Mills Ch35 Prostate

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CHAPTER 35:  Prostate

muscle (mid to base). Moreover, the anterior fibromuscular stroma also contains blood vessels that supply/drain the ante- rior prostate throughout its extent. Due to the complex tissue composition of the anterior and anterolateral prostates and lack of a definitive border, the task of separating prostatic from extraprostatic tissue can be challenging in this region. Extraprostatic Tissues, Prostatic Innervation, and Vascular Supply In vivo, the tissue immediately anterior to the prostate is the dorsal venous or vascular complex, a series of veins and arter- ies set in fibroadipose tissue that runs over the anterior pros- tate and continues distally to supply/drain the penis (22). At the time of radical prostatectomy, the dorsal vascular complex is ligated and then divided, with a portion of the blood vessels and fibroadipose tissue remaining adherent to the prostate specimen. These may be identified as the anterior extrapros- tatic tissue from apex through mid gland. The most proxi- mal (basal) two to three sections typically reveal medium- to large-sized smooth muscle bundles admixed with adipose tissue (Fig. 35.16). These fibers are morphologically identi- cal to those of the detrusor muscle and possibly represent the inferior border of the bladder neck (23). Over the medial half of the posterior (rectal) surface of the prostate, the thickness of the capsule is increased by its fusion to Denonvilliers’ fascia (Figs. 35.17 and 35.18), a thin, compact collagenous membrane whose smooth

FIGURE 35.16  Prostate at mid to base of the gland—anterior extra- prostatic space displays numerous medium- to large-sized discrete (detrusor-like) muscle bundles ( DLM ) admixed with adipose tissue, which merge with the anterior fibromuscular stroma ( AFMS ).

FIGURE 35.17  Distribution of nerve branches to the prostate, right posterolateral view. Nerves within the neurovascular bundle ( NB ) ( red ) branch to supply the prostate ( brown ) in a large superior pedicle ( SP ) at the prostate base and a small inferior pedicle ( IP ) at the prostate apex. Nerve branches ( orange ) leave the lateral pelvic fascia (not shown) to travel in Denonvilliers’ fascia ( DF ), which has been cut away from the right half of the prostate. Nerve branches from the superior pedicle fan out over a large area. A small horizontal subdivision ( H-N ) crosses the base to midline; a large vertical subdivision ( V-N ) fans out extensively over the prostate surface as far dis- tally as mid prostate. Branches con- tinue their course within the prostate after penetration into the capsule within a large nerve penetration area ( green ). A small inferior pedicle has a limited ramification and nerve penetra- tion area ( green ). LPF , lateral pelvic fascia.