Prostatic peripheral nerve distribution may impact the functional outcome of nerve-sparing prostatectomy

Abstract

To study microscopic patterns of remaining peripheral nerves (PN) after nerve-sparing (NS) radical prostatectomy (RP) and possible consequences for nerve preparation. Specimens from 27 patients (7=non-NSRP, 20=unilateral NS) were examined. Sections were investigated for PN content by immunoassaying. 120 whole-mounted slides were divided into four sectors, and extracapsular nerves were counted; the mean posterior/anterior ratio was calculated. Calculated ratios were correlated with the respective volumes of prostatic tissue (PV). After dividing the patient cohort into two subgroups, shared by the median value of the posterior/anterior nerve ratios, the absolute PN contents on the anterior surface of the NS sides were compared. Anatomical posterior nerve percentage in non-NS aspects ranged from 0.0-100.0 to 26.7-94.6% with a mean of 66.60±25.4% and 68.83±16.0% (>/<200μm, respectively). Individual ratios from two nerve categories showed significant correlation (P<0.008). Mean posterior ratios were 83.04/79.68 and 39.21/56.00, respectively. After unilateral NS, 3.17-fold (2.25 vs. 0.71 nerves, P=0.05) and 2.26-fold (21.54 vs. 9.53, P=0.08) nerve fibers were resected in the anterior area in comparison with type A. After unilateral NS, the variation impact on the anterior nerve content of the NS side could be demonstrated. The amounts of nerves localized on the anterior prostate after RP vary interindividually. Saving only a minor part of the anterior areas may have an impact on the quantity of excised nerves adjacent to the specimen and impair postoperative functional results. Especially for those patients without a major posterolateral bundle distribution, surgeons should adapt the procedure and start nerve preservation more anteriorly to maximize the probability of satisfactory postoperative functional results.