WO2016054951A1

WO2016054951A1 - Telescopic double-threaded pull-out resistant pedicle screw assembly for medical use

Info

Publication number: WO2016054951A1
Application number: PCT/CN2015/087622
Authority: WO
Inventors: 王海强; 马驰蛟; 李新奎; 裴延军; 吴智钢; 刘旭; 车路
Original assignee: 中国人民解放军第四军医大学
Priority date: 2014-10-09
Filing date: 2015-08-20
Publication date: 2016-04-14
Also published as: CN104287819B; CN104287819A

Abstract

A telescopic double-threaded pull-out resistant pedicle screw assembly for medical use. A threaded control shaft (3) is provided in a hollow cavity (6) of a screw body (1), the threaded control shaft (3) being matched with connecting rods (4) connected to telescoping screws (8), the telescoping screws (8) being arranged in a plurality of holes opened in the outer wall of and toward the forward extremity of the screw body (1); the cross section of the threaded control shaft (3) is butterfly-shaped and comprises a core shaft (2) and a first support body (9) and a second support body (10) arranged symmetrically opposite one another along the center line of the core shaft (2); two first sliding strips (12) matched with the connecting rods (4) are provided on the outer lateral surfaces of the first support body (9) and of the second support body (10); the cross section of the first sliding strips (12) is crescent-shaped, and the two first sliding strips (12) are oppositely arranged, thus allowing adjustment of the extension and retraction of the telescopic screws (8) while allowing reverse screwing of the thread by rotation of the threaded control shaft (3). Stability of spine internal fixation is improved in cases of osteoporosis or additional placements of pedicle screws, thus reducing the incidence of loosening or even separation of pedicle screws.

Description

Medical retractable double-threaded, pull-out pedicle screw assembly

Technical field

The invention belongs to the field of medical auxiliary devices, and particularly relates to a medical retractable double-threaded, anti-extracting pedicle screw assembly.

Background technique

Spinal fusion is one of the main treatments for many kinds of diseases of the spine. The number of spinal fusion surgery in the United States is increasing year by year. From 1998 to 2008, the number of cervical, thoracic and lumbar fusion cases increased by 90% for every 100,000 people. , 61% and 141% (Rajaee SS, Bae HW, Kanim LE, Delamarter RB. Spinal fusion in the United States: analysis of trends from 1998 to 2008. Spine (Phila Pa 1976) 2012; 37(1): 67-76) . Spinal fusion is often achieved with posterior pedicle screw + fixed rod-nail system, but with the aging of the population and the resulting increase in the incidence of osteoporosis, as well as the spinal column due to loosening of the pedicle screw Increased fusion and need for revision surgery (Rajaee SS, Kanim LEA, Bae HW. National trends in revision spinal fusion in the USA: Patient characteristics and complications. Bone Joint J 2014; 96B (6): 807-16), traditional The pedicle screw fixation technique is extremely challenging. For osteoporosis and vertebral body with secondary nailing during revision, traditional pedicle screw fixation is easy to loose, and it is difficult to achieve firm fixation. In recent years, domestic and foreign scholars have carried out various explorations and improvements, including nail sheathing and expansion. Screw assemblies, injectable screw assemblies, etc., although osteoporosis and revision of the vertebral pedicle screws can be achieved, the changes in the screw assembly after inflation or injection are irreversible. Once the pedicle screw has a problem and the internal fixation needs to be removed, these improvements cannot be achieved smoothly.

Biomechanical studies have shown that the holding force of the pedicle screw and the bone interface, and the area and depth of contact In direct proportion. The deep thread can increase the contact area with the bone and increase the gripping force and pull-out resistance of the screw. Currently used pedicle screws have a thread depth of 1 mm.

Summary of the invention

The object of the present invention is to overcome the disadvantages of the prior art described above, and to provide a medical retractable double-threaded, pull-out pedicle screw assembly, which has a firm fixation and can improve the holding force and the pull-out resistance of the screw. advantage.

In order to achieve the above object, the present invention adopts the following technical solution: a hollow nail body is provided, and a tail end of the nail body is fixed with a nail tail; a hollow threaded control shaft is disposed in the hollow body of the nail body, and the thread control shaft is provided with a rotary groove One end runs through the tail of the nail;

The outer wall of the nail body is fixed with a plurality of fixing threads, and a plurality of holes are formed in the outer wall of the front end of the nail body, and a plurality of retractable screws are arranged in the hole, and a connecting rod is fixed at the bottom of the telescopic screw, and one end of the connecting rod is disposed at Thread control shaft;

The threaded control shaft has a butterfly structure in a cross section, and includes a middle shaft and a first support body and a second support body symmetrically disposed along a center line of the middle shaft; the inner sides of the first support body and the second support body are fixed On the central axis, two outer sides of the first support body and the second support body are fixed with a sliding piece matched with the connecting rod;

The sliding piece has a crescent shape in cross section, and the two sliding pieces are oppositely disposed.

