TORQUE DRIVERS FOR HEADLESS THREADED COMPRESSION FASTENERS

摘要

A threaded-shaft or fastener such as a headless bone screw, intramedullary support or the like, has a tool-receiving structure on the axial end of an externally threaded proximal end for application of torque directly to the fastener. A cannulated cap nut with internal threads complementary to the thread on the shaft can be jammed on the shaft in a tightening direction, allowing driving torque to be applied to the shaft through the cap nut for driving the fastener into a work material such as bone tissue. When the fastener has been driven to bring the cap nut up to the work material, torque is applied between tools in the fastener and cap nut, and then to the fastener alone, unjamming and advancing the fastener such that the proximal end of the fastener can be embedded in the bone tissue. The fastener is advantageously a headless bone compression screw.

主权项

1. In combination, a threaded surgical fastener, a cannulated cap nut and at least one tool for applying driving torque,
wherein the surgical fastener comprises a shaft to be embedded in tissue at least along an axial part of an externally threaded proximal end of the surgical fastener, and the proximal end has an axially facing non-round fitting for receiving a fastener wrench for applying said driving torque directly to the surgical fastener; wherein the cannulated cap nut is configured for application of torque to the cap nut, and an axial opening sized to admit the fastener wrench, the cap nut being internally threaded along a distal axial distance limited proximally by a thread stoppage, such that the cap nut threadably engages the proximal end of the surgical fastener up to the thread stoppage, whereby threading the fastener into the cap nut up to the thread stoppage enables application of torque to the fastener via application of torque to the cap nut, and application of torque to the fastener relative to the cap nut, via the fastener wrench in the axially facing fitting, enables the fastener to advance from the cap nut into the tissue.