The postsurgical stability of oropharyngeal airway changes following maxillomandibular advancement surgery

Abstract

Statement of the Problem: The purpose of this study was to evaluate: 1) the oropharyngeal airway changes at four different levels in the oropharynx, associated with maxillomandibular advancement surgery, 2) cervical-head posture changes, and 3) the long-term stability of the oropharyngeal airway and cervical-head posture changes. Materials and Methods: The sample includes 56 adults (8 males and 48 females) between 15 and 51 years of age. They were treated with multiple maxillary osteotomies and bilateral sagittal split ramus osteotomies to advance the maxilla and mandible. They were followed for an average of 31.3 months postsurgery. Each subject’s lateral cephalograms were taken with clinical Frankfort horizontal plane parallel to the floor and were traced/digitized twice and averaged to estimate surgical changes (T2-T1) and postsurgical changes (T3-T2). Method of Data Analysis: Lateral cephalograms traced by a single author and digitized with Dentofacial Planner Software Inc, which aligns the tracings to be analyzed on the S-N coordinates. The data were exported to SPSS software statistical package. Results: During surgery, the maxilla underwent counterclockwise rotation and 2- to 4-mm advancement. The anterior aspect of the mandible was advanced a mean of 13.11 mm (range, 2.4 to 22.4 mm). Postsurgical hard tissue changes were small and not statistically significant. The upper airway decreased significantly 4.1 mm (UPW-UPWa) immediately after surgery, middle (MPWmin-RV and MPW-U) and lower (LPWmin-BT) oropharyngeal airway increased 2.9, 3.7, and 4.4 mm, respectively. Over the 31.3 months postsurgical period, upper oropharyngeal airway increased 3.9 mm while middle and lower airway remained stable. The cervical-head posture rotated clockwise after surgery (4.8 degrees) and counterclockwise postsurgery (1.6 degrees). Conclusion: We conclude that maxillomandibular advancement surgery produced immediate increases in middle and lower oropharyngeal airway remaining stable over the longest follow-up period; surgery also produced significant increases in upper airway which were temporarily obscured by postsurgical edema. References Mehra P, Downie M, Pita MC, et al: Pharyngeal airway space changes after counterclockwise rotation of the maxillomandibular complex. Am J Orthod Dentofac Orthop 120:154, 2001 Wolford LM, Chemello PD, Hilliard F: Occlusal plane alteration in orthognathic surgery. Part I: Effect on function and esthetics. Am J Orthod Dentofac Orthop 106:304, 1994 Muto T, Takeda S, Kanazawa M, et al: The effect of head posture on the pharyngeal airway space (PAS). Int J Oral Maxillofac Surg 31:579, 2002 Funding Source: FAPESP.