Unruptured intracranial aneurysms: a review

Journal of Neurosurgery - Tập 96 Số 1 - Trang 3-42 - 2002
Bryce Weir1
1Section of Neurosurgery, The University of Chicago, Illinois 60637-1470, USA.

Tóm tắt

Object. In this article, pathological, radiological, and clinical information regarding unruptured intracranial aneurysms is reviewed. Methods. Treatment decisions require that surgeons and interventionists take into account information obtained in pathological, radiological, and clinical studies of unruptured aneurysms. The author has performed a detailed review of the literature and has compared, contrasted, and summarized his findings. Unruptured aneurysms may be classified as truly incidental, part of a multiple aneurysm constellation, or symptomatic by virtue of their mass, irritative, or embolic effects. Unruptured aneurysms with clinical pathological profiles resembling those of ruptured lesions should be considered for treatment at a smaller size than unruptured lesions with profiles typical of intact aneurysms, as has been determined at autopsy in patients who have died of other causes. The track record of the surgeon or interventionist and the institution in which treatment is to be performed should be considered while debating treatment options. In cases in which treatment is not performed immediately, ongoing periodic radiological assessment may be wise. Radiological investigations to detect unruptured aneurysms in asymptomatic patients should be restricted to high-prevalence groups such as adults with a strong family history of aneurysms or patients with autosomal dominant polycystic kidney disease. All patients with intact lesions should be strongly advised to discontinue cigarette smoking if they are addicted. Conclusions. The current state of knowledge about unruptured aneurysms does not support the use of the largest diameter of the lesion as the sole criterion on which to base treatment decisions, although it is of undoubted importance.

Từ khóa


Tài liệu tham khảo

Allcock, 1976, Angiographic study of the growth of intracranial aneurysms., 45, 617, 10.3171/jns.1976.45.6.0617

Asari, 1992, Surgical management of the unruptured cerebral aneurysm accompanied by ischemic cerebrovascular disease., 94, 119, 10.1016/0303-8467(92)90068-E

Asari, 1993, Natural history and risk factors of unruptured cerebral aneurysms., 95, 205, 10.1016/0303-8467(93)90125-Z

Austin, 1989, Controlled pressure—volume factors in the enlargement of intracranial aneurysms., 24, 722, 10.1227/00006123-198905000-00011

Bederson, 2000, Recommendations for the management of patients with unruptured intracranial aneurysms: a statement for healthcare professionals from the Stroke Council of the American Heart Association., 31, 2742, 10.1161/01.STR.31.11.2742

Björkesten, 1962, Changes in the size of intracranial arterial aneurysms., 19, 583, 10.3171/jns.1962.19.7.0583

Black, 1988, Recording and measuring the interior features of intracranial aneurysms removed at autopsy: method and initial findings., 22, 40

Bonita, 1986, Cigarette smoking, hypertension and the risk of subarachnoid hemorrhage: a population-based case-control study., 17, 831, 10.1161/01.STR.17.5.831

Boulin, 2001, Follow-up of intracranial aneurysms treated with detachable coils: comparison of gadolinium-enhanced 3D time-of-flight MR angiography and digital subtraction angiography., 219, 108, 10.1148/radiology.219.1.r01mr06108

Bowen, 1984, Ruptured berry aneurysms: a clinical, pathological and forensic review., 26, 227, 10.1016/0379-0738(84)90027-6

Brennan, 2000, Unruptured intracranial aneurysms: appraisal of the literature and suggested recommendations for surgery, using evidence-based medicine criteria., 47, 1359, 10.1097/00006123-200012000-00019

Brett, 1999, Unruptured intracranial aneurysms., 340, 1441

Brilstra, 1999, Treatment of intracranial aneurysms by embolization with coils: a systematic review., 30, 470, 10.1161/01.STR.30.2.470

Broderick, 1992, The risk of subarachnoid and intracerebral hemorrhages in blacks as compared to whites., 326, 733, 10.1056/NEJM199203123261103

Brown, 1999, MR angiography and surgery for unruptured familial intracranial aneurysms in persons with a family history of cerebral aneurysms., 173, 133, 10.2214/ajr.173.1.10397113

