Pedicle screw reinforcing device

Abstract

The pedicle screw reinforcing device comprises a screw body, a main hole channel and an auxiliary hole channel are formed in the screw body, the main hole channel comprises a sharing section and a shrinkage limiting section, one end of the auxiliary hole channel is communicated with the sharing section, and the other end of the auxiliary hole channel penetrates through the screw body to be communicated to the outside of the side wall of the screw body; the inner diameter of the auxiliary hole channel is smaller than the inner diameter of the shared section, one end of the shrinkage limiting section is communicated with the shared section, the other end of the shrinkage limiting section is communicated to the outside of the front end of the nail body, the inner diameter of the shared section is D, the inner diameter of the shrinkage limiting section is d, d / D is larger than or equal to 0.1 and smaller than or equal to 0.5, and the inner diameter of the auxiliary hole channel is not smaller than the inner diameter of the shrinkage limiting section. Along the flowing direction of the bone cement in the sharing section, the communicating position of the auxiliary hole channel and the sharing section is located at the upstream of the communicating position of the shrinkage limiting section and the sharing section. The pedicle screw reinforcing device has the advantages that on the premise that the bone cement pedicle screw is guided by the guide wire, the risk that bone cement overflows at the front edge of the vertebral body is reduced.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular to a pedicle screw reinforcement device. Background Art

[0002] Pedicle screw fixation is a common surgical technique in spinal surgery, which restores spinal stability, corrects deformities or promotes fracture healing by implanting pedicle screws into the pedicles and connecting fixation devices (such as metal rods or plates).

[0003] During the pedicle screw fixation process, in order to ensure that the screw trajectory conforms to the preoperative plan, the guide wire will be inserted into the predetermined screw entry point of the pedicle first, and then the guide wire will be passed through the inside of the screw so that the screw can be screwed into place along the guide wire. After the screw is in place, the guide wire will be pulled out. Therefore, a channel that runs through the front end of the screw needs to be formed inside the pedicle screw to facilitate the insertion of the guide wire.

[0004] However, for patients with osteoporosis, their bone density (BMD) decreases, the pedicle bone cortex becomes thinner, and the cancellous bone becomes sparse, which leads to a decrease in the friction between the screw and the bone interface and a decrease in the pull-out resistance. At present, bone cement pedicle screws allow bone cement to be injected into the screw hole during surgery, which is the most effective way to improve the pull-out resistance of the screws in osteoporosis patients during pedicle screw fixation and achieve pedicle screw reinforcement.

[0005] However, for bone cement pedicle screws, when bone cement is injected into the screw hole, it will overflow from the hole at the front end of the screw. In addition, the diffusion of bone cement may cause the risk of bone cement overflowing at the front edge of the vertebral body. Therefore, how to reduce the risk of bone cement overflowing at the front edge of the vertebral body while ensuring that the guidewire guides the bone cement pedicle screw is a problem that needs to be solved urgently. Summary of the invention

[0006] Based on this, it is necessary to provide a pedicle screw reinforcement device. The pedicle screw reinforcement device reduces the risk of bone cement overflow at the front edge of the vertebral body under the premise of satisfying the guide wire to guide the bone cement pedicle screw.

[0007] A pedicle screw reinforcement device comprises a nail body, wherein a main channel and a secondary channel are arranged inside the nail body, the main channel comprises a common section and a shrinkage section, one end of the secondary channel is connected with the common section, the other end of the secondary channel passes through the nail body to be connected to the outside of the nail body side wall, the inner diameter of the secondary channel is smaller than the inner diameter of the common section, one end of the shrinkage section is connected with the common section, the other end of the shrinkage section is connected to the outside of the front end of the nail body, the inner diameter of the common section is D, the inner diameter of the shrinkage section is d, 0.1≤d / D≤0.5, the inner diameter of the secondary channel is not smaller than the inner diameter of the shrinkage section, and along the flow direction of bone cement in the common section, the connection position between the secondary channel and the common section is located upstream of the connection position between the shrinkage section and the common section.

[0008] By adopting the above technical solution, the flow of bone cement inside the nail body depends on the pressure and resistance it is subjected to. Bone cement will more easily flow to the channel with higher pressure but lower resistance. The inner diameter of the constriction section is greatly reduced compared to the common section, so the resistance will increase sharply when the bone cement flows from the common section into the constriction section. The inner diameter of the auxiliary channel is not less than the inner diameter of the constriction section, resulting in the resistance of the auxiliary channel not being greater than the resistance of the constriction section. At the same time, when the bone cement flows in the common section, the pressure will decrease as the flow path is extended. Along the flow direction of bone cement in the common section, the connection position between the auxiliary channel and the common section is located upstream of the connection position between the constriction section and the common section, then the pressure at the connection position between the auxiliary channel and the common section will be greater than the pressure at the connection position between the constriction section and the common section. Therefore, when the bone cement in the common section is obstructed by the constriction section, it will be easier to flow out of the auxiliary channel under pressure, and then the bone cement flowing out of the constriction section will be greatly reduced. The contraction section is connected to the outside of the front end of the nail body, and the auxiliary channel is connected to the outside of the side wall of the nail body. Therefore, the bone cement flowing out of the front end of the nail body will be greatly reduced, and the bone cement flowing out of the side wall of the nail body will be greatly increased, thereby reducing the risk of bone cement overflowing at the leading edge of the vertebral body. However, the existence of the contraction section allows the guide wire to enter the common section through the contraction section, and during the operation, the guide wire first enters the contraction section and then enters the common section. Therefore, the guide wire can be used normally to meet the function of the guide wire guiding the bone cement pedicle screw. Ultimately, the pedicle screw reinforcement device can reduce the risk of bone cement overflowing at the leading edge of the vertebral body while meeting the premise of the guide wire guiding the bone cement pedicle screw.

