WO2014015756A1

WO2014015756A1 - Spinal column dynamic connection rod

Info

Publication number: WO2014015756A1
Application number: PCT/CN2013/079524
Authority: WO
Inventors: 冯勇; 黎洁; 吕振杰; 黄加春
Original assignee: 上海微创骨科医疗科技有限公司
Priority date: 2012-07-25
Filing date: 2013-07-17
Publication date: 2014-01-30
Also published as: CN103565502B; CN103565502A

Abstract

A spinal column dynamic connection rod (1) has an upper connection portion (2), a first elastic element (4) and a lower connection portion (3) in longitudinal direction. The upper connection portion (2) and lower connection portion (3) are connected by the first elastic element (4). The first elastic element (4) is provided with an elastic hole (6), and an elastic groove (5) is formed on an outer surrounding of the first elastic element (4) and cuts through or not through the elastic hole (6). The elastic groove (5) could be multi-threaded grooves. The spinal column dynamic connection rod has better mechanical property and fatigue resistance.

Description

Spinal dynamic connecting rod

Technical field

The present invention relates to the field of orthopedic plant technology, and in particular to a spinal dynamic connecting rod. Background technique

When the disc is degenerated or the facet joints are slipped or degenerated, the height of the intervertebral space will be lost, and the posterior structure will be unstable, which will lead to the stenosis of the intervertebral foramen and the vertebral foramen. This stenosis will compress the spinal nerves or nerve roots, causing the patient's waist. Leg pain, numbness and other symptoms, seriously affecting the patient's quality of life

The most important method known to solve this problem is to perform interbody fusion, by which intervertebral height can be maintained and the pressure of the nerve structure can be reduced. At present, the pedicle screw system (the connecting rod in the system is usually a strong metal connecting rod), the cage and various plate-like devices are mainly used for strong fixation. However, the relative fixation of the fusion segments can result in stress concentrations in the adjacent vertebral bodies, especially the load on adjacent vertebral bodies. At the same time, the loss of activity of the fusion segment will lead 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, and changes in the biomechanical environment will eventually lead to proximity. The segment is degenerated. Spinal surgeons and researchers have found that existing pedicle screw systems do not move after implantation. Although it increases the stability of the lumbar spine, it also changes the biomechanical environment of the lumbar spine, leading to the possibility of degeneration of adjacent segments. There are already some lumbar dynamic implants, but their treatment is poor, mainly due to insufficient stability, excessive range of motion, and complications such as spinous process fractures and loose implants, leading to reoperation. The possibility. 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. Recently, several vertebral dynamic connecting rods have been clinically used for the surgical treatment of various degrees of lumbar degenerative symptoms. The main function of these dynamic connecting rods is to provide additional dynamic motion performance while ensuring the stability of the spine. The prior art patent document US20070233075 discloses a pedicle screw system which consists of a screw, a core, an interposer, etc., the core penetrates into the interposer and is placed on the screw of the adjacent vertebral body, and is locked by a special lock. tight. Stabilization and dynamic performance can be provided to the patient by adjusting the stiffness of the core and the interstitial. This prior art pedicle screw system needs to provide a core and an interposer, and thus has a complicated structure and is inconvenient for surgical implantation.

Scient' x-Alphatec Spine has proposed an Isobar® TTL implant, which is a dynamic connecting rod consisting of a complete buffer in the middle of the rod, which consists of a stacked disc Titanium alloy structure that allows for linear expansion and control of axial and angular motion. Each coil spring is nitrogen oxidized to enhance wear resistance. The cushioning characteristics of the connecting rod are designed to allow a maximum axial compression and tension of 0.4 mm while allowing a maximum of ± 2.25° of motion during flexion and extension. The buffering feature acts as a linear elastic "buffer". In a modular assembly system, it is applied to non-fused sections, limiting only flexion and extension and axial movement, but without side bending and torsional properties. In addition, the system includes a pre-convex preset with a proximity of 15 °. The structure of the prior art implant is also complicated, requiring more assembly steps and inconvenient for surgical implantation. The prior art patent document CN100409820C proposes a bio-flexible spinal fixation device with a shape memory alloy, which uses a joint-like flexible longitudinal rod to connect the pedicle screws, and a transverse link to separate the longitudinal rods. It is made of a shape memory alloy, so that the longitudinal rod and the pedicle screw can be easily and conveniently connected. Although the fixing device can obtain good flexibility, the fixing device has weak rigidity and is not stable, and cannot provide sufficient dynamic stability of the spine. The prior art patent document CN102106750A proposes a spinal dynamic connecting rod. The upper connecting portion and the lower connecting portion are connected to each other by the elastic member, wherein the upper connecting portion, the lower connecting portion and the elastic member are integrated Formed in the elastic member, an elastic hole is formed in the elastic member, and an elastic groove is formed in the outer peripheral portion of the elastic member. The spinal dynamic linker maintains spinal stability while maintaining normal physiological activity of the spine. However, this prior art patent document does not provide further suggestions for improving the mechanical properties and fatigue properties of the spinal dynamic connecting rod. Summary of the invention

In view of the deficiencies of the prior art, it is an object of the present invention to develop a spinal dynamic connecting rod which has better mechanical properties and fatigue properties. According to the present invention, there is provided a spinal dynamic connecting rod, the spinal dynamic connecting rod comprising, in a longitudinal direction thereof, an upper connecting end, a first elastic member, and a lower connecting end, the upper connecting end and the lower connecting end An elastic hole is formed in the first elastic member by the first elastic members, and an elastic groove is formed in an outer peripheral portion of the first elastic member and elastic with the first elastic member The holes are connected or not, and the elastic groove is a multi-head spiral groove structure. According to the above aspect of the present invention, the elastic groove of the spinal dynamic connecting rod is a multi-head helical groove structure, whereby the load transmission of the spinal dynamic connecting rod can be more evenly hooked by the action of the multi-head helical groove structure, thereby Make it have better mechanical properties and fatigue

Preferably, the multi-head helical groove structure has a fixed pitch or a varying pitch. Thereby, the linear or non-linear response of the elastic segment structure of the spinal dynamic connecting rod to the load can be controlled. Preferably, the starting point and/or the end position of the elastic groove are set according to the bearing load condition of the spinal dynamic connecting rod, so as to reduce the stress concentration phenomenon generated in the spinal dynamic connecting rod. Thereby, different loads of the rod can be dynamically connected according to the spine To design the starting point and/or the end position of the corresponding elastic groove, the stress concentration of the spinal dynamic connecting rod can be significantly reduced. Preferably, the upper connecting end and the lower connecting end are eccentrically arranged with respect to a center line of the first elastic member, and a cross section of the upper connecting end and/or the lower connecting end is directional Shaped to fit the groove of the corresponding pedicle screw. Here, the "directional shape" means a non-circular cross-sectional shape so that the cross-sectional shape of the upper connecting end and/or the lower connecting end and the corresponding groove of the pedicle screw can be formed. Shape fit connection. The directional shape may be a regular pattern including an ellipse, a diamond, and a polygon, or an irregular pattern. Thereby, the non-circular cross section of the upper connecting end and/or the lower connecting end can be matched with the non-circular pedicle screw groove, so that not only better mounting guiding performance but also more can be realized. For a stable holding force, the spinal dynamic connecting rod is not easily rotated during use. Preferably, the upper connecting end and/or the lower connecting end of the spinal dynamic connecting rod are integrally formed with an extended section, so that the spinal dynamic connecting rod can be used in multi-segment lumbar surgery. The extension may be a rigid straight rod or the extension may have one or more second elastic members. The structure of the second elastic member may be the same as or different from the structure of the first elastic member. The length of the extension may be the length of one or more lumbar segments. Thus, in the case where the extended section is a rigid straight rod, the spinal dynamic connecting rod as a whole can achieve fusion and dynamic stabilization function, and can prevent fusion of adjacent segment degenerative lesions. In the case that the extension is an elastic segment structure, the multi-segment dynamic stabilization function can be realized as a whole on the spinal dynamic connection rod. In summary, the spinal dynamic connecting rod according to the present invention can have better mechanical properties and fatigue properties, thereby ensuring the safety and reliability of the device after implantation in the human body. Moreover, the spinal dynamic connecting rod of the present invention has better elastic performance than other dynamic pedicle screw connecting rods, and meets the biomechanical requirements of the spine; the spinal dynamic connecting rod of the present invention can ensure the stability of the spine, Providing more range of motion of the spine; the spinal dynamic connecting rod of the present invention can also provide a more accurate locking direction of the spinal dynamic connecting rod and More reliable locking; the multi-head helical groove structure in the spinal dynamic connecting rod of the present invention can make the load transmission of the spinal dynamic connecting rod more balanced; the special spiral groove starting point in the spinal dynamic connecting rod of the present invention / or the end point angle design can effectively reduce the stress concentration phenomenon. Multi-head helical grooves and special starting points and/or end points can significantly improve the fatigue performance of the spinal dynamic link system. Moreover, the structure of the present invention mainly relies on a hollow spiral groove to provide elastic properties with variable elastic parameters, so that the entire structure is a single structure, without excessive assembly steps, avoiding wear or failure of the mechanical connection, and is very convenient for surgery. Implanted. DRAWINGS

The above features and advantages of the present invention are readily understood from the following description of the preferred embodiments illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a spinal dynamic link of the present invention applied to the spine.

2 is a perspective view of a spinal dynamic connecting rod in accordance with an embodiment of the present invention. Figure 3 is a perspective schematic view of a spinal dynamic connecting rod in accordance with another embodiment of the present invention.

Figure 4 is a top plan view of the spinal dynamic link showing four different joint configurations.

Figure 5 is a perspective schematic view of a spinal dynamic connecting rod in accordance with still another embodiment of the present invention, wherein the spinal dynamic connecting rod has a double-ended helical groove.

Figure 6 is a top plan view of a spinal dynamic connecting rod showing an example of the design of the starting and ending positions of the helical groove in accordance with one embodiment of the present invention.

Figure 7 is a perspective view of the spinal dynamic connecting rod of Figure 6.

Figure 8 is a perspective schematic view of a spinal dynamic connecting rod having a rigid straight rod as an extension in accordance with still another embodiment of the present invention.

Figure 9 is a perspective view of a spinal dynamic connecting rod in accordance with another embodiment of the present invention, wherein the elongated section has another resilient member. detailed description Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the prior art, the pedicle screw system connecting rod of spinal fusion surgery is usually a solid metal connecting rod. Such a strong metal connecting rod has no elasticity. The sturdy metal connecting rod enables the fusion segments of the spine to be fixed relative to one another. However, the relative fixation of the fusion segment will cause the stress to concentrate toward the adjacent vertebral body; at the same time, the loss of activity of the fusion segment will lead to an increase in the range of motion of the adjacent segment to compensate for the activity of the fusion segment, thereby causing The biomechanical environment of adjacent segments is abnormal; and changes in the biomechanical environment will eventually lead to degeneration of adjacent segments. The device of the present invention belongs to the pedicle dynamic system of spinal non-fusion surgery. 1 is a schematic view of a spinal dynamic connecting rod of the present invention applied to a spine, and FIG. 2 is a perspective view of a spinal dynamic connecting rod according to an embodiment of the present invention. In Figs. 1 and 2, reference numeral 1 denotes a spinal dynamic connecting rod; reference numeral 2 denotes an upper connecting end; reference numeral 3 denotes a lower connecting end; reference numeral 4 denotes an elastic member; and reference numeral 5 denotes an elastic member; Groove; reference numeral 6 denotes an elastic hole. The spinal dynamic connecting rod of the present invention adds a length of elastic member 4 to the original connecting rod, and the elastic member 4 can provide elastic properties for the connecting rod, and maintain a certain range of motion of the spine after the connecting rod is implanted. The entire spinal dynamic connecting rod 1 includes an upper connecting end 2, a lower connecting end 3, an elastic member 4, an elastic groove 5, and an elastic hole 6. After the spinal dynamic connecting rod 1 is implanted into the human body, the elastic member 4 can maintain the movement of the human spine within a certain range of motion. Specifically, the spinal dynamic connecting rod 1 includes, in its longitudinal direction, an upper connecting end 2, an elastic member 4, and a lower connecting end 3. The upper connecting end 2 and the lower connecting end 3 are connected to each other by the elastic member 4. An elastic hole 6 is provided in the elastic member 4, and an elastic groove 5 is formed in the outer peripheral portion of the elastic member 4. The spinal dynamic connecting rod 1 has a monomer structure. The upper connecting end 2 of the spinal dynamic connecting rod 1 is for connection to a part of the human spine structure, and the lower connecting end 3 of the spinal dynamic connecting rod 1 is for connecting to another part of the human spine structure. Upper connection 2 The lower connecting end 3 is connected together by the elastic member 4 located therebetween, and the upper connecting end 2, the lower connecting end 3 and the elastic member 4 are formed in a unitary structure. The upper connecting end 2, the lower connecting end 3, and the elastic member 4 all have a columnar structure. The elastic hole 6 is drilled at a substantially central portion of the elastic member 4, and the elastic hole 6 extends substantially along its center line and penetrates through the elastic member 4 in the longitudinal direction. An elastic groove 5 is cut out in the outer peripheral portion of the elastic member 4. The elastic groove 5 extends spirally in the outer peripheral portion of the elastic member 4. The elastic groove 5 can be formed by hollowing out the outer peripheral portion of the elastic member 4. Since the elastic groove 5 is formed by hollowing out the outer peripheral portion of the elastic member 4, the elastic groove 5 penetrates the outer peripheral portion of the elastic member 4, so that the central elastic hole 6 can communicate with the outside through the elastic groove 5. Further, the elastic groove 5 may be provided in the outer peripheral portion of the elastic member 4 so as not to penetrate the outer peripheral portion of the elastic member 4, at this time, the elastic groove 5 and the elastic hole 6 pass through the outer peripheral portion of the elastic member 4 to each other. The separation is such that the elastic groove 5 does not communicate with the elastic hole 6. Through the spine dynamic connecting rod 1 designed above, the elastic member 4 can maintain the stability of the spine and allow the spine to move within a certain range, thereby maintaining the biomechanical environment of the normal spine. It can be seen from the above that the present invention belongs to a pedicle dynamic system, and the main implementation manner thereof is: After the spinal dynamic connecting rod and the pedicle screw are fixed, the rigidity of the spinal connecting rod is used to provide the immediate stability of the spine, and at the same time, the spine The elastic portion of the dynamic connecting rod can in turn provide mobility of the spine within a certain range, thereby maintaining the biomechanical environment of the normal spine, preventing excessive load caused by strong fixation of adjacent segments, thereby preventing degeneration of adjacent segments. Therefore, the spinal dynamic connecting rod of the present invention can maintain the normal rotation center of the spine while restoring intervertebral height, reducing spinal nerve pressure, and providing spinal stability, providing post-treatment micro-motion and reducing the possibility of degeneration of adjacent segments. . 3 is a perspective view of a spinal dynamic connecting rod according to another embodiment of the present invention, and FIG. 4 is a top view of the spinal dynamic connecting rod showing four different connecting end structures. Similarly, reference numeral 2 denotes an upper connecting end; reference numeral 3 denotes a lower connecting end; reference numeral 4 denotes an elastic member; and reference numeral 6 denotes an elastic hole. As shown in Figures 3 and 4, the upper connecting end 2 and the lower connecting end 3 of the spinal dynamic connecting rod are arranged eccentrically with respect to the center line of the elastic member 4, and the upper connecting end 2 and/or the lower connecting end The cross section of 3 may be directional to fit the recess of the corresponding pedicle screw. The directional shape can be It is a regular figure that includes ovals, diamonds, and polygons, or irregular shapes. The cross-sections of the upper connecting end 2 and the lower connecting end 3 respectively shown in Fig. 4 may be elliptical, square, rhombic or regular hexagon, respectively. Since the installation of the spinal dynamic connecting rod is directional, the non-circular shape of the upper connecting end and/or the lower connecting end can be realized by the cross-sectional shape of the connecting end having a directional shape (non-circular cross section) as described above. The cross-section cooperates with the non-circular pedicle screw groove, so that not only better guiding orientation can be achieved, but also a more stable holding force can be achieved, so that the spinal dynamic connecting rod is not easy to rotate during use. . Figure 5 is a perspective view of a spinal dynamic connecting rod according to still another embodiment of the present invention, wherein the spinal dynamic connecting rod 1 has a double-ended helical groove. As shown in FIG. 5, the spinal dynamic connecting rod 1 is formed with an elastic groove, and the elastic groove may be a multi-head helical groove structure. The "multi-head helical groove" described herein includes a double-headed or more-headed helical groove, and a spine dynamic connecting rod 1 having a structure of a double-ended helical groove is shown in Fig. 5, wherein reference numeral 7 denotes The first head spiral groove, reference numeral 8 denotes the second head spiral groove. Since the elastic groove of the spinal dynamic connecting rod 1 is a multi-head helical groove structure, the load transmission of the spinal dynamic connecting rod can be more uniform by the action of the multi-head helical groove structure. The multi-start helical groove structure may have a fixed pitch or a varying pitch, whereby the linear or non-linear response of the elastic segment structure of the spinal dynamic link to the load may be controlled accordingly. Figure 6 is a top plan view of a spinal dynamic connecting rod showing an example of the design of the starting and ending positions of the helical groove, and Figure 7 is a perspective view of the spinal dynamic connecting rod of Figure 6 in accordance with one embodiment of the present invention. Similarly, reference numeral 1 denotes a spinal dynamic connecting rod; reference numeral 2 denotes an upper connecting end; reference numeral 3 denotes a lower connecting end; and reference numeral 6 denotes an elastic hole. The starting point and the end position of the elastic groove of the spinal dynamic connecting rod have great influence on the stress distribution of the whole structure of the spinal dynamic connecting rod. According to the present invention, the starting point and/or the end position of the elastic groove can be set in accordance with the load-bearing condition of the spinal dynamic connecting rod 1 in order to reduce the stress concentration phenomenon generated in the spinal dynamic connecting rod 1. Therefore, the starting point and/or the end position of the corresponding spiral groove can be designed according to different loads of the spinal dynamic connecting rod 1, so that the dynamic connecting rod 1 of the spinal column can be significantly reduced. Force concentration phenomenon. For example, with regard to the specific angling setting of the starting and/or ending position of the spiral groove, the experimental design can be performed by finite element analysis software. For example, for the spinal dynamic connecting rod 1 having a double-ended helical groove, a design range of an angle α and an angle β may be set in advance (the angle α and the angle β are the starting point and the ending position of the two spiral grooves, respectively). The angle between the neutral faces of the elastic members), and then through the finite element analysis software to find a number of design combinations of two angles in this range, and find the optimal solution by iterative calculation, so that the combination at that angle In the case of a fixed load, the stress generated on the dynamic connecting rod of the spine is minimal (especially the stress on the elastic groove of the elastic member is minimal), so that under the guidance of this design parameter, the dynamic connecting rod of the spine can be subjected to the human body. The possibility of yielding or breaking of material during load conditions is minimized. Finally, it is also possible to combine a specific processing technique to determine an angle combination that is more advantageous for actual processing and that conforms to the above design. For example, if the spine dynamic connecting rod 1 has two spiral grooves, one of the two spiral grooves may have an angle of 30° from the neutral plane, and the other groove may be formed with the neutral surface. 25 ° angle. Figure 8 is a perspective view of a spinal dynamic connecting rod having a rigid straight rod 9 as an elongated section 1 1 according to still another embodiment of the present invention; Figure 9 is a perspective view of a spinal dynamic connecting rod according to another embodiment of the present invention. Schematic, wherein the extension 12 has another resilient member 10. Similarly, reference numeral 2 denotes an upper connecting end; reference numeral 3 denotes a lower connecting end; and reference numeral 4 denotes an elastic member. The upper connecting end 2 and/or the lower connecting end 3 of the spinal dynamic connecting rod may be integrally formed with the extending sections 11 , 12 so that the spinal dynamic connecting rod can be used in multi-segment lumbar surgery . As shown in Figure 8, the extension 11 is a rigid straight rod 9. The extension may also have one or more additional resilient members, as shown in Figure 9, the extension 12 may have an additional resilient member 10, the additional resilient member 10 being configured as previously described The elastic members 4 have the same structure. Furthermore, the structure of the one or more additional elastic members of the extension may also be different from the structure of the elastic member 4 described above. The length of the extensions 1 1 , 12 may be the length of one or more lumbar segments. Thus, in the case where the extended section is a rigid straight rod, the spinal dynamic connecting rod as a whole can achieve fusion and dynamic stabilization function, and can prevent fusion of adjacent segment degenerative lesions. In the case where the extension is an elastic segment structure, the spine dynamic connecting rod can be realized as a whole. Multi-segment dynamic stabilization. In summary, the spinal dynamic connecting rod according to the present invention can have better mechanical properties and fatigue properties, thereby ensuring the safety and reliability of the device after implantation in the human body. Moreover, the spinal dynamic connecting rod of the present invention has better elastic performance than other dynamic pedicle screw connecting rods, and meets the biomechanical requirements of the spine; the spinal dynamic connecting rod of the present invention can ensure the stability of the spine, Providing more range of motion of the spine; the spinal dynamic connecting rod of the present invention can also provide more accurate locking direction of the spinal dynamic connecting rod and more reliable locking; the multi-head helical four-slot structure in the spinal dynamic connecting rod of the present invention The design can make the load transfer of the spinal dynamic connecting rod more balanced; the special spiral groove starting point and/or the ending point declination design in the spinal dynamic connecting rod of the invention can effectively reduce the stress concentration phenomenon. Multi-head helical grooves and special starting points and/or end points can significantly improve the fatigue performance of the spinal dynamic link system. Moreover, the structure of the present invention mainly relies on a hollow spiral groove to provide elastic properties with variable elastic parameters, so that the entire structure is a single structure, without excessive assembly steps, avoiding wear or failure of the mechanical connection, and is very convenient for surgery. Implanted. 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

Claim

A spinal dynamic connecting rod, the spinal dynamic connecting rod (1) comprising, in its longitudinal direction, an upper connecting end (2); a first elastic member (4); and a lower connecting end (3), said upper The connecting end (2) and the lower connecting end (3) are connected to each other by the first elastic member (4), and the first elastic member (4) is provided with an elastic hole (6), and

An elastic groove (5) is formed in an outer peripheral portion of the first elastic member (4) and is in communication with or not in communication with the elastic hole (6) of the first elastic member (4),

It is characterized by:

The elastic groove (5) is a multi-headed spiral groove structure.

2. The spinal dynamic connecting rod according to claim 1, wherein: the multi-head helical groove structure has a fixed pitch or a varying pitch.

The spinal dynamic connecting rod according to claim 1, characterized in that the starting point and/or the ending position of the elastic groove (5) are set according to the load-bearing condition of the spinal dynamic connecting rod (1).

The spinal dynamic connecting rod according to any one of claims 1 to 3, characterized in that:

The upper connecting end (2) and the lower connecting end (3) are eccentrically arranged with respect to a center line of the first elastic member (4), and the upper connecting end (2) and/or the lower connection The cross section of the end (3) is a directional shape.

5. The spinal dynamic connecting rod according to claim 4, wherein: the directional shape is a regular pattern including an ellipse, a diamond, and a polygon, or an irregular pattern.

The spinal dynamic connecting rod according to any one of claims 1 to 3, characterized in that: The upper connecting end (2) and/or the lower connecting end (3) of the spinal dynamic connecting rod (1) are integrally formed with an extended section (11, 12).

7. A spinal dynamic connecting rod according to claim 6, wherein: said extension (11) is a rigid straight rod (9).

8. A spinal dynamic connecting rod according to claim 6, wherein: said extension (12) has one or more second elastic members (10).

9. The spinal dynamic connecting rod according to claim 8, wherein: the structure of the second elastic member (10) is the same as or different from the structure of the first elastic member (4).

10. A spinal dynamic connection rod according to claim 6, characterized in that - the length of the extension (11, 12) is the length of one or more lumbar segments.