Somatic and autonomic nerve density and distribution within the clitoris: an immunohistochemical study in adult female cadavers.

INTRODUCTION AND HYPOTHESIS: Knowledge of clitoral neuroanatomy is critical to vulvar surgery. We sought to characterize the density and distribution of autonomic and somatic nerves supplying the clitoris. METHODS: Pelvic tissue harvested from female cadavers was sectioned axially at three anatomic levels: the proximal aspect of the clitoral body (CB), the distal CB, and the glans. The CB, glans, and the surrounding connective tissue (dorsal, lateral, and ventral) were outlined microscopically. An area containing large nerve bundles dorsal to the CB, referred to as the dorsal nerve subregion, was analyzed separately. Double-immunofluorescent staining for beta III tubulin (ßIIIT), a global axonal marker, and myelin basic protein (MBP), a myelinated nerve marker, was performed. Threshold-based automatic image-segmentation distinguished stained areas. Autonomic and somatic density were calculated as percentage of tissue stained with ßIIIT alone, and ßIIIT and MBP respectively. Comparisons were made using nonparametric Friedman tests. RESULTS: Seven cadavers, aged 22-81, were examined. Somatic (mean 4.42%, SD ± 1.97) and autonomic (2.14% ± 2.42) nerve density was highest in the dorsal nerve subregion and dorsal region at the distal CB level. Compared with the CB, somatic density was higher in proximal (0.05% ± 0.03 vs 1.27% ± 0.69, p = 0.03) and distal (0.29% ± 0.25 vs 1.09% ± 0.41, p = 0.05) dorsal regions. Somatic density was greater in the glans than in the surrounding lateral (0.78% ± 0.47 vs 0.43% ± 0.23, p = 0.03) and ventral (0.78% ± 0.47 vs 0.52% ± 0.2, p = 0.03) regions. Autonomic density was greater than somatic in all areas, except for the dorsal nerve subregion. CONCLUSIONS: Somatic and autonomic nerve density were greatest in a well-defined region dorsal to the CB. Surgical preservation of this region is critical for maintaining nerve supply to the clitoris.

Somatic and autonomic nerve density of the urethra, periurethral tissue, and anterior vaginal wall: an immunohistochemical study in adult female cadavers.

INTRODUCTION AND HYPOTHESIS: Retropubic procedures may disrupt nerves supplying the pelvic viscera; however, knowledge of pelvic neuroanatomy is limited. We sought to characterize somatic and autonomic nerve density within the urethra, periurethral tissue, and anterior vagina. METHODS: Axial sections were obtained from pelvic tissue harvested from female cadavers ≤24 h from death at three anatomical levels: the midurethra, proximal urethra, and upper trigone. Periurethral/perivesical tissue was divided into medial and lateral sections, and the anterior vagina into middle, medial, and lateral sections. Double immunofluorescent staining for beta III tubulin (ßIIIT), a global axonal marker, and myelin basic protein (MBP), a myelinated nerve marker, was performed. Threshold-based automatic image segmentation distinguished stained areas. Autonomic and somatic density were calculated as percentage of tissue stained with ßIIIT alone, and with ßIIIT and MBP respectively. Statistical comparisons were made using nonparametric Friedman tests. RESULTS: Six cadavers, aged 22-73, were examined. Overall, autonomic nerve density was highest at the midurethral level in the lateral and middle anterior vagina. Somatic density was highest in the external urethral sphincter (midurethra mean 0.15%, SD ±0.11; proximal urethra 0.19%, SD ±0.19). Comparison of annotated sections revealed significant differences in autonomic density among the lateral, medial, and middle vagina at the midurethra level (0.71%, SD ±0.48 vs 0.60%, SD ±0.48 vs 0.70%, SD ±0.63, p=0.03). Autonomic density was greater than somatic density in all sections. CONCLUSIONS: Autonomic and somatic nerves are diffusely distributed throughout the periurethral tissue and anterior vagina, with few significant differences in nerve density among sections analyzed. Minimizing tissue disruption near urethral skeletal muscle critical for urinary continence may prevent adverse postoperative urinary symptoms.

Anatomic relationships of the clitoral body, bulbs of the vestibule, and urethra.

