Marcus D Sanders

US Patent:

58999027, May 4, 1999

Filed:

Jul 3, 1997

Appl. No.:

8/887832

Inventors:

Henry John Harding Brown - Solon OH
John Mark Kapitan - Shaker Hts. OH
Gerald Kotnik - Perry OH
Marcus Maria Sanders - Cleveland OH

Assignee:

DePuy Motech AcroMed Corporation - Cleveland OH

International Classification:

A61B 1770

US Classification:

606 61

Abstract:

An improved fastener is provided for use in retaining vertebrae in a desired spatial relationship. The fastener has a mounting section with a first external thread to engage a vertebra. The fastener has a retaining section with a second external thread to engage an internal thread on a retaining element, such as a nut. A pair of parallel flats are formed on opposite sides of the retaining section. The flats are spaced apart by a distance which is substantially the same as or greater than a root diameter of the external thread on the retaining section. A driving recess in an axially outer end of the retaining section has arcuate corner portions which receive force to effect rotation of the fastener relative to a vertebra engaged by the mounting section. The arcuate corner portions of the driving recess are offset from a plane containing the longitudinal central axis of the retaining section and extending perpendicular to the flats.