Simulation studies of the role of esophageal mucosa in bolus transport

Abstract

Based on a fully coupled computational model for esophageal transport, we analyzed the role of the mucosa (including the submucosa) in esophageal bolus transport and how bolus transport is affected by mucosal stiffness. Two groups of studies were conducted using a computational model. In the first group, a base case that represents normal esophageal transport and two hypothetical cases were simulated: 1) esophageal mucosa replaced by muscle and 2) esophagus without mucosa. For the base case, the geometric configuration of the esophageal wall was examined and the mechanical role of mucosa was analyzed. For the hypothetical cases, the pressure field and transport features were examined. In the second group of studies, cases with mucosa of varying stiffness were simulated. Overall transport characteristics were examined and both pressure and geometry were analyzed. Results show that a compliant mucosa helped accommodate the incoming bolus and lubricate the moving bolus. Bolus transport was marginally achieved without mucosa or with mucosa replaced by muscle. A stiff mucosa greatly impaired bolus transport due to lowered esophageal distensibility and increased luminal pressure. We conclude that mucosa is essential for normal esophageal transport function. Mechanically stiffened mucosa reduces the distensibility of the esophagus by obstructing luminal opening and bolus transport. Mucosal stiffening may be relevant in diseases characterized by reduced esophageal distensibility, elevated intra-bolus pressure, and/or hypertensive muscle contraction such as eosinophilic esophagitis and jackhammer esophagus.

Intrabolus Pressure Has Better Correlation Than Eosinophilia with Dysphagia Severity in Fibrostenotic Eosinophilic Esophagitis: A Pilot Study

“…As shown by Nguyen et al in 42 patients with non-obstructive dysphagia, IBP and IBP slope were significantly higher in non-obstructive dysphagia patients than in healthy controls regardless of the presence of non-specific motility patterns [14]. In another study by Kou et al, the importance of IBP was highlighted in a computational model of esophageal transport [15]. In this study, mucosal stiffness was associated with a rise in IBP and a decrease in bolus transit efficiency.…”

A review of the approaches to predict the ease of swallowing and post-swallow residues

“…Results for different activation pattern of the longitudinal and circumferential muscles show that coordination between lumen closure and esophageal shortening has an important effect on the intra-bolus pressure pattern. The role of mucosa stiffness in bolus transport was also highlighted in a 990 following study by the same authors who, based on their simulations, speculate that a stiffened mucosa might lead to significantly back bolus transport (Kou et al, 2017).…”

“…The glottis separates the pharynx from the tracheal cartilages and supports the vocal folds. The pharynx extends for a resting length of 12 to 85 14 cm and contracts, following the laryngeal elevation, to shorten the distance that the bolus has to travel during swallowing (Kou et al, 2017). Directly above the glottis sits a cartilaginous leaf-shaped structure, the epiglottis, that bends down in normal swallowing in order to guide the bolus downward to the esophagus.…”

An Overview of Computational Fluid Structure Interaction: Methods and Applications

“…An adaptive mesh technique may prevent this issue and keep computational cost in check. Kou et al [44] validated their numerical pressure contours with clinical manometry measurements.…”