Warm or refrigerated local anaesthetic for open carpal tunnel release: a single blind randomized controlled study.

The aim of this randomized controlled study was to determine whether administration of lignocaine with adrenaline is less painful when injected at room temperature compared to refrigerated temperature. A cohort of 50 patients undergoing unilateral carpal tunnel decompression was randomized to room temperature or refrigerated local anaesthetic. Pain scores were assessed using a 10 mm visual analogue scale. Mean pain scores were 4.0 (SD +/- 1.5) for room temperature and 6.5 (SD +/- 1.7) for refrigerated local anaesthetic (P < 0.001). This study demonstrates that patients experience greater pain levels with administration of local anaesthetic at refrigerated temperatures prior to open carpal tunnel release.