Robot assisted exploration of the Alcock canal: a novel surgical technique.

OBJECTIVE: To demonstrate a safe and reproducible surgical approach to the Alcock canal with a full decompression of the pudendal nerve. SETTING: Pudendal neuralgia, a condition causing debilitating pelvic pain, is traditionally managed through a trans-gluteal incision.1-2 This surgical approach offers limited visualization and ability for nerve decompression.3 With the current technique, a full exposure and decompression of the pudendal nerve was achieved. PARTICIPANTS: A 44-year-old para 2 with symptoms of left pudendal neuralgia. INTERVENTIONS: A 44-year-old para 2 presented with burning vaginal pain radiating to the left groin that was aggravated with sitting. She underwent a robotic-assisted left sacrospinous ligament transection and fasciotomy of the obturator internus muscle for suspected pudendal neuralgia. The surgery was performed with three robotic ports using the daVinci® Xi robotic system. CONCLUSION: With the enhanced access to the pudendal nerve provided by the novel surgical technique demonstrated in this study, a more comprehensive nerve decompression can be performed. This technique was successfully applied to a patient with pudendal neuralgia. There were no immediate intra-operative or post-operative complications. In short-term follow-up, the patient had significant relief of preoperative symptoms. While all surgical procedures for pudendal neuralgia have a risk of pudendal nerve and vessel injury,4 the presented technique has the potential to limit these risks by providing an enhanced view of the relevant anatomy. Future adaptation and refinement of this technique may contribute to the advancement of the surgical management of pudendal neuralgia.

The pudendal syndrome: A photo essay of nerve compression damage visualized at neurolysis in patients with chronic neuropathic pelvic pain.

AIMS: (1) To use intraoperative photographs to visualize and explain pudendal nerve compressions and anatomical variations of compression sites in patients with chronic pelvic pain. (2) To emphasize the diagnostic importance of sensory examination with a safety pin at the six pudendal nerve branches in all patients with chronic pelvic pain; the dorsal nerves (penis or clitoris; the perineal nerves; and the inferior rectal nerves). METHODS: Between 2003 and 2014, "definite" pudendal neuropathy was diagnosed by examination and with two neurophysiologic tests. Neurolysis, via a transgluteal approach, was recommended only after 14 weeks of conservative care failed to adequately improve symptoms and validated symptom scores. Photographs of surgical findings were culled for their educational impact. An illustration of each photo clarifies the surgical anatomy. RESULTS: The transgluteal incision permits access to pudendal anatomy and compression sites from the subpiriformis area through the interligamentary space and the pudendal canal (Alcock canal). Compressions were acquired or congenital and severity varied significantly. Pinprick sensory testing diagnoses pudendal neuropathy in 92% of both genders. Mid-nerve compression occurred commonly between the sacrotuberous and sacrospinous ligaments less frequently in the Alcock canal, but also at aberrant pathways, for example, between layers of the sacrotuberous ligament; a separate inferior rectal nerve passing through the sacrospinous ligament; at an anomalous lateral pathway posterior to the ischial spine. The results of international surgeons are discussed. CONCLUSIONS: Decompression surgery was recommended in approximately 35% of patients in this practice, when pudendal neuropathy (pudendal syndrome), did not respond to two conservative levels of treatment: (1) nerve protection and medications and, (2) a series of three pudendal nerve perineural injections given at 4-week intervals. Significant nerve compression is consistently observed. Pathophysiology includes axonopathy from ischemia and demyelination. Neuropathy is readily diagnosed using a pinprick sensory examination of six pudendal nerve branches. Monitoring with the National Institutes of Health Chronic Prostatitis Symptom Index records cures >13 years.

Lumbosacral plexus and pudendal nerve magnetic resonance tractography: A systematic review of the clinical applications for pudendal neuralgia.

Diffusion tensor imaging (DTI) is commonly used to establish three-dimensional mapping of white-matter bundles in the supraspinal central nervous system. DTI has also been the subject of many studies on cranial and peripheral nerves. This non-invasive imaging technique enables virtual dissection of nerves in vivo and provides specific measurements of microstructural integrity. Adverse effects on the lumbosacral plexus may be traumatic, compressive, tumoral, or malformative and thus require dedicated treatment. DTI could lead to new perspectives in pudendal neuralgia diagnosis and management. We performed a systematic review of all articles or posters reporting results and protocols for lumbosacral plexus mapping using the DTI technique between January 2011 and December 2023. Twenty-nine articles published were included. Ten studies with a total of 351 participants were able to track the lumbosacral plexus in a physiological context and 19 studies with a total of 402 subjects tracked lumbosacral plexus in a pathological context. Tractography was performed on a 1.5T or 3T MRI system. DTI applied to the lumbosacral plexus and pudendal nerve is feasible but no microstructural normative value has been proposed for the pudendal nerve. The most frequently tracking parameters used in our review are: 3T MRI, b-value of 800 s/mm2, 33 directions, 3 × 3 × 3 mm3, AF threshold of 0.1, minimum fiber length of 10 mm, bending angle of 30°, and 3DT2 TSE anatomical resolution. Increased use of DTI could lead to new perspectives in the management of pudendal neuralgia due to entrapment syndrome, whether at the diagnostic, prognostic, or preoperative planning level. Prospective studies of healthy subjects and patients with the optimal acquisition parameters described above are needed to establish the accuracy of MR tractography for diagnosing pudendal neuralgia and other intrapelvic nerve entrapments.

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.

Efficacy of ganglion impar block combined with pudendal nerve pulsed radiofrequency for pudendal neuralgia management-a randomized clinical trial.

BACKGROUND: Pudendal neuralgia is a chronic and debilitating condition. Its prevalence ranges from 5 to 26%. Currently, therapeutic approaches to treat pudendal neuralgia include patient education, medication management, psychological and physical therapy, and procedural interventions, such as nerve block, trigger point injections, and surgery. Drug therapy has a limited effect on pain relief. A pudendal nerve block may cause a significant decrease in pain scores for a short time; however, its efficacy significantly decreases over time. In contrast, pudendal nerve pulsed radiofrequency can provide pain relief for 3 months, and ganglion impar block has been widely used for treating chronic perineal pain and chronic coccygodynia. This study aimed to determine the efficacy and safety of monotherapy (pudendal nerve pulsed radiofrequency) and combination therapy (pudendal nerve pulsed radiofrequency plus ganglion impar block) in patients with pudendal neuralgia. METHODS: This randomized, controlled clinical trial will include 84 patients with pudendal neuralgia who failed to respond to drug or physical therapy. Patients will be randomly assigned into one of the two groups: mono or combined treatment groups. The primary outcome will be a change in pain intensity measured using the visual analog scale. The secondary outcomes will include a Self-Rating Anxiety Scale score, Self-Rating Depression Scale score, the use of oral analgesics, the Medical Outcomes Study Health Survey Short Form-36 Item score, and the occurrence of adverse effects. The study results will be analyzed using intention-to-treat and per-protocol analyses. Primary and secondary outcomes will be evaluated between the mono and combined treatment groups. Subgroup analyses will be conducted based on the initial ailment, age, and baseline pain intensity. The safety of the treatment will be assessed by monitoring adverse events, which will be compared between the two groups. DISCUSSION: This study protocol describes a randomized, controlled clinical trial to determine the efficacy and safety of mono and combination therapies in patients with pudendal neuralgia. The study results will provide valuable information on the potential benefits of this combination therapy and contribute to the development of more effective and safer treatments for patients with pudendal neuralgia. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2200061800).

Fluoroscopy-Guided Transgluteal Pudendal Nerve Block for Pudendal Neuralgia: A Retrospective Case Series.

