Medical vertebral arch pedicle renovating screw assembly

Abstract

The invention discloses a medical vertebral arch pedicle renovating screw assembly which comprises a screw sheath and a screw which are mutually matched, wherein the screw sheath has certain mechanical strength and toughness, and the medical absorbable material can effectively maintain the mechanical strength for 2 to 3 months in vivo; the screw sheath is divided into a head end and a sheath body;the head end is a cone with a sealed front end, and the sheath body is a cylinder; external threads are arranged on the outer surface of the cylinder, and a longitudinally extended triangular prism-shaped cavity is arranged in the cylinder; the cylinder is divided into three side walls by the cavity, and internal threads are designed on the inner wall of the cavity; the screw is made of medical titanium alloy and comprises a thread section and a tail part; the thread section is formed by connecting a screw tip and a screw body, and both the screw tip and the screw body are in external threaddesign; the tail part is provided with a radially communicated U-shaped groove, and internal threads are arranged on the inner wall of the U-shaped groove. The invention can improve the internal fixation stability and reliability of the spinal column in a renovating operation or the secondary screw arranging process, reduce the occurring rate of vertebral arch pedicle screw loosening and even separation and lower the failure rate of operations.

Description

technical field [0001] The invention belongs to medical auxiliary equipment, and relates to pedicle screws used in spinal internal fixation, in particular to a medical pedicle revision screw assembly, which is mainly used to improve the stability of internal fixation during revision surgery or secondary screw placement during surgery and reduce the risk of internal fixation failure. Background technique [0002] At present, transpedicular internal fixation has become a routine technique in spinal surgery. Pedicle screws can be used for three-dimensional correction of spinal deformity and reconstruction of spinal stability by means of traction, compression, and rotation. The key to the stability of pedicle screw fixation depends on whether sufficient "bone-screw" interface holding force can be obtained, and this holding force should be maintained until solid bony fusion between vertebral bodies is achieved. However, in clinical work, osteoporosis often leads to a decrease i...

AI Technical Summary

Problems solved by technology

[0004] 1. After the bone cement is perfused, the bone cement material and the screw are tightly bonded, and it is extremely difficult to remove the cured screw, causing damage to the surrounding tissue;

[0005] 2. Bone cement is difficult to degrade in the body, and a secondary interface of "screw-bone cement-bone" will be formed. It is difficult to achieve bony healing between nails and bones, and cannot maintain long-term stability in the body. There are great limitations in clinical application. Security risks;

[0006] 3. More importantly, injecting material into the screw channel and the surrounding bone through various methods is likely to cause leakage, space-occupying lesions, and serious complications

Even if absorbable materials are used, and the dose and pressure of injected materials are carefully controlled during the operation, the occurrence of leakage cannot be completely avoided, which brings great challenges to the operation of the surgeon and largely limits the clinical application. widely cited

[0007] In terms of improved screw design, increasing the screw diameter may lead to the risk of pedicle fracture, and increasing the screw length may damage the anterior column of the vertebral body, which may cause visceral and vascular injuries

Although the currently used expandable pedicle screws can significantly improve the stability of internal fixation during revision surgery or secondary screw placement during surgery, the screws are in a state of expansion in the body for a long time, resulting in plastic deformation, and at the same time, the new bone continues to grow. In the process of screw removal, the expansion part of the front end of the screw cannot be retracted even after the inner plug is pulled out, which brings great difficulties to the removal of the screw. If it is forcibly removed, it will cause a large range of bone destruction. , seriously affecting the stability of the spine

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