Isolated Paresis of Laryngeal Adduction: What Are the Laryngoscopic and Stroboscopic Findings?

The Poor Validity of Asymmetric Laryngoscopic Findings in Predicting Laterality in Vocal Fold Paresis

OBJECTIVE

To determine the laryngoscopic findings most predictive of laterality in vocal fold paresis in patients with known RLN and/or SLN paresis by laryngeal electromyography (LEMG).

STUDY DESIGN

Blinded, prospective video perceptual analysis study.

METHODS

Patients with vocal fold paresis diagnosed by LEMG at a tertiary care hospital from 2017 to 2019 were identified. Two fellowship-trained laryngologists blinded to clinical history and LEMG results reviewed laryngostroboscopic examinations and assessed for evidence of paresis using defined criteria. Inclusion criteria were adults with laryngeal asymmetry and evidence of decreased recruitment on LEMG. Exclusion criteria were children, presence of laryngeal lesions, myasthenia gravis, vocal fold paralysis, and normal laryngeal symmetry.

RESULTS

We identified 95 patients who were diagnosed with vocal fold paresis with LEMG who met inclusion and exclusion criteria (mean age 43.8 ± 20.4 years (18-88), 38.9% male). When comparing the laterality of the observed laryngoscopic finding with LEMG, we found that in patients who had severe true vocal fold (TVF) range of motion disturbance, the laterality of the finding matched the LEMG distribution of paresis in 12 out of 13 (92.3%) patients (P = 0.002). No other laryngoscopic findings reliably predicted laterality including corniculate and cuneiform cartilage asymmetry, pyriform sinus dilation, abnormal TVF show, petiole deviation, abnormal ventricular show, increased supraglottic area, and FVF hyperfunction of the opposite side.

CONCLUSION

With the exception of severe TVF range of motion disturbance, there seems to be poor validity of laryngoscopic findings in predicting the affected side in vocal fold paresis. We recommend neurophysiologic testing to confirm the clinical diagnosis of vocal fold paresis.

Volumetric measures of the paralyzed vocal fold using computerized tomography; its clinical implication

OBJECTIVE

To report the volumetric measures of the paralyzed vocal fold in patients undergoing injection laryngoplasty.

MATERIAL AND METHOD

All the medical records of patients with unilateral vocal fold paralysis who had high resolution computerized tomography scan of the neck and chest prior to injection laryngoplasty between October 2015 and May 2018 were included. Volumetric evaluation of the vocal folds was performed by measuring the vocal fold height using coronal images and the vocal fold length and width using axial images.

RESULTS

A total of 21 patients divided into 13 males and 8 females were identified. The mean age was 56.66 ± 20.94 years. The mean volume of the paralyzed vocal fold was significantly smaller than that of the non-paralyzed vocal fold (p < .05). Similarly, the mean length and height of the paralyzed vocal folds were smaller than those of the non-paralyzed vocal folds (p < .05).

CONCLUSION

Volumetric measurements of the paralyzed vocal fold in comparison to the normal vocal fold in a group of 21 patients with unilateral vocal fold paralysis shows the presence of significant difference between the normal and affected site, and the presence of large inter-subject variation. Information on the volume difference between the two vocal folds may be used to better estimate the amount that needs to be injected in medialization procedures.