Regional anaesthesia on the finger: Traditional dorsal digital nerve block versus subcutaneous volar nerve block, a randomized controlled trial

Abstract

To identify the most comfortable digital nerve block by comparing painfulness and efficiency of two commonly used digital nerve blocks: the volar subcutaneous nerve block and the traditional dorsal nerve block. Patients, age ≥ 18 years, presenting with an injury of the finger requiring regional anaesthesia were included. Patients were blindly randomized in receiving the one-injection subcutaneous volar nerve block (intervention group) or the two-injection traditional dorsal digital nerve block (control group). Primary outcome measure was discomfort of the injection. Secondary outcome measures were extent of anaesthesia in different regions of the finger, complication rate and satisfaction of the clinician. In total, 409 patients were randomly allocated to the intervention group (N=209) or control group (N=200). Discomfort of the injection was not different between both anaesthetic techniques. The mean pain score (Numerical Rating Scale - NRS) of the intervention group was 4.57 (range 0 - 9, CI 4.27 - 4.87, SD 2.18). The mean pain scores of the control group were 4.63 for the first injection (range 0 - 10; CI 4.28 - 4.99, SD 2.36) and 4.51 for the second injection (range 0 - 10; CI 4.14 - 4.87, SD 2.44). The traditional dorsal digital nerve block was better in anesthetizing the dorsal side of the finger. The subcutaneous volar nerve block was better or equivalent in terms of extent of anaesthesia on the volar side of the finger. In patients requiring digital anaesthesia in the Emergency Department, the anaesthetic technique affects both the discomfort of the injection and extent of anaesthesia. The traditional dorsal digital nerve block is preferred for dorsal injuries. The subcutaneous volar nerve block is preferred for volar injuries.