Introduction: Although it has been more than 250 years since the first description of choanal atresia (CA), there are still doubts about this abnormality. The differences between unilateral and bilateral forms are seldom discussed.

Objectives: Aggregate data from patients diagnosed with CA, grouping patients with unilateral and bilateral forms.

Methods: Retrospective study.

Results: Eighteen patients were included: 12 (66.6%) presented bilateral atresia, of which 77.8% were mixed bony-membranous type and 22.2% were pure bony type. From the 12 patients with bilateral atresia, 10 presented related malformations, 3 of whom had CHARGE syndrome (coloboma, heart defects, choanal atresia, retardation of growth and development, genitourinary problems, ear abnormalities). From the remaining 6 patients with unilateral atresia, only 2 showed malformations, 1 renal and 1 cardiac. All patients with unilateral atresia needed only 1 surgical procedure, and patients with the bilateral form needed a median of 2.85 interventions (p = 0.003). The median age of surgical procedure in the unilateral group was 6 years, ranging from 6 months to 18 years, and in the bilateral group was 25 days, ranging from 6 days to 6 years (p = 0.003). The median interval between diagnosis and surgery was 9 months in the unilateral group, ranging from 1 month to 18 years, and in the bilateral group was 1 day, ranging from 1 day to 2 months (p = 0.001).

Discussion and Conclusions: Success rates with the endoscopic approach vary from 62 to 100%. Nonetheless, most of these reports present results without considering the number of compromised sides. In our opinion, unilateral and bilateral cases involve distinct patients (taking into account the related malformations), have diverging clinical presentations, and show discrepant restenosis rates and therefore could be considered in different groups of analysis.