[0009] In addition, the amount of bone cement flowing out from the side wall of the screw body will increase significantly, which can increase the wrapping of the bone cement on the screw body, thereby enhancing the bonding force between the screw body and the vertebra, improving the pull-out resistance, and achieving further reinforcement of the pedicle screw.

[0010] In one embodiment, the main channel also includes a guide section, one end of the guide section is connected to an end of the limiting section away from the common section, and the other end of the guide section passes through the nail body to be connected to the outside of the front end of the nail body, and the aperture of the guide section gradually decreases from the end of the guide section connected to the outside of the front end of the nail body to the end of the guide section connected to the limiting section.

[0011] By adopting the above technical solution, the inner diameter of the limiting section is greatly reduced compared to the common section, which makes it more difficult to directly insert the guide wire into the limiting section, affecting the operation speed during the operation. The guide section can guide the guide wire into the limiting section, and then enter the common section through the limiting section, thereby speeding up the operation speed of inserting the guide wire into the nail body.

[0012] In one embodiment, the shrinkage section and the common section at least partially overlap along the axial direction of the nail body, and a buffer space is formed between the outer wall of the shrinkage section and the inner wall of the common section.

[0013] In one embodiment, the outer diameter of the outer wall of the overlapping portion of the limiting section and the common section gradually decreases from the end where the limiting section is connected to the outside of the front end of the nail body to the end where the limiting section is connected to the common section.

[0014] By adopting the above technical solution, the buffer space is set so that bone cement needs to fill the buffer space before entering the constriction section, thereby reducing the amount of bone cement entering the constriction section. The bone cement is first guided to the buffer space through the outer wall of the overlapping part of the constriction section and the common section, thereby further reducing the amount of bone cement entering the constriction section. Ultimately, the amount of bone cement entering the constriction section is greatly reduced, and the amount of bone cement naturally entering the auxiliary channel will be greatly increased, thereby reducing the risk of bone cement overflowing at the front edge of the vertebral body.

[0015] In one embodiment, the secondary channel includes a first hole position, and the first hole position is connected to the buffer space of the common section.

[0016] By adopting the above technical solution, the first hole allows the bone cement in the buffer space to flow out from the first hole to the outside of the side wall of the nail body, so that the buffer space is difficult to be filled, and naturally it is more difficult for bone cement to enter the restricted section, thereby reducing the risk of bone cement overflow at the front edge of the vertebral body.

[0017] In one embodiment, a plane perpendicular to the axial direction of the nail body and passing through the apex of the front end of the nail body is used as a reference plane, the point closest to the reference plane at one end of the first hole connected to the cache space is X, the point closest to the reference plane in the cache space is Y, and the distance from X to the reference plane is not greater than the distance from Y to the reference plane.

[0018] In one embodiment, the inner diameter of the first hole gradually decreases from one end of the first hole connected to the outside of the side wall of the nail body to one end of the first hole connected to the buffer space.

[0019] By adopting the above technical solution, the resistance of bone cement in the buffer space when flowing to the first hole is reduced, making it difficult to fill the buffer space, and naturally it is more difficult for bone cement to enter the restricted section, thereby reducing the risk of bone cement overflow at the front edge of the vertebral body.

[0020] In one of the embodiments, along the axial direction of the first hole, the first hole gradually moves away from the reference surface from one end where the first hole is connected to the outside of the side wall of the nail body to one end where the first hole is connected to the cache space.

[0021] By adopting the above technical solution, the bending degree of bone cement flowing from the common section to the first hole is weaker, thereby reducing the resistance of the first hole to the bone cement, making it easier for the bone cement to flow to the first hole.

[0022] In one embodiment, the secondary channel includes a second hole position, with a plane perpendicular to the axial direction of the nail body and passing through the apex of the front end of the nail body as a reference plane, the distance from the second hole position to the reference plane is greater than the distance from the first hole position to the reference plane, the inner diameter of the second hole position gradually decreases from one end where the second hole position is connected to the outside of the side wall of the nail body to one end where the second hole position is connected to the common section, and the distance between the second hole position and the reference plane remains unchanged from one end where the second hole position is connected to the outside of the side wall of the nail body to one end where the second hole position is connected to the common section.

[0023] By adopting the above technical solution, the distance from the second hole to the reference surface is greater than the distance from the first hole to the reference surface, so the pressure at the position where the second hole is connected to the common section will be greater than the pressure at the position where the first hole is connected to the common section. However, the distance between the second hole and the reference surface remains unchanged from the end where the second hole is connected to the outside of the side wall of the nail body to the end where the second hole is connected to the common section, so the resistance of the second hole to the bone cement will be greater than the resistance of the first hole to the bone cement, so that the bone cement can flow out evenly from the first hole and the second hole under the dual effects of pressure and resistance, increasing the uniformity of bone cement distribution on the side wall of the nail body.

