Although no guidelines concerning discharge criteria after axillary plexus block are available, many institutions consider recovery of motor function as a critical factor.With the midhumeral approach, the four main nerves of the upper extremity can be blocked separately using a peripheral nerve stimulator. The aim of this double-blind study was to block the radial (R) and musculocutaneous (MC) nerves with lidocaine, and the median (M) and ulnar (U) nerves with bupivacaine to recover motor function of the elbow and wrist more rapidly while maintaining long-lasting postoperative analgesia at the operative site. Patients undergoing surgery for Dupuytren's contracture were randomized into two groups in a double-blind fashion: in the control group (n = 17), each of the four nerves was infiltrated with 10 mL of a mixture of 2% lidocaine and 0.5% bupivacaine, whereas in the selective group (n = 17), the R and MC nerves were blocked with 10 mL of 2% lidocaine each and the M and U nerves were blocked with 10 mL of 0.5% bupivacaine each. Recovery of motor block was significantly faster in the selective group (231 +/- 91 vs 466 +/- 154 min). However, time to first sensation of pain was not different between groups (707 +/- 274 vs 706 +/- 291 min). In conclusion, this new approach at the midhumeral level enables the anesthesiologist to selectively administer local anesthetics on different nerves. Implications: In outpatients undergoing surgery for Dupuytren's contracture, a midhumeral block was used with the musculocutaneous and radial nerves blocked by lidocaine and the median and ulnar nerves blocked with bupivacaine. Recovery of motor function and time to discharge were shorter compared with patients who received the mixture on all four nerves.
(Anesth Analg 1998;86:746-8)