Computational Fluid Dynamic Analysis of the Posterior Airway Space After Maxillomandibular Advancement for Obstructive Sleep Apnea Syndrome

Abstract

Purpose Evaluate the soft tissue change of the upper airway after maxillomandibular advancement (MMA) by computational fluid dynamics (CFD). Materials and Methods Eight OSAS patients who required MMA were recruited into this study. All participants had pre- and post-operative computed tomography (CT) and underwent MMA by a single oral and maxillofacial surgeon. Upper airway CT data sets for these 8 participants were created with high-fidelity 3-D numerical models for computational fluid dynamics (CFD). The 3-D models were simulated and analyzed to study how changes in airway anatomy affects pressure effort required for normal breathing. Airway dimensions, skeletal changes, Apnea-Hypopnea Index (AHI), and pressure efforts of pre- and post-operative 3-D models were compared and correlations interpreted. Results After MMA, laminar and turbulent air flow was significantly decreased at every level of the airway. The cross-sectional areas at the soft palate and tongue base were significantly increased. Conclusions This study shows that MMA increases airway dimensions by the increasing the occipital base (Base) - pogonion (Pg) distance. An increase of the Base-Pg distance showed a significant correlation with an AHI improvement and a decreased pressure effort of the upper airway. Decreasing the pressure effort will decrease the breathing workload. This improves the condition of OSAS.

Computational fluid dynamics analysis for the preoperative prediction of airway changes after maxillomandibular advancement surgery

“…Maxillomandibular advancement (MMA) surgery, a type of sleep surgery, is used to treat OSA. In MMA, Le Fort type I osteotomy and sagittal splitting ramus osteotomy are performed to move the maxilla and mandibula anteriorly, and several studies reported favorable results for these procedures (6)(7)(8)(9)(10)(11)(12). MMA expands the upper airway; however, the degree of advancement required for therapeutic effectiveness is uncertain.…”

Computational Fluid Dynamic Study of Nasal Respiratory Function Before and After Bimaxillary Orthognathic Surgery With Bone Trimming at the Inferior Edge of the Pyriform Aperture

“…Recently, a number of researchers have been investigating human upper airway respiration using computational fluid dynamics (CFD). It has been reported that maxillary advancement increases pharyngeal volume, leading to improvement of OSA, [14][15][16] and that rapid maxillary expansion improves nasal ventilation. [17][18][19] Nevertheless, few studies have evaluated ventilation of the nasal cavity before/after maxillary impaction using CFD.…”

Pharyngeal airway morphology in healthy individuals and in obstructive sleep apnea patients treated with maxillomandibular advancement: a comparative study

“…22,23,[25][26][27][28][30][31][32] This has been proposed as the mechanism by which airway resistance is increased and air flow is compromised. 22,26,[33][34][35][36][37] As such, several studies have investigated the changes to the ratio of lateral to anteroposterior axial airway dimensions following MMA, but the results have been inconsistent. 22,26,27,32 To relate airway volume with airway length, Schendel et al 38 established values for the airway index of 1300 healthy individuals.…”