The female inferior hypogastric (= pelvic) plexus: anatomical and radiological description of the plexus and its afferences—applications to pelvic surgery

Key Anatomical Concepts, Landmarks, and Proposed Terminology for Nerve-Sparing Gynecologic Surgery: A Narrative Review

OBJECTIVE

To synthesize the terminology utilized in nerve-sparing surgical literature and propose standardized and nonconflicting terms to allow for consistent vocabulary.

DESIGN

We performed a literature search on PubMed using the search terms "pelvis" and "nerve-sparing." Nongynecologic surgery and animal studies were excluded. A narrative review was performed, focusing on nerves, fasciae, ligaments, and retroperitoneal spaces. Terms from included papers were discussed by all authors, who are surgeons versed in nerve-sparing procedures and one anatomist, and recommendations were made regarding the most appropriate terms based on the frequency of occurrence in the literature and the possibility of overlapping names with other structures.

RESULTS

224 articles were identified, with 81 included in the full-text review. Overall, 48% of articles focused on cervical cancer and 26% on deeply infiltrating endometriosis. Findings were synthesized both narratively and visually. Inconsistencies in pelvic anatomical nomenclature were prevalent across publications. The structure with the most varied terminology was the rectal branch of the inferior hypogastric plexus with 14 names. A standardized terminology for pelvic autonomic nerve structures, fasciae, ligaments, and retroperitoneal spaces was proposed to avoid conflicting terms.

CONCLUSION

Surgeons and anatomists should use consistent terminology to facilitate increased uptake of nerve-sparing techniques in gynecologic surgery through a better understanding of surgical technique description. We have proposed a standardized terminology believed to facilitate this goal.

Entrapped by pain: The diagnosis and management of endometriosis affecting somatic nerves

Somatic nerve entrapment caused by endometriosis is an underrecognized and often misdiagnosed issue that leads to many women suffering unnecessarily. While the classic symptoms of endometriosis are well-known to the gynaecologic surgeon, the dermatomal-type pain caused by endometriosis impacting neural structures is not within gynecologic day-to-day practice, which often complicates diagnosis and delays treatment. A thorough understanding of pelvic neuroanatomy and a neuropelveologic approach is required for accurate assessments of patients with endometriosis and nerve entrapment. Magnetic resonance imaging is the preferred imaging modality for this presentation of endometriosis. Surgical management with laparoscopic or robotic-assisted techniques is the preferred approach to treatment, with excellent long-term results reported after nerve detrapment and endometriosis excision. The review calls for increased awareness and education on the links between endometriosis and the nervous system, advocating for patient-centered care and further research to refine the diagnosis and treatment of this challenging condition.

Anatomical Location of the Vesical Branches of the Inferior Hypogastric Plexus in Human Cadavers

We have demonstrated in canines that somatic nerve transfer to vesical branches of the inferior hypogastric plexus (IHP) can be used for bladder reinnervation after spinal root injury. Yet, the complex anatomy of the IHP hinders the clinical application of this repair strategy. Here, using human cadavers, we clarify the spatial relationships of the vesical branches of the IHP and nearby pelvic ganglia, with the ureteral orifice of the bladder. Forty-four pelvic regions were examined in 30 human cadavers. Gross post-mortem and intra-operative approaches (open anterior abdominal, manual laparoscopic, and robot-assisted) were used. Nerve branch distances and diameters were measured after thorough visual inspection and gentle dissection, so as to not distort tissue. The IHP had between 1 to 4 vesical branches (2.33 ± 0.72, mean ± SD) with average diameters of 0.51 ± 0.06 mm. Vesical branches from the IHP arose from a grossly visible pelvic ganglion in 93% of cases (confirmed histologically). The pelvic ganglion was typically located 7.11 ± 6.11 mm posterolateral to the ureteral orifice in 69% of specimens. With this in-depth characterization, vesical branches from the IHP can be safely located both posterolateral to the ureteral orifice and emanating from a more proximal ganglionic enlargement during surgical procedures.

The implications of the anatomy of the nerves and vessels in the treatment of rectosigmoid endometriosis

Endometriosis is a common benign gynecological disease characterized by the presence of endometrial glands and stroma outside the uterus. It can be defined as endometrioma, superficial peritoneal endometriosis or deep infiltrating endometriosis (DIE) depending on the location and the depth of infiltration of the organs. In 5%-12% of cases, DIE affects the digestive tract, frequently involving the distal part of the sigmoid colon and rectum. Surgery is generally recommended in cases of obstructive symptoms and in cases with pain that is non-responsive to medical treatment. Selection of the most optimal surgical technique for the treatment of bowel endometriosis must consider different variables, including the number of lesions, eventual multifocal lesions, as well as length, width and grade of infiltration into the bowel wall. Except for some major and widely accepted indications regarding bowel resection, established international guidelines are not clear on when to employ a more conservative approach like rectal shaving or discoid resection, and when, instead, to opt for bowel resection. Damage to the pelvic autonomic nervous system may be avoided by detection of the middle rectal artery, where its relationship with female pelvic nerve fibers allows its use as an anatomical landmark. To reduce the risk of potential vascular and nervous complications related to bowel resection, a less invasive approach such as shaving or discoid resection can be considered as potential treatment options. Additionally, the middle rectal artery can be used as a reference point in cases of upper bowel resection, where a trans mesorectal technique should be preferred to prevent devascularization and denervation of the bowel segments not affected by the disease.

Advanced Insights into Human Uterine Innervation: Implications for Endometriosis and Pelvic Pain

(1) Background: Understanding uterine innervation, an essential aspect of female reproductive biology, has often been overlooked. Nevertheless, the complex architecture of uterine innervation plays a significant role in conditions such as endometriosis. Recently, advances in histological techniques have provided unprecedented details about uterine innervation, highlighting its intricate structure, distribution, and density. The intricate nature of uterine innervation and its influence on pathologies such as endometriosis has garnered increasing attention. (2) Objectives: This review aims to compile, analyze, and summarize the existing research on uterine innervation, and investigate its implications for the pathogenesis of endometriosis and associated pain. (3) Methods: A systematic review was conducted in line with PRISMA guidelines. Using the PubMed database, we searched relevant keywords such as "uterine innervation", "endometriosis", and "pain association". (4) Results: The initial literature search yielded a total of 3300 potential studies. Of these, 45 studies met our inclusion criteria and were included in the final review. The analyzed studies consistently demonstrated that the majority of studies focused on macroscopic dissection of uterine innervation for surgical purposes. Fewer studies focused on micro-innervation for uterine innervation. For endometriosis, few studies focused on neural pain pathways whereas many studies underlined an increase in nerve fiber density within ectopic endometrial tissue. This heightened innervation is suggested as a key contributor to the chronic pain experienced by endometriosis patients. (5) Conclusions: The understanding of uterine innervation, and its alterations in endometriosis, offer promising avenues for research and potential treatment.

