Modular polyaxial locking pedicle screw
US5725528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1997 |
| Grant date | Mar 10, 1998 |
| Priority date | — |
| Expiry date | Feb 12, 2017 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B17/7035
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A modular polyaxial pedicle screw and orthopaedic rod implant device including same includes a shaft portion, a cuff, a stem portion, and a rod coupling sub-assembly. The shaft portion is designed to be inserted into the pedicle, has a hemispherical upper portion, and includes a second threading formed on the exterior surface adjacent to the hemispherical protuberance. The stem portion is a threaded post having an enlarged lower socket portion which includes a spherical recess formed at the base thereof, the recess being ideally suited to polyaxially rotate on the hemispherical upper portion of the shaft. The cuff is a cylindrical element designed to seat around the interface of the hemispherical portion of the shaft and the lower socket portion of the stem, initially so that the stem and shaft may polyaxially rotate relative to one another, and subsequently to hold the stem and shaft in final securement. The rod coupling sub-assembly consists of a rod coupling element which is mountable on the post portion of the stem, and a top locking nut which secures the rod coupling element to the post between the nut and the cuff. Spacer elements may be utilized which are positioned on the p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.