CN111544103A - Spine fixing system - Google Patents

Abstract

The invention provides a spinal fixation system, belonging to orthopedic implants, comprising a spinal bone plate and screws, wherein the screws are matched with nail holes of the bone plate and used for fixing the bone plate. When the spine fixation system is used, the screw penetrates through the screw hole to fix the bone plate on the bone, and meanwhile, the depth of the thread is increased, the surface structure of the thread is improved, so that the holding force and the anti-pull force of the screw are increased, the long-term stability of the screw is ensured, a good effect is achieved, and the bone healing is facilitated.

Description

a spinal fixation system

technical field

The present invention relates to an orthopaedic implant, in particular, to a fixation system for stabilizing the spine.

Background technique

The human spine will be damaged due to patients or external forces, such as vertebral body tumors, severe comminuted fractures, and infectious diseases such as tuberculosis, which may lead to spinal cord and nerve damage or collapse of vertebral segments and angular deformity of the spine. Causes various injuries to the spine of the human body. Spinal fractures are very common, accounting for about 5%-6% of all body fractures. The main symptoms of spinal fracture or dislocation are local pain, difficulty in standing and turning over, and retroperitoneal hematoma stimulates the celiac ganglia, which slows down bowel motility, often causing abdominal pain, abdominal distension and even intestinal paralysis. Therefore, the effective treatment of spinal fractures is of great significance.

Plates and pins are used in some procedures for spinal fractures or dislocations. The plate is fastened to the bony tissue of the spine with bone fasteners passed through the plate to join two or more vertebral bodies to Fix part of the spine in the desired position. The fixation plate must meet the stability of the spine and the reliability of the system during long-term use, ensure that the bone fasteners will not loosen or withdraw from the plate, and ensure the fixation between the plate and the bone.

In this regard, some spinal bone plates are disclosed in the prior art, such as the anterior cervical spine plate disclosed in Chinese patent document CN203001098U, in which a fixing ring is provided, and the design of expanding and tightening and preventing dislocation while preventing dislocation of the thread is adopted, which is convenient for screws with multiple angles. However, in this technical solution, after the screw is implanted, the anti-drop-off effect is achieved through the anti-drop-off thread, which is difficult to achieve the fretting effect, which is not conducive to postoperative healing. And the plate applied to the spine is different from the plate used for other parts of the human body. The bone plate cannot be too thick, so even if the screw head is completely threaded outside and the screw hole is completely threaded, the combination of the two cannot achieve stable locking. As a result, once the implant is implanted in the human body, it will exist in the human body for a long time. At the same time, with the continuous force of the human action, the screw is prone to loosening. Therefore, effective anti-retraction is also one of the problems to be solved.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is that the spinal bone plate in the prior art has the problems of weak fixation and slow healing, so as to provide a spinal fixation system with firm fixation and favorable healing.

In order to solve the above technical problems, the spinal fixation system of the present invention provides a spinal fixation system, which includes a bone plate and a screw, and the bone plate includes a plate body, a plate hole and a nail hole sleeve inserted into the plate hole; the nail hole sleeve It is made of elastic material, and is provided with an engaging part which is combined with the plate hole to prevent the rotation of the nail hole sleeve; the nail hole sleeve is provided with a hole penetrating the upper surface and the lower surface of the upper plate, For the screws to pass through, the upper surface of the nail hole sleeve is provided with an inwardly extending flange, and the lower part of the flange is provided with a downward protrusion; at least one of the screws is used for inserting the nail hole sleeve, the There are grooves on the upper surface of the screw head, which are matched with the protrusions on the nail hole sleeve; the rod part of the screw has an upper section and a lower section, the upper section has a first type of thread, and the lower section includes a second type of thread The thread, the width of the tooth tip of the first type of thread is greater than that of the second type of thread, and the tail of the upper section has a third type of thread.

The height of the downward protrusion of the nail hole sleeve is smaller than the depth of the groove on the surface of the nail head.

The bottom surface and inner surface of the downward protrusion of the nail hole sleeve are rough surfaces.

The length of the upper section is at least twice the length of the lower section.

The third thread constitutes at least one quarter of the upper section.

The lower section has a hollow structure, and the surface of the hollow structure has internal threads.

An elastic threaded outer sleeve is arranged in the lower hollow structure, and an inner groove is arranged on the inner side of the elastic threaded outer sleeve. The inner diameter of the inner groove of the elastic threaded outer sleeve is larger than the spiral width of the third type of thread. An integrated structure is formed in the inner groove of the elastic threaded outer sleeve, and is matched and locked with the inner thread.

The bottom surface of the bone plate body and the outer surface of the second thread have a grid-like structure.

The grid-like structure is a network-like lattice structure, and the distance between two opposite lattice planes of the lattice structure is 0.01-0.05 mm.

