A screw-rod instrument specially used for posterior atlantoaxial vertebrae fixation

Abstract

The invention discloses a screw-rod instrument specially used for posterior atlantoaxial vertebrae fixation, comprising two pulling-screws (2), two supporting-screws (1), two variable cross section fixing rods (3), two lock nuts (4) and a bracing beam (5). Each of the variable cross section fixing rods (3) is configured to connect a supporting-screw (1) and a pulling-screw (2), the bracing beam (5) is configured to connect both of the variable cross section fixing rods (3); wherein each of the supporting-screws (1) comprises a first tail (11) and a first head (12), and each of the pulling-screws (2) comprises a second tail (21) and a second head (22); both the first tail (11) and the second tail (21) are provided with nail grooves, with U-shaped grooves on the sides; wherein each of the nail grooves is provided with internal thread inside, and the lock nut (4) is connected with the nail groove; each of the variable cross section fixing rods (3) passes through the U-shaped grooves and is fastened by the lock nut (4); the bottoms of the nail grooves of the supporting-screws (1) are 2-6 mm higher than the bottoms of the nail grooves of the pulling-screws (2). The aforementioned screw-rod instrument not only increases the safety and convenience of a surgery, but also improves the function of spondylolisthesis reduction of the screw-rod system through raising the bottoms of the nail grooves 2-6 mm higher.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The invention relates to a technical field of medical apparatus and instruments, and more specifically to a screw-rod instrument specially used for posterior atlantoaxial vertebrae fixation.DESCRIPTION OF THE RELATED ART[0002]The posterior atlantoaxial transarticular screw (Magerl screw) fixation technique has been successfully developed since 1979, it was always considered as the golden standard of a surgery of atlantoaxial fixation. However, with the advent of the posterior atlantal lateral mass screw technique (Goel-Harms technique), the posterior short-segment screws and rods fixation technique composed of atlas screw combined with axis screw gradually replaces Magerl screw, and becomes a preferred method for the posterior atlantoaxial fixation, regarded as the new golden standard of the surgery. The posterior short-segment screws and rods fixation technique separately arranges screws in the atlas and the axis, it not only has advantages inc...

AI Technical Summary

Benefits of technology

The present invention provides a screw-rod instrument for posterior atlantoaxial vertebrae fixation that increases the range of application and simplifies surgical operation. The instrument includes two pulling-screws, two supporting-screws, two variable cross section fixing rods, two lock nuts, and a bracing beam. The instrument is designed to adapt to the atlantoaxial structure and improve the function of reduction. The bottom of the nail grooves of the supporting-screws is higher than the bottom of the nail grooves of the pulling-screws, which increases the lifting distance for spondylolisthesis reduction without adjusting other structures. The fixing rod is also designed to prevent rotation, which makes the operation easier and safer.

Problems solved by technology

However, the operation is difficult, and it is not easy to fix, and the misoperation is likely to cause damage to the patient.

Especially under the circumstance of bending the fixing rod, rotation is easy to happen, resulting in high difficulty to fix and complication to operate.

However, the existing screws for cervical posterior instrument are polyaxial screws with short arms, thus configuration and operation of rods are very difficult, especially for the clinical cases in serious dislocation of the atlas and the axis, a doctor always needs to carry out auxiliary operation by using a device for lifting the screw and pressing the rod in a narrow space.

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