Bone morphogenetic protein-2 against iliac crest bone graft for the posterolateral fusion of the lumbar spine: A meta-analysis

Off-Label Bone Morphogenetic Protein 2 Use Results in Successful Posterolateral Lumbar Fusion in a Veteran Population

INTRODUCTION

Patients within the US Veterans Health Administration (VA) system have higher rates of comorbidities and chronic pain, increasing risks of complications/poor outcomes following spine surgery. Although the use of bone morphogenetic protein 2 (BMP-2) is established for anterior lumbar interbody fusion, its indications for off-label use in posterolateral fusion are unclear. The objective of this study was to evaluate safety and utility of BMP-2 in posterolateral fusion through a 15-year experience at the VA.

METHODS

Patients underwent posterolateral lumbosacral fusions with BMP-2 by a single VA surgeon from January 1, 2005, to January 1, 2020. The primary outcome was fusion assessed through postoperative radiographs. Secondary outcomes included adjacent segment disease (ASD) and postoperative pain clinic utilization.

RESULTS

Sixty-eight patients underwent lumbosacral posterolateral fusion with BMP-2; 77.9% were discharged home and had no postoperative complications. All patients achieved bony fusion at a mean of 113.3 ± 59.9 days postoperatively. Five patients were diagnosed with cancer postoperatively, and eight patients required revision for ASD. No notable predictors of ASD exist. Preoperative opioid use predicted postoperative pain clinic utilization.

DISCUSSION

Posterolateral lumbar fusion with BMP-2 in veterans yields high fusion rates and favorable complication profiles and should be considered in multimorbid hosts.

STUDY DESIGN

Retrospective review of prospectively collected data.

Postoperative Lumbar Fusion Bone Morphogenic Protein-Related Epidural Cyst Formation

Bone morphogenetic protein is broadly used in spinal surgery to enhance fusion rates. Several complications have been associated with the use of bone morphogenetic protein, including postoperative radiculitis and pronounced bone resorption/osteolysis. Bone morphogenetic protein-related epidural cyst formation may represent another complication that has not been described aside from limited case reports. In this case series, we retrospectively reviewed imaging and clinical findings of 16 patients with epidural cysts on postoperative MR imaging following lumbar fusion. In 8 patients, mass effect on the thecal sac or lumbar nerve roots was noted. Of these, 6 patients developed new postoperative lumbosacral radiculopathy. During the study period, most patients were managed conservatively, and 1 patient required revision surgery with cyst resection. Concurrent imaging findings included reactive endplate edema and vertebral bone resorption/osteolysis. Epidural cysts had characteristic findings on MR imaging in this case series and may represent an important postoperative complication in patients following bone morphogenetic protein-augmented lumbar fusion.