Pedicle screw

Abstract

The pedicle screw comprises a screw rod and a spherical head connected with the rear end of the screw rod, the interior of the screw rod is hollow, and a hole channel coaxial with the screw rod is formed; a first threaded section and a second threaded section are sequentially arranged outside the screw rod in the direction from the rear end to the front end of the screw rod; the thread pitch of the first thread section is smaller than that of the second thread section; and a plurality of side wall concave holes communicated with the pore passages are formed in the side wall of the screw rod between adjacent threads of the second thread section and are used for enabling bone debris to enter the pore passages. According to the spinal column screw, the side wall concave hole is formed, so that when the screw is screwed into a spinal column, bone chippings can be automatically drawn into the hole channel, the bone chippings and bones loaded in the hole channel form protein contact, bone growth is further promoted, and the problem that the screw is loosened for a patient after a spinal column operation is solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of medical devices, in particular, to a pedicle screw. BACKGROUND

[0002] Osteoporosis is a disease characterized by low bone density and degradation of bone microstructure, leading to bone fragility and easy fracture; it is a common disease in the elderly. The screw in spinal surgery, also known as a spinal screw or a pedicle screw, is an important internal fixation device for spinal stabilization and correction surgery. However, the loosening rate of the screw after spinal surgery in osteoporosis patients is as high as 60%, and the loosening rate of the screw after spinal surgery in non-osteoporosis patients is about 1-10%.

[0003] Currently, researchers have made improvements to the screw itself, (1) increasing the diameter of the screw, changing the thread pitch, or expanding the screw, but this improvement is limited by the anatomical structure of the vertebral bone; (2) optimizing the screw insertion route to pass through the area with higher bone density as much as possible, but when applied to osteoporosis patients, its effectiveness cannot be determined; (3) strengthening the screw channel and bone cement injection technology, but it is easy to cause bone cement embolism-pulmonary embolism after treatment.

[0004] Therefore, the problem of screw loosening after existing spinal surgery still needs further research. SUMMARY

[0005] The purpose of the present disclosure is to provide a pedicle screw that can effectively solve the problem of screw loosening faced by patients after spinal surgery.

[0006] To achieve the above purpose, the present disclosure provides a pedicle screw, comprising a screw rod and a spherical head connected to the rear end of the screw rod, the inside of the screw rod is hollow and forms a channel coaxial with the screw rod;

[0007] The first thread segment and the second thread segment are sequentially arranged on the outside of the screw rod in the direction from the rear end to the front end of the screw rod; the thread pitch of the first thread segment is smaller than the thread pitch of the second thread segment;

[0008] A plurality of side wall recessed holes in communication with the channel are arranged on the side wall of the screw rod between adjacent threads of the second thread segment, for allowing bone debris to enter the channel.

[0009] Optionally, the threads of the first thread segment and the second thread segment are independently rotated clockwise in the direction from the front end to the rear end of the screw rod.

[0010] Optionally, each of the side wall concave holes comprises a first side wall and a second side wall in sequence along a direction from a front end to a rear end of the screw rod and along a direction of thread rotation of the second thread section; and an included angle between a vertical line from any point on a side edge of the second side wall away from the screw rod axis to the screw rod axis is 5-30°.

[0011] Optionally, a vertical distance from any point on a side edge of the first side wall away from the screw rod axis to the screw rod axis is R1, a vertical distance from any point on a side edge of the second side wall away from the screw rod axis to the screw rod axis is R2, and a difference between R2 and R1 is 0.05-1.0 mm.

[0012] Optionally, the plurality of side wall concave holes is 3-8.

[0013] Optionally, a first side wall concave hole, a second side wall concave hole, a third side wall concave hole, a fourth side wall concave hole, a fifth side wall concave hole and a sixth side wall concave hole are sequentially arranged on the side wall of the screw rod between adjacent threads in a direction from a front end to a rear end of the screw rod and along a direction of thread rotation of the second thread section.

[0014] Optionally, the first side wall concave hole and the sixth side wall concave hole are arranged towards the same side.

