The Effect of a Peritoneal Iliac Flap on Lymphocele Formation After Robotic Radical Prostatectomy: Results From the PLUS Trial

Abstract

To assess the effectiveness of a peritoneal flap on the formation of lymphoceles after robotic assisted radical prostatectomy with bilateral extended pelvic lymph node dissection. We conducted a single surgeon, assessor blinded prospective randomized controlled trial (the Prospective Lymphocele Ultrasound Study) in men undergoing robotic assisted radical prostatectomy with bilateral extended pelvic lymph node dissection. At the conclusion of the node dissection, patients were block randomized 1:1 to either standard of care (no bladder peritoneal flap) or to the creation of a bladder peritoneal flap. Lymphocele formation was assessed by pelvic ultrasound postoperatively. The primary outcome was lymphocele formation. Rates of lymphocele formation and complications were analyzed using chi-square. Other outcomes, including length of stay, number of lymph nodes removed, lymphocele volume, and quality of life measures, were analyzed by t-tests or Wilcoxon Ranked Sum Tests, as appropriate. An a priori power calculation was performed using O'Brien-Fleming alpha sharing for the interim analyses. Two preplanned interim analyses were performed when 45 and 90 patients per group had follow-up ultrasounds. A statistically significant difference in lymphocele formation was seen on the second interim analysis for 183 patients (4.3% vs. 15.6%, p=.011) stopping enrollment; this remained significant in the final analysis of 216 patients (3.6% vs 14.2%, p=.006). No other significant differences were observed. This prospective randomized trial supports the implementation of this simple modification for robotic assisted radical prostatectomy with bilateral extended pelvic lymph node dissection.