The Anesthetic Effect of Modified Subcutaneous Single-Injection Digital Block.

Abstract

Purpose: The aim of this study is to investigate the anesthetic effect on a modified subcutaneous single-injection digital block in accordance with the location of the finger. Method: We recruited volunteers from the workshop training course. We injected less than 5 mL of 2% lidocaine at the volar side, between the 3rd metacarpal and proximal phalangeal joint, until the swelling in the dorsal side of the finger increased. At 10 minutes post the modified subcutaneous single-injection digital block, we recorded the pain score (0-10) using 11-point numeric rating pain scale (NRPS) according to the location of the finger (volar proximal phalanx, VPP: volar middle phalanx, VMP: volar distal phalanx, VDP: dorsal distal phalanx, DDP: dorsal middle phalanx, DMP: dorsal proximal phalanx, DPP) via a pinprick test. We analyzed and compared the NRPS on the location of the finger by the Friedman test with a Pairwise comparison. Results: Fifty-eight volunteers of healthy adult were enrolled in this study. The pain scales on DPP and DMP were 7.00 (4.00-8.00) and 2.00 (1.00-4.00), respectively. The pain scales on DDP, VDP, VMP and VDP were 0.00 (0.00-2.00), 0.00 (0.00-0.00), 0.00 (0.00-1.00) and 0.00 (0.00-1.00), respectively. The pain scales on DPP and DMP were significantly different among DDP, VPP, VMP and VPP (p<0.05). There were no significant differences of pain scale on DDP, VDP, VMP and VPP (DDP vs. VDP, p=0.592: DDP vs. VMP, p=0.749: DDP vs. VPP, p>0.999: VDP vs. VMP, p>0.999: VMP vs. VPP, >0.999). Conclusion: A modified subcutaneous single-injection digital block should be considered useful in regional anesthesia at the volar side of the finger and the dorsal side of the distal phalanx.