Quantitative changes of upper airway in class III patients undergoing bimaxillary surgery after one-year follow-up: a retrospective study

Exploring long-term changes and influencing factors of the upper airway in patients with a skeletal Class II relationship after mandibular advancement with maxillary setback surgery: A comprehensive 2-year follow-up investigation

INTRODUCTION

The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship.

METHODS

Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif).

RESULTS

The total volume (V), minimum cross-sectional area (CSAmin), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSAmin, 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSAmin, 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSAmin, and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 - T1] / T1) of V and CSAmin.

CONCLUSIONS

Mandibular advancement amount, mandibular width increase, preoperative CSAmin, and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate.

MSCT 3D Analysis of Nasopharyngeal Airway After Le Fort I Maxillary Setback Surgeries

In recent years, maxillary Le Fort I osteotomy setback has been widely applied in correcting maxilla prognathism. In the meantime, airway considerations have attracted more and more attention. The aim of this research was to observe the alteration of nasopharyngeal airway indexes after maxilla setback and offer evidence for the effectiveness and safety of maxillary Le Fort I setback surgeries. As for a retrospective cross-sectional study, 40 patients diagnosed with maxilla prognathism and undergoing maxillary setback surgeries were enrolled. They were grouped by the type of maxillary setback operations as group A (integral maxillary setback, n=19) and group B (segmental maxillary setback, n=21). Multislice computed tomography data were collected 1 week before (T0) and more than 3 months (T1) after surgery. 3D reconstruction and evaluation of the pharyngeal airway were conducted to analyze nasopharyngeal airway index variation before and after surgery and the difference between group A and group B. Preoperative and postoperative nasopharyngeal airway volume showed no statistical significance in group A (P=0.872) and group B (P=0.169) as well as other indexes of the nasopharynx. The comparison of postoperative airway changes between group A and group B also showed no significant difference. Both integral and segmental maxillary Le Fort I osteotomy setbacks have slight impact on nasopharyngeal airway dimensions and are safe within a specific setback range.