Comparison of transthecal digital block and traditional digital block for anesthesia of the finger

Abstract

A randomized, double-blind study was performed in 50 patients to compare the transthecal and traditional subcutaneous infiltration techniques of digital block anesthesia regarding the onset of time to achieve anesthesia and pain during the infiltration. All the patients had sustained injury involving two or four fingers of the hand. Each patient served as his or her own control, having one finger infiltrated with the transthecal technique and the other with the subcutaneous infiltration technique. Time to loss of pinprick sensation and pain (at the time of the infiltration and 24 hours postoperatively) were assessed using a visual analogue scale and verbal response score. A total of 104 blocks (52 transthecal and 52 subcutaneous infiltration) were performed. All of these blocks were successful. Mean time to achieve anesthesia with the transthecal block was 165 seconds, compared with 100 seconds for the subcutaneous infiltration block. The mean analogue pain score was higher for transthecal blocks than for subcutaneous infiltration blocks (3.2 +/- 0.19 versus 1.6 +/- 0.14). Twenty-four hours postoperatively, 24 patients who had the transthecal block experienced pain at the injection site of the digit. However, none of the patients who received the subcutaneous infiltration block complained of pain at the digit. The technique of anesthesia preferred by patients for their finger was the subcutaneous infiltration block, because it causes less pain. Our results confirm the efficacy of the transthecal block for achieving anesthesia of the finger; however, because it is a more painful procedure, it is not recommended.