-back nail 20, i.e. the end of the stem 220 away from the head 210. The rod part 220 is embodied as a smooth cylinder having a diameter D5 and a length L3, and is fixedly coupled to the fastening cap 40.

Specifically, as shown in fig. 2 and 6, the head 210 is provided with grooves 211 on two opposite sides in the first direction X (left-right direction in fig. 2), and the grooves 211 are used for avoiding the bone screws 50. The opposite ends 212 of the head 210 in the second direction Y (up-down direction in fig. 2) are used to press the bone screw 50. The second direction Y and the first direction X are perpendicular to each other. As shown in fig. 6, the distance between two grooves 211 on the same anti-back nail 20 is L4, wherein L4 is smaller than the shortest distance L2 between adjacent screw holes 110 in the same column. The shortest distance L2 is a distance between two intersections of the line connecting the centers of the adjacent screw holes 110 and the edge of the adjacent screw holes 110. The distance between the opposite ends 212 of the head 210 in the second direction is D4, and D4 is greater than the distance L2 between the adjacent screw holes 110 in the same row, so that the ends 212 can be used to axially restrain the bone screw 50.

By the above means, the bone screw 50 may be implanted while the recess 211 of the head 210 in the first direction X is facing the screw hole 110. When the two ends 212 of the head 210 in the second direction Y are respectively opposite to the screw holes 110, the bone screws 50 cannot be implanted. In use, the anti-back nail 20 is rotated to align the recess 211 with the screw hole 110, and then the bone screw 50 is implanted. Thereafter, the driving interface 230 is used to rotate the anti-backing nail 20, so that the head 210 of the anti-backing nail 20 axially presses the bone screw 50 at the opposite ends 212 in the second direction, thereby preventing the bone screw 50 from loosening.

In this embodiment, when the head 210 of the anti-back nail 20 is rotated to a position capable of axially limiting the bone screw 50, the head 210 prevents the bone screw 50 from loosening by pressing the bone screw 50. In other embodiments, the head 210 may be tangential to the bone screw 50 when the head 210 is holding the bone screw 50, and the head 210 and the bone screw 50 may interfere with each other to avoid loosening of the bone screw 50.

As shown in fig. 7 and 8, in one example, the elastic member 30 includes an annular sleeve portion 310 and a cylindrical abutting portion 320 connected to the sleeve portion 310. The abutting portion 320 extends obliquely outward from the engaging portion 310, so that the elastic member 30 is formed into a disk shape. The abutment 320 has a larger aperture adjacent the end 212 of the fixation plate 10 than the end 212 of the fixation plate 10. The inside diameter of the sleeve portion 310 is D6, which is slightly larger than the diameter D5 of the stem portion 220 of the anti-back nail 20. The outer diameter of the sleeve portion 310 is D7, wherein D7 is slightly smaller than the inner diameter D3 of the second large-diameter hole 123 of the mounting hole 120.

When the elastic element 30 is installed, the sleeve portion 310 is sleeved on the rod portion 220 of the anti-back nail 20, and the abutting portion 320 extends toward the fixing plate 10. When the fastening cap 40 is coupled to the rod part 220, the abutting part 320 is largely deformed in the axial direction, so that a good damping feeling is provided between the anti-receding nail 20 and the fixing plate 10. In addition, the outer diameter D7 of the sleeve part 310 is smaller than the inner diameter D2 of the second large diameter hole 123 of the mounting hole 120. Accordingly, the elastic member 30 may be at least partially received in the second large-diameter hole 123 of the mounting hole 120, thereby reducing the axial dimension.

