Femoral and sciatic nerve block for hindfoot and ankle surgery

The use of regional anesthesia, such as ankle block or sciatic nerve block, has gained in popularity due to considerations of patient comfort and safety in foot and ankle surgery. However, if the operation extends above the midfoot or if a thigh tourniquet is required, general or spinal anesthesia is needed. The authors aimed to determine by prospective study whether a 'double block', involving femoral and sciatic nerve blocks, is advantageous under such conditions.

The effectiveness of a preoperative double block was prospectively evaluated in 26 consecutive patients undergoing a variety of foot and ankle procedures, compared with 32 patients with sciatic nerve block alone. Time of analgesia onset, length of block coverage, and complications were noted. Degree of pain was measured using VAS (Visual Analog Scale) scores at the operation, just after surgery, and at 2 h, 1 day, and 2 days after surgery.

The surgical procedures performed under double block were ankle arthroscopy and medial ankle ligament reconstruction, and Achilles tendon repair, and the following conditions were treated; surgery for medial ankle fracture, ankle fusion, subtalar fusion, and surgery for hindfoot diseases, such as, talocalcaneal coalition. The average time required to analgesia onset was 63 min for a double block and 61 min for sciatic nerve block alone. Analgesia time lasted 12.0 h for a double block and 12.4 h for sciatic nerve block alone. Average VAS scores at the operation and immediately after the operation were 0.03 (range 0-1) and 0.16 (range 0-2) for sciatic nerve block, and 0.35 (range, 0-4), 0.31 (range 0-2) for double block. Average VAS scores at 2 h, 1 day, and 2 days postoperatively were 0.28 (range, 0-2), 2.16 (range 0-6), and 1.63 (range 0-5) for sciatic nerve block, and 0.42 (range 0-5), 2.27 (range 0-7), and 1.72 (range 0-8), respectively, for double block.

The results of this prospective study suggest that double block provides good surgical anesthesia and good postoperative pain control for hindfoot and ankle surgery.