Surgical Anatomy and Dissection of the Hypogastric Plexus in Nerve-Sparing Radical Hysterectomy

Radical hysterectomy is a central surgical procedure in gynecological oncology. A nerve-sparing approach is essential to minimize complications from iatrogenic injury to the pelvic nerves, resulting in postoperative urinary, anorectal, and sexual dysfunction. The hypogastric plexus (HP), a complex network of sympathetic and parasympathetic nerves, plays a critical role in pelvic autonomic innervation. This article offers a comprehensive overview of the surgical anatomy of the HP and provides a step-by-step description of HP dissection, with a particular emphasis on preserving the bladder nerve branches of the inferior HP. A thorough understanding and mastery of the anatomical and surgical nuances of HP dissection are crucial for optimizing outcomes in nerve-sparing gynecologic-oncological procedures.

Applied anatomy of female pelvic plexus for nerve-sparing radical hysterectomy(NSRH)

BACKGROUND

Nerve-sparing radical hysterectomy(NSRH)has the advantage of reducing postoperative complications and improving postoperative quality of life. The separation and protection of the pelvic plexus in NSRH is extremely important and challenging.

METHODS

24 female cadaveric hemipelves were dissected. Morphologic patterns and compositions of pelvic plexus as well as relationship of pelvic plexus to the surrounding structures were observed and documented.

RESULTS

Two patterns of superior hypogastric plexus were observed, including fenestrated and cord-like shape. The origin of bilateral hypogastric nerves were inferiorly to upper margin of promontory about 1.6 ± 0.1 cm and parallel to the ureter in front of the sacrum. Pelvic splanchnic nerves(PSN)from the second sacral nerve, the third sacral nerve and the forth sacral nerve were observed combing with the hypogastric nerves within the lateral rectal ligament. The sacral sympathetic trunk can be identified anteriorly or medially to the anterior sacral foramen. We identified the boundaries of pelvic plexus as following: the upper margin is formed by the PSNs from the third sacral nerve, posterior margin by inferior rectal artery, and anteriorly by vesical venous plexus. The uterine branches from pelvic plexus were observed accompanying with uterine artery, while other branches were inferiorly to the artery. The PSNs were located beneath the deep uterine veins within the cardinal ligament. The upper margin of pelvic plexus was observed directly approach to urinary bladder within the vesico-vaginal ligament as a single trunk accompanying with ureter, between the middle and inferior vesical veins.

CONCLUSIONS

Our study clarified the intricate arrangement, distribution and relationship of female pelvic plexus and the related structures to provide reference index for NSRH application. The innervation patterns of bladder and uterine were clarified, and by tracing these visceral branches of pelvic plexus, we suggest several new important land markers for NSRH.

The distribution of the inferior hypogastric plexus in female pelvis

Elements that comprise the inferior hypogastric plexus are difficult to expose, intricate, and highly variable and can easily be damaged during local surgical procedures. We aimed to highlight, through dissection, the origin, formation, and distribution of the hypogastric nervous structures and follow them in the female pelvis. We performed detailed dissections on 7 female formalin-fixed cadavers, focusing on structures surrounding the pelvic organs. For each hemipelvis, we removed the peritoneum from the pelvic floor, and after we identified the hypogastric nerves, we continued our dissection towards the inferior hypogastric plexuses, following the branches of the latter. Laterorectally, the hypogastric nerves form the inferior hypogastric plexus, a variable structure - nervous lamina, neuronal network (more frequently), or sometimes a combination of them. We identified three components of the inferior hypogastric plexus. The anterior bundle travels towards the base of the urinary bladder, the middle part innervates the uterus and the vagina, and the posterior segment provides the innervation of the rectum. The plexus can be identified after removing the pelvic peritoneum and the subperitoneal adipose tissue. Intraoperatively, the structures can be preserved by using an immediately-subperitoneal dissection plane. The variable branches are relatively well-organized around the pelvic vessels, supplying the urinary bladder, the genital organs, and the rectum. The ureter is surrounded by some branches, especially in its last segment, and it also receives innervation directly from the hypogastric nerve. Close to the viscera, the nerves enter neurovascular plexuses, making the intraoperative separation of the nerves and the vessels virtually impossible.

Anatomy of the vesicovaginal fascia and its relation to branches of the inferior hypogastric plexus

The inferior hypogastric plexus (IHP) lies in the extraperitoneal pelvis, and supplies branches to pelvic and perineal viscera. In men, the rectoprostatic fascia (Denonvillier's fascia) forms a distinct double fascial layer between the seminal glands and the rectum. The hypogastric nerve projections to the prostate and seminal glands run anterior to this. An analagous fascial layer in women between the vagina and cervix posteriorly and the urinary bladder anteriorly has recently been described. The purpose of this study was to examine the anatomy of the vesicovaginal fascia (VVF) and to determine its relationship to the anterior branches of the IHP. This dissection study examined the fascial layers between the posterior urinary bladder and anterior vagina/cervix (VVF) in 15 female embalmed cadavers and three fresh specimens. Anterior branches of the IHP were identified and followed distally. The relationship between these nerve projections and the VVF was examined. In 16 dissection, the VVF was identified as a complete fascial plane extending beneath the vesicouterine pouch to the neck of the bladder inferiorly and to the endopelvic fascia laterally. Anterior projections from the hypogastric nerves and IHP maintained an extraperitoneal course passing anteriorly to the VVF towards the urinary bladder The VVF is a distinct fascial structure and projections of the hypogastric nerves pass anterior to this. This may have implications for nerve sparing hysterectomy.

Inferior Hypogastric Block for the Treatment of Chronic Pelvic Pain

Context

Pelvic pain is described as pain originating from the visceral or somatic system localizing to the pelvis, the anterior abdominal wall at the level of or below the umbilicus, lumbosacral back in either men or women.

Evidence Acquisition

Narrative review.

Results

Chronic pelvic pain can be a complex disorder that may involve multiple systems such as urogynecological, gastrointestinal, neuromusculoskeletal, and psychosocial systems. The etiopathogenesis for chronic pain remains unknown for many patients. For achieving optimal patient management, a multimodal and individualized assessment of each patient is the best strategy.

Conclusions

There are non-pharmacologic treatments as well as pharmacologic treatments. In addition to these treatment options, inferior hypogastric plexus block is a promising treatment modality.

Review: Pelvic nerves - from anatomy and physiology to clinical applications

A prerequisite for nerve-sparing pelvic surgery is a thorough understanding of the topographic anatomy of the fine and intricate pelvic nerve networks, and their connections to the central nervous system. Insights into the functions of pelvic nerves will help to interpret disease symptoms correctly and improve treatment. In this article, we review the anatomy and physiology of autonomic pelvic nerves, including their topography and putative functions. The aim is to achieve a better understanding of the mechanisms of pelvic pain and functional disorders, as well as improve their diagnosis and treatment. The information will also serve as a basis for counseling patients with chronic illnesses. A profound understanding of pelvic neuroanatomy will permit complex surgery in the pelvis without relevant nerve injury.

Progress in research of sacral nerve stimulation

Sacral nerve stimulation (SNS) is well-known as a minimally invasive treatment. Originally, it was mainly used to treat urinary system diseases such as urge urinary incontinence. Gradually, it is used to treat digestive system diseases such as fecal incontinence and chronic constipation. SNS is a method in which electrical pulse signals are sent out through pulse generators to stimulate the sacral nerve directly or indirectly, thus modulating the nerve reflex of the bladder, urethra, anus, colon, and rectum and improving abnormal nerve regulation to achieve the therapeutic effect. The regulation of the sacral nerve is often carried out by inserting electrodes into the sacral spinal canal S_2-4 (mostly S₃), and the symptoms are improved by complex regulation of spinal reflex and supraspinal reflex. However, the exact mechanism is still unclear. Many studies have shown that SNS plays a key role in the treatment of many diseases of the urinary system and digestive system. This paper reviews the progress in the research of SNS.

