Three-dimensional computed tomography in obstructive sleep apneics treated by maxillomandibular advancement

Area of Science:

• Orthodontics and Maxillofacial Surgery
• Sleep Medicine
• Radiology

Background:

• Class II dentoskeletal malocclusion with a high mandibular plane often correlates with obstructive sleep apnea.
• Skeletal malformations can impact pharyngeal airway dimensions and contribute to the apnea-hypopnea index (AHI).

Purpose of the Study:

• To investigate craniofacial skeletal and pharyngeal airway changes following segmental maxillomandibular rotational advancement (SMMRA).
• To determine the correlation between skeletal and airway modifications and the apnea-hypopnea index (AHI) post-SMMRA.

Main Methods:

• A prospective, noncontrolled pilot study involving 12 subjects with Class II malocclusion.
• Pre- and post-operative polysomnography and 3D CT scans were used to assess skeletal and airway dimensions.
• Linear and angular measurements were analyzed, and regression models were generated to correlate skeletal changes with AHI.

Main Results:

• SMMRA significantly reduced AHI from 35.9 to 4.6 and improved oxygen saturation.
• Skeletal advancements led to hyoid bone repositioning, cervical spine rotation, and airway length reduction.
• A quadratic regression model showed a correlation between the Sella-Nasion-B point angle and AHI (Rsq = 0.557).

Conclusions:

• Pharyngeal airway dimensions are significantly influenced by craniofacial skeletal morphology.
• The Sella-Nasion-B point angle serves as a valuable predictor for achieving normalized AHI after SMMRA surgery.