Ganglion Impar Block

Ganglion Impar Block

A. Indications

Ganglion impar block is effective for patients with visceral or sympathetically maintainedpain in the perineal area.

B. Anatomy

The ganglion impar (ganglion of Walther) is the most caudal part of the sympathetic trunks. The two lowest pelvic sympathetic ganglia often fuse form-ing one ganglion in the midline just anterior to the coccyx.

C. Technique

The patient may be positioned in the prone, lateral decubitus, or lithotomy position. A 22-gauge needle is advanced through the sacrococcygeal ligament and the rudimentary disc into a position just anterior

to the coccyx. This procedure can be facilitated with fluoroscopy or ultrasound. Radiofrequency ablation, or in some cases a neurolytic injection, may provide longer duration of analgesia for this sympathetically mediated pain.

D. Complications

Intravascular injection and transient bowel or blad-der dysfunction are possible. Alternative approaches involve placement of the needle through the ano-coccygeal ligament, although these may have higher potential to perforate the rectum.