A comparative study between single injection (corner pocket approach) and double injection costoclavicular block: A randomized parallel arm, non-inferiority trial

Abstract

Background

Previous studies have shown that ultrasound guided costoclavicular block may require a double shot to provide adequate, rapid sensory and motor blockade. In this trial, we hypothesized that if the corner pocket approach (between axillary artery and median cord) is used instead of the central approach (at the midpoint of the 3 cords) when performing single-shot costoclavicular block, the onset of blockade would be non-inferior to the double-shot technique.

Method

Ninety patients undergoing upper limb surgery were randomized to 2 groups for ultrasound-guided costoclavicular block (CCB) at a tertiary hospital. One group received ultrasound guided single-shot CCB using the corner pocket approach and other received ultrasound guided double-shot – the first shot at the centre of the 3 cords and the second between the axillary artery and the median cord. An observer blinded to group assignment recorded blockade onset time (defined as the time required to achieve a minimal sensorimotor composite score of 14 out of 16 points).

Results

Of the 101 patients assessed for eligibility, 90 were recruited over period of 1 year (February 2022 to January 2023), with 45 in each group. Onset time was 22.1 ± 3.1 min in the single-shot group and 22.4 ± 2.9 min in the double-shot group. This difference was insignificant (P = .3).

Conclusion

Time to onset of blockade and full anaesthesia are similar in single-shot corner pocket CCB vs double-shot CCB. Further studies are required to determine the minimum effective volume of local anaesthetic required for the described technique.