Computational fluid dynamics simulation of the upper airway of obstructive sleep apnea syndrome by Muller maneuver

Introduction Obstructive sleep apnea syndrome (OSAS) is a sleep disorder caused by an excessive narrowing of the pharyngeal airway that also collapses during inspiration, with an important role played by the lateral pharyngeal wall in the development of the obstruction. Objective To describe our surgical experience with modified expansion sphincter pharyngoplasty (MESP) in the management of lateral collapse in upper airway multilevel surgery. Methods A total of 20 patients with moderate to severe OSAS were recruited in the Ear, Nose and Throat (ENT) Department of the University of Palermo, Italy. All of the enrolled patients refused the ventilatory therapy. The subjects were evaluated for snoring, and daytime sleepiness had a clinical evaluation including collection of anthropometric data and ENT examination and rhinofibroscopy with Müller maneuver. The patients undergoing upper airway multilevel surgery and we selected for MESP the patients with an oropharyngeal transverse pattern of collapse at Müller maneuver. Results In the postoperative assessment, all of the patients reported a reduction in snoring scores and daytime sleepiness. We observed a reduction in the mean apnea-hypopnea index (AHI) of 57.5% of the sample, which decreased from a mean value of 41.7 ( ± 21.5) to 17.4 ( ± 8.9) (p < 0.05), with a success rate, according to the Sher criteria, of 65%. We observed very few postoperative complications. Conclusion Modified expansion sphincter pharyngoplasty in multilevel surgical therapy preceded by a careful selection of patients has proven to be effective in treating patients with moderate to severe syndromes.

Download Full-text

Computational fluid dynamics endpoints to characterize obstructive sleep apnea syndrome in children

Journal of Applied Physiology ◽

10.1152/japplphysiol.00746.2013 ◽

2014 ◽

Vol 116 (1) ◽

pp. 104-112 ◽

Cited By ~ 38

Author(s):

David M. Wootton ◽

Haiyan Luo ◽

Steven C. Persak ◽

Sanghun Sin ◽

Joseph M. McDonough ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Obstructive Sleep Apnea Syndrome ◽

Sleep Apnea Syndrome ◽

Nasal Resistance ◽

Cfd Model ◽

Obstructive Sleep ◽

Apnea Syndrome

Computational fluid dynamics (CFD) analysis may quantify the severity of anatomical airway restriction in obstructive sleep apnea syndrome (OSAS) better than anatomical measurements alone. However, optimal CFD model endpoints to characterize or assess OSAS have not been determined. To model upper airway fluid dynamics using CFD and investigate the strength of correlation between various CFD endpoints, anatomical endpoints, and OSAS severity, in obese children with OSAS and controls. CFD models derived from magnetic resonance images were solved at subject-specific peak tidal inspiratory flow; pressure at the choanae was set by nasal resistance. Model endpoints included airway wall minimum pressure (Pmin), flow resistance in the pharynx (Rpharynx), and pressure drop from choanae to a minimum cross section where tonsils and adenoids constrict the pharynx ( dP TAmax). Significance of endpoints was analyzed using paired comparisons ( t-test or Wilcoxon signed rank test) and Spearman correlation. Fifteen subject pairs were analyzed. Rpharynx and dP TAmax were higher in OSAS than control and most significantly correlated to obstructive apnea-hypopnea index (oAHI), r = 0.48 and r = 0.49, respectively ( P < 0.01). Airway minimum cross-sectional correlation to oAHI was weaker ( r = −0.39); Pmin was not significantly correlated. CFD model endpoints based on pressure drops in the pharynx were more closely associated with the presence and severity of OSAS than pressures including nasal resistance, or anatomical endpoints. This study supports the usefulness of CFD to characterize anatomical restriction of the pharynx and as an additional tool to evaluate subjects with OSAS.

Download Full-text