Patent ID: 8512383
Filing Date: 2013-08-20
Classification: A61B

Abstract:
1. A method of attaching an extension to a bone anchor for use in percutaneous spinal surgery, comprising the steps of: providing a bone anchor including a first portion for attachment to a vertebra and a second portion for attachment to a connecting element, the bone anchor including an exterior surface and an interior surface and an extension coupling surface disposed on said interior surface; providing an elongate hollow extension including an elongate hollow outer sleeve having a distal end and a proximal end and an elongate hollow inner sleeve disposed within said outer sleeve and having a distal end and a proximal end, said outer sleeve and said inner sleeve being movable rotationally relative to each other, an anchor engaging member being disposed on said inner sleeve and projecting radially outwardly therefrom, the outer sleeve being configured to be fixedly held on the bone anchor adjacent the exterior surface thereof; attaching said extension to said bone anchor by rotating said inner sleeve relative to said bone anchor such that said projecting anchor engaging member rotatably engages said extension coupling surface on the interior surface of said bone anchor; providing a securement member defined by cooperative surfaces adjacent the distal end of said inner sleeve and said outer sleeve operable upon relative rotation of said inner sleeve and said outer sleeve to radially secure said inner sleeve and said outer sleeve together and to maintain engagement of said anchor engaging member and said anchor, the cooperative surface of said securement member on said inner sleeve including a flange extending radially outwardly from said inner sleeve and the cooperative surface of said securement member on said outer sleeve being defined by a groove extending into an inner surface of said outer sleeve; and securing said inner sleeve and said outer sleeve radially together by rotating the flange on said inner sleeve into the groove in said outer sleeve.