title: Impact of stepwise mandibular advancement on upper airway mechanics in obstructive sleep apnea using phrenic nerve magnetic stimulation.
abstract: Mandibular advancement devices (MAD) represent a potential treatment for obstructive sleep apnea (OSA). However, their mechanisms of actions are not completely understood. This study was aimed to explore the effects of MAD-induced mandibular protrusion on upper airway mechanics. 25 men commencing treatment for OSA with MAD were recruited. Phrenic nerve magnetic stimulation (PNMS) was used to measure flow/pressure relationship during progressive protrusion in three conditions (without MAD, MAD at minimum protrusion, and MAD at maximum tolerable protrusion). Pressures were recorded simultaneously at three different upper airway segments (naso-, velo-, and oro-pharynx). Without MAD, PNMS twitches induced flow-limitation at the velopharyngeal level in 19 subjects and six of them experienced a shift in the flow-limitation site to the lower segment with MAD at maximum protrusion. An association was found between having a velopharyngeal limitation site without MAD and the increase in maximum flow with the advanced MAD. These data suggest that mandibular advancement devices are acting predominantly at the velopharyngeal level.
authors.affiliation: Unité de recherche en pneumologie, Centre de recherche, Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Gakwaya
authors.forename: César Augusto
authors.initials: CA
authors.lastname: Melo-Silva
authors.forename: Jean-Christian
authors.initials: JC
authors.lastname: Borel
authors.forename: Eric
authors.initials: E
authors.lastname: Rousseau
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Masse
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sériès
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D006801:Humans; D008176:Lung Volume Measurements; D055909:Magnetic Field Therapy / Q000379:methods*; D008297:Male; D019186:Mandibular Advancement; D008875:Middle Aged; D010791:Phrenic Nerve / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome
keywords: Magnetic stimulation; Mandibular advancement device; Obstructive sleep apnea; Upper airway physiology