QS1: Nasopharyngeal Airway and Subcranial Space Analysis in Pfeiffer Syndrome

BACKGROUND: Tracheotomy in infancy helps patients with Pfeiffer syndrome survive by preventing respiratory crisis, however, difficulty in decannulation consequently may be a challenge. This study attempts to investigate the regional abnormalities of the nasopharyngeal airway in Pfeiffer syndrome, to provide an anatomic basis for the upper airway surgical treatment and decannulation. METHOD: Seventy-two preoperative CT scans (Pfeiffer syndrome, n=30; control, n=42) were included in this study. The airway volume, cross-sectional area, and cephalometrics, were measured using Materialise software. RESULTS: Patients with Pfeiffer syndrome developed a 50% (p<0.001) reduction of nasal airway volume, and a 44% (p=0.003) restriction in pharyngeal airway volume. The cross-sectional area of Pfeiffer patients at the choana, was only half that of normals’ (p<0.001). The posterior width of nasal airway in Pfeiffer syndrome was shortened by 13% (p=0.003), and the height was reduced by 21% (p<0.001). The cross-sectional areas at condylion and gonion levels, indicating the caliber of pharyngeal airway at entrance and midsection, were reduced by 67% (p<0.001) and 47% (p<0.001), respectively, when compared with normals. CONCLUSION: Nasal airway volume in Pfeiffer syndrome is significantly restricted, in length, height and width, along with the choanal stenosis in all cases in this cohort. The reduced anteroposterior length of nasal airway contributes to the shortened maxilla, more than the anteroposterior position. The limited nasal pathway height and width results from the hypoplastic sphenoid. Mediolateral and anteroposterior restricted dimensions are evident across the entire course of pharyngeal airway. Therefore, mediolateral maxillary expansion likely benefits Pfeiffer syndrome patients, in addition to maxillomandibular advancement.