Multi-axial bone screw assembly

US6280442A · kind A · utility

Assignee

• SDGI, LLC · US

Inventors

• B. Thomas Barker · Memphis, US
• John Stewart Young · Scottsdale, US
• Craig Squires · Cordova, US
• David L. Brumfield · Collierville, US
• Chris E. Johnson · Germantown, US
• Dennis J. Buchanan · Memphis, US

Key dates

• Filing date: Sep 1, 1999
• Grant date: Aug 28, 2001
• Expiry date: Sep 1, 2019

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B2090/037
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A bottom-loading multi-axial bone anchor apparatus is disclosed. The apparatus includes a receiver member, a crown member, a bone anchor and a retaining member. The receiver member defines an upper opening and a lower opening, which may form part of the same opening, a channel, and a groove. The crown member and bone anchor are loaded into the lower opening of the receiver member, and the retaining member fits around the bone anchor and into the groove in the receiver member. The bone anchor is capable of multi-axial positioning with respect to the receiver member. An elongated member is placed in the channel of the receiver member, contacting the crown member, and a compression member is applied via the upper opening. The compression member presses down on the elongated member, which presses down on the crown member and locks the bone anchor between the crown member and the retaining member.