[0015] The second side wall concave hole and the fifth side wall concave hole are arranged towards the same side, and are arranged oppositely to the first side wall concave hole and the sixth side wall concave hole.

[0016] The third side wall concave hole and the fourth side wall concave hole are arranged oppositely, and are arranged oppositely to the first side wall concave hole, the second side wall concave hole, the fifth side wall concave hole and the sixth side wall concave hole.

[0017] Optionally, a length of the second thread section is 1 / 3-3 / 4 of a length of the screw rod.

[0018] Through the above technical solution, the screw can automatically roll the bone debris into the hole when screwing into the spine, and the bone debris is in contact with the bone morphogenetic protein loaded in the hole. The bone morphogenetic protein can promote the bone to grow into the screw on one hand, and can improve the bone density of the vertebral body on the other hand, thereby increasing the stability between the screw and the vertebral body. Thus, the problem of screw loosening faced by patients after spinal surgery is effectively solved.

[0019] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and serve to explain the principles of the present disclosure, but are not intended to limit the present disclosure. In the drawings:

[0021] Figure 1 is a structural schematic diagram of a screw of the present disclosure.

[0022] Figure 2 is a structural schematic diagram of one side of a second thread segment of a screw of the present disclosure.

[0023] Figure 3 is a sectional view of a side wall concave hole of a screw of the present disclosure.

[0024] Legend of reference signs

[0025] 1 screw rod; 2 first thread segment; 3 second thread segment; 4 side wall concave hole; 5 second side wall;

[0026] 6 first side wall; 7 channel. DETAILED DESCRIPTION

[0027] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0028] In the present disclosure, the orientation words such as "inner" and "outer" used without the opposite description refer to the contour of the screw of the present disclosure itself; the terms "first", "second", "third", "fourth", "fifth", "sixth" and the like used in the present disclosure are used to distinguish one element from another element, and do not have sequentiality and importance.

[0029] In the present disclosure, the "front end of the screw rod" refers to the tip portion of the screw; the "rear end of the screw rod" refers to the end connected with the spherical head portion of the screw rod. The "direction of thread rotation of the second thread segment" refers to the direction in which the thread of the second thread segment spirals upward along the screw rod from the front end to the rear end of the screw rod. In the present disclosure, the thread of the second thread segment rotates clockwise in the direction from the front end to the rear end of the screw rod.

[0030] As shown in Figures 1-3 , the present disclosure provides a pedicle screw, which comprises a screw rod 1 and a spherical head portion connected with the rear end of the screw rod 1, the inside of the screw rod 1 is hollow and forms a channel 7 coaxial with the screw rod 1;

[0031] The first thread segment 2 and the second thread segment 3 are sequentially arranged on the outside of the screw rod 1 in the direction from the rear end to the front end of the screw rod 1; the thread pitch of the first thread segment 2 is smaller than the thread pitch of the second thread segment 3;

[0032] Multiple concave holes 4 communicating with the channel 7 are provided on the side wall of the screw between adjacent threads of the second thread segment 3, for allowing bone fragments to enter the channel 7.

[0033] This disclosure, by providing a concave hole on the side wall, enables the screw to automatically draw bone debris into the channel when it is screwed into the spine, allowing it to come into contact with the bone morphogenetic protein loaded in the channel, further promoting bone growth, and thus solving the problem of screw loosening faced by patients after spinal surgery.

[0034] In this disclosure, the aperture of the channel can be the same along the direction from the rear end to the front end of the screw, that is, the shape of the channel is cylindrical; the aperture of the channel can be different along the direction from the rear end to the front end of the screw, for example, the shape of the channel can be conical or frustum-shaped. Bone morphogenetic protein, such as rhBMP-2, can be loaded in the channel.

[0035] According to this disclosure, the threads of the first threaded segment 2 and the second threaded segment 3 each rotate independently clockwise along the direction from the front end to the rear end of the screw 1.

[0036] Furthermore, such as Figure 3 As shown, along the direction of rotation from the front end to the rear end of the screw 1 and along the thread of the second threaded segment 3, each of the sidewall concave holes 4 sequentially includes a first sidewall 6 and a second sidewall 5; the angle between the perpendicular line from any point on the side of the second sidewall 5 away from the screw axis to the screw axis and the second sidewall 5 is 5-30°, preferably 10°.