Visualizing the autonomic and somatic innervation of the female pelvis with 3D MR neurography: a feasibility study

BACKGROUND

Treatment of female pelvic malignancies often causes pelvic nerve damage. Magnetic resonance (MR) neurography mapping the female pelvic innervation could aid in treatment planning.

PURPOSE

To depict female autonomic and somatic pelvic innervation using a modified 3D NerveVIEW sequence.

MATERIAL AND METHODS

Prospective study in 20 female volunteers (n = 6 normal, n = 14 cervical pathology) who underwent a modified 3D short TI inversion recovery (STIR) turbo spin-echo (TSE) scan with a motion-sensitive driven equilibrium (MSDE) preparation radiofrequency pulse and flow compensation. Modifications included offset independent trapezoid (OIT) pulses for inversion and MSDE refocusing. Maximum intensity projections (MIP) were evaluated by two observers (Observer 1, Observer 2); image quality was scored as 2 = high, 1 = medium, or 0 = low with the sciatic nerve serving as a reference. Conspicuity of autonomic superior (SHP) and bilateral inferior hypogastric plexuses (IHP), hypogastric nerves, and somatic pelvic nerves (sciatic, pudendal) was scored as 2 = well-defined, 1 = poorly defined, or 0 = not seen, and inter-observer agreement was determined.

RESULTS

Images were of medium to high quality according to both observers agreeing in 15/20 (75%) of individuals. SHP and bilateral hypogastric nerves were seen in 30/60 (50%) of cases by both observers. Bilateral IHP was seen in 85% (34/40) by Observer 1 and in 75% (30/40) by Observer 2. Sciatic nerves were well identified in all cases, while pudendal nerves were seen bilaterally by Observer 1 in 65% (26/40) and by Observer 2 in 72.5% (29/40). Agreement between observers for scoring nerve conspicuity was in the range of 60%-100%.

CONCLUSION

Modified 3D NerveVIEW renders high-quality images of the female autonomic and pudendal nerves.

Sex-Sparing Robot-Assisted Radical Cystectomy with Intracorporeal Padua Ileal Neobladder in Female: Surgical Technique, Perioperative, Oncologic and Functional Outcomes

Our aim was to illustrate our technique of sex-sparing (SS)-robot-assisted radical cystectomy (RARC) in female patients receiving an intracorporeal neobladder (iN). From January 2013 to June 2018, 11 female patients underwent SS-RARC-iN at a single tertiary referral center. Inclusion criteria were a cT ≤ 2 N0 M0 bladder tumor at baseline imaging (CT or MRI) and an absence of tumors in the bladder neck, trigone and urethra at TURB. Baseline, perioperative, and outcomes at one year were reported. The median operative time was 255 min and the median hospital stay was seven days. Low-grade Clavien complications occurred in four patients (36.3%), while high-grade complications were not observed in any. Seven patients (63.7%) had an organ-confined disease at the pathologic specimen; nodal involvement and positive surgical margins were not detected in any of the cases. At a median follow-up of 28 months (IQR 14–51), no patients developed new onset of chronic kidney disease stage 3b. After one year, daytime and nighttime continence rates were 90.9% and 86.4% respectively. Quality of life as well as physical and emotional functioning improved significantly over time (all p ≤ 0.04), while urinary symptoms and sexual function worsened at three months with a significant recovery taking place at one year (all p ≤ 0.04). Overall, 8 out of 11 patients (72.7%) were sexually active at the 12-month evaluation. In select female patients, SS-RARC-iN is an oncologically sound procedure associated with favorable perioperative and functional outcomes.

The effects of Bisphenol A (BPA) on sympathetic nerve fibers in the uterine wall of the domestic pig

Bisphenol A (BPA), used in the production of plastic, shows multidirectional negative effects on the living organism. BPA may affect the reproductive and nervous systems; however, its influence on the nerves supplying the uterus has not been studied. During the present study, the impact of BPA on the sympathetic nerves in the uterus was investigated using a double immunofluorescence technique. The results have shown that even low doses of BPA may change the neurochemical characterization of uterine sympathetic nerves, and the severity of these changes depends on the part of the uterus and the dose of the toxic substance. Probably the changes observed during the present study resulted from the neurotoxic and/or pro-inflammatory activity of BPA, but the exact mechanism for the observed fluctuation still remains unknown. The fluctuations of the neurochemical characterization of the uterine intramural nerves may be the first subclinical signs of harmful exposure to BPA.

Identification of a low risk population for parametrial invasion in patients with early-stage cervical cancer

Background

Recent studies have challenged radical procedures for less extensive surgery in selected patients with early-stage cervical cancer at low risk of parametrial invasion. Our objective was to identify a subgroup of patients at low risk of parametrial invasion among women having undergone surgical treatment.

Methods

Data of 1447 patients with cervical cancer treated between 1996 and 2016 were extracted from maintained databases of 10 French University hospitals. Patients with early-stage (IA2–IIA) disease treated by radical surgery including hysterectomy and trachelectomy, were selected for further analysis. The Kaplan–Meier method was used to estimate the survival distribution. A Cox proportional hazards model including all the parameters statistically significant in univariate analysis, was used to account for the influence of multiple variables.

Results

Out of the 263 patients included for analysis, on final pathology analysis 28 (10.6%) had parametrial invasion and 235 (89.4%) did not. Factors significantly associated with parametrial invasion on multivariate analysis were: age > 65 years, tumor > 30 mm in diameter measured by MRI, lymphovascular space invasion (LVSI) on pathologic analysis. Among the 235 patients with negative pelvic lymph nodes, parametrial disease was seen in only 7.6% compared with 30.8% of those with positive pelvic nodes (p < 0.001). In a subgroup of patients presenting tumors < 30 mm, negative pelvic status and no LVSI, the risk of parametrial invasion fell to 0.6% (1/173 patients).

Conclusion

Our analysis suggests that there is a subgroup of patients at very low risk of parametrial invasion, potentially eligible for less radical procedures.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1531-6) contains supplementary material, which is available to authorized users.

A step towards stereotactic navigation during pelvic surgery: 3D nerve topography

Background

Long-term morbidity after multimodal treatment for rectal cancer is suggested to be mainly made up by nerve-injury-related dysfunctions. Stereotactic navigation for rectal surgery was shown to be feasible and will be facilitated by highlighting structures at risk of iatrogenic damage. The aim of this study was to investigate the ability to make a 3D map of the pelvic nerves with magnetic resonance imaging (MRI).

Methods

A systematic review was performed to identify a main positional reference for each pelvic nerve and plexus. The nerves were manually delineated in 20 volunteers who were scanned with a 3-T MRI. The nerve identifiability rate and the likelihood of nerve identification correctness were determined.

