Single, double or multiple-injection techniques for axillary brachial plexus block for hand, wrist or forearm surgery in adults.

Regional anaesthesia comprising axillary block of the brachial plexus is a common anaesthetic technique for distal upper limb surgery. This is an update of a review first published in 2006. To compare the relative effects of single, double or multiple injections for axillary block of the brachial plexus for distal upper limb surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE and reference lists of trials. We contacted trial authors. The date of the last search was March 2011 (updated from March 2005). We included randomized controlled trials that compared double with single-injection techniques, multiple with single-injection techniques, or multiple with double-injection techniques for axillary block in adults undergoing surgery of the distal upper limb. We excluded trials using ultrasound-guided techniques. We performed independent study selection, risk of bias assessment and data extraction. We undertook meta-analysis. The 20 included trials involved a total of 2098 participants who received regional anaesthesia for hand, wrist, forearm or elbow surgery. The trial design and conduct were generally adequate although several trials failed to monitor longer-term effects.Eight trials comparing double versus single injections showed a statistically significant decrease in primary anaesthesia failure (RR 0.51, 95% CI 0.30 to 0.85). Subgroup analysis by method of nerve location showed that the effect size was greater when neurostimulation was used rather than the transarterial technique.Seven trials comparing multiple with single injections showed a statistically significant decrease in primary anaesthesia failure (RR 0.28, 95% CI 0.16 to 0.48) and of incomplete motor block (RR 0.61, 95% CI 0.39 to 0.96) in the multiple injection group.Eleven trials comparing multiple with double injections showed a statistically significant decrease in primary anaesthesia failure (RR 0.28, 95% CI 0.20 to 0.40) and of incomplete motor block (RR 0.55, 95% CI 0.36 to 0.85) in the multiple injection group.Tourniquet pain was significantly reduced with multiple injections compared with double injections (RR 0.53, 95% CI 0.33 to 0.84). Otherwise, there were no statistically significant differences between groups in any of the three comparisons on secondary analgesia failure, complications and patient discomfort. The time for block performance was significantly shorter for single and double injections compared with multiple injections. This review provides evidence that multiple injection techniques using nerve stimulation for axillary plexus block produce more effective anaesthesia than either double or single injection techniques. However, there was insufficient evidence for a significant difference in other outcomes, including safety.