Specifically, as shown in fig. 1, 5, and 7, the height of the elastic member 30, i.e., the dimension of the elastic member 30 in the axial direction of the mounting hole 120, is L5, and the height dimension of the fastening cover 40 is L6. The length L3 of the shaft portion 220 of the anti-back nail 20 is slightly smaller than the sum of the three dimensions of the length L1 of the small diameter hole 122 of the mounting hole 120, the height L5 of the elastic element 30 and the height L6 of the fastening cover 40. Therefore, as shown in fig. 2, when the anti-receding nail 20, the elastic element 30 and the fastening cover 40 are assembled and the end surface of the fastening cover 40 is flush with the end surface of the anti-receding nail 20, the elastic element 30 can be ensured to be deformed by a certain axial pressure, so that a good and appropriate damping feeling is provided between the anti-receding nail 20 and the fixing plate 10. And the terminal surface of the fastening cover 40 is flush with the terminal surface of the anti-back nail 20 at this moment, so that the damage to the human body caused by the formation of the concave-convex surface can be avoided. If the length L3 of the stem 220 of the anti-backup nail 20 is slightly smaller than the sum of the length L1 of the small diameter hole 122 of the mounting hole 120, the height L5 of the elastic element 30, and the height L6 of the fastening cap 40, the end face of the fastening cap 40 may be lower than the end face of the anti-backup nail 20, and at this time, the amount of deformation of the elastic element 30 is larger, and the damping feeling is enhanced. The end face of the fastening cover 40 may be lower than the end face of the anti-backing nail 20, that is, in the axial direction of the mounting hole 120, the end face of the anti-backing nail 20 protrudes relative to the end face of the fastening cover 40, and the end face of the anti-backing nail 20 is farther away from the fixing plate 10 than the end face of the fastening cover 40.

The size relationship of L3 to L1, L5, and L6 may not be limited to the above. For example, in other embodiments, L6 may be added, so that after the anti-retreat pin 20, the elastic member 30 and the fastening cover 40 are assembled, the end face of the fastening cover 40 may exceed the end face of the anti-retreat pin 20; for another example, the size of L5 can be increased, and the size of L6 can be decreased, so that the end face of the fastening cover 40 can be flush with the end face of the anti-withdrawal nail 20 after the anti-withdrawal nail 20, the elastic member 30 and the fastening cover 40 are assembled.

The elastic member 30 is not limited to the disk-shaped elastic piece. For example, in other embodiments, the elastic member 30 may only include the annular sleeve portion 310. For another example, in other embodiments, the elastic member 30 may be directly formed of a spring or other parts having elastic deformation capability.

As shown in fig. 9 and 10, the fastening cap 40 includes a tubular structure. The tubular structure of the fastening cap 40 has an outer diameter D8, D8 being slightly larger than the inner diameter D3 of the second large-diameter hole 123 of the mounting hole 120. The inner diameter of the fastening cap 40 is D9, wherein D9 is slightly larger than the diameter of the stem portion 220 of the anti-back nail 20, so that the tubular structure is conveniently sleeved on the stem portion 220. D8 is slightly larger than the inner diameter D3 of the second large diameter hole 123, and the fastening cover 40 does not enter the second large diameter hole 123.

As shown in fig. 2, the tubular structure of the fastening cap 40 is fitted over the stem portion 220. The rod portion 220 is a smooth cylinder, and the rod portion are connected in a laser welding mode. In other embodiments, the fastening cap 40 and the shaft 220 may be fixed together in diameter by riveting, screwing, or the like.

When the spine fixing system 100 of the application is used, the anti-retreat nail 20 is pre-installed in the installation hole 120 in advance, the fastening cover 40 is welded on the rod part 220 of the anti-retreat nail 20 in a laser welding mode, the end face of the fastening cover 40 is flush with the end face of the anti-retreat nail 20, so that the elastic part 30 is compressed and deformed, and the elastic part 30 is subjected to certain axial pressure, so that certain damping is generated between the anti-retreat nail 20 and the fixing plate 10. When the bone screw 50 is implanted, the anti-back nail 20 is rotated to make the recess 211 opposite to the screw hole 110. After the bone screw 50 is implanted, the anti-backing nail 20 is rotated through the driving interface 230, so that the bone screws 50 on both sides of the anti-backing nail 20 are fixed by the two opposite end portions 212 of the head portion 210 in the second direction Y, and the bone screws 50 are prevented from backing.

