CN114404010A - Adjustable vertebral lamina hook internal fixation device for lumbar isthmus fissure - Google Patents

Abstract

The invention discloses an adjustable laminar hook internal fixation device for lumbar spondylolisthesis, belonging to the technical field of medical devices, comprising a pedicle screw, which is connected with a laminar hook through a connecting rod assembly; the connection The rod assembly includes a first connecting rod fixedly connected with the pedicle screw, the first connecting rod and the second connecting rod are rotatably connected, the second connecting rod has a hollow structure for the third connecting rod to penetrate therein, and the third connecting rod is It can move axially along the second connecting rod, and the third connecting rod and the lamina hook are rotatably connected.

Description

An adjustable laminar hook internal fixation device for lumbar spondylolysis

technical field

The invention relates to the technical field of medical devices, in particular to an adjustable laminar hook internal fixation device for lumbar spondylosis.

Background technique

The statements herein merely provide background related to the present invention and do not necessarily constitute prior art.

Lumbar spondylosis is a common clinical spinal injury disorder, mainly caused by congenital causes and traumatic stress. Lumbar spondylolisthesis has a higher incidence in youth, especially in people who exercise vigorously or overwork. When lumbar spondylolisthesis occurs, symptoms such as low back pain and nerve numbness will occur, resulting in inconvenience for patients to move, and even more serious symptoms such as lumbar spondylolisthesis.

Clinically, there are various strategies for the treatment of lumbar spondylolysis, and surgical treatment is performed for patients who are not ideal after conservative treatment. Because segmental fusion accelerates the degeneration of the adjacent intervertebral disc, direct repair of the isthmus is commonly used. At present, the widely used direct repair of isthmus is isthmic bone graft fusion combined with single-segment internal fixation, which can solve the stress shielding effect of cross-segment internal fixation on adjacent segments. The surgical methods that have entered the clinic are as follows. .

One is Buck screw fixation. This method is to insert screws between the fractured isthmus and the lamina, which can restore the connection of the isthmus, but it also reduces the amount of bone graft, which is not conducive to bone graft fusion, and the isthmus is significantly stressed. Increase, the screw is unstable, and the screw needs to be accurately positioned, and the operation is complicated and easy to fail; the other is the Nicol wire binding method, which uses a steel wire to bind and fix the transverse process and the spinous process. Injury to nerve ligaments and other tissues, difficult to operate, and many postoperative complications; there is also a Morscher screw hook fixation method, which is to place a pedicle screw on the upper edge of the vertebral body and a lamina on the lower edge of the fractured isthmus lamina. hook, and connect and fix by connecting rod. This pedicle screw and laminar hook fixation method can effectively pressurize the isthmus bone graft, the surgical trauma is small, and the normal physiological activities of the spine are not affected. The stability and fusion rate are higher than the previous two methods, and the clinical therapeutic effect is Significantly.

The inventor found that although the current laminar hook internal fixation device has been improved by many scholars, it still has many shortcomings: the spinal structure of different patients is different, which cannot meet individual needs; when the pedicle screw placement position remains unchanged, the corresponding vertebral The plate hook may not be accurately hooked on the lower edge of the lamina. In this case, the connecting rod needs to be pre-bent to match, which requires tool assistance and the state of the connecting rod is difficult to control, which is time-consuming and labor-intensive. The direction and angle adjustment of the internal fixation device is complicated, and the connecting rod cannot be adjusted during the operation. The angle cannot adapt to the position of the lamina hook; the connecting rod cannot meet the requirement of being in the same plane after bending, and the unbalanced force of the internal fixation device causes the fixation failure; the structure of the connecting rod and the lamina hook is complex and changeable, and the occupation of space leads to bone grafting Insufficient amount; the length of the connecting rod between the screw and the lamina hook is determined. When the length needs to be increased or decreased to fix the device, the length can only be adjusted by rotating the nut or the connecting rod or the lamina hook can be replaced. The adjustment method is complicated and may cause problems. This leads to the expansion of the surgical trauma area; most of the lamina hooks have connectors, which take up a lot of space. In addition, the opening angle of the lamina hooks is fixed, and the laminar hooks may become loose due to poor fit between the lamina hooks and the lamina.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide an adjustable laminar hook internal fixation device and method for lumbar spondylolysis, which can achieve three coronal angle adjustment, length adjustment, and coronal vertical angle adjustment. The controllable functional adjustment meets the needs of adjustment during surgery, and solves the problem that the existing laminar hook internal fixation device cannot adapt to the differences in the spinal structure of different patients and cannot meet the needs of different individuals.