Results

The analysis included 61 studies on pelvic nerve anatomy. A main positional reference was defined for each nerve. On MRI, the sacral nerves, the lumbosacral plexus, and the obturator nerve could be identified bilaterally in all volunteers. The sympathetic trunk could be identified in 19 of 20 volunteers bilaterally (95%). The superior hypogastric plexus, the hypogastric nerve, and the inferior hypogastric plexus could be identified bilaterally in 14 (70%), 16 (80%), and 14 (70%) of the 20 volunteers, respectively. The pudendal nerve could be identified in 17 (85%) volunteers on the right side and in 13 (65%) volunteers on the left side. The levator ani nerve could be identified in only a few volunteers. Except for the levator ani nerve, the radiologist and the anatomist agreed that the delineated nerve depicted the correct nerve in 100% of the cases.

Conclusion

Pelvic nerves at risk of injury are usually visible on high-resolution MRI with dedicated scanning protocols. A specific knowledge of their course and its application in stereotactic navigation is suggested to improve quality of life by decreasing the likelihood of nerve injury.

Electronic supplementary material

The online version of this article (10.1007/s00464-018-6086-3) contains supplementary material, which is available to authorized users.

The effect of sacral neuromodulation on pregnancy: a systematic review

INTRODUCTION AND HYPOTHESIS

To evaluate the effects of sacral neuromodulation (SNM) on pregnancy and the impact of delivery on SNM function.

METHODS

A systematic search was conducted through January 2016. We selected studies including women who had SNM and a subsequent pregnancy.

RESULTS

Out of 2,316, eight studies were included, comprising 22 patients (26 pregnancies). SNM indications were Fowler's syndrome in 11, urinary retention in 6, fecal incontinence in 1, fecal and urinary urgency in 1, overactive bladder in 1, intractable interstitial cystitis in 1, and myelodysplasia in 1. SNM stayed on in 8 pregnancies. In the remaining 18 pregnancies in which the device was deactivated, 7 had recurrent urinary tract infections, including 1 with pyelonephritis and 2 who requested reactivation owing to recurrent symptoms. Outcomes were reported in 25 pregnancies, 16 had Cesarean section (CS) and 9 had vaginal delivery, including 2 operative deliveries. Out of 25, two infants had pilonidal sinus and motor tic disorder (exhibited at the age of 2 years), both from the same mother. After delivery, SNM was functioning in 15 (60%), 4 required reprogramming, and 3 required replacement (1 had recurrence of fecal incontinence after her operative delivery with evidence of displaced leads and 1 patient reported decreased SNM effects after her two CS), and 3 decided to remove the device (2 out of 3 patients were free of symptoms after SNM deactivation and requested removal).

CONCLUSION

Within the current limited evidence, the decision regarding SNM activation or deactivation should be individualized. A registry for those patients is recommended.

Pelvic autonomic nerve preservation in radical rectal cancer surgery: changes in the past 3 decades

The advent of total mesorectal excision (TME) together with minimally invasive techniques such as laparoscopic colorectal surgery and robotic surgery has improved surgical results. However, the incidence of bladder and sexual dysfunction remains high. This may be particularly distressing for the patient and troublesome to manage for the surgeon when it does occur. The increased use of neoadjuvant and adjuvant radiotherapy is also associated with poorer functional outcomes. In this review, we evaluate current understanding of the anatomy of pelvic nerves which are divided into the areas of the inferior mesenteric artery pedicle, the lateral pelvic wall and dissection around the urogenital organs. Surgical techniques in these areas are discussed. We also discuss the results in functional outcomes of the various techniques including open, laparoscopic and robotic over the last 30 years.

Neuromodulation for the Treatment of Endometriosis-Related Symptoms

Sacral and pudendal neuromodulation have been advocated for the treatment of refractory pelvic pain, urinary urgency and retention, as well as fecal incontinence or constipation, all of which are commonly related to endometriosis and/or its surgical treatment.

In this review, the mechanisms of action and different routes of neuromodulation will be detailed, as well as all the studied applications of neuromodulation on ameliorating symptoms related to endometriosis and/or its treatment.

Concepts of the rectovaginal septum: implications for function and surgery

INTRODUCTION

In the pelvis, the rectogenital septum (RGS) separates the urogenital compartment from the digestive compartment. In men, it corresponds to Denonvilliers' rectoprostatic fascia or rectovesical septum (RVS). Its purpose-and, indeed, its existence-are controversial in women. The purpose of this review was to update knowledge about the RGS in women and, in particular, to clarify its relationship to pelvic nerves in order to deduce practical consequences of pelvic surgery and compare it to the RVS in men.

METHODS

A review of the anatomical and surgical literature was undertaken. Evidence for embryological origin, composition, and surgical importance of the RGS in women and men is suggested.

RESULTS

This manuscript presents evidence of the existence of the RGS in both women (rectovaginal septum, RVaS) and men (rectovesical septum, RVS). It originates from the genital structures and extends from the rectogenital pouch to the perineal body. It is composed of connective tissue associated with bundles of smooth muscle cells and has lateral expansions in close contact with neurovascular bundles originating from the inferior hypogastric plexus. During pelvic surgery for carcinoma, preservation of nerve fibers of erectile bodies is necessary if possible. The RGS is thus an important surgical landmark during urogenital sinus surgery, prolapse surgery, and proctectomy in women as well as during proctectomy and prostatectomy in men.

CONCLUSIONS

The RGS is present in women as well as in men, with great similarities between the two sexes. It represents an important surgical landmark during pelvic nerve-sparing surgery.

Pelvic nerve injury negatively impacts female genital blood flow and induces vaginal fibrosis-implications for human nerve-sparing radical hysterectomy

OBJECTIVE

This study sought to develop a novel animal model to study the impact of nerve-sparing radical hysterectomy (NSRH) on female genital blood flow.

DESIGN

In vivo animal study.

POPULATION

Thirty Sprague-Dawley female rats.

MATERIALS AND METHODS

Female rats underwent either unilateral pelvic nerve (PN) crush (PNC; n = 9), or crush of both the PNs and all efferent nerves in the pelvic plexus ('clock-nerve crush', CNC; n = 9). Under anaesthesia, we electrically stimulated the crushed PN at 3 and 10 days after crush while monitoring blood pressure and recording clitoral and vaginal blood flows by laser Doppler. Uninjured PNs were stimulated as an internal control. Twelve additional rats were assigned either to bilateral PNC or sham surgery, and genital tissues were processed 10 days after injury for in vitro analysis.

MAIN OUTCOME MEASURES

Genital blood flow, nNOS, eNOS, collagen I-III.

RESULTS

Stimulation of the crushed PN in both groups subjected to PNC and CNC induced significantly lower peak genital blood flow at 3 and 10 days (P < 0.05) compared to stimulation of the non-crushed control PN. The immunofluorescence and Western blot analyses revealed that all injured rats exhibited more vaginal collagen III and collagen I than rats did that ad undergone sham surgeries (P < 0.05). PCN reduced nNOS expression in both clitoral and vaginal tissue.

CONCLUSIONS

Based on our study it may be hypothesised that NSRH might cause reductions of genital blood flow and vaginal fibrosis due to neurapraxia of the pelvic nerve and reductions of nNOS nerve fibres in clitoral and distal vaginal tissue.

TWEETABLE ABSTRACT

Pelvic nerve neurapraxia during nerve-sparing radical hysterectomy could lead to sexual arousal dysfunction.

