Brief reports: ultrasound-guided obturator nerve block: a proximal interfascial technique.

Abstract

In this report, I describe and evaluate a proximal ultrasound (US)-guided obturator nerve block technique using an interfascial local anesthetic (LA) injection deep to the pectineus muscle. The pectineus muscle was identified and followed, while the US probe was tilted cranially until the superior pubic ramus was visualized. In this plane, LA was injected interfascially between the pectineus and obturator externus. The median time required to identify the injection site was 4 seconds (95% confidence interval, 3-5 seconds). The median motor block onset was 4 minutes (95% confidence interval, 3-5 minutes). Both obturator nerve branches were blocked successfully in all patients (100%). The US-guided obturator nerve block using interfascial LA injection inferior to the superior pubic ramus, between the pectineus and obturator externus muscles, was shown to be a simple and successful technique.