Correlation of histomorphologic findings and partial neurovascular bundle preservation during laparoscopic and robotic radical prostatectomy

The objective of this work was to compare the amount of residual periprostatic tissue for radical prostatectomy performed by the partial NS (PNS) technique with that performed by the nerve-sparing (NS) or wide-resection (WR) techniques. Retrospective histomorphologic evaluation of radical prostatectomy specimens (RPSs) from patients undergoing laparoscopic radical prostatectomy (LRP) or robot-assisted radical prostatectomy (RARP) was performed. The posterolateral regions corresponding to the neurovascular bundle in RPSs from 48 patients who had undergone NS, PNS, or WR during LRP (n = 30) or RARP (n = 18) were examined by two pathologists unaware of the technique used. The RPSs were evaluated at the base, mid-gland, and apex. The amount of periprostatic tissue at each site was recorded. Measurements were analyzed by use of a linear mixed model. For both LRP and RARP, each gradation of nerve-preservation was associated with periprostatic tissue, except PNS and WR did not differ for LRP at the apex and base or for RARP at the apex, mid-gland, and base. For LRP, a greater amount of tissue was on the left side of the prostate than on the right at the mid-gland level (P = 0.004) whereas for RARP the opposite was found (P = 0.024). Of 18 separate analyses, 13 were significantly associated. The study is limited by its retrospective design. The amount of periprostatic tissue in the neurovascular bundle area correlates well with the nerve-preservation approach used during LRP and RARP, providing anatomic evidence supporting the PNS approach. We also describe a novel finding of laterality bias at the mid-gland level in LRP and RARP specimens.