What is the place of electroneuromyographic studies in the diagnosis and management of pudendal neuralgia related to entrapment syndrome?

Advancing the diagnosis and management of pudendal nerve entrapment: The role of neurophysiological studies and imaging-guided infiltrations

PURPOSE

Pudendal nerve entrapment (PNE) diagnosis is not standardized. This leads to diagnosis delays, impacting quality of life and therapeutic outcomes. The main goal is to find the role of neurophysiological study (NFS) and Imaging-guided pudendal nerve infiltration (ImPNI) in PNE diagnosis and patient selection for surgery.

METHODS

A retrospective, multicentric study was conducted. Patients with PNE refractory to conservative treatment were included. Patient data, including NFS results, ImPNI, and surgical outcomes, were evaluated. A visual analogue scale was used to assess intervention response. Test performance metrics for NFS and ImPNI and binary logistic regression were used to determine their predictive value for postoperative improvement.

RESULTS

88 patients were diagnosed with PNE. All had NFS, and ImPNI was performed in 69 (78.4%), with 60 (68.2%) showing symptom improvement. Among the 40 patients (85%) who underwent pudendal nerve decompression surgery, 75% improved after surgery, and 20% did not. The combination of NFS and ImPNI showed a sensitivity of 79% and a specificity of 85.7%, with a Positive Predictive Value (PPV) of 98% and a Negative Predictive Value (NPV) of 30%. NFS and ImPNI were significant predictors of surgical success with p-values of 0.013 [ 95% CI: -23.6-19.9] and 0.003 [95% CI: -20.6 -18.5], respectively. Primary limitations: retrospective design and the absence of a control group.

CONCLUSIONS

NFS and ImPNI are essential and highly reliable tools for diagnosing PNE. ImPNI is a valuable predictor of surgical outcomes. These findings enable precise patient selection for surgery, ensuring optimal surgical outcomes.

Neural mobilisation effects in nerve function and nerve structure of patients with peripheral neuropathic pain: A systematic review with meta-analysis

OBJECTIVE

To assess the effects of neural mobilisation on nerve function and nerve structure of patients with peripheral neuropathic pain.

METHODS

A systematic review with meta-analysis was conducted. Medline, Embase, CINAHL, Cochrane Library, and World Health Organization International Clinical Trials Registry Platform were searched without restrictions. Eligibility criteria included controlled trials or quasi-experimental studies comparing neural mobilisation versus sham, active or inactive control in adults with peripheral neuropathic pain. Primary outcomes were the change in peripheral nerve cross-sectional area. Secondary outcomes included nerve echogenicity, nerve excursion and nerve conduction. Random effects meta-analysis was conducted. Risk of bias was assessed with the Cochrane Collaboration tool, and certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework.

RESULTS

Eleven randomised controlled trials and four quasi-experimental studies (total sample = 722 participants) were included. Thirteen studies included participants with carpal tunnel syndrome. Two studies examined the cross-sectional area, revealing improvements (i.e., a reduction) in the cross-sectional area after the neural mobilisation. Neural mobilisation improved motor [mean difference = 2.95 (95%CI 1.67 to 4.22)] and sensory conduction velocity in short-term [mean difference = 11.74 (95%CI 7.06 to 16.43)], compared to control. Neural mobilisation did not alter distal motor or sensory latency.

CONCLUSION

Neural mobilisation seems to improve (i.e., a reduced) the cross-sectional area (very low-quality evidence) and sensory conduction velocity (very low-quality evidence). Neural mobilisation was superior to control in improving motor conduction velocity in patients with peripheral neuropathic pain with moderate quality evidence. Distal motor or sensory latency presented similar results compared to other interventions. Our findings should be interpreted cautiously since most studies included patients with carpal tunnel syndrome.

