CN109124748A - A kind of spongious screw - Google Patents

Abstract

The present invention proposes a kind of spongious screw, including screw body (1), and the surface of screw body (1) has porous structure.After the screw pedicle implantation, the porous structure of screw will increase the contact area of itself and sclerotin around, improve its skin-friction force, enhance the anti-pull-out strength of screw.

Description

a porous screw

technical field

The invention belongs to the technical field of biomedical materials, in particular to a porous screw.

Background technique

Spine trauma, degeneration, tumors and other diseases often require surgical treatment. The use of pedicle screws helps to maintain the stability of the spine after surgery and provides favorable conditions for the realization of spinal fusion. However, with the wide application of pedicle screws, the related complications have gradually been recognized, among which the early pull-out and later loosening of pedicle screws is a problem that cannot be ignored. With the development of medical technology and the aging of the population, the number of elderly patients undergoing spinal surgery is gradually increasing, which means that the population of patients undergoing osteoporosis surgery is also gradually increasing. Coupled with the increase in the level of daily activities, the existence of these factors will It increases the risk of early withdrawal and later loosening of pedicle screws after surgery. The removal or loosening of the screw will often bring obvious discomfort to the patient again, and even cause the spinal cord nerve compression, thus requiring another surgical treatment, which will significantly increase the treatment cost and hinder the patient's recovery.

Pedicle screws are mainly composed of a screw body and a U-shaped screw cap. The pedicle screws currently used in clinical use mainly maintain their pull-out strength through thread fixation. The surface of the screw body is mostly a smooth metal interface. The frictional force is lower, and the pullout resistance of the screw will be significantly reduced when encountering patients with more severe osteoporosis (or when the screw path needs to be readjusted due to the poor position of the initial screw placement).

In addition, since most of the currently used screws are solid structures, the screws cannot achieve bone ingrowth in the later stage, and the interface between the screw and the bone always exists, which is one of the reasons for the screw loosening in the later stage.

To sum up, the early screw pullout and later screw loosening after pedicle screw implantation are one of the problems that cannot be ignored in current spine surgery.

SUMMARY OF THE INVENTION

In view of the problems in the background art, the present invention provides a porous screw, which includes a screw body, and the surface of the screw body has a porous structure.

Optionally, the screw body includes a head section and a middle section, the middle section to the head section is a gradually changing structure from solid to porous, and the head section or a part of the head section is a porous structure.

Optionally, the screw main body includes a tail section, the tail section is a solid structure, and the outer periphery of the screw main body is provided with a threaded structure.

Optionally, the interior of the head section is a solid structure, and the outer surface of the head section is a porous structure.

Optionally, the inner and outer surfaces of the head section are porous structures.

Optionally, the multi-hole screw further comprises: a hole, the hole is located inside the screw body and extends axially from the tail section to the head section.

Optionally, the multi-hole screw further comprises: a side hole, the side hole extending from the hole.

Optionally, the side holes are located in the head section of the screw body.

Optionally, the side holes pass through or are isolated from the porous structure.

Optionally, the porous screw further comprises: a U-shaped nail tail, the interior of the U-shaped nail tail has a built-in threaded structure, wherein the hole extends to the U-shaped nail tail.

The beneficial effects of the present invention include:

After the screw is implanted through the pedicle, the porous structure of the screw will increase the contact area with the surrounding bone, improve its surface friction, and enhance its pull-out strength.

In a preferred manner, the solid structure of the screw is maintained at the tail portion of the screw body where the stress is relatively concentrated, so as to maintain its mechanical strength and reduce the risk of screw breakage. In addition, the gradient structure from solid to porous is beneficial to reduce the phenomenon of local stress concentration.

In a preferred way, bone cement can be injected through the central hole to improve its pull-out strength, and the porous structure in the later stage can promote bone ingrowth and realize the integration of the screw and the vertebral body, so as to reduce the early pull-out and later loosening of the screw risks of.

Description of drawings

1 is a schematic structural diagram of an embodiment of the porous pedicle screw of the present invention;

Figure 2 is a cross-sectional view of the porous pedicle screw in Figure 1;

3 is a schematic structural diagram of another embodiment of the porous pedicle screw of the present invention;

Figure 4 is a cross-sectional view of the porous pedicle screw in Figure 3;

5 is a schematic structural diagram of another embodiment of the porous pedicle screw of the present invention;

6 is a schematic structural diagram of another embodiment of the porous pedicle screw of the present invention;

7 is a schematic structural diagram of another embodiment of the porous pedicle screw of the present invention;

FIG. 8 is a schematic structural diagram of another embodiment of the porous pedicle screw of the present invention.

in,

1- Screw body, 2- U-shaped nail cap, 11- Head section, 12- Middle section, 13- Tail section, 14- Thread structure, 15- Hole, 16- Side hole, 21- Thread structure.

Detailed ways

Embodiments of the present invention are described below with reference to the accompanying drawings, wherein like components are designated by like reference numerals. In the case of no conflict, the following embodiments and technical features in the embodiments can be combined with each other.

first embodiment

As shown in FIGS. 1-2 , the porous screw of the present invention includes: a screw body 1 and a U-shaped nail cap 2 .

