Better Outcome After Thyroplasty Type I in Unilateral Vocal Fold Paralysis Without Synkinesis and Synkinetically-Reinnervated Type IV Vocal Fold Paralysis

Importance:

Thyroplasty type I is considered standard therapy in patients with chronic unilateral vocal fold paralysis (UVFP); revisions are frequently required.

Objective:

The aim of the study was whether synkinesis affects thyroplasty type I.

Design:

Retrospective data analysis.

Participants:

Patients with UVFP (age ≥18 years) after thyroplasty type I.

Intervention of exposures: Between November 2019 and November 2022, 28 patients with chronic UVFP underwent thyroplasty type I and were followed up 6 months postoperatively. Prior to surgery, all patients underwent laryngeal electromyography (LEMG).

Main outcome measures:

Dysphonia Severity Index (DSI), perceptual voice sound analysis (GRBAS), voice acoustics (jitter %), maximum phonation time (MPT), voice range profile measurements (VRP), Voice Handicap Index (VHI-9), and laryngo(strobo)scopic findings were assessed preoperatively and up to 6 months after thyroplasty. For study purposes, the presence of synkinesis was retrospectively evaluated and classified according to the Crumley classification based on preoperative data. Statistical analyses were exploratory. A linear mixed-effects model was used to asses preoperative and postoperative DSI in patients with and without synkinesis. Statistical analyses were carried out with SPSS version 27.

Results:

Sixteen patients had a UVFP without and 12 with synkinesis. Among patients with synkinesis, 25% were classified as Crumley type II, 50% as type IV, and 25% as undefined. DSI improved significantly postoperatively across all patients ( P  = .006). The greatest improvement in GRBAS score, MPT, and Jitter (%) were observed in UVFP patients with type IV and those without synkinesis. VHI-9 scores improved in patients with type IV synkinesis (n = 6) and those without synkinesis (n = 16). Complete glottal closure was achieved in most patients with (n = 7) and without synkinesis (n = 12).

Conclusion:

This study emphasizes the importance of preoperative LEMG in chronic UVFP before thyroplasty type I to identify unfavorable synkinesis types, as routine laryngo(strobe)scopy and voice acoustic evaluation do not allow any conclusion on aberrant reinnervation processes.

Relevance:

Patients with type IV are suitable candidates for thyroplasty type I. In type II and undefined synkinesis, thyroplasty type I alone is insufficient, and additional therapies should be considered.