Cerebral Aneurysms Treatment & Management
- Author: David S Liebeskind, MD; Chief Editor: Helmi L Lutsep, MD more...
Prehospital care should include assessment of vital signs and neurological status. Airway, breathing, and circulation should be addressed with endotracheal intubation, if necessary, and establishment of intravenous access.
Medical therapy of cerebral aneurysms involves general supportive measures and prevention of complications for individuals who are in the periprocedural period or are poor surgical candidates. Treatment decisions should be based on the clinical status of the patient, vascular anatomy of the aneurysm, and surgical or endovascular considerations.
Medical management of aneurysmal SAH is orchestrated in the ICU, with cardiac monitoring and placement of an arterial line.
Prior to definitive aneurysm treatment, medical approaches involve control of hypertension, administration of calcium channel blockers, and prevention of seizures.
Following surgical or endovascular aneurysm treatment, blood pressure is maintained at higher levels to diminish complications associated with vasospasm. Vasospasm usually occurs between days 3 and 21, presenting with headache, decreased level of consciousness, and variable neurological deficits. Serial TCD may be employed to detect trends in cerebral blood flow during this period.
Induced hypertension, hypervolemia, and hemodilution (ie, "triple-H therapy") aims to maintain adequate cerebral perfusion pressure in the setting of impaired cerebrovascular autoregulation.
Intraarterial papaverine or endovascular balloon angioplasty may be used to treat vasospasm in select patients.
Infectious aneurysms are friable, with an increased propensity for hemorrhage. Anticoagulation is avoided in this setting. As these lesions resolve with antibiotic therapy, surgical approaches usually are deferred. Regression or evolution of these aneurysms is monitored with serial angiography.
Unruptured Intracranial Aneurysms
The management of unruptured intracranial aneurysms is highly controversial. The International Study of Unruptured Intracranial Aneurysms (ISUIA) indicated a relatively low risk of rupture in small aneurysms without history of SAH. Aneurysms less than 10 mm in size had an annual rupture rate of approximately 0.05%. For posterior communicating, vertebrobasilar/posterior cerebral, or basilar tip aneurysms less than 10 mm, the risk of rupture over 7.5 years approximated 2%, with all other locations harboring a risk of almost 0%. Recent guidelines and an evidence-based systematic review of the literature have formulated recommendations for the care of patients with unruptured intracranial aneurysms, principally based on age, history, and aneurysm size.
The anatomical characterization and morphology of unruptured aneurysms are not readily standardized, however. Some investigators have advocated endovascular or surgical treatment of all aneurysms less than 10 mm if age is less than 50 years, in the absence of contraindications. The presence of cigarette smoking, family history of aneurysms, polycystic kidney disease, or systemic lupus erythematosus may elevate the risk of rupture and should be considered. Asymptomatic aneurysms greater than 10 mm should also be considered for treatment, accounting for age, coexisting medical conditions, and relative risks for treatment.
Considerable surgical mortality and morbidity rates at 1 year (as high as 3.8% and 15.7%, respectively) have been demonstrated in preventive treatment of unruptured aneurysms. The surgeon's experience may be a significant and highly variable factor in operative morbidity rate and functional outcome. More recently, application of diffusion-weighted MRI has demonstrated silent thromboembolic events associated with endovascular treatment of unruptured cerebral aneurysms. Quality-of-life issues, including the psychological morbidity of living with an unruptured intracranial aneurysm, also must be addressed.
Therapeutic decision making must balance endovascular or surgical morbidity and mortality rates with the risk of hemorrhage and other considerations on an individual basis. Future studies in the management of unruptured intracranial aneurysms may systematically account for the evolving technology of advanced endovascular approaches, detailed aneurysm morphology, novel neuroimaging correlates, ethnic and geographical variation, neurocognitive impairment following endovascular or surgical treatment, and quality-of-life issues.
Microsurgical techniques focus on excluding the aneurysm from the cerebral circulation and reducing mass effects on adjacent structures. Various approaches have been developed and tailored to the anatomy and location of the aneurysm. A surgical clip usually is placed across the aneurysm neck with preservation of the parent vessel, eliminating any aneurysmal rests that may redevelop subsequently. Alternative techniques involve proximal or Hunterian ligation, wrapping the aneurysm, and trapping (ie, combined proximal and distal vessel occlusion).
Adjunctive measures have been developed to reduce operative morbidity and to provide cerebral protection. Aneurysmal rupture, the principal surgical complication, may be avoided with induced hypotension, CSF drainage, diuretics, hyperventilation, and use of minimal brain retraction. Hypothermia, with or without circulatory arrest, and systemic hypotension are used commonly. A large study of mild intraoperative hypothermia, however, failed to demonstrate benefit of this adjunctive technique.
Lumbar spinal drainage allows relaxation of brain parenchyma and provides a clean surgical field. Postoperative angiography is performed routinely to check for major vessel occlusion or persistence of an aneurysmal rest. Operative morbidity rate increases with aneurysm size (2.3% for < 5 mm; 6.8% for 6-15 mm, 14% for 16-25 mm) and varies by location.
Optimal timing of aneurysm surgery depends on the clinical status of the patient and associated factors. Early surgery (ie, < 48-96 hours after SAH) is favored for candidates in good condition or those with unstable blood pressure, seizures, mass effect from thrombus, large amounts of blood, or evidence of aneurysm growth or rebleeding. Early surgery carries an increased operative morbidity, although the risks of vasospasm and rebleeding are reduced considerably.
Delayed surgery (ie, 10-14 d after SAH) may be considered for large aneurysms in difficult locations or for candidates in poor clinical condition. Surgery is indicated for ruptured or symptomatic aneurysms in patients without extenuating contraindications or considerably advanced age. Surgery generally is precluded if the clinical status is poor, corresponding to Hunt and Hess grade 4 or 5.
Advances in endovascular techniques have provided therapeutic alternatives that may be employed even in the setting of acute aneurysmal SAH. These techniques allow parent vessel preservation and may be combined with surgical approaches. Electrolytically detachable platinum coils (eg, Guglielmi detachable coils [GDC]) may be deployed strategically within the aneurysm, promoting thrombosis and eventual obliteration. Wide-neck aneurysms may be more difficult to occlude with these devices. Other materials, such as balloons or glue, also may be used. Complications include vessel perforation, hemorrhage, or distal thromboembolism.
Endovascular therapy or coiling of cerebral aneurysms has proliferated during the past of particular cerebral aneurysms are likely influenced by numerous factors. The International Subarachnoid Aneurysm Trial (ISAT) demonstrated the superiority of coiling with improved clinical outcomes. Seizures were also less common in patients with endovascular treatment, yet late rebleeding was also more common. Selection bias may also have influenced ISAT and, therefore, treatment for a given individual must still be tailored to each case.
A meta-analysis of relevant studies (including ISAT) found that endovascular coiling of cerebral aneurysms yields a better clinical outcome than clipping does, with the benefit greatest in patients with a good preoperative grade.[3, 4] The analysis also confirmed, however, that there is a greater risk of rebleeding with coiling, particularly for patients with a poor preoperative grade. Patient mortality at 1 year with coiling was not significantly different from 1-year mortality with clipping.[3, 4]
Progressive refinement in endovascular techniques and devices tailored for the cerebrovasculature have expanded therapeutic options available for definitive treatment of cerebral aneurysms. More pliable, low-profile stents may be used for stent-assisted coiling for obliteration of wide-necked aneurysms.
Self-expanding or balloon-expandable covered stents may be used for treatment of selected carotid or vertebral artery pseudoaneurysms. The Silk flow-diverter stent allows complete occlusion in most cases after 1 year of treatment, with 7.8% permanent morbidity and 3% mortality.
