Surgical Complications and Outcomes in Obese versus Non-obese Patients Undergoing Adult Degenerative Scoliosis Spine Surgery

Introduction: Obesity carries significant healthcare and economic burden and is associated with numerous co-morbid conditions including degenerative spine disease. Current literature examining differences in post-spine surgery outcomes affected by obesity has presented conflicting results. The goal of this study was to examine outcomes and complication rates of obese versus non-obese patients who underwent spine surgery for adult degenerative scoliosis deformities.

Methods: A retrospective case series study was conducted for 235 patients who underwent thoracolumbar adult spinal deformity (ASD) surgery (≥4 levels) at UTSW Medical Center. Patients were categorized into two cohorts based on their BMI: obese (BMI ≥30 kg/m2; n=81) and non-obese (BMI < 30 kg/m2; n=154). Demographics, clinical characteristics, peri-operative variables, and post-operative and patient-reported outcomes were analyzed. The Oswestry Disability Index (ODI), modified 5-item frailty index (mFI-5), and modified 11-item frailty index (mFI-11) questionnaires were used to analyze post-operative outcomes.

Results: African-American patients were more likely to be obese (p < 0.05, OR: 4.11) compared to Caucasian patients, who were more likely to be non-obese (p < 0.01, OR: 0.29). Intra-operatively, on average, obese patients were under anesthesia for longer time periods (p < 0.05) and had a higher estimated blood loss (p < 0.05). No significant differences were found in post-operative complication or mortality rates between the two cohorts. Obese patients had higher pre- and post-operative disability scores and were less likely to be discharged directly to home compared to non-obese patients (p < 0.05).

Conclusion : Obese patients undergoing spine surgery for degenerative scoliosis have increased surgical risk with respect to longer operative time, increased blood loss, and worse post-operative functional and disability status compared to non-obese patients. Obesity is a factor to be considered during pre-operative assessment in patients undergoing spine surgery. Future studies including multi-institutional reviews and examining the effect of pre-operative interventions targeting obesity on complications in degenerative scoliosis surgery will be needed.