CN217660077U - Pedicle screw - Google Patents

Abstract

The utility model discloses a pedicle screw, which comprises a rod body, wherein the rod body comprises a first section and a second section, and the first section is provided with a first thread; the second section is arranged on the rear side of the first section, and a second thread is arranged on the second section; wherein the inner diameter of the first thread is smaller than the inner diameter of the second thread, and the length of the second section is 14-19 mm. The utility model discloses pedicle screw has advantages such as locking taking off and fracture risk is low, can show and reduce postoperative complication, improves postoperative security.

Description

Pedicle screw

Technical Field

The utility model relates to the technical field of medical equipment, concretely relates to pedicle of vertebral arch screw.

Background

The vertebral pedicle screw internal fixation has firm three-dimensional fixation effect, good biomechanical stability and better functions of reduction and deformity correction, and is widely applied to spinal surgery for treating fracture, degenerative change, kyphosis and the like. Pedicle screw loosening is a common complication of pedicle screw internal fixation, and particularly for patients with osteoporosis, the incidence rate is higher. This puts higher demands on the fixing strength of the pedicle screws, and it is urgent to improve the safety of pedicle screw application and reduce the risk of pedicle screw loosening and prolapse.

SUMMERY OF THE UTILITY MODEL

The present invention aims at solving one of the technical problems in the related art at least to a certain extent.

Therefore, the embodiment of the utility model provides a pedicle screw to reduce that pedicle screw is not hard up and deviate from the risk, improve pedicle screw's safety in utilization.

The pedicle screw provided by the embodiment of the utility model comprises a rod body, wherein the rod body comprises a first section and a second section, and the first section is provided with a first thread; the second section is arranged on the rear side of the first section, and a second thread is arranged on the second section; wherein the inner diameter of the first thread is smaller than the inner diameter of the second thread, and the length of the second section is 14-19 mm.

The utility model discloses pedicle screw has advantages such as locking taking off and fracture risk is low, can show and reduce postoperative complication, improves postoperative security.

In some embodiments, the rod body has a diameter of 4.5mm or 5mm and the second section has a length of 14mm.

In some embodiments, the rod body has a diameter of 5.5mm or 6.5mm or 7mm and the second segment has a length of 16mm.

In some embodiments, the rod body has a diameter of 6mm and the second segment has a length of 19mm.

In some embodiments, a ratio of the inner diameter of the first thread to the outer diameter of the first thread is 0.67 to 0.7.

In some embodiments, the ratio of the inner diameter of the second thread to the outer diameter of the second thread is between 0.77 and 0.8.

In some embodiments, the rod body further comprises a transition section, the transition section is arranged between the first section and the second section, a third thread is arranged on the transition section, and the inner diameter of the third thread is gradually increased from front to back.

In some embodiments, the transition section is formed with a transition slope having an inclination angle of 5 ° to 7.5 °.

In some embodiments, the rod body further comprises a tapered section, the tapered section is arranged on the front side of the first section, the diameter of the tapered section is gradually increased from front to back, a fourth thread is arranged on the tapered section, and a self-tapping groove is arranged at the front end of the tapered section.

In some embodiments, at least one of the first and second threads is a double start thread.

Drawings

Fig. 1 is a front view of a pedicle screw according to one embodiment of the invention.

Fig. 2 is a left side view of a pedicle screw according to an embodiment of the invention.

Fig. 3 is a cross-sectional view of a pedicle screw according to one embodiment of the invention.

Fig. 4 is a front view of a pedicle screw according to another embodiment of the invention.

Reference numerals:

pedicle screws 100;

a rod body 10;

a first section 1; a first thread 101;

a second section 2; a second thread 201;

a transition section 3; a third thread 301;

a conical section 4; a fourth thread 401; a self-tapping groove 402;

a screw head 20;

plum blossom holes 5.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

As shown in fig. 1 to 4, a pedicle screw 100 according to an embodiment of the present invention includes a shaft body 10, the shaft body 10 includes a first section 1 and a second section 2, and the second section 2 is disposed at a rear side of the first section 1. The front-back direction is defined according to the sequence of screwing the pedicle screws 100 into the patient when in use, and particularly, when the pedicle screws 100 are in use, one end which is screwed into the patient firstly is the front end, and the other end which is screwed into the patient later is the rear end. The utility model discloses pedicle screw 100 because second section 2 establishes the rear side of first section 1, consequently, first section 1 twists earlier when using in the patient internal, twist behind second section 2 in the patient internal.