Background/Objective: Pudendal neuralgia is a distressing condition that presents with pain in the perineum. While a positive anesthetic pudendal nerve block is one of the essential criteria for diagnosing this condition, this block can also provide a therapeutic effect for those afflicted with pudendal neuralgia. There are multiple ways in which a pudendal nerve block can be performed. The objective of this study is to share our results and follow-up of fluoroscopy-guided transgluteal pudendal nerve blocks. Methods: This is a retrospective case series. Included were 101 patients who met four out of the five Nantes criteria (pain in the anatomical territory of the pudendal nerve, pain worsened by sitting, pain that does not wake the patient up at night, and no objective sensory loss on clinical examination) who did not respond to conservative treatment and subsequently underwent a fluoroscopy-guided transgluteal pudendal nerve block. Therapeutic success was defined as a 30% or greater reduction in pain. Success rates were calculated, and the duration over which that success was sustained was recorded. Results: For achieving at least 30% relief of pain, using worst-case analysis, the success rate at two weeks was 49.4% (95% CI: 38.5%, 60.3%). In addition to pain relief, patients experienced other therapeutic benefits, such as reductions in medication use and improvements in activities of daily living. Conclusions: Fluoroscopy-guided transgluteal pudendal nerve block appears to be effective in patients who have pudendal neuralgia that is resistant to conservative therapy, with good short-term success.

Accuracy of augmented reality-guided needle placement for pulsed radiofrequency treatment of pudendal neuralgia: a pilot study on a phantom model.

Background: Pudendal neuralgia (PN) is a chronic neuropathy that causes pain, numbness, and dysfunction in the pelvic region. The current state-of-the-art treatment is pulsed radiofrequency (PRF) in which a needle is supposed to be placed close to the pudendal nerve for neuromodulation. Given the effective range of PRF of 5 mm, the accuracy of needle placement is important. This study aimed to investigate the potential of augmented reality guidance for improving the accuracy of needle placement in pulsed radiofrequency treatment for pudendal neuralgia. Methods: In this pilot study, eight subjects performed needle placements onto an in-house developed phantom model of the pelvis using AR guidance. AR guidance is provided using an in-house developed application on the HoloLens 2. The accuracy of needle placement was calculated based on the virtual 3D models of the needle and targeted phantom nerve, derived from CBCT scans. Results: The median Euclidean distance between the tip of the needle and the target is found to be 4.37 (IQR 5.16) mm, the median lateral distance is 3.25 (IQR 4.62) mm and the median depth distance is 1.94 (IQR 7.07) mm. Conclusion: In this study, the first method is described in which the accuracy of patient-specific needle placement using AR guidance is determined. This method could potentially improve the accuracy of PRF needle placement for pudendal neuralgia, resulting in improved treatment outcomes.

Pudendal nerve blockade for persistent genital arousal disorder (PGAD): A clinical review and case report.

BACKGROUND: Persistent genital arousal disorder (PGAD) is a condition characterized by unwanted and potentially painful genital sensations or spontaneous orgasms without stimulation. We present a case of a 55-year-old woman with refractory genital arousal disorder that was treated with serial pudendal nerve blocks. CASE: RW is a 55-year-old woman with chronic pelvic pain, pudendal neuralgia, MDD, SI, GAD, CRPS, and persistent genital arousal disorder for 11 years. Her PGAD was refractory to conservative management, physical therapy, and bilateral clitoral artery embolization. We performed bilateral pudendal nerve blocks with Kenalog and Bupivacaine, which provided almost complete relief for 2-3 months. We performed a bilateral pudendal nerve radiofrequency ablation; however, there was minimal benefit. RW continues to have significant relief with serial pudendal nerve blocks. SUMMARY AND CONCLUSION: Persistent genital arousal disorder is often refractory to medication and physical therapy requiring significant intervention such as entrapment surgery or artery embolization. Our case demonstrates pudendal nerve blocks as a potential treatment modality with minimal side effects.

