The Effect of Obesity on Clinical Outcomes After Lumbar Fusion

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To investigate and compare back and leg pain, and health-related quality of life measures in obese patients undergoing lumbar spine fusion, and to compare the results to nonobese patients. SUMMARY OF BACKGROUND DATA: Obesity is a growing healthcare crisis in the United States and an increasing number of patients undergoing spinal surgery are obese. Obesity is also associated with low back pain. Some obese patients with significant structural spine problems may be dismissed as having their pain only coming from their weight. We compared patient outcomes in obese and nonobese patients undergoing lumbar fusion surgery. METHODS: We retrospectively reviewed a single-center patient database of patients undergoing lumbar fusion and identified 270 patients with greater than 2-year outcome data. Body mass index (BMI) was calculated and patients were classified as obese (BMI >or= 30) or nonobese (BMI < 30). All patients completed Oswestry Disability Index (ODI), Short Form (SF)-36 questionnaires, and back and leg pain numerical rating scores before surgery and at 2 years. We compared clinical outcomes and complication rates in the 2 groups. RESULTS: The overall study group consisted of 109 obese patients and 161 nonobese patients. Both the obese and nonobese patients demonstrated significant improvements in back pain, leg pain, SF-36 physical composite summary (PCS), and ODI scores (P < 0.001) at 2-year follow-up compared with baseline. There was no significant difference in the mean improvements seen in obese patients compared with nonobese patients with respect to back pain, leg pain, or SF-36 PCS or ODI scores. Both SF-36 PCS (P = 0.037) and ODI score (P = 0.028) at 2-year follow-up were better in the nonobese patients compared with the obese patients. Overall complication rates were slightly higher in the obese group (P = 0.045), predominantly because of wound-related complications. CONCLUSION: Obese patients undergoing lumbar fusion achieve similar benefits to nonobese patients. Wound-related complications are more common in obese patients. Obese patients with otherwise good indications for lumbar fusion should not be denied this procedure because of their weight.