Anomalous venous collaterals in Apert and Crouzon syndromes and their relationship to ventricle size and increased intracranial pressure.

Objective: The exact association between the frequently present anomalous intracranial venous vasculature, emissary collaterals, ventriculomegaly, and increased intracranial pressure (ICP) in children with Apert and Crouzon syndromes remains an enigma. This study aimed to evaluate the association between the aberrant venous system and ventricle size and increased ICP, and to assess the development of the venous structures over time.

Methods: This retrospective cohort study included all patients with Apert or Crouzon syndrome with available CT venography (CTV) scans of the brain. Anomalous venous vasculature was assessed by the total collateral score (TCS), which scored 9 intra- and extracranial venous structures (TCS range 0-16). Ventricle size (fronto-occipital horn ratio [FOHR]) was measured on the same scan. The presence of increased ICP, a shunt, tonsillar herniation, and head circumference were extracted from electronic patient records and were used as secondary covariates. Subsequent CTV scans were scored when available.

Results: Ninety patients were included in this study. The mean TCS was 7.5 ± 2.5, and was comparable for patients with Apert and Crouzon syndromes (mean 8.0 and 7.3, respectively). The presence of an extra abnormal venous structure was associated with an increase of the FOHR of 3.2% (p < 0.01). After dividing the venous structures into intra- and extracranial, a similar association between both and the FOHR was found (4.1% and 2.3%, respectively; p < 0.01). The TCS was similar for patients with normal and increased ICP at the time of the scan. Sixteen patients had dual CTV scans. The median time between both scans was 3.2 years. The presence of collaterals remained stable over time (median ΔTCS = 0.3). Seven patients with functioning shunts also maintained high TCSs (median TCS = 9).

Conclusions: In patients with Apert and Crouzon syndromes, a close relationship between venous collaterals and ventricle size was observed, in which a more extensive aberrant venous drainage pattern, both intra- and extracranial, was associated with larger ventricles. Preliminary longitudinal data suggested that the presence of venous collaterals remained constant over time despite effective treatment of increased ICP, indicating reliance on these collaterals even in cases of normal ICP. The authors hypothesize that this dependence on collateral drainage is the result of their aberrant internal venous anatomy and predisposes individuals to increased ICP.