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Long-term and Longitudinal Outcomes of Intracordal Trafermin Injection in Vocal Fold Paralysis
Tomohiro Hasegawa1, Retsu Fujita2, Yusuke Watanabe3
1Department of Otolaryngology-Head and Neck Surgery, Gifu University Graduate School of Medicine, Gifu, Japan; Tokyo Voice Center, International University of Health and Welfare, Tokyo, Japan.
Summary
Intracordal trafermin injection (ITI) improves vocal function in unilateral vocal fold paralysis (UVFP) patients long-term. While immediate voice improvements persist, longitudinal data showed minimal clinical impact beyond initial gains.
Area of Science:
- Regenerative Medicine
- Otolaryngology
- Speech Science
Background:
- Intracordal trafermin injection (ITI) shows promise for treating unilateral vocal fold paralysis (UVFP) by promoting tissue regeneration and improving glottal closure.
- Limited long-term and longitudinal data exist regarding the efficacy of ITI in UVFP patients.
- Understanding sustained vocal function post-ITI is crucial for patient management and treatment planning.
Purpose of the Study:
- To evaluate the long-term and longitudinal outcomes of intracordal trafermin injection (ITI) in patients diagnosed with unilateral vocal fold paralysis (UVFP).
- To assess the sustained impact of ITI on key voice parameters including maximum phonation time (MPT), pitch range (PR), mean flow rate (MFR), and voice handicap index (VHI).
- To investigate the correlation between time elapsed since ITI and the degree of voice improvement in UVFP patients.
Main Methods:
- Retrospective analysis of 221 UVFP patients treated with ITI at the Tokyo Voice Center (2014-2025).
- Data collected included patient demographics, ITI dosage, cause of UVFP, and voice metrics (MPT, PR, MFR, VHI) at various time points post-injection.
- Statistical analysis focused on integrated improvements across all patients rather than individual longitudinal changes, using generalized linear mixed-effects models.
Main Results:
- Voice data (MPT, PR, MFR, VHI) demonstrated improvement across all observed periods following ITI.
- No significant correlation was found between the time elapsed after ITI and voice improvement in MPT, PR, MFR, or VHI.
- Longitudinal analysis revealed no significant association between time post-ITI and VHI; while MPT and PR showed significant changes, effect sizes were minimal and not clinically meaningful.
Conclusions:
- Intracordal trafermin injection (ITI) leads to immediate voice improvement in UVFP patients, which is sustained over the long term.
- Despite sustained improvements, longitudinal data did not reveal clinically significant progressive changes beyond the initial recovery phase.
- The findings suggest ITI is effective for initial voice restoration but highlight a discrepancy between sustained objective measures and clinical experience regarding ongoing functional gains.