Anatomical Basis of Erectile Function after Prostatectomy: Hinata et al (page 1052) from Japan identified the cavernous nerve (CN) mesh that exists caudal or posterior to the periprostatic region between the bilateral slings of the levator ani and assessed whether nonnerve sparing radical prostatectomy could be modified. They used histological sections from elderly cadavers and investigated nerve anatomy with immunohistochemistry. The authors found that CN mesh formed a U-shaped column attached to the lateral and posterior aspects of the rhabdosphincter. Composite nitric oxide synthase (nNOS) positive nerves ran obliquely with a highly tortuous course. The anterior margin of the nerve mesh corresponded to the anterior margin of the rhabdosphincter. Left-right nerve mesh communication was seen at and near the anterior margin. Bilateral periprostatic nerves joined posterior to the urethra and immediately anterior to the recto-urethralis muscle, forming a midsagittal nerve mesh corresponding to the base of the U. The periprostatic nerves also formed a mesh or bundle that was much thinner and smaller than the U-shaped mesh along the rhabdosphincter. nNOS positive nerves consistently contained tyrosine hydroxylase positive sympathetic nerve fibers but there were few vasoactive intestinal polypeptide positive fibers. The pudendal nerve and its branches were negative for nNOS. The authors conclude that bilateral resection of the neurovascular bundle does not remove all CNs because these nerves cover the rhabdosphincter and perirectum caudal to the level of the prostatic apex. They recommend that surgeons should perform meticulous dissection without electrocautery even during nonnerve sparing radical prostatectomy to preserve maximal function postoperatively.
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