Biomechanics and Modeling in Mechanobiology

, Volume 17, Issue 4, pp 1069–1082 | Cite as

Studies of abnormalities of the lower esophageal sphincter during esophageal emptying based on a fully coupled bolus–esophageal–gastric model

  • Wenjun Kou
  • John E. Pandolfino
  • Peter J. Kahrilas
  • Neelesh A. Patankar
Original Paper


The aim of this work was to develop a fully coupled bolus–esophageal–gastric model based on the immersed boundary–finite element method to study the process of esophageal emptying across the esophagogastric junction (EGJ). The model included an esophageal segment, an ellipsoid-shaped stomach, a bolus, and a simple model of the passive and active sphincteric functions of the lower esophageal sphincter (LES). We conducted three sets of case studies: (1) the effect of a non-relaxing LES; (2) the influence of the tissue anisotropy in the form of asymmetrical right- and left-sided compliance of the LES segment; and (3) the influence of LES and gastric wall stiffness on bulge formation of the distal esophageal wall. We found that a non-relaxing LES caused sustained high wall stress along the LES segment and obstruction of bolus emptying. From the simulations of tissue anisotropy, we found that the weaker side (i.e., more compliant) of the LES segment sustained greater deformation, greater wall shear stress, and a greater high-pressure load during bolus transit. In the third set of studies, we found that a right-sided bulge in the esophageal wall tends to develop during esophageal emptying when LES stiffness was decreased or gastric wall stiffness was increased. Hence, the bulge may be partly due to the asymmetric configuration of the gastric wall with respect to the esophageal tube. Together, the observations from these simulations provide insight into the genesis of epiphrenic diverticula, a complication observed with esophageal motility disorders. Future work, with additional layers of complexity to the model, will delve into the mechanics of gastroesophageal reflux and the effects of hiatus hernia on EGJ function.


Immersed boundary method Esophageal diverticulum Esophageal–gastric junction Lower esophageal sphincter stiffness 


Compliance with ethical standards

Conflicts of Interest

John E. Pandolfino discloses consulting and educational association with Medtronic, Sandhill Scientific and Ironwood Pharmaceuticals, and stock options with Crospon. Wenjun Kou, Peter J. Kahrilas, and Neelesh A. Patankar declare that they have no conflict of interest.


This work was supported by Public Health Service grants DK079902 (to J.E.P.) and DK056033 (to P.J.K).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Wenjun Kou
    • 1
  • John E. Pandolfino
    • 1
  • Peter J. Kahrilas
    • 1
  • Neelesh A. Patankar
    • 2
  1. 1.Department of Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoUSA
  2. 2.Department of Mechanical EngineeringNorthwestern UniversityEvanstonUSA

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