Combined Saphenous-Sciatic Nerve Blockade Superior to Femoral-Sciatic Nerve Blockade for Postoperative Analgesia Following Foot and Ankle Surgery

Abstract

Introduction: Femoral nerve blockade combined with sciatic nerve blockade has been reported to be an effective treatment regimen for postoperative analgesia following lower extremity surgery.Saphenous nerve blockade is an alternative to femoral nerve blockade for postoperative analgesia in knee arthroplasty surgeryand the level and quality of analgesia that either technique provides patients have been reported to be equivalent. This study compared the postoperative analgesic properties of combined femoral and sciatic nerve blockade with those of combined saphenous and sciatic nerve blockade in patients that underwent foot and ankle surgery. Method: All patients received general inhalational endotracheal anesthesia and were administered lateral popliteal sciatic nerve blockade by a combined nerve stimulator and ultrasound guidance technique in the postoperative recovery area. During the first six months of the study femoral nerve blockade was simultaneously administered employing combined nerve stimulation and ultrasound guidance. During the second six month interval saphenous nerve blockade was administered using ultrasound guidance. Continuous nerve block catheters were inserted if patients were admitted over 24 hours. Breakthrough pain was treated with hydro-morphone patient controlled analgesic infusions. Postoperative pain scores, opioid analgesic consumption and lower extremity movement in the immediate recovery period and at 24 hours after nerve blockade were recorded. Results: 167 patients were enrolled. Femoral nerve blockade was administered to 45 patients and 122 received a saphenous nerve blockade. Immediate pain scores were lower for opioid naïve females that were administered saphenous nerve blockade. All groups that received saphenous nerve blockade had lower opioid requirements in the immediate postoperative period. Differences in pain scores and opioid requirements were noted between opioid naïve and tolerant patient groups. Conclusion: Combined popliteal sciatic and saphenous nerve blockade resulted in lower immediate postoperative pain scores in opioid naïve females and reduced immediate postoperative rescue opioid analgesic dosages in all patient groups. Differences in pain scores and analgesic requirements were not present 24 hours postoperatively. Opioid tolerant patients with effective nerve blockade 24 hours postoperatively required elevated rescue opioid analgesic medication dosages.