Postoperative analgesia with continuous sciatic nerve block after foot surgery: a prospective, randomized comparison between the popliteal and subgluteal approaches

To compare the posterior popliteal and subgluteal continuous sciatic nerve block for anesthesia and acute postoperative pain management after foot surgery, 60 ASA physical status I and II patients undergoing elective orthopedic foot surgery were randomly assigned to either a Subgluteal group (n = 30) or Popliteal group (n = 30). Before surgery and after performing a femoral nerve block with 15 mL of 2% mepivacaine, we performed the sciatic nerveblock with 20 mL of 0.75% ropivacaine using either a subgluteal or posterior popliteal approach, and the placement of a catheter came afterward. In the recovery room, the catheter was connected to a patient-controlled analgesia pump to infuse 0.2% ropivacaine (basal infusion rate of 5 mL/h, incremental bolus of 10 mL, and a lockout time of 60 min). There were no technical problems in catheter placement. Intraoperative efficacy of nerve block was similar in the two groups. Postoperative catheter displacement and occlusion were recorded in four patients in the Popliteal group and two patients in the Subgluteal group (P = 0.677). Both approaches provided similar postoperative analgesia. We conclude that the subgluteal approach is as effective and safe as the previously described posterior popliteal approach for continuous sciatic block and can be considered a useful alternative to anesthesia and acute postoperative analgesia after foot procedures.