[0037] In this disclosure, the second sidewall is designed to automatically scrape bone debris into the channel during screw insertion into the bone, facilitating contact with bone morphogenetic proteins within the channel and thereby promoting bone growth, effectively addressing the problem of screw loosening faced by patients after spinal surgery. The design of the first sidewall is not specifically limited.

[0038] Furthermore, such as Figure 3 As shown, the vertical distance from any point on the side of the first sidewall 6 away from the screw axis to the screw axis is R1, and the vertical distance from any point on the side of the second sidewall 5 away from the screw axis to the screw axis is R2. The difference between R2 and R1 is 0.05-1.0mm, preferably 0.1mm.

[0039] In this disclosure, the difference between R2 and R1 is the value of "R2 minus R1". By limiting the difference between R2 and R1, it is easier to scrape bone debris into the channel when the screw is screwed into the bone.

[0040] According to the present disclosure, the plurality of side wall concave holes 4 can be 3-8. For example, the plurality of side wall concave holes can be 6.

[0041] Further, when the side wall concave holes are 6, as shown in Figure 2 and Figure 3 , along the direction of the thread rotation of the front end to the rear end of the screw rod 1 and along the second thread segment 3, the first side wall concave hole, the second side wall concave hole, the third side wall concave hole, the fourth side wall concave hole, the fifth side wall concave hole and the sixth side wall concave hole are sequentially arranged on the side wall of the screw rod between adjacent threads.

[0042] Further, the first side wall concave hole and the sixth side wall concave hole are arranged towards the same side; the second side wall concave hole and the fifth side wall concave hole are arranged towards the same side and opposite to the first side wall concave hole and the sixth side wall concave hole; the third side wall concave hole and the fourth side wall concave hole are arranged opposite to each other and different from the first side wall concave hole, the second side wall concave hole, the fifth side wall concave hole and the sixth side wall concave hole. In the present disclosure, concave holes are arranged in four directions, which can make bone grow into the screw in four directions, provide screw stability in four directions, better stabilize the front end of the screw and the part of the second thread segment, and effectively avoid the phenomenon of "cutting" the vertebral body by the screw.

[0043] According to the present disclosure, the length of the second thread segment 3 is 1 / 3-3 / 4 of the length of the screw rod 1; the total length of the screw can be set according to the spinal structure of the patient, for example, it can be 35mm, 40mm, 45mm and 50mm.

[0044] According to the present disclosure, the thread spacing of the first thread segment can be 2mm; the thread spacing of the second thread segment can be 4mm.

[0045] In the present disclosure, the material of the screw can be titanium alloy.

[0046] In the present disclosure, bone morphogenetic protein is added to the hole 7. The bone morphogenetic protein in the hole helps to promote bone growth into the screw, can increase the bone density of the vertebral body, thereby increasing the stability between the screw and the vertebral body; and further effectively solves the problem of screw loosening faced by patients after spinal surgery.

