Comparison of regional nerve block to epidural anaesthesia in day care arthroscopic surgery of the knee.

Day care minimally invasive surgery demands minimal complications with anaesthesia. Nerve blocks are increasingly being employed for surgical procedures on the lower limb, and we attempted to evaluate their benefits and drawbacks in a prospective randomised study in patients undergoing knee arthroscopy. We compared the effectiveness, onset time, duration of analgesia, patient acceptance, failure rate and post-operative comfort of epidural anaesthesia (with 20 ml of 2% lidocaine with adrenaline 1 in 200000) and peripheral nerve blocks (combined 3-in-1 and sciatic nerve block, with 50 ml of 1% lignocaine with adrenaline 1 in 200000, using nerve stimulator). Forty nine cases were randomised to receive either single shot epidural anaesthesia (Group-I, n = 23) or combined 3-in-1 and sciatic nerve block (Group-II, n = 26). The anaesthesia procedure and analgesia onset time was longer in Group-II (p < 0.001), with skin incision being significantly delayed as compared to group-I (45.2+/-6.2min vs 30.0+/-5.4 min respectively) (p < 0.001). Haemodynamic changes were comparable in both groups during the study period. All patients had complete analgesia at skin incision in group-I as compared to 89.1% in group-II (p < 0.05). However 52.2% of patients in group-I required rescue analgesia postoperatively, as compared to only 18.7% in group-II (p < 0.05). We concluded that even though combined 3-in-1 and sciatic nerve block technique has longer anaesthesia induction time, the lesser need for postoperative rescue analgesia, and lesser potential complications like inadvertent spinal puncture, retention of urine and late onset of back pain, make this an attractive option for day care arthroscopy. The use of a nerve stimulator ensures accuracy, patient counselling allows good cooperation, and advance planning can include potential skin incision delays.