In order to achieve the above object, the present invention is realized by the following technical solutions:

In a first aspect, the present invention proposes an adjustable laminar hook internal fixation device for lumbar spondylosis, comprising a pedicle screw, which is connected to the laminar hook through a connecting rod assembly; the connecting rod assembly includes The first connecting rod is fixedly connected with the pedicle screw, the first connecting rod and the second connecting rod are connected in rotation, the second connecting rod has a hollow structure for the third connecting rod to penetrate into it, and the third connecting rod can pass along the first connecting rod. The two connecting rods move axially, and the third connecting rod and the lamina hook are rotatably connected.

As a further technical solution, the rotation plane where the first connecting rod and the second connecting rod are located is perpendicular to the rotation plane where the third connecting rod and the lamina hook are located.

As a further technical solution, a locking ring is arranged in the hollow structure of the second connecting rod, and the locking ring is sleeved on the third connecting rod.

As a further technical solution, the inner side of the locking ring is provided with serrations, the third connecting rod is provided with a serrated rod, the serrated rod penetrates into the hollow structure and the locking ring, and the serrated rod and the serrations of the locking ring are engaged.

As a further technical solution, a screw rod is fixed on the side of the locking ring, a slot hole is formed on the side wall of the second connecting rod, and the screw rod passes through the slot hole and is fixedly connected with the fastener.

As a further technical solution, the tail of the pedicle screw is provided with a U-shaped groove for the first connecting rod to pass through.

As a further technical solution, the U-shaped groove of the pedicle screw is fixedly connected with the locking member.

As a further technical solution, a first thread is provided on the outer side of the locking piece, a second thread is provided on the head of the pedicle screw, a third thread is provided on the inner wall of the U-shaped groove, and the locking piece and the pedicle screw are connected by thread.

As a further technical solution, the second thread includes a cortical bone thread and a double thread that are adjacently arranged in sequence.

As a further technical solution, the end of the locking piece is provided with an inner cavity.

The above-mentioned beneficial effects of the present invention are as follows:

(1) In the present invention, the first connecting rod and the second connecting rod are rotated and connected to realize the adjustment of the coronal plane angle; the second connecting rod and the third connecting rod are inserted and moved to realize the length adjustment; the third connecting rod and the vertebral plate The hook is rotated and connected to realize the adjustment of the vertical angle of the coronal plane, so that three controllable functional adjustments of the coronal plane angle adjustment, length adjustment and coronal plane vertical angle adjustment can be achieved. The adjustment of the coronal plane angle during the operation ensures the accuracy of the laminar hook. Hook on the lower edge of the vertebral plate; through the adjustment of the vertical angle of the coronal plane, the angle of the hook of the lamina can be adjusted to make it fit accurately with the lamina, and it is not easy to move; through the adjustment of the length, the vertebral body can be compressed and tightened without replacing the connecting rod Or laminar hook, suitable for all kinds of lumbar spondylolysis patients' vertebrae, to meet the differences in the patient's vertebrae shape.

(2) The connecting rod assembly of the present invention has an adjustable function through the form of rotating connection and plug-in mobile connection, without pre-bending the connecting rod, ensuring the regularity of the structure, and the connecting rod assembly is simple in structure and does not occupy the surgical space position , to ensure adequate bone grafting.

(3) The present invention uses the pedicle screw and the lamina hook to fix the vertebral body, and realizes the effective pressure on the isthmus by adjusting the connecting rod assembly, so as to ensure a stable fusion environment for the bone graft, which is beneficial to the fusion of the bone graft.

(4) The present invention can effectively fix the isthmus of lumbar spondylolisthesis through the adjustment of the connecting rod assembly, which conforms to the physiological and anatomical structure, and can ensure that the pedicle screw, the connecting rod assembly and the connecting parts of the lamina hook are in the same force plane, and the biological The mechanical advantage is obvious, and the surgical trauma of the device is small, it will not affect the adjacent vertebral bodies and intervertebral discs, maintain the normal activity of the spine, and will not damage the ligaments, nerves and other tissues, and avoid postoperative complications.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

1 is a schematic three-dimensional structural diagram of an entire adjustable laminar hook internal fixation device for lumbar spondylosis according to one or more embodiments of the present invention;

2 is a schematic front view of an adjustable laminar hook internal fixation device for lumbar spondylolysis according to one or more embodiments of the present invention;