Large or giant intracranial aneurysms may be treated with a combination of devices, such as stent-assisted coil placement. However, the requirement of dual antiplatelet therapy in stent-assisted coiling may increase the risk of intracranial hemorrhage.
Refinement of endovascular techniques for very small intracranial aneurysms has expanded treatment options, yet complications may also increase in this particular subset.
Although endovascular coiling is a feasible, effective treatment for many elderly patients with ruptured and unruptured intracranial aneurysms, careful patient selection is crucial in view of the risks of the procedure, which may outweigh the risk of rupture in some patients with unruptured aneurysms, according to a systematic review and meta-analysis that included 21 studies of 1511 patients aged 65 years or older.[14, 15]
In this study, long-term occlusion was achieved in 79% of patients. The rate of perioperative stroke (4%) was similar for patients with unruptured and ruptured aneurysms. Intraprocedural rupture occurred in 1% of patients with unruptured aneurysms and in 4% of patients with ruptured aneurysms. Perioperative mortality was 23% for patients with ruptured aneurysms and 1% for those with unruptured aneurysms. At 1-year follow-up, 93% of patients with unruptured aneurysms and 66% of patients with ruptured aneurysms had good outcomes.
A multidisciplinary approach to the treatment of cerebral aneurysms is recommended. The following specialists should be a part of the multidisciplinary team:
Restrict possible surgical candidates to taking nothing by mouth (NPO).
Employ nasogastric feedings for individuals with a decreased level of consciousness.
Recommend a soft, high-fiber diet to alert patients; patients should avoid caffeine.
Advise bed rest in a quiet dark environment during the initial week following aneurysmal SAH.
Perform passive range of motion exercises and frequent turning.
Assist patients with self-care activities, followed by slow advancement in activity as tolerated.
Brooks M. Serial Screening for Cerebral Aneurysm Fruitful. Medscape Medical News. Available at http://www.medscape.com/viewarticle/824618. Accessed: May 14, 2014.
Bor AS, Rinkel GJ, van Norden J, Wermer MJ. Long-term, serial screening for intracranial aneurysms in individuals with a family history of aneurysmal subarachnoid haemorrhage: a cohort study. Lancet Neurol. 2014 Apr. 13(4):385-92. [Medline].
Brooks M. Does Coiling Beat Clipping for Ruptured Aneurysms? Medscape Medical News. Dec 31 2012. Available at http://www.medscape.com/viewarticle/776939. Accessed: Jan 16, 2013.
Li H, Pan R, Wang H, Rong X, Yin Z, Milgrom DP, et al. Clipping versus coiling for ruptured intracranial aneurysms: a systematic review and meta-analysis. Stroke. 2013 Jan. 44(1):29-37. [Medline].
Koroknay-Pál P, Laakso A, Lehto H, Seppä K, Kivisaari R, Hernesniemi J, et al. Long-term Excess Mortality in Pediatric Patients With Cerebral Aneurysms. Stroke. 2012 Aug. 43(8):2091-6. [Medline].
Vernooij MW, Ikram MA, Tanghe HL, Vincent AJ, Hofman A, Krestin GP, et al. Incidental findings on brain MRI in the general population. N Engl J Med. 2007 Nov 1. 357(18):1821-8. [Medline].
Yang CY, Chen YF, Lee CW, Huang A, Shen Y, Wei C, et al. Multiphase CT angiography versus single-phase CT angiography: comparison of image quality and radiation dose. AJNR Am J Neuroradiol. 2008 Aug. 29(7):1288-95. [Medline].
van Rooij WJ, Sprengers ME, de Gast AN, Peluso JP, Sluzewski M. 3D rotational angiography: the new gold standard in the detection of additional intracranial aneurysms. AJNR Am J Neuroradiol. 2008 May. 29(5):976-9. [Medline].
