What is the treatment for ganglion impar (Impar ganglion)?

From the Guidelines

The CPT code for ganglion impar block is 64999, which is an unlisted procedure code for the nervous system. This code is used because there is no specific CPT code assigned for ganglion impar blocks. When billing with code 64999, it's essential to include detailed documentation describing the procedure performed, including approach (transsacrococcygeal, paracoccygeal, or intercoccygeal), imaging guidance used (typically fluoroscopy), needle size, medication injected (usually a combination of local anesthetic and steroid), and medical necessity. The ganglion impar (also called ganglion of Walther) is a solitary retroperitoneal structure located at the level of the sacrococcygeal junction that provides sympathetic innervation to the perineum, distal rectum, anus, distal urethra, vulva, and distal third of the vagina. Blocks of this structure are performed to treat perineal pain, especially pain of sympathetic or cancer origin, as supported by the European Society for Medical Oncology (ESMO) clinical practice guidelines for the management of cancer pain in adult patients 1. Some key points to consider when performing a ganglion impar block include:

• The use of neurolytic blocks should be limited to patients with short life expectancy, as they usually produce a block lasting 3–6 months 1
• The block can be used as an adjuvant to decrease the use of oral and/or parenteral analgesics for visceral pain mechanisms 1
• Spinal neurolytic blocks can be helpful for localized pain and can be easily repeated if the effect is short-lasting 1
• The procedure should be performed under imaging guidance, typically fluoroscopy, to ensure accurate placement of the needle and medication. Some payers may require comparison to similar procedures (like other sympathetic blocks) when processing claims with this unlisted code, and reimbursement can vary significantly between insurance carriers.

From the Research

Ganglion Impar Block for Chronic Pelvic and Perineal Pain

• The ganglion impar block has been shown to be effective in managing chronic pelvic and perineal pain in various studies 2, 3, 4, 5, 6.
• A study published in 2014 found that neurolytic block of the ganglion impar was efficacious in patients with both malignancy-related and non-malignant chronic pelvic pain, with reported relief time varying from 4 weeks to 3 years 2.
• Another study published in 2017 found that repeated ganglion impar blocks allowed for short-term reduction of pain intensity with a moderate intermediate-term effect in patients with chronic pelvic and perineal pain 3.
• A 2025 study compared radiofrequency thermocoagulation of the ganglion impar with block using a combination of local anesthetic and steroid, and found that both techniques were effective in providing good pain relief, but radiofrequency thermocoagulation was better in terms of improvement in pain relief and patients' self-reported belief about the efficacy of treatment 4.
• The transsacrococcygeal approach to ganglion impar block has been found to be a technically feasible and safe technique, with significant pain relief during 2-month follow-up 5.
• A 2019 study found that the ganglion impar block was a safe and easy-to-perform technique, achieving satisfactory and statistically significant results in terms of pain control improvement and opioid consumption reduction in patients with pelvic and perineal oncological pain 6.

Techniques and Outcomes

• The ganglion impar block can be performed using various techniques, including neurolytic block, radiofrequency thermocoagulation, and block using a combination of local anesthetic and steroid 2, 3, 4, 5, 6.
• The outcomes of the ganglion impar block have been found to be significant in terms of pain relief, with reported relief time varying from 4 weeks to 3 years 2.
• The block has also been found to be effective in reducing opioid consumption in patients with chronic pelvic and perineal pain 6.

Safety and Efficacy

• The ganglion impar block has been found to be a safe technique, with no adverse events reported in several studies 2, 5, 6.
• The efficacy of the block has been found to be significant in terms of pain relief, with statistically significant reductions in pain scores reported in several studies 2, 3, 4, 5, 6.