3 is a schematic top view of an adjustable laminar hook internal fixation device for lumbar spondylolysis according to one or more embodiments of the present invention;

4 is a schematic diagram of any three-dimensional structure of an adjustable laminar hook internal fixation device for lumbar spondylosis according to one or more embodiments of the present invention in a use state;

5 is a schematic perspective view of a coronal plane angle adjustment component according to one or more embodiments of the present invention;

6 is a schematic perspective view of a length adjustment member according to one or more embodiments of the present invention;

7 is a schematic perspective view of a coronal plane vertical angle adjustment component according to one or more embodiments of the present invention;

8 is an exploded perspective structural diagram of the connecting rod assembly and the lamina hook according to one or more embodiments of the present invention;

9 is a schematic perspective view of a first nut according to one or more embodiments of the present invention;

10 is a schematic three-dimensional structural diagram of a pedicle screw according to one or more embodiments of the present invention;

11 is a schematic perspective view of the second nut according to one or more embodiments of the present invention;

FIG. 12 is a schematic three-dimensional structure diagram of a first bolt according to one or more embodiments of the present invention;

13 is a schematic perspective view of a third nut according to one or more embodiments of the present invention;

14 is a schematic perspective view of a locking ring according to one or more embodiments of the present invention;

In the figure: the distance or size between each other is exaggerated in order to show the position of each part, the schematic diagram is for illustration only;

Among them, 1. pedicle screw; 2. first nut; 3. first connecting rod; 4. first bolt; 5. second nut; 6. second connecting rod; 7. locking ring; 8. , the third nut; 9, the third connecting rod; 10, the second bolt; 11, the fourth nut; 12, the lamina hook; 13, the inner cavity; 14, the first thread; 15, the second thread; 16 , the third thread; 17, U-shaped groove; 18, the first double-bolt slot; 19, the first single-bolt slot; 20, the slot; 21, the serrated rod; 22, the second double-bolt slot; 23 , the second single bolt slot; 24, the lamina hook part; 25, the bolt head; 26, the fourth thread; 27, the fifth thread; 28, the sixth thread; 29, the seventh thread;

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

As described in the background art, the existing laminar hook internal fixation devices cannot adapt to the differences in the spinal structure of different patients, and cannot meet the needs of different individuals; most laminar hooks have connecting heads, occupying a large space, and the opening angle of the laminar hooks is large. In order to solve the above technical problems, the present invention proposes an adjustable laminar hook internal fixation device for lumbar spondylolysis. .

In a typical embodiment of the present invention, as shown in FIGS. 1 to 14, an adjustable laminar hook internal fixation device for lumbar spondylolysis is proposed, including a pedicle screw 1, a connecting rod assembly, and The lamina hook 12, wherein the two ends of the connecting rod assembly are respectively connected with the pedicle screw 1 and the lamina hook 12.

The connecting rod assembly is composed of a first connecting rod 3, a second connecting rod 6 and a third connecting rod 9. The first connecting rod 3, the second connecting rod 6 and the third connecting rod 9 are connected in sequence, wherein the first connecting rod 3 It is fixedly connected with the pedicle screw 1, the first connecting rod and the second connecting rod are rotatably connected, the third connecting rod 9 is rotatably connected with the lamina hook 12, and the rotation plane where the first connecting rod and the second connecting rod are located is connected with the third connecting rod. The rotating planes where the connecting rod and the lamina hook are located are perpendicular to each other; the functional parts are divided into three parts according to the functional positioning: the coronal plane angle adjustment part, the length adjustment part, and the coronal plane vertical angle adjustment part.

Specifically, as shown in Figure 5, Figure 8, Figure 11, Figure 12, the coronal plane angle adjustment component is composed of a first connecting rod 3 and a second connecting rod 6, and the first connecting rod 3 and the second connecting rod 6 are connected One end is a double-ear raised structure, the double-ear raised structure is provided with a first double-bolt slot 18, and the other end of the first connecting rod 3 is a cylindrical structure.

One end of the second connecting rod 6 connected to the first connecting rod 3 is a single-ear raised structure, the other end of the second connecting rod 6 is a hollow cylindrical structure, and the single-ear raised structure is provided with a first single-bolt slot hole 19. When the first connecting rod 3 and the second connecting rod 6 are connected, the single-ear protrusion structure of the second connecting rod 6 extends into the double-ear protrusion structure of the first connecting rod 3, so that the first single-bolt slot hole is 19 is concentric with the first double-bolt slot 18, and the first bolt 4 passes through the first single-bolt slot 19 and the first double-bolt slot 18, and is fixed by the second nut 5, wherein the second nut 5 has a fifth thread 27, and the screw rod of the first bolt 4 has a fourth thread 26, and the engagement connection between the second nut 5 and the first bolt 4 is realized through the cooperation of the fourth thread 26 and the fifth thread 27.