Yi AC, Palmer E, Luh GY, Jacobson JP, Smith DC. Endovascular treatment of carotid and vertebral pseudoaneurysms with covered stents. AJNR Am J Neuroradiol. 2008 May. 29(5):983-7. [Medline].
Berge J, Biondi A, Machi P, Brunel H, Pierot L, Gabrillargues J, et al. Flow-Diverter Silk Stent for the Treatment of Intracranial Aneurysms: 1-year Follow-Up in a Multicenter Study. AJNR Am J Neuroradiol. 2012 Feb 2. [Medline].
Yang X, Wu Z, Mu S, Li Y, Lv M. Endovascular treatment of giant and large intracranial aneurysms using the neuroform stent-assisted coil placement. Neurol Res. 2008 Jul. 30(6):598-602. [Medline].
Tumialán LM, Zhang YJ, Cawley CM, Dion JE, Tong FC, Barrow DL. Intracranial hemorrhage associated with stent-assisted coil embolization of cerebral aneurysms: a cautionary report. J Neurosurg. 2008 Jun. 108(6):1122-9. [Medline].
Nguyen TN, Raymond J, Guilbert F, Roy D, Bérubé MD, Mahmoud M, et al. Association of endovascular therapy of very small ruptured aneurysms with higher rates of procedure-related rupture. J Neurosurg. 2008 Jun. 108(6):1088-92. [Medline].
Harding A. Careful selection key to coiling in elderly aneurysm patients. Medscape Medical News. May 23, 2013. [Full Text].
Sturiale CL, Brinjikji W, Murad MH, Lanzino G. Endovascular Treatment of Intracranial Aneurysms in Elderly Patients: A Systematic Review and Meta-Analysis. Stroke. 2013 May 16. [Medline].
Anzalone N, Scomazzoni F, Cirillo M, Righi C, Simionato F, Cadioli M, et al. Follow-up of coiled cerebral aneurysms at 3T: comparison of 3D time-of-flight MR angiography and contrast-enhanced MR angiography. AJNR Am J Neuroradiol. 2008 Sep. 29(8):1530-6. [Medline].
Adams WM, Laitt RD, Jackson A. The role of MR angiography in the pretreatment assessment of intracranial aneurysms: a comparative study. AJNR Am J Neuroradiol. 2000 Oct. 21(9):1618-28. [Medline].
Alg VS, Sofat R, Houlden H, Werring DJ. Genetic risk factors for intracranial aneurysms: A meta-analysis in more than 116,000 individuals. Neurology. 2013 Jun 4. 80(23):2154-65. [Medline].
Andaluz N, Zuccarello M. Recent trends in the treatment of cerebral aneurysms: analysis of a nationwide inpatient database. J Neurosurg. 2008 Jun. 108(6):1163-9. [Medline].
Anson JA, Lawton MT, Spetzler RF. Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms. J Neurosurg. 1996 Feb. 84(2):185-93. [Medline].
Aoki N, Beck JR, Kitahara T. Reanalysis of unruptured intracranial aneurysm management: effect of a new international study on the threshold probabilities. Med Decis Making. 2001 Mar-Apr. 21(2):87-96. [Medline].
Becker KJ. Epidemiology and clinical presentation of aneurysmal subarachnoid hemorrhage. Neurosurg Clin N Am. 1998 Jul. 9(3):435-44. [Medline].
Bederson JB, Awad IA, Wiebers DO. Recommendations for the management of patients with unruptured intracranial aneurysms: A Statement for healthcare professionals from the Stroke Council of the American Heart Association. Stroke. 2000 Nov. 31(11):2742-50. [Medline].
Benndorf G, Klucznik RP, Meyer D. "Cross-over" technique for horizontal stenting of an internal carotid bifurcation aneurysm using a new self-expandable stent: technical case report. Neurosurgery. 2006 Feb. 58(1 Suppl):ONS-E172. [Medline].