Brown, 1990, Unruptured intracranial aneurysms and arteriovenous malformations: frequency of intracranial hemorrhage and relationship of lesions., 73, 859, 10.3171/jns.1990.73.6.0859

Butler, 1996, Patients with polycystic kidney disease would benefit from routine magnetic resonance angiographic screening for intracerebral aneurysms: a decision analysis., 38, 506

Caplan, 1998, Should intracranial aneurysms be treated before they rupture?, 339, 1774, 10.1056/NEJM199812103392409

Carter, 2001, What determines outcome for surgically treated unruptured intracranial aneurysms?, 94, 165A

Chaloupka, 2001, Incidence in a university referral population of aneurysms smaller than 10 mm that have ruptured: practical and theoretical implications., 94, 171A

Chang, 1995, Quantification of operative benefit for unruptured cerebral aneurysms: a theoretical approach., 83, 413, 10.3171/jns.1995.83.3.0413

Chapman, 1992, Intracranial aneurysms in autosomal dominant polycystic kidney disease., 327, 916, 10.1056/NEJM199209243271303

Chason, 1958, Berry aneurysms of the Circle of Willis. Results of a planned autopsy study., 8, 41, 10.1212/WNL.8.1.41

Chauveau, 1994, Intracranial aneurysms in autosomal dominant polycystic kidney disease., 45, 1140, 10.1038/ki.1994.151

Chyatte, 2001, Functional outcome after repair of unruptured intracranial aneurysms., 94, 417, 10.3171/jns.2001.94.3.0417

Cloft, 1999, Risk of cerebral angiography in patients with subarachnoid hemorrhage, cerebral aneurysm, and arteriovenous malformation: a meta-analysis., 30, 317, 10.1161/01.STR.30.2.317

Cohen, 1955, Cerebrovascular accidents. A study of two hundred one cases., 60, 296

Connolly, 2001, Influence of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms in siblings., 48, 64

Crompton, 1966, Mechanism of growth and rupture in cerebral berry aneurysms., 1, 1138, 10.1136/bmj.1.5496.1138

David, 1999, Late angiographic follow-up review of surgically treated aneurysms., 91, 396, 10.3171/jns.1999.91.3.0396

de la Monte, 1985, Risk factors for the development and rupture of intracranial berry aneurysms., 78, 957, 10.1016/0002-9343(85)90218-9

Deruty, 1996, Management of unruptured cerebral aneurysms., 18, 39, 10.1080/01616412.1996.11740375

Dickey, 1994, Intracranial aneurysms: size, risk of rupture, and prophylactic surgical treatment., 58, 583

Dix, 1995, Ruptured and unruptured intracranial aneurysms—surgical outcome., 22, 187, 10.1017/S0317167100039822

Easton, 1993, Management of unruptured aneurysms., 3, 60, 10.1159/000108673

Eskesen, 1988, The influence of unruptured intracranial aneurysms on life expectancy in relation to their size at the time of detection and to age., 2, 379, 10.3109/02688698809001009

Fehlings, 1991, The association between polycystic kidney disease and cerebral aneurysms., 18, 505, 10.1017/S0317167100032248

Findlay, 1998, Causes of morbidity and mortality following intracranial aneurysm rupture., 25, 209, 10.1017/S031716710003403X

Fletcher, 1996

Fogelholm, 1987, Cigarette smoking and subarachnoid hemorrhage: a population-based case-control study., 50, 78, 10.1136/jnnp.50.1.78

Forbes, 1996, Interobserver variability in angiographic measurement and morphologic characterization of intracranial aneurysms: a report from the International Study of Unruptured Intracranial Aneurysms., 17, 1407

Forget, 2001, A review of size and location of ruptured intracranial aneurysms., 94, 175A

1983, 15

Freger, 1987, Faut-il operer les anevrysmes asymptomatiques? A propos de 114 anevrysmes asymptomatiques operes., 33, 462

Gabow, 1989, Pathophysiology of adult polycystic kidney disease., 18, 19

Gaetani, 1999, Metalloproteases and intracranial vascular lesions., 21, 385, 10.1080/01616412.1999.11740948

Graf, 1971, Prognosis for patients with nonsurgically-treated aneurysms. Analysis of the Cooperative Study of Intracranial Aneurysms and Subarachnoid hemorrhage., 35, 438, 10.3171/jns.1971.35.4.0438

