05989291 is referenced by 294 patents and cites 6 patents.

An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is a belleville washer. In a first embodiment there are two belleville washers which are oriented in opposite directions such that the narrow ends thereof are in contact with each other and the wider ends are in contact with the respective end plates. In a second embodiment there is a single belleville washer which is modified to mount onto a ball-shaped head. The lower plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The modified belleville washer is lockably mounted to the head such that the wider portion of the washer seats against the upper plate.

Title
Intervertebral spacer device
Application Number
9/31241
Publication Number
5989291
Application Date
February 26, 1998
Publication Date
November 23, 1999
Inventor
Stephen Tatar
Montvale
NJ, US
James D Ralph
Oakland
NJ, US
Agent
Joseph P Errico Esq
Assignee
Third Millennium Engineering
NJ, US
IPC
A61F 2/44
View Original Source