Surgical anatomy of the pudendal nerve and its clinical implications

Methodologies to elicit and record pudendal somatosensory evoked potentials in adult humans: A systematic review

OBJECTIVE

The purpose of this systematic review was to characterize methodologies reported in the literature to elicit and record pudendal somatosensory evoked potentials (SEPs) in human adults.

METHODS

We conducted an electronic literature search in MEDLINE, Embase, CENTRAL, and CINAHL for studies that elicited pudendal SEPs via electrical stimulation and recorded responses though electroencephalography. From included studies, we extracted methodological details of how the SEPs were evoked and recorded.

RESULTS

132 studies were included in our review. The majority of participants were male (n = 6742/8526, 79%). Almost all studies stimulated the dorsal nerve of penis/clitoris. Stimulus parameters varied, with most standardizing stimulus intensity to 2-4x perceptual threshold, pulse duration to 0.1-0.2 ms, and frequency to 3 Hz. The number of stimuli recorded varied by clinical population.

CONCLUSIONS

Our results demonstrate the inconsistencies of pudendal SEP methodology in the literature, with the majority (77%) of publications not reporting enough detail to reasonably replicate their protocol. Most research to date has been conducted in males, highlighting the paucity of female pelvic neurophysiology research.

SIGNIFICANCE

We propose a Pudendal SEP Reporting Checklist for adequate reporting of pudendal SEP protocols. Optimal sex- and patient-specific methodologies to investigate all branches of the pudendal nerve need to be established.

Pudendal nerve neurolysis outcomes for urogenital and rectal disorders in patients suffering from pudendal nerve entrapment: A systematic review

PURPOSE

Pudendal neuropathy is an uncommon condition that exhibits several symptoms depending on the site of nerve entrapment. This study aims to evaluate the efficacy of pudendal nerve neurolysis (PNN) in improving lower urinary tract symptoms, anal and/or urinary incontinence, and sexual dysfunctions.

MATERIALS AND METHODS

A systematic literature search was performed on 20 May 2023 using Scopus, PubMed, and Embase. Only English and adult papers were included. Meeting abstracts and preclinical studies were excluded.

RESULTS

Twenty-one papers were accepted, revealing significant findings in the field. The study identified four primary sites of pudendal nerve entrapment (PNE), with the most prevalent location likely being at the level of the Alcock canal. Voiding symptoms are commonly exhibited in patients with PNE. PNN improved both urgency and voiding symptoms, and urinary and anal incontinence but is less effective in cases of long-standing entrapment. Regarding sexual function, the recovery of the somatic afferent pathway results in an improvement in erectile function early after neurolysis. Complete relief of persistent genital arousal disorder occurs in women, although bilateral PNN is necessary to achieve the efficacy. PNN is associated with low-grade complications.

CONCLUSIONS

PNN emerges as a viable option for addressing urinary symptoms, fecal incontinence, erectile dysfunction, and female sexual arousal in patients suffering from PNE with minimal postoperative morbidity.

Anatomy of the pudendal nerve in clinically important areas: a pictorial essay and narrative review

PURPOSE

The pudendal nerve is an anatomical structure arising from the ventral branches of the spinal roots S2-S4. Its complex course may be affected by surrounding structures. This may result in irritation or entrapment of the nerve with subsequent clinical symptoms. Aim of this study is to review the anatomy of the pudendal nerve and to provide detailed photographic documentation of the areas with most frequent clinical impact which are essential for surgical approach.

METHODS

Major medical databases were searched to identify all anatomical studies investigating pudendal nerve and its variability, and possible clinical outcome of these variants. Extracted data consisted of morphometric parameters, arrangement of the pudendal nerve at the level of roots, formation of pudendal nerve, position according to sacrospinal and sacrotuberal ligaments and its terminal branches. One female cadaver hemipelvis was dissected with common variability of separate course of inferior rectal nerve. During dissection photodocumentation was made to record course of pudendal nerve with focus on areas with recorded pathologies and areas exposed to iatrogenic damage during surgical procedures.

RESULTS

Narrative review was done to provide background for photodocumentation. Unique photos of course of the pudendal nerve was made in areas with great clinical significance.

CONCLUSION

Knowledge of anatomical variations and course of the pudendal nerve is important for examinations and surgical interventions. Surgically exposed areas may become a site for iatrogenic damage of pudendal nerve; therefore, unique picture was made to clarify topographic relations.

Novel implantation technique for pudendal nerve peripheral nerve stimulation for treatment of chronic pelvic pain

BACKGROUND

Chronic pelvic pain (CPP) is a pervasive, difficult to treat condition affecting up to 26% of the global female and 8.2% of the global male population. Considered a form of chronic regional pain syndrome (CRPS), it is medically complex and often refractory to multimodal management. Neuromodulation has become increasingly popular in treatment of chronic neuropathic pain conditions, including CPP and CRPS. Dorsal column spinal cord stimulation and dorsal root ganglion stimulation have had some success for managing CPP meanwhile peripheral nerve stimulators (PNS) have been suggested as another viable option. However, few studies in the literature have reported successful use of PNS in treatment of CPP. Here, we detail a possible technique for pudendal PNS lead placement for management of CPP.

METHOD

This article describes a novel cephalad to caudad fluoroscopic guided technique for pudendal nerve PNS lead placement and implantation.

RESULTS

A cephalad to caudal-medial fluoroscopic guided approach as described within to successfully implant a percutaneous pudendal nerve PNS for management of CPP.

CONCLUSIONS

The pudendal nerve PNS lead placement technique noted within can be used to avoid many of the important neurovascular structures near the pelvic outlet. Further studies are needed to validate the safety and efficacy of this therapy modality but it may be a viable management option for patients with medically refractory CPP.