BACKGROUND: Although recent studies have enhanced our understanding of the anatomy of the clitoris and its somatic innervation, less emphasis has been placed on the anatomic relationships of the clitoris to its surrounding structures. OBJECTIVE: This study aimed to further characterize the gross and histologic relationships of the clitoris, vestibular bulbs, and urethra. STUDY DESIGN: Detailed dissections were performed in 30 unembalmed female cadavers. In 23 specimens, gross dissections were performed, and relationships of the clitoris, vestibular bulbs, and urethra were annotated. Histologic evaluation was performed in 7 specimens, in which tissues were harvested within 24 hours from death. Descriptive statistics were used for data analyses. RESULTS: The clitoral body consisted of 2 components, the proximal body and the distal body. The distal body was oriented ≤90° from the proximal body, forming an outer and inner angle at the inflection point. A "septumlike" arrangement of fibroconnective and vascular tissues was noted between the inner angle of the clitoral body and the urethra. Neurovascular bundles coursed laterally along the clitoral body and the surfaces of the crura and vestibular bulbs. The vestibular bulbs approached each other over the ventral surface of the urethra, at the commissure of the vestibular bulbs. Each bulb was separated by fibrous tissue and did not merge along the midline. The vestibular bulbs approximated the clitoral body, but the erectile tissue of the vestibular bulbs was separated from the corpora cavernosa of the clitoral body by the tunica albuginea. The erectile tissue of the vestibular bulbs abutted the ventrolateral walls of the urethra but was separated from the urethral mucosa by an indiscrete layer of erectilelike tissue with dense stroma. CONCLUSION: This study provided gross and histological confirmation of the relationships of the clitoris, vestibular bulbs, and urethra. Detailed knowledge of the anatomy of the clitoris is crucial for reducing surgical complications associated with periclitoral and distal urethral procedures, which may adversely affect sexual arousal and sexual function.

Recommended standardized anatomic terminology of the posterior female pelvis and vulva based on a structured medical literature review.

BACKGROUND: Anatomic terminology in both written and verbal forms has been shown to be inaccurate and imprecise. OBJECTIVE: Here, we aimed to (1) review published anatomic terminology as it relates to the posterior female pelvis, posterior vagina, and vulva; (2) compare these terms to "Terminologia Anatomica," the internationally standardized terminology; and (3) compile standardized anatomic terms for improved communication and understanding. STUDY DESIGN: From inception of the study to April 6, 2018, MEDLINE database was used to search for 40 terms relevant to the posterior female pelvis and vulvar anatomy. Furthermore, 11 investigators reviewed identified abstracts and selected those reporting on posterior female pelvic and vulvar anatomy for full-text review. In addition, 11 textbook chapters were included in the study. Definitions of all pertinent anatomic terms were extracted for review. RESULTS: Overall, 486 anatomic terms were identified describing the vulva and posterior female pelvic anatomy, including the posterior vagina. "Terminologia Anatomica" has previously accepted 186 of these terms. Based on this literature review, we proposed the adoption of 11 new standardized anatomic terms, including 6 regional terms (anal sphincter complex, anorectum, genital-crural fold, interlabial sulcus, posterior vaginal compartment, and sacrospinous-coccygeus complex), 4 structural terms (greater vestibular duct, anal cushions, nerve to the levator ani, and labial fat pad), and 1 anatomic space (deep postanal space). In addition, the currently accepted term rectovaginal fascia or septum was identified as controversial and requires further research and definition before continued acceptance or rejection in medical communication. CONCLUSION: This study highlighted the variability in the anatomic nomenclature used in describing the posterior female pelvis and vulva. Therefore, we recommended the use of standardized terminology to improve communication and education across medical and anatomic disciplines.

Posterior Vaginal Compartment Anatomy: Implications for Surgical Repair.

