Beta tricalcium phosphate: observation of use in 100 posterolateral lumbar instrumented fusions

BACKGROUND: Beta tricalcium phosphate (B-TCP) is increasingly used to supplement lamina autograft to perform posterolateral lumbar-instrumented arthrodesis. PURPOSE: To determine the radiographic arthrodesis and pseudarthrosis rates after multisegment lumbar laminectomies and one- or two-segment posterolateral instrumented fusion using lamina autograft and an artificial bone graft expander B-TCP (Vitoss; Orthovita, Malvern, PA, USA). STUDY DESIGN/SETTING: To document radiographic arthrodesis/pseudarthrosis rates using lamina autograft and B-TCP. PATIENT SAMPLE: One hundred patients with lumbar spinal stenosis underwent multisegment laminectomies (average 3.6 segments) and one- (78 patients) or two- (22 patients) segment posterolateral instrumented arthrodesis. OUTCOME MEASURES: Two-year postoperative outcomes were assessed using Short-Form 36 questionnaires. METHODS: The arthrodesis mass consisted of lamina autograft and B-TCP. Two independent neuroradiologists, using both dynamic X-rays and 2D-CT studies performed 3, 4.5 6, and Lip to 12 months postoperatively, documented radiographic arthrodesis progession. RESULTS: One-segment arthrodesis was performed in 79 patients 74 (93.7%) were radiographically fused early (6.5 postoperative months), 2 (2.5%) fused late (6.5-12 months). and 3 (3.8%) exhibited pseudarthrosis. Two-segment arthrodesis was performed in 21 patients 14 (66.7%) radiographically fused early, 5 (23.8%) fused late, and 2 (9.5%) exhibited pseudarthrosis. Although chi-square analyses revealed a significant increase in the number of late radiographic fusions Occurring for patients undergoing two-level arthrodesis, no significant difference in radiographic pseudarthrosis rates was noted between the two patient populations. In both groups, Short-Form 36 questionnaires revealed nearly comparable maximal improvement oil seven of eight Health Scales by the second postoperative year. CONCLUSIONS: At 6.5 months after multisegment lumbar laminectomies with posterolateral instrumented lumbar arthrodesis using lamina autograft/B-TCP, more one-segment (93.7%) versus two-segment (66.7%) radiographic arthrodesis occurred. By 1 year after operation, there was no significant difference in fusion rates between one- and two-segment radiographic arthrodeses. (C) 2009 Elsevier Inc. All rights reserved.