Brennan JW, Schwartz ML. Unruptured intracranial aneurysms: appraisal of the literature and suggested recommendations for surgery, using evidence-based medicine criteria. Neurosurgery. 2000 Dec. 47(6):1359-71; discussion 1371-2. [Medline].
Brilstra EH, Rinkel GJ, van der Graaf Y. Treatment of intracranial aneurysms by embolization with coils: a systematic review. Stroke. 1999 Feb. 30(2):470-6. [Medline].
Broderick JP. Coiling, clipping, or medical management of unruptured intracranial aneurysms: time to randomize?. Ann Neurol. 2000 Jul. 48(1):5-6. [Medline].
Campi A, Ramzi N, Molyneux AJ, Summers PE, Kerr RS, Sneade M, et al. Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT). Stroke. 2007 May. 38(5):1538-44. [Medline].
Carter BS, Sheth S, Chang E. Epidemiology of the size distribution of intracranial bifurcation aneurysms: smaller size of distal aneurysms and increasing size of unruptured aneurysms with age. Neurosurgery. 2006 Feb. 58(2):217-23; discussion 217-23. [Medline].
Chyatte D, Fode NC, Sundt TM. Early versus late intracranial aneurysm surgery in subarachnoid hemorrhage. J Neurosurg. 1988 Sep. 69(3):326-31. [Medline].
Chyatte D, Porterfield R. Functional outcome after repair of unruptured intracranial aneurysms. J Neurosurg. 2001 Mar. 94(3):417-21. [Medline].
Connolly ES, Mohr JP, Solomon RA. Unruptured intracranial aneurysms. N Engl J Med. 1999 May 6. 340(18):1440-1; discussion 1441-2. [Medline].
de Oliveira JG, Beck J, Ulrich C, Rathert J, Raabe A, Seifert V. Comparison between clipping and coiling on the incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis. Neurosurg Rev. 2007 Jan. 30(1):22-30; discussion 30-1. [Medline].
Donnan GA, Davis SM. Patients with small, asymptomatic, unruptured intracranial aneurysms and no history of subarachnoid hemorrhage should be treated conservatively. Stroke. 2005 Feb. 36(2):407. [Medline].
Gonzalez N, Murayama Y, Nien YL. Treatment of unruptured aneurysms with GDCs: clinical experience with 247 aneurysms. AJNR Am J Neuroradiol. 2004 Apr. 25(4):577-83. [Medline].
Haley EC, Kassell NF, Torner JC. The International Cooperative Study on the Timing of Aneurysm Surgery. The North American experience. Stroke. 1992 Feb. 23(2):205-14. [Medline].
Hashimoto H, Iida J, Hironaka Y. Use of spiral computerized tomography angiography in patients with subarachnoid hemorrhage in whom subtraction angiography did not reveal cerebral aneurysms. J Neurosurg. 2000 Feb. 92(2):278-83. [Medline].
Johnston SC, Dowd CF, Higashida RT, Lawton MT, Duckwiler GR, Gress DR. Predictors of rehemorrhage after treatment of ruptured intracranial aneurysms: the Cerebral Aneurysm Rerupture After Treatment (CARAT) study. Stroke. 2008 Jan. 39(1):120-5. [Medline].
Johnston SC, Wilson CB, Halbach VV. Endovascular and surgical treatment of unruptured cerebral aneurysms: comparison of risks. Ann Neurol. 2000 Jul. 48(1):11-9. [Medline].
Johnston SC, Zhao S, Dudley RA. Treatment of unruptured cerebral aneurysms in California. Stroke. 2001 Mar. 32(3):597-605. [Medline].
Juvela S. Recommendations for the management of patients with unruptured intracranial aneurysms. Stroke. 2001 Mar. 32(3):815-6. [Medline].
Juvela S, Poussa K, Porras M. Factors affecting formation and growth of intracranial aneurysms: a long-term follow-up study. Stroke. 2001 Feb. 32(2):485-91. [Medline].