OBJECTIVES: To examine the gross and histologic anatomy of the proximal, mid, and distal posterior vaginal compartment and discuss implications for surgical repair. STUDY DESIGN: In this cadaver study, pelvic organs were resected en bloc, immersed in formalin solution, and transected in the mid sagittal plane. Measured distances included: posterior vaginal wall length, cervicovaginal junction or vaginal cuff to posterior peritoneal reflection, peritoneal reflection to proximal edge (apex) of perineal body, and perineal body apex to hymenal remnant (height). The posterior vaginal wall was divided into 3 segments along the midsagittal plane and submitted in whole tissue blocks for staining. Histologic analysis included that of 2 young nulliparous women whose tissue was harvested within 12 hours of death. RESULTS: Eleven cadavers were examined. Median (interquartile range [IQR]) posterior vaginal length was 7.6 (2.2) cm. The peritoneum attached to the posterior vaginal wall a median (IQR) of 1.3 cm (0.5 cm) distal to the cervicovaginal junction (n = 8). The rectovaginal space, spanning from the peritoneal reflection to perineal body apex, had a median (IQR) length of 4.7 cm (2.1 cm). Microscopic examination of the mid segment revealed a layer of loose fibroadipose tissue between the vaginal/rectal walls, with no distinct dense fibroconnective tissue layer. The median (IQR) perineal body height was 2.3 cm (1.2 cm). No discrete fibrous capsule was seen surrounding the external anal sphincter muscle. CONCLUSIONS: These findings support evidence showing absence of a rectovaginal fascia. The anal sphincter lacks a fibrous capsule, which is important during closure of third-/fourth-degree obstetric lacerations.

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.

Standardized terminology of apical structures in the female pelvis based on a structured medical literature review.

The objectives of this study were to review the published literature and selected textbooks, to compare existing usage to that in Terminologia Anatomica, and to compile standardized anatomic nomenclature for the apical structures of the female pelvis. MEDLINE was searched from inception until May 30, 2017, based on 33 search terms generated by group consensus. Resulting abstracts were screened by 11 reviewers to identify pertinent studies reporting on apical female pelvic anatomy. Following additional focused screening for rarer terms and selective representative random sampling of the literature for common terms, accepted full-text manuscripts and relevant textbook chapters were extracted for anatomic terms related to apical structures. From an initial total of 55,448 abstracts, 193 eligible studies were identified for extraction, to which 14 chapters from 9 textbooks were added. In all, 293 separate structural terms were identified, of which 184 had Terminologia Anatomica-accepted terms. Inclusion of several widely used regional terms (vaginal apex, adnexa, cervico-vaginal junction, uretero-vesical junction, and apical segment), structural terms (vesicouterine ligament, paracolpium, mesoteres, mesoureter, ovarian venous plexus, and artery to the round ligament) and spaces (vesicocervical, vesicovaginal, presacral, and pararectal) not included in Terminologia Anatomica is proposed. Furthermore, 2 controversial terms (lower uterine segment and supravaginal septum) were identified that require additional research to support or refute continued use in medical communication. This study confirms and identifies inconsistencies and gaps in the nomenclature of apical structures of the female pelvis. Standardized terminology should be used when describing apical female pelvic structures to facilitate communication and to promote consistency among multiple academic, clinical, and surgical disciplines.

Anatomy, histology, and nerve density of clitoris and associated structures: clinical applications to vulvar surgery.

