Anatomic Study of Periprostatic Nerve Distribution: Immunohistochemical Differentiation of Parasympathetic and Sympathetic Nerve Fibres

Many authors advocate a high anterior incision during nerve-sparing radical prostatectomy (RP) to improve potency results. Despite a growing number of studies describing autonomic nerves in the ventrolateral position of the prostate, little is known about their quality and their role in erectile function. The intention of this study was a detailed characterisation of the topographic distribution of periprostatic nerves, including immunohistochemical differentiation of proerectile parasympathetic from sympathetic nerves. A total of 228 whole-mount sections of 38 prostates (base, middle, apex) from patients following non–nerve-sparing laparoscopic RP were analysed. Immunohistochemical analysis was performed using antibodies against tyrosine hydroxylase for sympathetic and vesicular acetylcholine transporter for parasympathetic nerve fibre staining. Quantification of periprostatic parasympathetic and sympathetic nerves was performed after defining prostatic regions via a digital grid. Differences among three independent variables were tested with the nonparametric Kruskal-Wallis test. The total number of parasympathetic nerves did not decrease from the base to the apex. They were dispersed at the base and mainly located dorsolaterally at the apex, with 14.6% above the horizontal line at the base and only 1.5% at the apex. In contrast, the total number of sympathetic nerves decreased significantly from base to apex, with a constant proportion of ventrolateral nerves between 9% (base) and 6.2% (apex). This anatomic study is limited by the investigation of postprostatectomy specimens and the lack of functional results. Despite the presence of ventrolateral periprostatic nerves, only a minority of these nerves seems to have a parasympathetic proerectile quality. The arguments in favour of a high anterior incision during nerve-sparing prostatectomy might not only include preserved nerves but also other factors, such as reduced traction or improved anatomic support of the neural structures.