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Purpose: Retrospective reviews suggest that the functional outcomes of surgery of the urogenital sinus have often been unsatisfactory and to our knowledge the long-term results of newer surgical techniques have yet to be evaluated. A precise understanding of pelvic fetal neuroanatomy is germane for optimizing surgical correction of the urogenital sinus., Materials and Methods: The pelves of 10 human female fetuses were serially sectioned. Masson's trichrome staining and immunochemistry for the neuronal marker S100 (Dako Corp., Carpinteria, California) along with anatomical computer reconstruction allowed 3-dimensional analysis of the nerves in relation to the pelvic structures as an animated motion picture., Results: Two types of neuronal structures were identified. 1) A dense perivisceral foil of branching nerves closely surrounded the pelvic organs. The localization of most nerves was on the external faces of the viscera with a limited fraction in the rectovaginal and urethrovaginal septa. This innervation was from the anterior cephalad periurethral area to the posterior caudal perirectal area. 2) A significant amount of nerves surrounded the cephalad urethra on its anterior and posterior faces., Conclusions: Based on these anatomical data during surgical repair of a urogenital sinus we would advocate minimal mobilization of the lateral faces of the vagina, avoiding dissection of the proximal urethra above the pubic bone and electing a vaginal flap in severe cases.

Purpose: We investigated the fetal development of the smooth (lissosphincter) and striated (rhabdosphincter) female external urinary sphincter. Growth and organization of the muscle fibers around the urethra and morphological modifications due to the development of the vagina were analyzed in detail., Materials and Methods: A total of 28 human female fetal specimens were investigated in an anatomical and histological study. The sections were processed according to plastination technology. This technique allows examination of structures and organs of the small pelvis with minimal artifacts in all 3 planes., Results: At gestational week 9 the primordium of the external urethral sphincter complex was observed extending along the anterior aspect of the urogenital sinus, before the development of the primitive urethra and the vaginal primordium. From 15 weeks of gestation the lissosphincter and rhabdosphincter could be identified and clearly distinguished. After 20 weeks of gestation both elements acquired an omega-shaped configuration with a narrow posterior connective tissue raphe that was constantly present, fixing both components to the ventral vaginal wall. Both muscles were mainly located in the middle third of the urethra. In the proximal third of the urethra growth of the vagina led to disappearance of the striated muscle fibers of the rhabdosphincter, whereas the lissosphincter seemed to intermingle with the internal layer of the detrusor musculature of the bladder., Conclusions: The important morphological characteristics of the female adult rhabdosphincter and lissosphincter (omega-shaped configuration, presence of a narrow connective tissue raphe posteriorly and maximum thickness in the middle third of the urethra) are already evident early in fetal development and do not evolve during postnatal growth or by the influence of sex hormones.

Purpose: The neuroanatomy of the female lower urogenital tract remains controversial. We defined the topographical anatomy and differential immunohistochemical characteristics of the dorsal nerve of the clitoris, the cavernous nerve and the nerves innervating the female urethral sphincter complex., Materials and Methods: A total of 16 normal female human pelvic specimens at 14 to 34 weeks of gestation were studied by immunohistochemical techniques. Serial sections were stained with antibodies raised against the neuronal markers S-100 and neuronal nitric oxide synthase (nNOS), vesicular acetylcholine transporter, calcitonin gene-related peptide and substance P. The serial sections were computer reconstructed into 3-dimensional images., Results: Under the pubic arch at the hilum of the clitoral bodies the branches of the cavernous nerves joined the clitoral dorsal nerve to transform its immunoreactivity to nNOS positive. The cavernous nerves originated from the vaginal nervous plexus occupying the 2 and 10 o'clock positions on the anterolateral vagina and they traveled at the 5 and 7 o'clock positions along the urethra. The urethral sphincter complex was innervated by nNOS immunoreactive and nonimmunoreactive nerve fibers arising from the vaginal nervous plexus and pudendal nerve, respectively., Conclusions: The dorsal nerve of the clitoris receives nNOS positive branches from the cavernous nerve as a possible redundant mechanism for clitoral erectile function. The urethral sphincter complex has dual innervation, which pierces into the urethral sphincter complex at different locations. The study of the neuroanatomy of the female lower urogenital tract is germane to the strategic design of female reconstructive surgery.

