Diagnostic & Therapeutic Procedure
Pudendal nerve block.
An image-guided pudendal nerve block is one of the most valuable tools in pelvic pain medicine — both to confirm the diagnosis of pudendal neuralgia and to provide meaningful therapeutic relief. Here is what to expect.
What a pudendal nerve block does
The pudendal nerve travels from the sacral plexus, wraps around the ischial spine, and enters the perineum through the Alcock canal. A block delivers local anaesthetic — often with a corticosteroid — precisely around this nerve, using CT, ultrasound or fluoroscopy for guidance.
The procedure has two roles: diagnostic (does pain temporarily disappear when this specific nerve is anaesthetised?) and therapeutic (does anti-inflammatory medication around the nerve reduce symptoms for weeks or months?).
How the procedure is performed
You lie prone. The skin over the buttock is cleaned and anaesthetised. Under live imaging, a fine needle is advanced to the ischial spine or into the Alcock canal. Contrast may be injected to confirm spread. Once positioning is confirmed, anaesthetic — with or without steroid — is delivered.
The whole procedure typically takes 20–30 minutes. Most patients walk out and can resume light activity the same day.
How long relief lasts
Anaesthetic effect begins within minutes and typically lasts 2 to 8 hours. This early window is diagnostically important — patients are asked to keep a symptom diary.
If corticosteroid is included, additional relief usually begins 3–7 days later and can last weeks to several months. In some patients, repeated blocks combined with pelvic floor rehabilitation are sufficient to resolve symptoms.
What the response tells us about surgery
A clearly positive block — especially reproducible across two blocks — is one of the strongest predictors of a good response to pudendal nerve decompression surgery. It confirms that pain is indeed generated by the pudendal nerve and localises the responsible side.
Conversely, if a technically successful block produces no relief, the pain source is likely elsewhere: pelvic floor dysfunction, sacral or lumbar nerve pathology, or central sensitisation. This changes the treatment plan and often avoids unnecessary surgery.
Common questions
What is a pudendal nerve block?
A pudendal nerve block is an injection of local anaesthetic — sometimes combined with a corticosteroid — placed directly around the pudendal nerve under CT, ultrasound or fluoroscopic guidance. It is used both to confirm the diagnosis of pudendal neuralgia and to provide therapeutic relief.
How long does a pudendal nerve block last?
Diagnostic anaesthetic-only blocks typically last a few hours to a few days. Therapeutic blocks with corticosteroid may provide relief for weeks to several months, depending on the underlying pathology and individual response.
Does a pudendal nerve block hurt?
The injection is performed under local anaesthesia and is generally well tolerated. Patients feel pressure and a brief sting when the local anaesthetic is placed. Deeper needle passage can produce a transient shooting sensation as the nerve is approached — this actually helps confirm correct positioning.
How do I prepare for a pudendal nerve block?
Preparation typically includes stopping blood-thinning medication (with your prescriber's approval), arranging transport home, wearing loose clothing, and eating lightly beforehand. Your team will provide specific instructions based on the imaging guidance used.
What does a positive pudendal nerve block mean?
Significant temporary pain relief following an image-guided block strongly supports the diagnosis of pudendal neuralgia. It also predicts which patients are most likely to benefit from further intervention, including pudendal nerve decompression surgery.
How many pudendal nerve blocks can I have?
Most protocols allow up to three corticosteroid blocks per year to avoid tissue side effects. Diagnostic anaesthetic-only blocks can be repeated more often if needed to confirm anatomy or laterality.
Are pudendal nerve blocks dangerous?
Serious complications are rare when the block is performed under image guidance by an experienced clinician. Possible risks include bleeding, infection, transient worsening of pain, and temporary weakness of pelvic floor muscles on the injected side.
Speak with a pudendal nerve specialist.
Dr Renaud Bollens leads a specialist practice dedicated to chronic pelvic pain, with centers in Dubai and Belgium.