The first section 1 is provided with a first thread 101, the second section 2 is provided with a second thread 201, and the length of the second section 2 is 14 mm-19 mm. The inner diameter of the first thread 101 is smaller than the inner diameter of the second thread 201, in other words, the depth of the first thread 101 is larger and the depth of the second thread 201 is smaller, i.e. the depth of the second thread 201 is smaller than the depth of the first thread 101.

The pedicle screw is acted by axial extraction force, transverse buckling force and rotational stress in a body, the loosening and the extraction of the pedicle screw are the results of the comprehensive action of the three stresses, and most biomechanical experiments take the axial extraction force as an index of the holding strength (extraction resistance) of the pedicle screw.

The utility model discloses pedicle screw is when using, the first section cooperates with patient's cancellous bone, and the second section cooperates with patient's cortex bone. The cancellous bone is softer, and more surrounding bone can be occluded by utilizing the first thread with larger depth, so that the pullout resistance of the pedicle screw is improved; the cortical bone is compact and relatively incompressible, the second threads with shallow depth are matched with the cortical bone, the cortical bone is extruded by the second threads, and the pullout resistance of the pedicle screw can be further improved. Moreover, the second section with the larger inner diameter can be used for reducing the fracture risk of the pedicle screw in the cortical bone area.

Furthermore, studies have shown that approximately 60% of the pullout resistance when pedicle screws are secured is dependent on the pedicle portion (second segment) rather than the vertebral body portion (first segment), and that pullout resistance is greatest when the length of the second segment and cortical bone thickness are the same. The utility model discloses pedicle of vertebral arch screw establishes the length of second section into 14mm ~ 19mm for the length of second section is close human cortex bone thickness, can further improve pedicle of vertebral arch screw's resistance to plucking out power.

Therefore, the utility model discloses pedicle of vertebral arch screw has the locking pine and splits advantage such as the risk is low, can show and reduce postoperative complication, improves the postoperative security.

The pedicle screw 100 of the embodiment of the present invention may be a polyaxial pedicle screw (as shown in fig. 1 to 3) or a one-way pedicle screw (as shown in fig. 4).

As shown in FIG. 2, pedicle screw 100 further includes a screw head 20, and a quincuncial hole 5 is formed in screw head 20.

When in specific use, the quincuncial hole 5 can be matched with a nail feeding device, thereby facilitating the implantation of the pedicle screw 100 into a patient.

In some embodiments, the rod body 10 further comprises a tapered section 4, the tapered section 4 is arranged at the front side of the first section 1, the diameter of the tapered section 4 gradually increases from front to back, a fourth thread 401 is arranged on the tapered section 4, and a self-tapping groove 402 is arranged at the front end of the tapered section 4.

For example, as shown in fig. 1, 3 and 4, the rear end of the tapered section 4 is connected to the front end of the first section 1, the rear end of the tapered section 4 has a diameter substantially equal to that of the first section 1, and the self-tapping groove 402 is provided at the front end of the tapered section 4.

Therefore, the tapered section 4 with a small front part and a large back part and the self-tapping groove 402 arranged at the front end of the tapered section 4 facilitate the implantation of the pedicle screw 100 into the body of a patient, and can effectively save the operation time.

Alternatively, two self-tapping grooves 402 are provided, and the two self-tapping grooves 402 are symmetrically arranged along the center line of the rod body 10.

In other embodiments, the quincunx holes may be replaced by hexagonal holes, square holes, etc.

Alternatively, the rod body 10 has a diameter of 4.5mm or 5mm and the second section 2 has a length of 14mm.

For the first (T1) and second (T2) segments of the thoracic vertebrae, the pedicle screws 100, which are clinically commonly used, have a diameter of 4.5mm or 5mm and an average length of 14mm. As shown in table 1, it is found through finite element analysis that the extraction force is the greatest when the length L of the second section 2 is the same as the thickness of the cortical bone, and therefore, setting the length L of the pedicle screw 100 of two specifications of 4.5mm and 5.0mm to 14mm can significantly improve the extraction resistance of the pedicle screw 100, and further reduce the risk of loosening and fracture of the pedicle screw 100, thereby further reducing postoperative complications and improving postoperative safety.

Optionally, the diameter of the shaft body 10 is 5.5mm or 6.5mm or 7mm and the length of the second section 2 is 16mm.

