400 Section - The Efficacy and Safety of Real-Time Ultrasound-Guided Laryngeal Electromyography: A Prospective, Single-Arm, Pilot Study

This study evaluated the efficacy and safety of real-time ultrasound-guided laryngeal electromyography (EMG).

Design:

In this prospective, single-arm pilot study, sixteen consecutive patients aged 18–80 years referred for laryngeal EMG (February 21–June 26, 2025) were enrolled. Patients with prior neck surgery that could impede EMG needle insertion were excluded. For the ultrasound procedure, patients were positioned supine with neck extension. Four ultrasound views were obtained: midline longitudinal (cricothyroid membrane view), midline transverse (bilateral vocal cord view) (Figure 1a), lateral transverse (unilateral vocal cord view) (Figure 1b), and lateral oblique (needle trajectory view) (Figure 1c). Under ultrasound guidance, the needle was inserted through the cricothyroid membrane, avoiding penetrating the airway, until it reached the TA muscle. Visualization of relevant laryngeal structures, needle position, thyroid cartilage calcification, and adverse events were documented.

Results: A total of 44 muscles were examined, including 31 thyroarytenoid (TA) muscles and 13 cricothyroid (CT) muscles. The most frequent complaints were hoarseness (n=5, 31.3%), dysphagia (n=5, 31.3%), and combined hoarseness with dysphagia (n=5, 31.3%), whereas dysarthria was reported in one patient (6.3%). Etiologies included brainstem stroke (n=4, 25.0%), iatrogenic surgical injury (n=3, 18.8%), idiopathic neuropathy (n=2, 12.5%), and endotracheal intubation–related injury (n=1, 6.3%); one patient (6.3%) was diagnosed with amyotrophic lateral sclerosis. Based on EMG, recurrent laryngeal neuropathy was present in seven patients (43.8%), combined recurrent and superior laryngeal neuropathy in four (25.0%), and no definite abnormalities in five (31.3%). Feasibility of ultrasound-guided EMG was confirmed in all enrolled patients. Procedural success, defined as needle trajectory visualization in the ultrasound and acquisition of analyzable EMG signals from the targeted muscles, was achieved in all examined muscles. Cough occurred in three patients (18.8%), despite avoidance of airway penetration.

Conclusion:

Real-time ultrasound-guided laryngeal EMG is a feasible and safe procedure. Ultrasound guidance is recommended for improved accuracy and safety during laryngeal EMG.