CN203564323U - Improved vertebral pedicle extending device - Google Patents

Abstract

The utility model relates to an improved pedicle extension device, which is composed of a core rod and a front nail body and a rear nail body which are threadedly connected to both ends of the core rod respectively, wherein the outer surfaces of the front nail body and the rear nail body are designed There are self-tapping threads with equal pitches, and it is characterized in that an insertion structure is provided between the front nail body and the rear nail body, and when the two are inserted together, a pedicle screw is formed; the vertebral arch The root screw is provided with a threaded hole along the axis line, and the internal thread in the threaded hole has the same direction of rotation, and the pitch of the internal thread in the rear nail body is greater than the pitch of the internal thread in the front nail body; the two ends of the core rod There are external threads matching the internal threads in the front nail body and the rear nail body respectively, the middle part is a polished rod, and the length of the core rod is equal to the vertebra formed by the insertion of the front nail body and the rear nail body. The sum of the length of the pedicle screw and the preset extension length of the pedicle. The device can not only avoid the risk of pushing the vertebral body to move away from the pedicle, but also has the advantage of stability.

Description

An improved pedicle extension device

technical field

The utility model relates to a medical surgical instrument, in particular to a spinal internal fixation device, which is suitable for cutting and lengthening the vertebral pedicle.

Background technique

Lumbar spinal stenosis refers to a series of diseases caused by various reasons such as intervertebral disc herniation, bone hyperplasia or fibrous tissue hyperplasia, hypertrophy leading to narrowing of the spinal canal or nerve root canal or intervertebral foramen, stimulation and compression of nerve roots or cauda equina Clinical symptoms. The typical clinical manifestations of lumbar spinal stenosis are: low back pain, neurogenic claudication, intermittent radiating pain in the lower limbs, aggravated by standing for a long time, active or lumbar hyperextension, and relieved when sitting, lying or lumbar flexion. Conservative treatment of patients with lumbar spinal stenosis often fails to improve symptoms, and surgical methods are often used to solve the problem.

Most of the surgical methods currently used in clinical practice are partial or complete excision and decompression of the lamina and articular process through the posterior approach, internal fixation with pedicle screws, and intervertebral fusion, so as to expand the spinal canal and intervertebral foramen, and achieve the release of nerve tension. purpose of oppression. In practical application, when the pedicle screw internal fixation device is used, there are often complications such as internal fixation failure and aggravated degeneration of adjacent segments. The surgery rate is high.

Minimally invasive surgery is an inevitable trend in the development of surgery. Minimally invasive treatments for lumbar spinal stenosis include percutaneous screw-rod system placement, spinous process distraction, and pedicle lengthening. The pedicle extension and fixation device expands the area of the spinal canal and intervertebral foramen by extending the severed pedicle, and improves clinical symptoms. The fixation device can improve the minimally invasive degree of laminoplasty, improve the accuracy of screw placement, reduce surgical trauma, shorten the operation and postoperative recovery time, and the like.

The invention patent application with the publication number CN101695453A discloses a pedicle extension device, which includes a front nail, a core rod, a rear nail and a fixator. The front end of the core rod is threadedly connected with the front nail, the rear end of the core rod is sleeved with the rear nail, and the core rod is slidingly connected with the rear nail; fixed. The solution described in the above-mentioned patent application uses the threads on the surface of the back nail to fix the back nail on the severed pedicle, and then twist the fixator (nut) to make the core rod and the front nail slide forward in the back nail, thereby pushing the vertebral body. Move away from the pedicle to achieve the purpose of expanding the spinal canal and intervertebral foramen. But the scheme described in the above-mentioned patent application still has the following deficiencies: (1) the thread on the surface of the back nail not only bears the task of connecting the pedicle but also bears the task of the fixator (nut) (see Fig. 2 of the patent application), Therefore, self-tapping threads cannot be selected for the thread on the surface of the posterior nail, and the connection between the posterior nail and the pedicle is obviously not reliable enough; (2) There is a relatively large fit gap between the mandrel and the posterior nail, and the After the pedicle is stretched, the core rod and the fixer (nut) cannot be fixed together, so under the action of external force, the core rod together with the vertebral body can not only shake, but also continue to move away from the fixer (nut) (promoting the vertebral body to move away from the pedicle), so there are obvious defects of poor fixation and poor stability; (3) the front nail is only inserted in the installation guide hole, and there is also the vertebral body moving away from the fixator (nut ) risk of moving in the direction.

The scheme described in the utility model patent application with the authorized announcement number CN201912218U is improved by adding a scale on the basis of the scheme described in the invention patent application with the publication number CN101695453A, so there are also the shortcomings of the above-mentioned invention patent application with the publication number CN101695453A.

Contents of the invention

In view of the above shortcomings in the prior art, the technical problem to be solved by the utility model is to provide an improved pedicle extension device, which can not only avoid the risk of pushing the vertebral body away from the pedicle, but also has The advantage of stability.

