Contemporary treatment of complex adult spine deformity using bone morphogenic protein: a comparative analysis of outcome and complication profiles

BACKGROUND CONTEXT: There is controversy surrounding the use of bone morphogenic protein (BMP-2) in spine surgery with multiple off-label uses. The widespread use of BMP-2 is spine deformity surgery remains unsupported by literature. PURPOSE: To assess outcomes in patients undergoing ASD surgery with or without BMP use. STUDY DESIGN/SETTING: Retrospective cohort. PATIENT SAMPLE: A total of 512 ASD patients. OUTCOME MEASURES: Health-related quality of life (HRQL) metrics, cost, quality-adjusted life years METHODS: ASD patients with fusions from thoracolumbar spine to pelvis with clinical and radiographic data were assessed for suitability. ASD diagnosed by SRS-Schwab radiographic criteria (SVA > 5cm, PI-LL > 10°, or PT > 20°). Patients were stratified on whether they received intra-operative BMP (BMP+) or not (BMP-). Means comparison testing and logistic regression analyzed differences between groups. Quality gained was calculated from ODI to SF-6D and translated to quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions for complications and comorbidities. RESULTS: There were 512 patients included (age: 59.9 ± 14.4 years, BMI: 27.0 ± 5.5 kg/m2, CCI: 1.64 ± 1.67); 81% of patients were female. 60% of patients had BMP-2 used during their surgery (60% BMP+). At baseline, BMP+ patients were older (62.5 vs 60.8 years, p<0.001), but there were no other differences between both groups. There were no differences between both groups in radiographic or HRQL metrics at each follow up timepoint (all p>0.05). In BMP+, the mean BMP/level ranged from 2.7 to 3.7 mg/level, with the highest doses at L5/S1 (3.7 ± 2.4). BMP was much more likely to be used at L5/S1 than any other level (OR 51.6, 95% CI: 5.8-461.2, p<0.001). BMP use was associated with higher supplemental rod use (OR: 7.0, 1.9 – 26.2, p=0.004), higher levels fused (OR: 1.1, 1.03 – 1.17, p=0.003) and greater neurological complications (OR: 5.0, 1.3 – 18.7, p=0.017). Controlling for rod use and levels fused, BMP use was not associated with a lower risk of mechanical complications (OR 0.3, 95% CI: 0.2 – 3.0), rod breakage (OR: 3.3, 0.6 – 18.7, p=0.182) or implant failure (OR: 0.3, 0.04 – 1.51). At 2 years, BMP+ had a higher overall cost ($108,062 vs $95,144, p=0.002), equivocal QALYs (0.163 vs 0.171, p=0.65) and lower cost effectiveness (p<0.001) at two years. CONCLUSIONS: The off-label use of biologics such as BMP-2 remains unsubstantiated by current literature. BMP use was associated with higher costs, but did not demonstrate superior radiographic or clinical outcomes at two years. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

Duke Scholars

Author Christopher Ignatius Shaffrey Orthopaedic Surgery

Author Peter Passias Orthopaedic Surgery