Pelvic Nerve Pain and Pudendal Neuralgia: Symptoms, Diagnosis and Treatment

The nerves of the pelvis

The pelvis is crossed by several nerves that can become pain generators. The pudendal nerve supplies the perineum, the clitoris and labia or penis, the urethra and the anal canal; it runs through a narrow channel between two ligaments where it is vulnerable to compression. The sacral plexus and sciatic nerve pass along the back wall of the pelvis toward the leg. The obturator nerve runs along the side wall to the inner thigh. The ilioinguinal, iliohypogastric and genitofemoral nerves supply the groin and upper thigh. The autonomic hypogastric plexus carries sensation from the pelvic organs. Any of these can be injured, entrapped or infiltrated.

Pudendal neuralgia: how it feels

• Burning, stabbing, electric or "foreign body" pain in the perineum, vulva, clitoris, penis, scrotum or rectum, on one or both sides.
• Worse with sitting, often within minutes, and eased by standing, lying down or sitting on a toilet seat, which takes pressure off the nerve.
• Typically does not wake you from sleep.
• May come with a sensation of a lump in the rectum or vagina, urinary urgency, pain after bowel movements or sexual arousal and orgasm pain.
• Numbness is usually absent; the problem is an irritated nerve, not a dead one.

The Nantes criteria

Because no test proves pudendal neuralgia, a group of French clinicians proposed the Nantes criteria in 2008, which remain the standard. All five essential criteria should be present: pain in the territory of the pudendal nerve; pain worsened by sitting; pain that does not wake the patient at night; no objective loss of sensation on examination; and relief of pain by a diagnostic pudendal nerve block. Supporting features include burning or electric quality, sensitivity to light touch, pain worsening through the day, and tenderness over the nerve on pelvic examination. Features that argue against it include pain only in the buttock or tailbone, pain only with bowel movements, and imaging abnormalities that explain the pain.

Causes

• Compression or entrapment of the pudendal nerve between the sacrospinous and sacrotuberous ligaments or in the pudendal canal, worsened by prolonged sitting and cycling.
• Stretch or injury during childbirth, pelvic surgery or pelvic fractures.
• Endometriosis infiltrating the pelvic nerves. Deep endometriosis can grow onto the sacral plexus, the sciatic nerve, the obturator nerve and the pudendal nerve, producing nerve pain that is at first cyclical and then constant. This is an under-recognized cause and an area where the surgeons behind PelviQuest focus their practice.
• Pelvic floor muscle spasm compressing the nerve from the surrounding muscles.
• Scar tissue after surgery for prolapse or incontinence.

How it is diagnosed

Diagnosis is clinical. A pelvic examination by someone trained in pelvic neuro-anatomy reproduces the pain by pressing along the course of the pudendal nerve and assesses the pelvic floor muscles. An image-guided pudendal nerve block that relieves the pain, even temporarily, is the confirmatory step. Pelvic MRI with neurography sequences can show nerve swelling or endometriosis along the nerve pathways, and is important when endometriosis is suspected, but a normal MRI does not exclude neuralgia. Nerve conduction studies are rarely decisive.

Treatment

• Remove the pressure: a cushion with a central cut-out for sitting, limiting cycling, and modifying work posture.
• Pelvic floor physical therapy to release the muscles around the nerve; often the most important first step.
• Neuropathic pain medication such as amitriptyline, gabapentin, pregabalin or duloxetine.
• Image-guided pudendal nerve blocks with local anesthetic and steroid, which are diagnostic and can be therapeutic.
• Pulsed radiofrequency or neuromodulation for persistent pain.
• Surgical decompression of the pudendal nerve for confirmed entrapment that has not responded to the above.
• When endometriosis is the cause, laparoscopic or robotic excision of the lesions from the nerves by a surgeon trained in pelvic neuropelveology addresses the source; medication alone rarely resolves nerve-infiltrating disease.

Pudendal neuralgia and endometriosis

Pudendal neuralgia and endometriosis meet in the same woman for three reasons. First, deep endometriosis can grow onto the pelvic nerves themselves. The published series mostly describe the sciatic nerve and the sacral plexus; one surgeon's review covered 267 women with sciatic nerve endometriosis confirmed at laparoscopy (Possover 2021). The pudendal nerve arises from the same sacral roots and runs through the same region, so it can be involved too, although this is reported less often. Second, years of pelvic pain cause the pelvic floor muscles to tighten, and tight muscles can compress the pudendal nerve where it passes between the sacrospinous and sacrotuberous ligaments. Third, pelvic surgery, including surgery for endometriosis, can injure the nerve or leave scar tissue around it.

Telling the two apart matters because the treatments differ. Pudendal neuralgia follows sitting, not the calendar. The Nantes criteria (Labat 2008) require pain in the territory of the pudendal nerve, worse with sitting, not waking the patient at night, no loss of sensation on examination, and relief with a pudendal nerve block. Endometriosis pain tracks the menstrual cycle, at least early on, and usually comes with painful periods, deep pain with sex or bowel symptoms. Hibner and colleagues (2010) note that the International Pudendal Neuropathy Association estimates pudendal neuralgia at about 1 in 100,000 people, that clinicians who treat it believe the true number is higher, and that it is often missed. When both are suspected, the workup combines a pelvic examination that maps nerve tenderness, imaging for deep endometriosis, and a diagnostic pudendal nerve block. Treatment then targets each driver separately: pelvic floor physical therapy, nerve-directed medication or blocks for the neuralgia, and excision of nerve-infiltrating endometriosis by a surgeon trained in pelvic nerve surgery.

Living with pelvic nerve pain while you wait for care

Keep a daily log of pain location and quality, what you were doing, how long you sat, and cycle day. A clear sitting pattern points to pudendal neuralgia; a clear cyclical pattern points to endometriosis; many women have both. Bring the log to a specialist in pelvic pain or a gynecologic surgeon with pelvic nerve expertise. Nerve pain is real, has a cause, and in most cases can be treated once it is named.