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

BACKGROUND: Regional anaesthesia comprising axillary block of the brachial plexus is a common anaesthetic technique for distal upper extremity surgery.
OBJECTIVES: To compare the relative effects of anaesthetic techniques using either single, double or multiple injections for axillary block of the brachial plexus for distal upper extremity surgery. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, as well as reference lists of trials. We contacted trial authors and the medical industry. Date of last search: August 2004. SELECTION CRITERIA: 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 extremity. DATA COLLECTION AND ANALYSIS: We performed independent study selection, quality assessment and data extraction. We undertook meta-analysis, including exploratory analyses according to the method of nerve location and definition of primary anaesthesia failure. MAIN
RESULTS: The 12 included trials involved a total of 981 participants who received regional anaesthesia for hand, wrist, forearm or elbow surgery. Trial design and conduct was generally adequate although several trials failed to monitor longer-term effects and to provide sufficient description of their study populations. Substantial heterogeneity precluded the pooling of data for primary anaesthesia failure from the five trials comparing double versus single injections. However, double injections were significantly more effective than single injections in the three trials where electrolocation was used throughout (relative risk (RR) 0.31, 95% confidence interval (CI) 0.31 to 0.74). Five trials compared multiple with single injections. These showed a statistically significant decrease in primary anaesthesia failure (RR 0.24, 95% CI 0.13 to 0.46) and incomplete motor block (RR 0.61, 95% CI 0.39 to 0.96) in the multiple injection group. Six trials compared multiple with double injections. These showed a statistically significant decrease in primary anaesthesia failure (RR 0.23, 95% CI 0.14 to 0.38) and incomplete motor block (RR 0.55, 95% CI 0.36 to 0.85) in the multiple injection group.Generally, none of the differences between the two groups of any of the three comparisons in secondary analgesia failure, complications and patient discomfort were statistically significant. The time for block performance was significantly shorter for single and double injections compared with multiple injections, but the requirement for supplementary blocks in these groups tended to increase the time to readiness for surgery. AUTHORS'
CONCLUSIONS: This review provided some evidence that multiple injection techniques using nerve stimulation for axillary plexus block provide more effective anaesthesia than either double or single injection techniques. However, there was insufficient evidence for other outcomes, including safety.