Introduction: Studies focusing on macroscopical shape and microscopical features have been conducted for decades to evaluate the anatomy of prostate apex. A initial description of nerve distribution along the prostatic capsule was provided by Eichelberg et al. (Eur Urol, 2007), highlighting a non-negligible number of nerves on the ventral part of the prostate. Authors recommended a high incision to achieve a nerve sparing technique on the anterior portion of the prostate, as a result of surgical evidence. While previous microscopical analyses were focused on specimens undergoing previous formalin-fixation and paraffin-embedding, the present study aims to assess apical microscopical anatomy on fresh samples, through the use of ex-vivo fluorescence confocal microscopy. Methods: Eleven slides from 9 patients undergoing non nerve-sparing robotic radical prostatectomy have been prospectively collected and analyzed. Following the acquisition of 1-mm transverse sections of the prostate apex, each specimen was stained in Acridine Orange for 30 seconds and then examined through fluorescence confocal microscopy (Vivascope, Mavig). Slides were split into sectors, similar to Eichelberg study: anterior, mid-lateral and postero-lateral aspects were investigated on each side of the slides. The main goal is to determine the amount of nerves surrounding each aspect of the apex. All slides were examined by two pathologists, an expert and a trainee (AC and CP), who counted every single nerve and ganglion on apical perimeter and in the peri-prostatic tissue. Results: Around the apical circumference, a total of 81 nerves were found. The majority (72%) of the nerves were detected in the postero-lateral region of prostatic apex (58), 22% in the lateral part (18) and 6% only (5 nerves) in anterior apex. Regarding the nerve count, there was a satisfactory level of agreement (K value of 0.75) between pathologists. In 4/11 slices, a segmental pseudocapsule composed by connective and muscle tissue was visible. Conclusions: To our knowledge, this is the very first depiction of nerve distribution on prostate apex on fresh specimens. In contrast with Eichelberg’s findings, in the anterior and mid-lateral aspects of the apex, an inferior amount of nerves was found. Despite the limited number of cases now available, a possible explanation for our discovery is the lack of shrinkage brought on by formalin fixation. Further research is encouraged to learn more about the location of the nerves on fresh material and to potentially guide surgical techniques for apical dissection. SOURCE OF Funding: None
