Infraorbital Ethmoid Cells (Haller Cells) and Their Role in Chronic Rhinosinusitis: An Evidence-Based Meta-Analysis

Background: Haller cells (HCs), infraorbital pneumatization of the anterior ethmoidal air cells, are anatomical variants frequently located adjacent to the maxillary sinus ostium. Their presence has been hypothesized to interfere with mucociliary drainage and contribute to the pathophysiology of chronic rhinosinusitis (CRS). Despite numerous imaging-based investigations, the etiological role of Haller cells in CRS remains uncertain. The aim of this meta-analysis is to highlight the association between HC and CRS using data derived from Computed Tomography (CT) and Cone-Beam Computed Tomography (CBCT) imaging. Materials and Methods: Following PRISMA guidelines and a registered protocol in the PROSPERO database, a systematic search across PubMed, EMBASE, and COCHRANE databases led to the inclusion of eight studies published between 2011 and 2024, comprising 2011 patients. The included studies employed multiplane reconstruction techniques and high-resolution imaging protocols. The majority of studies were retrospective, with only one adopting a prospective design. Results: The pooled odds ratio (OR) for the association between HC and CRS was 1.54 (95% Confidence Interval: 0.93–2.54; p = 0.09), suggesting a non-significant trend toward a positive correlation. Heterogeneity was substantial (I2 = 87%, p < 0.01), due to differences in study design, populations, and diagnostic criteria, contributing to inconsistency in reported estimates across the studies. Moreover, Egger’s test showed no evidence of publication bias (intercept = 0.67, p = 0.895). Although three studies fulfilled all eleven evaluation criteria outlined by the JBI (Joanna Briggs Institute) checklist, the observed variability limits the interpretability of pooled outcomes. Conclusions: These findings suggest that, while HC may play a role in CRS pathogenesis, the current evidence does not support a statistically significant association. Future prospective research using standardized imaging and diagnostic criteria is essential to clarify the clinical impact of HC in sinonasal disease.