Your brain sends information to the body through pathways known as nerves. Nerves also receive information from the body and send it to the proper regions of the brain. A ganglion is a place in the body where many nerves intersect. Nerves that communicate some types of pain from the lower pelvis and groin pass through the ganglion impar on their way to the brain.
The ganglion impar sits just in front of your sacrum. The sacrum is the lowest part of the spine. It 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
- This is the area from the anus to the vagina or base of the testicles.
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.
A ganglion impar block might be needed if you have lower pelvic or groin pain caused by dysfunction or damage to organs in the area. Your healthcare provider may recommend it if you have tried other ways to control the pain. But your pain is still not manageable. For example, a ganglion impar block might help you if you have:
- Vaginal or vulvar cancer
- Scrotal cancer
- Rectal or anal cancer
- Bladder cancer
- Pain in the tailbone
- Rectal pain, or pain from other close structures
In some cases, your healthcare provider might use a ganglion impar block to diagnose the cause of your pain. Your doctor may inject a numbing medicine (local anesthetic) in the area to see if your pain lessens. Doing so may help pinpoint the source of pain. In other cases, your healthcare provider might use a ganglion impar block to treat your pain with other medicines.