Single Versus Double Injection Costoclavicular Block

In this trial, the objective is to compare single- and double-injection ultrasound-guided costoclavicular blocks. The rationale behind this idea is that a second local anesthetic injection, inside the costoclavicular space, may compensate for the dynamic cord dispersion seen with the single-injection technique. Thus the research hypothesis is that, compared to its single-injection counterpart, a double injection costoclavicular block will result in a shorter onset time.