Single-level instrumented posterolateral fusion of lumbar spine with β-tricalcium phosphate versus autograft -: A prospective, randomized study with 3-year follow-up

Study Design. A prospective, randomized clinical study comparing beta-tricalcium phosphate (beta-TCP) with autograft bone graft with follow-up of 3 years. Objective. To determine the efficacy of beta-TCP as a bone graft substitute combined with local autograft obtained from decompression compared with the use of autologous iliac crest bone graft in single-level instrumented posterolateral lumbar fusion. Summary of Background Data. A variety of bone graft substitutes have been used in posterolateral lumbar fusion with different efficacy reported, but no controlled study was conducted on the clinical performance of beta-TCP in instrumented posterolateral lumbar fusion. Methods. Sixty-two patients with symptomatic degenerative lumbar spinal stenosis were treated with single-level instrumented posterolateral lumbar fusion. They were randomly assigned to fusion with beta-TCP combined with local bone obtained from the decompression (group A, n = 32) or autogenous iliac crest bone graft plus decompression bone (group B, n = 30). The patients were observed up for 3 years after surgery. The results were assessed clinically and radiographically. Results. There were no significant differences in recovery rate of Japanese Orthopedic Association score and SF-36 score at all time intervals. Successful radiographic fusion was documented in all patients in both treatment groups. All patients in group B, however, complained bone graft donor site pain although significant improvement of pain was observed during the follow-up. Conclusion. Instrumented posterolateral fusion with beta-TCP combined with local autograft results in the same radiographic fusion rates and similar improvement of clinical outcomes and life quality compared with autograft alone. The authors therefore recommend the use of beta-TCP as bone graft substitute for instrumented posterolateral fusion of lumbar spine to eliminate the need of bone grafting harvesting from the ilium.