FAQ’s on Ganglion Impar Block for Chronic Pelvic and Coccyx Pain
What is a Ganglion Impar Block?
This is an outpatient injection performed for the management of chronic perineal pain. The injection is performed by pain management doctors and can provide instant, profound pain relief for a broad variety of pain conditions in the perineal area including the anus, coccyx, vulva, and the distal rectum/urethra/vagina.
What exactly is the Ganglion Impar?
The ganglion impar is located between one and three centimeters in front of the tip of the coccyx. There is significant variation in individuals as to the exact anatomic location, which probably explains why the nerve block may not work well in some patients.
The ganglion is a collection of nerve cells, and receives pain sensations from the perineum, distal rectum and urethra, anus, vulva, and distal third of the vagina. Because of the broad array of structures “connected” to the ganglion, a Ganglion Impar block may help substantially with pain reduction.
For what conditions is a Ganglion Impar block effective as a treatment?
The Ganglion Impar blcok works well for perineal pain originating from:
- Distal rectum and anus
- Distal urethra
- Vulva or distal third of vagina
- Cancer that has spread to perineum
- Sacral postherpetic neuralgia
- Other perineal pain conditions
There are quite a few variations of how a ganglion impar block is performed. The transsacrococcygeal approach remains the most popular method as it is extremely effective, yet simple to perform.
The patient lays face down with a pillow under the pelvic area. The area over the sacrum is numbed up, and with sterile technique a needle is passed in front of the coccyx area where the usual location of the ganglion impar is. After some dye confirms placement, numbing medicine is injected.
If the patient has had a previous diagnostic procedure with significant relief, then longer lasting pain relief may be obtained with injection of phenol or a radiofrequency ablation may be performed.
All in all, the procedure takes less than 15 minutes.
How well does a Ganglion Impar nerve block procedure work?
Multiple studies have proven the effectiveness of Ganglion Impar Blocks for perineal pain due to both malignant and non-malignant conditions. With malignancy in the perineal area, studies have shown ganglion impar blocks provide pain reduction ranging from 60% up to complete relief (Plancarte et al). Pain relief duration ranged from a few weeks to years.
In non-malignant conditions, most studies have shown ganglion impar blocks to
reduce perineal pain by 50% on average for a number of various conditions (vaginal protrusion, coccydynia, failed back surgery syndrome, postherpetic neuralgia, and more). As with malignancy, pain relief lasted from weeks to years (Agarwal-Kozlowski et al).
Interestingly, ganglion impar radiofrequency ablation has also been shown to produce excellent sustained perineal pain relief, similar to injection of phenol. If the initial block does not produce adequate pain relief, a different approach may be used since there may be significant variation in anatomic location of the ganglion impar between individuals.
What are the risks of a Ganglion Impar block?
The risks of a ganglion impar block are very low. There is a low risk of infection, nerve injury, or paralysis. There could also be some bleeding or an allergic reaction to the medication used. The main risk is inadequate pain relief.