Prospective randomized study of a new method of providing postoperative pain relief following femoropopliteal bypass.

Abstract

The extensive incision required for femoropopliteal bypass using saphenous vein causes significant postoperative pain, principally within the distribution of the cutaneous branches of the femoral nerve. This prospective randomized study investigated the efficacy of continuous postoperative femoral nerve block in reducing both pain (visual analogue pain score) and the requirement for opiate analgesia. Ten patients received a femoral nerve block by infusion of 0.5 per cent bupivacaine (5 ml/h for 48 h) via an epidural catheter together with a patient-controlled analgesia (PCA) device containing morphine; a further ten patients used a PCA device alone. The median postoperative intravenous morphine requirement was significantly reduced in patients with a nerve block at 24 h (4 versus 33 mg, P < 0.01) and at 48 h (5 versus 37 mg, P < 0.01) compared with controls. Postoperative pain was effectively abolished in the former group. The addition of a nerve block to PCA provides superior pain control after femoropopliteal bypass.