Impact of obesity on complications and outcomes: a comparison of fusion and nonfusion lumbar spine surgery.

OBJECTIVE Prior studies have shown obesity to be associated with higher complication rates but equivalent clinical outcomes following lumbar spine surgery. These findings have been reproducible across lumbar spine surgery in general and for lumbar fusion specifically. Nevertheless, surgeons seem inclined to limit the extent of surgery, perhaps opting for decompression alone rather than decompression plus fusion, in obese patients. The purpose of this study was to ascertain any difference in clinical improvement or complication rates between obese and nonobese patients following decompression alone compared with decompression plus fusion for lumbar spinal stenosis (LSS). METHODS The Quality Outcomes Database (QOD), formerly known as the National Neurosurgery Quality and Outcomes Database (N²QOD), was queried for patients who had undergone decompression plus fusion (D+F group) versus decompression alone (D+0 group) for LSS and were stratified by a body mass index (BMI) ≥ 30 kg/m² (obese) or < 30 kg/m² (nonobese). Demographic, surgical, and health-related quality of life data were compared. RESULTS In the nonobese cohort, 947 patients underwent decompression alone and 319 underwent decompression plus fusion. In the obese cohort, 844 patients had decompression alone and 337 had decompression plus fusion. There were no significant differences in the Oswestry Disability Index score or in leg pain improvement at 12 months when comparing decompression with fusion to decompression without fusion in either obese or nonobese cohorts. However, absolute improvement in back pain was less in the obese group when decompression alone had been performed. Blood loss and operative time were lowest in the nonobese D+0 cohort and were higher in obese patients with or without fusion. Obese patients had a longer hospital stay (4.1 days) than the nonobese patients (3.3 days) when fusion had been performed. In-hospital stay was similar in both obese and nonobese D+0 cohorts. No significant differences were seen in 30-day readmission rates among the 4 cohorts. CONCLUSIONS Consistent with the prior literature, equivalent clinical outcomes were found among obese and non-obese patients treated for LSS. In addition, no difference in clinical outcomes as related to the extent of the surgical procedure was observed between obese and nonobese patients. Within the D+0 group, the nonobese patients had slightly better back pain scores at 2 years postoperatively. There may be a higher blood product requirement in obese patients following spine surgery, as well as an extended hospital stay, when fusion is performed. While obesity may influence the decision for or against surgery, the data suggest that obesity should not necessarily alter the appropriate procedure for well-selected surgical candidates.