Postoperative Changes in the Upper Airway Following Mandibular Distraction Osteogenesis in Pediatric Hemifacial Microsomia

Abstract

Background: Patients with hemifacial microsomia (HFM) may undergo unilateral mandibular distraction osteogenesis (MDO) before skeletal maturity in an effort to improve facial symmetry. Mandibular distraction osteogenesis's effect on airway volumes have been studied in the past, though to our knowledge, none have accounted for the effect of head and neck posture on airway morphology. This study aimed to tackle this shortcoming, using imaging to analyze the upper airway of patients with HFM before and after surgical intervention with MDO. Methods/Description: The authors retrospectively reviewed patients with a diagnosis of unilateral HFM whom underwent unilateral MDO with an oblique vector at age 4 to 14 years at a single institution from 2004 to 2019. Patients with pre-and post-MDO three-dimensional computed tomography scans of the upper airway within 12 months of distractor placement and removal, respectively, were included. Head and neck postures were determined by craniocervical, pitch, roll, and yaw angles. Preand post-operative pharyngeal airway volumes, pharyngeal surface area, minimum retropalatal cross-sectional areas (RP CSA) and retroglossal (RG) CSA and associated anteroposterior distances were measured using Mimics 22.0 (Materialise; Leuven, Belgium). Comparison was done using Kruskal-Wallis tests and linear mixed-effects models controlling for head and neck postures.Results: Ten patients met inclusion criteria. Mean age at predistractor placement computed tomography scan was 99 AE 35 months, and mean duration between pre-and postsurgery scans was 220 AE 90 days. Head and neck posture were found to be significant predictors of all airway dimensions. After controlling for significant factors with fixed effects linear modeling, surface area was found to be significantly smaller in patients after MDO by 189.48 mm 2 (F[10.8] ¼ À3.47, P ¼ 0.0053), compared to their preoperative measurements. Surgery was not a significant predictor of changes in airway volume (F[11.6] ¼ 0.52, P ¼ 0.61), minimum RP CSA (F[12.2] ¼ À0.64, P ¼ 0.53), minimum RG CSA (F[12.6] ¼ À1.64, P ¼ 0.13), RP anteroposterior distance (F[14.0] ¼ 0.30, P ¼ 0.77), or RG anteroposterior distance (F[20.0] ¼ À0.04, P ¼ 0.97). Conclusions: Oblique vector MDO in patients with HFM is associated only with statistically significant changes in the surface area of the upper airway, and is not associated with statistically significant changes in dimensions like volume, CSA, or anteroposterior dimension. This is an important finding, as it may guide discussions surrounding risk/benefit ratio for MDO in childhood.

Kaban–Pruzansky Grade Predicts Airway Severity in Hemifacial Microsomia

“…However, there is a paucity of data as to which patients are at risk for clinically significant airway insufficiency. 3,4 The degree of facial and mandibular dysmorphology have also been shown to correlate with the incidence of airway compromise, such as obstructive sleep apnea (OSA). In severe cases of mandibular hypoplasia, patients may require either temporary or indefinite tracheostomy.…”