Postsurgical volumetric airway changes in 2-jaw orthognathic surgery patients.
BACKGROUND
Findings from early cephalometric studies on airway changes after 2-jaw orthognathic surgery have been challenged because the previous anteroposterior interpretation of airway changes can now be evaluated in 3 dimensions. The aims of this study were to use cone-beam computed tomography to quantify the nasopharynx, oropharynx, and total airway volume changes associated with skeletal movements of the maxilla and mandible in a sample of patients undergoing 2-jaw orthognathic surgery for correction of skeletal malocclusion.


METHODS
Skeletal movements and airway volumes of 71 postpubertal patients (31 male, 40 female; mean age, 18.8 years) were measured. They were divided into 2 groups based on ANB angle, overjet, and occlusion (Class II: ANB, >2°; overjet, >1 mm; total, 35 subjects; and Class III: ANB, <1°; overjet, <1 mm; total, 36 subjects). Presurgical and postsurgical measurements were collected for horizontal, vertical, and transverse movements of the maxilla and the mandible, along with changes in the nasopharynx, oropharynx, and total airways. Associations between the directional movements of skeletal structures and the regional changes in airway volume were quantified. Changes in the most constricted area were also noted.


RESULTS
Horizontal movements of D-point were significantly associated with increases in both total airway (403.6 ± 138.6 mm(3); P <0.01) and oropharynx (383.9 ± 127.9 mm(3); P <0.01) volumes. Vertical movements of the posterior nasal spine were significantly associated with decreases in total airway volume (-459.2 ± 219.9 mm(3); P = 0.04) and oropharynx volume (-639.7 ± 195.3 mm(3); P <0.01), increases in nasopharynx (187.2 ± 47.1 mm(3); P <0.01) volume, and decreases in the most constricted area (-10.63 ± 3.69 mm(2); P <0.01). In the Class III patients only, the vertical movement of D-point was significantly associated with decreases in both total airway (-724.0 ± 284.4 mm(3); P = 0.02) and oropharynx (-648.2 ± 270.4 mm(3); P = 0.02) volumes. A similar negative association was observed for the most constricted area for the vertical movement of D-point (-15.45 ± 4.91 mm(2); P <0.01).


CONCLUSIONS
Optimal control of airway volume is through management of the mandible in the horizontal direction and the vertical movement of the posterior maxilla for all patients. The surgeon and the orthodontist should optimally plan these movements to control gains or losses in airway volume as a result of orthognathic surgery.
Private practice, Woodridge, Va.
P Sheamus
PS
Hart
Private practice, Omaha, Neb.
Brian P
BP
McIntyre
Assistant professor and program director, Department of Orthodontics, University of Oklahoma, Oklahoma City, Okla. Electronic address: onur-kadioglu@ouhsc.edu.
Onur
O
Kadioglu
Professor and chair, Department of Orthodontics, University of Oklahoma, Oklahoma City, Okla.
G Fräns
GF
Currier
Professor and chair, Department of Oral and Maxillofacial Surgery, University of Oklahoma, Oklahoma City, Okla.
Steven M
SM
Sullivan
Biostatistician, Department of Biostatistics and Epidemiology, University of Oklahoma, Oklahoma City, Okla.
Ji
J
Li
Assistant professor, Department of Biostatistics and Epidemiology, University of Oklahoma, Oklahoma City, Okla.
Christina
C
Shay
D000293:Adolescent; D000328:Adult; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery; D008313:Malocclusion, Angle Class III / Q000601:surgery; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery; D009295:Nasal Bone / Q000000981:diagnostic imaging; D009305:Nasopharynx / Q000000981:diagnostic imaging; D009929:Organ Size; D009960:Oropharynx / Q000000981:diagnostic imaging; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D057887:Overbite / Q000601:surgery; D010614:Pharynx / Q000000981:diagnostic imaging*; D014716:Vertical Dimension; D055815:Young Adult