BMP Use and the Risk of Revision Surgery After Long Posterolateral Fusions in the Elderly.

STUDY

DESIGN

Retrospective database review.

OBJECTIVE OF THE STUDY: The objective of the study was to assess whether bone morphogenetic protein (BMP) decreases the risk of revision surgery in elderly patients treated with 3-7 level or 8 or greater level fusions.

SUMMARY OF BACKGROUND DATA: Revision spine surgery in the elderly is a complex undertaking, highlighting the importance of discovering methods to decrease the risk of repeat procedures. The role of BMP in modulating risk of future revision surgery is not well studied in the elderly.

MATERIALS AND

METHODS

The PearlDiver database (2005-2012) was queried for elderly adult spinal deformity patients treated with a primary thoracolumbar posterolateral fusion of 3 or more levels. To compare how BMP modifies revision surgery rates in 3-7 level versus 8 level or greater fusions, 4 mutually exclusive cohorts were created and matched to one another: 1043 patients treated with 8 or greater level fusions with BMP; 1111 patients with 8 or greater level fusions without BMP; 2813 patients with 3-7 level fusions with BMP; and 4770 patients with 3-7 level fusions without BMP. Revision and complication rates were compared. Complications included seroma formation, heterotopic ossification, and postoperative neuritis within 90 days.

RESULTS

Patients treated with BMP during an 8 or greater level fusion were significantly less likely to require a revision surgery than matched controls (relative risk, 0.75, P=0.015). BMP use was not associated with a decreased risk of revision surgery in 3-7 level fusions (relative risk, 0.89, P=0.20). Patients treated with BMP during 3-7 level fusions were significantly less likely to develop any of the assessed complications (P=0.02). There were no other significant differences in pairwise comparisons of subcohorts of each of the fusion lengths.

CONCLUSIONS

BMP use decreases revision rates in elderly adult spinal deformity patients treated with 8 or greater level fusions, but not in those treated with 3-7 level fusions.

LEVEL OF EVIDENCE: Level III.