Assessment of procedures and instruments for intracordal injection: evaluation of the syringe for periodontal ligament anesthesia (CITO JECT).

The intracordal injection technique was first introduced by Brünings in 1911. This technique has been accepted as vocal rehabilitation for dysphonia caused by deficiencies of glottal closure. Although various injection materials have been evaluated, the injection procedure itself has not been studied. In this study, we measured the mechanical force required to perform intracordal injection by using a certain amount of substance, when varying the needle size and syringe type. Although a large needle can reduce the mechanical force for injection, leakage from the pinhole can not be prevented. We modified this technique by introducing a CITO JECT, a syringe, which is used for the anesthesia of the periodontal ligament, to perform the collagen injection. With this technique, the mechanical force required for the injection can be reduced to 1/2 to 1/4 of the force by the conventional technique. We conclude that the introduction of this syringe enable us to use the needle with smaller diameter to facilitate the intracordal injection.