Can a bone marrow-based graft replacement result in similar fusion rates as rib autograft in anterior interbody fusion procedures for adolescent thoracolumbar scoliosis?

STUDY DESIGN: Nonrandomized consecutive case series comparing interbody spine fusion with autograft versus bone marrow-based graft replacement (BGR).

OBJECTIVES: Effectiveness of bone marrow-based graft versus rib autograft in achieving anterior interbody fusion of the thoracolumbar/lumbar spine.

SUMMARY OF BACKGROUND DATA: The use of bone marrow (BM) with graft materials was shown in a prior study to aid with bone regeneration. Limited clinical data are currently available to demonstrate the effectiveness of BM for spinal applications. Engineered matrices of collagen type I coated with hydroxyapatite and combined with BM have been safely used in both spinal and long bone applications.

METHODS: Nineteen consecutive patients from 2003 to 2006 underwent anterior interbody fusion through an anterior approach with dual-rod instrumentation and structural interbody support for thoracolumbar scoliosis. Within 19 patients, there were 42 disc levels treated with graft replacement material combined with BM (BGR+BM) and 25 disc levels with rib autograft. The mean follow-up time was 17 months with a minimum of 6 months. Clinical and radiographic data included Scoliosis Research Society (SRS)-22 questionnaires and pain and fusion assessments of posterior-anterior and lateral radiographs, collected preoperatively and at 6, 12, and 24 months, postoperatively.

RESULTS: At 6 months, 72% of BGR+BM segments versus 44% of autograft segments were defined as fused. All BGR+BM segments were fused by 12 months, and all autograft segments were fused by 24 months. There was no pseudoarthrosis or instrumentation failure, and interbody fusion rate was 100%. The average correction was 73.5+/-13.5%. The overall loss of correction from the immediate alignment to postoperative follow-up was less than 4%. There was no loss of sagittal plane alignment or measured kyphosis. No morbidity was observed at the BM aspiration site.

CONCLUSIONS: Anterior spinal fusion using bone marrow-based graft substitutes for thoracolumbar adolescent idiopathic scoliosis demonstrated equivalent results to rib autograft when used with dual-rod instrumentation and structural support. In this patient series, the rate of fusion was faster in the bone marrow-treated segments. These results suggest that for patients as described in this cohort, bone marrow-based graft replacements can thus be used as an alternative, or adjunct, to autograft to achieve interbody fusion in scoliosis surgery.