The scheme that the utility model solves the problems of the technologies described above is as follows:

An improved pedicle extension device, which is composed of a core rod and a front nail body and a rear nail body which are threadedly connected to both ends of the core rod respectively, wherein the outer surfaces of the front nail body and the rear nail body are provided with equal pitch The self-tapping thread is characterized in that an insertion structure is provided between the front nail body and the rear nail body, and a pedicle screw is formed when the two are inserted together; The center line is provided with a threaded hole, the internal thread in the threaded hole has the same direction of rotation, and the pitch of the internal thread in the rear nail body is greater than the pitch of the internal thread in the front nail body; the two ends of the core rod are respectively provided with The external thread matched with the internal thread set in the front nail body and the rear nail body, the middle part is a polished rod, and the length of the core rod is equal to the length of the pedicle screw formed by inserting the front nail body and the rear nail body together. The sum of the length and the preset extension length of the pedicle.

In the above-mentioned technical solution of the utility model, since the task undertaken by the plug-in connection structure is to insert the front nail body and the rear nail body when the formed pedicle screw is screwed into the lumbar vertebrae from the guide hole, The required torque can be provided, so the plug-in connection structure can be various connection structures that can provide the torque, and there are the following two ideal solutions in this structure. in,

The first scheme is that, in the heads of the front nail body and the rear nail body, one head has an outer hexagon, and the other head is provided with an inner hexagon that matches the outer hexagon; and, the front nail body and the rear nail body After the back nail bodies are plugged together, the self-tapping threads provided on the outer surfaces of the two are continuous.

Another solution is that, on the opposite end faces of the front nail body and the rear nail body, fan-shaped claws and fan-shaped grooves are respectively staggered, and the cross-sections of the fan-shaped claws and the fan-shaped grooves are fan-shaped with the same shape and equal area; Moreover, after the front nail body and the rear nail body are plugged together, the self-tapping threads provided on the outer surfaces of the two are cut off within the length interval of the fan-shaped claw for the same helical thread.

In the above-mentioned technical solution of the present invention, the core rod can be provided with a central hole along the axis, and some small holes can also be distributed on the surface of the front nail body, so as to pass through the central hole and small holes during the operation. The formed channel pours some bone cement into the bone body to strengthen the loose bone. These are easily conceivable by those of ordinary skill in the art.

Compared with the common pedicle screw, the improved pedicle extension device described in this utility model has a significant difference in that the pedicle screw consists of a front nail body and a rear nail body, except that a mandrel is added. Therefore, if the self-tapping threads on the outer surface are misplaced after the two are inserted, the thread teeth tapped by the front nail body on the lumbar vertebrae will be damaged by the rear nail body during the tapping process. In order to solve the above technical problems, a reliable method recommended by the inventor is to insert the front nail body and the rear nail body and fix them together (as shown in Figure 1) before processing the self-tapping thread, and then once The tool feeds the self-tapping threads on the surface of the front and rear nail bodies.

In addition, in the improved pedicle extension device described in the present invention, the pitch of the internal thread in the rear nail body is greater than the pitch of the internal thread in the front nail body, and there is a gap between the front nail body and the rear nail body. Plug-in connection structure, so after screwing the front nail body and the rear nail body to the core rod from both ends, the front nail body and the rear nail body must be fixed to prevent them from rotating and the core rod can be twisted to use the inside of the rear nail body. The pitch difference between the thread and the internal thread in the front nail body inserts the front nail body and the rear nail body together.

Compared with the prior art, the pedicle extension device described in the utility model has the following beneficial effects:

1. The outer surface of the front nail body and the rear nail body is provided with self-tapping threads with equal pitch. When the two are plugged together, a pedicle screw is formed, and the rear nail body and the mandrel are also threaded. The risk of vertebral body movement along the mandrel axis is thus avoided.

2. The connection between the posterior nail and the pedicle adopts self-tapping thread, which can withstand large axial force and is relatively stable and reliable.

3. The pitch of the internal thread in the rear nail body is greater than the pitch of the internal thread in the front nail body, so when the mandrel is twisted, it is equivalent to pushing the broken pedicle backward, which is more in line with the physiology of the human body than the existing technology feature.

4. The length of the mandrel is equal to the sum of the depth of the blind hole and the preset extension length of the pedicle. Therefore, after the disconnected pedicle is stretched by the preset distance, the mandrel will not be retracted into the front screw body, obviously Improved overall fixation stability.

Description of drawings

Figures 1 and 2 are schematic structural views of a specific embodiment of the improved pedicle extension device described in the present invention; wherein Figure 1 is a front view, and Figure 2 is a cross-sectional view of A-A of Figure 1 (enlarged).

Fig. 3 is a structural schematic diagram of the front nail body and the rear nail body in the embodiment shown in Fig. 1 and Fig. 2, and the arrows in the figure indicate the insertion direction of the two.

Fig. 4 is a schematic structural view of the core rod in the embodiment shown in Fig. 1 and Fig. 2 .

Fig. 5 and Fig. 6 are the installation state diagrams of the improved pedicle extension device of the present invention; wherein Fig. 5 is a state diagram before the pedicle is extended, and Fig. 6 is a state diagram after the pedicle is extended.

