Background

The ultrasound-guided costoclavicular block provides surgical anaesthesia for procedures involving the elbow, forearm and hand by targeting the closely clustered cords of the brachial plexus. However, it remains uncertain whether depositing local anaesthetic at two sites improves block characteristics compared with a single central injection. This study compared the efficacy and safety of single-site and two-site ultrasound-guided costoclavicular blocks for below-elbow surgery.

Methods

This prospective, randomized, assessor-blinded study included 72 adults undergoing elective below-elbow surgery. Participants were allocated equally to single-site (n=36) or two-site (n=36) costoclavicular block. Both groups received 30 mL of 0.5% ropivacaine. In the single-site group, the entire volume was deposited centrally among the three cords. In the two-site group, 15 mL was injected centrally and 15 mL at the medial cord–arterial interface. The primary outcome was composite sensorimotor block-onset time. Secondary outcomes included performance time, readiness for surgery, block success, analgesic duration, postoperative pain, patient satisfaction and adverse events.

Results

Two-site injection required longer performance time (6.5±1.2 versus 5.7±1.0 minutes; p=0.003) and more needle passes (median 2 versus 1; p<0.001). Nevertheless, it significantly shortened sensory onset (14.4±4.8 versus 18.9±5.7 minutes; p=0.001), motor onset (16.5±5.2 versus 21.7±6.1 minutes; p<0.001) and composite onset (16.8±5.5 versus 22.3±6.4 minutes; p<0.001). Total anaesthesia-related time was shorter with two-site injection (23.3±5.8 versus 28.0±6.5 minutes; p=0.002). More two-site recipients were ready for surgery by 15 minutes (52.8% versus 22.2%; p=0.007) and 20 minutes (80.6% versus 55.6%; p=0.023). Final surgical success was comparable (97.2% versus 94.4%; p=1.000). Block duration, postoperative analgesia, satisfaction and adverse-event rates did not differ significantly.

Conclusion

Two-site ultrasound-guided costoclavicular block accelerated sensorimotor onset and surgical readiness compared with single-site injection, although it required slightly longer performance time and additional needle manipulation. Both techniques provided comparable final success, analgesic duration and safety.