Biomechanics of Upper Airway Collapse in Obstructive Sleep Apnea

To gain a better understanding of the biomechanics of upper airway collapse in patients with obstructive sleep apnea (OSA), the Airway Biomechanics Laboratory employs in vitro experiments in collapsible tubes (Starling Resistor) and 3D-printed upper airway replicas, fluid-structure interaction (FSI) simulations, and in vivo measurements performed during drug-induced sedated endoscopy (DISE). With the help of these tools, the Airway Lab seeks to improve our understanding of OSA pathophysiology and to develop virtual surgery planning tools to optimize surgical outcomes for patients with OSA.


Research Methodologies

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Starling Resistor Experiments

Illustration of Starling Resistor showing nasal cavity, collapsible pharynx and trachea.The Starling resistor is the paradigm biomechanical model of airway collapse in OSA. It consists of a collapsible tube (representing the pharynx) located between two rigid tubes (representing the nasal cavity and trachea).


Starling Resistor Experiment


FSI Simulations of the Starling Resistor

In the Airway Biomechanics Laboratory, FSI simulations of the Starling resistor are performed with ANSYS software. 


FSI Simulation of the Starling Resistor (view 1)


FSI Simulation of Starling Resistor (view 2)


Drug Induced Sedated Endoscopy

In collaboration with Dr. Tucker Woodson (MCW Department of Otolaryngology), our lab has performed in vivo measurements of airway collapsibility in patients with obstructive sleep apnea during drug-induced sedated endoscopy (DISE).


Drug Induced Sedated Endoscopy


3D-Printed Replica of the Human Upper Airway

The Airway Lab uses 3D-printing technology to create replicas of the human upper airway with a collapsible (silicone) pharynx.

Replica of the human upper airway with a collapsible (silicone) pharynx created with 3D printing.


The video below shows the upper airway replica being used in an experiment. Notice that when the left nostril is obstructed with a finger (increasing the upstream resistance and decreasing the pressure at the pharynx), the flexible pharynx collapses.


Airway Replica Experiment


Selected Publications

Hartfield P.J., Janczy J., Sharma A., Newsome H.A., Sparapani R.A., Rhee J.S., Woodson B.T., Garcia G.J.M. (2023) Anatomical determinants of upper airway collapsibility in obstructive sleep apnea: A systematic review and meta-analysis. Sleep Medicine Reviews 68, 101741.

Garcia G.J.M., Wolf J.J., Campbell D.A., Bailey R.S., Sparapani R.A., Welzig C.M., Woodson B.T. (2023) Mandibular advancement reduces pharyngeal collapsibility by enlarging the airway rather than affecting velopharyngeal compliance. Physiological Reports 11 (3), e15558, 1–18.

Zarandi M.A.F., Garman K., Rhee J.S., Woodson B.T., Garcia G.J.M. (2021) Effect of tube length on the buckling pressure of collapsible tubes. Computers in Biology and Medicine 136, 104693, 1–8.

Garcia G.J.M. and Woodson B.T. (2020) The collapsing anatomical structure is not always the primary site of flow limitation in obstructive sleep apnea. Journal of Clinical Sleep Medicine 16, 345–346.

Le T.B., Moghaddam M.G., Woodson B.T., Garcia G.J.M. (2019) Airflow limitation in a collapsible model of the human pharynx: Physical mechanisms studied with fluid-structure interaction simulations and experiments. Physiological Reports 7 (10), e14099, 1-16.



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