Origin, course, and distribution of the posterior femoral cutaneous nerve and the spatial relationship among its branches

This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral compositions of the sacral plexus, including the pudendal nerve. The buttocks and thighs of five cadavers were analyzed bilaterally. The branches emerged from the sacral plexus, which was divided dorsally to ventrally into the superior gluteal, inferior gluteal, common peroneal, tibial, and pudendal nerves. It descended lateral to the ischial tuberosity and comprised the thigh, gluteal, and perineal branches. As for the thigh and gluteal branches, the dorsoventral order of those originating from the sacral plexus corresponded to the lateromedial order of their distribution. However, the dorsoventral boundary was displaced at the inferior margin of the gluteus maximus between the thigh and gluteal branches. The perineal branch originated from the ventral branch of the nerve roots. In addition, the pudendal nerve branches, which ran medially to the ischial tuberosity, were distributed in the medial part of the inferior gluteal region. These branches should be distinguished from the gluteal branches; the former should be classified as the medial inferior cluneal nerves and the latter as the lateral ones. Finally, the medial part of the inferior gluteal region was distributed by branches of the dorsal sacral rami, which may correspond to the medial cluneal nerves. Thus, the composition of the posterior femoral cutaneous nerve is considered necessary when considering the dorsoventral relationships of the sacral plexus and boundaries of the dorsal and ventral rami.

The efficacy of peripheral nerve block on postoperative catheter-related bladder discomfort in males: A systematic review and meta-analysis

Objective

To determine the efficacy of peripheral nerve block (PNB) in preventing postoperative catheter-related bladder discomfort (CRBD).

Methods

Up to July 1, 2022, the PubMed, Embase and Cochrane Central Register of Controlled Trials databases were searched, and all articles that met the PICOS (Patient, Intervention, Comparator, Outcome, Study design) criteria were enrolled. The included trials were evaluated using the Cochrane Collaboration's tool. Patients in the block group received bilateral PNB, while those in the non-block group did not need any additional procedure or simply achieved "sham block". CRBD was quantified using the visual analog scale (VAS) score, which was questioned and recorded at 0-1 h, 1-2 h, 4-8 h, 8-12 h and 12-24 h intervals. The incidences of CRBD, moderate to severe CRBD and postoperative nausea and vomiting (PONV) were meta-analysed.

Results

Six trials with a total of 544 patients were considered. First, the block group had a lower incidence of CRBD than the non-block group at 0-1 h (OR 0.22; 95% CI, 0.18-0.08; P < 0.0001), 1-2 h (OR 0.14; 95% CI, 0.08-0.26; P < 0.00001), 4-8 h (OR 0.27; 95% CI, 0.13 to 0.58; P < 0.0008) and 8-12 h (OR 0.51; 95% CI, 0.30 to 0.87; P = 0.01). Second, the block group showed a lower incidence of moderate to severe CRBD than the non-block group at 0-1 h, 1-2 h and 4-8 h, and the ORs were 0.12 (95% CI, 0.03 to 0.49; P = 0.003), 0.17 (95% CI, 0.08 to 0.37; P < 0.00001) and 0.29 (95% CI, 0.15 to 0.55; P = 0.0002),respectively. Finally, the block group was significantly associated with a decreased incidence of PONV (OR, 0.14; 95% CI, 0.05 to 0.39; P = 0.0002).

Conclusion

This meta-analysis suggested that PNB markedly reduced the incidence and severity of early postoperative CRBD and decreased the occurrence of PONV.

Morphological Peculiarities of the Pelvic Autonomic Nervous System and Their Impact on Clinical Interventions in the Lesser Pelvic Region

Background: The aim of the work is to define the morphological peculiarities of the pelvic autonomic nervous system (ANS) and their importance in the clinical and surgical interventions in the lesser pelvis. Material and methods: Anatomical variations in the formation of the pelvic ANS were observed in 20 cadavers. The study included 17 men (85%), aged 18 to 84, and 3 women, aged 27 to 86. The average age was 53.8 years. The subjects most often died by violent death in car accidents, by asphyxia, or by sudden death. The study was approved by the Ethics Committee of the Health Care Surveillance Authority, Bratislava, Slovakia. We studied cadavers without congenital or detected anomalies, cancer, deformities of the body, or spinal or abdominal surgeries within 24 h of death. We observed a relationship between the dimensions and the number of ganglia, as well as the number and course of nerve branches and anastomoses. In the pelvic area, we observed the hypogastric plexus superior, hypogastric plexus inferior, and the truncus sympathicus. In all cadavers, we clarified the lumbosacral plexuses after evisceration. In the lumbosacral region, the roots were defined based on their participation in the formation of the plexuses. To show the intimate relationship between both systems, we also focused on the details of the structure (rami communicantes) related to the connections of the ANS with the spinal nervous system. Results: Anatomical variations in the formation of the pelvic ANS were observed in all cases. We included cases with more than two truncus sympathicus ganglia as the segmental type. The segmental form occurred in 14 (70%) cases, and was concentrated in 6 (30%) cases. Rami communicantes provided anastomoses to the spinal nerves. Small ganglia were observed on the rami communicantes. With the concentrated type, we observed the division of the sympathetic and parasympathetic systems. With the segmental and concentrated forms, symptoms of the "diffuse form" may occur, which we observed in all cases. We observed significant right-left asymmetry and differences in the formation of ganglia and anastomoses. Conclusions: This study allowed us to identify and describe the morphological peculiarities of the pelvic ANS and their possible influence on the clinical picture. Asymmetry and dependence of their occurrence on the type of ANS was observed. The variations were frequent. Their preoperative diagnosis is difficult to impossible. The absence or lack of intraoperative vigilance can lead to the damage of pelvic ANS during operations and blockades of the pelvic plexus. The acquired knowledge can be helpful in clarifying clinical signs and symptoms of these conditions.