The position of the nail hole of the plate body is a ridge-shaped protrusion.

Compared with the prior art, the above technical solution of the present invention has the following advantages.

1) In the spinal fixation system of the present invention, the upper surface of the nail hole sleeve inserted into the hole of the bone plate is provided with an inwardly extending flange, and a downward protrusion is provided below the flange, and the screw is connected to the nail hole on the plate. The upper surface of the nail head is provided with grooves, which are matched with the protrusions on the nail hole sleeve. Since there is a gap between the screw hole sleeve and the screw head, the screw head is allowed to move slightly to promote fracture healing; at the same time, if the screw head moves slightly in the screw hole sleeve and the screw tends to withdraw, the bulge under the flange will Against the groove on the nail head, it not only provides a force from above to prevent the nail head from withdrawing upwards, but also provides a force from the side to prevent the nail head from moving in the lateral direction, so as to completely prevent the nail head from withdrawing.

Preferably, the bottom surface and the inner surface that protrude downward in the nail hole sleeve are rough surfaces, such as being provided with bumps, corrugations or spikes, to further strengthen the fixation with the nail head.

2) The upper and lower sections of the screw of the present invention are fitted with threads, and an elastic thread jacket is sleeved at the thread at the end of the upper section to be combined with the inner thread of the lower section. This unique combination ensures the overall fretting effect of the screw. The screw connection of the present invention has a circumferential gap, which can guide the screw fracture area under the condition of excessive force.

3) In the spinal fixation system of the present invention, the bottom surface of the bone plate body and the outer surface of the second type of thread have a grid-like structure, which increases the holding force between the bone surface and the bone surface, and has a strong compressive ability to strengthen fixed role.

Description of drawings

1 is an exploded view of a spinal fixation system of the present invention;

Fig. 2 is the side view of the nail hole sleeve and the screw in the spinal fixation system of the present invention;

3 is a side view of another nail hole sleeve of the spinal fixation system of the present invention;

4 is a perspective view of the screw head in the spinal fixation system of the present invention;

5 is a perspective view of a screw shaft in the spinal fixation system of the present invention;

6 is a partial enlarged view of the upper thread structure in the spinal fixation system of the present invention;

7 is an exploded view of the screw shaft in the spinal fixation system of the present invention;

8 is a schematic diagram of the combination of the upper end of the screw and the elastic jacket in the spinal fixation system of the present invention;

9 is a perspective view of a spine fixation system with a lattice structure layer on the bottom surface of the present invention;

FIG. 10 is a partial enlarged view of the lattice structure in FIG. 7 .

reference number

1 - bone plate,

2-screw, 21-groove, upper rod section-22, lower rod section-23, upper tail section-221, slot 222, protrusion 223, spiral slot 224, threaded jacket 24,

3- Bone plate body, 4- Plate hole, 5- Nail hole sleeve, 51- Engagement part, 52- Flange, 53- Protrusion, 6- First end, 7- Second end, 8- Connecting section, 9- ridge, 10- lattice structure layer, 11- tetradecahedral lattice structure.

Detailed ways

The spinal fixation system of the present invention will be further described in detail below through specific embodiments.

As shown in Figures 1 to 4, the spinal fixation system of the present invention is used to stabilize the spine, and is made of titanium alloy or PEEK, including a bone plate 1 and a screw 2, the bone plate 1 includes a plate body 3, a plate hole 4 and The nail hole sleeve 5 inserted into the plate hole; the bone plate has a first end 6 and a second end 7, there is one or more connecting sections 8 between the first end 6 and the second end 7, the first end, the second end and Each connecting segment has a pair of plate holes 4 . There is a nail hole sleeve 5 in the plate hole 4, the nail hole sleeve 5 is made of elastic material, the elastic material is memory alloy or elastic polymer material, and the nail hole sleeve 5 and the plate hole are arranged between them. There are engaging parts 51 which are combined with each other to prevent the rotation of the plate hole sleeve; the nail hole sleeve 5 is provided with holes penetrating the upper surface and the lower surface of the plate for screws to pass through, and the nail hole sleeve is provided on the upper surface An inwardly extending flange 52 is provided, and a downward projection 53 is provided below the flange 52 .

The screw 2 is made of titanium alloy or PEEK material, and is matched with the nail hole sleeve 5 on the board; the upper surface of the nail head of the screw has a groove 21, which is matched with the protrusion on the nail hole sleeve. The grooves 21 on the surface of the head of the screw extend downward from the upper surface, occupying 1/10 to 1/4 of the height of the entire head. The grooves are arranged on the outer circumference of the upper surface of the nail head, in the area of 1/3 to 1/20 of the radius. The height of the downward protrusion of the nail hole sleeve is smaller than the depth of the groove on the surface of the nail head.

