Predictors of Voice Improvement After Intracordal Trafermin Injection in Vocal Fold Paralysis

Following intracordal trafermin injection for unilateral vocal fold paralysis, some patients require further treatment owing to poor voice improvement. This study aimed to identify the pre-injection factors predictive of the effectiveness of intracordal trafermin injection for unilateral vocal fold paralysis.

This retrospective study evaluated the medical records of 308 patients diagnosed with unilateral vocal fold paralysis who received intracordal trafermin injections at the Tokyo Voice Center between 2012 and 2024. Data from 143 patients were finally analyzed. To predict the efficacy of intracordal trafermin injection on voice improvement prior to trafermin administration, several related factors were evaluated: age, sex, causative diseases, and pre- and post-injection data, including the maximum phonation time (MPT), pitch range (PR), mean flow rate (MFR), and voice handicap index (VHI). Patients were divided into two groups depending on whether additional treatment was not (Group A) or was (Group B) required after the first injection.

MPT, PR, and MFR differed significantly between Group A and Group B (p < 0.01, 0.02, and 0.01, respectively); subsequently, cutoff values were calculated using these parameters. The cutoff values were 3.25 s for MPT, 20.5 semitones for PR, and 597.8 mL/s for MFR. Logistic regression showed no significant differences in any of the factors.

The pre-injection MPT, PR, and MFR may help guide decisions regarding of intracordal trafermin injection in the treatment of unilateral vocal fold paralysis. These factors could help inform optimal treatment decision making for patients.