title: Incidence of superficial sylvian vein compromise and postoperative effects on CT imaging after surgical clipping of middle cerebral artery aneurysms.
abstract: OBJECTIVE
  Dissection and retraction of the sylvian fissure can cause venous insufficiency and may be an important contributor to postoperative edema or hemorrhage after clipping of a middle cerebral artery (MCA) aneurysm. The incidence of changes in the superficial middle cerebral vein (SMCV) and adjacent veins and whether such changes increase the amount of edema or hemorrhage on postoperative CT is the focus of this study.
  
  
  METHODS
  Pre- and postoperative angiograms of 100 consecutive patients with MCA aneurysms treated by craniotomy and clipping were compared to determine the postoperative incidence of changes involving the SMCV. CTs from the normal and abnormal postoperative venous groups were compared to determine the amount of edema or presence of parenchymal hemorrhage.
  
  
  RESULTS
  Postoperatively, 31 (31%) SMCVs were altered, 20 to a minor or moderate degree. Eleven cases were pronounced. In 9 (9%) cases, the SMCV was completely obscured or failed to fill on postoperative angiography. More edema (observer 1, P < .0002; observer 2, P < .0006) and small brain parenchymal hemorrhages (observer 1, P < .00003; observer 2, P < .00001) were found on the postoperative CT images of the group whose SMCVs were altered than those that were unchanged.
  
  
  CONCLUSIONS
  Neurosurgeons and neuroradiologists should be attentive to changes in the SMCV and adjacent venous structures to optimize outcomes of procedures involving the sylvian fissure.
authors.affiliation: Division of Neuroradiology, Barron Neurological Institute, Phoenix, AZ 85013, USA.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Dean
authors.forename: Robert C
authors.initials: RC
authors.lastname: Wallace
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Zabramski
authors.forename: Alan M
authors.initials: AM
authors.lastname: Pitt
authors.forename: C Roger
authors.initials: CR
authors.lastname: Bird
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
mesh_terms: D001929:Brain Edema / Q000000981:diagnostic imaging / Q000209:etiology; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology; D002550:Cerebral Veins / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed