Pneumolacrimia: A Proposed Terminology and Classification System for Nasolacrimal Drainage System Aeration on...

Aeration of the nasolacrimal drainage system (NLDS) is an uncommon anatomical variant observed on computed tomography (CT) scans of the paranasal sinuses. Despite incidental identification, its clinical relevance remains unclear, and current literature is notably sparse, with only two publications on the topic; both authored by the same researcher and published outside otorhinolaryngology journals. The primary objective of this study is to characterize the radiological features of the nasolacrimal apparatus on CT, determine the prevalence of nasolacrimal pneumatization, and propose a standardized terminology and classification system, termed "pneumolacrimia." As a secondary, descriptive objective, we report the co-occurrence of nasolacrimal pneumatization with other sinonasal pneumatization patterns within the affected cohort, and propose a hypothesis, requiring further anatomical or functional validation, regarding a possible underlying mechanism Materials and methods: This retrospective study included 250 subjects (500 nasolacrimal apparatuses ) who underwent paranasal sinus CT imaging at a tertiary care hospital between 2023 and 2025, retrieved from the institutional Picture Archiving and Communication System (PACS). Prevalence is side-based. Cases showing air within the nasolacrimal apparatus were categorized as type I (partial aeration, <50% of vertical height) or type II (complete aeration, ≥50%). Associated paranasal sinus pneumatization patterns and anatomical variations were documented. Statistical analysis assessed correlations with age, gender, and other sinus variants.

Pneumolacrimia (air in the NLDS) was present in 27 (11%) cases, more commonly with complete aeration. No significant gender differences were found. The highest prevalence occurred in the 31-40-year age group. Concha bullosa was present in 30 (73.2%) of cases with NLDS aeration, 20 (66.67%) of which were ipsilateral. Sphenoid pneumatization most commonly followed type II pattern (21, 51.2%), while frontal sinuses were most often hyperplastic (24, 58.5%).

NLDS aeration, though rare, is a recognizable entity on CT and may reflect valvular insufficiency, agenesis, or dysfunction. We propose the term pneumolacrimia to describe this radiological finding and introduce a two-tier classification to aid in standardized reporting. Further anatomical and multicentric studies are needed to validate these findings and explore their clinical implications.