Free-hand, transrectal ultrasound-guided hydrodissection of the retroprostatic space during robot-assisted radical prostatectomy: Impact on the learning curve

Abstract

Aim of the current study is to describe our technique of hydrodissection (HD) of the retroprostatic space (RPS) performed between the Denonvillier's fascia (DF) and prostatic capsule (PC) and to evaluate its impact on the outcomes of nerve-sparing robot-assisted radical prostatectomy (nsRALP) during the learning-curve period. This randomized study enrolled 25 consecutive male patients with indication of nsRALP. The HD and the subsequent dissection of the seminal vesicles (SVs) and RPS was performed by a resident in learning curve for RALP; the residual portion of RALP was performed by an expert. The perioperative, oncologic and functional outcomes of 2 groups of patients (Group A: nsRALP after HD of the RPS and Group B: standard nsRALP without HD) were compared. Two analyses were performed, considering a per-protocol (PP) population regarding only randomized patients with correct HD and an Intention-To-Treat (ITT) population regarding all randomized patients. In 4/14 (29%) of patients of Group A the injected fluid was not intraoperatively identified in the expected plane. The groups were statistically homogeneous in relation to the baseline variables. A statistically significant difference was observed between the SVs/RPS dissection time and the SVs-related estimated blood loss in both analyses. A significantly higher rate of dry patients was observed in group A at 1 month after nsRALP. A statistically significant correlation was observed between the effective time of dissection of the SVs and the postoperative IIEF-5 drop. The transrectal ultrasound-guided transperineal HD seems useful for the preliminary development of the RPS during the learning curve period of nsRALP. It seems associated with less time and blood loss for the dissection of the SVs and RPS. Studies on larger cohorts are needed to draw more robust conclusions.