Regional Anesthesia & Pain Medicine
November/December - Volume 31 - Issue 6 - p 583–584. 2006
Hong, JH, Jang, HS.
Department of Anesthesiology and Pain Medicine, Keimyung University School of Medicine, Dong San Medical Center, Dae Gu, South Korea
The ganglion impar, a solitary retroperitoneal structure, is the termination of the paired lumbar sympathetic trunks. The ganglion impar exhibits anatomic variability of location, and this feature may be the reason for its different success rates. Oh et al. studied the anatomic variability of the ganglion impar, and their study showed that it was located anterior to the lower segment of the first coccyx in 26% of cadavers, and it was anterior to the sacrococcygeal junction in 18% of cadavers. This result implies that the needle for the block of the ganglion impar should be directed toward the lower portion of the first coccyx rather than at the sacrococcygeal junction, the conventional injection site in previous reports. Considering the anatomic proximity of ganglion impar to the lower segment of the first coccygeal bone, this approach is also a viable, alternative method.