Composite nerve fibers in the hypogastric and pelvic splanchnic nerves: an immunohistochemical study using elderly cadavers

To determine the proportion of nerve fibers in the hypogastric nerve (HGN) and pelvic splanchnic nerve (PSN), small tissue strips of the HGN and PSN from 12 donated elderly cadavers were examined histologically. Immunohistochemistry for neuronal nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP), and tyrosine hydroxylase (TH) was performed. More than 70% of fibers per bundle in the HGN were positive for TH at the level of the sacral promontory. In addition, NOS- (negative) and/or VIP+ (positive) fibers were observed in small areas of each nerve bundle, although the proportion of each was usually less than 10%. In the PSN near the third sacral nerve root, the proportion of nerve fibers positive for NOS and/or VIP (or TH) was below 30%. In both the HGN and PSN, the number of VIP+ fibers was usually greater than that of NOS+ fibers, with frequent co-localization of NOS and VIP. More fibers in both nerves were positive for TH than for these other markers. In contrast to pelvic plexus branches, there were no differences in the proportions of NOS+ and VIP+ fibers between nerve bundles in each of the tissue strips. Thus, target-dependent sorting of nerve fibers was not apparent in the HGN at the level of the sacral promontory or in the PSN near the third sacral nerve root. The NOS+ and/or VIP+ fibers in the HGN were most likely ascending postganglionic fibers to the colon, while those in the PSN root may be preganglionic fibers from Onuf's nucleus.

Anatomical basis of female pelvic cavity for nerve sparing radical hysterectomy

PURPOSE

The separation and sparing of the vesical branch of the inferior hypogastric plexus (IHP), to preserve the pelvic autonomic nerve, is critical and difficult in nerve sparing radical hysterectomy. Pelvic local anatomy was performed to provide the necessary anatomical information.

METHODS

Precise pelvic anatomy was performed in 15 adult corpses, and immunohistochemical analysis was carried out on the parametrial tissues of three fresh cadavers to analyze the nerve fiber type and content of the vesical branch of the IHP.

RESULTS

The deep uterine vein is located in the upper region of the cardinal ligament (CL), with three to six multiple branches and anatomical variation, including one or two cervical branches, and two to four vesical branches. Three branches were found to be most common (63.3 %). The major distribution of the vesical branch of the IHP is dorsomedial to the middle and inferior vesical veins, with less ventral and lateral distribution. There are more sympathetic fibers than parasympathetic fibers in the vesical branch. There is a region rare of vasculature and nerve between the vaginal lateral margin and the vesical branch.

CONCLUSION

The deep uterine vein is suggested as an anatomical landmark during surgery, to process the CL and preserve the pelvic splanchnic nerves. The middle and inferior vesical veins can be used as the landmark to preserve the vesical branch of the IHP.

Topohistology of sympathetic and parasympathetic nerve fibers in branches of the pelvic plexus: an immunohistochemical study using donated elderly cadavers

Although the pelvic autonomic plexus may be considered a mixture of sympathetic and parasympathetic nerves, little information on its composite fibers is available. Using 10 donated elderly cadavers, we investigated in detail the topohistology of nerve fibers in the posterior part of the periprostatic region in males and the infero-anterior part of the paracolpium in females. Neuronal nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP) were used as parasympathetic nerve markers, and tyrosine hydroxylase (TH) was used as a marker of sympathetic nerves. In the region examined, nNOS-positive nerves (containing nNOS-positive fibers) were consistently predominant numerically. All fibers positive for these markers appeared to be thin, unmyelinated fibers. Accordingly, the pelvic plexus branches were classified into 5 types: triple-positive mixed nerves (nNOS+, VIP+, TH+, thick myelinated fibers + or -); double-positive mixed nerves (nNOS+, VIP-, TH+, thick myelinated fibers + or -); nerves in arterial walls (nNOS-, VIP+, TH+, thick myelinated fibers-); non-parasympathetic nerves (nNOS-, VIP-, TH+, thick myelinated fibers + or -); (although rare) pure sensory nerve candidates (nNOS-, VIP-, TH-, thick myelinated fibers+). Triple-positive nerves were 5-6 times more numerous in the paracolpium than in the periprostatic region. Usually, the parasympathetic nerve fibers did not occupy a specific site in a nerve, and were intermingled with sympathetic fibers. This morphology might be the result of an "incidentally" adopted nerve fiber route, rather than a target-specific pathway.

Complete primary repair of bladder exstrophy is associated with detrusor underactivity type of neurogenic bladder

OBJECTIVE

To test the hypothesis that complete primary repair of bladder exstrophy (CPRE) is associated with detrussor underactivity. For this purpose, we review (1) our experience, (2) the results of the published literature as it pertains to bladder function, and (3) the known anatomic basis on which the mechanism of the observed outcome can be understood.

METHODS

The medical records of all patients who underwent CPRE by the author between 2004 and 2010 were reviewed. Attention was focused on the clinical, imaging, and urodynamic findings.

RESULTS

Four men and 2 women underwent CPRE. Follow-up ranges from 2 to 8 years. Four underwent bilateral ureteral reimplantation combined with bladder neck repair in 3. Detrusor activity (or overactivity) was not recorded in the 5 patients who underwent urodynamic studies. Four patients achieved short periods of urinary continence. The percent predicted bladder capacity, adjusted for age, ranged from 25 to 70, with a median of 60. Of the 68 publications on CPRE since 1999, none reports the presence of detrusor activity. A description of the pelvic plexus anatomy by Walsh and Donker provides a basis for the mechanism of injury resulting in the previously mentioned results: (1) complete penile disassembly eliminates the distal fixation point of the bladder-urethral plate, (2) the subsequent dissection and mobilization result in shearing injury to the microscopic pelvic plexus branches to the bladder, external sphincter, and prostatic urethra.

CONCLUSION

CPRE results in disruption of the branches of the pelvic plexus and a neurogenic bladder (detrussor underactivity).

Lymphatic and nerve distribution throughout the parametrium

BACKGROUND

Our objective was to concomitantly assess distribution of lymphatic and nerve structures in the parametrium.

METHODS

Twenty hemipelvises from ten fresh cadavers were dissected to differentiate between, three different parts of the parametrium: the lateral parametrium, the proximal and the distal part of the posterior parametrium. Histologic and immunofluorescence analyses of nerve and lymphatic structures were performed using NSE and LYVE-1 staining, respectively. The percentage of structures was independently scored as 0 (0%), 1 (1-20%), 2 (20-50%), 3 (50-80%), 4 (>80%).

RESULTS

The lateral parametrium and the proximal part of the posterior parametrium contained both nerve (scored 2.25 and 2.50, respectively) and lymphatic (scored 2.50 and 2.00, respectively) structures. The distal part of the posterior parametrium also contained numerous nerve structures (scored 2.00) but lymphatic structures were rare (scored 0.88). No difference in nerve distribution was found according to the parts of parametrium while a significantly lower distribution of lymphatic vessels was observed in the distal part of the posterior parametrium (p=0.03).

CONCLUSION

The distal part of the posterior parametrium is of high nerve density and low lymphatic density raising the issue as to whether it should be removed during radical hysterectomy.

