Anatomical retro-apical technique of synchronous (posterior and anterior) urethral transection: a novel approach for ameliorating apical margin positivity during robotic radical prostatectomy

Abstract

Objective: To describe a novel synchronous approach to apical dissection during robotic-assisted radical prostatectomy (RARP) which augments circumferential visual appreciation of the prostatic apex and membranous urethra anatomy, and assess its effect on apical margin positivity.

Patients and methods: Positive surgical margins (PSM) during RP predispose to earlier biochemical recurrence, and occur most frequently at the prostatic apex. Conventional apical transection after early ligation of the dorsal venous complex (DVC) remains suboptimal, as this approach obscures visualization of the intersection between prostatic apex and membranous urethra, leading to inadvertent apical capsulotomy and eventual margin positivity. A synchronous urethral transection commenced via a retro-apical approach was adopted in 209 consecutive patients undergoing RARP by one surgeon (A.T.) between April to September 2009. The apical margin rates for this group were compared with those of 1665 previous patients who received conventional urethral transection via an anterior approach after DVC ligation. Outcomes were adjusted for differences in clinicopathological variables. All RP specimens were processed according to institutional protocols, and examined by dedicated genitourinary pathologists. The location of PSMs was identified as apex, posterior, posterolateral, bladder neck, anterior, base, or multifocal.

Results: Patients receiving synchronous urethral transection had significantly lower apical PSM rates than the control group (1.4% vs 4.4%, P = 0.04). This marked improvement in the retro-apical group occurred despite a significantly higher incidence of aggressive cancer (≥ pT3a) documented on final specimen pathology (16% vs 10%, P = 0.027).Technical difficulty was encountered in three of 209 study patients, in whom urethral transection had to be completed using the classic anterior approach.

Conclusion: Improved circumferential visualization of the prostatic apex, membranous urethra and their anatomical intersection facilitates precise dissection of the apex and its surrounding neural scaffold, and optimizes membranous urethral preservation. This has significantly ameliorated apical PSM rates in patients undergoing RARP, despite having to deal with more aggressive cancer on final specimen pathology.