What Is Ganglion Impar Block?

The ganglion Impar is the lowest most cluster of nerves bodies that is located just in front of the bottom of the tailbone behind the rectum. This is the boney area we commonly refer to as the coccyx below the sacrum. 

This ganglionic cluster of nerves is formed by a group of sympathetic nerves. Nerves leave the ganglion and they travel to blood vessels, and other structures near the tail bone, rectal area, and perianal area, the urethra and the vaginal area.


Nerve blocks of this ganglion are useful for painful conditions in the above mentioned areas including trauma, cancer, degenerative changes, fracture, and occasionally infections. 


Ganglion Impar Block Procedure

These procedures are done usually with x-ray guidance.

The patient is positioned facedown and x-ray images are taken of the coccyx from the top and from the side. A local anesthetic, numbing solution, is injected gently over the tailbone and a short blunt tip needle is gently advanced between the bones of the coccyx to travel just in front. This is where the ganglion sits.

The needle tip position is confirmed by injecting a small amount of contrast, x-ray Ink, which shows a dark  crescent appearance in front of the coccyx and behind the rectum.

Local anesthetic with or without steroids is injected in the area and the needle is removed and the area is cleaned and a bandage is applied.

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Before and After the Procedure and the Risks

After the procedure

The patient is discharged home the same day with instructions to keep the area clean and the bandage in place for at least 12 hours.

Ice can be applied for any local pain.

The effects from the local anesthetic can often be immediate, the steroid can provide relief a day later.

Relief of pain after this injection indicates that the ganglionic sympathetic nerves are responsible for the perceived pain.

This means that this injection is both diagnostic and therapeutic.

Your physician will want to see you after 1 to 2 weeks to determine if a second injection is necessary.


The risks from this procedure are surprisingly minimal.

As with all injections involving puncturing the skin, the risks of bleeding and infection are possible though less than 5%.