Fig. 7 and Fig. 8 are structural schematic diagrams of another specific embodiment of the improved pedicle extension device of the present invention; Fig. 7 is the front view, and Fig. 8 is the BB section view (enlarged) of Fig. 7 .

Fig. 9 is a structural schematic diagram of the front nail body and the rear nail body in the embodiment shown in Fig. 7 and Fig. 8, and the arrows in the figure indicate the insertion direction of the two.

Detailed ways

example 1

Referring to Fig. 1 and Fig. 2, the entire pedicle extension device is composed of a mandrel 1 and a front nail body 2 and a rear nail body 3 which are threadedly connected to both ends of the mandrel 1, wherein the outer surfaces of the front nail body and the rear nail body are Self-tapping threads with equal pitch.

Referring to Fig. 3 and in conjunction with Fig. 2 and Fig. 1, in the relative head of front nail body 2 and rear nail body 3, the head of front nail body 2 is provided with inner hexagon 4, and the head of rear nail body 3 is provided with front nail body 3. The head of the nail body 2 is provided with an outer hexagon 5 that matches the inner hexagon. The inner hexagon 4 and the outer hexagon 5 constitute the plug-in structure between the front nail body 2 and the rear nail body 3. After the front nail body 2 and the rear nail body 3 are plugged and connected, a pedicle screw is formed, and the two The self-tapping thread provided on the outer surface is continuous (see Figure 1).

Referring to Fig. 3, the pedicle screw formed after the front nail body 2 and the rear nail body 3 are plugged and connected is provided with a threaded hole 6 along the axis line. The pitch of the internal thread in the nail body 3 is greater than the pitch of the internal thread in the front nail body 2 .

Referring to Fig. 4, the two ends of the core rod 1 are respectively provided with external threads matching the internal threads of the front nail body 2 and the rear nail body 3, and the middle part is a polished rod; the length of the core rod 1 is equal to that of the front nail body 2 and the rear nail body 3 The sum of the length of the pedicle screw formed by inserting the rear nail bodies 3 together and the preset extension length of the pedicle.

Referring to Fig. 5 and Fig. 6 in combination with Fig. 1, the installation method of the improved pedicle extension device described in the present invention is as follows:

(1) Use a pistol drill to drill a guide hole on the pedicle 11 that needs to be extended on the lumbar vertebra 10;

(2) Install the front nail body 2 and the rear nail body 3 on the mandrel 1 and make the front nail body 2 and the rear nail body 3 tightly inserted together (as shown in Figure 1) to form a pedicle extension device 9 , and then drive the whole device into the lumbar vertebra 10 along the guide hole (see Figure 5);

(3) Disconnect the pedicle 11, twist the mandrel 1 so that it retracts into the rear nail body 3 and ensure that the heads of the two are flush (see Figure 6).

Example 2

Referring to FIG. 7 and FIG. 8 , in this embodiment, the insertion structure between the front nail body 2 and the rear nail body 3 is different, and other structures are the same as in Example 1. In this embodiment, the plug-in structure is composed of fan-shaped claws 7 and fan-shaped grooves 8 arranged alternately on the opposite end faces of the front nail body 2 and the rear nail body 3, wherein the fan-shaped claws 7 and the fan-shaped grooves 8 The cross-sections are fan-shaped with the same shape and equal area. After the front nail body 2 and the rear nail body 3 are plugged together, the self-tapping threads provided on the outer surfaces of the two are cut off within the length interval of the sector claw 7 for the same helical thread.

Claims (3)

1. An improved pedicle extension device comprises a core rod, a front nail body and a rear nail body which are respectively in threaded connection with two ends of the core rod, wherein self-tapping threads with the same thread pitch are arranged on the outer surfaces of the front nail body and the rear nail body; the pedicle screw is provided with a threaded hole along the axial lead, the turning directions of internal threads in the threaded hole are the same, and the pitch of the internal threads in the rear screw body is greater than that in the front screw body; the two ends of the core rod are respectively provided with external threads matched with the internal threads arranged in the front nail body and the rear nail body, the middle part of the core rod is a polished rod, and the length of the core rod is equal to the sum of the length of a pedicle screw formed by splicing the front nail body and the rear nail body and the preset and extended length of the pedicle screw.

2. The improved pedicle extension device according to claim 1, wherein the insertion structure is: in the heads of the front nail body and the rear nail body, one head is provided with an outer hexagon, and the other head is provided with an inner hexagon matched with the outer hexagon; and after the front nail body and the rear nail body are spliced together, self-tapping threads arranged on the outer surfaces of the front nail body and the rear nail body are continuous.

3. The improved pedicle extension device according to claim 1, wherein the insertion structure is: sector claws and sector grooves are respectively arranged on the opposite end surfaces of the front nail body and the rear nail body in a staggered manner, and the cross sections of the sector claws and the sector grooves are sectors with the same shape and the same area; and after the front nail body and the rear nail body are spliced together, self-tapping threads arranged on the outer surfaces of the front nail body and the rear nail body are separated from each other by the same spiral thread in the length interval of the fan-shaped claw.

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