RT Journal Article SR Electronic T1 The influence of surgical hyoid bone repositioning on upper airway collapsibility JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA755 DO 10.1183/13993003.congress-2021.PA755 VO 58 IS suppl 65 A1 Corine Samaha A1 Hiba Tannous A1 Diane Salman A1 Joseph Ghafari A1 Jason Amatoury YR 2021 UL http://erj.ersjournals.com/content/58/suppl_65/PA755.abstract AB Introduction: Surgical hyoid repositioning procedures are a treatment option for obstructive sleep apnea (OSA), however patient outcomes are highly variable. The role of hyoid position in maintaining upper airway (UA) patency is poorly understood and may underly treatment efficacy. Thus, the aim of this study was to determine the effect of hyoid repositioning on UA collapsibility in an animal model.Methods: We studied 7 supine, anaesthetized, adult, male, spontaneously breathing New Zealand White rabbits with a passive UA (isolated via tracheostomy). The hyoid was surgically repositioned within the mid-sagittal plane along cranial, caudal, anterior, anterior-cranial (45°) and anterior-caudal (45°) directions in 1mm increments from baseline (0mm) to 5mm. At each hyoid position (direction/increment), UA collapsibility was quantified using Pclose, the negative pressure required to close the UA.Results: Baseline Pclose for the group was -3.55 ± 0.95 (mean±SD) cmH2O. Overall, hyoid repositioning in cranial and caudal directions had no significant effect on ΔPclose (change in Pclose from baseline; p>0.39). However, hyoid repositioning in anterior, anterior-cranial and anterior-caudal directions significantly decreased ΔPclose (p<0.005). Anterior hyoid repositioning decreased ΔPclose progressively with each increment (p<0.02), where at 5mm ΔPclose was -3.98 ± 1.31 cmH2O. Similar incremental decreases in ΔPclose were achieved in both anterior-cranial and anterior-caudal directions.Conclusion: Changes in UA patency following hyoid repositioning are direction and magnitude dependent. This may have implications for guiding and improving the outcomes of surgical hyoid bone interventions for the treatment of OSAFootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA755.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).