Bone screw with improved threads
US5226766A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 21, 1992 |
| Grant date | Jul 13, 1993 |
| Priority date | — |
| Expiry date | May 21, 2012 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B17/863
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A bone screw having a helical thread that gradually increases in thickness from the tip to the head of the screw. The thin thread at the tip of the screw can be inserted into a bone with minimal tearing or cracking of the bone. The thicker treads ascending from the tip to the head of the screw displaces bone against the superior (top) thread surfaces. This displacement of bone increases the screw's resistance to being pulled-out of the bone. The thicker core just below the screw head increases the screw's ability to withstand compressive and distractive loads. The core is thickest just below the head because it is at that point on the screw that the fulcrum loads are greatest.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.