Topographical anatomy of periprostatic and capsular nerves: quantification and computerised planimetry.

BACKGROUND

The exact distribution of periprostatic autonomic nerves is under debate.

OBJECTIVE

To study the topographical anatomy of autonomic nerves of the periprostatic tissue and the capsule of the prostate (CAP).

DESIGN, SETTING, AND PARTICIPANTS: Whole-mount sections of 30 prostates from patients having undergone non-nerve-sparing radical prostatectomy were investigated after immunohistochemical nerve staining. Sections from the base, the middle, and the apex were evaluated. All sections were divided into 12 sectors, which were combined into the following regions: ventral, ventrolateral, dorsolateral, and dorsal.

MEASUREMENTS

Quantification of periprostatic and capsular nerves was performed within the sectors. Computerised planimetry of the total periprostatic nerve surface area of each region was performed (Image-J software, Wayne Rasband, National Institute of Health, USA).

RESULTS AND LIMITATIONS

A total of 3514, 3860, and 3902 periprostatic nerves was counted at the base, the middle, and the apex, respectively (p=0.068). The ratio of periprostatic nerves to capsular nerves was 3.6, 2.1, and 1.9 at the base, the middle, and the apex, respectively (p=0.004). Computerised planimetry revealed a significant decrease in total nerve surface area from the base over the middle towards the apex, with 241.79, 133.64, and 89.50mm(2) (p=0.004). The percentage of total nerve surface area was highest dorsolaterally (84.1%, 75.1%, and 74.5% at base, middle, and apex, respectively) but variable: Up to 39.9% of nerve surface area was found ventrolaterally and up to 45.5% in the dorsal position. The study is limited by the fact that autonomic nerve distribution was only investigated from the base to the apex of the prostate.

CONCLUSIONS

Periprostatic nerve distribution is variable, with a high percentage of nerves in the ventrolateral and dorsal positions. Total periprostatic nerve surface area decreases from the base towards the apex due to nerves leaving the NVB branching into the prostate. This can only be discovered by nerve planimetry, not by quantification.