Pudendal neuralgia caused by pudendal nerve entrapment (PNE) is a chronic and severely disabling neuropathic pain syndrome. It presents in the pudendal nerve region and affects both males and females. It is mostly underdiagnosed and inappropriately treated and causes significant impairment of quality of life.
Anatomy of the Pudendal Nerve:
The pudendal nerve emerges from the S2, S3, and S4 roots' ventral rami of the sacral plexus. It carries sensory, motor, and autonomic fibers; however, an injury to the pudendal nerve causes sensory deficits more than motor. It courses between two muscles, the piriformis and coccygeus muscles. It departs the pelvic cavity through the greater sciatic foramen ventral to the sacrotuberous ligament. It passes medial to and under the sacrospinous ligament at the ischial spine level to re-enter the pelvic cavity through a lesser sciatic foramen. The pudendal nerve then courses in the pudendal canal, which is also called the Alcock canal. The three last branches of the pudendal nerve terminate in the ischioanal fossa. These are the inferior rectal branch, perineal branch, and dorsal sensory nerve of the penis or clitoris. However, there are case reports which have shown variability in the anatomy of the pudendal nerve.
The pudendal nerve entrapment syndromes subdivide into four types based on the level of compression.
Pudendal neuralgia can arise from mechanical or non-mechanical injury. The mechanical injury can be due to compression, transaction, or stretching. Amongst the mechanical causes, compression caused by PNE is the most common cause. The non-mechanical causes of pudendal neuropathy include viral infections (herpes zoster, HIV), multiple sclerosis, diabetes mellitus, and others.
The first reported case of pudendal neuralgia was due to cycling, which results due to continuous pressure on the Alcock canal.
The causes of pudendal neuralgia are:
PNE is a rare syndrome, and the prevalence is unknown. As estimated by the International Pudendal Neuropathy Foundation, the incidence of this condition is 1 per 100,000, but the actual incidence might be higher than reported.
The presenting features of PNE are discussed below
The physical examination in patients with PNE is relatively normal, except for pain reproduction. The symptoms depend on the site of entrapment. If the nerve gets entrapped at the ischial spine or the sacrospinous ligament, it causes pain medial to the ischium. Similarly, tenderness over the greater sciatic notch results when the nerve gets entrapped at, the greater sciatic notch. Entrapment at the piriformis leads to spasm and tenderness of piriformis muscle. Lastly, entrapment at the Alcock canal and obturator internus result in tenderness and spasm of the obturator internus muscle.
In some cases, a transrectal or transvaginal examination might be included in the patient examination to exclude intrapelvic entrapment.
Pudendal nerve entrapment is a potentially challenging condition to diagnose because there are no specific diagnostic tests. The clinician needs to realize that it is exceedingly mandatory to get a thorough history and perform a detailed physical examination to reach a diagnosis. Dr. Roger Robert published the Nantes criteria to diagnose PNE and appears in detail below. This criterion has validation by many European physicians who have ample experience treating similar conditions.
Complementary diagnostic criteria:
The following tests can help in the diagnosis:
There are no specific and consistent radiological findings in patients with PNE, and further research is necessary.
If the patient fulfills the Nantes criteria, no further investigation is needed to make the diagnosis. However, if the patient lacks any of the criteria, further evaluation should be pursued. MRI helps to rule out other causes of chronic pain in such cases.
The treatment options are as below:
Since there is no confirmatory diagnostic test, pudendal neuralgia is a diagnosis of exclusion. Other conditions merit consideration before making a final diagnosis.
Pudendal neuralgia due to PNE affects the quality of life immensely. However, it does not affect life expectancy.
The complications associated with pudendal nerve block are:
Patients should be educated to avoid painful stimuli and actively participate in physiotherapy. Lifestyle modifications are one of the essential elements of the treatment plan.
It is crucial to understand that all types of pudendal neuralgias are not the result of PNE in the treatment planning of patients with chronic pain. It is essential to realize that the pudendal nerve can get trapped at different locations, and therefore, all patients will not benefit from the same therapy. Patients with chronic pain syndromes tend to get frustrated with multiple failed treatments and can be clinically depressed as well.
A study was conducted by Raynor et al. on 1024 patients to study the prevalence of depression in patients with chronic pain and its impact on health care cost. They categorized 60.8% of patients with chronic pain into probable depression and 33.8% into severe depression based on a questionnaire survey. They also reported higher health care cost amongst patients with depression (p=0.001). Similar results can be seen in data analysis by the medical expenditure panel survey of 26671 patients from 2008 to 2011. The research found that different levels of pain interference increase the total health care cost.
Chronic pain poses a mental and economic burden on the patient. These aspects should be considered when providing care to patients.
