Endoscopic Laser Thyroarytenoid Myoneurectomy in Botulinum Toxin-Refractory Adductor Spasmodic Dysphonia: A Case...

Spasmodic dysphonia (SD) is a focal laryngeal dystonia characterized by involuntary phonatory interruptions and a strained-strangled voice quality. Although botulinum toxin injection remains the current standard of care, its transient therapeutic effect and the requirement for repeated administrations limit sustained disease control in a subset of patients. This study aimed to evaluate the short-term clinical outcomes of endoscopic laser thyroarytenoid (TA) myectomy combined with selective neurectomy of recurrent laryngeal nerve branches using a specially designed electrosurgical device in patients with SD.

Between 2021 and 2022, 28 consecutive patients with SD underwent endoscopic laser TA myoneurectomy. Surgical outcomes were assessed according to postoperative complications, subjective voice measures, acoustic voice analyses, and videostroboscopic findings. Six-month follow-up data were available for 14 patients.

The study cohort comprised four men (14.3%) and 24 women (85.7%), with a mean age of 35.9 years (range, 22-50.1 years). No cases of postoperative vocal fold paralysis were identified. Transient postoperative granulation developed in four patients and resolved within one month, and one patient reported postoperative odynophagia. The mean Voice Handicap Index score improved significantly from 92.62 ± 13.54 to 58.31±25.99 (adjusted P = 0.011), and 78.6% of patients reported ≥90% subjective improvement. Significant postoperative improvements were also observed in jitter (from 1.93 ± 1.69% to 1.03 ± 0.74%, adjusted P = 0.014), shimmer (from 6.49 ± 5.40% to 3.28 ± 1.85%, adjusted P = 0.011), and the cepstral spectral index of dysphonia derived from sustained vowel samples (from 40.15 ± 33.50 to 11.78 ± 18.81, adjusted P = 0.011) and connected speech samples (from 89.40 ± 27.24 to 19.49 ± 11.89, adjusted P = 0.029). Videostroboscopic evaluation demonstrated improvement in glottal compression, anteroposterior glottal compression, and overall vocal strain.

Endoscopic laser TA myoneurectomy yielded favorable short-term voice outcomes with an acceptable safety profile. This surgical approach may represent an effective second-line therapeutic option for patients with SD who demonstrate resistance to botulinum toxin or poor compliance with repeated injection therapy.