Effect of Body Mass Index on Early Outcomes of Minimally Invasive Degenerative Lumbar Surgery

This retrospective study examined the early outcomes of healthy weight and severely obese subjects who underwent minimally invasive (MI) fusion and decompression surgery for degenerative lumbar disease at one to two spinal levels. A single surgeon (D.A.) operated on all subjects. Subjects were categorized based on body mass index [normal (18.5–24.9 kg/m2) or severely obese (over 35 kg/m2)]. Surgical data included blood loss, hospital length of stay, narcotic use, discharge disposition, and postoperative infection. Data were compared using Levene’s test for equality of variances, t test for equality of means,
Pearson chi-square test, and Cramer’s V correlation test (˛  .05 for all). SPSS software was utilized for all tests. Significant differences between the groups included blood loss, hospital length of stay, and early narcotic use. In the early postoperative setting, healthy weight subjects went home sooner and lost less blood, but needed more narcotic prescriptions filled than their obese counterparts. The use of MI spinal surgery in the severely obese population provides manageable issues for the patient and no significant complications when compared with the healthy weight population, indicating that it is a good alternative for obese patients. (Journal of Surgical Orthopaedic Advances 24(1):12–17, 2015) Key words: body mass index, decompression, fusion, minimally invasive surgery, spine