Obesity and perioperative adverse events in patients undergoing complex revision surgery for the thoracolumbar spine

BACKGROUND: There are no previous studies that evaluate the effect of obesity on patients undergoing complex revision thoracolumbar spine surgery. The primary objective was to determine the relationship between obesity and perioperative adverse events (AEs) with patients undergoing complex revision thoracolumbar spine surgery while controlling for psoas muscle index (PMI) as a confounding variable. The secondary objective was to determine the relationship between obesity and 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, and post-operative length of stay (LOS). METHODS: for females were used to define low muscle mass. A Spine Surgical Invasiveness Index (SSII) > 10 was used to define complex revision surgery. A multivariable logistic regression model was used to ascertain the effects of low muscle mass, obesity, age, and gender on the likelihood of the occurrence of any AE. RESULTS: A total of 114 consecutive patients were included in the study. Fifty-four patients were in the obese cohort and 60 patients in the non-obese cohort. There was not a significant difference in perioperative outcomes of both the obese and non-obese patients. There were 22 obese patients (40.7%) and 33 non-obese patients (55.0%) that experienced any AE (p = 0.130). Multivariable analysis demonstrated that individuals with low muscle mass had a significantly higher likelihood for an AE than individuals with normal or high muscle mass (OR: 7.53, 95% CI: 3.05-18.60). Obesity did not have a significant effect in predicting AEs. CONCLUSIONS: Obesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery. LEVEL OF EVIDENCE: III.