Findings in 67 patients with recurrent or persistent symptoms after implantation of a disc prosthesis for low back pain

Objective. To determine the symptoms in patients who presented with persistent or recurrent backache or leg pain after implantation of an artificial disc prosthesis. Design. Descriptive. Method. During the past II years in the Maastricht University Hospital (n = 65) and the Utrecht University Medical Centre (n = 2), 67 patients were seen with persistent or recurrent backache or leg pain in whom, an average of 53 months previously, one or more SB Charite-III lumbar-disc prostheses had been implanted elsewhere. The results were evaluated. Results. The most prominent findings were: migration of the prosthesis (n = 6); subsidence into the vertebra (n = 35); disc degeneration at one or more neighbouring levels (n = 34) and arthrosis of facet joints (n = 24). In 9 cases, rupture of the metal wire around the polyethylene core was observed and in 5 cases there were radiological signs of polyethylene wear. Re-operation (spondylodesis) was generally unsatisfactory if the prosthesis was left in place. In 21 patients, the prosthesis was removed; all specimens showed polyethylene wear or rupture. Conclusion. Published results are mostly case series and suffer from observer bias; moreover, the benefits are moderate. Given the uncertain role of disc degeneration in patients with chronic backache, the real risk of complications and the uncertain advantages, the implantation of a disc prosthesis is difficult to defend.