What is a Ganglion Impar Block?

Ganglion impar block explained by Denver, Golden, Aurora, Boulder, Broomfield, Jefferson, and Littleton Colorado’s top pain doctors

Ganglion Impar BlockGanglion impar blocks are intended to inhibit pain associated with the tail bone (coccyx) of the body. This is felt in the region of the perineum and may be associated with nerve, organ, or tissue damage. It is often experienced as a vague or widely-distributed burning or discomfort in this area, which is controlled by the ganglion impar.

The ganglion impar is a cluster of nerve cells located in the front of the coccyx. It is also known as the sacroccygeal ganglion, or ganglion of Walther. It is part of the sympathetic portion of the autonomic nervous system that is responsible for the involuntary muscle functions of the body, such as bowel movements. Disorders of the sympathetic nervous system are linked with pain originating from blood vessels, nerves, and other tissues.

This ganglion also innervates part of the rectum and anus, perineum, parts of the urethra, a part of the vagina, and the vulva (in women) or scrotum (in men). Abnormal signaling in the nerves of the ganglion impar can result in chronic pain.

How is a Ganglion Impar Block Performed?

Preparation For ProcedureThe ganglion impar block was developed in 1990. Since then, the procedure has been refined to improve its effect and reduce discomfort in the patients treated. There are several variations on the ganglion impar block, based on the anatomy of the coccyx. These include the transsacrococcygeal approach, the transcoccygeal joint approach, the paracoccygeal corkscrew approach, and the paramedical approach. The transsacrococcygeal approach is the most widely used, due to its efficacy and ease of execution. An example of a study on this type of block evaluated its results in 16 consecutive patients. This study found that the duration of these procedures was just over 12 minutes on average, and all patients reported significant absence of pain as a result. Therefore, the transsacrococcygeal approach to the ganglion impar block was deemed effective and simple.

To carry out this technique, the patient is placed face down on an operating table, with a pillow supporting the pelvis to maintain the normal shape of the back. Sedatives are administered via IV. Vital signs are monitored at all times during the procedure. The skin above the coccyx is cleaned and a numbing agent is administered to it. Using real-time imaging (a fluoroscopic X-ray), the physician or pain specialist injects a mixture of local anesthetics and steroids into the ganglion impar. The procedure takes an average of fifteen minutes.

The ganglion impar block is associated with significant relief from visceral or nerve damage-related perineal pain. Some reports indicate that only one injection is required for total pain relief in the coccygeal area. Ganglion impar blocks are a minimally invasive and safe treatment for chronic pain that is otherwise quite difficult to address.

Ganglion impar injections are associated with rare incidences of complications, however. These include paralysis due to inaccurate or otherwise erroneous needle injection that can cause motor nerve damage. Other risks are infection, discomfort, and bleeding at the injection site. There are no reports of major complications arising as a result of a ganglion impar block.

Conditions Related To Ganglion Impar Block

Pain associated with the sympathetic nervous system has a complicated etiology. Chronic perineal pain has a wide variety of causative factors. Pain associated with the blood supply of this region is often linked to reasons such as reduced blood flow to nervous tissue. Visceral pain (pain associated with organs) may be associated with diseases such as upper abdominal cancer, rectal cancer, chronic pancreatitis, chronic perineal cancer, and non-malignant pelvic pain syndromes.

SacralOther conditions that may cause perineal pain include sacral postherpetic neuralgia, spinal cord malformations, and failed back surgery syndrome. In some cases, perineal pain may be related to an undiagnosed condition such as a sexually transmitted disease, urinary tract infection, or prostate inflammation. A consultation with a physician to analyze the possibility of one of these conditions is recommended before considering a ganglion impair block.


Ganglion impar blocks are a minimally invasive treatment for chronic perineal pain. This can be caused by a number of conditions and diseases of the region around the coccyx. The ganglion impar block, particularly the variant known as the transsacrococcygeal approach, is associated with significant pain relief and efficacy in these cases.

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