xRead - Swallowing Disorders in the Adult Patient (October 2024)

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S. I. Dhar et al.: Does Medialization Improve Swallowing Function in Patients

Introduction Glottal incompetence as a result of unilateral vocal fold paralysis (UVFP) is a common cause of dysphagia and as many as two-thirds of patients suffering from UVFP will have dysphagia, with one-third to one-half of patients with UVFP showing evidence of aspiration [1]. UVFP can occur from a variety of etiologies including iatrogenic high vagal or recurrent laryngeal nerve (RLN) injury, stroke, neopla sia, cervical neck or intubation trauma, radiation treatment, chemotherapy side effect, or idiopathic causes [2]. The natu ral course of UVFP varies based on the etiology with iat rogenic UVFP patients having in general a great chance of recovery compared to those patients with idiopathic causes [3, 4]. The mechanism by which UVFP results in dysphagia is complex and multifactorial, and may include issues beyond glottal incompetence, such as delay of swallowing initiation, prolonged pharyngeal transit time, weakness of the phar yngeal musculature, reduced laryngopharyngeal sensation, and subsequent reduction in the laryngeal adductor reflex responsible for swallowing safety [2]. Treatment of UVFP, regardless of technique, focuses on reducing glottic insufficiency through various means such as injection augmentation, medialization thyroplasty, arytenoid adduction, and RLN reinnervation [1]. In adults, injection augmentation and medialization thyroplasty are the most commonly utilized and accepted approaches in treat ing UVFP [6]. Although the effect of these techniques on positive voice outcomes has been well studied, there is less consensus regarding their efficacy in improving swallowing parameters [7, 8]. The goal of this systematic review was to collect and ana lyze prospective evidence to determine whether vocal fold medialization procedures, such as injection augmentation or medialization thyroplasty, improve quantitative measures of swallowing function in adults with UVFP. Methods We conducted a systematic review and reported it in accord ance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [9]. Prior to initiation of the review process, we established a writ ten protocol for study inclusion, data extraction, and risk of bias assessment. The protocol was registered on 06/13/2020 with the Open Science Framework (https://d​ oi.o​ rg/1​ 0.1​ 7605/​ OSF.​IO/​567WF).

Inclusion Criteria

Included studies evaluated adult humans (18 years or older) who underwent vocal fold medialization for verified UVFP and who had a pre- and post-intervention dysphagia assess ment. Swallowing was evaluated using various instrumental assessments (e.g., flexible endoscopic evaluation of swal lowing [FEES] or videofluoroscopic swallow study [VFSS]) and patient- or clinician-reported outcomes. Swallowing evaluations had to occur within 6 months pre-intervention and 12 months post-intervention. There were no exclusions based on language. In addition, we chose to limit our identification of eligible research to prospective studies because they are better able to control for the collection of outcomes data specific to this exposure. That is, these study methods allow for greater completion of the data collected and improved control of the temporal association between vocal fold medialization (exposure) and the potential consequences of this treatment (outcomes) [10–12]. Exclusion criteria included (1) retrospective study design, editorials, viewpoints, letters to the editor, cases series with ≤ 3 patients, and reviews, (2) patients <18 years old, (3) patients with bilateral vocal fold paralysis or vocal fold paresis, (4) patients with prior treatment for UVFP such as injection augmentation, thyroplasty +/- arytenoid adduction before study enrollment, (5) patients with pre-existing dys phagia due to etiologies other than UVFP, (6) patients with esophageal disease other than reflux, and (7) patients with central nervous system disease, connective tissue disorders, head and neck tumors (other than thyroid), and history of radiation or surgery to the oral cavity or pharynx. A medical librarian with expertise in systematic review methods and searching (C.P.) developed and executed the search after consulting with the research team. The search was developed based on key articles selected by the team. Prior to running the searches in each database, the search was peer-reviewed by a second medical librarian. The search was completed in PubMed through NCBI, Embase through Elsevier, the Cochrane Library on the Wiley Platform, CINAHL Plus through EBSCO, the Web of Science Core Collection, and Scopus through Elsevier, ProQuest Dis sertations and Theses Global database, and Open Access Thesis Dissertations as part of the gray literature from data base inception to 03/13/2020. An update was completed on Exclusion Criteria Literature Search

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