What Is A Ganglion Impar Block?
A ganglion impar block is a treatment that is performed to reduce chronic pelvic or rectal pain by blocking nerve impulses. The ganglion impar, also known as the ganglion of Walther or sacroccygeal ganglion, is a bundle of nerve cells that is part of the sympathetic nervous system.
The ganglion impar is located at the sacrococcygeal junction. This bundle of nerves provides the nociceptive and sympathetic supply to the perineal structures, including: the distal rectum, anal region, perineum, distal urethra, distal vagina, and the scrotum or vulva. An over-activity of the ganglion impar can result in chronic coccyx pain. The sympathetic perineal pain is often described as a diffuse, burning sensation, combined with a sense of urgency with urination or defecation.
How Is A Ganglion Impar Block Performed?
The first successful treatment using a ganglion impar block was reported in 1990 by Plancarte et al. He developed the initial anococcygeal approach by using a curved needle that made initial contact with the skin between the anus and coccyx. The needle was then directed anteriorly between the coccyx and rectum. Over the years, the techniques used to perform ganglion impar blocks have evolved to make the procedure more effective and comfortable for the patient.
There are various techniques for ganglion impar blocks, including: the paramedical approach, transoccygeal joint approach, paracoccygeal corkscrew approach, and transsacrococcygeal approach. Although there are a variety of methods for this procedure, the transsacrococcygeal approach is the most commonly used approach as it is effective and simple to perform.
During a transsacrococcygeal procedure the patient has an intravenous line placed that delivers appropriate sedation, if needed. Vital signs, including blood pressure, heart rate, and respiration rate are monitored throughout the procedure. The patient is placed in a prone position on an X-ray table with a pillow placed under their pelvis, which helps to maintain the normal curvature of the spine. The skin is sterilized and a local anesthetic is then utilized to numb the area.
Once the area is sufficiently numb, a thin needle is inserted using fluoroscopic guidance. The needle is then slowly positioned between the sacrococcygeal junction, with the tip of the needle placed just beyond the border of the anterior sacrum. A small amount of contrast dye is then injected to verify the correct needle positioning. The doctor will inject a combination of numbing agent and steroid into the affected nerve site. This type of injection is diagnostic as well as therapeutic. It is expected that patients will report pain relief shortly after having the procedure if the ganglion impar is the real source of their pain.
A current prospective study investigated the results associated with the transsacrococcygeal procedure in 16 consecutive patients. The results showed that the procedure took 12 minutes, on average, to perform and 100% of the patients reported considerable pain relief following the procedure.
Ganglion impar blocks are considered to be a safe and non-invasive treatment; however, as with any procedure, there are some risks for adverse reactions, including: bleeding, infection, nerve injury, allergic reaction, and paralysis. There are no reports of major adverse reactions associated with this procedure mentioned in any medical literature.
Some patients may have an increase in pain and tenderness at the injection site for several days following a ganglion impar block. Additionally, diabetics who undergo this procedure may have elevated blood sugar levels as the result of the injected steroid.
Conditions Related To Ganglion Impar Blocks
The medical literature that is currently available supports the use of ganglion impar blocks for sympathetic or visceral neuropathic perineal pain. A study published in the American Journal of Physical Medicine & Rehabilitation found that one ganglion impar block has the ability to provide complete pain relief of pain in the coccyx region, known as coccydynia. Coccydynia is frequently seen in patients who have fallen directly onto their tailbone. If treatment with anti-inflammatory medication and the use of a donut cushion does not provide pain relief, a ganglion impar block may prove to be effective.
A ganglion impar block may also be effective for treatment of pain that stems from numerous organs, including: the distal rectum, anal region, perineum, distal urethra, distal vagina, scrotum, or vulva.
The underlying causes of sympathetic nervous system pain are complicated and chronic perineal pain in the area of the ganglion impar can be caused by a variety of conditions. Poor blood supply to nerves is often responsible for vascular pain while chronic pancreatitis, non-malignant pain syndromes, cancer of the upper abdomen, rectal cancer, and chronic perineal cancer may result in visceral pain.
There are a number of other conditions that can cause chronic perineal pain including failed spinal surgery, malformation of the spinal cord, and sacral postherpetic neuralgia. Furthermore, in some patient’s perineal pain may be the result of an underlying condition such as an infection (UTI), sexually transmitted disease, or inflammation of the prostate. Before undergoing a ganglion impar block, patients are encouraged to consult with their physician to rule out potential causes of their perineal pain.
Ganglion impar blocks are a safe, non-invasive treatment option for various conditions that affect the areas supplied by the ganglion impar. Patients suffering from chronic pain in any of these regions that has not responded to conventional treatment options may benefit from receiving a ganglion impar block. Various studies have investigated the safety and efficacy of this treatment option and have shown favorable outcomes. Patients are encouraged to speak to their physician to determine if a ganglion impar block will help to provide pain relief for their condition.
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