Postoperative Complications Associated with rhBMP2 use in Posterior Lumbar Fusion

Abstract

IntroductionThe growing number of degenerative conditions in aging population has contributed to the increased rates of lumbar posterior spinal fusion (PLF). While PLF has been shown to be effective for the treatment of various different spinal disorders, variations in surgical technique (such as bone graft used) for PLF have potential for different complication profiles. Human recombinant bone morphogenetic protein 2 (rhBMP2) is a bone graft material commonly used in the US to enhance spinal fusion rates after PLF. There are some reports of complications related to the use of rhBMP-2 in PLF arising from relatively small case series. Aim of our study was to quantify the frequency of various complications in elderly patients undergoing PLF with and without rhBMP2. Material and MethodsWe queried the orthopaedic subset of the Medicare database (PearlDiver) between 2005 and 2011. Current Procedure Terminology (CPT) codes were used to identify patients undergoing PLF procedures with and without rhBMP2, and International Statistical Classifcation of Diseases 9 (ICD-9) codes were used for complications. Complication and re-operation rates were analyzed within 1 year after the index procedure. Complications included: Acute Renal Failure, Deep Vein Thrombosis, Dural Tear, Hematoma, Heterotopic Ossification, Incision and Drainage, Myocardial Infarction or other cardiac complication, Nerve, Osteolysis, PLF Reoperation, Pneumonia, Pseudoarthrosis, Pulmonary Embolism, Radiculopathy, Respiratory Complications, Sepsis, Urinary Retention, Urinary Tract Infection, Mechanical (failure of other internal orthopedic device, implant, and graft) and Wound Complications. Chi-square analysis was used to calculate the complication differences between the groups. ResultsThere were 20,143 patients who underwent a PLF from 2005–2011, and 27% (5421) of those cases received rhBMP2, while 73% (14722) had the PLF procedure without it. The majority of PLF cases were female (62%) and 65–69 years of age (27%) patients. The overall complication rate was similar between the rhBMP2 and no-rhBMP2 groups, 78.8% and 76.4%, respectively. However, most of the complications had a significantly lower rate in the rhBMP2 group compared with the no-rhBMP2 group (Dural tear 2.2% versus 3%; Incision and Drainage 6.9% vs 7.8%; Myocardial Infraction 3.8% vs 4.4%; Nerve 1.1% vs 2%; Pulmonary Embolism 2.2% vs 2.8%; Radiculopathy 9.4% vs 11.1%; Sepsis 3% vs 3.9%; Wound 8.2% vs 9.6%, respectively). Complications that were in the rhBMP2 group were Mechanical 8% vs 6.2%; Pseudoarthrosis 3% vs 1.8%; Urinary retention 9.9% vs 8.7% (p < 0.05) and Urinary Tract Infection 30.30% vs 29.60%. Interestingly, heterotopic ossification, demonstrated less than 11 patients in both groups.