Predictors of prolonged operative time during robot-assisted laparoscopic radical prostatectomy

OBJECTIVE To determine risk factors for prolonged operative time (OT) during robot-assisted laparoscopic radical prostatectomy (RALP). Being able to predict prolonged OT is of pivotal importance both to the physician for patient counseling and to the hospital management. PATIENTS AND METHODS Retrospective review of patient records undergoing RALP between 2003 and 2009 at a tertiary academic center with a structured teaching program. The following variables were recorded: age, race, body-mass index (BMI), previous abdominal surgery (yes/no), nerve-sparing technique (yes/no), lymph nodes dissection (yes/no), pathological stage (organ-confined versus non), cumulative surgical experience with RALP (expressed as number of years since introduction of RALP at our center), prostate weight and OT calculated skin-to-skin by the anesthesiologists. Prolonged OT was defined as the upper quintile (20%) according to the distribution. Multivariate regression model was generated to assess potential predictors of prolonged OT. RESULTS A total of 523 records were retrieved. Caucasians accounted for 77.8% of the cohort. Median age was 60.3 years (interquartile range, IQR, 55.0-64.6 years), median BMI 28.1 (25.8-30.7 kg/m²), prostate weight 46.0 g (37.0-57.8 g). Eighty-six (16.4%) patients had previous abdominal surgery, lymph nodes dissection was performed in 341 (65.2%) and nerve-sparing technique was done in 310 (59.3%) cases. Median OT was 175 min (IQR 146-220 min). Prolonged OT was set at >230 min, thereby 105 (20.1%) records were classified as such. On multivariate analysis, cumulative surgical experience with RALP (P < 0.001), nerve sparing (P= 0.023) and prostate weight (P < 0.001) were independent predictors of prolonged OT. CONCLUSIONS Larger prostates are associated with longer OT and this effect is maintained independently of cumulative robotic experience that represents another independent factor in determining OT.