BACKGROUND: A precise understanding of structures comprising the female external genitalia is essential in obstetric and gynecologic practice. OBJECTIVE: To further characterize the anatomy, histology, and nerve density of the clitoris and associated structures, and to provide clinical correlations to vulvar surgery. MATERIALS AND METHODS: Unembalmed female cadavers were examined. The length and width of the body, glans, and crura of the clitoris were measured. Distances from the glans to the urethra and from the dorsal surface of the clitoral body to the mid pubic arch were recorded. The path of the dorsal nerve of the clitoris was examined, and the nerve width was measured as it emerged from the lateral surface of crura and at the distal clitoral body. Distances from where the dorsal nerve emerged from the perineal membrane to the posterior surface of the membrane and to mid pubic arch were measured. Connective tissue layers associated with the clitoris were examined. Tissue was harvested from additional unembalmed cadavers, and nerve density of the labia minora, glans, and clitoral body were analyzed. Histological examination was performed on vulvar structures to clarify tissue composition. Descriptive statistics were used for data analyses. RESULTS: A total of 27 cadavers (aged 48-96 years) were examined, 22 grossly and 5 histologically. The median length and width of clitoral body were 29 mm (range, 13-59 mm) and 9 mm (range, 5-14 mm), respectively. The glans was 8 mm (range, 5-12 mm) long and 4 mm (range, 3-10 mm) wide. The length of the crura was 50 mm (range, 25-68 mm), and the width at the anterior portion was 9 mm (range, 2-13 mm). The closest distance from the glans to the urethra was 25 mm (range, 14-37 mm) and from the clitoral body to the mid pubic arch was 29 mm (range, 14-46 mm). The widths of the dorsal nerve at the lateral crura and at the distal clitoral body were 3 mm (range, 2-4 mm) and 1 mm (range, 1-2 mm), respectively. The distance from the dorsal nerve as it emerged from the perineal membrane to the mid pubic arch was 34 mm (range, 20-48 mm) and to the posterior surface of the membrane was 20 mm (range, 8-31 mm). The dorsal nerve and artery of the clitoris coursed adjacent to the medial surface of the inferior pubic ramus surrounded by a dense fibrous capsule adherent to the periosteum. The nerve and artery then coursed deep to dense connective tissue layers, which were contiguous with the suspensory ligament and fascia of the clitoris. Histologic examination revealed the presence of erectile tissue in the clitoral body, crura, and vestibular bulbs, but such tissue was absent in the glans and labia minora. Nerve density analysis revealed statistically significant greater density in the dorsal compared with ventral half of the clitoral body. Although not statistically significant, there was increased nerve density in the distal compared to the proximal half of the labia minora. CONCLUSION: Precise knowledge of clitoral anatomy and associated neurovascular structures is essential to safely complete partial vulvectomies, clitoral and vulvar reconstructive procedures, anti-incontinence surgeries, and repair of obstetric lacerations. Understanding the range of anatomic variations and awareness of the areas of increased nerve density is important during counseling and surgical planning. Although the dorsal nerve of the clitoris courses deep to dense connective tissue layers, inadvertent injury may occur in the setting of deep dissection or suture placement. The dorsal nerve seems most vulnerable with surgical entry or lacerations that extend from the midline of the prepuce to the inferior pubic rami.

Gross and Histologic Anatomy of the Pelvic Ureter: Clinical Applications to Pelvic Surgery.

OBJECTIVE: To further evaluate relationships of the pelvic ureter to clinically relevant structures and to characterize the anatomy, histology, and nerve density of the distal ureter. METHODS: In this observational cadaveric study, 35 female cadavers were examined, 30 by gross dissections and five microscopically. Ureter length and segments of pelvic ureter were measured. Closest distances between the ureter and clinically relevant points were recorded. The distal pelvic ureter and surrounding parametrium were evaluated microscopically. Nerve density was analyzed using automated quantification of peripheral nerve immunostaining. Average measurements of nerve density in the anterior and posterior quadrants surrounding the ureter were statistically compared using a two-tailed t test. Descriptive statistics were used for analyses with distances reported as mean±SD (range). RESULTS: Gross dissections revealed ureter length of 26.3±1.4 (range 24-29) cm (right), 27.6±1.6 (25-30.5) cm (left). Lengths of ureter from pelvic brim to uterine artery crossover were 8.2±1.9 (4.4-11.5) cm (right), 8.5±1.5 (4.5-11.5) cm (left) and from crossover to bladder wall 3.3±0.7 (2.4-5.8) cm (right), 3.2±0.4 (2.6-4.1) cm (left). Intramural ureter length was 1.5±0.3 (1-2.2) cm (right) and 1.7±1.2 (0.8-2.5) cm (left). Distances from the ureter to uterine isthmus: median 1.7 (range 1-3.0) cm (right) and 1.7 (1.0-2.9) cm (left); lateral anterior vaginal fornix 1.5 (1.0-3.1) cm (right) and 1.7 (0.8-3.2) cm (left); lateral vaginal apex 1.3 (1.0-2.6) cm (right) and 1.2 (1.1-2.2) cm (left) were recorded. Microscopy demonstrated denser fibrovascularity posteromedial to the ureter. Peripheral nerve immunostaining revealed greater nerve density posterior to the distal ureter. CONCLUSION: Proximity of the ureter to the uterine isthmus and lateral anterior vagina mandates careful surgical technique and identification. The intricacy of tissue surrounding the distal ureter within the parametrium and the increased nerve density along the posterior distal ureter emphasizes the importance of avoiding extensive ureterolysis in this region.

Long-Term Outcomes After Overlapping Sphincteroplasty for Cloacal-Like Deformities.