[Uterosacral ligament and hypogastric nerve anatomical relationship. Application to deep endometriotic nodules surgery]

Endometriosis is a concern for 10 to 15% of women of childbearing age. The uterosacral ligament is the most frequent localization of deep infiltrating endometriosis. Laparoscopic excision of endometriotic nodules may lead to functional consequences due to potential hypogastric nerve lesion. Our aim is to study the anatomical relationship between the hypogastric nerve and the uterosacral ligament in order to reduce the occurrence of such nerve lesions during pelvic surgeries. We based our study on an anatomical and surgical literature review and on the anatomical dissection of a 56-year-old fresh female subject. The hypogastric nerves cross the uterosacral ligament approximately 30mm from the torus. They go through the pararectal space, 20mm below the ureter and join the inferior hypogastric plexus at the level of the intersection between the ureter and the posterior wall of the uterine artery, at approximately 20mm from the torus. No anatomical variation has been described to date in the path of the nerve, but in its presentation which may be polymorphous. Laparoscopy and robot-assisted laparoscopic surgery facilitate the pelvic nerves visualization and are the best approach for uterosacral endometriotic nodule nerve-sparing excision. Precise knowledge by the surgeon of the anatomical relationship between the hypogastric nerve and the uterosacral ligament is essential in order to decrease the risk of complication and postoperative morbidity for patient surgically treated for deep infiltrating endometriosis involving uterosacral ligament.

Voiding difficulties after vaginal mesh cystocele repair: does the perivesical dissection matter?

INTRODUCTION AND HYPOTHESIS

Our purpose was to verify whether extensive dissection toward the sacrospinous ligament (SSL) needed for mesh fixation during anterior compartment repair increases the risk of postoperative voiding difficulties.

METHODS

A total of 124 patients after anterior compartment mesh repair without simultaneous suburethral sling placement operated on in the period 2005-2012 were enrolled in this retrospective observational study. Patients with previous anti-incontinence surgery with normal urodynamics were not excluded; 30 patients with incomplete data, severe perioperative complications, and urinary retention before and after the surgery were excluded. Urinary retention was defined as post-void residual over 150 ml more than 48 h after permanent catheter removal. The rate of urinary retention after anterior compartment repair by mesh anchored to the SSL from an anterior approach (SSLS group) was compared to that following transobturator mesh repair often combined with SSL fixation from the posterior approach (TOT group).

RESULTS

Of the 94 patients considered for statistical analysis, 62 were from the SLSS group and 32 from the TOT group. The groups were comparable in age (mean 65.5 vs 66.3), body mass index (24.8 vs 25.9), and parity (2.4 vs 2.9). Patients from the SSLS group had higher rates of prior vaginal reconstructive (27 vs 19 %) and anti-incontinence surgery (26 vs 19 %). Postoperative urinary retention was statistically significantly more frequent in the SSLS group compared to the TOT group [(17 (27 %) vs 2 (6.25 %), odds ratio 5.7, 95 % confidence interval 1.2-26.3, p = 0.027]. Hospital discharge with self-catheterization was statistically insignificantly more frequent in the SSLS group [8 % (5) vs 3 % (1)].

CONCLUSIONS

Extensive dissection needed for SSL suspension from an anterior approach may lead to more frequent postoperative voiding difficulties. This phenomenon could be explained by more considerable injury to pelvic splanchnic nerves during the dissection. A large prospective study is needed for validation of our results.

Anatomy and histology of apical support: a literature review concerning cardinal and uterosacral ligaments

The objective of this work was to collect and summarize relevant literature on the anatomy, histology, and imaging of apical support of the upper vagina and the uterus provided by the cardinal (CL) and uterosacral (USL) ligaments. A literature search in English, French, and German languages was carried out with the keywords apical support, cardinal ligament, transverse cervical ligament, Mackenrodt ligament, parametrium, paracervix, retinaculum uteri, web, uterosacral ligament, and sacrouterine ligament in the PubMed database. Other relevant journal and textbook articles were sought by retrieving references cited in previous PubMed articles. Fifty references were examined in peer-reviewed journals and textbooks. The USL extends from the S2 to the S4 vertebra region to the dorsal margin of the uterine cervix and/or to the upper third of the posterior vaginal wall. It has a superficial and deep component. Autonomous nerve fibers are a major constituent of the deep USL. CL is defined as a perivascular sheath with a proximal insertion around the origin of the internal iliac artery and a distal insertion on the cervix and/or vagina. It is divided into a cranial (vascular) and a caudal (neural) portions. Histologically, it contains mainly vessels, with no distinct band of connective tissue. Both the deep USL and the caudal CL are closely related to the inferior hypogastric plexus. USL and CL are visceral ligaments, with mesentery-like structures containing vessels, nerves, connective tissue, and adipose tissue.

Effects of vaginal hysterectomy on anorectal sensorimotor functions--a prospective study

BACKGROUND

While bowel and bladder dysfunction are recognized consequences of a radical hysterectomy, the effects of a simple hysterectomy on anorectal sensorimotor functions, particularly rectal sensation, vary among studies and the effects on rectal compliance remain unknown. Our aims were to prospectively evaluate anorectal sensorimotor functions before and after a hysterectomy.

METHODS

Anal pressures, rectal compliance, capacity, sensation, and bowel symptoms were assessed before, at 2 months, and at 1 year after a simple vaginal hysterectomy for benign indications in 19 patients. Rectal staircase (0-44 mmHg, 4-mmHg steps), ramp (0-200 mL at 50, 200 and 600 mL min(-1)) and phasic distentions (8, 16, and 24 mmHg above operating pressure) were performed.

KEY RESULTS

Anal resting (63 ± 4 before, 56 ± 4 mmHg after) and squeeze pressures (124 ± 12 before, 124 ± 12 mmHg after), rectal compliance and capacity (285 ± 12 before, 290 ± 11 mL 1 year after), and perception of phasic distentions were not different before vs after a hysterectomy. Sensory thresholds for first sensation and the desire to defecate were also not different, but pressure and volume thresholds for urgency were somewhat greater (Hazard ratio = 0.7, 95% CI [0.5, 1.0]) 1 year after (vs before) a hysterectomy. Rectal pressures were higher (P < 0.0001) during fast compared with slow ramp distention; this rate effect was greater at 1 year after a hysterectomy, particularly at 100 mL (P = 0.04).

CONCLUSIONS & INFERENCES

A simple vaginal hysterectomy has relatively modest effects (i.e., somewhat reduced rectal urgency and increased stiffness during rapid distention) on rectal sensorimotor functions.

Continuous intraoperative monitoring of autonomic nerves during low anterior rectal resection: an innovative approach for observation of functional nerve integrity in pelvic surgery

PURPOSE

The aim of this study was to develop a methodological setup for continuous intraoperative neuromonitoring with intent to improve nerve-sparing pelvic surgery.

METHODS

Fourteen pigs underwent low anterior rectal resection. Continuous stimulation of pelvic autonomic nerves was carried out with a newly developed tripolar surface electrode during lateral, anterolateral, and anterior mesorectal dissection. Neuromonitoring was performed under electromyography of the autonomic innervated internal anal sphincter.

