Ganglion Impar Block

The ganglion impar is a mass of nerve cell bodies that is located near the tailbone (coccyx). This group of tailbone pain2nerves relays nociceptive signals (pain messages) from the genital and pelvic structures to the brain. A ganglion impar block is an injection that provides pain relief to patients who have disorders of the pelvis and perineum.

What conditions are treated with a ganglion impar block?

Conditions treated with the ganglion impar block include tailbone pain (coccydynia), chronic pelvic pain, abdominal and pelvic cancer pain, perineal hyperhidrosis (excessive sweating), failed back surgery syndrome, and postherpetic neuralgia in the sacral area.

The doctor often used this block as a diagnostic test to determine the source of perineal pain. Because this area contains diverse anatomic structures with mixed nerve sources, the pain is often difficult to pinpoint.

How does the ganglion impar block work?

The autonomic sympathetic nervous system transfers painful messages from the internal organs to the brain. The sympathetic chain involves two parallel nerves that run from the base of the skull to the coccyx on both sides of the vertebral column.

At the base of this chain, two sympathetic trunks merge to form the ganglion impar, which is located at the level of the sacrococcygeal joint. Numbing or ablating this nerve tissue halts the transmission of painful messages to the brain.

ganglion impar blockWhat is involved in the ganglion impar block procedure?

Before the procedure, the low back region is cleansed with an antiseptic, and the skin is numbed with a local anesthetic. The doctor will insert a fine needle into the lower back using x-ray guidance to assure correct placement. Once the needle is positioned into the ganglion impar, the doctor confirms position with contrast dye.

Once correct needle position has been established, the doctor can perform either a diagnostic block or a therapeutic block. The patient will have immediate pain relief with a successful ganglion impar block. For therapeutic purposes, the doctor may offer long-lasting pain relief by using radiofrequency ablation or neurolysis with alcohol or phenol to deaden the nerve mass.

What are the benefits of the ganglion impar block?

This procedure is a safe and effective therapy for neuropathic perineal pain. In a recent study that involved 8 patients, the researchers reported a 100% success rate with the ganglion impar block procedures, without any complications. At the end of a six-month period, the majority of patients experienced symptom relief without having to take pain medicine.

What are the risks associated with the ganglion impar block?

Although the ganglion impar block is a safe procedure, there are a few complications and risks. These include infection, bleeding, damage to the pelvic structures, and mild pain at the injection site. However, this procedure is a straightforward block, and when done by a skilled anesthesiologist, complications are Ganglion Impar Blockrare.

What results can I expect after the ganglion impar block?

The ganglion impar block is a safe, fast, and cost-effective pain intervention, and it can improve the quality of life for people who suffer from debilitating perineal and pelvic pain. The pain relief provided by the block varies from patient to patient, as well in duration and amount, but some people report relief that lasts for months to years.

In a recent case report, patients reported between 50 and 75% relief of pain after ganglion impar block injections. Because the procedure is considered low-risk, the block can be done multiple times.


Buttaci CJ, Foye PM, Stitik TP, et al. Coccydynia successfully treated with ganglion impar blocks: a case series. Am J Phys Med Rehabil. Mar 2005;84(3):218.

Oh CS, Chung IH, Ji HJ, et al. Clinical implications of topographic anatomy on the ganglion impar. Anesthesiology. Jul 2004;101(1):249-50.