Anatomic Cartography of the Hypogastric Nerves and Surgical Insights for Autonomic Preservation during Radical Pelvic Procedures.

STUDY OBJECTIVE: To clarify the relationship of hypogastric nerves (HNs) with several pelvic anatomic landmarks and to assess any anatomic differences between the 2 sides of the pelvis, both in cadaveric and in vivo dissections. DESIGN: Prospective observational study. SETTING: An anatomic theater for cadaveric dissections and a university hospital for in vivo laparoscopy. PATIENTS: Five nulliparous female cadavers underwent laparotomic dissection; 10 nulliparous patients underwent laparoscopic surgery for rectosigmoid endometriosis without posterolateral parametrial infiltration. INTERVENTIONS: Measurements of the closest distance between HNs and ureters, the midsagittal plane, the midcervical plane, and uterosacral ligaments on both hemipelvises. A comparison of anatomic data of the 2 hemipelvises was conducted. MEASUREMENTS AND MAIN RESULTS: The right and left HNs were identified in all specimens, both on cadavers and in vivo dissections. A wide anatomic variability was reported. Regarding the differences between the 2 hemipelvises, we found that the right HN was significantly (p <.001) farther to the ureter (mean = 14.5 mm; range, 10-25 mm) than the left one (mean = 8.6 mm; range, 7-12 mm). The HN was closer to the midsagittal plane on the right side (mean = 14.6 mm; range, 12-17 mm) than on the left side (mean = 21.6 mm; range, 19-25 mm). The midcervical plane was found 2.7 mm (range, 2-4 mm) to the left of the midsagittal one. The right HN was found to be nonsignificantly closer to the midcervical plane and the uterosacral ligament on the right side than on the left side (p >.05). CONCLUSIONS: Despite a wide anatomic variability of position and appearance, the HNs are reproducibly identifiable using an "interfascial" technique and considering the ureters and uterosacral ligaments as anatomic landmarks.

Bone morphogenetic protein signaling regulates postnatal hair follicle differentiation and cycling.

Hair follicle morphogenesis and cycling were examined in transgenic mice that overexpress the bone morphogenetic protein (BMP) inhibitor Noggin under the control of the neuron-specific enolase promoter. The Noggin transgene was misexpressed in the proximal portion of the hair follicle, primarily the matrix cells, apart from the usual expression in neurons. Transgene expression appeared only after induction of both the primary (tylotrich) and secondary (nontylotrich) pelage hair follicles had already occurred, thus allowing examination of the role of BMP signaling in follicles that had been induced normally in the presence of BMPs. The overexpression of Noggin in these animals resulted in a dramatic loss of hair postnatally. There was an apparently normal, but shortened period of postnatal hair follicle morphogenesis, followed by premature initiation of hair follicle cycling via entry into the first catagen transformation. This resulted in a complete loss of hair shafts from the nontylotrich hair follicles in these mice while the tylotrich hair follicles were normal. The onset of anagen of the first postnatal hair follicle cycle was also accelerated in the transgenic mice. Our results show that BMP signaling is specifically required for proper proliferation and differentiation during late morphogenesis of nontylotrich hair follicles and that inhibition of this signaling pathway may be one of the triggers for the onset of catagen when the follicles are in anagen and the onset of anagen when the follicles are in telogen. Ectopic sebocyte differentiation was another hallmark of the phenotype of these transgenic mice suggesting that BMP signaling may be an important determinant of lineage selection by common progenitor cells in the skin. BMPs likely promote a hair follicle-type differentiation pathway of keratinocytes while suppressing the sebaceous differentiation pathway of skin epithelium.