Surgical steps that elongate operative time in robot-assisted radical prostatectomy among the obese population

The association between increased body mass index (BMI) and prolonged operative time (OT) in robot-assisted laparoscopic radical prostatectomy (RLRP) has been suggested before. It is unclear, however, which RLRP step contributes to this finding. We aimed to assess the association between BMI and duration of RLRP steps.

Records of patients who underwent RLRP between 2003 and 2009 were reviewed retrospectively. Demographics (including BMI) and OT were recorded. We reviewed total OT (incision to closure) and separate duration of sequential steps of RLRP: In room to incision (preparation), incision to robot docking (port-placement), docking to endopelvic fascia dissection end (retroperitoneal space development), dorsal vein complex (DVC) control, DVC-control end to prostate detachment (prostate dissection), vesicourethral anastomosis (anastomosis), and undocking time (undocking). We divided this cohort into BMI groups (<25, 25.0 to 29.9, 30.0 to 34.9, and ≥35) and compared their characteristics and OT.

A total of 555 patients were analyzed. OT was significantly different across BMI groups with medians of 159, 181, 178, and 191 minutes for BMI <25, 25 to 29.9, 30 to 34.9, and ≥35 kg/m2, respectively (P = 0.002). For BMI <25, preparation and prostate dissection were significantly shorter. There was a correlation between higher BMI and longer time of prostate dissection with nerve-sparing technique (P = 0.016), but not with a non-nerve-sparing approach (P = 0.658). Higher BMI was associated with longer times of DVC-control and vesicourethral anastomosis (P = 0.048 and P = 0.035, respectively).

Higher BMI is significantly associated with prolonged total OT for RLRP with specific steps (preparation, nerve-sparing dissection, DVC-control, anastomosis) responsible for this result. These data need to be considered when planning RLRP in the obese population.