Would a ganglion impar (ganglion of impar) block alleviate chronic bladder and pelvic pain?

From the Guidelines

A ganglion impar block may be considered for alleviating chronic bladder and pelvic pain, particularly in patients who have failed conservative treatments and have a neuropathic component to their pain, as it can interrupt sympathetic nerve signals contributing to pain perception in the pelvic region. When considering this procedure, it is essential to note that the American Urological Association (AUA) guideline for the diagnosis and treatment of interstitial cystitis/bladder pain syndrome emphasizes a multi-modal approach, combining pharmacologic agents with other therapies, and prioritizes treating underlying bladder-related symptoms 1. The ganglion impar block involves injecting local anesthetic, with or without steroids, at the ganglion impar, located anterior to the sacrococcygeal junction, and patients typically undergo diagnostic blocks first to assess effectiveness. Key points to consider include:

• The procedure's effectiveness varies considerably among patients, with some experiencing significant relief lasting weeks to months.
• Potential complications, such as temporary numbness, bleeding, infection, and inadvertent puncture of nearby structures, necessitate that the procedure be performed by experienced pain specialists using fluoroscopic or ultrasound guidance.
• Given the global opioid crisis, the AUA guideline advises the judicious use of chronic opioids and recommends preferentially using non-opioid alternatives to manage pain 1. In real-life clinical practice, a ganglion impar block could be a viable option for patients with chronic bladder and pelvic pain who have not responded to conservative treatments, especially when the pain has a neuropathic component or is related to cancer, and after careful consideration of the potential benefits and risks.

From the Research

Ganglion Impar Block for Chronic Bladder and Pelvic Pain

• The ganglion impar block has been shown to be effective in reducing chronic pelvic and perineal pain in several studies 2, 3, 4, 5.
• A study published in 2017 found that repeated ganglion impar blocks resulted in short-term reduction of pain intensity with a moderate intermediate-term effect in 83 patients with chronic pelvic and perineal pain 2.
• Another study published in 2014 reported that neurolytic block of the ganglion impar was effective in managing chronic pelvic pain in nine women, with some patients experiencing complete and permanent cessation of pain 3.
• The use of botulinum toxin type A for ganglion impar block has also been reported to be effective in a case study published in 2010 4.
• A study published in 2018 reported a successful outcome in treating chronic perineal pain using a combination of neurolysis agents and radiofrequency thermocoagulation 5.
• A review of ganglion impar blockade published in 2013 discussed the indications, techniques, and evidence for this pain intervention, highlighting its potential as a treatment option for pelvic and perineal pain 6.

Mechanism of Action

• The ganglion impar is thought to play a role in relaying pelvic and perineal nociceptive messages, making it a therapeutic target for blocking pain signals 2.
• The blockage of the ganglion impar can help to reduce pain intensity by acting on sensitization phenomena 2.

Efficacy and Safety

• The studies reported varying degrees of pain relief, with some patients experiencing complete and permanent cessation of pain 3.
• The procedures were generally well-tolerated, with no complications reported in some studies 3.