A systematic review of treatment options for post-prostatectomy incontinence

PURPOSE

Urinary incontinence remains common in men after prostatectomy. Current guidance suggests early corrective surgery to those that are still incontinent after trying Pelvic Floor Muscle Therapy, however, other treatments are now available. This review aims to evaluate all currently available treatment options for men with post-prostatectomy incontinence (PPI).

METHODS

A search of MEDLINE and CENTRAL databases on 2/2/2021 produced 879 articles. Any study evaluating incontinence before and after a treatment protocol was eligible for inclusion. After screening, 17 randomized control trials were included, and pre-defined data points were collected. Due to heterogeneity, pooled analysis was not possible, and a descriptive synthesis was produced in accordance with PRISMA guidelines. Cochrane Risk of Bias (RoB) tool was used to evaluate all studies. The search protocol and methods for this study was registered on the PROSPERO database before the search began, ID:(CRD42021229749).

RESULTS

3/17(18%) of studies focussed on pharmacotherapy, 2/17(12%) on vibration therapies, 8/17(47%) on pelvic floor muscle therapy (PFMT), 3/17(18%) on electrical stimulation (ES), and 1/17 (6%) on extracorporeal magnetic innervation (ExMI) as their main intervention. The use of Duloxetine, Solifenacin, PFMT, ES, and ExMI all show effective reduction in incontinence in men suffering from PPI. No study in this review evaluated surgical managements for PPI.

CONCLUSION

A large number of treatments are available for PPI using an array of different methods. For this reason, a variety of treatments could be considered before early invasive procedures, to prevent unnecessary surgery and its associated negative complications.

Anatomical Study of the Variants of the Extrapelvic Part of the Pudendal Nerve

Background A comprehensive understanding of the anatomy of the extra pelvic course of the pudendal nerve and its variations is crucial when undertaking perineal and perirectal procedures to safeguard the integrity of the extrapelvic segment of the pudendal nerve and its branches. So we aimed to identify the changes in the pudendal nerve's extrapelvic branching pattern before it enters the pudendal canal and its relationships and connections. Materials and Methods A cross-sectional descriptive study was carried out on 26 formalin embalmed adult human cadavers between 20 to 65 years (16 male and 10 female) of north Indian origin. Anatomical course, variations, and connections of the pudendal nerve before entering the pudendal canal were noted. Results The extrapelvic course of the pudendal nerve was examined in 52 hemipelves (26 cadavers) after meticulous dissection. Single pudendal nerve trunk (type I) was identified in 51.9% of hemipelves. Two trunked pudendal nerve with inferior gluteal nerve piercing the sacrospinous ligament (type IIa) was observed in 13.5% of hemipelves. 23.1% of hemipelves exhibited two trunked pudendal nerves with inferior gluteal nerve not piercing the sacrospinous ligament(type IIb). Three trunked pudendal nerve (type III) was observed in 11.5% of hemipelves. In 14/52 hemipelves (26.9%), communication with the sciatic nerve was noted, whereas, in 38/52 hemipelves (73.1%), no communication with the sciatic nerve was present. Conclusion The extrapelvic course of the pudendal nerve may present with an earlier subdivision or even an aberrant connection with the sciatic nerve. These anatomical variations of the extra pelvic course of the pudendal nerve, its variations, and connections are essential for all surgeons and anesthetists operating in the perineal and perirectal region to avoid unwanted complications.

The Lost Penis Syndrome: A New Clinical Entity in Sexual Medicine

INTRODUCTION

The "lost penis syndrome" (LPS) is a term often used in non-clinical settings to describe the subjective perception of the loss of cutaneous and proprioceptive feelings of the male organ during vaginal penetration. Although deserving clinical attention, this syndrome did not receive any consideration in the medical literature. Notwithstanding, it represents a relatively unexceptional condition among patients in sexual medicine clinics, and it is often reported together with other sexual dysfunctions, especially delayed ejaculation, anejaculation, male anorgasmia and inability to maintain a full erection.

OBJECTIVES

To draft a new conceptual characterization of the LPS, defined as a lack of penile somesthetic sensations during sexual penetration due to various causes and leading to several sexual consequences in both partners.

METHODS

Based on an extensive literature review and physiological assumptions, the mechanisms contributing to friction during penovaginal intercourse, and their correlation to LPS, have been explored, as well as other nonanatomical factors possibly contributing to the loss of penile sensations.

RESULTS

Efficient penile erection and sensitivity, optimal vaginal lubrication and trophism contribute to penovaginal friction. Whenever one of these processes does not occur, loss of penile sensation defined as LPS can occur. Sociocultural, psychopathological and age-related (ie, couplepause) factors are also implicated in the etiology. Four types of LPS emerged from the literature review: anatomical and/or functional, behavioral, psychopathological and iatrogenic. According to the subtype, a wide variety of treatments can be employed, including PDE5i, testosterone replacement therapy and vaginal cosmetic surgery, as well as targeted therapy for concomitant sexual comorbidity.

CONCLUSION

We held up the mirror on LPS as a clinically existing multifactorial entity and provided medical features and hypotheses contributing to or causing the occurrence of LPS. In the light of a sociocultural and scientific perspective, we proposed a description and categorization of this syndrome hypothesizing its usefulness in daily clinical practice. Colonnello E, Limoncin E, Ciocca G, et al. The Lost Penis Syndrome: A New Clinical Entity in Sexual Medicine. Sex Med Rev 2021;XX:XXX-XXX.

A randomised-controlled, prospective study on the effect of dorsal penile nerve block after TURP on catheter-related bladder discomfort and pain

PURPOSE

In the present study, the impact of penile nerve block (PNB) on postoperative pain and Catheter-Related Bladder Discomfort (CRBD) in the transurethral resection of prostate(TURP) patients were evaluated.