Karmonik C, Strother CM, Chen X. Stent-assisted coiling of intracranial aneurysms aided by virtual parent artery reconstruction. AJNR Am J Neuroradiol. 2005 Oct. 26(9):2368-70. [Medline].
Kim DH, Haney CL, Van Ginhoven G. Utility of outcome measures after treatment for intracranial aneurysms: a prospective trial involving 520 patients. Stroke. 2005 Apr. 36(4):792-6. [Medline].
Kurre W, Berkefeld J. Materials and techniques for coiling of cerebral aneurysms: how much scientific evidence do we have?. Neuroradiology. 2008 Nov. 50(11):909-27. [Medline].
Lavine SD, Meyers PM. Application of new techniques and technologies: stenting for cerebral aneurysm. Clin Neurosurg. 2007. 54:64-9. [Medline].
Le Roux PD, Winn HR. Management of the ruptured aneurysm. Neurosurg Clin N Am. 1998 Jul. 9(3):525-40. [Medline].
Lylyk P, Ferrario A, Pasbon B. Buenos Aires experience with the Neuroform self-expanding stent for the treatment of intracranial aneurysms. J Neurosurg. 2005 Feb. 102(2):235-41. [Medline].
Mayberg MR. Cerebral vasospasm. Neurosurg Clin N Am. 1998 Jul. 9(3):615-27. [Medline].
McKinney AM, Palmer CS, Truwit CL, Karagulle A, Teksam M. Detection of aneurysms by 64-section multidetector CT angiography in patients acutely suspected of having an intracranial aneurysm and comparison with digital subtraction and 3D rotational angiography. AJNR Am J Neuroradiol. 2008 Mar. 29(3):594-602. [Medline].
Mitchell P, Kerr R, Mendelow AD, Molyneux A. Could late rebleeding overturn the superiority of cranial aneurysm coil embolization over clip ligation seen in the International Subarachnoid Aneurysm Trial?. J Neurosurg. 2008 Mar. 108(3):437-42. [Medline].
Molyneux A, Kerr R, Stratton I. International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised trial. Lancet. 2002 Oct 26. 360(9342):1267-74. [Medline].
Molyneux AJ, Cekirge S, Saatci I. Cerebral Aneurysm Multicenter European Onyx (CAMEO) trial: results of a prospective observational study in 20 European centers. AJNR Am J Neuroradiol. 2004 Jan. 25(1):39-51. [Medline].
Molyneux AJ, Kerr RS, Yu LM. International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, a. Lancet. 2005 Sep 3-9. 366(9488):809-17. [Medline].
Niimi Y, Song J, Madrid M. Endosaccular treatment of intracranial aneurysms using matrix coils: early experience and midterm follow-up. Stroke. 2006 Apr. 37(4):1028-32. [Medline].
Parra A, Kreiter KT, Williams S. Effect of prior statin use on functional outcome and delayed vasospasm after acute aneurysmal subarachnoid hemorrhage: a matched controlled cohort study. Neurosurgery. 2005 Mar. 56(3):476-84; discussion 476-84. [Medline].
Pierot L, Spelle L, Vitry F. Immediate clinical outcome of patients harboring unruptured intracranial aneurysms treated by endovascular approach: results of the ATENA study. Stroke. 2008 Sep. 39(9):2497-504. [Medline].
Pluta RM, Dejam A, Grimes G. Nitrite infusions to prevent delayed cerebral vasospasm in a primate model of subarachnoid hemorrhage. JAMA. 2005 Mar 23. 293(12):1477-84. [Medline].
Qureshi AI, Mohammad Y, Yahia AM. Ischemic events associated with unruptured intracranial aneurysms: multicenter clinical study and review of the literature. Neurosurgery. 2000 Feb. 46(2):282-9; discussion 289-90. [Medline].