Selective MR neurography-guided lumbosacral plexus perineural injections: techniques, targets, and territories

The T12 to S4 spinal nerves form the lumbosacral plexus in the retroperitoneum, providing sensory and motor innervation to the pelvis and lower extremities. The lumbosacral plexus has a wide range of anatomic variations and interchange of fibers between nerve anastomoses. Neuropathies of the lumbosacral plexus cause a broad spectrum of complex pelvic and lower extremity pain syndromes, which can be challenging to diagnose and treat successfully. In their workup, selective nerve blocks are employed to test the hypothesis that a lumbosacral plexus nerve contributes to a suspected pelvic and extremity pain syndrome, whereas therapeutic perineural injections aim to alleviate pain and paresthesia symptoms. While the sciatic and femoral nerves are large in caliber, the iliohypogastric and ilioinguinal, genitofemoral, lateral femoral cutaneous, anterior femoral cutaneous, posterior femoral cutaneous, obturator, and pudendal nerves are small, measuring a few millimeters in diameter and have a wide range of anatomic variants. Due to their minuteness, direct visualization of the smaller lumbosacral plexus branches can be difficult during selective nerve blocks, particularly in deeper pelvic locations or larger patients. In this setting, the high spatial and contrast resolution of interventional MR neurography guidance benefits nerve visualization and targeting, needle placement, and visualization of perineural injectant distribution, providing a highly accurate alternative to more commonly used ultrasonography, fluoroscopy, and computed tomography guidance for perineural injections. This article offers a practical guide for MR neurography-guided lumbosacral plexus perineural injections, including interventional setup, pulse sequence protocols, lumbosacral plexus MR neurography anatomy, anatomic variations, and injection targets.

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.

Estimate of the proportion of uncertain diagnoses of pudendal neuralgia in women with chronic pelvic-perineal pain: A systematic review with a descriptive data synthesis

BACKGROUND

There is a gap between pudendal neuralgia (PN) due to pudendal entrapment syndrome and PN without pudendal entrapment syndrome. The latter could have atypical symptoms.

AIM

Defining a rate of atypical PN from a clinical series of female patients with chronic pelvic-perineal pain.

METHODS

The atypical PN was defined as a pain not meeting clinical criteria for pudendal entrapment syndrome. The effect size was the rate of atypical PN. Such a rate was expected to be found among patients screened for enrollment in clinical series on pudendal neuropathic pain. A systematic search was performed looking for clinical series on PN. Studies must report information on female patients, pelvic-perineal pain, at least a clinical criterion for diagnosing the pudendal neurogenic origin of pain, the proportion of patients with pain not meeting the clinical criterion/a for diagnosing the pudendal entrapment pain.

RESULTS

From 2637 references, nine studies were included for qualitative analysis. Three of them were not suitable for data synthesis: one assessed the rate of PN after hip arthroscopy; second enrolled miscellaneous patients, a third investigated patients with gynecological diseases. Six studies involved patients with suspicion of pudendal entrapment symptoms (205 patients observed), allowing data synthesis. One of these series was judged as being of good quality. The overall rate of atypical PN is 0.013 (95% confidence interval, 0.008-0.021), I² 0%. Further analysis suggests the risk of bias for all studies.

CONCLUSIONS

Atypical PN in females is low when clinical criteria for pudendal entrapment syndrome are applied.

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.

Diagnostic Evaluation of Chronic Pelvic Pain

Chronic pelvic pain can result from various intra- and extra-pelvic etiologies. Although patient history and physical examination may narrow the differential diagnosis, frequently, the different etiologies have overlapping presentations. Imaging examinations such as US and/or MR imaging may help delineate the cause of pain, particularly when related to intra-pelvic organs, pelvic floor dysfunction or prolapse, synthetic material such as pelvic mesh or slings, and in some cases of neuropathic pain. Etiologies of neuropathic pain can also be assessed with non-imaging tests such as nerve conduction studies, electromyography, and testing of sacral reflexes.

Determinants of nerve conduction recovery after nerve injuries: Compression duration and nerve fiber types

INTRODUCTION

The aims of this study were to determine the influences of: (1) timing of nerve decompression; and (2) nerve fiber types on the patterns of nerve conduction studies (NCS) after nerve injury.

METHODS

Nerve conduction studies (NCS) were performed on 3 models of nerve injury: (1) crush injury due to transient nerve compression (crush group); (2) chronic constriction injury (CCI), or permanent compression (CCI group); and (3) CCI with removal of ligatures, or delayed nerve decompression (De-CCI group).

RESULTS

There were distinct patterns of NCS recovery. The crush and De-CCI groups achieved similar motor nerve recovery, better than that of the CCI group. In contrast, recovery of sensory nerves was limited in the CCI and De-CCI groups and was lower than in the crush group.

