Prevalence of frontal sinus agenesis in maxillofacial imaging and its forensic relevance – systematic review and meta-analysis

OBJECTIVES: the present study aimed to perform a systematic review and meta-analysis on the prevalence of frontal sinus agenesis. METHODS: A systematic review was conducted following PRISMA statement, with a preliminary protocol based on PRISMA-P registered in Open Science Framework and Zenodo. Searches were performed in PubMed/MEDLINE, Scopus, LILACS, SciELO, Open Access Theses and Dissertations and OpenGrey, complemented by additional screening through backward snowballing. Only observational studies reporting prevalence data on frontal sinus agenesis in maxillofacial imaging were selected. RESULTS: From 3614 records, 48 studies met eligibility criteria, and 47 were included in the quantitative synthesis. The pooled sample comprised 19,453 radiographic examinations spanning 22 countries. Bilateral frontal sinus agenesis showed a prevalence rate of 3,5% (n = 670 observations), while unilateral agenesis rate was 2,7% for the right side and 2,4% for the left side. Subgroup analyses revealed no significant differences based on sex, side, or imaging modality (2D vs. 3D). CONCLUSION: The synthesis of eligible studies showed that frontal sinus agenesis is a rare anatomical feature that can be recognized effectively using either 2D (posteroanterior or anteroposterior radiographic projections) or 3D (multislice or cone beam computed tomography) imaging. This consistency across modalities supports its practical value for clinical and diagnostic practice, and for human identification in the forensic routine.