Abstract
Background
Posterolateral fusion (PLF) is a commonly accepted surgical procedure and overall the most common technique performed to obtain fusion in the lumbar spine. Harvesting autologous bone from the iliac crest is associated with increased operation time, blood loss, and chronic donor site pain. Allograft material has an insufficient osteoinductive potential. Bone marrow concentrate (BMC) could be an option how to promote allograft PLF healing. The purpose of the presented study was to investigate the validity of BMC addition to allografts in instrumented lumbar PLF surgery.
Methods
The study was prospective, randomised, controlled and blinded. Eighty patients with degenerative disease of the lumbar spine underwent instrumented (S4, Aesculap, Tuttlingen, Germany) lumbar or lumbosacral PLF. In forty cases, the PLF was done with spongious allograft chips alone (Group I). In another forty cases, spongious allograft chips were mixed with BMC (Group II), where the mesenchymal stem cell (MSCs) concentration was 1.74 × 104/L at average (range, 1.06–1.98 × 104/L). Patients were scheduled for anteroposterior and lateral radiographs at 12 and 24 months after the surgery and for CT scanning at 24 months after the surgery. Fusion status and the degree of mineralization of the fusion mass were evaluated separately by two radiologists blinded to patient group affiliation.
Results
In Group I at 12 months, the bone graft mass was assessed in X-rays as fused in no case (0 %) and at 24 months in 4 cases (10 %). In Group II, 6 cases (15 %) achieved fusion at 12 months and 14 cases (35 %) at 24 months. The statistically significant difference between both groups was proven for complete fusion at 12 months (p = 0.041) and at 24 months (p = 0.011), too. CT scans showed that 16 cases (40 %) in Group I and 32 cases (80 %) in Group II had evidence of at least unilateral continuous bridging bone between neighboring vertebrae at 24 months (p < 0.05). We have confirmed the hypothesis that the autologous BMC together with the allograft is a better alternative for the PLF than the allograft alone.
Conclusions
The use of autologous MSCs in form of the BMC in combination with allograft is an effective option how to enhance the PLF healing. Allograft by itself is not an effective material as a posterior onlay graft for the PLF in adult surgery.