[0024] In one embodiment, the secondary channel includes a third hole position, the distance from the third hole position to the reference surface is greater than the distance from the second hole position to the reference surface, the inner diameter of the third hole position remains unchanged from one end where the third hole position is connected to the outside of the side wall of the nail body to one end where the third hole position is connected to the common section, and the distance between the third hole position and the reference surface remains unchanged from one end where the third hole position is connected to the outside of the side wall of the nail body to one end where the third hole position is connected to the common section.

[0025] By adopting the above technical solution, the distance from the third hole to the reference surface is greater than the distance from the second hole to the reference surface, so the pressure at the connection position between the second hole and the common section will be greater than the pressure at the connection position between the first hole and the common section. However, the inner diameter of the third hole remains unchanged from the end where the third hole is connected to the outside of the side wall of the nail body to the end where the third hole is connected to the common section, and the distance between the third hole and the reference surface remains unchanged from the end where the third hole is connected to the outside of the side wall of the nail body to the end where the third hole is connected to the common section, so the resistance of the third hole to the bone cement will be greater than the resistance of the second hole to the bone cement, so that the bone cement can flow out evenly from the second hole and the third hole under the dual effects of pressure and resistance, thereby increasing the uniformity of bone cement distribution on the side wall of the nail body.

[0026] In one embodiment, the pedicle screw reinforcement device also includes a nail tail, a nut and a connecting rod, one end of the nail tail cooperates with the nail body, the nail tail is provided with a connected avoidance groove and an assembly groove, the avoidance groove penetrates the nail tail along a direction perpendicular to the axial direction of the nail body, the assembly groove penetrates the other end of the nail tail along the axial direction of the nail body, the nut is threadedly connected in the assembly groove, and the rear end of the nail body is provided with a first screw groove connected to an end of the common section away from the shrinkage section, The connecting rod comprises a connecting portion and at least two limiting portions, at least two of the limiting portions are connected to two ends of the connecting portion, a projection of the connecting portion along the axial direction of the connecting portion is located within the projection range of the limiting portion along the axial direction of the connecting portion, at least parts of the two ends of the limiting portion along the axial direction of the nail body are spherical, and the outer diameter of the limiting portion is smaller than the maximum diameter of the avoidance groove but larger than the minimum inner diameter of the first screw groove, When the nut is threadedly connected to the assembly groove, the nut and the nail body respectively contact the spherical surfaces at both ends of the limiting part along the axial direction of the nail body, and the minimum distance between the nut and the rear end of the nail body is smaller than the maximum distance between the two ends of the limiting part along the axial direction of the nail body.

[0027] By adopting the above technical solution, when the nut is in the preset position, that is, the minimum distance between the nut and the rear end of the nail body is less than the maximum distance between the two ends of the limiting part along the axial direction of the nail body, the limiting part will not be able to escape from the assembly groove. At this time, when the nut and the rear end of the nail body do not exert a large pressure on the limiting part, the limiting part can rotate relative to the nut and the nail body, thereby allowing the relative position between the two nail bodies to move within a preset range, which is more in line with the needs of human activities.

[0028] In one embodiment, the thread of the assembly groove is an internal thread, and the thread of the nut is an external thread. The thread of the assembly groove is configured to have a minimum distance from the rear end of the nail body so that the nut and the nail body are in spherical contact with the limiting portion at both ends along the axial direction of the nail body.

[0029] By adopting the above technical solution and utilizing the thread setting of the assembly groove, it is possible to avoid the control nut and the nail body from exerting a large pressure on the limiting portion during the operation, thereby allowing the relative position of the two nail bodies to move within a preset range after the operation, which is more in line with the needs of human activities.

[0030] In one of the embodiments, the nut is provided with a second screw groove, the second screw groove passes through the nut, and the outer diameter of the limiting portion is greater than the minimum inner diameter of the second screw groove.

[0031] By adopting the above technical solution, the second screw groove and the first screw groove cooperate with each other to limit the limiting part from leaving the assembly groove, which is more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A schematic diagram of the structure of the combined use of the pedicle screw reinforcement device provided in this application; Figure 2 A cross-sectional view of the pedicle screw reinforcement device provided in this application; Figure 3 for Figure 2 A magnified image of area A; Figure 4 for Figure 2 Magnified view of area B.

[0034] 1. The screw thread of the embodiment of the present invention is as follows: 100, screw; 110, nail body; 111, rotating part; 111a, rotating surface; 111b, positioning surface; 111c, first screw groove; 112, insertion part; 113, main channel; 113a, common section; 113b, limiting section; 113c, guide section; 114, auxiliary channel; 114a, first hole position; 114b, second hole position; 114c, third hole position; 120, nail tail; 121, avoidance groove; 122, assembly groove; 123, positioning groove; 130, fixing sleeve; 131, first positioning part; 132, second positioning part; 200, connecting rod; 210, connecting part; 220, limiting part; 300, nut; 310, second screw groove; 400, buffer space; 500, reference surface. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0036] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, a first feature being “above”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0040] Reference Figure 1-4The present application provides a pedicle screw reinforcement device, comprising a screw 100, a connecting rod 200 and a nut 300. The screw 100 is implanted in the pedicle, and the nut 300 cooperates with the screw 100 to limit the connecting rod 200 from being separated from the screw 100. The connecting rod 200 is used to connect multiple screws 100 implanted in different pedicles.