RESULTS

Continuous neuromonitoring resulted in significantly increased electromyographic amplitudes of the internal anal sphincter, confirming intact innervation throughout the whole dissection in each animal (median 0.9 μV, interquartile range 0.5; 1.5 vs. median 3.4 μV, interquartile range 2.1; 4.7) (p < 0.001). The median dissection time in each animal was 10 min within a median number of ten (range 8-13) tripolar electric stimulations.

CONCLUSION

The present study is the first to demonstrate that continuous intraoperative monitoring of pelvic autonomic nerves during low anterior rectal resection is feasible.

Where does pelvic nerve injury occur during rectal surgery for cancer?

AIM

Optimal treatment of rectal adenocarcinoma involves total mesorectal excision with nerve-preserving dissection. Urinary and sexual dysfunction is still frequent following these procedures. Improved knowledge of pelvic nerve anatomy may help reduce this and define the key anatomical zones at risk.

METHOD

The MEDLINE database was searched for available literature on pelvic nerve anatomy and damage after rectal surgery using the key words 'autonomic nerve', 'pelvic nerve', 'colorectal surgery', and 'genitourinary dysfunction'. All relevant French and English publications up to May 2010 were reviewed. Reviewed data were illustrated using 3D reconstruction of the foetal pelvis.

RESULTS

The ligation of the inferior mesenteric artery and dissection of the retrorectal space can cause damage to the superior hypogastric plexus and/or hypogastric nerve. Anterolateral dissection in the 'lateral ligament' area and division of Denonvilliers' fascia can damage the inferior hypogastric plexus and efferent pathways. Perineal dissection can indirectly damage the pudendal nerve.

CONCLUSIONS

In most cases, the pelvic nerves can be preserved during rectal surgery. Complete oncological resection may require dissection close to the nerves where the tumour is located anterolaterally where it is fixed and when the pelvis is narrow.

Hysterectomy improves sexual response? Addressing a crucial omission in the literature

The prevailing view in the literature is that hysterectomy improves the quality of life. This is based on claims that hysterectomy alleviates pain (dyspareunia and abnormal bleeding) and improves sexual response. Because hysterectomy requires cutting the sensory nerves that supply the cervix and uterus, it is surprising that the reports of deleterious effects on sexual response are so limited. However, almost all articles that we encountered report that some of the women in the studies claim that hysterectomy is detrimental to their sexual response. It is likely that the degree to which a woman's sexual response and pleasure are affected by hysterectomy depends not only on which nerves were severed by the surgery, but also the genital regions whose stimulation the woman enjoys for eliciting sexual response. Because clitoral sensation (via pudendal and genitofemoral nerves) should not be affected by hysterectomy, this surgery would not diminish sexual response in women who prefer clitoral stimulation. However, women whose preferred source of stimulation is vaginal or cervical would be more likely to experience a decrement in sensation and consequently sexual response after hysterectomy because the nerves that innervate those organs, that is, the pelvic, hypogastric, and vagus nerves, are more likely to be damaged or severed in the course of hysterectomy. However, all published reports of the effects of hysterectomy on sexual response that we encountered fail to specify the women's preferred sources of genital stimulation. As discussed in the present review, we believe that the critical lack of information as to women's preferred sources of genital stimulation is key to accounting for the discrepancies in the literature as to whether hysterectomy improves or attenuates sexual pleasure.

Autonomic-somatic communications in the human pelvis: computer-assisted anatomic dissection in male and female fetuses

Sphincter continence and sexual function require co-ordinated activity of autonomic and somatic neural pathways, which communicate at several levels in the human pelvis. However, classical dissection approaches are only of limited value for the determination and examination of thin nerve fibres belonging to autonomic supralevator and somatic infralevator pathways. In this study, we aimed to identify the location and nature of communications between these two pathways by combining specific neuronal immunohistochemical staining and three-dimensional reconstruction imaging. We studied 14 normal human fetal pelvic specimens (seven male and seven female, 15-31 weeks' gestation) by three-dimensional computer-assisted anatomic dissection (CAAD) with neural, nitrergic and myelin sheath markers. We determined the precise location and distribution of both the supra- and infralevator neural pathways, for which we provide a three-dimensional presentation. We found that the two pathways crossed each other distally in an X-shaped area in two spatial planes. They yielded dual innervation to five targets: the anal sphincter, levator ani muscles, urethral sphincter, corpus spongiosum and perineal muscles, and corpora cavernosa. The two pathways communicated at three levels: proximal supralevator, intermediary intralevator and distal infralevator. The dorsal penis/clitoris nerve (DN) had segmental nitrergic activity. The proximal DN was nNOS-negative, whereas the distal DN was nNOS-positive. Distal communication was found to involve interaction of the autonomic nitrergic cavernous nerves with somatic nitrergic branches of the DN, with nitrergic activity carried in the distal part of the nerve. In conclusion, the pelvic structures responsible for sphincter continence and sexual function receive dual innervation from the autonomic supralevator and the somatic infralevator pathways. These two pathways displayed proximal, intermediate and distal communication. The distal communication between the CN and branches of the DN extended nitrergic activity to the distal part of the cavernous bodies in fetuses of both sexes. These structures are important for erectile function, and care should therefore be taken to conserve this communication during reconstructive surgery.

Selective pelvic autonomic nerve stimulation with simultaneous intraoperative monitoring of internal anal sphincter and bladder innervation

BACKGROUND

Pelvic autonomic nerve preservation avoids postoperative functional disturbances. The aim of this feasibility study was to develop a neuromonitoring system with simultaneous intraoperative verification of internal anal sphincter (IAS) activity and intravesical pressure.

METHODS

14 pigs underwent low anterior rectal resection. During intermittent bipolar electric stimulation of the inferior hypogastric plexus (IHP) and the pelvic splanchnic nerves (PSN), electromyographic signals of the IAS and manometry of the urinary bladder were observed simultaneously.

RESULTS

Stimulation of IHP and PSN as well as simultaneous intraoperative monitoring could be realized with an adapted neuromonitoring device. Neurostimulation resulted in either bladder or IAS activation or concerted activation of both. Intravesical pressure increase as well as amplitude increase of the IAS neuromonitoring signal did not differ significantly between stimulation of IHP and PSN [6.0 cm H(2)O (interquartile range [IQR] 3.5-9.0) vs. 6.0 cm H(2)O (IQR 3.0-10.0) and 12.1 μV (IQR 3.0-36.7) vs. 40.1 μV (IQR 9.0-64.3)] (p > 0.05).

CONCLUSIONS

Pelvic autonomic nerve stimulation with simultaneous intraoperative monitoring of IAS and bladder innervation is feasible. The method may enable neuromonitoring with increasing selectivity for pelvic autonomic nerve preservation.

Neural supply to the clitoris: immunohistochemical study with three-dimensional reconstruction of cavernous nerve, spongious nerve, and dorsal clitoris nerve in human fetus

INTRODUCTION

Little detailed information is available concerning autonomic and somatic nerve supply to the clitoris, potentially causing difficulties for nerve preservation during pelvic and perineal surgery.

AIM

To identify the location and type (nitrergic, adrenergic, cholinergic and sensory) of nerve fibers in the clitoris and to provide a three-dimensional (3D) representation of their structural relationship in the human female fetus.

METHODS

Serial transverse sections were obtained from five human female fetuses (18-31 weeks of gestation) and subjected to histological and immunohistochemical investigations; digitized serial sections were used to construct a 3D representation of the pelvis.

