Hybrid Grafting Using Bone Marrow Aspirate Combined With Porous β-Tricalcium Phosphate and Trephine Bone for Lumbar Posterolateral Spinal Fusion

Abstract

A prospective, comparative study. We developed a hybrid graft (HBG) of porous β-tricalcium phosphate ceramics/percutaneously harvested bone sticks/autologous bone marrow aspirate for lumbar posterolateral fusion (PLF). The aim of this study was to investigate the efficacy of the HBG as a substitute for conventional corticocancellous iliac autografts. Iliac crest bone graft (ICBG) has been traditionally used as the golden standard for lumbar spinal fusion. The significant complication rate associated with harvesting corticocancellous ICBG, however, has encouraged development of alternative graft substitutes. From September 2005, 61 consecutive patients underwent decompressive laminotomy and 1-level instrumented PLF. Each patient in this study had the constructs of the HBG placed on 1 side of the intertransverse process gutter. An autologous local bone graft (LBG) harvested during decompressive laminotomy was placed on the other side as a control. Radiographic evaluation was performed at 6 months, 1 year after surgery, and subsequently on an annual basis. The fusion statuses on either side of vertebra were compared. The flexion-extension motion in the dynamic x-rays at the target level decreased over time. Only 1 case exhibited over 5° of angular motion 2 years after surgery. In the evaluation of fusion status, the fusion rate for the HBG side (68.9% at 6 months, 83.6% at 1 year, 93.5% at 2 years) was higher than that for the LBG side (49.2% at 6 months, 75.4% at 1 year, 89.1% at 2 years) with a significant difference at 6 months after surgery. No significant complications at the donor site were found postoperatively. The HBG promoted posterolateral spinal fusion without significant donor site morbidity. Because of its efficacy and safety, this hybrid construct seems promising as an alternative to conventional iliac bone grafts for lumbar spinal fusion.