FAQs on Ganglion Impar Block


Chronic pain in the genital and perineal area can be difficult to treat. Pain management specialists are using the ganglion impar block, which is a simple minimally-invasive technique for pain relief.

What is the ganglion impar?

The ganglion impar is a nerve bundle that lies at the end on the front of the coccyx (tailbone). There are four small sacral ganglia connected by ganglion cords, and below the two sympathetic structures lies the ganglion impar. Blockage of the ganglion impar can treat pain originating from the rectum, anus, perineum, distal urethra, vagina, vulva, scrotum, and coccyx.

What conditions are treated using the ganglion impar block?

The ganglion impar block is used to treat:

  • Perineal/rectal/anal malignancy pain
  • Vulvodynia
  • Vaginal protrusion pain
  • Endometriosis
  • Interstitial cystitis
  • Chronic prostatitis
  • Failed back surgery syndrome
  • Sympathetically-maintained pain due to complex regional pain syndrome
  • Postherpetic neuralgia
  • Radiation proctitis
  • Coccygodynia
  • Proctalgia fugax
  • Burning or localized perineal pain

What are the benefits of the ganglion impar block?

The ganglion impar block offers several benefits. These include:

  • It is a minimally-invasive procedure that is relatively easy to perform.
  • The injection only takes a few minutes and is done in the doctor’s office.
  • The procedure offers long-term pain relief (50-100% after the injection).
  • The block can treat multiple pelvic/perineal structures simultaneously.

How does the ganglion impar block work?

The sympathetic nervous system (SNS) is related to neuropathic (nerve-related) pain. The ganglion impar block has the ability to stop pain signal transmission from the nerve bundle to the spinal cord. Signals between the SNS and pain fibers are interrupted, which leads to dramatic pain relief. If the block works, the doctor may choose to perform radiofrequency ablation (RFA). This involves destruction of the affected nerves using radiofrequency energy.

How do I prepare for the ganglion impar block?

Before the procedure, you meet with the pain management specialist. The doctor will ask questions about your symptoms, take a medical history, and perform a physical examination. You should notify the doctor of what medications you take, as certain agents that thin the blood must be held for several days beforehand. When you decide to have the procedure, arrange to have someone drive you home, and wear loose-fitting clothing to your scheduled appointment. Because a sedative is given, do not eat or drink after midnight the night before your procedure.

How is the ganglion impar block done?

A diagnostic block is done to evaluate if or not the sympathetic nerves are the source of the pain. A therapeutic block is done to alleviate pain at the source. After the nurse places an IV in your arm, you are positioned face-down on the table. The skin is cleaned and numbed. Using x-ray guidance, the doctor injects an anesthetic, with or without a steroid agent, onto the ganglion impar nerve bundle. The needle is often inserted through the lower back using fluoroscopy to assure correct placement.

How many treatments will I need?

To assess if the ganglion impar is the source of pain, a diagnostic block is often done. Afterwards, the doctor may choose to use a neurolytic agent, anesthetic, or radiofrequency energy to block the pain signals. Pain relief after neurolysis lasts for several months.

What can I expect after the ganglion impar block procedure?

In several studies, researchers have proved that the ganglion impar block is useful for alleviating pain related to the ganglion impar nerves. In clinical trials, the efficacy rate of the ganglion impar block is 70-100%. In addition, researchers found that patients had up to four months of pain-free intervals following this block.


Agarwal-Kozlowski K, Lorke DE, Habermann CR, Am Esch JS, Beck H. CT-guided blocks and neuroablation of the ganglion impar (Walther) in perineal pain: anatomy, technique, safety, and efficacy. Clin J Pain. 2009; 25:570-6.

Reig E, Abejón D, del Pozo C, Insausti J, Contreras R. Thermocoagulation of the ganglion impar or ganglion of Walther: description of a modified approach. Preliminary results in chronic, nononcological pain. Pain Pract. 2005; 5:103-10.