Investigation of Predictors for Voice Improvement after Intracordal Trafermin Injection in Unilateral Vocal Fold Paralysis

Bckground: With regard to intracordal trafermin injection for unilateral vocal fold paralysis, some patients require further treatment due to poor voice improvement, and their preoperative factors are unknown.

Methods: We retrospectively studied the medical records of 75 patients diagnosed with unilateral vocal fold paralysis and who underwent intracordal trafermin injection at our institution from 2014 to 2017. Age, preoperative maximum phonation time, pitch range, mean flow rate, Voice Handicap Index, and pre- and postoperative changes in these parameters were included in the evaluation.

Results: Significant differences were found in the pitch range and mean flow rate before injection. The cutoff values were calculated to be 17.5 semitones for the pitch range and 972.1 ml/sec for the mean flow rate. A significant difference was found in the maximum phonation time by the amount of change before and after the injection.

Conclusion: For unilateral vocal fold paralysis, the pitch range and mean flow rate on preoperative voice testing are predictors of voice improvement efficacy, and postoperative improvement in maximum phonation time may be an indicator of re-treatment. The optimal treatment plan for the patient should be determined based on these factors.