METHODS

Participants of the present study were selected from patients who performed TURP under spinal anaesthesia for benign prostatic hyperplasia (BPH) between January 2018 and July 2020. The present study was planned as a single-centre, randomised-controlled prospective study in which the patients were divided into two groups. Group 1 was administered Control (n:40), and Group 2 ultrasonography(USG) guided PNB (n:40). The patients were included in the Groups, respectively. Visual analogue scale (VAS) scores were questioned and recorded in order to evaluate the postoperative pain complaints of the patients after the operation. In addition, in order to evaluate the CRBD, VAS scores were questioned and recorded as 0th, 0-1th hour, 1st-2nd hour, 2nd-4th hour, 4th-8th hour, 8th-12th hour, and 12th-24th hour. In addition, postoperative pain and need for analgesic drug were recorded. Tramadol was given to patients with moderate to severe CRBD. The findings were compared between the Groups.

RESULTS

There was no statistical difference demographic and per-operative data between Group 1 and Group 2. The CRBD and pain-related VAS scores were significantly higher in Group 1 between the 0 and 8th hours. There was no difference between VAS scores in the postoperative 8-24th hours. In total 24 hours, Group 2's need for tramadol was significantly less than Group 1. On examining the factors affecting CRBD in the multivariate analysis, age, body mass index(BMI), prostate volume, operation time do not affect CRBD statistically, and only PNB reduces CRBD (P: .029). While less drug-related complications were observed in Group 2, no serious complications related to PNB were observed.

CONCLUSION

Penile nerve block is an effective method for the decrease pain and CRBD after urological surgery. It will also reduce the need for analgesics, and provide painless patients in the postoperative period.

Re-exploring the pelvic neuroanatomy from a new perspective and a potential guidance for TaTME: a "bottom-up" approach

Neuro-anatomy of the perineum has gained renewed attention due to its significance in the transanal procedures for rectal cancer (eg TaTME). Surgeons embarking on this technique must have sophisticated knowledge and a precise anatomical understanding of the perineum before proceeding with this reversed rectal approach. We report anatomical observations deriving from a relevant experience in the colorectal surgery field. The collective multicenter experience of the present study is clinically relevant and based on the rectal and transanal resections performed in colorectal centers of excellence from Greece, UK, and Italy over the last 10 years (2011-2020). From the original anatomical and intraoperative observations derived from collective cases operated by this multicenter group of colorectal surgical centers in three European countries, data were retrieved and analyzed in collaboration with specialist researchers of human anatomy and interpreted for their clinical significance and potential use for preoperative planning and intraoperative guidance during TaTME. This descriptive article demonstrates in detail the neurogenic pathways encountered in the perineum and pelvic cavity during transanal procedures. Specific anatomical and topographic implications are also included serving as a guide for colorectal surgeons to perform a nerve-sparing procedure. transanal approach for rectal excision offers new insights into the complex pelvic and perineal neuroanatomy while the procedure itself remains a challenge for surgeons. Preoperative anatomical planning and 3D reconstruction may help in anticipating technical difficulties, resulting in more precise surgical dissections and decreased postoperative complications.

The Anatomical Distribution of the Pudendal Nerve Block Injection: A Cadaveric Study

OBJECTIVE

The objective of this study was to assess the accuracy of commonly used injection locations of the pudendal nerve block by examining the proximity of the injected dye to the pudendal nerve in a cadaveric model.

METHODS

Pudendal block injections at 4 sites were placed transvaginally on 5 cadaveric pelvises. These sites were 1 cm proximal to the ischial spine (black dye), at the ischial spine (red dye), 1 cm distal to the ischial spine (blue dye), and 2 cm lateral and 2 cm distal to the ischial spine (green dye). The cadavers were dissected via a posterior approach.

RESULTS

We measured the shortest distance from the center of the dye-stained tissue to the pudendal nerve. As expected, the injections at the ischial spine (red) resulted in a distribution of dye closest to the pudendal nerve, averaging 3.0 ± 0.95 mm. Dyes at other sites were close to the nerve: 3.1 ± 1.00 mm (black), 3.6 ± 1.14 mm (blue), and 4.05 ± 1.28 mm (green).

CONCLUSIONS

Regardless of the injection site, all dyes were close the pudendal nerve, indicating accuracy. We observed wide variation in the dye distribution even though all injections were performed by the same provider, implicating lack of precision. Based on our findings, we propose that the most effective injection location is at the ischial spine because it is the closest to the pudendal nerve; however, all injections were within 4 mm of the pudendal nerve, suggesting that only 1 to 2 injections may be sufficient.

Pharmacological modulation of voltage-gated sodium (NaV) channels alters nociception arising from the female reproductive tract

Dyspareunia, also known as vaginal hyperalgesia, is a prevalent and debilitating symptom of gynaecological disorders such as endometriosis and vulvodynia. Despite this, the sensory pathways transmitting nociceptive information from female reproductive organs remain poorly characterised. As such, the development of specific treatments for pain associated with dyspareunia is currently lacking. Here, we examined, for the first time, (1) the mechanosensory properties of pelvic afferent nerves innervating the mouse vagina; (2) the expression profile of voltage-gated sodium (NaV) channels within these afferents; and (3) how pharmacological modulation of these channels alters vaginal nociceptive signalling ex vivo, in vitro, and in vivo. We developed a novel afferent recording preparation and characterised responses of pelvic afferents innervating the mouse vagina to different mechanical stimuli. Single-cell reverse transcription-polymerase chain reaction determined mRNA expression of NaV channels within vagina-innervating dorsal root ganglia neurons. Vagina-innervating dorsal root ganglia neuroexcitability was measured using whole-cell patch-clamp electrophysiology. Nociception evoked by vaginal distension was assessed by dorsal horn neuron activation within the spinal cord and quantification of visceromotor responses. We found that pelvic afferents innervating the vagina are tuned to detect various mechanical stimuli, with NaV channels abundantly expressed within these neurons. Pharmacological modulation of NaV channels (with veratridine or tetrodotoxin) correspondingly alters the excitability and mechanosensitivity of vagina-innervating afferents, as well as dorsal horn neuron activation and visceromotor responses evoked by vaginal distension. This study identifies potential molecular targets that can be used to modulate vaginal nociceptive signalling and aid in the development of approaches to manage endometriosis and vulvodynia-related dyspareunia.

