Common practices in botulinum toxin injection for spasmodic dysphonia treatment: A national survey

Objectives/hypothesis: Although no clear guidelines exist, protocols in the treatment of spasmodic dysphonia (SD) vary among physicians. Previously published work comes from relatively few centers.

Study design: A descriptive survey among experts (laryngologists who practice Botulinum toxin injections for SD).

Methods: An online 58-item survey was sent to all otolaryngologists who self-identify as laryngologists on the American Academy of Otolaryngology-Head and Neck Surgery website. Items surveyed included botulinum toxin injection technique, laterality, and dosage.

Results: An 80% response rate was achieved (70 completed the survey). Participants collectively reported treating >4,000 SD patients in the past year (mean, 71 ± 68 patients/laryngologist). Eighty-seven percent perform injections exclusively in the office; the remainder both in the office and operating room. For adductor SD injections, 88% use electromyographic (EMG) guidance alone via cricothyroid approach. The remainder use anatomical landmarks alone (9%) or EMG with endoscopic guidance (3%). Sitting is the preferred patient position (70%; supine, 30%). A substantial majority (87%) begin with bilateral injections (starting dosage mode, 1.25 units/side). For abductor SD injections, 67% use EMG guidance alone and 31% use endoscopic guidance with or without EMG. Sitting is the preferred patient position (84%; supine, 16%). The preferred approach is anterior-translaryngeal (51%), followed by lateral-retrolaryngeal with rotation (34%). A considerable majority (79%) begin with unilateral injections (starting dosage mode, 5 units). When deciding on initial dosage, the most influential factor was balancing patients' desire/needs, followed by patients' frailty and risk of aspiration. The typical planned interval between injections is 3 to 4 months.

Conclusions: Laryngologists follow fairly uniform protocols in the treatment of SD with some important and previously unpublished differences. This study documents areas of agreement and discordance among laryngologists in the United States for the treatment of SD.

Level of evidence: 4 Laryngoscope, 129:1650-1656, 2019.