Multi-axial bone screw assembly
US5797911A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1996 |
| Grant date | Aug 25, 1998 |
| Priority date | — |
| Expiry date | Sep 24, 2016 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2090/037
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A multi-axial bone screw assembly includes a bone screw having a partially spherical head. The bone screw head is truncated at an upper surface in which a tool receiving recess is defined. The assembly includes a receiver member including a central bore that defines a tapered recess to receive the head of the bone screw. The bore of the receiver member also defines a channel communicating with the recess and configured to receive a spinal rod therein. A portion of the channel is threaded to receive a set screw above the rod. The assembly also includes a crown member disposed between the rod and the head of the bone screw. As the set screw is tightened into the receiver member, the set screw compresses the rod against the crown member, which presses the head of the bone screw into the tapered recess. In one embodiment, the head of the bone screw includes a flared edge that penetrates at least the crown member as the assembly is tightened.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.