Two common methods of digital nerve block are the two injection dorsal webspace approach and the single injection volar subcutaneous approach. To date, no study has directly compared these two widely used approaches in terms of discomfort, reliability, duration, and patient preference.

With informed consent and Ethics Committee approval, 27 volunteers underwent randomly dertermined injections of the long finger of each hand with 1.8 cc of 2% xylocaine with 1/100 000 epinepherine. The two injection dorsal method (0.9 cc per injection) was used on one finger, and the other received the single volar injection. After each injection the volunteers rated their discomfort on a visual analog scale. When both injections were completed the subjects indicated their preferred approach. The distribution of anesthesia was mapped and the digits photographed. Duration of anesthesia was reported as the time when normal sensation returned to the fingertip.

Eighty-one percent of volunteers indicated that they would choose the single volar injection technique over the two injection dorsal technique if they were given the choice in the future. The average discomfort for the volar approach was 4.1/10, and 4.5/10 for the dorsal approach (statistically insignificant difference). Duration of anesthesia averaged 7 hours for the volar approach and 5 hours for the dorsal approach. The volar technique was felt to provide more rapid and complete anesthesia of the digit, with less adjacent digit numbness. No adverse effects were reported.

This study has shown that the single injection volar subcutaneous digital block is more reliable, has longer duration of anesthesia, and, contrary to popular belief, is not significantly more uncomfortable than the two injection dorsal webspace approach. These characteristics have made it our preferred technique for digital blocks.