WO2012088890A1

WO2012088890A1 - Dynamic pedicel screw implant for vertebral arch

Info

Publication number: WO2012088890A1
Application number: PCT/CN2011/078297
Authority: WO
Inventors: 李雷; 田芳; 刘道志; 冯勇
Original assignee: 上海微创骨科医疗科技有限公司
Priority date: 2010-12-31
Filing date: 2011-08-11
Publication date: 2012-07-05
Also published as: CN102133132B; CN102133132A

Abstract

Disclosed is a dynamic pedicel screw implant for the vertebral arch, which comprises a screw base (1), a compression ring (2), a screw (4), a connecting bar (6) and a compression nut (7). The screw (4) includes a screw main body (16) and a connecting head (8), the connecting head (8) being accommodated in the screw base (1). The connecting bar (6) is arranged in an open slot of the screw base (1) and is located between the compression ring (2) and the compression nut (7). The compression nut (7) is used for screwing into the upper part of the screw base (1) so as to press the connecting bar (6) tightly. The dynamic pedicel screw implant for the vertebral arch is also provided with a screw bush (3) which is of a ball seat structure (13) on the inside. The connecting head (8) of the screw (4) has a spherical external structure, so that the ball seat structure (13) can fit the connecting head (8) of the screw (4). The dynamic pedicel screw implant for the vertebral arch of the present invention is able to provide not only the traditional multi-axial swinging, but also additional swinging angles after being locked, and it is able to ensure the stability of the spine.

Description

Dynamic pedicle screw implant

The present invention relates to the field of orthopedic plant technology, and in particular to dynamic pedicle screw implants. Background technique

When the disc is degenerated or the facet joints are slipped or degenerated, the height of the intervertebral space is lost, and the posterior structure is unstable, resulting in stenosis of the intervertebral foramen and vertebral foramen, which will compress the spinal nerves or nerve roots, causing pain in the patient's back and legs. Symptoms such as numbness seriously affect the quality of life of patients. A known method to solve this problem is conservative treatment of medicine, which is intended to control the condition, ie pain, numbness, rather than correction to solve the problem. For some patients, this may require long-term treatment, which may require long-term use of painkillers, which may cause the patient's mental state or other adverse side effects. Another known method is intervertebral fusion or interspinous fusion, which maintains the intervertebral height and reduces the pressure on the nerve structure. It can be fixed with a cage, various plate devices and a pedicle screw system. However, the fusion causes the upper and lower vertebral bodies to grow into a single unit, causing the patient to lose mobility because it prevents movement of the spine in any direction of the problem segment. What's more serious is that it brings new problems, the degeneration of adjacent spine segments. It is known that the relative fixation of the spinal fusion segments results in the concentration of stresses in the adjacent vertebral bodies, in particular the loading of adjacent vertebral bodies. At the same time, the loss of activity of the fusion segment leads to an increase in the range of motion of adjacent segments to compensate for the activity of the fusion segment, thereby causing abnormalities in the biomechanical environment of adjacent segments. The change in the biomechanical environment ultimately leads to the adjacent segment. The segment is degenerated. Therefore, spine surgeons and researchers have found that existing pedicle screws do not move after implantation, although the stability of the lumbar spine is increased, but the biomechanical environment of the lumbar spine is changed, resulting in degeneration of adjacent segments. possibility. Although some lumbar dynamic implants have emerged, their therapeutic effects are poor, and there are complications such as spinous process fractures and loose implants, which may lead to reoperation. On the other hand, these implants are not or unsuitable for the treatment of more severe lumbar degenerative symptoms, resulting in a narrow range of applications for these implants. Patent document CN200680020249 discloses an interspinous spine and lumbosacral stabilization device and method of use, in particular, it discloses a U-shaped spinous process flexible spacer, and a pair of lateral walls configured to engage the spinous processes of the vertebra; A fixation sleeve can be provided to secure the spinous processes of the vertebrae to the flexible spacer; an anchoring assembly is provided for securing the flexible spacer between the lumbar vertebrae and the adjacent vertebra; and the implantable device is used to stabilize the patient's spine Methods. The patent document US 20100100137 discloses an implant comprising a multi-axial anchor and a connector; the anchor has a flexible means capable of providing articulation allowing a certain movement after the multi-axial anchor is fixed. However, this prior art structure is less stable and can only provide limited dynamic activity; in addition, the prior art assembly performance is not very good. Patent document US 20050192571 discloses a pedicle flexible assembly and method comprising a screw head having a male ridge structure; a bone fixation structure having a female hemispherical hemispherical structure forming a ball and socket joint; a locking fixed pin fixing screw Head and bone fixation structure; a stop for ensuring long axial stability. Patent document CN200480038132 discloses a bone anchoring element and a stabilization device for bone or vertebra comprising a bone anchoring element of this type, wherein the bone anchoring element comprises a shank for anchoring in the bone, The rod has a first portion that is anchorable in the bone and a second portion that is resiliently formed; and includes a nail head configured to connect a rod that connects at least two bone anchoring elements . The prior art is mainly in common pedicle A counterbore is made at the tip end until the neck of the screw, and a spiral groove is cut in the wall of the hole. This will significantly reduce the strength of the neck of the screw, so the actual feasibility may not be high. Summary of the invention

In view of the deficiencies of the prior art, it is an object of the present invention to develop a dynamic pedicle screw implant that allows the screw to provide both a conventional multi-axial pivot angle and Provides additional angular oscillations after locking and ensures stability of the spine. According to a first aspect of the present invention, a dynamic pedicle screw implant is provided, comprising: a screw seat; a pressure ring; a screw; a connecting rod; and a compression nut,

Wherein the screw includes a screw body and a connector, the connector is received in the screw seat; the connecting rod is disposed in a slot of the screw seat, and is located at the pressure ring and the compression nut Between; the compression nut is used to screw into the upper portion of the screw seat, thereby pressing the connecting rod,

It is characterized by:

The dynamic pedicle screw implant is further provided with a screw head cover, the inside of the screw head cover is a ball and socket structure, and the connector of the screw has a spherical outer structure, so that the ball and socket structure can be connected with the screw Match. According to the above structure, a screw head cover is provided, and the main function of the screw head cover is to wrap the connector of the screw, so that the screw head of the universal joint can perform multi-axial micro-angle swing in the screw head cover even after being fixed. . Thus, the screw has a conventional multi-axial pivot angle, provides additional angular oscillation after locking, and ensures the stability of the spine. The additional angular oscillation prevents excessive loading of adjacent segments due to strong fixation, thereby preventing degeneration of adjacent segments. Preferably, the lower portion of the screw head cover has a lip structure that cooperates with the neck of the screw and is arranged such that the inner side of the lip structure can limit the secondary swing angle of the screw, and the outer side of the lip structure The main swing angle of the screw can be controlled. According to the above configuration, the lip portion of the screw head cover and the neck of the screw are designed to limit the range of the swing angle of the screw. Therefore, the structure of the present invention can increase the small angle swing of the screw, can improve the stress distribution of the adjacent segments, reduce the possibility of degeneration of the adjacent segments, and maintain the physiological activity range of the spine, thereby realizing dynamic fixation. Preferably, the inner portion of the pressure ring has a concave surface, and the concave surface is spherical to cooperate with the spherical outer wall of the screw head cover. According to the above structure, the inner spherical surface of the pressure ring is matched with the outer spherical surface of the screw head cover, so that the screw head cover encloses the screw and is inserted into the screw seat, and has a multi-axial large-angle swing, thereby realizing a conventional universal screw to facilitate the doctor. Implantation is performed from various angles. Thus, the present invention provides both a large angle of the screw during implantation and a small displacement swing after implantation. Preferably, the spherical outer wall of the screw head cover has a stepped portion such that the inner concave surface of the pressure ring contacts the stepped portion of the screw head cover. According to the above configuration, the concave surface of the pressure ring is in contact with the step portion of the screw head cover and transmits pressure, so that it is possible to better control the multi-axial large-angle oscillation of the screw. Preferably, the outer circumference of the pressure ring cooperates with the inner cavity of the screw seat, so that the pressure ring can move axially along the screw seat. According to the above structure, the pressure ring can be axially moved along the screw seat, so that the assembly of the dynamic pedicle screw implant of the present invention can be better achieved, and screwing from the upper portion by the compression nut, The screw head cover can be fixed in the screw seat to facilitate control of the multi-axis large angle swing of the screw. Preferably, the outer circumference of the screw head cover has a plurality of strip-shaped slots. According to the above structure, the strip groove can provide an expansion space when the connector of the screw is inserted into the screw head cover to facilitate the insertion of the screw. Preferably, the dynamic pedicle screw implant includes a retaining ring for embedding into a recess in a lower portion of the inner cavity of the screw seat while being in contact with the screw head cover. According to the above structure, the screw head cover can be fixed in the screw seat, thereby restricting the displacement of the screw in the axial direction, thereby facilitating the control of the multi-axis large-angle swing of the screw. Preferably, an opening is provided in the retaining ring. According to the above configuration, the retaining ring is provided with an opening, so that the insertion and assembly of the retaining ring can be facilitated. In summary, according to the technical solution of the present invention, the gimbal screw can be provided with dynamic fixed performance; and, the screw can be adapted to adapt the bending center of the spine after implantation; and the adjacent segments of the spine can be prevented from degenerating. Thus, while maintaining the intervertebral height, reducing spinal nerve pressure, and providing spinal stability, the normal center of rotation of the spine is maintained, providing post-treatment micro-motion, reducing the likelihood of degeneration of adjacent segments of the spine. The above features and advantages of the present invention will be readily understood from the preferred embodiments described in the appended claims. DRAWINGS

1 is an overall perspective view of a dynamic pedicle screw implant of the present invention.

2 is an exploded perspective view of the dynamic pedicle screw implant of the present invention.

3 is a cross-sectional view of a dynamic pedicle screw implant of the present invention.

Figure 4 is a schematic view of the screw of the dynamic pedicle screw implant of the present invention, wherein Figure 4 (a) is a perspective view of the screw, and Figure 4 (b) is a cross-sectional view of the screw.

Figure 5 is a perspective view of the retaining ring of the dynamic pedicle screw implant of the present invention.

Figure 6 is a schematic view of the screw head cover of the dynamic pedicle screw implant of the present invention, wherein Figure 6 (a) is a cross-sectional view of the screw head cover, Figure 6 (b) is a perspective view of the screw head cover, Figure 6 (c) It is a front view of the screw head cover, and Figure 6 (d) is a top view of the screw head cover.

Figure 7 is a schematic view of a compression ring of a dynamic pedicle screw implant of the present invention, wherein Figure 7 (a) is a perspective view of the pressure ring, and Figure 7 (b) is a transverse cross-sectional view of the pressure ring.

Figure 8 is a schematic illustration of a screw seat of a dynamic pedicle screw implant of the present invention, wherein Figure 8 (a) is a perspective view of the screw seat and Figure 8 (b) is a cross-sectional view of the screw seat. detailed description

Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. 1 is an overall perspective view of a dynamic pedicle screw implant of the present invention, FIG. 2 is an exploded perspective view of the dynamic pedicle screw implant of the present invention, and FIG. 3 is a dynamic pedicle screw implant of the present invention. A cross-sectional view of the input. Referring to Figures 1-3, a dynamic pedicle screw implant for implantation in a vertebral body of the present invention includes: a screw seat 1; a pressure ring 2; a screw head cover 3; a screw 4; a retaining ring 5; 6; and the compression nut 7. Figure 4 is a schematic illustration of a screw 4 of a dynamic pedicle screw implant of the present invention, wherein Figure 4 (a) is a perspective view of the screw and Figure 4 (b) is a cross-sectional view of the screw. As seen in Figure 4, the screw of the dynamic pedicle screw implant of the present invention includes a screw body 16 and a connector 8. The screw body 16 has a threaded structure for bone fixation, in particular for vertebral fixation. The connector 8 has a generally spherical outer shape and is located at one end of the screw body 16 and is integrally connected to the screw body 16. The connector 8 of the screw 4 can be inserted into the ball and socket structure 13 of the screw head cover 3 to be connected to the screw head cover 3. The top end of the connector 8 is provided with an interface 9 for facilitating the connection of the instruments. Figure 5 is a perspective view of the retaining ring 5 of the dynamic pedicle screw implant of the present invention. Retaining ring 5 It can be inserted into the recess 17 in the lower portion of the screw seat 1 while being in contact with the screw head cover 3, so that it can restrict the screw 4 from coming out while providing the swing angle of the screw 4. Preferably, the retaining ring 5 is provided with an opening 18 to facilitate the inset assembly of the retaining ring 5. Figure 6 is a schematic view of the screw head cover 3 of the dynamic pedicle screw implant of the present invention, wherein Figure 6 (a) is a cross-sectional view of the screw head cover 3, and Figure 6 (b) is a perspective view of the screw head cover 3, Figure 6 (c) is a front view of the screw head cover 3, and Fig. 6 (d) is a top view of the screw head cover 3. Specifically, the screw head cover 3 is a structure of a generally hollow ball as a whole. The screw head cover 3 has an upper through hole 10 at its upper portion and a lower through hole 11 at its lower portion. The upper through hole 10 facilitates screwing of the upper nailing device, and the lower through hole 11 is an insertion hole for inserting the screw 4. The outer periphery of the screw head cover 3 has a plurality of strip-shaped slots 12; preferably, in the present embodiment, the strip heads 3 have three strip-shaped slots 12 on the upper and lower sides of the outer circumference. These strip slots 12 provide an expanded space when the connector 8 of the screw 4 is inserted into the screw head cover 3 to facilitate insertion of the screw 4. As can be seen from Fig. 6, the inside of the screw head cover 3 is a ball and socket structure 13, which is used to engage the joint 8 of the screw 4, thereby forming a ball and socket joint. The spherical outer wall of the screw head cover 3 has a step portion 14 which gradually decreases in diameter in the height direction of the screw head cover 3. The step 14 can cooperate with the inner concave surface 19 of the pressure ring 2 to transmit a compressive load to lock the main swing angle of the screw. The lower portion of the screw head cover 3 has a lip structure 15, the inner side of which can limit the secondary swing angle of the screw, and the outer side of the lip structure 15 can control the main swing angle of the screw. Figure 7 is a schematic view of the pressure ring 2 of the dynamic pedicle screw implant of the present invention, wherein Figure 7 (a) is a perspective view of the pressure ring 2, and Figure 7 (b) is a transverse cross-sectional view of the pressure ring 2. The pressure ring 2 has an upper nail insertion hole 20. The outer circumference of the pressure ring 2 is engaged with the inner cavity of the screw seat 1, so that the pressure ring 2 can move axially along the screw seat 1. The inside of the pressure ring 2 is a spherical inner concave surface 19 which is in contact with the step portion 14 of the screw head cover 3. The pressure ring 2 relies on the connecting rod 6 provided at the upper portion to supply pressure to the screw head cover 1. Figure 8 is a schematic view of a screw seat 1 of a dynamic pedicle screw implant of the present invention, wherein Figure 8 (a) is a perspective view of the screw base 1, and Figure 8 (b) is a cross-sectional view of the screw base 1. The screw seat 1 has an inner cavity 21 comprising a threaded upper portion and a smooth lower portion, the inner chamber 21 accommodating the retaining ring 5, the connector 8 of the screw 4, the screw head cover 3 and the pressure ring 2 And provide a guiding action for the axial movement of the pressure ring 2. The screw seat 1 also has a U-shaped slot 22 for placing the connecting rod 6. The inner side of the upper portion of the screw seat 1 has a threaded structure to facilitate engagement with the compression nut 7. A groove 17 is provided in the lower peripheral wall of the smooth lower portion of the inner cavity 21 of the screw seat 1 in the circumferential direction, and the retaining ring 5 can be inserted into the groove 17 of the screw seat 1 for fixing the retaining ring 17, Thereby limiting the downward displacement of the screw 4. The connecting rod 6 is used for connecting a plurality of screws, and the connecting rod 6 is provided in the U-shaped groove of the screw seat 1.

22, and located between the pressure ring 2 and the compression nut 7. The compression nut 7 can be screwed into the inner side of the upper portion of the screw seat 1 to be connected to the screw seat 1 for pressing the connecting rod 6. As can be seen from the above embodiments, according to the dynamic pedicle screw implant of the present invention, a screw head cover device is further provided on the basis of the conventional pedicle screw and the screw structure is improved. As is known in the prior art, after the conventional pedicle universal joint screw is fixed, the screw head and the screw seat have a certain angle and the screw head can no longer swing any more, which is a strong fixing manner. However, according to the present invention, the dynamic pedicle screw implant is further provided with a screw head cover, the inside of the screw head cover is a ball and socket structure, and the connector of the screw has a spherical outer structure, so that the ball and socket structure can The connectors of the screws cooperate. With the above arrangement, the present invention can prevent the adjacent segments of the spine from degenerating and retain the degree of spinal activity. That is, the present invention provides a screw head cover, the main function of which is to wrap the connector of the screw so that the screw head of the universal joint can perform a multi-axial micro-angle swing in the screw head cover even after being fixed. Moreover, according to the present invention, the lower portion of the screw head cover has a lip structure, and the lip structure Cooperating with the neck of the screw and arranged such that the inside of the lip structure can limit the secondary swing angle of the screw, the outer side of the lip structure being capable of controlling the main swing angle of the screw. With the above arrangement, the lip of the screw head cover and the neck of the screw are designed to limit the range of the angle of swing of the screw. This limited small angle swing is an important aspect of the present invention, which provides the advantages of: increased small angle swing of the screw, improved stress distribution of adjacent segments, reduced likelihood of degeneration of adjacent segments, and maintenance The range of physiological activities of the spine is dynamically fixed, which is more in line with the requirements of clinical application, and the clinical effect is better. Further, according to the present invention, the inside of the pressure ring has an inner concave surface which is spherical to cooperate with the spherical outer wall of the screw head cover. Therefore, the inner spherical surface of the pressure ring cooperates with the outer spherical surface of the screw head cover, so that the screw head cover encloses the screw and fits into the screw seat, and has a multi-axial large-angle swing (this is similar to the function of the conventional universal screw, but realizes The structure is different), so that the traditional universal screw is realized to facilitate the doctor to perform the implantation from various angles. δΡ, the present invention can provide both a large angle of the screw during implantation and a small displacement swing after implantation. During the implantation operation, the doctor can adjust the angle range of the screw head and the nail seat according to actual needs, which facilitates the implantation of the screw. When implanted in the correct position, the compression nut is pressed so that the pressure ring fits tightly with the screw head sleeve, thereby limiting the multi-axial oscillation of the screw head sleeve, that is, locking the angle of insertion of the screw. At this time, the screw located in the screw sleeve can also swing at a slight angle. The size of the swing is only related to the lip design of the screw sleeve, and it does not matter whether the screw is locked or not. In addition, the dynamic pedicle screw implant of the present invention may be made of a metal material such as a titanium alloy, a cobalt-based alloy, or a nickel-titanium alloy; in addition, the partial structure of the implant of the present invention may also be composed of polyetheretherketone, Made of PCU, reinforced polyetheretherketone, ultra-high molecular weight polyethylene and other polymers or composite materials. Various modifications and improvements of the details of the embodiments of the present invention can be readily made by those skilled in the art. These variations and modifications are intended to fall within the scope of the inventive concept.

Claims

A dynamic pedicle screw implant comprising: a screw seat (1); a pressure ring (2); a screw (4); a connecting rod (6); and a compression nut (7),

Wherein the screw (4) comprises a screw body (16) and a connector (8), the connector (8) is received in the screw seat (1); the connecting rod (6) is disposed on the screw In the slot (22) of the seat (1), and between the pressure ring (2) and the compression nut (7); the compression nut (7) is used to screw into the screw seat ( The upper part of 1), thereby pressing the connecting rod (6),

It is characterized by:

The dynamic pedicle screw implant is further provided with a screw head cover (3), the inside of the screw head cover (3) is a ball and socket structure (13), and the connector (8) of the screw (4) has a spherical outer portion The structure, such that the ball and socket structure (13) can cooperate with the connector (8) of the screw (4).

2. The dynamic pedicle screw implant according to claim 1, wherein the lower portion of the screw head cover (3) has a lip structure (15), the lip structure (15) and the neck of the screw The portions cooperate and are arranged such that the inner side of the lip structure (15) can limit the secondary swing angle of the screw, and the outer side of the lip structure (15) can control the main swing angle of the screw.

The dynamic pedicle screw implant according to claim 1 or 2, wherein the inner portion of the pressure ring (2) has a concave surface (19), and the concave surface (19) is spherical. In order to cooperate with the spherical outer wall of the screw head cover (3).

The dynamic pedicle screw implant according to claim 3, wherein the spherical outer wall of the screw head cover (3) has a step portion (14) such that the pressure ring (2) The concave surface (19) is in contact with the stepped portion (14) of the screw head cover (3).

The dynamic pedicle screw implant according to claim 1 or 2, characterized in that the outer circumference of the pressure ring (2) is engaged with the inner cavity of the screw seat (1), so that The pressure ring (2) is axially movable along the screw seat (1).

The dynamic pedicle screw implant according to claim 1 or 2, characterized in that the outer circumference of the screw head cover (3) has a plurality of strip-shaped slots (12).

The dynamic pedicle screw implant according to claim 1 or 2, wherein the dynamic pedicle screw implant comprises a retaining ring (5), and the retaining ring (5) is used for It is embedded in the recess (17) in the lower part of the inner cavity (21) of the screw seat (1) while being in contact with the screw head cover (3).

The dynamic pedicle screw implant according to claim 7, characterized in that the retaining ring (5) is provided with an opening (18).