Impact of body mass index on perioperative outcomes during the learning curve for robot-assisted radical prostatectomy.

INTRODUCTION: Previous studies of robotic-assisted radical prostatectomy (RARP) have suggested that obesity is a risk factor for worse perioperative outcomes. We evaluated whether body mass index (BMI) adversely affected perioperative outcomes.
METHODS: A prospective database of 153 RARP (single surgeon) was analyzed. Obesity was defined as BMI >/= 30 kg/m(2); normal BMI < 25 kg/m(2); and overweight as 25 to 30 kg/m(2). Two separate analyses were performed: the first 50 cases (the initial learning curve) and the entire cohort of 153 RARP.
RESULTS: In the initial cohort of 50 cases (14 obese patients), there was no statistically significant difference with regards to operative times, port-placement times and estimated blood loss (EBL). Length of stay (LOS) was longer in the obese group (4.3 vs. 2.9 days); BMI remained an independent predictor of increased LOS on multivariate linear regression analysis (p = 0.002). There was no statistically significant difference in the postoperative outcomes of leak rates, margin rates and incisional herniae. In the entire cohort, when comparing obese patients to those with a normal BMI, there was no statistically significant difference in operative times, EBL, LOS, or immediate postoperative outcomes. However, on multivariate linear regression analysis, BMI was an independent predictor of increased operative time (p = 0.007).
CONCLUSION: Obese patients do not have an increased risk of blood loss, positive margins or the postoperative complications of incisional hernia and leak during the learning curve. They do, however, have slightly longer operative times; we also noted an increased LOS in our first 50 cases.