Management of pudendal neuralgia with electrical stimulation. A systematic review.

INTRODUCTION AND OBJECTIVE: Pudendal neuralgia is a severely intense, painful, neuropathic condition, involving the dermatome of the pudendal nerve (S2, S3, S4). The diagnosis is complex and usually takes many years to be made. Techniques that use electrical current have been shown to decrease pain and improve quality of life in patients with this condition. The aim of this review was to analyze the existing literature on the effects of electrical current in the treatment of patients with pudendal neuralgia. MATERIAL AND METHODS: A literature search was carried out in PubMed, Cinahl, Medline, Cochrane Library, ENFISPO, PEDro, Scopus and Web of Science databases, using the search terms "Electric Stimulation Therapy", "pudendal neuralgia" and "pudendal nerve entrapment". RESULTS: The most frequently repeated intervention is pulsed radiofrequency. Other techniques used are transcutaneous electrical nerve stimulation, pulsed electromagnetic field therapy and neuromodulation. All studies show significant improvement in pain, analgesic intake, depression-anxiety or quality of life. CONCLUSIONS: The application of electrical current seems to be effective in the management of pudendal neuralgia. The scientific evidence is scarce, of poor methodological quality, and its use is based on the efficacy demonstrated in other indications of chronic pain.

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.

Ischiorectal Approach to Cryoablation of the Pudendal Nerve Using a Handheld Device: A Report of Two Cases.

The pudendal nerve is situated deep within the pelvis and is a challenge to target for pain interventions due to the theoretical risk of incontinence with manipulation. The management of pudendal neuralgia using cryoablation is currently limited as it has historically required computed tomography (CT) guidance by interventional radiologists. Through this report, we describe a safe, reproducible, ischiorectal fossa approach to pudendal nerve cryoablation with a handheld device utilizing anatomical landmarks, nerve stimulation, and fluoroscopy. Two patients with longstanding pelvic pain and positive response to diagnostic pudendal nerve blocks underwent bilateral cryoablation of the pudendal nerves. This procedure was performed with the patients in prone positioning and percutaneous insertion of a cryoablation probe medial to the ischial tuberosity and lateral to the rectum. Correct positioning on the pudendal nerve was achieved with nerve stimulation eliciting visible anal sphincter contraction, and fluoroscopic imaging of the probe relative to the ischial spine. The probe was set to -88 Celsius for 108 seconds and a total of two cycles were performed. Pain reduction was reported for 3-4 months and repeat cryoablation was similarly efficacious with no evidence of incontinence. This technique, we believe minimizes risks and simplifies cryoablation to be performed on an outpatient basis by more pain physicians.

Association of Postless Distraction in Hip Arthroscopy With Decreased Postoperative Groin Numbness.

BACKGROUND: Patients undergoing hip arthroscopy performed with perineal post distraction may experience postoperative nerve and soft tissue complications related to the perineal post. PURPOSE: To compare rates of postoperative numbness in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with postless distraction and perineal post distraction methods. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective review of prospectively collected data was performed on patients who underwent hip arthroscopy for FAIS, with postless distraction and perineal post distraction methods. Medical records were reviewed for patient characteristics, radiographic data, and operative data. Traction force data were collected on all patients prospectively using a previously validated method. Data on postoperative numbness (presence/absence and regionality) were collected prospectively at routine postoperative follow-ups (6-week and 3-month postoperative clinic visits). RESULTS: Overall, 195 patients were included, with 94 patients (mean age, 30.4 years) in the postless distraction cohort and 101 patients (mean age, 31.9 years) in the post distraction cohort. The overall numbness rates were 29 of 94 (30.9%) in the postless distraction group and 45 of 101 (44.6%) in the post distraction group (P = .068). Rates of postoperative groin numbness were 1 of 94 (1.1%) in the postless distraction group and 19 of 101 (18.8%) in the post distraction group (P < .001). Multivariate analysis for postoperative groin numbness demonstrated post distraction (odds ratio [OR], 16.5; P = .022) and traction time (OR, 1.7; P = .020) to be statistically significant variables. In subgroup analysis of the post distraction group, traction time (P = .015), but not holding (P = .508) or maximum traction force (P = .665), reached statistical significance in patients who developed postoperative groin numbness. CONCLUSION: Postless distraction hip arthroscopy demonstrated a statistically significantly lower rate of groin numbness rates in comparison with a traditional perineal post distraction method. In the post distraction group, traction time was significantly higher in patients who developed postoperative groin numbness than in those who did not.