When it is necessary to adjust the coronal plane angle, it is necessary to use a wrench to fix the bolt head 25 on the first bolt 4, loosen the second nut 5, and adjust the angle between the first connecting rod 3 and the second connecting rod 6, and then Drive the lamina hook 12 to move to adjust the angle of the lamina hook 12, so as to realize the adjustment of the coronal plane angle and ensure that the lamina hook is accurately hooked on the lower edge of the lamina. Tighten the second nut 5 to fix the second connecting rod 6 .

As shown in Fig. 6, Fig. 8, Fig. 13, Fig. 14, the length adjusting part is composed of a second connecting rod 6 and a third connecting rod 9, and the end connecting the second connecting rod 6 and the third connecting rod 9 is a hollow cylindrical shape The upper part of the side wall of the second connecting rod 6 is provided with a slot 20, the inside of the second connecting rod 6 is provided with a locking ring 7, and the end connecting the third connecting rod and the second connecting rod 6 is a serrated rod 21 structure.

The locking ring 7 is composed of a screw rod and a circular ring. The screw rod is provided with a seventh thread 29, and the inner surface of the circular ring is provided with serrations 30 along its circumference. Inside the second connecting rod 6, the screw structure of the locking ring 7 protrudes from the slot 20 on the upper part of the side wall of the second connecting rod 6 and is connected with the third nut 8, which has a seventh thread 29 to match the sixth thread 28.

When the second connecting rod 6 is connected with the third connecting rod 9, first loosen the third nut 8 to lower the locking ring 7 to a proper position, and then extend the serrated rod 21 on the third connecting rod 9 into the second connecting rod The inside of the rod 6 passes through the ring structure of the locking ring 7, and the serrated rod 21 is engaged with the sawtooth 30 of the locking ring 7. After the length is determined, the third nut 8 is tightened to make the locking ring 7 rise so as to Fixing the third connecting rod 9, the main function of the sawtooth 30 and the sawtooth rod 21 is to increase the frictional force, and through the adjustment of the length, it is ensured that the vertebral body is compressed and tightened, and there is no need to replace the connecting rod or the lamina hook.

As shown in Figure 7, Figure 8, Figure 11, Figure 12, the coronal plane vertical angle adjustment component is composed of a third connecting rod 9 and a lamina hook 12, and one end of the third connecting rod 9 connected to the lamina hook 12 is a double ear A raised structure, the double-ear raised structure is provided with a second double-bolt slot 22, the lamina hook 12 is a hook-like structure, and the end of the lamina hook connected to the third connecting rod 9 is provided with a second single-bolt slot hole twenty three.

When connecting, one end of the lamina hook 12 extends into the double-ear protrusion structure on the third connecting rod 9, so that the second double-bolt slot 22 is concentric with the second single-bolt slot 23, and the second bolt 10 passes through the second double-bolt slot 22 and the second single-bolt slot 23, and is fixed by the fourth nut 11, wherein the fourth nut 11, the second bolt 10 and the second nut 5, the first The structure of the bolt 4 is the same, that is, the fourth nut 11 has a fifth thread, and the screw of the second bolt 10 has a fourth thread. mesh.

When adjusting the vertical angle of the coronal plane, loosen the fourth nut 11, adjust the angle of the lamina hook 12, hook the lamina hook part 24 on the lower edge of the lamina of the isthmic vertebral body, and make the lamina hook 12 connect with the lamina. To fit accurately and not easily move, tighten the fourth nut 11 to fix the lamina hook 12 .

The coronal angle adjustment component, the length adjustment component and the coronal vertical angle adjustment component work together to ensure that the adjustable laminar hook internal fixation device can accurately and reliably fix the isthmus of lumbar spondylolisthesis, and the connecting rods of the connecting rod assembly The structures are all in the same coronal plane, and the adjustment of the adjustable laminar hook internal fixation device is also in the coronal plane and the vertical coronal plane, which effectively ensures the force balance of the adjustable laminar hook internal fixation device. Some functional components adjust the internal fixation device to achieve perfect fixation of the lamina hook 12 .