Raaymakers TW, Buys PC, Verbeeten B. MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement. AJR Am J Roentgenol. 1999 Dec. 173(6):1469-75. [Medline].
Reeves BC, Langham J, Lindsay KW, Molyneux AJ, Browne JP, Copley L, et al. Findings of the International Subarachnoid Aneurysm Trial and the National Study of Subarachnoid Haemorrhage in context. Br J Neurosurg. 2007 Aug. 21(4):318-23; discussion 323-7. [Medline].
Rinkel GJ. Medical management of patients with aneurysmal subarachnoid haemorrhage. Int J Stroke. 2008 Aug. 3(3):193-204. [Medline].
Rordorf G, Bellon RJ, Budzik RE Jr. Silent thromboembolic events associated with the treatment of unruptured cerebral aneurysms by use of Guglielmi detachable coils: prospective study applying diffusion-weighted imaging. AJNR Am J Neuroradiol. 2001 Jan. 22(1):5-10. [Medline].
Rosen DS, Macdonald RL. Subarachnoid hemorrhage grading scales: a systematic review. Neurocrit Care. 2005. 2(2):110-8. [Medline].
Ryttlefors M, Enblad P, Kerr RS, Molyneux AJ. International subarachnoid aneurysm trial of neurosurgical clipping versus endovascular coiling: subgroup analysis of 278 elderly patients. Stroke. 2008 Oct. 39(10):2720-6. [Medline].
Salary M, Quigley MR, Wilberger JE Jr. Relation among aneurysm size, amount of subarachnoid blood, and clinical outcome. J Neurosurg. 2007 Jul. 107(1):13-7. [Medline].
Sanai N, Tarapore P, Lee AC, Lawton MT. The current role of microsurgery for posterior circulation aneurysms: a selective approach in the endovascular era. Neurosurgery. 2008 Jun. 62(6):1236-49; discussion 1249-53. [Medline].
Schievink WI. Genetics and aneurysm formation. Neurosurg Clin N Am. 1998 Jul. 9(3):485-95. [Medline].
Schmid-Elsaesser R, Kunz M, Zausinger S, Prueckner S, Briegel J, Steiger HJ. Intravenous magnesium versus nimodipine in the treatment of patients with aneurysmal subarachnoid hemorrhage: a randomized study. Neurosurgery. 2006 Jun. 58(6):1054-65; discussion 1054-65. [Medline].
Sherlock M, O'sullivan E, Agha A. The incidence and pathophysiology of hyponatraemia after subarachnoid haemorrhage. Clin Endocrinol (Oxf). 2006 Mar. 64(3):250-4. [Medline].
Sluzewski M, van Rooij WJ. Early rebleeding after coiling of ruptured cerebral aneurysms: incidence, morbidity, and risk factors. AJNR Am J Neuroradiol. 2005 Aug. 26(7):1739-43. [Medline].
Sluzewski M, van Rooij WJ, Beute GN. Late rebleeding of ruptured intracranial aneurysms treated with detachable coils. AJNR Am J Neuroradiol. 2005 Nov-Dec. 26(10):2542-9. [Medline].
Solenski NJ, Haley EC, Kassell NF. Medical complications of aneurysmal subarachnoid hemorrhage: a report of the multicenter, cooperative aneurysm study. Participants of the Multicenter Cooperative Aneurysm Study. Crit Care Med. 1995 Jun. 23(6):1007-17. [Medline].
Solomon RA, Fink ME, Pile-Spellman J. Surgical management of unruptured intracranial aneurysms. J Neurosurg. 1994 Mar. 80(3):440-6. [Medline].
Standhardt H, Boecher-Schwarz H, Gruber A, Benesch T, Knosp E, Bavinzski G. Endovascular treatment of unruptured intracranial aneurysms with Guglielmi detachable coils: short- and long-term results of a single-centre series. Stroke. 2008 Mar. 39(3):899-904. [Medline].
