Pudendal neuralgia (PN) is a chronic neuropathic pain, aggravated by sitting and for which no organic cause can be found by imaging studies. It is often associated with pelvic dysfunction.
The estimated prevalence in France is 1/6000.
The disease usually presents between the ages of 50-70 years, with an insidious onset of symptoms. PN manifests with neuropathic pain of varying intensity in the perineal region. The pain is described as an intense, sharp, burning sensation, and sometimes as numbness. Rectal or vaginal foreign body sensation (sympathalgia) has also been reported. Pain is unilateral or often medial, and is more intense during the day, when sitting or when wearing tight clothing. The pain is often associated with pelvic sensitization, which explains the urinary (pollakiuria, dysuria), anorectal (dyschezia, increased pain after bowl movement) and sexual (dyspareunia, intolerance of vulval contact, post-coital exacerbation of pain, persistent genital arousal, erectile dysfunction) problems as well as myofascial pain in the buttocks. The co-occurrence of truncal sciatica is common. Several forms of PN exist: benign, regressive, evolutive with flares, stable, and very debilitating forms with progressive symptom aggravation.
The cause of PN is unclear. The pudendal nerve can be compressed or entrapped. Numerous potential nerve compression zones exist: pinching by posterior pelvis ligaments (comprised of the sacrotuberous and sacrospinalis ligaments), in the Alcock's canal (due to splitting of the obturator muscle aponeurosis) and the falciform process of the sacrotuberous ligament. There is also the possibility of proximal entrapment at the level of the sub-piriformis canal and distal entrapment of the dorsal nerve of the clitoris/penis at the level of the sub-pubic canal. PN can also be caused by excessive bicycling, childbirth, and scarring after surgery or radiation.
The diagnostic criteria for PN includes the presence of pain in the distribution of the pudendal nerve that is worsened by sitting, with no objective sensory impairment, which does not provoke awakening in the night, and that is relieved with anesthesia by pudendal nerve block. MRI allows for PN to be classified, based on the entrapment site: type I, in the sciatic notch; type II, the ischial spine and sacrosciatic ligament; type IIIa, the obturator internus muscle; type IIIb, the obturator internus and piriformis muscles, and type IV, the distal branches of the pudendal nerve. Normal imaging findings do not exclude a diagnosis of PN.
Differential diagnosis includes compression by nerve tumors (neurofibroma (see this term), schwannoma), extrinsic compression (endometriosis, bone metastasis), infections or local dermatological involvement (chronic urethritis, lichen sclerosus (see this term)), other sacral neuropathies (post-shingles, post-herpetic), transient proctalgia, perineal neuropathy due to stretching during childbirth, complex regional pain syndromes, perineal neuropathy involving the inferior clunial nerve, ischiatic bursitis, piriformis syndrome, and provoked vulvodynias.
Management includes the treatment of neuropathic pain (with gabapentin, pregabalin, duloxetine, amitriptyline), percutaneous posterior tibial nerve stimulation, physiotherapy, osteopathy and short-term psychotherapy. The effect of anesthetic infiltration of the pudendal nerve is limited. In refractory forms, transgluteal decompression of the pudendal nerve has been effective. In those where surgery has been ineffective, an implantable neurostimulator at the level of the terminal cone can be proposed.
PN greatly affects quality of life, but has no effect on life expectancy.
Last update: April 2014