JAP-00560-2005.R1 Title: Mandibular advancement decreases pressures in the tissues surrounding the upper airway in rabbits.

The pharyngeal airway can be considered as an airway luminal shape formed by surrounding tissues, contained within a bony enclosure formed by the mandible, skull base and cervical vertebrae. Mandibular advancement (MA), a therapy for obstructive sleep apnea, is thought to increase the size of this bony enclosure, and decrease the pressure in the upper airway extra-luminal tissue space (ETP). We examined the effect of MA on upper airway airflow resistance (RUA) and ETP in a rabbit model. Methods: We studied 11 male, supine, anaesthetised, spontaneously breathing, NZ white rabbits in which ETP was measured via pressure transducer tipped catheters inserted into the tissues surrounding the lateral (ETPlat) and anterior (ETPant) pharyngeal wall. Airflow ( ˙ V), measured via surgically inserted pneumotachograph in series with the trachea. and tracheal pressure (PTR) were recorded while graded MA at 75º and 100º to the horizontal was performed using an external traction device. Data were analysed using a linear mixed effects statistical model. Results: MA at 100º increased mouth opening from 4.7 ± 0.4 t