[0047] In one specific embodiment of the present disclosure, as shown in Figures 1-3As shown, a pedicle screw is made of titanium alloy, and the total length of the screw is 35 mm; the screw comprises a screw rod and a spherical head connected to the rear end of the screw rod, the inside of the screw rod is hollow and forms a hole coaxial with the screw rod; the outside of the screw rod comprises a first threaded segment and a second threaded segment in sequence in the direction from the rear end to the front end of the screw rod, the length of the second threaded segment is 12.5 mm; the thread pitch (2 mm) of the first threaded segment is smaller than the thread pitch (4 mm) of the second threaded segment; a plurality of side wall concave holes communicating with the hole are arranged on the side wall of the screw rod between adjacent threads of the second threaded segment, for allowing bone debris to enter the hole. In the direction from the front end to the rear end of the screw and in the direction of thread rotation of the second threaded segment, each side wall concave hole comprises a first side wall and a second side wall in sequence; the included angle between the perpendicular line from any point on the side edge of the first side wall away from the screw rod axis to the screw rod axis and the first side wall is 10°; the included angle between the perpendicular line from any point on the side edge of the second side wall away from the screw rod axis to the screw rod axis and the second side wall is 10°. The perpendicular distance from any point on the side edge of the first side wall away from the screw rod axis to the screw rod axis is R1, the perpendicular distance from any point on the side edge of the second side wall away from the screw rod axis to the screw rod axis is R2, and the difference between R2 and R1 is 0.1 mm. In the direction from the front end to the rear end of the screw and in the direction of thread rotation of the second threaded segment, a first side wall concave hole, a second side wall concave hole, a third side wall concave hole, a fourth side wall concave hole, a fifth side wall concave hole and a sixth side wall concave hole are arranged in sequence on the side wall of the screw rod between adjacent threads. The first side wall concave hole and the sixth side wall concave hole are arranged towards the same side; the second side wall concave hole and the fifth side wall concave hole are arranged towards the same side, and the direction thereof is opposite to that of the first side wall concave hole and the sixth side wall concave hole; the third side wall concave hole and the fourth side wall concave hole are arranged towards opposite directions, and the direction thereof is different from that of the first side wall concave hole, the second side wall concave hole, the fifth side wall concave hole and the sixth side wall concave hole. Bone morphogenetic protein is added in the hole.

[0048] The preferred embodiments of the present disclosure are described in detail in combination with the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0049] In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0050] In addition, various different embodiments of the present disclosure can also be combined in any appropriate manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A pedicle screw comprising a screw shaft (1) and a spherical head connected to the rear end of the screw shaft (1), characterized in that The screw rod (1) is internally hollow and forms a hole (7) coaxial with the screw rod (1); The screw rod (1) comprises a first threaded section (2) and a second threaded section (3) in sequence from the rear end to the front end of the screw rod (1); the thread pitch of the first threaded section (2) is smaller than that of the second threaded section (3); A plurality of side wall recessed holes (4) are arranged on the side wall of the screw rod between adjacent threads of the second threaded section (3) and communicate with the hole (7), for allowing bone debris to enter the hole (7).

2. The screw of claim 1, wherein The threads of the first threaded section (2) and the second threaded section (3) are independently rotated clockwise along the direction from the front end to the rear end of the screw rod (1).

3. The screw of claim 2, wherein Each of the side wall recessed holes (4) comprises a first side wall (6) and a second side wall (5) in sequence along the direction from the front end to the rear end of the screw rod (1) and along the rotation direction of the threads of the second threaded section (3); The angle between the perpendicular line from any point on the side edge of the second side wall (5) away from the screw rod axis to the screw rod axis and the second side wall (5) is 5-30°.

4. The screw of claim 3, wherein The perpendicular distance from any point on the side edge of the first side wall (6) away from the screw rod axis to the screw rod axis is R1, and the perpendicular distance from any point on the side edge of the second side wall (5) away from the screw rod axis to the screw rod axis is R2, and the difference between R2 and R1 is 0.05-1.0 mm.

5. The screw of claim 4, wherein The plurality of side wall recessed holes (4) are 3-8.

6. The screw of claim 5, wherein, The first side wall recessed hole, the second side wall recessed hole, the third side wall recessed hole, the fourth side wall recessed hole, the fifth side wall recessed hole and the sixth side wall recessed hole are arranged in sequence on the side wall of the screw rod between adjacent threads along the direction from the front end to the rear end of the screw rod (1) and along the rotation direction of the threads of the second threaded section (3).

7. The screw of claim 6, wherein The first side wall recessed hole and the sixth side wall recessed hole are arranged towards the same side; The second side wall recessed hole and the fifth side wall recessed hole are arranged towards the same side, and opposite to the first side wall recessed hole and the sixth side wall recessed hole; The third side wall recessed hole and the fourth side wall recessed hole are arranged opposite to each other, and different from the first side wall recessed hole, the second side wall recessed hole, the fifth side wall recessed hole and the sixth side wall recessed hole.

8. The screw of claim 1, wherein The length of the second threaded section (3) is 1 / 3-3 / 4 of the length of the screw rod (1).

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