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.