Griffiths, 1996, Incidental intracranial vascular pathology in patients investigated for carotid stenosis., 38, 25, 10.1007/BF00593211

Hadeishi, 1991, [Risks of surgical treatment for unruptured intracranial aneurysms.], 19, 945

Hademenos, 1998, Anatomical and morphological factors correlating with rupture of intracranial aneurysms in patients referred for endovascular treatment., 40, 755, 10.1007/s002340050679

Hashimoto, 1983, The size of cerebral aneurysms in relation to repeated rupture., 19, 107, 10.1016/0090-3019(83)90404-4

Hayakawa, 2000, Natural history of the neck remnant of a cerebral aneurysm treated with the Guglielmi detachable coil system., 93, 561, 10.3171/jns.2000.93.4.0561

Heiskanen, 1981, Risk of bleeding from unruptured aneurysm in cases with multiple intracranial aneurysms., 55, 524, 10.3171/jns.1981.55.4.0524

Heiskanen, 1986, Risks of surgery for unruptured intracranial aneurysms., 65, 451, 10.3171/jns.1986.65.4.0451

Heiskanen, 1970, Risk of rupture of a second aneurysm in patients with multiple aneurysms., 32, 295, 10.3171/jns.1970.32.3.0295

Heiskanen, 1987, Surgery of incidental intracranial aneurysms., 28, 432, 10.1016/0090-3019(87)90225-4

Hillis, 2000, Cognitive impairments after surgical repair of ruptured and unruptured aneurysms., 69, 608, 10.1136/jnnp.69.5.608

Hodgson, 1998, Subarachnoid hemorrhage due to late recurrence of a previously unruptured aneurysm after complete endovascular occlusion., 19, 1939

Horikoshi, 2001, Prevalence of unruptured cerebral aneurysms in elderly patients., 94, 179A

Housepian, 1958, A systematic analysis of intracranial aneurysms from the autopsy file of the presbyterian hospital 1914 to 1956., 17, 409, 10.1097/00005072-195807000-00001

Hunt, 1968, Surgical risk as related to time of intervention in the repair of intracranial aneurysms., 28, 14, 10.3171/jns.1968.28.1.0014

Huston, 1994, Blinded prospective evaluation of sensitivity of MR angiography to known intracranial aneurysms: importance of aneurysms size., 15, 1607

Inagawa, 1991, Follow-up study of unruptured aneurysms arising from the C3 and C4 segments of the internal carotid artery., 36, 99, 10.1016/0090-3019(91)90225-X

Inagawa, 1990, Multiple intracranial aneurysms in elderly patients., 106, 119, 10.1007/BF01809453

Inagawa, 1991, Surgical treatment of multiple intracranial aneurysms., 108, 22, 10.1007/BF01407662

Inagawa, 1992, Unruptured intracranial aneurysms in elderly patients., 38, 364, 10.1016/0090-3019(92)90023-G

Inagawa, 1990, Autopsy study of unruptured incidental intracranial aneurysms., 34, 361, 10.1016/0090-3019(90)90237-J

Inagawa, 1990, Ruptured intracranial aneurysms: an autopsy study of 133 patients., 33, 117, 10.1016/0090-3019(90)90020-P

Inagawa, 1988, Aneurysmal subarachnoid hemorrhage in Izumo City and Shimane Prefecture of Japan, Incidence., 19, 170, 10.1161/01.STR.19.2.170

Inagawa, 2000, Primary intracerebral and aneurysmal subarachnoid hemorrhage in Izumo City, Japan. Part II: management and surgical outcome., 93, 967, 10.3171/jns.2000.93.6.0967

Inci, 2000, Intracranial aneurysms and arterial hypertension: a review and hypothesis., 53, 530, 10.1016/S0090-3019(00)00244-5

Ingall, 1989, Has there been a decline in subarachnoid hemorrhage mortality?, 20, 718, 10.1161/01.STR.20.6.718

1998, Unruptured intracranial aneurysms—risk of rupture and risks of surgical intervention., 339, 1725

Iwamoto, 1999, Prevalence of intracranial saccular aneurysms in a Japanese community based on a consecutive autopsy series during a 30-year observation period. The Hisayama study., 30, 1390, 10.1161/01.STR.30.7.1390

Jane, 1985, The natural history of aneurysms and arteriovenous malformations., 62, 321, 10.3171/jns.1985.62.3.0321

Johnston, 2000, Endovascular and surgical treatment of unruptured cerebral aneurysms: comparison of risks., 48, 11, 10.1002/1531-8249(200007)48:1<11::AID-ANA4>3.0.CO;2-V

Johnston, 1999, Surgical and endovascular treatment of unruptured cerebral aneurysms at university hospitals., 52, 1799, 10.1212/WNL.52.9.1799

Johnston, 1999, Which unruptured cerebral aneurysms should be treated? A cost-utility analysis., 52, 1806, 10.1212/WNL.52.9.1806

Johnston, 2001, Should we press for regionalization of surgery for unruptured cerebral aneurysms?, 94, 167A

Johnston, 2001, Treatment of unruptured cerebral aneurysms in California., 32, 597, 10.1161/01.STR.32.3.597

Johnston, 2001, Unruptured aneurysms treatment in California: surgery and endovascular therapy., 94, 188A

Juvela, 2000, Risk factors for multiple intracranial aneurysms., 31, 392, 10.1161/01.STR.31.2.392

Juvela, 1994, Natural history of unruptured aneurysms., 80, 773

Juvela, 1993, Natural history of unruptured intracranial aneurysms: a long-term follow-up study., 79, 174, 10.3171/jns.1993.79.2.0174

Juvela, 2000, Natural history of unruptured aneurysms: probability of and risk factors for aneurysm rupture., 93, 379, 10.3171/jns.2000.93.3.0379

Juvela, 2001, Factors affecting formation and growth of intracranial aneurysms: a long term follow-up study., 32, 485, 10.1161/01.STR.32.2.485

Kailasnath, 1998, A multiplicative statistical model predicts the size distribution of unruptured intracranial aneurysms., 20, 421, 10.1080/01616412.1998.11740542

Kamitani, 1999, Bleeding risk in unruptured and residual cerebral aneurysms—angiographic annual growth rate in nineteen patients., 141, 153, 10.1007/s007010050279

Kann, 1997, Safety of carotid endarterectomy associated with small intracranial aneurysms., 90, 1213, 10.1097/00007611-199712000-00010

Kappelle, 2000, Small, unruptured intracranial aneurysms and management of symptomatic carotid artery stenosis. North American Symptomatic Carotid Endarterectomy Trial Group., 55, 307, 10.1212/WNL.55.2.307

Kassell, 2001, Editorial comment: unruptured intracranial aneurysms: in search of the best management strategy., 32, 603

Kassell, 1984, The International Cooperative Study on Timing of Aneurysm Surgery—an update., 15, 566, 10.1161/01.STR.15.3.566

Kassell, 1983, Size of intracranial aneurysms., 12, 291, 10.1227/00006123-198303000-00007

Kataoka, 2000, Difference in nature of ruptured and unruptured cerebral aneurysms., 355, 203, 10.1016/S0140-6736(99)03881-7

Kataoka, 1999, Structural fragility and inflammatory response of ruptured cerebral aneurysms. A comparative study between ruptured and unruptured cerebral aneurysms., 30, 1396, 10.1161/01.STR.30.7.1396

King, 1994, Morbidity and mortality from elective surgery for asymptomatic, unruptured, intracranial aneurysms: a meta-analysis., 81, 837, 10.3171/jns.1994.81.6.0837

King, 1995, Elective surgery for asymptomatic, unruptured, intracranial aneurysms: a cost-effectiveness analysis., 83, 403, 10.3171/jns.1995.83.3.0403

Kiyohara, 1989, Incidence and prognosis of subarachnoid hemorrhage in a Japanese rural community., 20, 1150, 10.1161/01.STR.20.9.1150

Kobayashi, 1999, Treatment of unruptured cerebral aneurysms., 51, 355

Komatsu, 1994, [Surgical indication for unruptured cerebral aneurysm in patients with ischemic cerebrovascular disease.], 22, 811

Leblanc, 1995, Familial cerebral aneurysms: a study of 13 families., 37, 633, 10.1227/00006123-199510000-00005

