Comparison of ultrasound-guided supraclavicular and costoclavicular brachial plexus block using a modified double-injection technique: a randomized non-inferiority trial

Ultrasound-guided costoclavicular block (CC-approach) is a recently described brachial plexus block (BPB) and an alternative approach to the supraclavicular approach (SC-approach). The relevant sonoanatomy is analogous in terms of the brachial plexus and its adjacent artery for both approaches. In the present study, we hypothesized that the two approaches will result in similar block dynamics when used the modified double-injection (MDI) technique. One hundred and twelve patients were randomly allocated to receive either a SC- or CC-approach with MDI technique. In the CC group, half the volume was injected adjacent to the medial cord of the brachial plexus, the procedure was guided by ultrasound and verified by nerve stimulator, subsequently the second half was injected close to the lateral cord. In the SC group, the MDI technique was carried out as described in our previous study. Sensory and motor blockade of all four terminal nerves were assessed with a 3-point scale. The primary outcome was the proportion of complete sensory blockade at 15 min with a predefined non-inferiority margin of -13%. The proportion of subjects at 15 min was comparable between the SC group and the CC group (91 vs 87%, absolute difference: -3%). No significant differences were found for complete motor blockade and onset times of the individual nerves within 30 min, and block-related serious adverse events (all P>0.05). We conclude that the MDI technique applied to a costoclavicular and supraclavicular block resulted in similar block dynamics. In addition, it may provide a promising alternative technique when considering the use of multipoint injection.