YouTube and pudendal neuralgia: Is it a good source of information for patients?

OBJECTIVE: This study aims to identify the shortcomings and quality content of YouTube videos and its effectiveness as a source of patient information on pudendal neuralgia treatment. METHODS: A search was conducted on YouTube using the words "pudendal neuralgia physical therapy," "medications for pudendal neuralgia," "pudendal nerve block," "pudendal neuralgia surgery," and "alternative treatments for pudendal neuralgia." The results were analyzed based on the source, general descriptive statistics, the intended audience, and five content areas. The DISCERN scoring system was used to evaluate the quality of videos. RESULTS: After the search, 73 videos met the inclusion criteria for further analysis. The majority of these videos (61.64%) were intended to target the general population, whereas a smaller percentage were identified as professional (41.10%) or targeted for physicians (35.62%). From the videos included, 10 (13.70%) described treatment options in a balanced and evidence-based manner. The higher DISCERN score positively correlated with the presence of this last content criterion. With a total DISCERN mean score of 35.42, a significant proportion of the videos (41.10%) were rated very poor. The remaining videos were classified as poor (23.29%), fair (19.18%), good (8.22%), and excellent (8.22%). CONCLUSION: The quality of the information included in YouTube videos regarding pudendal neuralgia treatment was considered generally poor. Healthcare providers must recognize the potential influence of this platform on patients' understanding of pudendal neuralgia treatment. There is a need for additional research and randomized studies regarding YouTube content about this condition.

First case-series of robot-assisted pudendal nerve release: technique and outcomes.

OBJECTIVE: Pudendal Nerve Entrapment (PNE) may determine chronic pelvic pain associated with symptoms related to its innervation area. This study aimed to present the technique and report the outcomes of the first series of robot-assisted pudendal nerve release (RPNR). PATIENTS AND METHODS: 32 patients, who were treated with RPNR in our centre between January 2016 and July 2021, were recruited. Following the medial umbilical ligament identification, the space between this ligament and the ipsilateral external iliac pedicle is progressively dissected to identify the obturator nerve. The dissection medial to this nerve identifies the obturator vein and the arcus tendinous of the levator ani, which is cranially inserted into the ischial spine. Following the cold incision of the coccygeous muscle at the level of the spine, the sacrospinous ligament is identified and incised. The pudendal trunk (vessels and nerve) is visualized, freed from the ischial spine and medially transposed. RESULTS: The Median duration of symptoms was 7 (5, 5-9) years. The median operative time was 74 (65-83) minutes. The median length of stay was 1 (1-2) days. There was only a minor complication. At 3 and 6 months after surgery, a statistically significant pain reduction has been encountered. Furthermore, the Pearson correlation coefficient reported a negative relationship between the duration of pain and the improvement in NPRS score, - 0.81 (p = 0.01). CONCLUSIONS: RPNR is a safe and effective approach for the pain resolution caused by PNE. Timely nerve decompression is suggested to enhance outcomes.

Dorsal Root Ganglion Stimulation Therapy for Refractory Idiopathic Pudendal Neuralgia.

