[Sciatic nerve block with 1% mepivacaine for foot surgery: posterior versus lateral approach to the popliteal fossa]. / Estudio comparativo del bloqueo del nervio ciático en el hueco poplíteo por abordaje posterior frente al abordaje lateral con mepivacaína al 1% para cirugía del pie.

AIMS: To compare the efficacy and feasibility of the sciatic nerve block performed using either a posterior or a lateral approach to the popliteal fossa, taking into consideration patient comfort during puncture and postoperative analgesia. PATIENTS AND METHODS: Sixty patients scheduled for foot surgery were randomly assigned to 2 groups: a posterior approach was used in performing the sciatic nerve block in 1 group (n = 30) and a lateral approach was in the other group (n = 30). The local anesthetic employed was mepivacaine 1%. RESULTS: Duration of sensory block was used significantly longer with the lateral approach (5.4 hours, range 3.3-8 hours) than with the posterior approach (4.4 hours, range 1.5-7 hours) (P < 0.001). Time to onset of the block was significantly shorter with the lateral approach (10 minutes, range 5-25 minutes) than with the posterior approach (17 minutes, range 4-45 minutes) (P < 0.01). Quality of the blockade was similar with both approaches. CONCLUSIONS: The lateral approach to the block of the sciatic nerve in the popliteal fossa provides analgesia comparable to that obtained with the posterior approach, with a faster onset and longer postoperative duration.