Does Medialization Improve Swallowing Function in Patients with Unilateral Vocal Fold Paralysis? A Systematic Review

Glottal incompetence caused by unilateral vocal fold paralysis (UVFP) is a common cause of dysphagia and aspiration. Treatments targeted at reducing glottal incompetence by injection augmentation or medialization thyroplasty are well established at improving voice outcomes, but improvements in swallowing function are less clear. The objective of this systematic review was to determine the impact of vocal fold medialization on dysphagia outcomes. Six electronic bibliographic databases and one clinical trial registry were searched on 3/13/2020. Our patient population were adult patients with verified UVFP that underwent vocal fold medialization. We limited review to prospective studies that had formal dysphagia assessment both before and after medialization. Nine studies met selection criteria (7 prospective case series and 2 prospective cohort studies) totaling 157 patients. The most common etiology of UVFP was iatrogenic (74/157; 47%). The majority of patients underwent injection augmentation (92/157; 59%), and the remaining underwent medialization thyroplasty. A variety of methods were used to assess changes in dysphagia including patient-reported outcome measures, flexible endoscopic evaluation of swallowing, videofluoroscopic swallow study, and high-resolution manometry. 7/9 studies demonstrated clinically significant improvement in swallowing function following medialization; 4/9 studies demonstrated statistically significant improvement, and three studies did not show statistically significant improvement after intervention. Study participants and outcome measures evaluating swallowing function in this review were heterogeneous. Moreover, the reviewed studies are concerning for multiple risks of bias impacting their conclusions. Taken together, this systematic review demonstrates limited evidence that injection augmentation and medialization thyroplasty improve swallowing function and/or safety.