Dorsal root ganglion stimulation is a relatively new treatment option for chronic pain conditions such as pudendal neuralgia, which is a chronic pain condition affecting the pudendal nerve in the pelvic region. Pudendal neuralgia is a debilitating condition that can significantly affect the patient's quality of life. In dorsal root ganglion stimulation, a small device is implanted that delivers electrical impulses to the dorsal root ganglion to modulate pain signals coming from the pudendal nerve. The procedure is considered investigational and has been investigated in case series and case reports with promising results. However, more research is needed to fully understand its safety and effectiveness. This case report highlights the potential of dorsal root ganglion stimulation as a treatment option for pudendal neuralgia and the need for further research to establish it as a standard treatment option.

Clinical usefulness of quantitative thermal sensory testing in the diagnosis and surgical treatment of women with pudendal neuropathy.

BACKGROUND: The aim of this study, conducted on women with pudendal neuropathy, was to evaluate the usefulness of quantitative thermal sensory testing (QTST) in the diagnosis, surgical management, and prognosis of the disease. METHODS: The study was conducted on 90 women with pudendal neuropathy. QTST in pudendal nerve sensory innervation territory was realized before and more than 24 months after operative pudendoscopy on most patients. Cold and warm thresholds were evaluated together with a search for qualitative anomalies. The diagnostic value of QTST was assessed by comparing baseline data with normative values previously derived from 41 presumably healthy women. The effect of operative pudendoscopy on thermal sensitivity was tested by comparing preoperative and postoperative measurements. Assessment of the long-term prognostic value of QTST was based on "surgical success" defined as a VAS pain level less than 4 at least 2 years after surgery. RESULTS: The existence of qualitative anomalies, like anesthesia, allodynia, dysesthesia, radiation, and dyslocalization, was clearly indicative of pudendal neuropathy. The presence of after sensation and "out of limit" values of skin temperature and cold detection threshold were also helpful for diagnosing the disease. Surgery reduced qualitative anomalies but had no positive effect on QTST thresholds. QTST measurements had no real prognostic value but other factors like constipation and abnormal perineal descent were predictive of surgical success. CONCLUSION: For women with pudendal neuropathy, QTST can be considered a useful, non-invasive tool in the diagnosis, and management of the disease, but it cannot predict satisfactorily long-term outcome of operative pudendoscopy.

Anatomical description of the perforating cutaneous nerve.

BACKGROUND: The perforating cutaneous nerve/perforating nerve of the sacrotuberous ligament is rarely observed. It usually arises from the posterior division of the sacral plexus or the pudendal nerve and perforates the sacrotuberous ligament. The anatomy of this nerve and its variants is poorly described in the literature, but there are data indicating its role in pudendal neuralgia. MATERIALS AND METHODS: Herein, we present an anatomical study of six formalin-fixed cadavers with descriptions of the topography of spinal nerves S2-S4, the pudendal bundle, the perforating cutaneous nerve and the sacrotuberous ligament. RESULTS: We found three perforating cutaneous nerves and described each of them in detail, with measurements of length and width, and point of perforation of the sacrotuberous ligament. CONCLUSIONS: We distinguished three types of perforating cutaneous nerve on the basis of our findings and previous publications; two of the three types were observed in our study.

Unidentified Branches of the Posterior Femoral Cutaneous Nerve and Persistent Neuropathy.

The posterior femoral cutaneous nerve (PFCN) is an extensive nerve with numerous collateral branches which provide cutaneous innervation to 2/3rds of the posterior thigh, the infragluteal fold, as well as the lateral anal region, scrotum, and labia majora through its inferior cluneal and pudendal nerve branches. It has been noted in multiple studies that patients can experience persistent PFCN neuropathy after surgery for decompression of known collateral branches. In this study, we used 17 formaldehyde (7 male and 10 female) perfused cadavers obtained from Hershey Medical Center's donor program to study the branching patterns of the PFCN. As a result, we found that 41% of individuals have an unidentified proximal branch of PFCN that recurs over the inferolateral border of the gluteus maximus, suggesting other areas of potential compression or nerve entrapment that could lead to persistent PFCN neuropathy that's not improved after treatment for sciatic, pudendal, or inferior cluneal neuralgia. We hope these findings allow clinicians to modify current surgical techniques and improve patients' post-operative quality of life.