Todd MM, Hindman BJ, Clarke WR. Mild intraoperative hypothermia during surgery for intracranial aneurysm. N Engl J Med. 2005 Jan 13. 352(2):135-45. [Medline].
van den Bergh WM, Algra A, van Kooten F. Magnesium sulfate in aneurysmal subarachnoid hemorrhage: a randomized controlled trial. Stroke. 2005 May. 36(5):1011-5. [Medline].
Velthuis BK, Van Leeuwen MS, Witkamp TD. Computerized tomography angiography in patients with subarachnoid hemorrhage: from aneurysm detection to treatment without conventional angiography. J Neurosurg. 1999 Nov. 91(5):761-7. [Medline].
Vespa PM, Gobin YP. Endovascular treatment and neurointensive care of ruptured aneurysms. Crit Care Clin. 1999 Oct. 15(4):667-84. [Medline].
Vinuela F, Murayama Y, Duckwiler GR. Present and future technical developments on aneurysm embolization. Impact on indications and anatomic results. Clin Neurosurg. 2000. 47:221-41. [Medline].
Viñuela F, Duckwiler G, Mawad M. Guglielmi detachable coil embolization of acute intracranial aneurysm: perioperative anatomical and clinical outcome in 403 patients. 1997. J Neurosurg. 2008 Apr. 108(4):832-9. [Medline].
Wermer MJ, van der Schaaf IC, Velthuis BK. Follow-up screening after subarachnoid haemorrhage: frequency and determinants of new aneurysms and enlargement of existing aneurysms. Brain. 2005 Oct. 128(Pt 10):2421-9. [Medline].
White PM, Wardlaw JM, Easton V. Can noninvasive imaging accurately depict intracranial aneurysms? A systematic review. Radiology. 2000 Nov. 217(2):361-70. [Medline].
Wiebers DO, Torres VE. Screening for unruptured intracranial aneurysms in autosomal dominant polycystic kidney disease. N Engl J Med. 1992 Sep 24. 327(13):953-5. [Medline].
Yuki I, Murayama Y, Vinuela F. Development of medical devices for neuro-interventional procedures: special focus on aneurysm treatment. Expert Rev Med Devices. 2005 Sep. 2(5):539-46. [Medline].
Zada G, Breault J, Liu CY, Khalessi AA, Larsen DW, Teitelbaum GP, et al. Internal carotid artery aneurysms occurring at the origin of fetal variant posterior cerebral arteries: surgical and endovascular experience. Neurosurgery. 2008 Jul. 63(1 Suppl 1):ONS55-61; discussion ONS61-2. [Medline].
Zaidat OO, Ionita CC, Hussain SI, Alexander MJ, Friedman AH, Graffagnino C. Impact of Ruptured Cerebral Aneurysm Coiling and Clipping on the Incidence of Cerebral Vasospasm and Clinical Outcome. J Neuroimaging. 2008 Aug 4. [Medline].
|Grade||Clinical Condition at Presentation|
|1||Asymptomatic or minimal headache and slight nuchal rigidity|
|2||Moderately severe or severe headache and nuchal rigidity; cranial neuropathy, no focal deficit|
|3||Drowsiness, confusion, or mild focal deficit|
|4||Stupor, moderate to severe hemiparesis|
|5||Deep coma, decerebrate posturing, moribund appearance|
|Grade||Glasgow Coma Scale Score||Clinical Findings|
|I||15||No headache or focal signs|
|II||15||Headache, nuchal rigidity, no focal signs|
|III||13-14||Headache, nuchal rigidity, no focal signs|
|IV||7-12||Headache, rigidity, focal signs|
|V||3-6||Headache, rigidity, focal signs|
|1||No blood detected|
|2||Diffuse thin layer of subarachnoid blood|
|3||Localized thrombus or thick layer of subarachnoid blood|
|4||Intracerebral or intraventricular hemorrhage with diffuse or no subarachnoid blood|