THE FEMORAL 3-IN-1 BLOCK REVISITED

Study Objective: To estimate the frequency of successful conduction bl ockade of the femoral, lateral femoral cutaneous, and obturator nerves following a femoral 3-in-1 block. Design: Prospective observational s tudy. Setting: Operating room at Royal University Hospital, Saskatoon, Saskatchewan.Patients: 32 patients having lower extremity surgery. In terventions: Femoral 3-in-1 nerve blocks were performed on all patient s. Measurements and Main Results: Sensation and motor power in all 3 n erve distributions (femoral, lateral femoral cutaneous, obturator) wer e assessed before and after each femoral 3-in-1 nerve block. By our cr iteria, the femoral nerve block was successful in 26 of 32 patients (8 1 %). The lateral femoral cutaneous nerve was successfully blocked in 25 of 26 patients (96%). Incidentally, the saphenous nerve which is cl assically described as the terminal branch of the femoral nerve, was s uccessfully blocked in 20 of 26 patients (77%). The obturator nerve bl ock was successful in only 1 of 26 patients (4%). Conclusions The femo ral 3-in-1 nerve block does not block the parent trunk of the obturato r nerve.