Long-term quantitative results of an Isshiki type 4 thyroplasty-a case study.

Objective: We believe that we have described the first instance of long-term follow-up of a bilateral Isshiki type IV thyroplasty in a 58-year-old woman after bilateral superior laryngeal nerve (SLN) damage.

Method: Comparison of voice handicap index-10 (VHI-10) questionnaire and electrolaryngographic measurements pre- and post-thyroplasty (type IV).

Results: VHI-10 scores reduced from 25 pre-thyroplasty to seven and five at 6 and 34 months, respectively. Mean, mode, and median dynamic frequency range (DFx-1) scores increased from 118, 125, and 124 Hz preoperatively to 144, 172, and 163 Hz at 6 months and 167, 167, and 169 Hz, at 34 months, respectively (a subjectively higher voice). Range of tones produced while speaking reduced from an 80% range of 2.48 octaves and 90% range of 3.52 octaves to scores of 1.46 and 2.75 octaves for 80% and 90%, respectively at 6 months and 0.82 and 1.73 octaves at 34 months (a more defined voice). Ninety percent spectrum of single tone production increased from 0.17 octaves preoperatively to 0.55 octaves at 6 months and 0.49 octaves at 34 months.

Discussion: Type IV thyroplasty is most commonly performed for the male-to-female transsexual patient. Bilateral SLN palsy can be effectively treated with this approach with good long-term results.

Conclusion: Three-year follow-up for bilateral type IV thyroplasty reveals increased pitch, definition, and clarity but decreased range overall.