[0041] The screw 100 includes a nail body 110, a nail tail 120, and a fixing sleeve 130. The fixing sleeve 130 is used to limit the separation of the nail body 110 and the nail tail 120 and to allow the nail body 110 to rotate relative to the nail tail 120, thereby facilitating the assembly of the connecting rod 200 and the screw 100 during surgery. It is understandable that the fixing sleeve 130 can also be eliminated, and the nail body 110 and the nail tail 120 can be set to be connected as one piece, or the nail body 110 and the nail tail 120 can be fixed by other means, so that the nail body 110 can no longer rotate relative to the nail tail 120, but in this way, the difficulty of assembling the connecting rod 200 and the screw 100 during surgery will be increased.

[0042] The nail body 110 includes an integrally connected rotating portion 111 and an inserting portion 112. The rotating portion 111 is located at the rear end of the nail body 110, and the rotating portion 111 and the inserting portion 112 are coaxially designed, but the projection of the inserting portion 112 along the axial direction of the nail body 110 is located within the projection range of the rotating portion 111 along the axial direction of the nail body 110.

[0043] The outer surface of the rotating part 111 includes a rotating surface 111a and a positioning surface 111b. The rotating surface 111a is a spherical surface, and the positioning surface 111b is a plane or a spherical surface. When the positioning surface 111b is a spherical surface, the curvature of the positioning surface 111b should be smaller than the curvature of the rotating surface 111a. The positioning surface 111b and the insertion part 112 are located at the two ends of the axial direction of the rotating part 111, and the two ends of the rotating surface 111a are respectively connected to the rotating surface 111a and the insertion part 112. The rotating part 111 is provided with a first screw groove 111c extending toward the insertion part 112 on the positioning surface 111b, and the first screw groove 111c and the rotating part 111 are coaxially designed.

[0044] The insertion part 112 is rod-shaped as a whole. The rear end of the insertion part 112 is connected to the rotating part 111, and the front end of the insertion part 112 forms a tip for easy insertion into the pedicle. The outer surface of the insertion part 112 is provided with an external thread.

[0045] A main hole 113 and a secondary hole 114 are provided inside the nail body 110. The main hole 113 is distributed in the rotating part 111 and the inserting part 112, and the secondary hole 114 is distributed in the inserting part 112. The main hole 113 is coaxially designed with the first screw groove 111c. One end of the main hole 113 is connected to the first screw groove 111c, and the other end of the main hole 113 passes through the front end of the inserting part 112 to connect to the outside of the front end of the nail body 110. One end of the secondary hole 114 is connected to the main hole 113, and the other end of the secondary hole 114 passes through the side wall of the inserting part 112 to connect to the outside of the side wall of the nail body 110.

[0046] The main channel 113 includes a common section 113a, a limiting section 113b and a guide section 113c, and the common section 113a, the limiting section 113b and the guide section 113c are coaxially designed. One end of the limiting section 113b is connected to one end of the common section 113a, and the other end of the limiting section 113b is connected to one end of the guide section 113c. The other end of the common section 113a is connected to the first screw groove 111c, and the other end of the guide section 113c passes through the nail body 110 to connect to the outside of the front end of the insertion portion 112. The inner diameter of the common section 113a is larger than the inner diameter of the limiting section 113b, and the inner diameter D of the common section 113a and the inner diameter d of the limiting section 113b satisfy 0.1≤d / D≤0.5. Preferably, d / D is 0.1, 0.2, 0.3, 0.4, 0.5. The inner diameter of the constriction section 113b is greatly reduced compared to the common section 113a, so the resistance will increase sharply when the bone cement flows from the common section 113a into the constriction section 113b. The aperture of the guide section 113c gradually decreases from the end where the guide section 113c is connected to the outside of the front end of the insertion part 112 to the end where the guide section 113c is connected to the constriction section 113b. The aperture of the end where the guide section 113c is connected to the outside of the front end of the insertion part 112 is not larger than the inner diameter of the common section 113a. Preferably, the aperture of the end where the guide section 113c is connected to the outside of the front end of the insertion part 112 is equal to the inner diameter of the common section 113a. The inner diameter of the constriction section 113b is greatly reduced compared to the common section 113a, which makes it more difficult to directly insert the guide wire into the constriction section 113b, affecting the operation speed during the operation. The guide section 113c can guide the guide wire to be inserted into the limiting section 113b, and then enter the common section 113a through the limiting section 113b, thereby accelerating the operation speed of inserting the guide wire into the interior of the nail body 110. The limiting section 113b and the common section 113a overlap at least partially along the axial direction of the nail body 110, and a buffer space 400 is formed between the outer wall of the limiting section 113b and the inner wall of the common section 113a. The outer diameter of the outer wall of the overlapping part of the limiting section 113b and the common section 113a gradually decreases from the end of the limiting section 113b connected to the guide section 113c to the end of the limiting section 113b connected to the common section 113a. The setting of the buffer space 400 requires that the bone cement needs to fill the buffer space 400 before entering the limiting section 113b, thereby reducing the bone cement entering the limiting section 113b. The outer wall of the overlapping part of the limiting section 113b and the common section 113a guides the bone cement to the buffer space 400 first, thereby further reducing the amount of bone cement entering the limiting section 113b. Finally, the amount of bone cement entering the limiting section 113b is greatly reduced, and the amount of bone cement naturally entering the auxiliary channel 114 is greatly increased, thereby reducing the risk of bone cement overflowing at the front edge of the vertebral body.

[0047] The auxiliary channel 114 is connected to the main channel 113 by connecting to the common section 113a. The inner diameter of the auxiliary channel 114 is smaller than the inner diameter of the common section 113a, but the inner diameter of the auxiliary channel 114 is not smaller than the inner diameter of the contraction section 113b. Along the flow direction of bone cement in the common section 113a, the connection position of the auxiliary channel 114 and the common section 113a is located upstream of the connection position of the contraction section 113b and the common section 113a. The flow of bone cement inside the nail body 110 depends on the pressure and resistance it is subjected to. Bone cement will more easily flow to the channel with higher pressure but lower resistance. The inner diameter of the auxiliary channel 114 is not smaller than the inner diameter of the contraction section 113b, resulting in the resistance of the auxiliary channel 114 not being greater than the resistance of the contraction section 113b. At the same time, when bone cement flows in the common section 113a, the pressure will decrease as the flow path is extended. Along the flow direction of bone cement in the common section 113a, the position where the auxiliary channel 114 connects with the common section 113a is located upstream of the position where the constriction section 113b connects with the common section 113a, so the pressure at the position where the auxiliary channel 114 connects with the common section 113a will be greater than the pressure at the position where the constriction section 113b connects with the common section 113a. Therefore, when the bone cement in the common section 113a is blocked by the constriction section 113b, it will be easier to flow out of the auxiliary channel 114 under the action of pressure, so the bone cement flowing out of the constriction section 113b will be greatly reduced. The constriction section 113b is connected to the outside of the front end of the nail body 110, and the auxiliary channel 114 is connected to the outside of the side wall of the insertion part 112, so the bone cement flowing out of the front end of the nail body 110 will be greatly reduced, and the bone cement flowing out of the side wall of the insertion part 112 will be greatly increased, thereby reducing the risk of bone cement overflowing at the front edge of the vertebral body. However, the existence of the constriction section 113b allows the guide wire to enter the common section 113a through the constriction section 113b, and during the operation, the guide wire first enters the constriction section 113b and then enters the common section 113a, so the guide wire can be used normally to meet the function of the guide wire guiding the bone cement pedicle screw. Ultimately, the pedicle screw reinforcement device can reduce the risk of bone cement overflow at the front edge of the vertebral body while meeting the premise of the guide wire guiding the bone cement pedicle screw.

[0048] In addition, the amount of bone cement flowing out from the side wall of the insertion portion 112 will increase significantly, which can increase the wrapping of the bone cement on the nail body 110, thereby enhancing the bonding force between the nail body 110 and the vertebra, improving the anti-pullout ability, and achieving further reinforcement of the pedicle screw.

