Author(s)
R. Jun Lin, MD
Michael Belsky, MD
Bandon Smith, MD
Elysia Grose, MD
Rosane Nisenbaum, PhD
Clark A. Rosen, MD
Michael C. Munin, MD
Libby J. Smith, DO
Affiliation(s)
Unity Health- Toronto; Stanford Univ. School of Medicine; Univ. of Pittsburgh Medical Center; Univ of Toronto; Univ. of California - San Francisco;
Abstract:
Background/Objective: LEMG is a useful diagnostic test in the evaluation of vocal fold paralysis (VFP). This study investigates factors that can make LEMG challenging to perform.
Methods: Patients with subacute unilateral VFP presented for LEMG were prospectively enrolled. Demographic data including BMI, previous neck surgery, and anatomic factors were collected. Patient-reported pain related to the procedure was recorded on a visual analogue scale (VAS). Electromyographer and otolaryngologist recorded a consensus rating of the perceived difficulty in performing the test.
Results: 111 patients (56.8% female) were enrolled between Aug 2015 and Aug 2018. Mean age was 55±14 years and average body mass index (BMI) was 28.5±6.4. Mean VAS score was 3.5±2.4. 41.0% of the tests were considered “very easy” and 40.0% were considered “mildly challenging” by the clinicians. 15.7% and 2.8% were considered “moderately challenging” and “extremely challenging”, respectively. Of all patients, most common factors making LEMG difficult to perform include patient intolerance (15.6%) and difficult surface anatomy (50.5%). Surprisingly, elevated BMI is associated with a lower VAS score (Spearman Correlation Coefficient=-0.20, p=0.04). Bivariate analyses showed that prior neck surgery is associated with elevated VAS (p=0.02) but clinician perceived difficulty of performing the test is not associated with elevated VAS scores (p=0.55).
Conclusions: Majority of the LEMG tests are well tolerated by patients. Patient intolerance and difficult surface anatomy make LEMG challenging to perform, which affects clinician confidence in the test results, but does not increase pain in patients undergoing the test.