It is understandable that there is no strict sequence in the use and adjustment of the three-part functional components. It is decided according to the actual situation of the clinical operation and the doctor's willingness to operate. Everything is based on the effective implementation of the adjustable laminar hook internal fixation device. Too restrictive.

As shown in FIGS. 1 , 9 and 10 , the tail of the pedicle screw 1 has a U-shaped groove 17 structure, which can be matched with the cylindrical structure of the first connecting rod 3 in the connecting rod assembly. The inner wall of the U-shaped groove 17 is provided with a third thread 16, the first nut 2 has a first thread 14, and the first thread 14 is engaged with the third thread 16, thereby fixing the first nut 2 on the vertebral arch. On the U-shaped groove 17 at the tail of the screw 1.

Specifically, when the pedicle screw 1 is fixedly connected with the first connecting rod 3, the cylindrical structure of the first connecting rod 3 is inserted into the U-shaped groove 17 on the pedicle screw 1, and the first nut 2 is used for fastening. Pressed and fixed, the first nut 2 also has an inner cavity 13, and the setting of the inner cavity 13 can be matched with an inner angle wrench, so as to facilitate the disassembly and installation of the first nut 2. The inner cavity can be set in a hexagonal form, and it can be easily disassembled and installed with an Allen key.

Among them, the specifications and dimensions of the pedicle screw 1 are strictly in accordance with the medical device standards. The pedicle screw 1 is provided with a second thread 15, and the design of the second thread 15 conforms to the physiological characteristics of the spine; the second thread 15 includes two parts, the upper part of which is the cortex Bone thread, the lower part is double thread, which can increase the holding force and shorten the nail placement time.

Through the adjustment function of the connecting rod assembly, the pedicle screw, connecting rod assembly and the connecting parts of the lamina hook can be guaranteed to be in the same force plane, which has obvious biomechanical advantages, and the device has little surgical trauma and will not cause any damage to the adjacent vertebral bodies and intervertebral discs. It will not damage the ligaments, nerves and other tissues, and avoid postoperative complications.

It can be understood that the bolts described in this embodiment can adopt a hexagonal bolt structure, and the nut can adopt a hexagonal nut structure. In other embodiments, other types of bolts and nuts can also be used, which is not limited here.

The application method of the adjustable laminar hook internal fixation device for lumbar spondylolysis is as follows:

When performing surgery on patients with lumbar spondylolisthesis, the position of the fractured vertebral body of the patient should be exposed first to reveal the surgical area. Lumbar spondylolisthesis can be divided into unilateral rupture and bilateral rupture. Fixed bilaterally. The first is to determine the position of the screw, usually the midline of the transverse process and the posterolateral confluence of the superior articular process are selected, or the point of screw placement can be determined according to the method of the vertices of the herringbone ridge, and the pedicle screw 1 is inserted, and the second thread 15 conforms to the Physiological properties of the spine. Autologous or allogeneic bone is implanted in the fractured isthmus after clearing the surgical area.

The head of the pedicle screw 1 is provided with a U-shaped groove 17, which can be matched with the cylindrical structure of the first connecting rod 3 in the connecting rod assembly. After the first connecting rod 3 is inserted, the first nut 2 is used for pressure fixing, the first thread 14 can be matched with the third thread 16 in the U-shaped groove 17, and the upper end of the first nut 2 is provided with an inner cavity 13. It can be tightened with an internal angle wrench, so as to fix the first connecting rod 3 on the pedicle screw 1.

The first single-bolt slot 19 on the second connecting rod 6 can be matched with the first double-bolt slot 18 on the first connecting rod 3 to be connected by the first bolt 4 .

When adjusting the coronal plane angle, use a wrench to fix the bolt head 25 on the first bolt 4, loosen the second nut 5 first, and adjust the angle of the connecting rod assembly and the lamina hook 12 until the lamina hook 12 is located in the lamina. When the lower edge is in a proper fixing position, tighten the second nut 5 to fix the second connecting rod 6 .

The screw of the locking ring 7 is provided with a seventh thread 29 , which can be matched with the sixth thread 28 in the third nut 8 . The locking ring 7 is lowered to a proper position by loosening the third nut 8 to ensure that the length of the third connecting rod 9 can be adjusted normally in the hollow cylindrical second connecting rod 6 . The second double-bolt slot 22 on the third connecting rod 9 can be matched with the second single-bolt slot 23 on the vertebral plate hook 12 , and is connected by the second bolt 10 .