In the use process of the spine fixing system 100, when the anti-back nail 20 is rotated, a doctor can feel damping, and the operation hand feeling is better. In addition, the above-described damping feeling is generated by the compressed elastic member 30, and the damping function is not required to be realized by the deformation of the anti-retreat pin 20 itself. Therefore, the phenomenon that microcracks appear inside the nail 20 which is prevented from moving back due to overlarge deformation cannot occur, the nail is prevented from being broken in the using process, and then the function failure of the nail which is prevented from moving back is avoided.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are for purposes of illustration only and do not denote a single embodiment.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The utility model provides a vertebra fixing system, includes the fixed plate, the fixed plate is equipped with a plurality of rows and runs through the screw of fixed plate is equipped with between the adjacent screw in same row and runs through the mounting hole of fixed plate, a serial communication port, be equipped with in the mounting hole and prevent moving back the nail, the one end of preventing moving back the nail be connected with will prevent moving back the nail and be fixed in the fastening cover of fixed plate, be equipped with the elastic component in the mounting hole, the elastic component is located the fixed plate with between the fastening cover, the fastening cover will the elastic component compress tightly in the fixed plate.

2. The spinal fixation system of claim 1, wherein the threaded bores receive bone screws; the anti-withdrawal nail comprises a head part and a rod part connected with the head part, wherein grooves are respectively arranged on two opposite sides of the head part in the first direction and are used for avoiding the bone screw; the opposite ends of the head in the second direction can rotate to the position for axially limiting the bone screw, the second direction is perpendicular to the first direction, and the fastening cover is connected to one end, far away from the head, of the rod.

3. The spinal fixation system according to claim 2, wherein the distance between two of the grooves of the same anti-back screw head is less than the shortest distance between adjacent screw holes in the same column to avoid the bone screw; the distance between two opposite end parts of the head part of the anti-withdrawal nail in the second direction is greater than the distance between adjacent screw holes in the same column, so that the two end parts can axially limit the bone screw.

4. The spinal fixation system of claim 3, wherein the head of the anti-back pin compresses the bone screw against the fixation plate from a side of the bone screw facing away from the fixation plate while axially restraining the bone screw.

5. The spinal fixation system of claim 2 wherein the rod portion is a smooth cylinder and the fastening cap includes a tubular structure that fits over the rod portion, the fastening cap being connected to the smooth cylinder.

6. The spinal fixation system of claim 2, wherein a side of the head facing away from the fixation plate is provided with a drive interface for engaging a tool to drive rotation of the anti-backup pin.

7. The spinal fixation system according to claim 2, wherein the mounting hole includes a first large-diameter hole, a small-diameter hole, and a second large-diameter hole connected in series along an axial direction of the mounting hole, the elastic member is partially received in the second large-diameter hole, and a length of the rod portion is smaller than a sum of three dimensions of a length of the small-diameter hole, a height of the elastic member, and a height of the fastening cover in the axial direction; the terminal surface of fastening lid with prevent moving back the terminal surface parallel and level of nail or be less than prevent moving back the terminal surface of nail.

8. The spinal fixation system according to claim 1 or 5, wherein the elastic member includes an annular engaging portion and a cylindrical engaging portion connected to the engaging portion, the engaging portion engages the anti-back nail, the engaging portion extends toward the fixation plate, and an aperture of an end of the engaging portion adjacent to the fixation plate is larger than an aperture of an end of the engaging portion away from the fixation plate.

9. The spinal fixation system of claim 1 or 5, wherein the elastic member is a disk spring or a spring.

10. The spinal fixation system of claim 1, wherein the fixation plate has a viewing window therethrough.

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