Abstract
The current evidence for total disc replacement was assessed by performing a systematic review of the published literature. This search identified two randomised controlled trials (RCTs), two previous systematic reviews, seven prospective cohort studies, eleven retrospective cohort studies and eight case series. The RCTs involved the use of the Charité artificial disc and the Pro-Disc II total disc replacement. All papers analysed were classified according to their level of evidence as defined by the Centre for Evidence Based Medicine, Oxford, UK (www.cebm). For degenerative disc disease at L4/5 or L5/S1, both the clinical outcome and the incidence of major neurological complications following insertion of the Charité artificial disc were found to be equivalent to those observed following a single level anterior lumbar interbody fusion 2 years following surgery. However, only 57% of patients undergoing total disc replacement and 46% of patients undergoing arthrodesis met the four criteria listed for success. The range of flexion/extension was restored and maintained with the Charité artificial disc. The role for two or three level disc replacement in the treatment of degenerative disc disease remains unproven. To date, no study has shown total disc replacement to be superior to spinal fusion in terms of clinical outcome. The long-term benefits of total disc replacement in preventing adjacent level disc degeneration have yet to be realised. Complications of total disc replacement may not be known for many years. There are numerous types of disc prostheses and designs under study or in development. Well designed prospective RCTs are needed before approval and widespread application of this technology.