Digital anaesthesia: comparison of the efficacy and pain associated with three digital nerve block techniques

There are three commonly used methods of digital block anaesthesia: viz. subcutaneous, metacarpal and transthecal. A randomized, single-blinded study on 50 healthy volunteers was performed to determine time to onset, pain level and preference. Volunteers each received all three blocks, serving as their own controls. Time to onset was significantly longer (P<0.001) for the metacarpal block than for the subcutaneous or transthecal blocks. There was no significant difference in average pain level between the methods, as measured on a scale from 1 to 10. Volunteers chose the subcutaneous block (43%) as their first choice over the metacarpal block (33%) or the transthecal block (25%). The transthecal block had prolonged discomfort lasting 24 to 72 hours after injection in 20 subjects (40%). These findings suggest that subcutaneous block is effective and preferred by healthy volunteers for digital anaesthesia.