Comparison of Techniques in Transthecal and Subcutaneous Single Injection Digital Nerve Block at Palmophalangeal Crease

Injection study using contrast medium and lidocaine was performed on the 16 middle fingers of normal volunteers to evaluate correctness of injection techniques. We used two different single injections at the palmophalangeal crease; subcutaneous and transthecal. Agent location was evaluated by roentgen studies.The success rate of the subcutaneous injection was 100%. With the transthecal injection, we found agents inside and outside the tendon sheath in all cases. Success rate was therefore 0 %.Since the transthecal digital block was first introduced by Chiu in 1990, many authors have described the anesthetic effect as satisfactory. But the transthecal digital block technique presents considerable concern. The mechanism of the single injection transthecal digital block was concluded as unclear in this study.