When adjusting the vertical angle of the coronal plane, first loosen the fourth nut 11, adjust the angle of the lamina hook 12, hook the lamina hook 24 on the lower edge of the vertebral body lamina of the isthmic fissure, and ensure that the lamina hook 24 It can fit well with the vertebral plate, and tighten the fourth nut 11 to fix the angle of the vertebral plate hook 12 .

After the coronal plane angle adjustment and the coronal plane vertical angle adjustment are completed, the lamina hook 12 has been accurately hooked on the lower edge of the lamina. The inner ring of the locking ring 7 is provided with serrations 30 which can engage with the serration rods 21 on the third connecting rod 9 .

First, loosen the third nut 8 to lower the locking ring 7 . At this time, the locking ring 7 has no contact with the serrated rod 21 or the contact friction is reduced, and the length of the third connecting rod 9 can be adjusted in the second connecting rod 6 . Then use an auxiliary tool to pressurize the vertebral body and the fractured isthmus, press the isthmus bone graft, press the lamina hook 12, the serrated rod 21 on the third connecting rod 9 has been inserted into the locking ring 7, and the lamina hook The hook portion 24 has been pressed against the lower edge of the lamina and fits well. Finally, the third nut 8 is tightened to make the locking ring 7 rise, and the frictional force between the locking ring 7 and the serrated rod 21 increases, so that the third connecting rod 9 is fixed.

It can be understood that there is no restriction on the operation sequence of the functional components during adjustment, and necessary adjustments can be made according to the actual situation of the operation and the doctor's operation willingness. After the fractured vertebral body is placed in the pedicle screw 1 and bone grafting, the first connecting rod 3 is connected and fixed with the pedicle screw 1, and the coronal plane angle is adjusted first, and the angle of the connecting rod assembly and the lamina hook 12 is preliminarily determined; then Adjust the length, use an auxiliary tool to pressurize the vertebral body, adjust the length of the connecting rod assembly through the locking ring 7; finally adjust the vertical angle of the coronal plane, hook the hook portion 24 of the vertebral plate on the lower edge of the vertebral plate, and complete the adjustment Internal fixation of lumbar spondylolisthesis with laminar hook internal fixation device.

The device has the advantages of simple operation and structure, convenient adjustment, stability and reliability, easy installation and operation, and multiple adjustment functions. To ensure patient recovery, it has broad application prospects.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. An adjustable vertebral lamina hook internal fixation device for lumbar isthmus fissure is characterized by comprising a vertebral pedicle screw, wherein the vertebral pedicle screw is connected with a vertebral lamina hook through a connecting rod component; the connective bar subassembly include with pedicle of vertebral arch screw fixed connection's first connective bar, first connective bar and second connective bar rotate to be connected, and the second connective bar has hollow structure to penetrate wherein for the third connective bar, and second connective bar axial displacement can be followed to the third connective bar, and third connective bar and vertebral lamina hook rotate to be connected.

2. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 1, wherein the rotation plane of the first connecting rod and the second connecting rod is perpendicular to the rotation plane of the third connecting rod and the laminar hook.

3. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 1, wherein a locking ring is provided in the hollow structure of the second connecting rod, and the locking ring is sleeved on the third connecting rod.

4. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 3, wherein the locking ring is provided with saw teeth on the inner side, the third connecting rod is provided with a saw-tooth rod, the saw-tooth rod penetrates into the hollow structure and the locking ring, and the saw teeth of the saw-tooth rod and the locking ring are engaged.

5. The adjustable laminar hook internal fixation device according to claim 3, wherein a screw is fixedly arranged on the side of the locking ring, a slot is formed on the side wall of the second connecting rod, and the screw passes through the slot and is fixedly connected with a fastener.

6. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 1, wherein the pedicle screw has a U-shaped recess at the tail for the first connecting rod to pass through.

7. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 6, wherein the pedicle screw is fixedly connected with the locking member at the U-shaped groove.

8. The adjustable laminar hook internal fixation device for lumbar isthmus fissure of claim 7, wherein the locking member is provided with a first thread on the outer side, the pedicle screw head is provided with a second thread, the inner wall of the U-shaped groove is provided with a third thread, and the locking member and the pedicle screw are connected by the threads.

9. The adjustable laminar hook internal fixation device for lumbar isthmus fissures as claimed in claim 8, wherein said second thread comprises a cortical bone thread and a double thread disposed adjacent in series.

10. The adjustable laminar hook internal fixation device for lumbar isthmus fissures as claimed in claim 7, wherein said retaining member has an internal cavity at its end.

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