OBJECTIVE: The aim of this study was to report subjective, long-term outcomes and describe patient demographics, presenting symptoms, perioperative management, and complications after overlapping sphincteroplasty repair for chronic fourth-degree lacerations (cloacal-like deformities). METHODS: In this retrospective study, hospital records were reviewed for women who underwent overlapping anal sphincteroplasty for a cloacal-like deformity of the perineum at a single institution from 1996 to 2013. Details including patient demographics, presenting symptoms, perioperative management, and complications were abstracted from the medical record. As a follow-up, subjects were contacted by telephone and were administered the validated Modified Manchester Health Questionnaire to assess anal continence status and anal incontinence-related quality of life since the time of surgery. RESULTS: Of 57 women who underwent an anal sphincteroplasty within the study period, 29 met inclusion criteria. Median parity was 3 (range, 1-7) and 24.5% reported a history of forceps or vacuum-assisted vaginal delivery. Presenting symptoms included fecal incontinence (58.6%), flatal incontinence (41%), sexual dysfunction (20.7%), and poor body self-image (3.4%). Thirteen (45%) women could be contacted by telephone and all agreed to participate. Overall, 46.2% of the 13 women who completed the Modified Manchester Health Questionnaire reported some form anal of incontinence, whereas 53.8% reported complete continence at a mean follow-up of 7.0 ± 3.6 years. Perioperative morbidity was uncommon, and postoperative antibiotics were used in 75.9% of cases for a median duration of 8.8 ± 3.3 days. CONCLUSIONS: Perioperative morbidity after overlapping sphincteroplasty for cloacal-like deformities after obstetrical injury is rare. Although long-term complete anal continence may be difficult to achieve in all cases, good quality of life measures and low symptom severity were noted at a mean interval of 7 years after surgery.

Gross and histologic relationships of the retropubic urethra to lateral pelvic sidewall and anterior vaginal wall in female cadavers: clinical applications to retropubic surgery.

BACKGROUND: Knowledge of the retropubic space anatomy is essential for safe entry and surgical applications within this space. OBJECTIVE: The objectives of this study were to examine the gross and histologic anatomy of the retropubic urethra, paraurethral tissue, and urethrovaginal space and to correlate findings to retropubic procedures. STUDY DESIGN: Anatomic relationships of the retropubic urethra were examined grossly in unembalmed female cadavers. Measured distances included: lateral urethral wall to arcus tendineus fascia pelvis at the level of urethrovesical junction and at 1 cm distal. Other measurements included retropubic urethral length and distances from internal urethral opening to each ureteric orifice. Microscopic examination was performed at the same levels examined grossly in separate nulliparous specimens. Descriptive statistics were used for data analyses. RESULTS: In all, 25 cadavers were examined grossly. Median distance from lateral urethral wall to arcus tendineus fascia pelvis at the level of urethrovesical junction was 25 mm (range, 13-38 mm). At 1 cm distal, the median distance from aforementioned structures was 14 mm (10-26 mm). Median length of the retropubic urethra was 23 mm (range 15-30 mm). Four nulliparous specimens, ages 12 weeks, and 34, 47, and 52 years, were examined histologically. No histologic evidence of a discrete fascial layer between bladder/urethra and anterior vagina was noted at any level examined. Tissue between the urethra and the pelvic sidewall skeletal muscle was composed of dense fibrous tissue, smooth muscle bundles, scant adipose tissue, blood vessels, and nerves. The smooth muscle fibers of the vaginal muscularis interdigitated with skeletal muscle fibers in the pelvic sidewall at both levels examined. No histologic evidence of "pubourethral ligaments" within the paraurethral tissue was noticed. CONCLUSION: A 2-cm "zone of safety" exists between the urethra and arcus tendineus fascia pelvis at the urethrovesical junction level. Suture or graft placement within this region should minimize injury to the urethra, pelvic sidewall muscles, and bladder. Knowledge that the shortest length of retropubic urethra was 1.5 cm and shortest urethra to arcus tendineus fascia pelvis distance was 1 cm highlights the importance of maintaining dissection and trocar entry site close to pubic bone to avoid bladder and/or urethral injury. Histologic analysis of paraurethral tissue supports the nonexistence of pubourethral ligaments.

Recommended standardized terminology of the anterior female pelvis based on a structured medical literature review.

