[Sciatic nerve block with 1% mepivacaine for foot surgery: posterior versus lateral approach to the popliteal fossa].

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.