Understanding Anatomy of "Hilus" of Detrusor Nerves to Avoid Bladder Dysfunction After Pelvic Surgery: Demonstration Using Fetal and Adult Cadavers

Objectives: To examine the anatomy of the autonomic nerves entering the bladder using cadavers. After pelvic surgery other than cystectomy, urologists and gynecologists have great concern regarding dysuria and urinary retention postoperatively. Methods: We applied histologic observation of fetuses to findings in adults, because the topographic anatomy of nerves tends to be easier to understand in fetuses than in adults. We examined 5 fetal (2 males and 3 females) and 8 adult (5 males and 3 females) cadavers using histologic sections with hematoxylin-eosin staining and tyrosine hydroxylase immunostaining. Results: In the female adults, as well as in the male and female fetuses, the bladder detrusor nerves were concentrated in a limited area of the superodorsal surface of the bladder at the superomedial aspect of the ureterovesical junction (ie, the "nerve hilus"). Notably, in female adults, these nerves were loosely fasciculated in a fascial pedicle. However, the hilus was not as evident in male adults in contrast to the dense innervation of the seminal vesicles. The bladder detrusor nerves were characterized by a high concentration of tyrosine hydroxylase immunoreactive-negative fibers in contrast to the nerves to the seminal vesicles, which showed immunoreactive-positive fibers. Conclusions: Detrusor nerves converged at a small area between the bladder and juxtavesical ureter, and these nerves enter the bladder at the "hilus." Detrusor nerve damage near the ureterovesical junction during pelvic surgery should receive more attention to avoid postoperative bladder dysfunction.