Leblanc, 1995, Surgery of unruptured, asymptomatic aneurysms: a decision analysis., 22, 30, 10.1017/S0317167100040464

Leivo, 1996, Early surgery improves the cure of aneurysm-induced oculomotor palsy., 45, 430, 10.1016/0090-3019(95)00432-7

Linn, 1996, Incidence of subarachnoid hemorrhage: role of region, year, and rate of computed tomography: a meta-analysis., 27, 625, 10.1161/01.STR.27.4.625

Locksley, 1966, Natural history of subarachnoid hemorrhage, intracranial aneurysms and arteriovenous malformations., 25, 321, 10.3171/jns.1966.25.3.0321

Longstreth, 1992, Cigarette smoking, alcohol use, and subarachnoid hemorrhage., 23, 1242, 10.1161/01.STR.23.9.1242

Lozano, 1992, Cerebral aneurysms and polycystic kidney disease: a critical review., 19, 222, 10.1017/S031716710004230X

Magarisawa, 1994, [Review of cases of ruptured cerebral aneurysm with a history of examination at our institution prior to the diagnosis of subarachnoid hemorrhage—in order to improve treatment outcome in patients with intracranial aneurysms.], 46, 341

Mahoney, 1965, Functional evaluation: the Barthel Index., 14, 56

Malisch, 1997, Intracranial aneurysms treated with the Guglielmi detachable coil: midterm clinical results in a consecutive series of 100 patients., 87, 176, 10.3171/jns.1997.87.2.0176

Marshall, 2000, Effect of Guglielmi detachable coils on aneurysm management., 93, 719

Matsumoto, 1997, [Preoperative scoring and operative complications of unruptured cerebral aneurysms.], 25, 785

Mayer, 1996, Misdiagnosis of symptomatic cerebral aneurysm. Prevalence and correlation with outcome at four institutions., 27, 1558, 10.1161/01.STR.27.9.1558

McCormick, 1971, Problems and pathogenesis of intracranial arterial aneurysms, 219

McCormick, 1970, The size of intracranial saccular aneurysms. An autopsy study., 33, 422, 10.3171/jns.1970.33.4.0422

McCormick, 1965, Saccular intracranial aneurysms. An autopsy study., 22, 155, 10.3171/jns.1965.22.2.0155

McCormick, 1977, The relationship of arterial hypertension to intracranial aneurysms., 34, 285, 10.1001/archneur.1977.00500170039006

Meyer, 1995, Medical and surgical management of intracranial aneurysms., 70, 153, 10.4065/70.2.153

Mitchell, 2000, Risk analysis of treatment of unruptured aneurysms., 68, 577, 10.1136/jnnp.68.5.577

1979, Angiographical study of intracranial saccular aneurysms: with particular reference to their size and shape, 163

Mizoi, 1995, How to treat incidental cerebral aneurysms: a review of 139 consecutive cases., 44, 114, 10.1016/0090-3019(95)00035-6

Mount, 1974, Treatment of multiple aneurysms—symptomatic and asymptomatic., 21, 166, 10.1093/neurosurgery/21.CN_suppl_1.166

Mount, 1982, Treatment of multiple and asymptomatic intracranial aneurysms, 2, 765

Mount, 1971, Treatment of multiple intracranial aneurysms., 35, 728, 10.3171/jns.1971.35.6.0728

Murayama, 1999, Embolization of incidental cerebral aneurysms by using the Guglielmi detachable coil system., 90, 207, 10.3171/jns.1999.90.2.0207

Nakagawa, 1994, The incidence and treatment of asymptomatic, unruptured cerebral aneurysms., 80, 217, 10.3171/jns.1994.80.2.0217

Nakagawa, 1999, Family history of subarachnoid hemorrhage and the incidence of asymptomatic, unruptured cerebral aneurysms., 91, 391, 10.3171/jns.1999.91.3.0391

1982

1988

1994, 2

Nishimoto, 1985, Nationwide co-operative study of intracranial aneurysm surgery in Japan., 16, 48, 10.1161/01.STR.16.1.48

Ohno, 1999, Ischaemic complication following obliteration of unruptured cerebral aneurysms with atherosclerotic or calcified neck., 141, 699, 10.1007/s007010050364

