Self-deploying locking screw retention device

摘要

A screw assembly and a spinal implant. The screw assembly includes a screw with a head and a shaft where a screw retention member is positioned beneath the head of the screw and substantially surrounds the shaft of the screw. The screw retention member is formed from a temperature-sensitive material. The screw retention member has a first contracted position adapted for inserting the screw through at least one hole in the spinal implant and a second expanded position adapted for retaining the screw within the at least one hole in the spinal implant. The screw retention member may be in the form of a coiled spring or a collar having a plurality of tabs.

主权项

1. A screw assembly for retaining a screw in a hole in a spinal implant, comprising a screw comprising a head and a shaft, and a self-deploying screw retention member positioned beneath the head of the screw and surrounding the shaft of the screw, wherein the screw retention member comprises a thermal-reactive shape memory metal, and the screw retention member is maintained at a contracted position at a temperature below room temperature, which contracted position is adapted to permit insertion of the screw assembly through a hole in a spinal implant, and expands into an expanded position when the screw retention member attains a transformation temperature of from about 30° C. to about 37° C., which expanded position is adapted for retaining the screw assembly within the hole in the spinal implant.