What is the role of ganglion impar nerve blocks in the treatment of coccyx pain?

Updated: Jan 07, 2021
  • Author: Patrick M Foye, MD; Chief Editor: Consuelo T Lorenzo, MD  more...
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The ganglion impar (ganglion of Walther) is the terminal ganglion of the paravertebral sympathetic nervous system; it is the only nonpaired sympathetic ganglion. The ganglion impar is usually located anterior to the sacrococcygeal junction, the first intracoccygeal junction, or the first coccygeal vertebra. [30, 31, 32, 33, 34, 35, 36]

One possible mechanism for persistent coccydynia is excessive activity or sensitivity of the ganglion impar, thus creating sympathetically maintained coccyx pain. [11]

Local injection of an anesthetic can effectively block the ganglion impar and thereby relieve coccyx pain. In a published report by Foye and colleagues, nerve blocks using local anesthetics with a fast onset (eg, lidocaine) were shown to provide substantial relief even by the time a patient sat up on the procedure table. [11]

After the local anesthetic block wears off, some of the coccyx pain may start to return, but generally it returns at a much lower severity than existed prior to the injection. Physical medicine and rehabilitation coccydynia physicians and researchers at New Jersey Medical School refer to this new plateau of severity as "resetting the thermostat."

Published reports document that some patients with coccydynia receive complete and permanent relief via a single ganglion impar block. [11]

In patients with less than 100% permanent relief, repeat ganglion impar blocks have been shown to provide additional benefit, further lowering the plateau level of pain. Thus, in patients without complete resolution, repeat injections are often medically necessary and clinically helpful.

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