The nail tail is in the shape of a bowl, and an inner thread is arranged on the inner wall thereof.

The lengths of the two oblique sides of the first support body and the second support body are equal, and the angle of the bottom angle is 45°.

The material of the thread control shaft, the connecting rod and the tail is medical titanium alloy.

The diameter of the threaded control shaft is smaller than the diameter of the hollow body.

The height of the fixing thread is 0.8 to 1.2 mm.

The length of the retractable screw is 1.5 to 2.5 mm.

The hollow nail body has an outer diameter of 6 to 7 mm.

The inner hollow body has an inner diameter of 2.5 to 3.5 mm.

The bottom of the connecting rod is fixed with a second sliding piece that cooperates with the first sliding piece.

The present invention has the following beneficial effects: Compared with the prior art, the present invention provides a threaded control shaft in the hollow cavity of the nail body, and the threaded control shaft cooperates with the connecting rod, the connecting rod is connected with the retractable screw, and the retractable screw is set. a plurality of holes are formed in the outer wall of the front end of the nail body, and the cross section of the threaded control shaft has a butterfly structure, and includes a middle shaft and a first support body and a second support body symmetrically disposed along a center line of the middle shaft; The outer side of the support body and the second support body are fixed with two sliding pieces matched with the connecting rod; the cross section of the sliding piece is crescent-shaped, and the two sliding pieces are oppositely arranged; thereby the shaft can be adjusted by rotating the thread, and the adjustment can be The rise and fall of the telescopic screw is extremely convenient to use. The rotation of the thread is controlled by rotating the thread control shaft to improve the stability of the spinal fixation during osteoporosis or revision of the secondary nail, and to reduce the incidence of loosening or even prolapse. In special cases, when the internal fixing needs to be taken out, the retractable screw can be retracted by rotating the thread control shaft to achieve a perfect combination of pull-out and retraction. Reduce the risk of pedicle screw loosening and pulling out. At the same time, the design of the retractable screw also ensures that the pedicle screw can be removed under special circumstances, effectively improving the clinical efficacy.

Further, since the nail tail is in the shape of a bowl, the inner wall is provided with internal threads, thereby reducing the difficulty of the user's operation on the nail body, and making the doctor more convenient to use.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 2 is a schematic view showing the structure of the threaded control shaft in the retracted original state of the present invention.

Figure 3 is a schematic view showing the structure of the threaded control shaft when the present invention is in the extended state.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings.

Referring to Figures 1-3, the present invention includes a hollow nail body 1 having a tail portion 5 fixed to the tail portion of the nail body 1; a hollow threaded control shaft 3 is disposed in the hollow cavity body 6 of the nail body 1, and the thread control shaft 3 is provided. One end of the rotating groove is inserted through the outer end of the nail 5; a fixed thread 7 is fixed on the outer wall of the nail body 1. a plurality of holes are formed in the outer wall of the front end of the nail body 1, and a plurality of retractable screws 8 are provided in the hole, and the retractable screw is provided. The bottom of the 8 is fixed with a connecting rod 4, one end of the connecting rod 4 is disposed in the threaded control shaft 3; the threaded control shaft 3 has a butterfly-shaped cross section, and includes a middle shaft 2 and a line symmetrically disposed along the center line 2 thereof. a support body 9 and a second support body 10; the inner sides of the first support body 9 and the second support body 10 are both fixed to the central shaft 2, and the outer sides of the first support body 9 and the second support body 10 are fixed at two The sliding piece 12 cooperates with the connecting rod 4; the sliding piece 12 has a crescent shape in cross section, and the two sliding pieces 12 are oppositely disposed. The nail tail 5 has a U-shaped cross section and is provided with an internal thread 11 on its inner wall. The lengths of the two oblique sides of the first support body 9 and the second support body 10 are equal, and the angle of the bottom angle is 45°, and the materials of the thread control shaft 3, the connecting rod 4 and the nail tail 5 are all medical titanium alloys. The diameter of the threaded control shaft 3 is smaller than the diameter of the hollow body 6. The height of the fixing thread 7 is 0.8 to 1.2 mm. The retractable screw 8 has a length of 1.5 to 2.5 mm. The outer diameter of the hollow nail body 1 is 6 to 7 mm. The inner diameter of the hollow body 6 is 2.5 to 3.5 mm. The bottom of the connecting rod 4 is fixed with a second sliding piece 13 that cooperates with the first sliding piece 12.

