title: Anatomical variants of the basal vein of Rosenthal: prevalence in idiopathic subarachnoid hemorrhage.
abstract: BACKGROUND
  Spontaneous, non traumatic subarachnoid hemorrhage (SAH) is a significant clinical problem that occurs most commonly as a result of aneurysm rupture. In approximately 15 % of cases, nor aneurysm or other vascular malformation can be identified by cerebral angiography as origin of the hemorrhage, and these are commonly defined as idiopathic SAH (ISAH). Because of the negative angiography, limited extension of the bleeding with prevalent prepontine pattern and the benign prognosis, the venous causes has been preferred rather than the arterial ones. In the literature recent studies have suggested a possible contribution by primitive variants of Basal vein of Rosenthal (BVR) in its the pathogenesis of ISAH, commonly grouped according Watanabe classification (type A, B and C). In this paper we evaluated the prevalence of anatomical variants of BVR in ISAH.
  
  
  METHODS
  Venous drainage at angiography was retrospectively analyzed in 40 patients with ISAH and in 40 with unruptured aneurysms as controls.
  
  
  CONCLUSIONS
  Previous studies displayed a significant prevalence of BVR type C variants in ISAH. Conversely in our study we recognized variant B as prevalent, in which the BVR bifurcates to drain anteriorly into the uncal vein and posteriorly into the Galenic system. Similarly to variant C (in which the BVR drains via perimesencephalic "bridging" veins into cavernous, sphenoparietal, petrosal sinus or directly into transverse sinus) also variant B might be subjected to those stress mechanisms and intrinsic system 'fragility' and for reasons yet to determine, sets off a consequent hemorrhage with clinical and radiological features typical of ISAH.
authors.affiliation: Institute of Neurosurgery, Catholic University of Rome, Largo A. Gemelli 8, 00168, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sabatino
authors.forename: Giuseppe Maria
authors.initials: GM
authors.lastname: Della Pepa
authors.forename: A
authors.initials: A
authors.lastname: Scerrati
authors.forename: G
authors.initials: G
authors.lastname: Maira
authors.forename: M
authors.initials: M
authors.lastname: Rollo
authors.forename: A
authors.initials: A
authors.lastname: Albanese
authors.forename: E
authors.initials: E
authors.lastname: Marchese
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D002533:Cerebral Angiography / Q000379:methods; D002550:Cerebral Veins / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy