title: Thrombotic intracranial aneurysms: classification scheme and management strategies in 68 patients.
abstract: OBJECTIVE
  Thrombotic aneurysms are a diverse collection of complex aneurysms characterized by organized intraluminal thrombus and solid mass. Consequently, their treatment often requires techniques other than conventional clipping, such as thrombectomy with clip reconstruction or bypass with parent artery occlusion. A single-surgeon experience with thrombotic aneurysms was analyzed to determine optimal treatment strategies. A classification scheme was devised on the basis of aneurysm, thrombus, and lumen morphology to relate these anatomic features to surgical therapy.
  
  
  METHODS
  Sixty-eight patients with thrombotic aneurysms were managed during a period of 6.25 years. Thrombotic aneurysms were classified into six types: concentric (n = 17, 25%), eccentric (n = 14, 21%), lobulated (n = 2, 3%), complete (n = 2, 3%), canalized (n = 17, 25%), and coiled (n = 16, 24%).
  
  
  RESULTS
  Aneurysm management consisted of direct clipping (n = 22, 32%), thrombectomy-clip reconstruction (n = 18, 26%), bypass-occlusion (n = 20, 29%), other (n = 6, 9%), or observation (n = 2, 3%). Complete angiographic obliteration was achieved in 97% of patients, and 47% of aneurysms were thrombectomized. The surgical mortality rate was 6%, and the permanent neurological morbidity rate was 7%. Overall, 87% of patients were improved or unchanged at follow-up, with 79% reaching a Glasgow Outcome Scale score of 5 or 4. Management strategy was influenced by thrombotic aneurysm type, but patient outcome was not. The best results were observed in patients treated with direct clipping and bypass-occlusion.
  
  
  CONCLUSIONS
  Despite their solid mass, one-third of thrombotic aneurysms can be treated surgically with conventional clipping. Direct clipping is associated with the best surgical results, and the proposed classification scheme identifies thrombotic aneurysms that may be clippable. Patients with unclippable thrombotic aneurysms had more favorable results when treated with bypass and aneurysm occlusion than with thrombectomy and clip reconstruction. The classification scheme may provide conceptual clarity and therapeutic guidance with preoperative and intraoperative decision making.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, San Francisco, California 94143-0112, USA. lawtonm@neurosurg.ucsf.edu
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lawton
authors.forename: Alfredo
authors.initials: A
authors.lastname: Quiñones-Hinojosa
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
authors.forename: Timothy
authors.initials: T
authors.lastname: Yu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology; D002545:Brain Ischemia / Q000209:etiology; D019090:Case Management; D002533:Cerebral Angiography; D002548:Cerebral Revascularization; D002648:Child; D003131:Combined Modality Therapy; D004621:Embolization, Therapeutic; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D002532:Intracranial Aneurysm / Q000145:classification* / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery* / Q000628:therapy; D020767:Intracranial Thrombosis / Q000145:classification* / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000209:etiology / Q000601:surgery; D013525:Surgical Instruments; D017131:Thrombectomy; D016896:Treatment Outcome