In the embodiment shown in FIG. 2 , the grooves 21 on the surface of the screw head extend downward from the upper surface, occupying about 1/10 of the height of the entire nail head; /5 to 1/15; the height of the downward protrusion of the nail hole sleeve is less than the depth of the groove on the surface of the nail head. For the screw matched with the nail hole sleeve shown in FIG. 3, the groove 21 on the surface of the nail head extends downward from the upper surface, accounting for about 1/8 of the height of the entire nail head; 1/10 to 1/4 area.

In other implementations, the bottom surface and inner surface of the nail hole sleeve that protrudes downward can be set as rough surfaces, provided with convex points, and can also be set as corrugations or spikes to increase the friction force with the screw head.

As shown in FIG. 5 , the shank of the screw defines a longitudinal axis Y, and the shank includes an upper section 22 and a lower section 23 , the upper section 22 has a tail 221 , and the upper section 22 has a first thread structure on the first thread structure along the longitudinal direction. The direction is provided with spaced grooves 222, and the shape of the grooves can be trapezoidal grooves, rectangular grooves, or curved grooves. The length of the upper section 22 is at least twice the length of the lower section.

As shown in FIG. 6, the corresponding thread protrusions 223 are arranged adjacent to the grooves, and the protrusions here are relative to the grooves, that is, the first thread is at the grooves and the protrusions at the tip to the inner rod. The distances are not the same, and in the grooved part, the distance from the thread crest to the inner rod is also non-uniform. The distance from the tooth crest of the slotted thread 222 to the inner rod is greater than or equal to 0. The maximum width d1 of the longitudinal slot 222 in the radial direction is less than or equal to the maximum width d2 of the threaded protrusion in the radial direction. On the threaded protrusion 223, 1-2 spiral grooves 224 are further provided along the radial direction. This slotted design increases the surface area of the screw in contact with the bone, which can effectively promote osseointegration. In addition, the design of the longitudinal slot structure makes the first thread increase the shear force in the ring direction, which is convenient for nailing. The outer surface of the lower section 23 is provided with a second type of thread, the width of the tooth tip of the second type of thread is smaller than that of the first type of thread, the pitch of the second type of thread is greater than or equal to the pitch of the first type of thread, and the first type of thread is along the The maximum radial depth is the same as the radial depth h of the second thread.

As shown in Figures 5 and 7, a third thread structure is provided on the tail of the upper section, and its pitch is greater than or equal to the second thread pitch. The third thread constitutes at least one quarter of the upper section. The lower section 23 is a hollow structure with an inner thread, the inner thread is matched with the thread of the third type of thread, and the upper and lower sections are locked and connected by threaded fitting. The inner surface of the hollow structure of the lower section 23 can also be designed as a conical surface. The 221 surface replaces the thread with a tapered surface, and the two can also be locked by a taper fit. The screw also includes an elastic threaded outer sleeve 24, the inner side of the elastic threaded outer sleeve 24 is provided with a spiral inner groove, which is sleeved on the third thread at the tail, and the inner diameter of the inner groove of the spiral outer sleeve is larger than the spiral width of the third thread The width is the maximum outer diameter of the thread), and the starting point of the elastic spiral sleeve has a groove that can be stuck in the thread of the tail 221 close to the starting point, so as to ensure the firm connection between the two. In the case of this embodiment, the thread pitch of the inner thread of the hollow structure of the lower section 23 is consistent with the thread pitch of the elastic thread jacket and the third thread. When installing, first set the threaded jacket 24 on the third thread, and then screw it into the lower inner thread, because the inner diameter of the inner groove of the threaded jacket is larger than the helical width of the third thread, which can ensure the adjacent vertebral body. It generates micro-motion during movement, reduces the stress concentration caused by the strong fixation of adjacent segments of the spine, and promotes the integration of bone tissue.

As shown in FIG. 6 , the surface of the thread of the lower half section 3 is provided with a rough structure. The rough surface structure may occupy the entire part of the second type of thread, or may occupy more than half of the surface area of the second type of thread. The rough mesh-like structure A lattice structure is used. In order to make the mesh structure 321 better adhere to the surface of the screw thread of the lower section, it is not easy to displace or fall off as a whole. The rough surface 32 may be formed on the surface of the thread by chemical surface treatment or 3D printing.

In other embodiments, as shown in FIG. 1 , the plate body is arranged in a wavy ridge shape, and the plate hole is arranged at the ridge, which increases the thickness of the plate hole and improves the fixing strength of the screw.