BACKGROUND: The use of imprecise and inaccurate terms leads to confusion amongst anatomists and medical professionals. OBJECTIVE: We sought to create recommended standardized terminology to describe anatomic structures of the anterior female pelvis based on a structured review of published literature and selected text books. STUDY DESIGN: We searched MEDLINE from its inception until May 2, 2016, using 11 medical subject heading terms to identify studies reporting on anterior female pelvic anatomy; any study type published in English was accepted. Nine textbooks were also included. We screened 12,264 abstracts, identifying 200 eligible studies along with 13 textbook chapters from which we extracted all pertinent anatomic terms. RESULTS: In all, 67 unique structures in the anterior female pelvis were identified. A total of 59 of these have been previously recognized with accepted terms in Terminologia Anatomica, the international standard on anatomical terminology. We also identified and propose the adoption of 4 anatomic regional terms (lateral vaginal wall, pelvic sidewall, pelvic bones, and anterior compartment), and 2 structural terms not included in Terminologia Anatomica (vaginal sulcus and levator hiatus). In addition, we identified 2 controversial terms (pubourethral ligament and Grafenberg spot) that require additional research and consensus from the greater medical and scientific community prior to adoption or rejection of these terms. CONCLUSION: We propose standardized terminology that should be used when discussing anatomic structures in the anterior female pelvis to help improve communication among researchers, clinicians, and surgeons.

First sacral nerve and anterior longitudinal ligament anatomy: clinical applications during sacrocolpopexy.

BACKGROUND: The recommended location of graft attachment during sacrocolpopexy is at or below the sacral promontory on the anterior surface of the first sacral vertebra. Graft fixation below the sacral promontory may potentially involve the first sacral nerve. OBJECTIVE: The objectives of this study were to examine the anatomy of the right first sacral nerve relative to the midpoint of the sacral promontory and to evaluate the thickness and ultrastructural composition of the anterior longitudinal ligament at the sacral promontory level. STUDY DESIGN: Anatomic relationships were examined in 18 female cadavers (8 unembalmed and 10 embalmed). The midpoint of the sacral promontory was used as reference for all measurements. The most medial and superior point on the ventral surface of the first sacral foramen was used as a marker for the closest point at which the first sacral nerve could emerge. Distances from midpoint of sacral promontory and the midsacrum to the most medial and superior point of the first sacral foramen were recorded. The right first sacral nerve was dissected and its relationship to the presacral space was noted. The anterior longitudinal ligament thickness was examined at the sacral promontory level in the midsagittal plane. The ultrastructural composition of the ligament was evaluated using transmission electron microscopy. Height of fifth lumbar to first sacral disc was also recorded. Descriptive statistics were used for data analyses. RESULTS: Median age of specimens was 78 years and median body mass index was 20.1 kg/m2. Median vertical distance from midpoint of sacral promontory to the level of the most medial and superior point of the first sacral foramen was 26 (range 22-37) mm. Median horizontal distance from the midsacrum to the first sacral foramen was 19 (range 13-23) mm. In all specimens, the first sacral nerve was located just behind the layer of parietal fascia covering the piriformis muscle, and thus, outside the presacral space. Median anterior longitudinal ligament thickness at the sacral promontory level was 1.9 (range 1.2-2.5) mm. Median fifth lumbar to first sacral disc height was 16 (8.3-17) mm. CONCLUSION: Awareness of the first sacral nerve position, approximately 2.5 cm below the midpoint of the sacral promontory and 2 cm to the right of midline, should help anticipate and avoid somatic nerve injury during sacrocolpopexy. Knowledge of the approximate 2-mm thickness of the anterior longitudinal ligament should help reduce risk of discitis and osteomyelitis, especially when graft is affixed above the level of the sacral promontory.

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.

Distance From Cervicovaginal Junction to Anterior Peritoneal Reflection Measured During Vaginal Hysterectomy.

OBJECTIVE: To quantify the distance of the dissection plane from the cervicovaginal junction to the anterior peritoneal reflection for vaginal hysterectomy. METHODS: This is a descriptive study examining the dissection plane for anterior colpotomy in 22 surgical patients undergoing vaginal hysterectomy and in nine cadaver specimens. Intraoperatively, the distance from the vaginal incision to the anterior peritoneal reflection was measured on the uterus after removal. In nine of these patients, this distance was also measured before anterior peritoneal incision. Embalmed cadavers with intact pelvic viscera were dissected and the distance of the same dissection plane was measured. RESULTS: Median (interquartile range) surgical patient age was 51.5 (42-63) years and the main surgical indications were abnormal uterine bleeding and pelvic organ prolapse. In these patients, the median (interquartile range) distance from cervicovaginal incision to anterior peritoneal reflection was 3.4 (2.6-3.7) cm. In cadavers, the median (interquartile range) age was 81 (72-86) years with a measured distance of 2.7 (2.4-2.9) cm. CONCLUSION: When performing a vaginal hysterectomy, surgeons can expect a median (range) dissection distance of 3.4 (1.8-4.6) cm from initial incision to the peritoneal reflection for anterior colpotomy.

