Imaging Modalities in the Etiologic Evaluation of Unilateral Vocal Fold Paralysis

Imaging Modalities for Identifying Causes of Vocal Fold Paralysis: A Systematic Review and Meta-Analysis

BACKGROUND

Vocal fold paralysis (VFP), involving one or both vocal folds, often indicates underlying pathologies. Identifying VFP causes is vital for excluding malignancies and focusing on treating the cause. While various imaging methods are used to investigate VFP causes, their detection abilities remain unclear. This study aims to assess the detection prevalence of different imaging techniques in determining the causes of VFP.

METHODS

In September 2023 a comprehensive search was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines across multiple databases, including Web of Science, PubMed, Scopus, Cochrane CENTRAL, and EMBASE. Following the search, the retrieved studies were screened based on the predefined eligibility criteria. Data extraction from the included studies was carried out independently by two authors. Outcomes were analyzed using pooled proportions and 95% confidence intervals.

RESULTS

Our meta-analysis encompassed 14 studies with 1492 VFP patients included. Malignant causes for VFP identification were most prevalent in F-fluorodeoxyglucose Positron Emission Tomography (PET)/Computed Tomography (CT) (41.5%) followed by Magnetic resonance imaging (MRI) (40%), with CT being the lowest (17.1%). Conversely, benign causes had the highest prevalence in F-fluorodeoxyglucose PET/CT (10.8%), followed by MRI (6.7%) and CT (4%). In the VFP cause identification, MRI had the highest detection prevalence (58.1%), followed by CT (30.1%), and Ultra Sound (US) had the lowest (26.8%). In chest lesion detection, CT had the highest prevalence (17.6%), followed by Chest X-ray (CXR) (6.5%). Head lesions were detected with CT at a prevalence of 15%, while neck lesion detection showed CT prevalence at 38.9% and US at 20.6%.

CONCLUSION

Our study revealed varying prevalence rates for the identification of malignant and benign causes across different imaging modalities. MRI demonstrated the highest overall detection prevalence for VFP causes, while CT was most commonly used and had the highest prevalence for specific lesions detection in various regions. These findings provide valuable insights into the diagnostic utility of different imaging techniques in the evaluation of VFP.

Immediate effect of recurrent laryngeal nerve stimulation in patients with idiopathic unilateral vocal fold paralysis

BACKGROUND

There is a lack of effective treatment for idiopathic unilateral vocal fold paralysis (IUVFP). A better phonation was reported by patients after laryngeal nerve stimulation during our clinical examination.

OBJECTIVES

This study aims to investigate immediate effect of recurrent laryngeal nerve (RLN) stimulation on phonation in patients with IUVFP.

MATERIAL AND METHODS

Sixty-two patients with clinically identified IUVFP underwent RLN stimulation with needle electrodes. Laryngoscopy, acoustic analysis, and voice perception assessment were performed for quantitative comparison of vocal function and voice quality before and after the intervention.

RESULTS

Laryngoscopic images showed a larger motion range of the paralyzed vocal fold (p < .01) and better glottal closure (p < .01) after RLN stimulation. Acoustic analysis revealed that the dysphonia severity index increased significantly (p < .01) while the jitter and shimmer decreased after the intervention (p < .05). According to perceptual evaluation, RLN stimulation significantly increased RBH grades in patients with IUVFP (p < .01). Furthermore, the improvement in voice perception had a moderate positive correlation with the decrease in the glottal closure.

CONCLUSIONS AND SIGNIFICANCE

This study shows a short-term improvement of phonation in IUVFP patients after RLN stimulation, which provides proof-of-concept for trialing a controlled delivery of RLN stimulation and assessing durability of any observed responses.

Computed Tomography Measurements in Assessment of Idiopathic Vocal Fold Paralysis

OBJECTIVE

Our study aimed to both identify the incidence and clinical presentation of patients presenting with idiopathic vocal fold paralysis (IVFP). Secondarily we aimed to assess the radiographic findings of computed tomography (CT) studies along the course of the vagus and recurrent laryngeal nerves (RLN), specifically measuring for potential areas of compression at the skull base and mediastinum. We hypothesized that a proportion of patients diagnosed with IVFP would have significant differences in measurements when compared to age-gender matched controls on CT imaging.

STUDY DESIGN

Institutional review board approved retrospective cohort study METHODS: We assessed patients presenting to a tertiary voice care center between 2003 and 2019 with diagnosis of vocal fold paralysis. Data collected includes demographics, clinical exam findings, and CT measurements including dimensions at bilateral jugular foramen, aortopulmonary (AP) window and surrounding vascular structures. Statistical analysis was then performed using Pearson χ², and Mann Whitney U tests to determine differences variables of interest.

RESULTS

A total of 606 patients were reviewed. Of these patients 60 (9.9%) patients were determined to have IVFP. Left-sided VFP was seen more commonly in 78.3% (N = 47) of idiopathic patients. Our IVFP group had an overall higher incidence of cardiovascular disease [OR = 3.378, 95%CI 1.907-5.941, P < 0.001] compared to those with identified causes for paralysis. Specifically, IVFP patients showed a higher incidence of combined cardiovascular co-morbidities (P < 0.001), mitral valve stenosis (P = 0.007), pulmonary hypertension (P < 0.0001) and congestive heart failure (P < 0.001). When evaluating CT imaging, the AP window was mentioned in only 2 (3.3%) of our idiopathic patients CT reports. The IVFP cohort had a lower median AP window volume (P = 0.020) when compared to age-gender matched controls. This significantly smaller AP window volume was also seen when only left sided IVFP compared to both right-sided paralysis (P < 0.001) and age matched control patients (P < 0.001).

CONCLUSION

The significance of cardiovascular comorbidities combined with findings of statistically narrowed AP window may help provide an explanation of a subset of patients diagnosed with IVFP.

Increased 18F-FDG Uptake in the Posterior Region of Contralateral Vocal Folds in Beagle Dogs With Unilateral Vocal Fold Immobility Disorders

OBJECTIVE

To explore the glycolytic metabolism of contralateral vocal fold compensation by examining the glycolytic metabolism of the posterior region of vocal folds in beagles with unilateral vocal fold immobility disorders and its correlation with acoustic parameters.

STUDY DESIGN

Prospective animal study.

SETTING

Department of Voice METHODS: Ten adult beagles were divided randomly into three groups: a unilateral cricoarytenoid joint dislocation (UCAJD) group (n = 4), a unilateral vocal fold paralysis (UVFP) group (n = 4), and a control group (n = 2). Positron emission tomography-computed tomography (PET/CT) scans of larynx and recordings of vocalizations were collected 4 months after the operations. The maximum standardized uptake values (SUVmax) of 18F-FDG within each posterior region of the vocal folds were obtained from PET/CT and voice recordings were analyzed for acoustic parameters F0, jitter, shimmer, and loudness using PRAAT.

RESULTS

In both UCAJD and UVFP groups, a significant increase of SUVmax was observed in the contralateral vocal fold relative to the impaired fold (P < 0.05). The SUVmax values of the contralateral vocal folds and the SUVmax values of the impaired vocal folds in the UCAJD, UVFP, and control groups were both found to be significantly different (P < 0.05). The SUVmax of the contralateral vocal fold may exhibit a potentially negative correlation with jitter and shimmer, with R2 values of 0.42 and 0.26 and P values of 0.03 and 0.11, respectively.

CONCLUSION

UCAJD and UVFP can cause enhanced glycolytic metabolism of the contralateral vocal fold relative to the impaired vocal fold. The SUVmax of the contralateral vocal fold may be positively correlated with acoustic quality.