Skull Base Anatomy in Charge Patients with Bilateral Choanal Atresia

Background: Bilateral choanal atresia (BCA) repair is necessary in neonates as they are obligate nasal breathers. The risk of skull base injury during choanal atresia repair can be mitigated via thorough understanding of skull base anatomy. There is a paucity of data describing differences in skull base anatomy between patients with CHARGE syndrome and those without.

Objectives: To measure nasal and skull base anatomy in patients with isolated bilateral choanal atresia, CHARGE syndrome, and other severe congenital abnormalities to provide low-risk surgical repair.

Methods: A retrospective chart review was conducted of all patients with bilateral choanal atresia with computed tomography images of the maxillofacial region between 2001 and 2019. Choanal width, height, midnasal height, and skull base slope were measured radiographically. Differences in anatomy between healthy patients, those with CHARGE syndrome, and those with other congenital anomalies were compared.

Results: A total of 21 patients with BCA and relevant imaging were identified: 7 with isolated BCA, 6 with CHARGE syndrome, and 8 with other congenital abnormalities of varying severity. The small sample size of this study did not demonstrate significant differences between the groups with respect to choanal height or skull base slope (p > 0.05). With equal variance between CHARGE and normal groups, a t-test indicated insignificant difference between CHARGE skull base slope and normal patient skull base slope. A similar result of insignificant difference in skull base slope was found between CHARGE and the congenital abnormality group. When comparing CHARGE group to congenital abnormality group and normal patient group (separately), with equal variance, a t-test indicated insignificant difference in midnasal skull base height. Patients with concurrent significant congenital abnormalities, not including CHARGE, were found to have a higher incidence of bony atresia versus membranous. Two patients in the congenital anomaly group were found to have skull base defects preoperatively.

Conclusion: Currently, this study represents the largest description of skull base and nasal anatomy in patients with CHARGE syndrome and BCA. While no statistical significant difference was identified due to the small sample size of this study, these measurements may approach significance with larger sample size and aid in the avoidance of skull base injury during BCA repair.