Diagnosis and treatment of pudendal and inferior cluneal nerve entrapment syndrome: a narrative review.

AIM: Pudendal and inferior cluneal nerve entrapment can cause a neuropathic pain syndrome in the sensitive areas innervated by these nerves. Diagnosis is challenging and patients often suffer several years before diagnosis is made. The purpose of the review was to inform healthcare workers about this disease and to provide a basis of anatomy and physiopathology, to inform about diagnostic tools and invasive or non-invasive treatment modalities and outcome. METHODS: A description of pudendal and inferior cluneal nerve anatomy is given. Physiopathology for entrapment is explained. Diagnostic criteria are described, and all non-invasive and invasive treatment options are discussed. RESULTS: The Nantes criteria offer a solid basis for diagnosing this rare condition. Treatment should be offered in a pluri-disciplinary setting and consists of avoidance of painful stimuli, physiotherapy, psychotherapy, pharmacological treatment led by tricyclic antidepressants and anticonvulsants. Nerve blocks are efficient at short term and serve mainly as a diagnostic tool. Pulsed radiofrequency (PRF) is described as a successful treatment option for pudendal neuralgia in patients non-responding to non-invasive treatment. If all other treatments fail, surgery can be offered. Different surgical procedures exist but only the open transgluteal approach has proven its efficacy compared to medical treatment. The minimal-invasive ENTRAMI technique offers the possibility to combine nerve release with pudendal neuromodulation. CONCLUSIONS: Pudendal and inferior cluneal nerve entrapment syndrome are a challenge not only for diagnosis but also for treatment. Different non-invasive and invasive treatment options exist and should be offered in a pluri-disciplinary setting.

Novel anatomical findings with implications on the etiology of the piriformis syndrome.

PURPOSE: The cause of the piriformis-related pelvic and extra-pelvic pain syndromes is still not well understood. Usually, the piriformis syndrome is seen as extra-pelvic sciatica caused by the entrapment of the sciatic nerve by the piriformis in its crossing through the greater sciatic foramen. However, the piriformis muscle may compress additional nerve structures in other regions and cause idiotypic pelvic pain, pelvic visceral pain, pudendal neuralgia, and pelvic organ dysfunction. There is still a lack of detailed description of the muscle origin, topography, and its possible relationships with the anterior branches of the sacral spinal nerves and with the sacral plexus. In this research, we aimed to characterize the topographic relationship of the piriformis with its surrounding anatomical structures, especially the anterior branches of the sacral spinal nerves and the sacral plexus in the pelvic cavity, as well as to estimate the possible role of anatomical piriformis variants in pelvic pain and extra-pelvic sciatica. METHODS: Human cadaveric material was used accordingly to the Swiss Academy of Medical Science Guidelines adapted in 2021 and the Federal Act on Research involving Human Beings (Human Research ACT, HRA, status as 26, May 2021). All body donors gave written consent for using their bodies for teaching and research. 14 males and 26 females were included in this study. The age range varied from 64 to 97 years (mean 84 ± 10.7 years, median 88). RESULTS: three variants of the sacral origin of the piriformis were found when referring to the relationship between the muscle and the anterior sacral foramen. Firstly, the medial muscle origin pattern and its complete covering of the anterior sacral foramen by the piriformis muscle is the most frequent anatomical variation (43% in males, 70% in females), probably with the most relevant clinical impact. This pattern may result in the compression of the anterior branches of the sacral spinal nerves when crossing the muscle. CONCLUSIONS: These new anatomical findings may provide a better understanding of the complex piriformis and pelvic pain syndromes due to compression of the sacral spinal nerves with their somatic or autonomous (parasympathetic) qualities when crossing the piriformis.