Male genital sensation after spinal cord injury: a review

Genital sensation (GS) is an essential component of male sexual function. Genital sensory disturbance (GSD) caused by spinal cord injury (SCI) has a severe impact on the patients' sexual function but has garnered little research focus. Under normal conditions, GS encompasses the erection, ejaculation, sexual arousal, and orgasm courses associated with physiological and psychological responses in male sexual activity. However, in SCI patients, the deficiency of GS makes the tactile stimulation of the penis unable to cause sexual arousal, disturbs the normal processes of erection and ejaculation, and decreases sexual desire and satisfaction. To provide an overview of the contemporary conception and management of male GS after SCI, we review the innervation and sexual function of male GS in this article, discuss the effects of GSD following SCI, and summarize the current diagnosis and treatment of GSD in male SCI patients.

The puborectal continence reflex functions independently of the pudendal nerve

AIM

The ability of patients with poor pudendal nerve function to voluntarily contract their external anal sphincter is limited. However, it is not known whether the condition of the pudendal nerve influences voluntary puborectal muscle contraction. Recently, we described the puborectal continence reflex that maintains faecal continence by involuntary contractions of the puborectal muscle. We aim to investigate whether both voluntary and involuntary contractions of the puborectal muscle are influenced by the condition of the pudendal nerve.

METHOD

We retrospectively analysed 129 adult patients who underwent anorectal function tests at the Anorectal Physiology Laboratory. Anal electrosensitivity was used as a measurement of the pudendal nerve function. Voluntary and involuntary contractions of the puborectal muscle were defined as maximum puborectal muscle contractility and maximum pressure at the level of the puborectal muscle during the balloon retention test.

RESULTS

Voluntary contraction of the puborectal muscle was significantly decreased in patients with pudendal nerve damage (P = 0.002). Involuntary contractions, however, were not associated with the condition of the pudendal nerve (P = 0.63). Multiple linear regression analysis showed that the condition of the pudendal nerve and patients' sex significantly predicted voluntary contraction but not involuntary contraction.

CONCLUSION

Voluntary contractions of the puborectal muscle are significantly decreased in patients with pudendal nerve damage, while involuntary contractions of the puborectal muscle are comparable to those of patients without nerve damage. We conclude that the puborectal continence reflex, which controls involuntary contractions of the puborectal muscle, is not regulated by the pudendal nerve.

Penile Reinnervation Surgery: A Comprehensive Review of the Literature

BACKGROUND

Modern approaches to erectile dysfunction (ED) often entail the use of multimodal medical therapy and surgery; however, with recent advances in microsurgery, new options may exist for patients suffering from ED. This comprehensive review of the literature serves to reevaluate anatomical and physiological principles that mediate erection to improve understanding for reconstructive surgeons hoping to offer new interventions.

METHODS

A search strategy for this review was agreed upon by all authors. Articles were divided into 2 categories - primary and secondary. Primary articles were defined as those in which the anatomy of the pelvis and/or perineum was the primary focus of the article, whereas secondary did not directly focus on anatomic considerations. Select historical texts and textbook chapters were also included to provide well established and critical anatomical evidence for this review.

RESULTS

Several approaches may be used to restore nerve function to treat neurogenic and vasculogenic ED. Somatic sensory loss can be treated by either direct neurorrhaphy or neuroplasty in the location of disruption. Microvascular techniques also exist to improve flow or to repair small vessels injured in the pelvis. Classical approaches to impotence include vein stripping to reduce venous outflow or direct vascularization to improve inflow.

CONCLUSIONS

Postradical prostatectomy ED has been demonstrated to improve with microsurgical interventions. In the coming years, innovation will continue and collaboration between plastic surgeons and urologists will allow us to tackle this common and difficult problem.

Report of an inferior rectal nerve variant arising from the S3 ventral ramus

In surgical approaches to the perineum in general and anal region specifically, considering the possible variations of the inferior rectal nerve is important for the surgeon. Normally, the inferior rectal nerve originates as a branch of the pudendal nerve. However, during routine dissection, a variant of the inferior rectal nerve was found where it arose directly from the third sacral nerve ventral ramus (S3). Many cases have described the inferior rectal nerve arising independently from the sacral plexus, most commonly from the fourth sacral nerve root (S4); however, few cases have reported the inferior rectal nerve arising from S3. Herein, we describe a variant of the inferior rectal nerve in which the nerve arises independently from the sacral plexus.

Lumbopelvic Fixation for Sacral Insufficiency Fracture Presenting with Sphincter Dysfunction

Sacral insufficiency fractures (SIFs) are common in the elderly. In patients with SIF, objective neurological abnormalities such as sphincter dysfunction or leg paresthesia are uncommon. We present a case of SIF accompanied by spinopelvic dissociation with late neurological compromise treated by spinopelvic fixation. A 61-year-old woman presented to our hospital with low back pain without obvious trauma history. She had a past history of eosinophilic granulomatosis with polyangiitis and treatment with steroids. Her low back pain became worse, and she started to have radiating left posterior thigh pain and motor weakness in the left ankle and both great toes with symptoms of stress urinary incontinence, constipation, and loss of anal sensation. Magnetic resonance imaging revealed an H-shaped sacrum fracture. We attributed the neurological symptoms to unstable SIF and performed lumbopelvic fixation. After the surgery, her leg pain and symptoms of stress urinary incontinence improved markedly, as did anal sensation. At a 6-month follow-up, the patient reported no low back pain and she was walking independently without pelvic complaints. CT showed bone union was achieved. Even minimally displaced SIF in patients with osteoporosis can be a cause of bowel and bladder disturbance. Lumbopelvic fixation is a treatment option for SIF with spinopelvic dissociation presenting neurological deficit.

