Comparison of transthecal and subcutaneous single-injection digital block techniques.

A randomized double-blinded study was performed on 20 normal volunteers to evaluate 2 different techniques of single-injection digital anesthesia. Single-injection transthecal digital block technique was used to anesthetize 1 index finger and single-injection subcutaneous technique to block the other index finger. Pain and light touch were evaluated and sensory nerve-conduction studies were performed on both index fingers. These data were obtained prior to the nerve blocks and then at 10-minute intervals until recovery from the anesthesia. The method of anesthesia was found to have no effect on the distribution, onset, and duration of anesthesia. Median and radial nerve sensory nerve action potential amplitude reductions following digital anesthesia were also not influenced by the technique of anesthesia. Single-injection subcutaneous block was found to be easier to administer and to produce less pain during and 24 hours after injection than did the single-injection transthecal technique.