[Clinical study of lumbar fusion by hybrid construct of stem cells technique and biodegradable material].

Objective: To explorer the effectiveness of enriched bone marrow stem cells technique for lumbar fusion.

Methods: With the randomization and control principles, 2 graft materials [Enrichment bone marrow mesenchymal stem cells hybridized with beta-tri calcium phosphate (composite graft group), autologous iliac crest bone graft (autograft group)] were compared in posterior lumbar fusion procedures. 56 patients with degenerative disc disease, lumbar instability or spinal stenosis, were included. The volume of cells suspension in pre- and post-enrichment and the number of nucleated cells (NCs) were identified. The number of osteoprogenitor cells was estimated by counting the colony-forming units which express alkaline phosphatase (CFUs/ALP+). Then the efficiency of the enrichment was evaluated. Clinical follow-up with roentgenogram and Oswestry scale scores was performed for outcome evaluation.

Results: (249 +/- 31) ml bone marrow per patient from bilateral iliac crests was aspirated peri-operatively. About (43 +/- 11) ml enriched bone marrow was collected. The number of NCs was concentrated from (15.9 +/- 3.3) x 10(6)/ml to (44.1 +/- 10.8) x 10(6)/ml, CFUs/ALP+ was significantly increased from (118 +/- 86)/ml to(486 +/- 305)/ml. The follow-up was about (26.3 +/- 7.5) months. There was no significant differences in age, gender, disease and fusion segments between the two groups. The fusion rate was 93.3% and 96.2% for composite graft group and autograft group, respectively (chi2 = 0.2146, P = 0.6432). There was no difference in operation time between the two group (t = 0.5243, P = 0.6022), but blood loss in composite graft group was more than that in autograft group (t = 6.4664, P < 0.01). Cell salvage for auto-transfusion could transfuse back half of the blood loss during operation. No hematoma or chronic soreness in the bone marrow donor sites of composite graft group occurred, but a little exudation or moderate swelling in the wound happened in 4 cases which disappeared under medical treatment. Meanwhile, 15.4% patients had hematoma in the iliac bone donor site and 26.9% patients had chronic soreness, but no case had wound problem in autograft group. As for Oswestry scale scores, there was no significant difference between the two groups.

Conclusions: The enrichment technique of autologous bone marrow stem cells can greatly increase the concentration of MSCs. It is a rapid and safe method used peri-operatively. The composite material of enriched MSCs and porous beta-TCP is a good bone substitute in posterior spinal fusion.