We report a study which shows that the traditional transthecal injection technique provides poor correctness but stable anesthetic effects. We investigated whether a small quantity of anesthetic is effective or leakage into the subcutaneous tissue is effective. Accurate transthecal injection technique was necessary to examine how the technique affects transthecal digital block.
An injection study using contrast medium and lidocaine was performed on the middle fingers of healthy volunteers. Our new transthecal injection technique involved inserting a needle at the palmophalangeal crease, penetrated the flexor tendon to the proximal phalanx, without withdrawing the needle during injection.
We believe that the success rate of traditional transthecal injection technique is very low due to the use of loss of resistance by withdrawing the needle.
This technique allows comparison of anesthetic effects between the transthecal digital block and subucutaneous digital block.