Modified maxillomandibular advancement for eastern Asian patients with moderate or severe OSA: a study on anatomic and aerodynamic assessment of upper airway

Kan Li^1,2Tianyu Zhao^1,2Yukun Liu^1,2Zhicai Feng^1,2Xiang Li^1,2Siyong Gao^1,2Wei Sun^1,2Tao Wang^1,2,3,4,5Lingchan Zeng^1,2Guangsen Zheng^1,2*Yang Cao^1,2*

• ¹Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
• ²Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
• ³College of Stomatology, Chongqing Medical University, Chongqing, China
• ⁴Chongqing Key Laboratory of Oral Diseases, Chongqing, China
• ⁵Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China

Background/purpose Maxillomandibular advancement( MMA) has been widely used in the treatment for OSA patients. However, this conventional MMA may not be suitable for eastern Asian patients with moderate or severe OSA, which probably results in unsatisfactory postoperative appearance. Hence, modified MMA was reported. Our study aims to evaluate therapeutic effect on OSA and satisfaction of facial appearance after modified MMA. The changes of upper airway were further explored anatomically and aerodynamically. Materials and methods This was a retrospective study of 13 patients with moderate or severe OSA. Overnight polysomnographic (PSG) and Epworth sleepiness score (ESS) were recorded before operation and 6 months after operation, to evaluate the therapeutic effect. Spiral CT scans were conducted for all patients, which were used to reconstruct 3D configurations of the bony structures and the upper airways. Computational Fluid Dynamics CFD )was performed to analyze aerodynamic characteristics. Underlying correlation between movement of bone segments and improvement of airway parameter was also revealed. Results Modified MMA achieved successful therapeutic and aesthetic results in all cases. Apnea hypopnea index (AHI, 36.05±17.68 vs 5.72±4.76,p<0.001) and ESS 13.23±8.9 events/h vs 6.23±6.81 events/h,p<0.05) were significantly decreased, while the lowest saturation (LSAT,76.54±10.26% vs 84.77±6.02 %,p<0.05) was greatly improved. Modified MMA significantly increased the total volume (6716.55±1357.73mm3 vs 11191.28±2563.79mm3, p<0.001) and averaged cross-sectional area( 117.38±24.25 mm2 vs 201.58±35.76 mm2, p<0.001)of upper airway. Pressure drop, velocity of the gas and resistant in the upper airway were significantly decreased after modified MMA p< 0.05). Among all the maxillary and mandible sections, the strongest correlation was observed between the advanced movement of the anterior mandible segment and anatomical characteristics of the upper airway. Conclusion Modified MMA is an excellent therapeutic method for the eastern Asian population with skeletal class Ⅱ dentomaxillofacial deformity suffering from moderate or severe OSA, which achieves a balance between improvement for appearance and therapy for OSA anatomically and aerodynamically.