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.

Anatomic variations of pudendal nerve within pelvis and pudendal canal: clinical applications.

OBJECTIVE: The objective of the study was to examine the anatomic variation of the pudendal nerve in the pelvis, on the dorsal surface of the sacrospinous ligament, and in the pudendal canal. STUDY DESIGN: Detailed dissections of the pudendal nerve were performed in unembalmed female cadavers. Pelvic measurements included the distance from the origin of the pudendal nerve to the tip of ischial spine and the nerve width at its origin. The length of the pudendal canal was measured. The inferior rectal nerve was identified in the ischioanal fossa and its course documented. Lastly, the relationship of the pudendal nerve to the dorsal surface of the sacrospinous ligament was examined after transecting the lateral surface of the sacrospinous ligament. Descriptive statistics were used for data analyses and reporting. RESULTS: Thirteen female cadavers (26 hemipelvises) were examined. A single pudendal nerve trunk was identified in 61.5% of hemipelvises. The median distance from the point of the pudendal nerve formation to the ischial spine was 27.5 mm (range, 14.5-37 mm). The width of the pudendal nerve in the pelvis was 4.5 mm (range, 2.5-6.3 mm). The length of the pudendal canal was 40.5 mm (range, 20.5-54.5 mm). The inferior rectal nerve was noted to enter the pudendal canal in 42.3% of hemipelvises; in these cases, the nerve exited the canal at a distance of 32.5 mm (range, 16-45 mm) from the ischial spine. In the remaining specimens, the inferior rectal nerve passed behind the sacrospinous ligament and entered the ischioanal fossa without entering the pudendal canal. In all specimens, the pudendal nerve was fixed by connective tissue to the dorsal surface of the sacrospinous ligament. CONCLUSION: Great variability exists in pudendal nerve anatomy. Fixation of the pudendal nerve to the dorsal surface of the sacrospinous ligament is a consistent finding; thus, pudendal neuralgia attributed to nerve entrapment may be overestimated. The path of the inferior rectal nerve relative to the pudendal canal may have implications in the development of anorectal symptoms. Improved characterization of the pudendal nerve and its branches can help avoid intraoperative complications and enhance existing treatment modalities for pudendal neuropathy.

Anatomic relationships of psoas muscle: clinical applications to psoas hitch ureteral reimplantation.

OBJECTIVE: The objective of the study was to examine the anatomic relationship of the genitofemoral and femoral nerves to the psoas major muscle. STUDY DESIGN: Dissections were performed in 17 unembalmed female cadavers. Point A was used as the approximate location for placement of psoas hitch sutures and as the reference point from which all measurements were taken. Measurements included the width of the psoas major muscle, psoas minor tendon, genitofemoral nerve branches, and femoral nerve. The relative location of the genitofemoral and femoral nerves to point A and the presence or absence of a psoas minor tendon were documented. RESULTS: The psoas minor tendon was absent on at least 1 side in 11 specimens (64.7%). The median width of the psoas minor tendon was 7 mm (range, 3-11.5 mm). The median width and depth of the psoas major muscle was 21.5 mm (range, 10-35 mm) and 20.0 mm (range, 11.5-32 mm), respectively. The median width of the genitofemoral nerve was 2 mm (range, 1-4.5 mm) and that of the femoral nerve was 6.3 mm (range, 5-10.5 mm). Overall, 54 genitofemoral nerve branches were identified in 17 cadavers, 30 medial (55.5%), 22 lateral (40.7%), and 2 directly overlying point A (3.7%). CONCLUSION: The exact location for the placement of the psoas hitch sutures will vary, depending on the location of the ureteral injury and the anatomy of the psoas muscle and surrounding structures. A thorough understanding of this regional anatomy should optimize the placement of psoas hitch sutures during ureteral reimplantation procedures and help avoid nerve and vessel injury.