Ganglion Impar Block

The Ganglion Impar is part of the sympathetic nervous system. It is a bundle of nerve cells in front of the tailbone (sacral/coccyx) joint.

These nerve cells can cause chronic tailbone (coccyx/sacral), pelvic pain, genital (perineal) pain, and rectal pain.

The ganglion impar sits just in front of your sacrum. The sacrum is just above the tailbone (coccyx). Nerves from some parts of the lower pelvis and groin pass through this ganglion, including nerves from:

Lower part of the rectum
Anal region
Lower part of the urethra
Vagina and vulva
Perineum
Scrotum
Tailbone

A ganglion impar block involves the injection of a local anesthetic (lidocaine or bupivacaine) around the ganglion impar. ultrasound guidance or X-ray is to ensure proper placement.

This procedure is intended to temporarily block these sympathetic nerves with local anesthetics. Sometimes patients prefer sedation as the injection can be painful. Blocking these nerves can resets the nerves back intovtheir normal state, thus treating the pain syndrome, but is not always successful for pudendal neuralgia.

A ganglion is a collection or bundle of neuronal bodies (where they intersect) found in the voluntary and autonomic branches of the peripheral nervous system (PNS). Ganglia can be thought of as synaptic relay stations between neurons Information enters the ganglia, excites the neuron in the ganglia and then exits.

Lower part of the rectum
Anal region
Lower part of the urethra
Vagina and vulva
Perineum
Scrotum
Tailbone

During a ganglion impar block, your healthcare provider will put a needle into the area near your tailbone between your buttocks. He or she will then move it to a position just in front of the sacrum. That’s where the ganglion impar is. Medicine to help block pain signals in the area will then be injected.

What are the risks of a ganglion impar block?

Ganglion impar block is generally very safe. Some rare risks of the procedure are:

Damaging structures (organs) adjacent to the ganglion impar
Bleeding
Infection
Allergic reaction to the medicine or medicines

The Procedure:

Most patients receive sedation for this procedure. The block itself is performed while the patient is in a prone position (on stomach) but the medical team may move you into position after you are asleep.
The medical team will clean the area and drape your body.
The procedure should only take 15 minutes.
The area where you will have the shot will be cleaned.
The provider will insert a needle into the area around your tailbone between your buttocks. He or she will advance the needle until it is in the area of the ganglion impar. He or she may use ultrasound to help guide the needle. The provider will inject a small amount of X-ray contrast dye through the needle to make sure it is in exactly the right spot.
The provider will then inject their anesthetic medication (Lidocaine or Buvidicaine) through the needle. He or she might use different types of medicine for different reasons. Numbing medicine may be needed to block pain.

Generally, staff observes the patent 30 to 60 minutes after the procedure. Make sure someone can drive you home. You should not plan to do anything strenuous or anything that calls for your full attention for the rest of the day.

Our anecdotal evidence is that pain at the injection site can last much longer, weeks to months. People seem to notice it most when sitting up straight driving or at work. It varies individual to individual.

Our anecdotal evidence hasn't shown this procedure helps with pudendal neuralgia.

EFFECACY

Ganglion Impar

The ganglion impar is a solitary retroperitoneal structure located at the level of the sacrococcygeal junction that marks the termination of the paired paravertebral sympathetic chains.

Although published experience is limited and criteria for predicting success or failure are not available, patients with poorly localized perineal pain with a burning character are considered candidates for a ganglion impar block.

This means that patients with localized perineal pain are not good candidates.

Pelvic Pain

Sunil J. Panchal M.D..

Ganglion Impar Block

The ganglion impar is the termination of the paired paravertebral sympathetic chains. This terminal end is a single ganglion located anterior to the sacrococcygeal junction. Blockade of this structure has been introduced within the last decade to manage intractable perineal cancer pain involving the sympathetic nervous system.

Sympathetically mediated perineal pain usually is poorly localized and has components of burning and urgency. Ganglion impar block and neurolysis has been reported to achieve 70% to 100% pain relief for perineal pain caused by cancer of the cervix, colon, bladder, rectum, or endometrium.

PELVIC PAIN

Paul J. Christo, Greg Hobelmann, in Current Therapy in Pain, 2009

PELVIC PAIN - Ganglion Impar Block

Complications

Sacral nerve root injury (neurolysis), rectal perforation, periosteal injection, and epidural spread may occur.

Factors associated with Successful Responses to Ganglion Impar Block: A Retrospective Study

Int J Med Sci. 2021; 18(13): 2957–2963.

Published online 2021 Jun 11. doi: 10.7150/ijms.60962 PMCID: PMC8241784 PMID: 34220323

Background: The ganglion impar (ganglion of Walther) block has been used to manage coccygeal and perineal (perianal and genital) pain due to both benign and malignant causes. However, the factors associated with successful responses to ganglion impar block are unknown. Therefore, in the present study, we aimed to identify the independent factors associated with successful responses to ganglion impar block in patients with chronic pain in coccygeal and perineal regions..

In conclusion, ganglion impar block may be more effective in cancer-related pain than pain due to benign causes. Therefore, ganglion impar block could be a treatment option for pain due to pelvic or perineal organ cancer. 1

Pudendal neuralgia is a benign cause.

1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8241784/