title: Preoperative evaluation of the venous system for potential interference in the clipping of cerebral aneurysm.
abstract: BACKGROUND
  Variations of the venous system affecting the surgical treatment of cerebral aneurysm were evaluated using three-dimensional computed tomography angiography (3D-CTA) to evaluate the essential aspects of preoperative diagnosis.
  
  
  METHODS
  This study included 50 patients who underwent clipping of cerebral aneurysm through the pterional and trans-sylvan approaches. The 3D-CTA and operative findings were compared to assess the characteristics of cases in which the veins restrict brain retraction, hinder operative manipulations or require sacrifice because of the position in the operative field.
  
  
  RESULTS
  Superficial sylvian veins that restricted brain retraction were identified in 8 cases. The veins entered the cavernous sinus in a relatively high position just below either the sphenoid ridge (superior lateral type) or the anterior clinoid process (superior medial type), and the veins entering at a more medial position were closer to the spatula and tended to be compressed or directly excluded (superior medial type). The inferior medial type did not tend to become tense and so did not restrict brain retraction. The inferior lateral type hardly affected the operative manipulation. The first segment of the basal vein of Rosenthal, the uncal vein entering the cavernous sinus, or the sphenoparietal sinus were located in the operative field in six cases, and affected the manipulation of dissecting arteries, and exposure and clipping of the aneurysm.
  
  
  CONCLUSIONS
  3D-CTA provides essential information for operative planning to protect the venous system during the pterional and trans-sylvian approaches.
authors.affiliation: Department of Neurosurgery, SECOMEDIC Hospital, Funabashi, Chiba, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Masateru
authors.initials: M
authors.lastname: Nakajima
authors.forename: Hisato
authors.initials: H
authors.lastname: Ikeda
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Takumi
authors.initials: T
authors.lastname: Abe
mesh_terms: D001921:Brain / Q000098:blood supply*; D002343:Carotid Artery, Internal / Q000473:pathology* / Q000601:surgery*; D002533:Cerebral Angiography / Q000379:methods*; D002550:Cerebral Veins / Q000033:anatomy & histology; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000601:surgery*; D010347:Patient Care Planning; D011183:Postoperative Complications / Q000517:prevention & control; D011237:Predictive Value of Tests; D011300:Preoperative Care; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed