Long-term clinical results following Charite III lumbar total disc replacement

Background Context Lumbar total disc replacement (TDR) operation represents an alternative to lumbar fusion for the treatment of symptomatic lumbar intervertebral disc degeneration and has gained increasing attention in recent years. Purpose This study aimed to assess clinical outcomes in a cohort of patients with TDR and the long-term survival rate of the prostheses. Study Design This is a retrospective, single-center clinical study. Patient Sample The sample comprised 30 patients, giving a total of 35 prostheses after an average follow-up (FU) of 15.2 years following TDR, which was performed for the treatment of lumbar degenerative disc disease. Outcome Measures Clinical evaluation included visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiological parameters of intervertebral disc height (IDH), range of motion (ROM), lumbar lordosis, lumbar scoliosis, and prosthesis position were evaluated in surgical and adjacent levels. Complications and re-operation rates were also assessed. Methods Clinical evaluation and radiological parameters were evaluated preoperatively and at final FU. All data were collected by members of our department, including research assistants and nurses who were not involved in the decision making of this study. Results Thirty of the 35 patients participated in the final FU. The cumulative survival rate of the prosthesis at a mean FU of 15.4 years was 100%. The clinical success rate was 93.3%. The VAS and ODI scores at final FU were significantly lower than preoperatively (p<.001). The average ROM of the operated and superior adjacent segment decreased significantly at the final FU, whereas the inferior adjacent segment was not affected. The IDH of all surgical and adjacent levels were well maintained at the final FU. Ten patients had a lumbar scoliosis >3° and the mean angle was 8.5°, of which 7 had left convex curvature. Three prostheses were offset more than 5 mm from the midline on the coronal plane. Four prostheses showed subsidence. Twenty-six operative segments and five adjacent segments showed heterotopic ossification. Two patients of the total 35-patient cohort underwent a secondary operation. Conclusions Satisfactory clinical results and good prosthesis survival can be achieved in the long term. Lumbar TDR surgeries also have the potential to reduce the incidence of adjacent segment disease.