In the embodiment shown in FIG. 9 , there is a lattice structure layer 10 on the bottom surface of the board body, and the lattice structure is a ring-shaped network tetrahedral lattice structure 11 , and two opposite crystals of the lattice structure 11 are formed. The distance between the lattice planes is 0.01-0.05m, preferably 0.02mm, wherein one face of the tetradecahedron is parallel to the bottom face of the plate body. The lattice structure is the basic unit of the composition material. Unlike other three-dimensional network structures, it has better stability and compressive strength while increasing the friction force. In this embodiment, the network structure adopts excellent stability. The annular network tetrahedral lattice structure increases the surface roughness and improves the stability of the plate. One face of the annular network tetradecahedron is substantially parallel to the bottom face of the plate body. The mesh structure corresponds to one tenth of the thickness of the bone plate. Of course, its thickness can also be set to other values. In the present invention, this thickness is set to take into account the overall thickness of the bone plate and the requirements for the fixation strength of the bone plate, to ensure that the notch of the bone plate is not too high, and to effectively improve the holding force of the bone plate on the bone, and improve the fixation strength and stability. sex. The rough structure of the thread surface of the lower half section 3 can be the same lattice structure, wherein one face of the annular mesh tetradecahedron is generally parallel to the longitudinal axis direction of the screw shaft,

The method for manufacturing the above-mentioned fixation system includes the following steps: using a traditional precision casting process to manufacture a bone plate body, and forming a mesh structure on the lower surface of the bone plate; the mesh structure is formed by 3D printing technology, and in the present invention, it is a ring-shaped fourteen-sided A bulk lattice structure with one face parallel to the lower surface of the bone plate.

When using this fixing system, since the nail hole sleeve 5 is made of elastic material, when the screw 2 is screwed into the nail hole sleeve 5, the flanges 52 are pressed against both sides of the nail hole, and after screwing into the nail hole sleeve 5, the flange 52 recovers. In the unsqueezed state, the downward protrusion 53 is located above the groove of the nail head, the height of the protrusion is less than the depth of the groove on the surface of the nail head, and the nail head has a certain degree of mobility in the nail hole sleeve, which can generate fretting and promote Fracture heals; at the same time, if the screw is displaced too much outward, the protrusion 53 on the screw hole sleeve will abut against the groove of the nail head, so that the side and the top have a force to prevent the nail head from withdrawing, and the greater the withdrawal force, the protrusion 53 The fit with the groove 21 will be tighter. Therefore, the technical solution of the present invention is used for the fixation of the spine, through the design of the plate body, the plate holes and the screws, the fixation strength of the bone plate is comprehensively improved, the fretting is allowed, and the fracture healing is promoted.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. A spinal fixation system comprising a bone plate and a screw, The bone plate includes a plate body, a plate hole and a nail hole sleeve inserted into the plate hole; the nail hole sleeve is made of elastic material, and is provided with a joint with the plate hole to prevent the nail hole sleeve from rotating. an engaging part; the nail hole sleeve is provided with a hole penetrating the upper surface and the lower surface of the upper plate for screws to pass through, an inwardly extending flange is provided on the upper surface of the nail hole sleeve, and the lower part of the flange provided with downward projections; At least one of the screws is used to be inserted into the nail hole sleeve, and the upper surface of the nail head of the screw has a groove, which is matched with the protrusion on the nail hole sleeve; the rod part of the screw has an upper section and a lower section, The upper section has a first type of thread, the lower section includes a second type of thread, the crest width of the first type of thread is greater than that of the second type of thread, and the tail of the upper section has a third type of thread. 2 . The spinal fixation system according to claim 1 , wherein the height of the downward protrusion of the nail hole sleeve is smaller than the depth of the groove on the surface of the nail head. 3 . 3 . The spinal fixation system according to claim 1 , wherein the bottom surface and the inner surface of the downward protrusion of the nail hole sleeve are rough surfaces. 4 . 4. The spinal fixation system of claim 1, wherein the length of the upper segment is at least twice the length of the lower segment. 5. The spinal fixation system of claim 1, wherein the third thread constitutes at least one quarter of the upper section. 6 . The spinal fixation system of claim 1 , wherein the lower section has a hollow structure, and the surface of the hollow structure has internal threads. 7 . 7 . The spinal column fixation system according to claim 5 , wherein an elastic threaded outer sleeve is provided in the lower hollow structure, an inner groove is provided on the inner side of the elastic threaded outer sleeve, and the inner groove of the elastic threaded outer sleeve is provided with an inner groove. 8 . The inner diameter is larger than the helical width of the third type of thread, and the third type of thread is provided in the inner groove of the elastic thread jacket to form an integral structure, and is matched and locked with the inner thread. 8 . The spinal fixation system according to claim 1 , wherein the bottom surface of the bone plate body and the outer surface of the second thread have a grid-like structure. 9 . 9. The spinal column fixation system according to claim 7 or 8, wherein the grid-like structure is a grid-like lattice structure, and the distance between two opposite lattice planes of the lattice structure is 0.01-0.05 mm. 10 . The spinal fixation system according to claim 1 , wherein the position of the nail hole of the plate body is a ridge-like protrusion. 11 .

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