Olafsson, 1997, A population-based study of prognosis of ruptured cerebral aneurysm: mortality and recurrence of subarachnoid hemorrhage., 48, 1191, 10.1212/WNL.48.5.1191

Orz, 2000, Risks of surgery for patients with unruptured intracranial aneurysms., 53, 21, 10.1016/S0090-3019(99)00171-8

Orz, 1997, Aneurysm size: a prognostic factor for rupture., 11, 144, 10.1080/02688699746500

Ostergaard Kristensen, 1983, Increased incidence of bleeding intracranial aneurysms in Greenlandic Eskimos., 67, 37, 10.1007/BF01401666

Pakarinen, 1967, Incidence, aetiology, and prognosis of primary subarachnoid haemorrhage. A study based on 589 cases diagnosed in a defined urban population in a defined period., 43, 1

Pappada, 1997, Incidence of asymptomatic berry aneurysms among patients undergoing carotid endarterectomy., 41, 257

Peebles Brown, 1951, Polycystic disease of the kidneys and intracranial aneurysms. The etiology and inter-relationship of these conditions: review of recent literature and report of seven cases in which both conditions coexisted., 32, 333

Peters, 2001, Molecular anatomy of an intracranial aneurysm: coordinated expression of genes involved in wound healing and tissue remodeling., 32, 1036, 10.1161/01.STR.32.4.1036

Phillips, 1980, The unchanging pattern of subarachnoid hemorrhage in a community., 30, 1034, 10.1212/WNL.30.10.1034

Piepgras, 1992, Clinical decision making in intracranial aneurysms and aneurysmal subarachnoid hemorrhage—science and art., 39, 68

Raaymakers, 2000, Functional outcome and quality of life after angiography and operation for unruptured intracranial aneurysms. On behalf of the MARS Study Group., 68, 571, 10.1136/jnnp.68.5.571

Raaymakers, 1998, Mortality and morbidity of surgery for unruptured intracranial aneurysms: a meta-analysis., 29, 1531, 10.1161/01.STR.29.8.1531

Rankin, 1957, Cerebral vascular accidents in patients over the age of 60. II. Prognosis., 2, 200, 10.1177/003693305700200504

Raps, 1993, The clinical spectrum of unruptured intracranial aneurysms., 50, 265, 10.1001/archneur.1993.00540030031010

Rice, 1990, Surgical treatment of unruptured aneurysms of the posterior circulation., 73, 165, 10.3171/jns.1990.73.2.0165

Richardson, 1941, Intracranial aneurysms. A clinical and pathological study of subarachnoid and intracerebral haemorrhage caused by berry aneurysms., 20, 1, 10.1097/00005792-194102000-00001

Rinkel, 1998, Prevalence and risk of rupture of intracranial aneurysms: a systematic review., 29, 251, 10.1161/01.STR.29.1.251

Rinne, 1996, Analysis of 561 patients with 690 middle cerebral artery aneurysms: anatomical and clinical features as correlated to management outcome., 38, 2, 10.1097/00006123-199601000-00002

Rinne, 1995, Management outcome for multiple intracranial aneurysms., 36, 31, 10.1227/00006123-199501000-00003

Rogers, 1987, Intracranial aneurysm size and potential for rupture., 67, 475

Romy, 1973, De la fréquence des anévrismes artériels intra-crâniens et de leur rupture, d'apres une serie d'autopsies de routine., 19, 611

Ronkainen, 1997, Familial intracranial aneurysms., 349, 380, 10.1016/S0140-6736(97)80009-8

Ronkainen, 1993, Familial subarachnoid hemorrhage in east Finland, 1977–1990., 33, 787

Ronkainen, 1994, A ten percent prevalence of asymptomatic familial intracranial aneurysms: preliminary report on 110 magnetic resonance angiography studies in members of 21 Finnish familial intracranial aneurysm families., 35, 208, 10.1227/00006123-199408000-00005

Ronkainen, 1995, Special features of familial intracranial aneurysms: report of 215 familial aneurysms., 37, 43, 10.1227/00006123-199507000-00006

Ronkainen, 1998, Risk of harboring an unruptured intracranial aneurysm., 29, 359, 10.1161/01.STR.29.2.359