[0049] The auxiliary hole 114 includes a first hole 114a, a second hole 114b and a third hole 114c. Taking the plane perpendicular to the axial direction of the nail body 110 and passing through the front end vertex of the insertion portion 112 as the reference plane 500, the distance from the first hole 114a to the reference plane 500 is smaller than the distance from the second hole 114b to the reference plane 500, and the distance from the second hole 114b to the reference plane 500 is smaller than the distance from the third hole 114c to the reference plane 500. The projection angle of the axis of the first hole 114a and the axis of the second hole 114b in the reference plane 500 is 90°, and the projection angle of the axis of the second hole 114b and the axis of the third hole 114c in the reference plane 500 is 90°. The minimum inner diameter of the first hole 114a, the minimum inner diameter of the second hole 114b and the minimum inner diameter of the third hole 114c are all equal. The first hole 114a and the common section 113a are connected to the buffer space 400. The first hole 114a allows the bone cement in the buffer space 400 to flow out from the first hole 114a to the outside of the side wall of the nail body 110, so that the buffer space 400 is difficult to be filled, and naturally the bone cement is more difficult to enter the limiting section 113b, thereby reducing the risk of bone cement overflowing at the front edge of the vertebral body. The point X at one end of the first hole 114a connected to the buffer space 400 is closest to the reference plane 500, and the point Y at the buffer space 400 is closest to the reference plane 500. The distance from X to the reference plane 500 is not greater than the distance from Y to the reference plane 500. Figure 3As shown, at this time, X and Y coincide, that is, the distance from X to the reference plane 500 and the distance from Y to the reference plane 500 are equal. The inner diameter of the first hole 114a gradually decreases from the end where the first hole 114a is connected to the outside of the side wall of the insertion portion 112 to the end where the first hole 114a is connected to the buffer space 400, thereby reducing the resistance of the bone cement in the buffer space when flowing to the first hole 114a, so that the buffer space 400 is difficult to be filled, and naturally the bone cement is more difficult to enter the constriction section 113b, thereby reducing the risk of bone cement overflowing at the front edge of the vertebral body. Along the axial direction of the first hole 114a, the first hole 114a gradually moves away from the reference plane 500 from the end where the first hole 114a is connected to the outside of the side wall of the insertion portion 112 to the end where the first hole 114a is connected to the buffer space 400. The degree of bending of the bone cement flowing from the common section 113a to the first hole 114a is relatively weak, thereby reducing the resistance of the first hole 114a to the bone cement, making it easier for the bone cement to flow to the first hole 114a. The inner diameter of the second hole 114b gradually decreases from the end where the second hole 114b is connected to the outside of the side wall of the insertion portion 112 to the end where the second hole 114b is connected to the common section 113a, but the distance between the second hole 114b and the reference surface 500 remains unchanged from the end where the second hole 114b is connected to the outside of the side wall of the insertion portion 112 to the end where the second hole 114b is connected to the common section 113a. If the distance from the second hole 114b to the reference surface 500 is greater than the distance from the first hole 114a to the reference surface 500, then the pressure at the position where the second hole 114b is connected to the common section 113a will be greater than the pressure at the position where the first hole 114a is connected to the common section 113a. However, the distance between the second hole 114b and the reference surface 500 remains unchanged from the end where the second hole 114b is connected to the outside of the side wall of the nail body 110 to the end where the second hole 114b is connected to the common section 113a, so that the resistance of the second hole 114b to the bone cement will be greater than the resistance of the first hole 114a to the bone cement, so that the bone cement can flow out from the first hole 114a and the second hole 114b evenly under the dual effects of pressure and resistance, thereby increasing the uniformity of the distribution of the bone cement on the side wall of the nail body 110. The inner diameter of the third hole 114c remains unchanged from the end where the third hole 114c is connected to the outside of the side wall of the insertion portion 112 to the end where the third hole 114c is connected to the common section 113a, and the distance between the third hole 114c and the reference surface 500 remains unchanged from the end where the third hole 114c is connected to the outside of the side wall of the insertion portion 112 to the end where the third hole 114c is connected to the common section 113a. The distance from the third hole 114c to the reference surface 500 is greater than the distance from the second hole 114b to the reference surface 500, so the pressure at the connection position between the second hole 114b and the common section 113a will be greater than the pressure at the connection position between the first hole 114a and the common section 113a.However, the inner diameter of the third hole 114c remains unchanged from one end where the third hole 114c is connected to the outside of the side wall of the nail body 110 to one end where the third hole 114c is connected to the common section 113a, and the distance between the third hole 114c and the reference surface 500 remains unchanged from one end where the third hole 114c is connected to the outside of the side wall of the nail body 110 to one end where the third hole 114c is connected to the common section 113a. Then, the resistance of the third hole 114c to bone cement will be greater than the resistance of the second hole 114b to bone cement, so that the bone cement can flow out evenly from the second hole 114b and the third hole 114c under the dual effects of pressure and resistance, thereby increasing the uniformity of the distribution of bone cement on the side wall of the nail body 110.

[0050] The nail tail 120 is provided with a connected avoidance groove 121 and an assembly groove 122, and the diameter of the avoidance groove 121 is smaller than the diameter of the assembly groove 122. The avoidance groove 121 penetrates the nail tail 120 along the direction perpendicular to the axial direction of the nail body 110, and the diameter of the avoidance groove 121 remains unchanged along the axial direction of the nail body 110. The assembly groove 122 penetrates both ends of the nail tail 120 along the axial direction of the nail body 110. When the nail body 110 and the nail tail 120 are arranged to be connected as one piece, the assembly groove 122 only penetrates the end of the nail tail 120 away from the nail body 110 along the axial direction of the nail body 110. In the case where the assembly groove 122 penetrates both ends of the nail tail 120 along the axial direction of the nail body 110, the diameter of the assembly groove 122 first remains unchanged and then gradually decreases from one end of the nail tail 120 to the other end along the axial direction of the nail body 110. The maximum outer diameter of the rotating part 111 is located on the rotating surface 111a, and the maximum outer diameter of the rotating surface 111a is smaller than the maximum diameter of the assembly groove 122 but larger than the minimum diameter of the assembly groove 122. The rotating part 111 is located in the assembly groove 122 and in the part of the assembly groove 122 where the diameter gradually decreases. The rotating surface 111a of the rotating part 111 contacts the inner wall of the assembly groove 122. The inner wall of the assembly groove 122 is provided with an internal thread, and the nut 300 is provided with an external thread. The nut 300 is threadedly connected to the assembly groove 122 through the cooperation of the internal thread and the external thread. The nail tail 120 is provided with a clamping groove 123 on the inner wall of the assembly groove 122, which is connected to the assembly groove 122, and the fixing sleeve 130 includes a first clamping portion 131 and a second clamping portion 132 connected to each other. The first locking portion 131 is located in the assembly groove 122 and wraps the rotating surface 111a of the rotating portion 111. The second locking portion 132 is locked in the locking groove 123, so that the fixing sleeve 130 is restricted from escaping from the locking groove 123 through the nail tail 120, and the fixing sleeve 130 restricts the rotating portion 111 from escaping from the assembly groove 122.

