Constructing a patient‐specific computer model of the upper airway in sleep apnea patients

Abstract

Objective: The use of computer simulation to develop a high-fidelity model has been proposed as a novel and costeffective alternative to help guide therapeutic intervention in sleep apnea surgery. We describe a computer model based on patient-specific anatomy of obstructive sleep apnea (OSA) subjects wherein the percentage and sites of upper airway collapse are compared to findings on drug-induced sleep endoscopy (DISE).Study Design: Basic science computer model generation.Methods: Three-dimensional finite element techniques were undertaken for model development in a pilot study of four OSA patients. Magnetic resonance imaging was used to capture patient anatomy and software employed to outline critical anatomical structures. A finite-element mesh was applied to the volume enclosed by each structure. Linear and hyperelastic soft-tissue properties for various subsites (tonsils, uvula, soft palate, and tongue base) were derived using an inverse finiteelement technique from surgical specimens. Each model underwent computer simulation to determine the degree of displacement on various structures within the upper airway, and these findings were compared to DISE exams performed on the four study patients.Results: Computer simulation predictions for percentage of airway collapse and site of maximal collapse show agreement with observed results seen on endoscopic visualization.Conclusion: Modeling the upper airway in OSA patients is feasible and holds promise in aiding patient-specific surgical treatment.

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 ].…”

“…Ilegbusi et al [ 56 ] discovered that a supine position without dilator muscle activation decreased airway cross-sectional width at the tongue, epiglottis, and larynx levels. Dhaliwal et al [ 52 ] reported that different patients had different sites of maximal collapse, including the soft palate, tongue base, and oropharynx. Moreover, the cross-sectional area of the airway was often illustrated with the displacement and deformation of the soft palate.…”

“…As given in Table 5 , OSA was presumed by initiating an apnea breathing condition and compared to eupnea (i.e., normal breathing) by adjusting the boundary inlet air pressure [ 48 , 54 ], or by “paralyzing” the tongue (dilator) muscle [ 52 , 56 , 60 , 65 ]. The former could be accomplished by measuring pressure in vivo using a pressure transducer [ 48 ].…”

“…The former could be accomplished by measuring pressure in vivo using a pressure transducer [ 48 ]. Specific techniques were presented to “paralyze” the tongue, i.e., to compare activation and inactivation of the dilator muscle, where collapsibility was defined by the changes in result between activation and inactivation [ 52 ]. Ilegbusi et al [ 56 ] applied a force–time activation function for the genioglossus, in which the magnitude of the force was determined by matching the profile of the airway opening at the epiglottis level observed in trials of neurostimulation.…”

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

“…This study describes a computer model based on patient-specific anatomy in those with OSA wherein the percentage and sites of UA collapse are compared with findings with DISE. 309 Three-dimensional finite element techniques were undertaken for model development in a pilot study of 4 individuals with OSA. Magnetic resonance imaging was used to capture images of patients' anatomy, and a software program was used to outline critical anatomical structures.…”