The thyroid foramen: a systematic review and meta-analysis

Purpose: To systematically review published studies on the prevalence of the thyroid foramen (TF), perform a meta-analysis to generate pooled prevalence estimates, and identify factors associated with its presence. Methods: A systematic literature search was conducted in Google Scholar, PubMed, and Journal Storage databases. Studies reporting the prevalence of the thyroid foramen were included without language or date restrictions. Quality assessment was performed using AQUA tool. A random-effects meta-analysis was performed with subgroup analyses. Heterogeneity was assessed using Higgins’ I² statistics, and publication bias was evaluated using funnel plots and Egger’s test. Results: Out of 271 entries, 38 studies met the inclusion criteria, comprising 3,030 subjects from various continents. The overall TF prevalence was 24.5% (95% CI: 19.2-29.8%, I² = 93.44%), with unilateral TF present in 16.9% and bilateral TF in 6.2%. Prevalence was highest in North America (31.4%,) and lowest in Africa (12.3%). No significant prevalence difference was found between adults and younger populations (p = 0.15). Publication bias, or the small-study effect, was detected (p < 0.01). Conclusion: This meta-analysis reveals a 24.5% overall prevalence of TF, with significant heterogeneity primarily explained by geographical differences. The TF’s clinical relevance necessitates awareness among surgeons and radiologists to avoid complications during laryngeal surgeries and prevent misdiagnosis in imaging studies.