Purpose: In females abnormal urogenital virilization can occur secondary to prenatal exposure to exogenous or endogenous androgens. We studied the effects of different doses of prenatal androgens on urogenital sinus development and the location of the vaginal confluence in a mouse model., Materials and Methods: Timed pregnant C57/6 mice were exposed to 2, 5 and 10 mg testosterone propionate on gestational days 14 through 18. On gestational day 19 the genital tubercles and internal genitalia were examined grossly and histologically for the presence of virilization. Three-dimensional computer reconstruction was done and plastic cast injection molds of the urogenital sinus were made in select specimens., Results: Microscopic analysis confirmed the spectrum of virilization, which occurred in 98% of testosterone propionate treated female fetuses. Plastic cast injection showed that affected females had a longer urogenital sinus, more proximal confluence and shorter vagina in a dose dependent manner. Histological sections and 3-dimensional reconstruction revealed that the bladder neck moved proximal under the pubic bone, also in a dose dependent manner., Conclusions: Prenatal exposure to increasing levels of androgen causes urogenital sinus elongation in a female mouse fetus. In the mouse model the confluence area moves proximally together with the bladder neck in a dose dependent manner.

Purpose: Although a dual origin of the vagina has been popularized, other theories support a müllerian or wolffian duct origin or various combinations of these structures and the urogenital sinus. Uroplakins are specialized membrane proteins of the urothelial plaque, constituting the asymmetrical unit membrane of the bladder, and represent specific molecular markers of urothelial differentiation. We hypothesize that the epithelium of the dorsal wall of the urogenital sinus is involved in the formation of the sinovaginal bulbs and will express uroplakins. In addition, localization of the androgen receptor and its temporal expression during development may in part explain the varied effects of androgens on the lower female genital tract in congenital adrenal hyperplasia., Materials and Methods: Lower genitourinary tracts from 4 human female fetuses (9 to 18 weeks) were serially sagittally sectioned. Representative sections were stained with hematoxylin and eosin, rabbit antibodies against panuroplakin and antibodies to the androgen receptor., Results: At 9 weeks of gestation the urogenital sinus showed evidence of evagination and the formation of the sinovaginal bulbs. The urothelium of the entire urogenital sinus expressed uroplakins including the region of the dorsal wall involved in evagination and formation of the sinovaginal bulbs. The müllerian ducts were in direct contact with the area of urogenital sinus evagination but were not in continuity with the sinus. Androgen receptors were expressed in the epithelium and the stroma of the urogenital sinus, sinovaginal bulbs, and müllerian and wolffian ducts. By 14 weeks androgen receptor expression was almost absent in the urothelium of the urogenital sinus, and the epithelium and surrounding stroma of the lower vagina and müllerian ducts., Conclusions: The area of evagination of the urogenital sinus expresses uroplakins, is involved in the formation of the sinovaginal bulbs and further substantiates the urogenital sinus origin of the lower vagina. Since testosterone inhibits formation of the lower vagina, the timing of exposure to systemic testosterone in congenital adrenal hyperplasia will determine the phenotypic appearance of the external genitalia and effect of testosterone on the development of the lower genital tract. If exposure to testosterone occurs after 12 weeks only clitoromegaly occurs. Androgen receptor is absent in the urogenital sinus urothelium, vaginal epithelium and müllerian ducts by 14 weeks, suggesting that these tissues become androgen insensitive and vaginal development will proceed normally after that critical time.

Uterus didelphys with double vagina and hemi-vaginal atresia is a rare syndrome of congenital anomalies. A 17-year-old girl had a right blind-ending ectopic ureter, the proximal end of which communicated with the ipsilateral uterine cervix of uterus didelphys. The patient presented with vaginal urinary incontinence after incision of the vaginal wall for right hemi-hematocolpometra. Following various examinations, the ipsilateral kidney was found to be absent. The ectopic ureter and communicating duct were resected, and the fistula was closed. The genesis of malformation of the female genitalia and urinary tract resulting in such a unique communication is discussed. The importance of preoperative meticulous examinations, including cysto-genitography, pelvic magnetic resonance imaging and panendoscopy with the patient under anesthesia, is emphasized.

A new embryologic classification is proposed to explain the association of unilateral renal agenesis with abnormalities of the female reproductive tract. An awareness of the syndrome of combined müllerian and mesonephric duct abnormalities may permit accurate anatomic diagnosis and spare patients needless surgical exploration.