For the third to sixth segments (T3-T6) of the thoracic vertebra, the pedicle screw 100, which is clinically commonly used, has a diameter of 5.5mm, and the average length of the third to sixth segments of the thoracic vertebra is 16mm. As shown in table 1, it is found through finite element analysis that the extraction force is the greatest when the length L of the second section 2 is the same as the thickness of the cortical bone, and therefore, setting the length L of the pedicle screw 100 with the specification of phi 5.5mm to 16mm can significantly improve the extraction resistance force of the pedicle screw 100, further reduce the risk of loosening and fracture of the pedicle screw 100, further reduce postoperative complications, and improve postoperative safety.

For the first to fifth segments (L1-L5) of lumbar spine, the diameter of the pedicle screw 100, which is commonly used clinically, is 6.5mm or 7mm, and the average length of the first to fifth segments of lumbar spine is 16mm. As shown in table 1, it is found through finite element analysis that the extraction force is the greatest when the length L of the second section 2 is the same as the thickness of the cortical bone, and therefore, setting the length L of the pedicle screw 100 of the specification of phi 6.5mm or phi 7mm to 16mm can significantly improve the extraction resistance of the pedicle screw 100, and further reduce the risk of loosening and fracture of the pedicle screw 100, thereby further reducing postoperative complications and improving postoperative safety.

Alternatively, the rod body 10 has a diameter of 6mm and the second section 2 has a length of 19mm.

For the seventh to twelfth segments (T7 to T12) of the thoracic vertebra, the pedicle screw 100, which is clinically commonly used, has a diameter of 6mm, and the average length of the seventh to twelfth segments of the thoracic vertebra is 19mm. As shown in table 1, it is found through finite element analysis that the extraction force is the greatest when the length L of the second section 2 is the same as the thickness of the cortical bone, and therefore, setting the length L of the pedicle screw 100 with the diameter of 6mm to 19mm can significantly improve the extraction resistance of the pedicle screw 100, and further reduce the risk of loosening and fracture of the pedicle screw 100, thereby further reducing postoperative complications and improving postoperative safety.

It should be noted that the segments in table 1 are the number of segments of thoracic vertebrae or lumbar vertebrae, the average length of the pedicle is the thickness of the cortical bone, and the length of the screw thread of the screw corresponding to the cortical bone in the finite element model is the length of the second segment 2. The length L of the thread section (the second section 2) matched with the cortical bone is determined according to the real pedicle length data of different sections of the human body, and the length L is more in accordance with the anatomical data of the human body.

Of course, in other embodiments, the second segment may be set to other lengths matching the actual pedicle length of the different segments of the patient for special (not fit for the average pedicle length of the general population).

TABLE 1 is the pull-out force comparison table of commonly used pedicle screws

Optionally, the ratio of the inner diameter of the first thread 101 to the outer diameter of the first thread 101 is 0.67 to 0.7.

Wherein, the outer diameter of the first thread 101 is equal to the outer diameter of the second thread 201, and the outer diameter of the first thread 101 is equal to the diameter of the rod body 10. As shown in fig. 3, the ratio of the inner diameter D1 of the first thread 101 to the outer diameter D3 of the first thread 101 is 0.67 to 0.7.

From this, when guaranteeing that first section 1 has better structural strength, can make first screw thread 101 darker to make first screw thread 101 can interlock more sclerotin on every side, further improve pedicle of vertebral arch screw 100 resistance to plucking out power, further reduce pedicle of vertebral arch screw 100 and loosen and break risk, thereby further reduce postoperative complication, improve postoperative security.

Optionally, the ratio of the inner diameter of the second thread 201 to the outer diameter of the second thread 201 is 0.77 to 0.8.

Wherein, the outer diameter of the second thread 201 is equal to the outer diameter of the first thread 101, and the outer diameter of the second thread 201 is equal to the diameter of the rod body 10. As shown in fig. 3, the ratio of the inner diameter D2 of the second thread 201 to the outer diameter D3 of the second thread 201 is 0.77 to 0.8.

From this, the internal diameter of second screw thread 201 is great, and extrusion cortex bone that can be better obtains higher resistance to pull out power to can reduce disconnected nail risk, further reduce pedicle of vertebral arch screw 100 and loosen and take off and fracture risk, thereby further reduce postoperative complication, improve postoperative security.

In some embodiments, the rod body 10 further comprises a transition section 3, the transition section 3 is arranged between the first section 1 and the second section 2, the transition section 3 is provided with a third thread 301, and the inner diameter of the third thread 301 is gradually increased from front to back.

For example, as shown in fig. 1, 3 and 4, the front end of the transition section 3 is connected to the first section 1, and the rear end of the transition section 3 is connected to the second section 2. The depth of the third thread 301 increases gradually from front to back, the depth of the front end of the third thread 301 is substantially equal to the depth of the first thread 101, and the depth of the back end of the third thread 301 is substantially equal to the depth of the second thread 201.

