Fusion rates after thoracoscopic release and bone graft substitutes in idiopathic scoliosis

STUDY DESIGN. A retrospective assessment of fusion rates using either morselized allograft bone or demineralized bone matrix (DBM) following video-assisted thoracoscopic surgery (VATS) in idiopathic scoliosis. OBJECTIVE. To compare fusion rates between allograft bone and demineralized bone matrix (Grafton DBM Flex) following VATS using on standard standing lateral spine radiographs. SUMMARY OF BACKGROUND DATA. Both VATS and bone graft substitutes are accepted surgical techniques. However, their concomitant use in spinal deformity surgery has not been previously reported. Bone graft substitute has the advantage of decreasing operative time, blood loss, and donor site morbidity associated with autografts. METHODS. Anterior thoracic discectomies were performed using VATS. Forty patients with 1 year or more follow-up were evaluated-12 with morselized allograft bone (Allograft group) and 28 with folded Grafton DBM Flex (DBM group). Factors analyzed included age, number of anterior levels fused, operative time, anterior perioperative blood loss, curve correction, and fusion rates. Clinical and radiographic evaluations were performed before surgery and at month, 1 year, and at most recent follow-up. Interbody fusion was assessed on standing lateral radiographs using the Newton et al 4-level grading scale. RESULTS. There were no significant differences in age at surgery, number of anterior vertebral levels fused, anterior operative time per level, anterior intraoperative blood loss, chest tube drainage and duration, or total perioperative anterior blood loss between the 2 groups. Percent curve correction from before surgery to the most recent follow-up were very similar in both Allograft (68%) and DBM groups (67%). At most recent assessment, 60 of 73 disc spaces (82%) in the Allograft group and 100 of 109 disc spaces (92%) in the DBM group were rated as radiographically fused (Newton et al Grade I and II). There was no significant difference between the 2 groups (P = 0.088). No patients were observed to have crankshaft, pseudoarthrosis or hardware failure. There were no complications related to the bone graft material used. CONCLUSION. Demineralized bone matrix (Grafton DBM Flex) seem to be an effective bone graft substitute in thoracoscopic surgery for idiopathic scoliosis.