The influence of surgical hyoid bone repositioning on upper airway collapsibility

Abstract

<b>Introduction:</b> 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. <b>Methods:</b> 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. <b>Results:</b> 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&gt;0.39). However, hyoid repositioning in anterior, anterior-cranial and anterior-caudal directions significantly decreased ΔPclose (p&lt;0.005). Anterior hyoid repositioning decreased ΔPclose progressively with each increment (p&lt;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. <b>Conclusion:</b> 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 OSA