The Effect of an Increasing Subglottal Stenosis Constriction That Extends From the Vocal Folds to the Inferior Border of the Cricoid Cartilage.

Acquired subglottal stenosis is an unpredicted complication that can occur in some patients who have undergone prolonged endotracheal intubation. It is a narrowing of the airway at the level of the cricoid cartilage that can restrict airflow and cause breathing difficulty. Stenosis is typically treated with endoscopic airway dilation, with some patients experiencing multiple recurrences. The study highlights the potential of computational fluid dynamics as a noninvasive method for monitoring subglottic stenosis, which can aid in early diagnosis and surgical planning. An anatomically accurate human laryngeal airway model was constructed from computerized tomography (CT) scans. The subglottis cross-sectional area was narrowed systematically using ≈10% decrements. A quadratic profile was used to interpolate the transformation of the airway geometry from its modified shape to the baseline geometry. The numerical results were validated by static pressure measurements conducted in a physical model. The results show that airway resistance follows a squared ratio that is inversely proportional to the size of the subglottal opening (R∝A-2). The study found that critical constriction occurs in the subglottal region at 70% stenosis (upper end of grade 2). Moreover, removing airway tissue below 40% stenosis during surgical intervention does not significantly decrease airway resistance.

Acoustic Screening of the "Wet voice": Proof of Concept in an ex vivo Canine Laryngeal Model.

BACKGROUND: Current protocols for bedside swallow evaluation have high rates of false negative results. Though experts are not consistently able to screen for aspiration risk by assessing vocal quality, there is emerging evidence that vocal acoustic parameters are significantly different in patients at risk of aspiration. Herein, we aimed to determine whether the presence of material on the vocal folds in an excised canine laryngeal model may have an impact on acoustic and aerodynamic measures. METHODS: Two ex vivo canine larynges were tested. Three liquids of different viscosities (1:100 diluted glycerin, pure glycerin, and honey-thick Varibar) were placed on the vocal folds at a constant volume. Acoustic and aerodynamic measures were obtained in both adducted and abducted vocal fold configurations. Intraglottal high-speed imaging was used to approximate the maximum divergence angle of the larynges in the studied conditions and examine its relationship to vocal efficiency (VE) and acoustic measures. RESULTS: In glottic insufficiency conditions only, we found that several acoustic parameters could predict the presence of material on the vocal folds. Based on the combination of the aerodynamic and acoustic data, we found that decreased spectral energy in the higher harmonics was associated with decreased VE in the presence of material on the vocal folds and/or glottic insufficiency. CONCLUSION: Decreased spectral energy in the higher harmonics of the voice was found to be a potential biomarker of swallowing dysfunction, as it correlates with decreased vocal efficiency due to material on the vocal folds and/or glottic insufficiency, both of which are known risk factors for aspiration. LEVEL OF EVIDENCE: NA Laryngoscope, 133:2517-2524, 2023.

Endoscopic posterior cricoid reduction: A surgical method to improve posterior glottic diastasis.

OBJECTIVES/HYPOTHESIS: Describe the preoperative evaluation of patients with glottic diastasis who are candidates for endoscopic posterior cricoid reduction (EPCR) and their perioperative and postoperative surgical and voice outcomes, and validate the aerodynamic benefit of EPCR using computation fluid dynamics (CFD)-based modeling from computed tomography (CT) scans. STUDY DESIGN: Retrospective case series. METHODS: Thirteen patients who underwent EPCR were followed from 2013 to 2017. They received a preoperative voice evaluation, microlaryngoscopy and bronchoscopy, dynamic voice CT (performed on patients seen from 2014 to study completion), and postoperative voice evaluation (n = 12). Postoperative inpatient days, complications, and postoperative endoscopic intervention were collected. To validate the aerodynamic benefit of EPCR, CFD modeling was carried out on one patient. RESULTS: Thirteen patients (nine females, nine with intubation injury, and four with post-airway reconstruction dysphonia) underwent EPCR at a mean age of 11.0 years. The mean preoperative and postoperative Pediatric Voice handicap Index scores were 53.8 and 33.8, respectively (P = .006). Mean maximum phonation time preoperatively and postoperatively was 5.3 and 6.7, respectively (P = .04). Of eight patients who underwent preoperative CT imaging, all demonstrated a posterior gap. Modeling demonstrated a change in flow and pressure. The mean hospital stay was 2.4 days. Nine patients underwent postoperative endoscopic intervention, and one experienced a complication that resolved with intervention. CONCLUSIONS: Patients who underwent EPCR for dysphonia following intubation or airway reconstruction showed improvements in vocal efficiency, loudness, and perceived voice handicapping. Their hospital stay was brief, with few complications. CFD modeling corroborated these clinical findings. EPCR thus warrants consideration in the management of patients with posterior glottic diastasis. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:S1-S9, 2019.