Pudendal neuralgia due to PNE is a rare neuropathic condition. It causes a significant impairment of quality of life. It often does not get diagnosed promptly, and most patients get treated for other conditions. Thus Nantes diagnostic criteria were established and validated by an interprofessional team to aid in the diagnosis and further treatment of such patients. If the patient fulfills the Nantes criteria, no further investigation is required. However, if any of the criteria are not present, the patient should be further evaluated, and MRI is generally done to rule out other causes of chronic pain. Individualized treatment is necessary. It typically requires permanent lifestyle changes and physical therapy. The treatment options include pharmacological therapy, CT guided blocks, decompression surgery, and neuromodulation.
A well-coordinated interprofessional healthcare team comprised of a pain physician, surgeon, anesthesiologist, nurse, radiologist, and physiotherapist to help in physical rehabilitation is necessary to treat this challenging neuropathic syndrome. All these disciplines need to collaborate across interprofessional boundaries to optimize care and outcomes. [Level 5]
|||Ploteau S,Labat JJ,Riant T,Levesque A,Robert R,Nizard J, New concepts on functional chronic pelvic and perineal pain: pathophysiology and multidisciplinary management. Discovery medicine. 2015 Mar; [PubMed PMID: 25828522]|
|||Maldonado PA,Chin K,Garcia AA,Corton MM, Anatomic variations of pudendal nerve within pelvis and pudendal canal: clinical applications. American journal of obstetrics and gynecology. 2015 Nov; [PubMed PMID: 26070708]|
|||Montoya TI,Calver L,Carrick KS,Prats J,Corton MM, Anatomic relationships of the pudendal nerve branches. American journal of obstetrics and gynecology. 2011 Nov; [PubMed PMID: 21889763]|
|||Filler AG, Diagnosis and treatment of pudendal nerve entrapment syndrome subtypes: imaging, injections, and minimal access surgery. Neurosurgical focus. 2009 Feb; [PubMed PMID: 19323602]|
|||Robert R,Prat-Pradal D,Labat JJ,Bensignor M,Raoul S,Rebai R,Leborgne J, Anatomic basis of chronic perineal pain: role of the pudendal nerve. Surgical and radiologic anatomy : SRA. 1998; [PubMed PMID: 9658526]|
|||Ramsden CE,McDaniel MC,Harmon RL,Renney KM,Faure A, Pudendal nerve entrapment as source of intractable perineal pain. American journal of physical medicine [PubMed PMID: 12820792]|
|||Leibovitch I,Mor Y, The vicious cycling: bicycling related urogenital disorders. European urology. 2005 Mar; [PubMed PMID: 15716187]|
|||Marcus-Braun N,Bourret A,von Theobald P, Persistent pelvic pain following transvaginal mesh surgery: a cause for mesh removal. European journal of obstetrics, gynecology, and reproductive biology. 2012 Jun; [PubMed PMID: 22464208]|
|||Sancak EB,Avci E,Erdogru T, Pudendal neuralgia after pelvic surgery using mesh: Case reports and laparoscopic pudendal nerve decompression. International journal of urology : official journal of the Japanese Urological Association. 2016 Sep; [PubMed PMID: 27250921]|
|||Heinze K,Nehiba M,van Ophoven A, [Neuralgia of the pudendal nerve following violent trauma: analgesia by pudendal neuromodulation]. Der Urologe. Ausg. A. 2012 Aug; [PubMed PMID: 22751935]|
|||Lien KC,Morgan DM,Delancey JO,Ashton-Miller JA, Pudendal nerve stretch during vaginal birth: a 3D computer simulation. American journal of obstetrics and gynecology. 2005 May; [PubMed PMID: 15902175]|
|||Sultan AH,Kamm MA,Hudson CN, Pudendal nerve damage during labour: prospective study before and after childbirth. British journal of obstetrics and gynaecology. 1994 Jan; [PubMed PMID: 8297863]|
|||Hibner M,Desai N,Robertson LJ,Nour M, Pudendal neuralgia. Journal of minimally invasive gynecology. 2010 Mar-Apr; [PubMed PMID: 20071246]|
|||Waldinger MD,Venema PL,van Gils AP,Schweitzer DH, New insights into restless genital syndrome: static mechanical hyperesthesia and neuropathy of the nervus dorsalis clitoridis. The journal of sexual medicine. 2009 Oct; [PubMed PMID: 19732313]|
|||Shafik A,El Sibai O,Shafik IA,Shafik AA, Role of sacral ligament clamp in the pudendal neuropathy (pudendal canal syndrome): results of clamp release. International surgery. 2007 Jan-Feb; [PubMed PMID: 17390916]|
