Route-Specific Meningo-Ophthalmic and Orbitomeningeal Communications Relevant to Middle Meningeal Artery Embolization: A Systematic Review and Meta-Analysis.

PURPOSE: Meningo-ophthalmic and orbitomeningeal arterial communications comprise route-specific relationships between the middle meningeal artery (MMA) and the ophthalmic or orbital arterial system. Their recognition is relevant to middle meningeal artery embolization because orbital or ophthalmic collateral pathways may create routes for non-target embolization. This systematic review aimed to synthesize the prevalence and anatomical patterns of these communications, using quantitative pooling only where the anatomical definition and denominator were sufficiently coherent.

METHODS: This systematic review and meta-analysis were conducted according to PRISMA 2020 principles and registered in PROSPERO (CRD420261361050). Eligible studies were original human cadaveric anatomical, angiographic, or radiological investigations reporting MMA-ophthalmic or MMA-orbital arterial relationships. After the closure of the full-text retrieval audit, studies and extracted rows were audited by anatomical family, unit of analysis, numerator, denominator, and independence. No global pooled prevalence was calculated across anatomical families. When family-specific pooling was methodologically defensible, proportions were synthesized using logit transformation, restricted maximum likelihood random-effects models, and Hartung-Knapp confidence intervals.

RESULTS: Database searches identified 558 records. After removal of 228 duplicates, 330 records were screened, and 285 were excluded by title and abstract. Forty-five reports were sought for retrieval; 10 were not retrieved or were not available as assessable full-text reports after retrieval auditing. Thirty-five full-text reports were assessed; thirteen were excluded for reasons, and three were duplicate reports at the full-text stage. Nineteen studies were included in the qualitative synthesis, and 12 contributed independent data to the final R-ready matrix. MMA arising from the ophthalmic artery was uncommon, with a pooled prevalence of 0.03 (95% CI 0.01 to 0.13; I2 = 75.9%). After excluding the clinically selected chronic subdural hematoma subgroup, the estimate was 0.02 (95% CI 0.01 to 0.06; I2 = 7.7%). The meningolacrimal/lacrimal-MMA route yielded an exploratory pooled proportion of 0.45 (95% CI 0.09 to 0.86; I2 = 95.9%), with substantial anatomical and methodological heterogeneity.

CONCLUSIONS: The available evidence supports route-specific synthesis rather than a single global prevalence estimate. MMA arising from the ophthalmic artery appears uncommon but procedurally important; however, this estimate should be interpreted as a route-specific estimate across eligible angiographic/anatomical series rather than as a universal anatomical prevalence. Meningolacrimal and lacrimal-MMA routes are frequently described, but their prevalence remains difficult to generalize because detection methods, populations, and denominators differ across studies. Future anatomical and angiographic reports should standardize route definitions, laterality, unit of analysis, and denominator reporting to improve prevalence estimation and procedural safety interpretation.