Lumbar spondylolysis restoration internal fixation system

Abstract

The invention relates to a lumbar spondylolysis restoration internal fixation system, comprising a pedicle screw implanted into pedicle and a vertebral plate hook hooking the lower edge of a vertebral plate; the pedicle screw is connected with the vertebral plate hook by a cylindrical connecting rod; the head part of the pedicle screw is provided with a U-type groove; the connecting rod can be arranged in the U-type groove in a sliding manner; the top part of the U-type groove is provided with internal threads; the U-type groove is connected with a plug screw which is used for fixing the connecting rod; the vertebral plate hook is fixedly connected to the connecting rod by a locking plate; the vertebral plate hook is positioned at the end, which is far from the pedicle screw, of the connecting rod; the locking plate is an expanded part at the tail end of the connecting rod; the vertebral plate hook, the locking plate and the connecting rod are integrated to form a repository; and the locking plate is fixed on the vertebral plate by locking screws and is provided with locking holes matched with the locking screws. The invention has the advantages of elimination of tender moving of the vertebral plate after operation, high positioning precision of screws, simple and convenient operation, reservation of lumbar motion segment and high fusion rate of fracture end after operation.

Description

technical field [0001] The invention relates to a reduction and internal fixation system for lumbar spondylolisthesis. technical background [0002] Lumbar spondylolysis, also known as nonunion of isthmus, spondylolysis, developmental factors and repeated stress are the most common causes, and it is also one of the common causes of low back pain. The severity of symptoms and signs depends on the age, type of nonunion of the isthmus, instability of the spine, whether it is combined with spondylolisthesis and its degree, etc. [0003] Patients with lumbar spondylolysis are relatively common, and about 10% to 20% of patients need surgical treatment after standard non-surgical treatment fails. Intervertebral fusion is the most common method of dealing with these patients. However, the patient will lose too many motion segments and motor function in this way. [0004] In 1968, Kimura et al. first proposed the method of plaster bed fixation after simple isthmus or facet defect ...

AI Technical Summary

Problems solved by technology

However, because the screw directly passes through the isthmus, the amount of bone graft that can be accommodated by the slender isthmus is significantly reduced, which affects the fusion of bone graft; moreover, the development of lumbar vertebrae with isthmus is often abnormal, and the isthmus is narrow and long, so the screw sometimes cannot pass through. Or through the lamina into the spinal canal, resulting in cauda equina or nerve root damage; and the accuracy of screw positioning is high, the operation is difficult, and the failure rate of the operation is high

[0006] 2. Steel wire binding method (Scott method), which needs to expose the transverse process and pass through the steel wire. The surgical trauma is large, the operation is complicated, the bleeding is frequent, and there is a risk of nerve root damage. In addition, the anterior cortex of the L5 transverse process slopes forward and downward, and the transverse process The lower space is narrow, and it is extremely difficult to thread and wrap the steel wire; moreover, to expose the transverse process of L5, it is necessary to cut the iliolumbar ligament, which will aggravate the instability of L5

[0008] However, this fixation method still has the following disadvantages:

In the hook screw fixation method, a connector is required between the pedicle screw and the connecting rod, and between the lamina hook and the connecting rod; since the distance between the lamina and the pedicle is extremely short, the operation is extremely inconvenient ; and even if the two connectors can be successfully installed, most of the space has been occupied, and there is not enough bone graft bed between the pedicle, isthmus, and lamina, which will easily lead to the final failure of the operation

[0011] 3) The lamina hook only serves to limit the downward and backward sliding of the lamina, not a "three-dimensional stability" system

[0012] 4) The lamina hook tightens the lamina and needs to bear the pressure caused by the spinal movement, resulting in a wide and thick lamina hook, which is likely to cause iatrogenic lumbar spinal stenosis

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