Intervertebral disc prostheses.
METHODS
This article is based on a comprehensive review of the literature related to intervertebral disc prostheses.


OBJECTIVE
To compile an overview of the results and complications related to various types of lumbar and cervical disc replacements.


BACKGROUND
A functional disc prosthesis has been sought since the 1950s. Although there were a few early attempts, disc replacement did not become a viable therapy until the late 1980s. Devices that were used in Europe at that time are now being evaluated in the United States in clinical trials. Cervical disc replacements are currently in the early stages of development and evaluation.


METHODS
A thorough literature search was conducted to identify articles published on intervertebral disc prostheses. Proceedings from conferences were reviewed as well. Articles were classified by topics, including lumbar total disc replacement, disc nucleus replacement, and cervical disc replacement.


RESULTS
Results of total disc replacement are favorable, with 63-85% of patients having a good outcome. As with any procedure, issues related to patient selection, operative technique, and device size selection were learned from the early experiences with these devices. There has been only one disc nucleus replacement used in an appreciable number of patients. This has yielded good results, but there have been problems related to device displacement. There are increasing reports on the use of cervical disc replacements, but they are still in the early evaluation phases. However, as with the lumbar counterparts, new designs are being evaluated.


CONCLUSIONS
Although still in the early phases of development, functional disc replacement will become a part of the spine surgeon's armamentarium for the treatment of patients with disc-related pain unresponsive to nonoperative care. The future in this area is exciting and bright with the introduction of new materials and new designs for implants. However, as with any new technology, there must be careful consideration of the safety of the devices, and their effectiveness will only be determined in long-term follow-up studies.
Guyer
Richard D
RD
Texas Back Institute, Musculoskeletal Research Foundation, Texas Health Research Institute, Plano 75093, USA. rguyer@texasback.com
Ohnmeiss
Donna D
DD
D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D019736:Prostheses and Implants / Q000009:adverse effects / Q000706:statistics & numerical data / Q000639:trends; D016059:Range of Motion, Articular; D016896:Treatment Outcome