FAQs on Ganglion Impar Block

The ganglion impar block involves injecting medication onto the group of nerves behind the coccyx (tailbone). The ganglion impar is a nerve bundle that supplies the lower back region.

What is the reason for the ganglion impar block?

The ganglion impar block is used to decrease pain in the distal rectum, vulva, lower urethra, and perineum. This block is used to alleviate cancer pain associated with these structures.

What medications are used in the ganglion impar block procedure?

The doctor can inject a local anesthetic (bupivicaine or lidocaine) along with a corticosteroid agent (triamcinolone or methylprednisolone). The doctor may choose to inject a neurolytic agent, such as phenol or absolute alcohol.

How can I prepare for the ganglion impar block?

To prepare for the procedure, you need to notify the doctor of all your medications. Certain blood-thinning agents must be held beforehand. In addition, you cannot have the procedure if you have an active infection, a bleeding disorder, or an uncontrolled heart condition. If you are a diabetic, your glucose should be well-controlled before the procedure. When you arrive at the medical center, a nurse goes over the risks and benefits and has you sign a consent form. An IV line is placed in your hand/arm, and the nurse attaches monitoring devices to your body, which assess heart rate, blood pressure, and oxygen level.

How is the ganglion impar block performed?

After positioning you face-down, the doctor cleans the skin with an antiseptic. The skin and deeper tissues are numbed using a local anesthetic agent. Once numb, the doctor uses x-ray guidance to insert a needle near the affected nerves. After injecting necessary medications, the needle is then removed, and a small bandage is applied. Total procedure time is around 30 minutes.

What happens after the ganglion impar block procedure?

Immediately after the procedure, a nurse monitors you for around 30 minutes. Expect to have some heaviness, weakness, and numbness of the lower extremities. We advise you to rest the remainder of the day, and gradually return to usual activities. The injection site is usually sore for 2-3 days, so use an ice pack for 20-minute intervals several times each day.

How many blocks will I need?

The majority of patients report relief after one injection procedure. However, the duration of pain relief is not the same for everybody. The pain specialist may recommend 1-2 repeat injections if you have good results after the initial injection.

What conditions are treated using the ganglion impar block?

Any condition involving sympathetic nerve pain will respond to the ganglion impar block. Conditions treated include:

  • Chronic perineal pain
  • Non-malignant pelvic pain syndromes
  • Upper abdominal pain
  • Chronic pancreatitis
  • Failed back surgery syndrome
  • Spinal arthritis with radiculopathy
  • Poor blood supply to the nerves
  • Sacral post-herpetic neuralgia

What risks and side effects are associated with the ganglion impar block?

The ganglion impar block is effective and safe. However, as with other minimally invasive procedures, there are a few risks to consider. These include bleeding, nerve damage, infection, puncture of an organ, and blood vessel damage. Side effects to medications include dizziness, dry mouth, weakness, drowsiness, numbness of the lower extremities, and diarrhea.

What is the success rate of the ganglion impar block?

In recent clinical studies, the efficacy rate for this procedure is between 70% to 90%. Many patients report complete symptoms relief. The technical success rate is 100%, according to research reports.


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

Lin CS, Cheng JK, Hsu YW, Chen CC, Lao HC, et al. Ultrasound-guided ganglion impar block: A technical report. Pain Medicine. 2010;11:390-394.

Menon R, Swanepoel A. Sympathetic blocks. Contin Educ Anaesth Crit Care Pain. 2010;10(2):88-92.