The inside of the U-shaped nail tail 2 has a built-in thread structure 21 . The screw body 1 is provided with an external thread structure 14 . The tail section 13 of the screw body 1 is a non-porous solid structure.

The head section 11 and the middle section 12 of the screw main body 1, from the middle section 12 to the head section 11, are of a gradually changing structure from solid to porous.

In addition, the head section 11 and the middle section 12 of the screw main body 1 have a gradual structure from solid to porous from the inside to the outside.

The invention changes the main part of the screw into a porous structure, increases the contact area between the screw and the surrounding bone, improves its surface friction, and further enhances the stability of the screw. Changing the surface of the main part of the screw to a porous structure can promote the growth of the surrounding bone into the porous part of the screw, making the integration of the screw and the bone possible, thereby reducing the risk of screw loosening in the later stage.

After the screw is changed to a porous structure, its strength will decrease, so the tail section of the screw body where the stress is relatively concentrated can maintain a solid structure to maintain its strength and reduce the risk of screw fracture. In addition, the screw body of the present invention has a gradual structure from solid to porous, which is beneficial to reduce the phenomenon of local stress concentration.

Second Embodiment

3-4 show another embodiment of the present invention, the design idea of which is similar to the first embodiment, the difference is that in the head section 11 and the middle section 12 of the screw body 1, the middle section 12 to the head section 11 is from solid to porous Gradient structure. From the inside to the outside, the structure is gradually changed from solid to porous, the porous structure is located on the outer periphery of the screw body 1 , and the solid structure is located inside the screw body 1 . In addition, a certain portion F of the front end of the head section 11 is all porous.

The shape, length, gradation manner, etc. of the graded regions of the solid structure and the porous structure described in the first and second embodiments can be modified in various ways.

Third Embodiment

5-8 show another embodiment of the present invention, the design idea of which is similar to the first and second embodiments, the difference is that in this embodiment, a hole 15 and a side hole 16 are provided in the center of the screw body 1 . The tunnel 15 extends to the staple cap 2 for injection of bone cement.

In the embodiment shown in FIGS. 5-6 , the hole 15 is located in the center of the screw body 1 and extends along the axial direction of the screw body 1 . The hole 15 and the side holes 16 and the porous structure of the screw body 1 communicate with each other or are isolated from each other. The hole 16 can lead to the outer surface of the screw body 1 . In this embodiment, the hole 15 runs through a part of the tail section 13 , the middle section 12 and the head section 11 of the entire screw body 1 . The difference between the embodiments shown in Figures 5-6 is the transition of the head section 11 from a solid structure to a porous structure. In the embodiment shown in FIG. 5 , the center of the head section 11 is a solid structure. In the embodiment shown in FIG. 6 , a part of the head section 11 is a porous structure from the inside to the outside (from the axis to the outer surface). .

In the embodiment shown in FIGS. 7-8 , the difference from the embodiment shown in FIGS. 5-6 is that the side hole 16 extends from the hole 15 , and the hole 15 and the side hole 16 communicate with the porous structure of the screw body 1 . , that is, the side holes 16 only extend to the porous structure and communicate with the porous structure. In the embodiment shown in FIG. 7 , the center of the head section 11 is a solid structure. In the embodiment shown in FIG. 8 , a part of the head section 11 is a porous structure from the inside to the outside (from the axis to the outer surface). .

In the present invention, longitudinal holes and side holes are arranged in the center of the screw main body, the central hole and the side holes and the porous part are mutually connected or isolated from each other, and the stability of the screw can be enhanced by injecting bone cement through the central hole.

The above-mentioned embodiments are only preferred specific embodiments of the present invention, and the usual changes and substitutions made by those skilled in the art within the scope of the technical solutions of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A porous screw comprising a screw body (1), characterized in that,

the surface of the screw body (1) has a porous structure.

2. The multi-hole screw of claim 1,

the screw main body (1) comprises a head section (11) and a middle section (12), the structure gradually changes from a solid body to a plurality of holes from the middle section (12) to the head section (11), and the head section (11) or a part of the head section (11) is of a porous structure.

3. The multi-hole screw of claim 2,

the screw main body (1) further comprises a tail section (13), the tail section (13) is of a solid structure, and a thread structure (14) is arranged on the periphery of the screw main body (1).

4. The multi-hole screw of claim 2,

the interior of the head section (11) is of a solid structure, and the outer surface of the head section (11) is of a porous structure.

5. The multi-hole screw of claim 2,

the inner and outer surfaces of the head section (11) are of porous structure.

6. The multi-hole screw of claim 1, further comprising:

and the pore channel (15) is positioned inside the screw main body (1) and axially extends from the tail section (13) to the head section (11).

7. The multi-hole screw of claim 6, further comprising:

side holes (16), the side holes (16) extending from the tunnel (15).

8. The multi-hole screw of claim 7,

the side hole (16) is located in the head section (11) of the screw body (1).

9. The multi-hole screw of claim 7,

the side holes (16) are through or isolated from the porous structure.

10. The multi-hole screw of claim 6, further comprising:

the U-shaped nail tail (2) is internally provided with a built-in thread structure (21), and the pore canal (15) extends to the U-shaped nail tail (2).