Introduction: Bone morphogenetic protein (BMP) is considered off-label when used to augment spinal arthrodesis in children and adolescents. There is a paucity of longer-term information on BMP use in this population. The purpose of this study was to determine the rate of BMP utilization in pediatric spinal arthrodesis, assess factors associated with BMP use in this population, and evaluate long-term outcome.
Methods: Spinal arthrodeses in patients 18 years and younger performed in New York State between 2004 and 2014 were identified through the Statewide Planning and Research Cooperative System database. All cases had a minimum 1-year follow-up. The primary outcome was revision arthrodesis. The primary outcome, as well as short-term and longer-term complications were identified using time-to-event analysis. Multivariable Cox proportional hazards models were used to assess the association between BMP and outcomes.
Results: Of 7312 children and adolescents who underwent spinal arthrodesis, 462 (6.7%) received BMP. Utilization spiked between 2008 and 2010 when (8.6%) of cases received BMP, but subsequently BMP use returned to pre-2008 levels (2004 to 2007: 5.3%; 2011 to 2014: 5.5%). BMP was more likely to be used in children who were older (P=0.027), white and with higher mean family income (P<0.001 for race and income). BMP was more likely to be used for revision surgery, 2 to 3 level fusions, and spondylolisthesis (P<0.001 for all). Revision rates did not differ based on BMP utilization status. Patients receiving BMP did not have increased risk of short-term complications although at 5-year follow-up, BMP was associated with a statistically significant increased risk of mechanical complications (hazard ratio 1.48; 95% confidence interval, 1.02-2.14).
Conclusions: Off-label use of BMP for pediatric spinal arthrodesis increased until 2008 and now appears to be decreasing. Racial/ethnic minorities and lower socioeconomic status patients are less likely to receive BMP. The rate of revision after spinal arthrodesis does not differ between those treated with and without BMP. Further long-term studies are required to delineate appropriate guidelines for BMP utilization in children.
Level of evidence: Level III.