CONCLUSIONS

Immediate relief of compression resulted in the best recovery of motor and sensory nerve conduction. In contrast, delayed decompression restored only motor nerve conduction.

Lower urinary tract dysfunction in patients with peripheral nervous system lesions

The prevalence of lower urinary tract (LUT) dysfunction in peripheral nervous system (PNS) disorders is larger than in comparable control populations. This is particularly true for polyneuropathies with autonomic nervous system involvement, and for localized lesions with LUT innervation. LUT symptoms may be the guide to the diagnosis of processes localized in the lumbosacral spinal canal (as in cauda equina syndrome), and in the pelvis. Typical LUT dysfunctions (LUTD) caused by PNS involvement include bladder and sphincter hypoactivity with poor emptying, and incontinence. Paradoxically, bladder overactivity may also occur in pure PNS lesions. The acute cauda equina syndrome is an emergency requiring magnetic resonance imaging and surgery; in chronic neurogenic LUTD due to PNS involvement, the diagnosis of the lesion may be clarified by clinical neurophysiologic testing. Other important causes of neurogenic LUT dysfunction are perineoabdominal and pelvic surgeries. Surgeons are devising nerve-sparing techniques to prevent such major and often persistent complications in patients who are otherwise cured of the underlying disease. LUTD significantly affects the quality of life in patients and may lead to recurring urinary infections and upper urinary tract involvement. Thorough assessment of LUT function by urodynamics may be necessary in patients who are not improved by simple conservative measures.

Carpal and cubital tunnel and other, rarer nerve compression syndromes

BACKGROUND

Carpal tunnel syndrome is by far the most common peripheral nerve compression syndrome, affecting approximately one in every six adults to a greater or lesser extent. Splitting the flexor retinaculum to treat carpal tunnel syndrome is the second most common specialized surgical procedure in Germany. Cubital tunnel syndrome is rarer by a factor of 13, and the other compression syndromes are rarer still.

METHODS

This review is based on publications retrieved by a selective literature search of PubMed and the Cochrane Library, along with current guidelines and the authors' clinical and scientific experience.

RESULTS

Randomized controlled trials have shown, with a high level of evidence, that the surgical treatment of carpal tunnel syndrome yields very good results regardless of the particular technique used, as long as the diagnosis and the indication for surgery are well established by the electrophysiologic and radiological findings and the operation is properly performed. The success rates of open surgery, and the single-portal and dual-portal endoscopic methods are 91.6%, 93.4% and 92.5%, respectively. When performed by experienced hands, all these procedures have complication rates below 1%. The surgical treatment of cubital tunnel syndrome has a comparably low complication rate, but worse results overall. Neuro-ultrasonography and magnetic resonance imaging (neuro-MRI) are increasingly being used to complement the diagnostic findings of electrophysiologic studies.

CONCLUSION

Evidence-based diagnostic methods and treatment recommendations are now available for the two most common peripheral nerve compression syndromes. Further controlled trials are needed for most of the rarer syndromes, especially the controversial ones.

Sexual dysfunction in patients with peripheral nervous system lesions

Peripheral nervous system (PNS) disorders may cause sexual dysfunction (SD) in patients of both genders. These disorders include mainly polyneuropathies (particularly those affecting the autonomic nervous system (ANS)) and localized lesions affecting the innervation of genital organs. Impaired neural control may produce a malfunction of the genital response consisting of loss of genital sensitivity, erectile dysfunction, loss of vaginal lubrication, ejaculation disorder, and orgasmic disorder. In addition, there is often a loss of desire which actually has a complex pathogenesis, which goes beyond the mere loss of relevant nerve function. In patients who have no manifest health problems - particularly men with erectile dysfunction - one should always consider the possibility of an underlying polyneuropathy; in patients with SD after suspected denervation lesions of the innervation of genital organs within the lumbosacral spinal canal and in the pelvis, clinical neurophysiologic testing may clarify the PNS involvement. SD can alter self-esteem and lower patients' quality of life; opening up a discussion on sexual issues should be a part of the management of patients with PNS disorders. They may greatly benefit from counseling, education on coping strategies, and specific treatments.

Normative values of skin temperature and thermal sensory thresholds in the pudendal nerve territory

AIMS

The aim of this study was to define normative values of skin temperature and thermal sensory threshold in the pudendal nerve territory.