Usage: In the spinal surgery, after the pedicle screw can be accurately established at the pedicle, the pedicle screw assembly can be used to ensure that the double thread height is consistent and the retractable screw 8 is in the original position. After the conventional pedicle screw is implanted, the telescopic pusher is used to control the extension of the retractable screw 8 in the pedicle screw by rotating the screw shaft of the opening of the nail to control the central axis 2 in the shaft 3, thereby realizing the improvement of the screw Bone grip. If the pedicle screw needs to be removed, the snail is realized by rotating the thread to control the central shaft 2 in the shaft 3. The retraction of the retractable screw 8 in the nail enables smooth removal.

When in use:

In the extended state: the central shaft 2 in the shaft 3 is controlled by rotating the screw, and since the inner sides of the first support body 9 and the second support body 10 are fixed to the center shaft 2, the first support body 9 is driven by the rotation of the center shaft 2 and The second support body 10 rotates together, and the two side walls of the first support body 9 and the second support body 10 are pressed and connected with the connecting rod 4 of the retractable screw 8 to raise the retractable screw 8 and extend the thread control shaft 3 After rotating 90°, one end of the connecting rod 4 to which the second sliding piece 13 is fixed is engaged in the two first sliding pieces 12 constituting the butterfly structure, and the butterfly structure positions the retractable screw 8 to avoid sliding thereof. It is fixed and stable; the deep thread can increase the contact area with the bone, and improve the holding force and pull-out force of the screw.

Indented state: rotating the middle shaft 2, the rotation angle is 90°, and the bone is retractable after losing the support of the first support body 9 and the second support body 10 due to the pressure of the bone on the retractable screw 8 The pressure of the screw 8 is retracted into the threaded control shaft 3, thereby greatly reducing the holding force, and at this time, the device can be easily removed from the bone.

Claims

A medical retractable double-threaded, pull-out pedicle screw assembly characterized by comprising a hollow nail body (1), a nail tail (5) fixed to a tail portion of the nail body (1); a nail body (1) a hollow threaded control shaft (3) is disposed in the hollow cavity (6), and one end of the threaded control shaft (3) having the rotary groove is inserted through the tail end (5);

The outer wall of the nail body (1) is fixed with a plurality of fixing threads (7), and a plurality of holes are formed in the outer wall of the front end of the nail body (1), and a plurality of retractable screws (8) and retractable screws are arranged in the holes ( 8) is fixed with a connecting rod (4) at the bottom, and one end of the connecting rod (4) is disposed in the threaded control shaft (3);

The thread control shaft (3) has a butterfly structure in cross section, and includes a central shaft (2) and a first support body (9) and a second support body (10) symmetrically disposed along a center line of the center shaft (2) The inner sides of the first support body (9) and the second support body (10) are both fixed on the central axis (2), and the outer sides of the first support body (9) and the second support body (10) are fixed with two a first sliding piece (12) that cooperates with the connecting rod (4);

The sliding piece (12) has a crescent shape in cross section, and the two first sliding pieces (12) are oppositely disposed.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein said tail (5) is in the shape of a bowl and is provided with internal threads on the inner wall thereof ( 11).
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein said first support body (9) and said second support body (10) are inclined The sides are of equal length and the angle of the base angle is 45°.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1 wherein said threaded control shaft (3), connecting rod (4) and tail (5) The materials are all medical titanium alloys.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1 wherein the diameter of the threaded control shaft (3) is smaller than the diameter of the hollow body (6).
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein said fixing thread (7) has a height of 0.8 to 1.2 mm.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein said retractable screw (8) has a length of 1.5 to 2.5 mm.
The medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein the hollow nail body (1) has an outer diameter of 6 to 7 mm.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein said hollow cavity (6) has an inner diameter of 2.5 to 3.5 mm.
A medical retractable double-threaded, pull-out pedicle screw assembly according to claim 1, wherein the bottom of the connecting rod (4) is fixed with the first sliding piece (12) Cooperating second slider (13).