Intervertebral disc arthroplasty

An intervertebral disc arthroplasty is a neurosurgical procedure consisting in the replacement of a damaged intervertebral disc (previously removed through a discectomy procedure) with a synthetic prosthesis; it also goes under the common name of "artificial disc replacement".

Intervertebral disc arthroplasty is an alternative to vertebral fusion procedures, which also aim to preserve vertebral stability, but limit the range of movement. The insertion of an artificial disc allows to retain the original physiologic makeup of the spine, and is expected to avoid premature breakdown of fused vertebrae (a known long-term complication of vertebral fusion surgery).

Clinical use
Intervertebral disc arthroplasty has been used for over a decade in many countries, and especially in Europe and Japan, and performed at one or two levels at the same time. On the other hand, it is not yet widely available in the United States of America, where only two brands of artificial discs have been FDA-approved for use, and only to replace a single disc at a lumbar level (either L4/L5 or L5/S1): these are Charite by DePuy Acromed and ProDisc by Synthes (the latter was investigated by Jack Zigler). A third brand (Prestige) has been tested in a U.S. clinical trial for cervical arhtroplasty, and patients have been found to show "improved neurological success at 24 months and improved overall success". Two-level disc replacement is even rarer in the United States.

Partial intervertebral disc arthroplasty
Intervertebral disc arthroplasty is usually performed to replace one or more whole intervertebral disc ("full" disc replacement), but partial replacement techniques are also under development to replace only the nucleus pulposus (the central, softer portion of the intervertebral disc).