METHODS

Warm and cold detection thresholds (using the method of limits) and skin temperature were measured in a group of 41 presumably healthy female volunteers aged 41 years (range: 23-66 years) at left thenar eminence and in the pudendal nerve territory. Outlying data were discarded and 95% normative values were derived assuming Normal distributions.

RESULTS

Room temperature averaged 24.3 ± 1.1°. Skin temperature and cold detection threshold value were greater anteriorly (clitoris, labia) than posteriorly (para-anal). Para-anal skin temperature and cold detection threshold value were also significantly lower on the right side than on the left side. The warm detection threshold was significantly lower at the clitoris level than at left and right labia. A significant positive effect of skin temperature on cold and warm detection thresholds values was noted especially at thenar and para-anal levels. Age had no effect on skin temperature but warm detection thresholds at clitoris were higher in older subjects. The only qualitative abnormalities observed were after-sensation (4.9%) and habituation (2.8%). Allodynia, dysesthesia, radiation, and dyslocalization were not observed. Two-sided normative values were determined for skin temperature, vertical, and horizontal differences, while one-sided values were derived for cold and warm detection thresholds as well as for their difference.

CONCLUSIONS

Normative values for perineal skin temperature and thermal detection thresholds can be used as an alternative non-invasive way to evaluate pudendal neuropathy.

Magnetic resonance neurography-guided nerve blocks for the diagnosis and treatment of chronic pelvic pain syndrome

Magnetic resonance (MR) neurography - guided nerve blocks and injections describe a techniques for selective percutaneous drug delivery, in which limited MR neurography and interventional MR imaging are used jointly to map and target specific pelvic nerves or muscles, navigate needles to the target, visualize the injected drug and detect spread to confounding structures. The procedures described, specifically include nerve blocks of the obturator nerve, lateral femoral cutaneous nerve, pudendal nerve, posterior femoral cutaneous nerve, sciatic nerve, ganglion impar, sacral spinal nerve, and injection into the piriformis muscle.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

[General principles of the diagnostic approach to chronic postoperative pelvic and perineal pain]

INTRODUCTION

Chronic postoperative pain has been defined as pain arising after a surgical operation, present for at least 2 months, with no organic (active cancer or chronic infection) or pre-existing cause. The purpose of this article is to review the aetiological and diagnostic assessment of chronic postoperative pelvic and perineal pain.

MATERIAL AND METHODS

A review of the literature was performed by searching PUBMED for articles on the diagnostic approach to chronic postoperative pelvic and perineal pain.

RESULTS

The chronology of the symptoms, i.e., rapid onset of pain following a surgical procedure that does not subsequently resolve, is a leading argument to incriminate the surgical procedure in the pathogenesis of the pain. Clinical examination of the scars and detailed analysis of the topography and type of pain are essential elements in the analysis of this pain. The primary objective of complementary investigations (imaging, EMG, etc.) is to eliminate a differential diagnosis, as they are normal in the case of chronic postoperative pain. A test block of a nerve or trigger point is the main test performed to determine the level of the lesion responsible for pain.

CONCLUSION

The aetiological and diagnostic assessment of chronic postoperative pelvic and perineal pain requires a detailed clinical analysis based on examination of the scars and analysis of the clinical signs of muscle and nerve lesions. A local test block confirms the level of the lesion.

Misdiagnosed chronic pelvic pain: pudendal neuralgia responding to a novel use of palmitoylethanolamide

BACKGROUND

Pudendal neuralgia is a cause of chronic, disabling, and often intractable perineal pain presenting as burning, tearing, sharp shooting, foreign body sensation, and it is often associated with multiple, perplexing functional symptoms.

CASE REPORT

We report a case of a 40-year-old man presenting with chronic pelvic pain due to pudendal nerve entrapment and successfully treated with palmitoylethanolamide (PEA).

CONCLUSION

PEA may induce relief of neuropathic pain through an action upon receptors located on the nociceptive pathway as well as a more direct action on mast cells via an ALIA (autocoid local injury antagonism) mechanism. As recently demonstrated in animal models, the present case suggests that PEA could be a valuable pharmacological alternative to the most common drugs (anti-epileptics and antidepressants) used in the treatment of neuropathic pain.