HSC Section 6 Nov2016 Green Book

Reprinted by permission of Otolaryngol Head Neck Surg. 2015; 153(3):414-419.

Original Research—Laryngology and Neurolaryngology

Otolaryngology– Head and Neck Surgery 2015, Vol. 153(3) 414–419 American Academy of Otolaryngology—Head and Neck

Diagnostic Yield of Computed Tomography in the Evaluation of Idiopathic Vocal Fold Paresis

Surgery Foundation 2015 Reprints and permission:

sagepub.com/journalsPermissions.nav DOI: 10.1177/0194599815593268 http://otojournal.org

Paul M. Paddle, MD, MPH 1 , Masaany B. Mansor, MD 1 , Phillip C. Song, MD 1 , and Ramon A. Franco Jr, MD 1

Received October 26, 2014; revised May 6, 2015; accepted June 5, 2015. V ocal fold paresis implies vocal fold hypomobility due to neurologic injury, with a peripheral etiology in 90% of cases. It may result from weakness of the vagus nerve or its superior or recurrent laryngeal branches. This may occur anywhere in its course—from the lower motor neurons in the nucleus ambiguus of the medulla through the jugular foramen, neck, and mediastinum. Vocal fold paresis is unilateral in 90% of cases. 1 Paresis is the most common cause of vocal fold hypomo- bility, being present in 90% of cases. 1 Other causes of vocal fold hypomobility include myopathies (4%) and cricoaryte- noid joint dysfunction (6%). Paresis is an increasingly recognized phenomenon in patients with laryngologic com- plaints. Previous studies reported mild vocal fold hypomobi- lity in 46% of patients with vocal complaints, 71% of singing teachers with complaints of technical difficulties, and 23% of singing teachers with no vocal complaints. 1,2 Diagnosis of vocal fold paresis requires a high index of sus- picion. The symptoms of vocal fold paresis are more varied and subtle than paralysis. Classic symptoms of glottic insufficiency—such as breathy dysphonia, diplophonia, aspira- tion, and dysphagia—may be absent or muted. Instead, the patient may complain of a loss of quality volume and range, vocal instability, and increased phonatory effort. 3 Atypical symptoms, such as globus, chronic cough, and laryngospasm, are also described. Unlike the findings of an established vocal fold paralysis, such as vocal fold atrophy, bowing, and arytenoid prolapse, the examination findings of unilateral vocal fold paresis are subtle and difficult to discern from nonpathologic asymme- tries. Findings may include asymmetric vocal fold range and velocity of movement, decreased ipsilateral false vocal

No sponsorships or competing interests have been disclosed for this article.

Abstract Objective. To determine the diagnostic yield of computed tomography (CT) in establishing an etiology in patients with idiopathic unilateral vocal fold paresis (IUVFP). To determine the proportion of CT scans yielding incidental findings requiring further patient management.

Study Design. Case series with chart review.

Setting. Tertiary laryngology practice.

Subjects. Laryngology clinic patients under the care of the 2 senior authors. Methods. All clinic patients were identified who had a diag- nosis of IUVFP and underwent CT of the skull base to the upper mediastinum from 2004 to 2014. Demographic, his- torical, examination, and investigation data were extracted. CT reports and endoscopic recordings were reviewed. Patients were excluded if there were insufficient clinical find- ings recorded or if there was a known neurologic disorder, complete vocal fold immobility, or bilateral involvement. Results. A total of 174 patients with IUVFP who had also undergone contrast-enhanced CTwere identified. Of the 174 patients, 5 had a cause for their paresis identified on CT. This equated to a diagnostic yield of 2.9% (95% confidence inter- val, 0.94% to 6.6%). Of the 174 patients, 48 had other inci- dental lesions identified that required further follow-up, investigation, or treatment. This equated to an incidental yield of 27.6% (95% confidence interval, 21.1% to 34.9%). Conclusion. This is the second and largest study to evaluate the diagnostic yield of CT in the evaluation of IUVFP. It demonstrates a low diagnostic yield and a high incidental yield. These findings suggest that the routine use of CT in the evaluation of idiopathic vocal fold paresis should be given careful consideration and that a tailored approach to investi- gation with good otolaryngologic follow-up is warranted.

1 Harvard Medical School, Division of Laryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA

Corresponding Author: Paul M. Paddle, MD, Harvard Medical School, Division of Laryngology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA. Email: paulpaddle@me.com

Keywords idiopathic unilateral vocal fold paresis, computed tomogra- phy, diagnostic yield, incidental yield

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