Ronkainen, 1995, Intracranial aneurysms: MR angiographic screening in 400 asymptomatic individuals with increased familial risk., 195, 35, 10.1148/radiology.195.1.7892491

Rosenorn, 1993, Does a safe size-limit exist for unruptured intracranial aneurysms?, 121, 113, 10.1007/BF01809260

Rosenorn, 1994, Patients with ruptured intracranial saccular aneurysms: clinical features and outcome according to the size., 8, 73, 10.3109/02688699409002396

Rosenørn, 2001, Has life expectancy in persons with unruptured intracranial aneurysms changed after new publications concerning the risk of rupture?, 94, 162A

Rosenorn, 1988, Unruptured intracranial aneurysms: an assessment of the annual risk of rupture based on epidemiological and clinical data., 2, 369, 10.3109/02688698809001008

Sacco, 1984, Subarachnoid and intracerebral hemorrhage: natural history, prognosis, and precursive factors in the Framington Study., 34, 847, 10.1212/WNL.34.7.847

Samejima, 1990, New screening system for unruptured cerebral aneurysms—combination of an expert system and DS angiography examination., 30, 575, 10.2176/nmc.30.575

Sampei, 1991, [Clinical study of growing up aneurysms: report of 25 cases.], 19, 825

Samson, 1977, Surgical management of unruptured asymptomatic aneurysms., 46, 731, 10.3171/jns.1977.46.6.0731

Sarti, 1991, Epidemiology of subarachnoid hemorrhage in Finland from 1983 to 1985., 22, 848, 10.1161/01.STR.22.7.848

Sarwar, 1976, Growing intracranial aneurysms., 120, 603, 10.1148/120.3.603

Saveland, 1994, Which are the major determinants for outcome in aneurysmal subarachnoid hemorrhage? A prospective total management study from a strictly unselected series., 90, 245

Saveland, 1993, Causes of morbidity and mortality, with special reference to surgical complications, after early aneurysm operation: a prospective, one-year study from neurosurgical units in Sweden., 88, 254

Schievink, 1992, Rupture of previously documented small asymptomatic saccular intracranial aneurysms. Report of three cases., 76, 1019, 10.3171/jns.1992.76.6.1019

Schievink, 1992, Saccular intracranial aneurysms in autosomal dominant polycystic kidney disease., 3, 88, 10.1681/ASN.V3188

Schreiber, 1977, Rupturierte Hirnbasis aneurysmen. Eine Analyse des Obduktionsqutes aus 2 pathologischen Instituten., 121, 11

Sekhar, 1981, Origin, growth, and rupture of saccular aneurysms: a review., 8, 248, 10.1227/00006123-198102000-00020

Solomon, 1988, Rupture of a previously documented asymptomatic aneurysm enhances the argument for prophylactic surgical intervention., 30, 321, 10.1016/0090-3019(88)90307-2

Solomon, 1994, Surgical management of unruptured intracranial aneurysms., 80, 440, 10.3171/jns.1994.80.3.0440

Solomon, 1996, Relationship between the volume of craniotomies for cerebral aneurysm performed in New York state hospitals and in-hospital mortality., 27, 13, 10.1161/01.STR.27.1.13

Stehbens, 1963, Aneurysmal and anatomical variation of cerebral arteries., 75, 45

Stehbens, 1972, 351

Suzuki, 1978, Clinicopathological study of cerebral aneurysms. Origin, rupture, repair, and growth., 48, 505, 10.3171/jns.1978.48.4.0505

Taylor, 1995, Cerebral arterial aneurysm formation and rupture in 20,767 elderly patients: hypertension and other risk factors., 83, 812, 10.3171/jns.1995.83.5.0812

Taylor, 1997, Mortality rates, hospital length of stay, and the cost of treating subarachnoid hemorrhage in older patients: institutional and geographical differences., 86, 583, 10.3171/jns.1997.86.4.0583

ter Berg, 1988, Treatment of intact familial intracranial aneurysms: a decision-analytical approach., 23, 329, 10.1227/00006123-198809000-00007

Teunissen, 1996, Risk factors for subarachnoid hemorrhage: a systematic review., 27, 544, 10.1161/01.STR.27.3.544

