General Session: Adult Spinal Deformity - Hall F

Presented by: P. Passias

Author(s):

P. Passias(1), G. Poorman(1), S. Horn(1), C. Jalai(1), C. Bortz(1), F. Segreto(1), D. Ge(1), C. Varlotta(1), N. Worley(1), S. Yang(1), C. Poorman(1), J. Buza(1), A. Boniello(1), A. Lee(1), S. Vira(1), B. Diebo(2), V. Lafage(3), F. Schwab(3), T. Protopsaltis(1), T. Errico(1)

(1) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(2) SUNY Downstate Medical Center, Department of Orthopaedic Surgery, Brooklyn, NY, United States
(3) Hospital for Special Surgery, Department of Orthopaedic Surgery, New York, NY, United States

Abstract

Introduction: Though iliac crest bone grafts (ICBG) during posterior lumbar spinal fusions represents the gold standard, there are documented complications associated with its use, including donor site morbidity increased operative time, and added blood loss. Using bone marrow aspirate concentrate (BMC) and allograft has produced promising results in orthopaedic trauma procedures and single level spinal fusions, with reported similar osteoconductive and osteoinductive effects as ICBG. This study compares the efficacy of BMC+allograft to ICBG, taking into account the fusion status and patient-reported outcomes for patients undergoing muli-level posterior lumbar or thoracolumbar spinal fusions at higher-risk for nonunion.

Methods: This prospective study was conducted at a single institution, and included patients ages >18 years. All patients received posterior lumbar fusion performed by an open posterior approach. If more than 4 levels of fusion was performed, including extension to the sacrum, an interbody was performed at the L5-S1 level and bilateral iliac fixation was performed. Enrolled patients were randomized in a 2:1 ratio into two study arms with respect to graft adjunct: BMC+allograft or ICBG. Collected data included full-length radiographs at baseline, 6 weeks, 3 months, 6 months, 1 year, and 2 years post-operative. CT scans were obtained at 1 year post-operative. Health-related quality of life (HRQoL) scores were obtained at these time points, and included the Oswestry Disability Index (ODI), Short Form-12 (SF-12), and numeric pain rating scale. Fusion assessment was performed by CT and dynamic radiographs by an independent radiologist.

Results: 27 patients were randomized in a 2:1 fashion in the study consisting of 17 patients receiving BMC and 10 receiving ICBG. Mean age was 56 years, 48% of patients were smokers, and 40.7% of patients had a history of previous spinal surgery. Average fusion construct was 6.0 levels in the BMC cohort (range: 2 levels-23 levels) and was 6.23 levels in the ICBG group (range 2 levels- 8 levels), p=0.935. EBL (average 2231 ml) and OR time (average 8.02 hours) were similar between groups, p>0.05. There was no significant intraoperative complications related to BMC or ICBG protocol. Within the 2-year follow-up period, there were 7 complications in the BMC group (41.1%) and 4 in the ICBG group (40%). ICBG patients had greater incidence of rod breakage (BMC: 0% vs. ICBG: 25%, p=0.024). 88.2% of BMC patients were graded 'fused' at 1-year follow-up, and 60% of ICBG patients (p=0.088). 5.9% of BMC patients were graded 'bilateral pseudarthrosis', and 30% of ICBG patients (p=0.088). An average 2 billion 60 million nucleated cells were delivered per patient. This did not show correlation with fusion score (p=0.742).

Conclusion: In long fusions for adult spinal deformity, where autologous graft is limited, bone marrow concentrated via centrifuge is a viable alternative to iliac crest bone graft. The current study found a decrease in hardware failures in patients with BMC compared to ICBG, and a trend towards better fusion scores (>0.05, but < 0.1).