|||Martin R,Martin HD,Kivlan BR, NERVE ENTRAPMENT IN THE HIP REGION: CURRENT CONCEPTS REVIEW. International journal of sports physical therapy. 2017 Dec; [PubMed PMID: 29234567]|
|||Labat JJ,Riant T,Robert R,Amarenco G,Lefaucheur JP,Rigaud J, Diagnostic criteria for pudendal neuralgia by pudendal nerve entrapment (Nantes criteria). Neurourology and urodynamics. 2008; [PubMed PMID: 17828787]|
|||Choi SS,Lee PB,Kim YC,Kim HJ,Lee SC, C-arm-guided pudendal nerve block: a new technique. International journal of clinical practice. 2006 May; [PubMed PMID: 16700853]|
|||Walk D,Sehgal N,Moeller-Bertram T,Edwards RR,Wasan A,Wallace M,Irving G,Argoff C,Backonja MM, Quantitative sensory testing and mapping: a review of nonautomated quantitative methods for examination of the patient with neuropathic pain. The Clinical journal of pain. 2009 Sep; [PubMed PMID: 19692806]|
|||Mollo M,Bautrant E,Rossi-Seignert AK,Collet S,Boyer R,Thiers-Bautrant D, Evaluation of diagnostic accuracy of Colour Duplex Scanning, compared to electroneuromyography, diagnostic score and surgical outcomes, in Pudendal Neuralgia by entrapment: a prospective study on 96 patients. Pain. 2009 Mar; [PubMed PMID: 19195783]|
|||Wadhwa V,Hamid AS,Kumar Y,Scott KM,Chhabra A, Pudendal nerve and branch neuropathy: magnetic resonance neurography evaluation. Acta radiologica (Stockholm, Sweden : 1987). 2017 Jun [PubMed PMID: 27664277]|
|||Filler AG,Haynes J,Jordan SE,Prager J,Villablanca JP,Farahani K,McBride DQ,Tsuruda JS,Morisoli B,Batzdorf U,Johnson JP, Sciatica of nondisc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment. Journal of neurosurgery. Spine. 2005 Feb; [PubMed PMID: 15739520]|
|||Fanucci E,Manenti G,Ursone A,Fusco N,Mylonakou I,D'Urso S,Simonetti G, Role of interventional radiology in pudendal neuralgia: a description of techniques and review of the literature. La Radiologia medica. 2009 Apr; [PubMed PMID: 19277838]|
|||Erdogru T,Avci E,Akand M, Laparoscopic pudendal nerve decompression and transposition combined with omental flap protection of the nerve (Istanbul technique): technical description and feasibility analysis. Surgical endoscopy. 2014 Mar; [PubMed PMID: 24149853]|
|||Valovska A,Peccora CD,Philip CN,Kaye AD,Urman RD, Sacral neuromodulation as a treatment for pudendal neuralgia. Pain physician. 2014 Sep-Oct; [PubMed PMID: 25247915]|
|||Buffenoir K,Rioult B,Hamel O,Labat JJ,Riant T,Robert R, Spinal cord stimulation of the conus medullaris for refractory pudendal neuralgia: a prospective study of 27 consecutive cases. Neurourology and urodynamics. 2015 Feb; [PubMed PMID: 24249588]|
|||Frank CE,Flaxman T,Goddard Y,Chen I,Zhu C,Singh SS, The Use of Pulsed Radiofrequency for the Treatment of Pudendal Neuralgia: A Case Series. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC. 2019 Mar 22; [PubMed PMID: 30910339]|
|||Venturi M,Boccasanta P,Lombardi B,Brambilla M,Contessini Avesani E,Vergani C, Pudendal Neuralgia: A New Option for Treatment? Preliminary Results on Feasibility and Efficacy. Pain medicine (Malden, Mass.). 2015 Aug [PubMed PMID: 25677417]|
|||Leone JE,Middleton S, Nontraumatic Testicular Pain due to Sacroiliac-Joint Dysfunction: A Case Report. Journal of athletic training. 2016 Aug; [PubMed PMID: 27626835]|
|||Kurzel RB,Au AH,Rooholamini SA, Retroperitoneal hematoma as a complication of pudendal block. Diagnosis made by computed tomography. The Western journal of medicine. 1996 Jun; [PubMed PMID: 8764634]|
|||Sheng J,Liu S,Wang Y,Cui R,Zhang X, The Link between Depression and Chronic Pain: Neural Mechanisms in the Brain. Neural plasticity. 2017 [PubMed PMID: 28706741]|
|||Rayner L,Hotopf M,Petkova H,Matcham F,Simpson A,McCracken LM, Depression in patients with chronic pain attending a specialised pain treatment centre: prevalence and impact on health care costs. Pain. 2016 Jul [PubMed PMID: 26963849]|
|||Stockbridge EL,Suzuki S,Pagán JA, Chronic pain and health care spending: an analysis of longitudinal data from the Medical Expenditure Panel Survey. Health services research. 2015 Jun [PubMed PMID: 25424348]|