Laparoscopic evaluation of female pelvic neuroanatomy and autonomic plexuses in terms of gynecologic perspective

The nerves located in the deepest areas can be exposed and dissected via laparoscopic magnification. This technological innovation does not only help us to avoid surgery-related complications but also allows us to diagnose the vascular entrapment syndromes. The aim of this article is to demonstrate female neuroanatomy and autonomic plexus via enriched photos and videos to reveal the relationship of the pelvic nervous system with gynecological operations.

Neuropatía del pudendo como causa de dolor pélvico

El síndrome de atrapamiento del nervio pudendo es una de múltiples causas de dolor pélvico crónico. Hemos realizado una revisión de la literatura sobre su presentación clínica, diagnóstico y tratamiento, con el propósito de conocer los detalles más relevantes de una enfermedad que cada vez está siendo más diagnosticada, con el fin de realizar un abordaje precoz desde un punto de vista integral.

A rare and late presentation of pudendal neuralgia in a patient with fibromyalgia after pilates exercises

A 32-year-old female patient was admitted to our clinic about two years ago with complaints of widespread pain, tiredness, fatigue, and insomnia for six months. She was diagnosed with fibromyalgia and initiated medical treatment with the recommendation of aerobic exercises. Her medical history revealed widespread pain disappeared one month after exercising with localized pelvic pain. She had also pain and burning sensation while sitting and lying down. She suffered from severe pain during defecation. Based on her medical history and physical examination findings, the patient was diagnosed with pudendal neuralgia. The patient was put on medical treatment and, then, referred to the anesthesia department due to persistent pain. Computed tomography-guided transgluteal pudendal nerve block was applied by the anesthesiologist. Subsequently, pain disappeared. In conclusion, pudendal neuralgia should be considered in the differential diagnosis in patients with pelvic pain and burning sensation or following compelling exercises.

Anatomy and nerve supply of the pelvic floor

In order to guarantee urinary and fecal continence as well as correct pelvic statics, the perfect neuroanatomical integrity of the pelvic floor muscles is mandatory. As Dickinson stated: “There is no considerable muscle in the body whose form and function are more difficult to understand than those of the levator ani, and about which such nebulous impressions prevail”. Clinical implications of pelvic floor anatomy and nerve supply are evident: a denervation of this muscle group and the consequent muscle dysfunction could result in urinary and/or fecal incontinence, as well as pelvic organ prolapse.

Efficacy of pudendal nerve block for alleviation of catheter-related bladder discomfort in male patients undergoing lower urinary tract surgeries: A randomized, controlled, double-blind trial

BACKGROUND

Catheter-related bladder discomfort (CRBD) to an indwelling urinary catheter is defined as a painful urethral discomfort, resistant to conventional opioid therapy, decreasing the quality of postoperative recovery. According to anatomy, the branches of sacral somatic nerves form the afferent nerves of the urethra and bladder triangle, which deriving from the ventral rami of the second to fourth sacral spinal nerves, innervating the urethral muscles and sphincter of the perineum and pelvic floor; as well as providing sensation to the penis and clitoris in males and females, which including the urethra and bladder triangle. Based on this theoretical knowledge, we formed a hypothesis that CRBD could be prevented by pudendal nerve block.

OBJECTIVE

To evaluate if bilateral nerve stimulator-guided pudendal nerve block could relieve CRBD through urethra discomfort alleviation.

DESIGN AND SETTING

Single-center randomized parallel controlled, double blind trial conducted at West China Hospital, Sichuan University, China.

PARTICIPANTS

One hundred and eighty 2 male adult patients under general anesthesia undergoing elective trans-urethral resection of prostate (TURP) or trans-urethral resection of bladder tumor (TURBT). Around 4 out of 182 were excluded, 178 patients were randomly allocated into pudendal and control groups, using computer-generated randomized numbers in a sealed envelope method. A total of 175 patients completed the study.

INTERVENTION

Pudendal group received general anesthesia along with nerve-stimulator-guided bilateral pudendal nerve block and control group received general anesthesia only.

MAIN OUTCOME MEASURES

Incidence and severity of CRBD; and postoperative VAS score of pain.

RESULTS

CRBD incidences were significantly lower in pudendal group at 30 minutes (63% vs 82%, P = .004), 2 hours (64% vs 90%, P < .000), 8 hours (58% vs 79%, P = .003) and 12 hours (52% vs 69%, P = .028) also significantly lower incidence of moderate to severe CRBD in pudendal group at 30 minutes (29% vs 57%, P < .001), 2 hours (22% vs 55%, P < .000), 8 hours (8% vs 27%, P = .001) and 12 hours (6% vs 16%, P = .035) postoperatively. The postoperative pain score in pudendal group was lower at 30 minutes (P = .003), 2 hours (P < .001), 8 hours (P < .001), and 12 hours (P < .001), with lower heart rate and mean blood pressure. One patient complained about weakness in levator ani muscle.

CONCLUSION

General anesthesia along with bilateral pudendal nerve block decreased the incidence and severity of CRBD for the first 12 hours postoperatively.

Sacral Fractures and Associated Injuries

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to describe the injuries associated with sacral fractures and to analyze their impact on patient outcome.

METHODS

A comprehensive narrative review of the literature was performed to identify the injuries associated with sacral fractures.

