Comparison of Botulinum Toxin Injections and Type 2 Thyroplasty for Adductor Spasmodic Dysphonia

Injection of botulinum toxin type A (BTX) into intrinsic laryngeal muscles is the current gold standard therapy for adductor spasmodic dysphonia (AdSD). However, a surgical procedure could potentially offer more stable and long-lasting voice quality to AdSD patients. Here, we report the long-term results of type 2 thyroplasty (TP2) with TITANBRIDGE® (Nobelpharma, Tokyo, Japan) compared with those of BTX injections.

In total, 73 AdSD patients visited our hospital between August 2018 and February 2022. Patients were provided the option of BTX injections or TP2. They were assessed via the Voice Handicap Index (VHI)-10 before treatments and at scheduled clinical follow-ups at 2, 4, 8, and 12 weeks for BTX and at 4, 12, 26, and 52 weeks for TP2.

Overall, 52 patients selected the BTX injection and had a pre-injection mean VHI-10 score of 27.3 ± 8.8. Following injections, the scores significantly improved to 21.0 ± 11.1, 18.6 ± 11.5, and 19.4 ± 11.7 at 2, 4, and 8 weeks, respectively. There were no significant differences between the pre-injection scores and the 12-week scores (21.5 ± 10.7). Alternately, 32 patients opted to be treated with TP2 and had a pre-treatment mean VHI-10 score of 27.7. All patients reported an improvement in their symptoms. Additionally, the mean VHI-10 score significantly improved to 9.9 ± 7.4 at 52 weeks following treatment. There was a significant difference between the two treatment groups at 12 weeks. Some patients received both treatments.

These preliminary results provide important insights into the value of TP2 as a potential permanent treatment for AdSD patients.

3 Laryngoscope, 133:3443-3448, 2023.