A Patient-Derived 3D-Printed Silicone Model for Studying Pharyngeal Collapse and Flow Limitation in Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea (OSA) is caused by dynamic collapse of the upper airway during inspiration; realistic upper airway phantoms that combine imaging and pressure-flow measurements are needed to study collapse mechanics and evaluate therapies.  The objective of this study is to fabricate and validate an additively manufactured, patient?specific silicone upper?airway phantom that reproduces reversible, reproducible pharyngeal collapse and to quantify its deformation with computer tomography (CT) imaging and its pressure-flow behavior under controlled inspiratory suction. The airway lumen was segmented from a clinical magnetic resonance imaging (MRI) dataset and converted into a two?part casting mold. A rigid outer shell and a water?soluble airway core were 3D?printed; regions corresponding to soft palate, tongue and lateral walls were cast in compliant silicone. The assembled phantom was mounted in a flow rig and measured with CT imaging in baseline, moderate flow (~5 l/min) and collapsed states. Pressure and flow were recorded in separate, identically controlled runs to derive airway resistance and identify collapse thresholds. CT showed focal, reproducible collapse at the soft palate and tongue base with minimal cross?sectional area reductions of 91 % and 97 %, respectively; flexible airway volume decreased from 8.0 cm³ (baseline) to 3.92 cm³ (collapsed), a 51.6 % reduction. Collapse produced flow limitation (flow oscillating ? 0-1 l/min) and a characteristic pressure–flow loop; the critical closing pressure immediately prior to collapse was ? ?2.4 mbar. All deformation and aerodynamic signatures were reversible and reproducible across repeats. The patient?specific silicone phantom replicates key mechanical features of a collapsible pharynx and provides a controlled, image?verified platform for mechanistic studies and preclinical testing of anatomical interventions.