Venous anomalies in hypoplastic posterior fossa: unsolved questions.

Abstract

Anomalous intracranial venous anatomy is described in patients with syndromic craniosynostosis andis of significant importance when it comes to surgical morbidity. However, it is still controversial its origin, type ofcirculation in each syndrome, how it behaves over time, when it can be interrupted and wether it needs to bestudied. The purpose of this paper is to discuss these issues by reviewing the literature. A literature search was performed using the PubMed database with a focus on papers including detaileddescriptions of the venous outflow in complex and syndromic craniosynostosis. Search details used were thefollowing: ("veins"[MeSH Terms] OR "veins"[All Fields] OR "venous"[All Fields]) AND ("abnormalities"[Subheading]OR "abnormalities"[All Fields] OR "anomalies"[All Fields]) AND syndromic[All Fields] AND ("craniosynostoses"[MeSH Terms] OR "craniosynostoses"[All Fields] OR "craniosynostosis"[All Fields]). Studies that exposed details ofvenous anomalies found in syndromic or complex craniosynostosis were selected. Of a total of 211 articles found, 11 were selected for this review. Of these, 5 were case reports, 5retrospective studies, and only 1 prospective study. From the 6 series of cases presented, 5 discussed therelationship between jugular foramen stenosis (JFS) and collateral venous drainage. The authors discuss data fromthe literature for each leading question presented: 1-collateral circulation: is it an intrinsic trouble, a consequenceof stenosis of the cranial base foramina or related to raised intracranial pressure (ICP)?; 2-what venousanomalies should we search for, and what is the best exam to study them?; 3-collateral circulation changes withtime?; 4-can neurosurgeons interrupt the collateral circulation?; 5-should we study all complex types ofcraniosynostosis? The importance of the study of the venous outflow in patients with complex craniosynostosis is evidentin the literature. The real relationship between intracranial hypertension, hypoplastic skull base foramen, Chiari Imalformation, hydrocephalus, and venous collateral circulation remains unknown. Prospective studies focusing onmolecular biology analysis will possibly solve all of these leading questions.