3D patient-specific numerical modeling of the soft palate considering adhesion from the tongue

Abstract

Collapse of the soft palate in the upper airway contributes to obstructive sleeping apnea (OSA). In this study, we investigate the influence of the adhesion from the tongue on the soft palate global response. This is achieved using a cohesive zone finite element approach. A traction-separation law is determined to describe the adhesion effect from the surface tension of the lining liquid between the soft palate and the tongue. According to pull-off experimental tests of human lining liquid from the oral surface of the soft palate, the corresponding cohesive properties, including the critical normal traction stress and the failure separation displacement, are obtained. The 3D patient-specific soft palate geometry is accounted for, based on one specific patient's computed tomography (CT) images. The calculation results show that influence of the adhesion from the tongue surface on the global response of the soft palate depends on the length ratio between the cohesive length and the soft palate length. When the length of the cohesive zone is smaller than half of the soft palate length, the adhesion's influence is negligible. When the adhesion length is larger than 70 percent of soft palate length, the adhesion force contributes to preventing the soft palate from collapsing towards to the pharynx wall, i.e. the closing pressure is more negative than in the no adhesion case. These results may provide useful information to the clinical treatment of OSA patients.

Computational Biomechanics of Sleep: A Systematic Mapping Review

“…The first focused on the microgravity [ 41 ], while the second one targeted on Down syndrome [ 42 ]. A Google Scholar search for grey literature yielded four results, totaling 27 studies conclusive for qualitative synthesis in this review [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ].…”

“…They compared models with passive muscles, OSA models, and non-OSA models with active muscles driven by different activation stress settings. In addition to the deformation and displacement of the soft tissue, closing pressure is one of the parameters of interest, which is defined by the critical negative pressure that causes the soft palate to contact the pharynx wall [ 58 , 59 ].…”

“…On the other hand, Liu et al [ 58 ] were interested in the surface tension of the mucosal lining between the soft palate and tongue. They segmented and connected the soft palate and tongue with cohesive elements.…”

“… Sankey diagram mapping the categories and basic settings of the included studies [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. FE, finite element; FSI, fluid–structure interaction; OSA, obstructive sleep apnea.…”

“… Evidence maps on modeling and features for included studies related to obstructive sleep apnea (OSA) [ 43 , 44 , 45 , 46 , 47 , 48 , 52 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 65 , 68 ]. …”