Anatomic relationships of the pelvic autonomic nervous system in female cadavers: clinical applications to pelvic surgery.

BACKGROUND: The integrity of the pelvic autonomic nervous system is essential for proper bowel, bladder, and sexual function. OBJECTIVE: The purpose of this study was to characterize the anatomic path of the pelvic autonomic system and to examine relationships to clinically useful landmarks. STUDY DESIGN: Detailed dissections were performed in 17 female cadavers. Relationships of the superior hypogastric plexus to aortic bifurcation and midpoint of sacral promontory were examined; the length and width of plexus was documented. Path and width of right and left hypogastric nerves were recorded. The origin and course of the pelvic splanchnic nerves were documented. Individual nerve tissue that contributed to the inferior hypogastric plexus was noted. Relative position of nerves to arteries, viscera, and ligaments was documented. In a subset of specimens, biopsy specimens were obtained to confirm gross findings by histologic analysis. Descriptive statistics were used for data analyses and reporting. RESULTS: In all specimens, the superior hypogastric plexus was embedded in a connective tissue sheet within the presacral space, just below the peritoneum. In 14 of 17 specimens (82.4%), the plexus formed a median distance of 21.3 mm (range, 9-40 mm) below aortic bifurcation; in the remaining specimens, it formed a median distance of 25.3 mm (range, 20.5-30 mm) above bifurcation. In 58.8% of specimens, the superior hypogastric plexus was positioned to the left of midline. The median length and width of the plexus was 39.5 (range, 11.5-68) mm and 9 (range, 2.5-15) mm, respectively. A right and left hypogastric nerve was identified in all specimens and formed a median distance of 23 mm (range, 5-32 mm) below the promontory. The median width of the hypogastric nerve was 3.5 mm (range, 3-4.5 mm) on the right and 3.5 mm (range, 2-6.5 mm) on the left. The median distance from midportion of uterosacral ligament to the closest nerve branch was 0.5 mm (range, 0-4.5 mm) on right and 0 mm (range, 0-27.5 mm) on left. In all specimens, the inferior hypogastric plexus was formed by contributions from the hypogastric nerves and branches from S3 and S4. In 47.1% of hemipelvises, S2 branches contributed to the plexus. The sacral sympathetic trunk contributed to the plexus in 16 of 34 hemipelvises where this structure was identified. The inferior hypogastric plexus formed 1-3 cm lateral to the rectum and upper third of the vagina. From this plexus, 1-3 discrete branches coursed deep to the ureter toward the bladder. A uterine branch that coursed superficial to the ureter followed the ascending branch of the uterine artery. An S4 branch was found directly attaching to lateral walls of the rectum in 53% of specimens. Pelvic splanchnic nerves merged into the inferior hypogastric plexus on the lower and medial surface of the coccygeus muscle. Histologic analysis confirmed neural tissue in all tissues that were sampled. CONCLUSION: Anatomic variability and inability to visualize the small caliber fibers that comprise the inferior hypogastric plexus grossly likely underlines the reasons that some postoperative visceral and sexual dysfunction occur in spite of careful dissection and adequate surgical technique. These findings highlight the importance of a discussion with patients about the risks that are associated with interrupting autonomic fibers during the preoperative consent.

Inferior gluteal and other nerves associated with sacrospinous ligament: a cadaver study.

