Inpatient Outcomes and Postoperative Complications After Primary Versus Revision Lumbar Spinal Fusion Surgeries for Degenerative Lumbar Disc Disease: A National (Nationwide) Inpatient Sample Analysis, 2002-2011

INTRODUCTION: The present study investigates outcomes in patients undergoing elective primary versus revision fusion surgery for lumbar degenerative pathologies with the use of a large population based database. METHODS: A total of 126,044 patients registered in the National Inpatient Sample (NIS) database were identified to have undergone elective fusion of the lumbar spine (primary fusion: 94%; redo fusion: 6%) for degenerative pathologies, between 2002 and 2011. A multivariable logistic regression model was built that adjusted for patient demographics and clinical and hospital characteristics to explore clinical outcomes and postoperative complications. RESULTS: The mean age of the cohort was 54.91 +/- 13.98 years, and 58% were women. Multivariable regression analysis revealed patients undergoing redo lumbar fusion had a greater likelihood for an unfavorable discharge (odds ratio [OR] 1.17; 95% confidence interval [95% CI] 1.08-1.26; P < 0.0001), prolonged length of stay (OR: 1.80; 95% CI 1.68-1.92; P < 0.0001), greater hospital charges (OR 1.60; 95% CI 1.51-1.71; P < 0.0001), neurologic complications including dural tears and nerve root injuries (OR 2.06; 95% CI 1.80-2.37; P < 0.0001), deep venous thrombosis (OR 2.35; 95% CI 1.76-3.14; P < 0.0001), pulmonary embolism (OR 1.72; 95% CI 1.45-2.03; P < 0.0001), would infections (OR 2.40; 95% CI 1.79-3.22; P < 0.0001) and wound complications (OR 1.59; 95% CI 1.32-1.91; P < 0.0001), and gastrointestinal complications (OR 1.23; 95% CI 1.04-1.45; P = 0.016), compared with patients undergoing a primary lumbar fusion procedure. CONCLUSIONS: The association of a likely postoperative complication in patients undergoing revision lumbar spine fusion compared with those undergoing primary fusion procedures at the same region of the spine is quantified. Our analysis provides baseline estimates that could aid in pre-operative risk stratification and as an adjunct in patient education and counseling, and policy makers for higher reimbursements for these sicker patients.