[0051] The connecting rod 200 includes a connecting portion 210 and at least two limiting portions 220. At least two limiting portions 220 are connected to both ends of the connecting portion 210. The projection of the connecting portion 210 along the axial direction of the connecting portion 210 is located within the projection range of the limiting portion 220 along the axial direction of the connecting portion 210. Both ends of the limiting portion 220 along the axial direction of the nail body 110 are at least partially spherical. The outer diameter of the connecting portion 210 is smaller than the maximum diameter of the avoidance groove 121. The outer diameter of the limiting portion 220 is smaller than the maximum diameter of the avoidance groove 121 but larger than the minimum inner diameter of the first screw groove 111c, so that it is convenient to insert the connecting rod 200 into the avoidance groove 121 from a direction perpendicular to the axial direction of the nail body 110 during surgery. It can be understood that the outer diameter of the limiting portion 220 can also be larger than the maximum diameter of the avoidance groove 121 but still needs to be smaller than the maximum diameter of the assembly groove 122, so as to ensure that the limiting portion 220 can enter the assembly groove 122 from the end of the assembly groove 122 with a larger diameter. When the nut 300 is threadedly connected to the assembly groove 122, the nut 300 and the rotating part 111 are in contact with the spherical surfaces of the two ends of the limiting part 220 along the axial direction of the nail body 110, respectively, and the minimum distance between the nut 300 and the rotating part 111 is less than the maximum distance between the two ends of the limiting part 220 along the axial direction of the nail body 110. In the existing pedicle screw reinforcement device, the nut 300 and the nail body 110 need to squeeze the connecting rod 200 to prevent the connecting rod 200 from being separated from the screw 100 and losing the stabilizing effect on the spine. However, in this way, the patient has a problem of limited movement after the operation. In the present application, when the nut 300 is located at the preset position, that is, the minimum distance between the nut 300 and the rear end of the nail body 110 is less than the maximum distance between the two ends of the limiting part 220 along the axial direction of the nail body 110, the limiting part 220 will not be able to separate from the assembly groove 122. At this time, when the rear ends of the nut 300 and the nail body 110 do not exert a large extrusion on the limiting portion 220, the limiting portion 220 can rotate relative to the nut 300 and the nail body 110, thereby allowing the relative position between the two nail bodies 110 to move within a preset range, thereby more in line with the needs of human activities, improving the patient's mobility after the operation, while still stabilizing the spine. The thread of the assembly groove 122 is configured to have a minimum distance from the positioning surface 111b to meet the spherical contact between the nut 300 and the nail body 110 and the limiting portion 220 along the axial direction of the nail body 110. The thread setting of the assembly groove 122 is used to avoid the control of the nut 300 and the nail body 110 to exert a large extrusion on the limiting portion 220 during the operation, thereby allowing the relative position between the two nail bodies 110 to move within a preset range after the operation, thereby more in line with the needs of human activities. The nut 300 is provided with a second screw groove 310, which penetrates the nut 300, and the outer diameter of the limiting portion 220 is greater than the minimum inner diameter of the second screw groove 310. The second screw groove 310 and the first screw groove 111c cooperate to jointly limit the limiting portion 220 from the assembly groove 122, which is more reliable.

[0052] The length of the connecting part 210, the number of the connecting parts 210 and the number of the limiting parts 220 need to be determined according to the actual situation of the patient. For example, when the patient needs to implant three screws 100, the connecting rod 200 needs to include two connecting parts 210 and three limiting parts 220. The limiting parts 220 and the connecting parts 210 are connected in an alternating manner. The connecting rod 200 can be prefabricated in different specifications according to the situations that are often needed during the operation, and the appropriate specifications can be selected during the operation, thereby avoiding temporary production during the operation.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A pedicle screw reinforcement device, characterized in that: The invention comprises a nail body (110), wherein a main hole (113) and a secondary hole (114) are arranged inside the nail body (110), wherein the main hole (113) comprises a common section (113a) and a shrinkage section (113b), wherein one end of the secondary hole (114) is connected to the common section (113a), and the other end of the secondary hole (114) passes through the nail body (110) to be connected to the outside of the side wall of the nail body (110), wherein the inner diameter of the secondary hole (114) is smaller than the inner diameter of the common section (113a), and one end of the shrinkage section (113b) is connected to the common section (113a). The common section (113a) is connected to the limiting section (113b), the other end of the limiting section (113b) is connected to the outside of the front end of the nail body (110), the inner diameter of the common section (113a) is D, the inner diameter of the limiting section (113b) is d, 0.1≤d / D≤0.5, the inner diameter of the auxiliary channel (114) is not less than the inner diameter of the limiting section (113b), and along the flow direction of bone cement in the common section (113a), the connecting position of the auxiliary channel (114) and the common section (113a) is located upstream of the connecting position of the limiting section (113b) and the common section (113a).

2. A pedicle screw reinforcement device according to claim 1, characterized in that: The main channel (113) further comprises a guide section (113c), one end of which is connected to an end of the limiting section (113b) away from the common section (113a), and the other end of which passes through the nail body (110) to be connected to the outside of the front end of the nail body (110), and the aperture of the guide section (113c) gradually decreases from the end of the guide section (113c) connected to the outside of the front end of the nail body (110) to the end of the guide section (113c) connected to the limiting section (113b).

