Blockade of the Ganglion Impar (Walther), Using Ultrasound and a Loss of Resistance Technique

Abstract

The ganglion impar is an unpaired sympathetic structure located at the level of the sacrococcygeal joint. Blockade of this structure has been utilised to treat chronic perineal pain. Methods to achieve this block often involve the use of fluoroscopy which is associated with radiation exposure of staff involved in providing these procedures. We report a combined loss of resistance injection technique in association with ultrasound guidance to achieve the block. Ultrasound was used to identify the sacrococcygeal joint and a needle was shown to enter this region. Loss of resistance was then used to demonstrate that the needle tip lies in a presacral space. The implication being that any injectate would be located in an adequate position. The potential exception would be a neurodestructive procedure as radiographic control of needle tip in relation to the rectum should be performed and recorded. However when aiming for a diagnostic or local anaesthetic based treatment option we feel that this may become an accepted method.

Clinical efficacy of ultrasound-guided pulsed radiofrequency combined with ganglion impar block for treatment of perineal pain

“…Firstly, in our study, the ultrasound-guided method was roughly consistent with that reported by Johnston et al [ 16 ]. Local, clear ultrasonograms were obtained by Johnston et al [ 16 ], who used high-frequency probes.…”

“…Firstly, in our study, the ultrasound-guided method was roughly consistent with that reported by Johnston et al [ 16 ]. Local, clear ultrasonograms were obtained by Johnston et al [ 16 ], who used high-frequency probes. In our study, significant thickening of subcutaneous soft tissues in the sacrococcygeal area in obese patients prevented clear visualization of the sacrococcygeal joint because of insufficient penetration of the ultrasound waves when using a high-frequency probe.…”

“…In addition, high-frequency ultrasound is usually used to evaluate muscles, tendons, ligaments, and peripheral nerves in clinical practice, and also in the field of pain therapy[ 14 ]. Ultrasound-guided ganglion impar blocks were first reported by Gupta et al [ 15 ] in 2008 and became an effective treatment for chronic perineal pain[ 7 , 16 ]. However, real-time ultrasound-guided GIB-PRF for treating perineal pain was rarely studied.…”

Evidence-based clinical practice guidelines for interventional pain management in cancer pain

“…Ganglion Impar or Walther is an unpaired structure located at the termination of bilateral lumbosacral sympathetic chains and supplies nociceptive and sympathetic fibers to the perineum, distal rectum, perianal region, distal urethra, vulva/scrotum, and the distal third of the vagina. [ 72 73 74 ] It is a retroperitoneal structure located at or slightly below (up to 2 cm) the sacrococcygeal junction. [ 75 ] It is the sustained visceral sympathetically mediated perineal pain which is amenable for ganglion impar block.…”

“…[ 79 ] Other approaches described in the literature include transsacrococcygeal and transdiscal approach. [ 72 80 ] However, fluoroscopic confirmation of retroperitoneal needle tip location and appropriate dye spread (Comma sign produced by 1–2 ml of radiographic contrast medium) is a must before injection of neurolytic agents (6% phenol) when USG is used as the primary imaging modality. [ 72 79 81 ] The closer the needles tip to the rectum, the lower the volume of neurolytic agent (1–8 ml) that should be injected.…”