Torres, 1990, Cranial computed tomography and magnetic resonance imaging in autosomal dominant polycystic kidney disease., 1, 84

Truelsen, 1998, Changes in subarachnoid hemorrhage mortality, incidence, and case fatality in New Zealand between 1981–1983 and 1991–1993., 29, 2298, 10.1161/01.STR.29.11.2298

Tsutsumi, 2000, Risk of rupture from incidental cerebral aneurysms., 93, 550, 10.3171/jns.2000.93.4.0550

Tsutsumi, 1999, Risk of subarachnoid hemorrhage after surgical treatment of unruptured cerebral aneurysms., 30, 1181, 10.1161/01.STR.30.6.1181

Ujiie, 1993, Clinical analysis of incidentally discovered unruptured aneurysms., 24, 1850, 10.1161/01.STR.24.12.1850

Ujiie, 1999, Effect of size and shape (aspect ratio) on the hemodynamics of saccular aneurysms: a possible index for surgical treatment of intracranial aneurysms., 45, 119

Ujiie, 2001, Is the aspect ratio a reliable index for predicting the rupture of a saccular aneurysm?, 48, 495, 10.1097/00006123-200103000-00007

van Crevel, 1986, Decision analysis of the management of incidental intracranial saccular aneurysms., 36, 1335, 10.1212/WNL.36.10.1335

Vanninen, 1996, Magnetic resonance angiographic screening for asymptomatic intracranial aneurysms: the problem of false negatives: technical case report., 38, 840

Vilkki, 1990, Social outcome related to cognitive performance and computed tomographic findings after surgery for a ruptured intracranial aneurysm., 26, 579, 10.1227/00006123-199004000-00004

Wakabayashi, 1983, Polycystic kidney disease and intracranial aneurysms. Early angiographic diagnosis and early operation for the unruptured aneurysm., 58, 488, 10.3171/jns.1983.58.4.0488

Wardlaw, 2000, The detection and management of unruptured intracranial aneurysms., 123, 205, 10.1093/brain/123.2.205

Weir, 1987, 226

Weir, 1998, 26

Weir, 2002, Sizes of ruptured and unruptured aneurysms in relation to their sites and the ages of patients., 96, 64, 10.3171/jns.2002.96.1.0064

Weir, 1998, Cigarette smoking as a cause of aneurysmal subarachnoid hemorrhage and risk for vasospasm: a report of the Cooperative Aneurysm Study., 89, 405, 10.3171/jns.1998.89.3.0405

Wiebers, 1992, Impact of unruptured intracranial aneurysms on public health in the United States., 23, 1416, 10.1161/01.STR.23.10.1416

Wiebers, 1990, Rupture of an intracranial aneurysm., 33, 157

Wiebers, 1981, The natural history of unruptured intracranial aneurysms., 304, 696, 10.1056/NEJM198103193041203

Wiebers, 1987, The significance of unruptured intracranial saccular aneurysms., 66, 23, 10.3171/jns.1987.66.1.0023

Winn, 1983, The long-term outcome in patients with multiple aneurysms. Incidence of late hemorrhage and implications for treatment of incidental aneurysms., 59, 642, 10.3171/jns.1983.59.4.0642

Winn, 1981, Long-term evaluation of patients with multiple cerebral aneurysms., 10, 106

Wirth, 1983, Surgical treatment of incidental intracranial aneurysms., 12, 507, 10.1227/00006123-198305000-00005

Wong, 2001, Safety of endovascular coil placement in unruptured cerebral aneurysms: a 10-year experience., 94, 187A

Yasui, 1997, Long-term followup of unruptured intracranial aneurysms., 40, 1155, 10.1097/00006123-199706000-00007

Yasui, 1998, [Management of elderly patients with incidentally discovered unruptured aneurysms.], 26, 679

Yoshimoto, 1997, Importance of management of unruptured cerebral aneurysms., 47, 522, 10.1016/S0090-3019(96)00400-4

Yoshimoto, 1999, Cost-effectiveness analysis of screening for asymptomatic, unruptured intracranial aneurysms. A mathematical model., 30, 1621, 10.1161/01.STR.30.8.1621

Zacks, 1980, Fortuitously discovered intracranial aneurysms., 37, 39, 10.1001/archneur.1980.00500500069010