Is there a proper pelvic size for an extraperitoneal robot-assisted radical prostatectomy?

Background: A narrow pelvis can potentially complicate an extraperitoneal radical robot-assisted prostatectomy (RAP). We report our experience with RAP and evaluate whether a narrow pelvis can affect treatment outcomes after extraperitoneal RAP. Materials and Methods: We prospectively evaluated 50 patients who underwent RAP during a 2-month period using the extraperitoneal approach. To approximate the relative size of the field available for working using the extraperitoneal approach, the arc length between the anterior superior iliac spines was estimated with the umbilicus as the center of the circle. Patients with an arc length measuring < 33 cm were compared with those with an arc length >= 33 cm. Additional parameters evaluated included age, total operating time, estimated blood loss, prostate-specific antigen (PSA) level, pathological stage and Gleason grade, intraoperative and perioperative complications, surgical margin status, and continence at 3 months. Results: Twenty-eight (56%) patients had an arc length < 33 cm and twenty-two (44%) patients had an arc length >= 33 cm. When comparing the two groups, no statistically significant difference (P > 0.05) was noted in age, PSA level, blood loss (161 v 163 mL), operative time (174 v 176 min), and total positive margin rates (14% v 13.6%). The continence rate at 3 months was 66.6% and equal for both groups. Conclusion: In our experience, a narrow pelvis did not significantly affect operative outcome in patients undergoing an extraperitoneal radical RAP. Although this variable should be taken into account, it should not be a primary factor in deciding the route of access.