RESULTS

Sacral fractures are uncommon injuries that result from high-energy trauma, and that, due to their rarity, are frequently underdiagnosed and mistreated. Only 5% of sacral fractures occur in isolation. Injuries most often associated with sacral fractures include neurologic injuries (present in up to 50% of sacral fractures), pelvic ring disruptions, hip and lumbar spine fractures, active pelvic/ abdominal bleeding and the presence of an open fracture or significant soft tissue injury. Diagnosis of pelvic ring fractures and fractures extending to the lumbar spine are key factors for the appropriate management of sacral fractures. Importantly, associated systemic (cranial, thoracic, and abdominopelvic) or musculoskeletal injuries should be promptly assessed and addressed. These associated injuries often dictate the management and eventual outcome of sacral fractures and, therefore, any treatment algorithm should take them into consideration.

CONCLUSIONS

Sacral fractures are complex in nature and often associated with other often-missed injuries. This review summarizes the most relevant associated injuries in sacral fractures and discusses on their appropriate management.

Pudendal nerve and branch neuropathy: magnetic resonance neurography evaluation

Pudendal neuralgia is being increasingly recognized as a cause of chronic pelvic pain, which may be related to nerve injury or entrapment. Due to its complex anatomy and branching patterns, the pudendal nerve abnormalities are challenging to illustrate. High resolution 3 T magnetic resonance neurography is a promising technique for the evaluation of peripheral neuropathies. In this article, the authors discuss the normal pudendal nerve anatomy and its variations, technical considerations of pudendal nerve imaging, and highlight the normal and abnormal appearances of the pudendal nerve and its branches with illustrative case examples.

Magnetic Resonance Neurography of the Pelvic Nerves

Chronic pelvic pain syndrome is commonly caused by nerve injury, inflammation, or entrapment. Owing to the complex anatomy and branching patterns of pelvic nerves, pelvic neuropathies are often difficult to illustrate and diagnose. High-resolution 3-T magnetic resonance neurography is a promising technique for the evaluation of peripheral neuropathy. In this article, the authors discuss the normal anatomy of major pelvic nerves, technical considerations of high-resolution imaging, and normal and abnormal imaging appearances with relevant case examples.

Prevention of catheter-related bladder discomfort - pudendal nerve block with ropivacaine versus intravenous tramadol: study protocol for a randomized controlled trial

Background

Catheter-related bladder discomfort (CRBD) is a common distressing symptom complex during the postoperative period, especially after urologic procedures with a relatively greater size urinary catheter. In this study, we will enroll male patients undergoing elective prostate surgery with urinary catheterization under general anesthesia, and we will compare the efficacy of pudendal nerve block (PNB) and intravenous tramadol in CRBD prevention.

Methods/design

This trial is a prospective, randomized controlled trial that will test the superiority of bilateral PNB with 0.33 % ropivacaine compared with intravenous tramadol 1.5 mg/kg for CRBD prevention. A total of 94 male patients undergoing elective prostate surgery with urinary catheterization after anesthesia induction will be randomized to receive either bilateral PNB with 0.33 % ropivacaine (the PNB group) or intravenous tramadol 1.5 mg/kg (the tramadol group) after the completion of surgery. The primary outcome is the incidence of CRBD. The most important secondary outcome is the severity of postoperative CRBD, and other secondary outcomes include Numeric Rating Scale (NRS) score for postoperative pain; incidence of postoperative side effects such as postoperative nausea/vomiting, sedation, dizziness, and dry mouth; postoperative requirement for tramadol as a rescue treatment for CRBD and sufentanil as a rescue analgesic for postoperative pain; and NRS score for acceptance of an indwelling urinary catheter.

Discussion

This trial is planned to test the superiority of PNB with 0.33 % ropivacaine compared with intravenous tramadol 1.5 mg/kg. It may provide a basis for a new clinical practice for the prevention of CRBD.

Trial registration

ClinicalTrials.gov identifier NCT02683070. Registered on 11 February 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1575-y) contains supplementary material, which is available to authorized users.

Recurrent lumbosacral herpes simplex virus infection

We present the case of a 54-year-old white woman with episodic lumbosacral lesions that she had been treating as psoriasis. Evaluation revealed classic herpes simplex virus (HSV) infection. The discussion reviews the significance and potential complications of recurrent lumbosacral HSV infection.

Topography and landmarks for the nerve supply to the levator ani and its relevance to pelvic floor pathologies

The aim of this study was to explore the anatomical variations of the nerve to the levator ani (LA) and to relate these findings to LA dysfunction. One hundred fixed human female cadavers were dissected using transabdominal, gluteal, and perineal approaches, resulting in two hundred dissections of the sacral plexus. The pudendal nerve and the sacral nerve roots were traced from their origin at the sacral foramina to their termination. All nerves contributing to the innervation of the LA were considered to be the nerve to the LA. Based on the spinal nerve components, the nerve to the LA was classified into the following categories: 50% (n = 100) originated from S4 and S5 (type I); 19% (n = 38) originated from S5 (type II); 16% (n = 32) originated from S4 (type III); 11% (n = 22) originated from S3 and S4 (type IV); 4% (n = 8) originated from S3, S4, and S5 (type V). Two patterns of nerve termination were observed. In 42% of specimens, the nerve to the LA penetrated the coccygeus muscle and assumed an external position along the inferior surface of the LA muscle. In the remaining 58% of specimens, the nerve crossed the superior surface of the coccygeus muscle and continued along the superior surface of the iliococcygeus muscle. Damage to the nerve to LA has been associated with various pathologies. In order to minimize injuries during surgical procedures, a thorough understanding of the course and variations of the nerve to the LA is extremely important.

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.