Therefore, the transition section 3 and the third thread 301 arranged on the transition section 3 are utilized to realize the conical transition between the two sections of threads (the first thread 101 and the second thread 201), so that the second section 2 can be conveniently screwed into the conical bone, and the operation time can be effectively saved.

Optionally, the transition section 3 is formed with a transition slope, and the inclination angle of the transition slope is 5 ° to 7.5 °.

For example, as shown in fig. 3, the transition section 3 is formed with a transition slope at the root of the third thread 301, and the transition slope is a tapered surface as a whole. The inclination angle of the transition inclined plane is 5 to 7.5 degrees, and the cone angle theta of the cone on which the conical surface is positioned is understood to be 10 to 15 degrees.

Therefore, the inclination angle of the transition inclined plane is set to be 5-7.5 degrees, compared with the pedicle screw with the same specification in the related technology, the anti-pulling force can be improved by 20-24 percent, the risk of loosening the pedicle screw 100 is further reduced, the postoperative complications are further reduced, and the postoperative safety is improved.

Optionally, the first thread 101, the second thread 201, the third thread 301, and the fourth thread 401 are each double start threads. In other words, the first thread 101, the second thread 201, the third thread 301, and the fourth thread 401 are all double-start threads.

Therefore, the pedicle screw 100 is designed to be double-line in the whole process, the screw feeding speed of the pedicle screw 100 can be increased, and the operation time is effectively saved.

Of course, in other embodiments, the first thread, the second thread, the third thread, and the fourth thread may be a single start thread or other number of multiple start threads. In addition, the number of the first thread, the second thread, the third thread and the fourth thread may be equal or unequal.

In the pedicle screw 100 of the embodiment of the present invention, the tapered section 4 is provided with the self-tapping groove 402, which facilitates the pedicle screw 100 to be screwed into the patient; the inner diameter of the thread corresponding to the first section 1 of the cancellous bone is smaller, so that more peripheral bone can be occluded, and the anti-extraction force is improved; the inner diameter of the thread of the second section 2 corresponding to the cortical bone is larger, so that the cortical bone can be extruded, higher pull-out resistance is obtained, and the risk of broken nails can be reduced; the pedicle screw 100 has a double-thread design in the whole process, so that the screw fast feeding speed can be increased, and the operation time can be shortened.

In the description of the present invention, it is to be understood that "diameter" herein refers to the outer diameter of the screw; the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the indicated orientations and positional relationships of the illustrated figures for ease of description and simplicity of description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In the present application, unless expressly stated or limited otherwise, a first feature "on" or "under" a second feature may be directly contacting the second feature or the first and second features may be indirectly contacting the second feature through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.

Claims (10)

1. A pedicle screw, comprising a shaft body, the shaft body comprising:

the first section is provided with a first thread; and

the second section is arranged on the rear side of the first section, and a second thread is arranged on the second section;

wherein the inner diameter of the first thread is smaller than the inner diameter of the second thread, and the length of the second section is 14-19 mm.

2. Pedicle screw according to claim 1, wherein the rod body has a diameter of 4.5mm or 5mm and the second section has a length of 14mm.

3. Pedicle screw according to claim 1, wherein the diameter of the shaft body is 5.5mm or 6.5mm or 7mm and the length of the second section is 16mm.

4. The pedicle screw according to claim 1, wherein the shaft has a diameter of 6mm and the second section has a length of 19mm.

5. The pedicle screw according to any one of claims 1-4, wherein a ratio of an inner diameter of the first thread to an outer diameter of the first thread is between 0.67 and 0.7.

6. The pedicle screw according to any one of claims 1-4, wherein a ratio of an inner diameter of the second thread to an outer diameter of the second thread is between 0.77 and 0.8.

7. The pedicle screw according to any one of claims 1-4, wherein the shaft further comprises a transition section disposed between the first section and the second section, the transition section having a third thread thereon, the third thread having an inner diameter that gradually increases from anterior to posterior.

8. The pedicle screw according to claim 7, wherein the transition section is formed with a transition bevel having an inclination angle of 5 ° to 7.5 °.

9. The pedicle screw according to any one of claims 1 to 4, wherein the shaft further comprises a tapered section provided at a front side of the first section, the tapered section having a diameter gradually increasing from front to back, the tapered section being provided with a fourth thread, and a front end of the tapered section being provided with a self-tapping groove.

10. The pedicle screw according to any one of claims 1-4, wherein at least one of the first and second threads is a double start thread.

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