Revisiting the anatomy of the ilio-inguinal/iliohypogastric nerve block

Abstract

BACKGROUND : The ilio-inguinal/iliohypogastric nerve block (INB) is one of
 the most common peripheral nerve block techniques in pediatric anesthesia,
 which is largely due to the introduction of ultrasound (US) guidance. Despite
 the benefits of US guidance, the absence of an US machine should not deter
 the provider from performing INB, considering that many institutions, especially
 in developing countries, cannot afford to provide ultrasound machines
 in their anesthesiology departments. The aim of this study was to revisit the
 anatomical position of the ilio-inguinal and iliohypogastric nerves in relation
 to the anterior superior iliac spine (ASIS), in a large sample of neonatal
 cadavers, and compare the results with a similar group in a previously published
 US-guided study.
 METHODS : With Ethics Committee approval, the ilio-inguinal and iliohypogastric
 nerves were carefully dissected in 54 neonatal cadavers.
 RESULTS : In the total sample, the ilio-inguinal nerve was found to be
 2.2 1.2 mm from the ASIS, on a line connecting the ASIS to the umbilicus.
 The iliohypogastric nerve was on average 3.8 1.3 mm from the ASIS. For
 the entire sample, the optimal needle insertion site was 3.00 mm from the
 ASIS. Although there is a strong correlation between the needle insertion point
 and the weight of the neonate, this will only ‘fit’ for 60%of the population.
 CONCLUSION : The linear regression formula; needle insertion distance
 (mm) = 0.6 9 weight + 1.8 can be used as a guideline for the position of the
 ilio-inguinal and iliohypogastric nerves.

http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1460-9592

hb2013