MAIN OUTCOME MEASURES

Pelvic-perineal nerve location and type were evaluated qualitatively.

RESULTS

The female neurovascular bundle (NVB) is the anteroinferior terminal portion of the inferior hypogastric plexus that runs along the postero-lateral then lateral face of the vagina and is rich in nNOS-positive fibers. The cavernous nerve (CN) is a thin ventrocaudal collateral projection of the NVB, and this projection does not strictly follow the NVB course. The CN runs along the lateral surface of the vagina and urethra and penetrates the homolateral clitoral crus. The CN provides adrenergic, cholinergic, and nitrergic innervation to the clitoris, but not sensory innervation. The spongious nerve (SN) is the terminal and main projection of the NVB and provides nitrergic innervation to the vestibular bulbs. The dorsal clitoris nerve (DCN), somatic branche of the pudendal nerve, runs along the superior surface of the clitoral crus and body and has a segmental proerectile nitrergic activity related to communicating branches with the CN.

CONCLUSIONS

"Computer-assisted anatomic dissection" allowed the identification of the precise location and distribution of the autonomic and somatic neural supply to female erectile bodies, providing an anatomical basis for nerve-sparing surgical techniques, and participating to the understanding of neurogenic female sexual dysfunction.

Female pelvic autonomic neuroanatomy based on conventional macroscopic and computer-assisted anatomic dissections

PURPOSE

To confront nerve dissection, tissue staining, nerve immunolabelling and Computer-Assisted Anatomic Dissection (CAAD) in identifying the precise location and origin of intrapelvic autonomic nerve fibers and to provide a three-dimensional (3D) representation of their relationship to other anatomical structures.

METHODS

Serial transverse sections of the pelvic portion of five human female fetuses (18-31 weeks of gestation) were studied histologically (with hematoxylin/eosin and Masson trichrome) and immunohistochemically (anti-protein S100 antibody) digitized and reconstructed three-dimensionally with Surf driver software for Windows (Winsurf 4.3). Three fresh female adult cadavers were macroscopically dissected to individualize the inferior hypogastric plexus afferences and efferences and their anatomical relationships.

RESULTS

This combined investigation including the CAAD technique allowed identifying the precise location and distribution of the pelvic nerve elements and their relationships to female pelvic organs. Hypogastric nerves (HN) were located in the retrorectal multilaminar structure and joined the homolateral inferior hypogastric plexus (IHP) at the lateral border of the recto-uterine pouch. The intersection of the ureter with the posterior wall of the uterine artery precisely located the junction of HN and IHP. Antero-inferior branches supplying female sexual and continence organs originated from the antero-inferior angle of IHP and were bundled at the posterolateral vaginal wall.

CONCLUSIONS

CAAD is an encouraging anatomical method for the development of anatomical and surgical research and teaching. Complementary to traditional anatomical studies, it may provide useful anatomical data for the comprehension of postoperative sexual and urinary dysfunction and the development of nerve-sparing surgical techniques.

Intraoperative pelvic nerve stimulation performed under continuous electromyography of the internal anal sphincter

PURPOSE

The aim of this animal study was to investigate the effect of intraoperative pelvic nerve stimulation on internal anal sphincter electromyographic signals in order to evaluate its possible use for neuromonitoring during nerve-sparing pelvic surgery.

METHODS

Eight pigs underwent low anterior rectal resection. The intersphincteric space was exposed, and the internal (IAS) and external anal sphincter (EAS) were identified. Electromyography of both sphincters was performed with bipolar needle electrodes. Intermittent bipolar electric stimulation of the inferior hypogastric plexus and the pelvic splanchnic nerves was carried out bilaterally. The recorded signals were analyzed in its frequency spectrum.

RESULTS

In all animals, electromyographic recordings of IAS and EAS were successful. Intraoperative nerve stimulation resulted in a sudden amplitude increase in the time-based electromyographic signals of IAS (1.0 (0.5-9.0) μV vs. 4.0 (1.0-113.0) μV) and EAS (p < 0.001). The frequency spectrum of IAS in the resting state ranged from 0.15 to 5 Hz with highest activity in median at 0.77 Hz (46 cycles/min). Pelvic nerve stimulation resulted in an extended spectrum ranging from 0.15 to 20 Hz. EAS signals showed higher frequencies mainly in a range of 50 to 350 Hz. However, after muscle relaxation with pancuronium bromide, only the low frequency spectrum of the IAS signals was still present.

CONCLUSIONS

Intraoperative verification of IAS function by stimulation of pelvic autonomic nerves is possible. The IAS electromyographic response could be used to monitor pelvic autonomic nerve preservation.

The effect of sacral nerve stimulation on uterine activity: a pilot study

INTRODUCTION

Sacral nerve stimulation (SNS) is a treatment for consecutive therapy resistant faecal incontinence or constipation. Little is known about the effects of SNS on uterocervical function. Therefore, it is advised to turn off the stimulator during pregnancy or to wait with permanent implantation of the stimulator until family completion. Diagnostic ultrasound provides an, non-invasive, opportunity to study various aspects of uterine activity. The purpose of this pilot study was to assess the influence of SNS on endometrial waves of the nonpregnant uterus by ultrasound recordings.

METHOD

Six patients with an implanted SNS were included. Ultrasound recordings were performed with the stimulator turned off and in three stimulation frequencies. Uterine activity is described as wave frequency and wave direction.

RESULTS

All three premenopausal patients showed endometrial activity with the stimulator turned off. This activity was maintained with the stimulator turned on in two patients, but disappeared in one patient. All three postmenopausal patients had no endometrial activity with the stimulator turned off. In one patient there was activity with the stimulator turned on at a frequency of 21 Hz.

CONCLUSION

We have shown some effect of SNS on uterine activity. In premenopausal women we discovered that SNS seems to exhibit no effect or an inhibitory effect rather than an excitatory effect on uterine activity. Based on the preliminary results of this study, we can not recommend any guidelines for SNS usage during conception and pregnancy. A larger study in premenopausal women with SNS is needed to investigate the significance of these changes.

Nerve-sparing and individually tailored surgery for cervical cancer

Cancer of the cervix is the second most common cancer in women worldwide, with about 500,000 new cases and 273,000 deaths reported annually. Ideal surgical management of cervical cancer should reduce early and late morbidity without compromising oncological disease control. Type of surgical radicality in early cervical cancer should be a consequence of exact preoperative and intraoperative assessments of risk factors. During the past 15 years, substantial progress has been made in understanding the neuroanatomy of the autonomic pelvic plexus. This progress has resulted in individually tailored surgery for cervical cancer. The concept of preservation of autonomic nerves during radical hysterectomy has become standard in many oncogynaecological centres. Nerve-sparing radical hysterectomy and individually tailored surgery, in comparison with standard radical hysterectomy, have led to a much improved quality of life. Since 2008, there has been a new classification of radical hysterectomy, which includes nerve-sparing techniques. 5-year survival in early stage cervical cancer is 88-97% and more than 50% of women are younger than 50 years of age. Thus, we must take into consideration the quality of life of these patients. In this Review, we focus on the neuroanatomy of the pelvis and the possible damage of autonomic nerves, and suggest options for the sparing of these nerves during surgery for cervical cancer.