[Evaluation criteria for 3-in-1 anesthetic block: Is the involvement of the obturator nerve common?].

BACKGROUND AND OBJECTIVES The participation of the obturator nerve in 3:1 blockades is controversial. Superficial surgical interventions in the medial face of the thigh strike femoral and obturator nerves dermatomes with imprecise, overlapped or even absent limits. The correlation between clinical outcome and other diagnostic methods may be conclusive about the involvement of the obturator nerve. CONTENTS In general, regional block outcomes are confirmed more by the lack of dermatome sensitivity than by miotomes motor activity. As from the anatomic understanding of the pathway of plexus components of 3:1 blocks, clinical criteria aided by other diagnostic methods explain obturator nerve involvement. CONCLUSIONS The symbiosis between 3:1 block outcome and different diagnostic methods is interpretative and conclusive and, according to literature indications about the obturator nerve participation, 3:1 block with single injection does not justify its name.