Minimizing Stimulus Current in a Wearable Pudendal Nerve Stimulator Using Computational Models

After spinal cord injury, functions of the lower urinary tract may be disrupted. A wearable device with surface electrodes which can effectively control the bladder functions would be highly beneficial to the patients. A trans-rectal pudendal nerve stimulator may provide such a solution. However, the major limiting factor in such a stimulator is the high level of current it requires to recruit the nerve fibers. Also, the variability of the trajectory of the nerve in different individuals should be considered. Using computational models and an approximate trajectory of the nerve derived from an MRI study, it is demonstrated in this paper that it may be possible to considerably reduce the required current levels for trans-rectal stimulation of the pudendal nerve compared to the values previously reported in the literature. This was corroborated by considering an ensemble of possible and probable variations of the trajectory. The outcome of this study suggests that trans-rectal stimulation of the pudendal nerve is a plausible long term solution for treating lower urinary tract dysfunctions after spinal cord injury.

The Pudendal Nerve and Its Branches in Relation to Richter's Procedure

OBJECTIVE

Variations in the branching pattern of the pudendal nerve (PN) have been described in the literature. This study investigated these variations in order to comment on a safe area for the placement of a Richter's stitch.

METHODS

Richter's procedure was performed on nine unembalmed female cadavers and followed by dissection. PN dissections were done on another 20 embalmed female cadavers. Variations in the branching pattern of the PN were noted and the distance between the Richter's stitch placed and the PN/or the inferior rectal nerve (IRN) measured.

RESULTS

The IRN entered the gluteal region as a separate structure in 6/29 cases. The separate IRN was found to pass between 4.1 and 14.45 mm medial to the ischial spine in 18/29 cases. In one case, the Richter's stitch was found to pierce the IRN. The distance between the stitch and the PN and/or the IRN ranged from 0 to 17.8 mm.

CONCLUSIONS

To minimize the risk of nerve damage or entrapment, the Richter's stitch should be placed >20 mm from the ischial spine. This recommended area should be revised for different population groups, as variations might exist between groups.

Percutaneous CT-guided cryoablation for the treatment of refractory pudendal neuralgia

PURPOSE

To evaluate the safety and efficacy of percutaneous CT-guided cryoablation of the pudendal nerve for the treatment of refractory pudendal neuralgia.

MATERIALS AND METHODS

Eleven patients were selected to undergo percutaneous CT-guided cryoablation of the pudendal nerve based on established diagnostic criteria. Brief Pain Inventory questionnaires were administered prior to the procedure, during the immediate 24 h post procedure, and 45 days and 6 months following the procedure.

RESULTS

Prior to treatment, the average level of pain on a scale from 0 (no pain) to 10 (worst pain imaginable) was 7.6, with pain described as "burning" (80%), "pulling" (37.5%), "crushing" (50%), "pressure" (84.5%), "throbbing" (50%), "knife-life" (52%), and "other" (60%). At 24 h, 45 days, and 6 months post-treatment, pain intensity dropped to 2.6, 3.5, and 3.1, respectively (p < 0.005). There were no procedure-related complications.

CONCLUSIONS

CT-guided percutaneous cryoablation may represent a safe and efficacious option for selected patients with refractory pudendal neuralgia.

Electrical stimulation for the treatment of lower urinary tract dysfunction after spinal cord injury

Electrical stimulation for bladder control is an alternative to traditional methods of treating neurogenic lower urinary tract dysfunction (NLUTD) resulting from spinal cord injury (SCI). In this review, we systematically discuss the neurophysiology of bladder dysfunction following SCI and the applications of electrical stimulation for bladder control following SCI, spanning from historic clinical approaches to recent pre-clinical studies that offer promising new strategies that may improve the feasibility and success of electrical stimulation therapy in patients with SCI. Electrical stimulation provides a unique opportunity to control bladder function by exploiting neural control mechanisms. Our understanding of the applications and limitations of electrical stimulation for bladder control has improved due to many pre-clinical studies performed in animals and translational clinical studies. Techniques that have emerged as possible opportunities to control bladder function include pudendal nerve stimulation and novel methods of stimulation, such as high frequency nerve block. Further development of novel applications of electrical stimulation will drive progress towards effective therapy for SCI. The optimal solution for restoration of bladder control may encompass a combination of efficient, targeted electrical stimulation, possibly at multiple locations, and pharmacological treatment to enhance symptom control.

Genital sensation in women with pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

The objective was to compare vaginal and clitoral sensory thresholds in women with pelvic organ prolapse and women with normal pelvic anatomy.

METHODS

Quantitative sensory thresholds for warm, cold, and vibratory sensations were measured at the vagina and clitoral area of women with pelvic organ prolapse, pelvic organ prolapse quantification (POP-Q) stage II or higher (study group) and of women without prolapse, POP-Q stage ≤ I (control group). The quantitative sensory tests were performed with a thermal and vibration Genito-Sensory Analyzer, at the distal third of the anterior and posterior vaginal wall and at the clitoral area. Warm stimuli were used to evaluate unmyelinated C-fibers; cold stimuli for thinly myelinated A-delta; and vibratory stimuli for large A-beta fibers. Independent Student's t test and Chi-squared test of association were used for analysis of continuous and categorical parameters respectively.

RESULTS

Overall, 66 women, 22 with median POP-Q stage III (range: II-IV) and 44 with POP-Q stage I (range: 0-I), participated in the study. There were no statistically significant differences between the two groups regarding the characteristics examined (health status, medical history, and age). In all regions examined, mean thresholds for vibratory and warm stimuli were significantly higher and mean thresholds for cold stimuli significantly lower in the group with prolapse.

CONCLUSION

Women with pelvic organ prolapse exhibited lower sensitivity in the genital area to vibratory and thermal stimuli than did women without prolapse. Our findings suggest that a neuropathic sensory deficit in the area of the genitalia might be associated with prolapse.