BACKGROUND: Reported rates of gluteal pain after sacrospinous ligament fixation range from 12-55% in the immediate postoperative period and from 4-15% 4-6 weeks postoperatively. The source of gluteal pain often is attributed to injury to the nerve to levator ani or pudendal nerve. The inferior gluteal nerve and other sacral nerve branches have not been examined thoroughly as potential sources of gluteal pain. OBJECTIVES: The purpose of this study was to further characterize anatomy of the inferior gluteal nerve and other nerves that are associated with the sacrospinous ligament from a combined gluteal and pelvic approach and to correlate findings to sacrospinous ligament fixation. STUDY DESIGN: Dissections were performed in female cadavers that had not been embalmed with gluteal and pelvic approaches. From a pelvic perspective, the closest structure to the superior border of the sacrospinous ligament midpoint was noted, and the sacral nerves that perforated the ventral surface of coccygeus muscle were examined. From a gluteal perspective, the closest distances from ischial spine to the pudendal, inferior gluteal, posterior femoral cutaneous, and sciatic nerves were measured. In addition, the closest distance from the midpoint of sacrospinous ligament to the inferior gluteal nerve and the origin of this nerve were documented. The thickness and height of the sacrospinous ligament at its midpoint were measured. Sacral nerve branches that coursed between the sacrospinous and sacrotuberous ligaments were assessed from both a pelvic and a gluteal approach. Descriptive statistics were used for data analysis. RESULTS: Fourteen cadavers were examined. From a pelvic perspective, the closest structure to the superior border of sacrospinous ligament at its midpoint was the S3 nerve (median distance, 3 mm; range, 0-11 mm). Branches from S3 and/or S4 perforated the ventral surface of coccygeus muscles in 94% specimens. From a gluteal perspective, the closest structure to ischial spine was the pudendal nerve (median distance, 0 mm; range, 0-9 mm). Median closest distance from inferior gluteal nerve to ischial spine and to the midpoint of sacrospinous ligament was 28.5 mm (range, 6-53 mm) and 31.5 mm (range, 10-47 mm), respectively. The inferior gluteal nerve arose from dorsal surface of combined lumbosacral trunk and S1 nerves in all specimens; a contribution from S2 was noted in 46% of hemipelvises. At its midpoint, the sacrospinous ligament median thickness was 5 mm (range, 2-7 mm), and its median height was 14 mm (range, 3-22 mm). In 85% of specimens, 1 to 3 branches from S3 and/or S4 nerves pierced or coursed ventral to the sacrotuberous ligament and perforated the inferior portion of the gluteus maximus muscle. CONCLUSIONS: Damage to the inferior gluteal nerve during sacrospinous ligament fixation is an unlikely source for postoperative gluteal pain. Rather, branches from S3 and/or S4 that innervate the coccygeus muscles and those coursing between the sacrospinous and sacrotuberous ligaments to supply gluteus maximus muscles are more likely to be implicated. A thorough understanding of the complex anatomy surrounding the sacrospinous ligament, limiting depth of needle penetration into the ligament, and avoiding extension of needle exit or entry point above the upper extent of sacrospinous ligament may reduce nerve entrapment and postoperative gluteal pain.

Anterior abdominal wall nerve and vessel anatomy: clinical implications for gynecologic surgery.

OBJECTIVE: We sought to describe relationships of clinically relevant nerves and vessels of the anterior abdominal wall. STUDY DESIGN: The ilioinguinal and iliohypogastric nerves and inferior epigastric vessels were dissected in 11 unembalmed female cadavers. Distances from surface landmarks and common incision sites were recorded. Additional surface measurements were taken in 7 other specimens with and without insufflation. RESULTS: The ilioinguinal nerve emerged through the internal oblique: mean (range), 2.5 (1.1-5.1) cm medial and 2.4 (0-5.3) cm inferior to the anterior superior iliac spine (ASIS). The iliohypogastric emerged 2.5 (0-4.6) cm medial and 2.0 (0-4.6) cm inferior. Inferior epigastric vessels were 3.7 (2.6-5.5) cm from midline at the level of the ASIS and always lateral to the rectus muscles at a level 2 cm superior to the pubic symphysis. CONCLUSION: Risk of anterior abdominal wall nerve and vessel injury is minimized when lateral trocars are placed superior to the ASISs and >6 cm from midline and low transverse fascial incisions are not extended beyond the lateral borders of the rectus muscles.

Medial Thigh Anatomy in Female Cadavers: Clinical Applications to the Transobturator Midurethral Sling.

BACKGROUND: Mesh resection for refractory pain after transobturator midurethral sling may require exploration of structures different than those involved in insertion. Our objective was to describe the muscular and neurovascular anatomy of the medial thigh compartment. METHODS: Dissections were performed in unembalmed female cadavers. Relationships of medial thigh structures were evaluated relative to the midpubic arch and obturator nerve. An out-to-in transobturator tape was passed in a subset of cadavers, and its relationships to the obturator nerve and adductor muscles were examined. Descriptive statistics were used for analyses. RESULTS: Sixteen cadavers were examined. The adductor longus muscle was a median of 37 mm (26-50) from the midpubic arch with tendon length of 26 mm (12-53) and width of 16 mm (14-29). The gracilis was 21 mm (17-26) from the midpubic arch with tendon length of 28 mm (15-56) and width of 45 mm (31-68). The obturator nerve was 58 mm (51-63) from the midpubic arch with width of 5 mm (4-7). No differences between measurements in the supine and lithotomy positions were noted. The transobturator tape was 42 mm (30-47) from the midpubic arch, 36 mm (30-44) from the obturator nerve, and 20 mm (5-31) from the closest obturator nerve branch. The transobturator sling passed through the gracilis muscle in all specimens with variable passage through the adductors longus (75%) and brevis (25%). CONCLUSIONS: Familiarity with the medial thigh is essential for surgeons utilizing transobturator midurethral slings. Risks of mesh excision should be weighed against benefits before extensive thigh dissection for pain-related indications.