3. A pedicle screw reinforcement device according to claim 1, characterized in that: The limiting section (113b) and the common section (113a) at least partially overlap along the axial direction of the nail body (110), and a buffer space (400) is formed between the outer wall of the limiting section (113b) and the inner wall of the common section (113a). The outer diameter of the outer wall of the overlapping portion of the limiting section (113b) and the common section (113a) gradually decreases from the end of the limiting section (113b) connected to the outside of the front end of the nail body (110) to the end of the limiting section (113b) connected to the common section (113a).

4. A pedicle screw reinforcement device according to claim 3, characterized in that: The secondary hole channel (114) comprises a first hole position (114a), and the first hole position (114a) is connected to the buffer space (400) of the common section (113a).

5. A pedicle screw reinforcement device according to claim 4, characterized in that: A plane perpendicular to the axial direction of the nail body (110) and passing through the front end vertex of the nail body (110) is used as a reference plane (500), the point X at one end of the first hole position (114a) connected to the buffer space (400) closest to the reference plane (500), the point Y at the buffer space (400) closest to the reference plane (500), and the distance from X to the reference plane (500) is not greater than the distance from Y to the reference plane (500); and / or, The inner diameter of the first hole (114a) gradually decreases from one end where the first hole (114a) is connected to the outside of the side wall of the nail body (110) to one end where the first hole (114a) is connected to the buffer space (400); and / or, Along the axial direction of the first hole position (114a), the first hole position (114a) gradually moves away from the reference surface (500) from one end where the first hole position (114a) is connected to the outside of the side wall of the nail body (110) to one end where the first hole position (114a) is connected to the cache space (400).

6. A pedicle screw reinforcement device according to claim 5, characterized in that: The secondary hole (114) includes a second hole position (114b), with a plane perpendicular to the axial direction of the nail body (110) and passing through the front end vertex of the nail body (110) as a reference plane (500), the distance from the second hole position (114b) to the reference plane (500) is greater than the distance from the first hole position (114a) to the reference plane (500), the inner diameter of the second hole position (114b) gradually decreases from the end where the second hole position (114b) is connected to the outside of the side wall of the nail body (110) to the end where the second hole position (114b) is connected to the common section (113a), and the distance between the second hole position (114b) and the reference plane (500) remains unchanged from the end where the second hole position (114b) is connected to the outside of the side wall of the nail body (110) to the end where the second hole position (114b) is connected to the common section (113a).

7. A pedicle screw reinforcement device according to claim 6, characterized in that: The auxiliary hole (114) includes a third hole position (114c), the distance between the third hole position (114c) and the reference surface (500) is greater than the distance between the second hole position (114b) and the reference surface (500), the inner diameter of the third hole position (114c) remains unchanged from one end where the third hole position (114c) is connected to the outside of the side wall of the nail body (110) to one end where the third hole position (114c) is connected to the common section (113a), and the distance between the third hole position (114c) and the reference surface (500) remains unchanged from one end where the third hole position (114c) is connected to the outside of the side wall of the nail body (110) to one end where the third hole position (114c) is connected to the common section (113a).

8. The pedicle screw reinforcement device according to claim 1, characterized in that: The pedicle screw (100) reinforcement device also includes a nail tail (120), a nut (300) and a connecting rod (200). One end of the nail tail (120) cooperates with the nail body (110). The nail tail (120) is provided with a connected avoidance groove (121) and an assembly groove (122). The avoidance groove (121) penetrates the nail tail (120) along a direction perpendicular to the axial direction of the nail body (110). The assembly groove (122) penetrates the other end of the nail tail (120) along the axial direction of the nail body (110). The nut (300) is threadedly connected in the assembly groove (122). The rear end of the nail body (110) is provided with a first screw groove (111c) connected to an end of the common section (113a) away from the shrinkage section (113b). The connecting rod (200) comprises a connecting portion (210) and at least two limiting portions (220), wherein at least two limiting portions (220) are connected to two ends of the connecting portion (210), a projection of the connecting portion (210) along the axial direction of the connecting portion (210) is located within the projection range of the limiting portion (220) along the axial direction of the connecting portion (210), two ends of the limiting portion (220) along the axial direction of the nail body (110) are at least partially spherical, an outer diameter of the limiting portion (220) is smaller than the maximum diameter of the avoidance groove (121) but larger than the minimum inner diameter of the first screw groove (111c), When the nut (300) is threadedly connected to the assembly groove (122), the nut (300) and the nail body (110) are respectively in contact with the spherical surfaces of the limiting portion (220) at both ends along the axial direction of the nail body (110), and the minimum distance between the rear end of the nut (300) and the nail body (110) is smaller than the maximum distance between the two ends of the limiting portion (220) along the axial direction of the nail body (110).

9. A pedicle screw reinforcement device according to claim 8, characterized in that: The thread of the assembly groove (122) is an internal thread, and the thread of the nut (300) is an external thread. The thread of the assembly groove (122) is configured to have a minimum distance from the rear end of the nail body (110) so that the nut (300) and the nail body (110) are in spherical contact with the two ends of the limiting portion (220) along the axial direction of the nail body (110).

10. The pedicle screw reinforcement device according to claim 8, characterized in that: The nut (300) is provided with a second screw groove (310), the second screw groove (310) passes through the nut (300), and the outer diameter of the limiting portion (220) is greater than the minimum inner diameter of the second screw groove (310).

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