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Bryce Weir, Lew Disney, and Theodore Karrison

Object. The authors explore the risk of rupture in aneurysms categorized by size.

Methods. A computerized database of 945 patients with aneurysms treated between 1967 and 1987 was retrospectively established. All available clinical and radiological studies were abstracted. Because of the recent interest in the size of intracranial aneurysms in relation to their likelihood of rupture, the database was searched with respect to this parameter. In 390 patients representing 41% of all cases, aneurysms were measured by neuroradiologists at the time of diagnosis. In 78% of the 945 patients there was only one aneurysm, and of the 507 aneurysms that were measured, 60% were solitary. Of all patients, 86% had ruptured aneurysms. The average age of all patients was 47 years, and for those with ruptured aneurysms it was 46 years. Of the ruptured aneurysms, 77% were 10 mm or smaller, compared with 85% of the unruptured aneurysms. It was found that 40.3% of the ruptured aneurysms were on the anterior cerebral artery or anterior communicating artery, compared with 13% of the unruptured aneurysms. None of the cavernous internal carotid artery (ICA) aneurysms were ruptured and 65% of the ophthalmic artery (OphA) aneurysms were. Of the unruptured aneurysms, 15% were located in the cavernous ICA or the OphA. Of the ruptured aneurysms, 29% were on the middle cerebral artery, compared with 36% of the unruptured aneurysms. The mean size of ruptured and unruptured aneurysms showed no statistically significant increase with patient age, although the difference in size between the ruptured and unruptured aneurysms decreased with increasing age. The mean size of all ruptured aneurysms (10.8 mm) was significantly larger than the mean size of all unruptured aneurysms (7.8 mm, p < 0.001); the median sizes were 10 mm and 5 mm, respectively. The size of ruptured aneurysms in patients who died in the hospital was significantly larger than those in the patients who survived (12 mm compared with 9.9 mm, p = 0.004). Symptomatic unruptured aneurysms were significantly larger than incidental unruptured aneurysms (14.6 mm compared with 6.9 mm, p = 0.032), which were, in turn, larger than aneurysms that were unruptured and part of a multiple aneurysm constellation. Both ruptured and unruptured aneurysms were larger in male than in female patients, but not significantly.

Conclusions. Site and patient age, as well as lesion size, may affect the chance of rupture.

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R. Loch Macdonald, Axel Rosengart, Dezheng Huo, and Theodore Karrison

Object. The goal of this study was to determine factors associated with the development of symptomatic vasospasm among patients with aneurysmal subarachnoid hemorrhage (SAH) who participated in the randomized, double-blind, placebo-controlled trials of tirilazad between 1991 and 1997.

Methods. Data obtained from 3567 patients entered into trials of tirilazad were analyzed using uni- and multivariate logistic regression to determine factors that predict the development of symptomatic vasospasm. Symptomatic vasospasm was defined by clinical criteria accompanied by laboratory- and radiologically determined exclusion of other causes of neurological deterioration. Transcranial Doppler ultrasonographic and/or angiographic confirmation was not required. In these patients, the aneurysms were scheduled to be treated surgically, and no patient undergoing endovascular treatment was included. A multivariate analysis showed that factors significantly associated with vasospasm were age 40 to 59 years, history of hypertension, worse neurological grade, thicker blood clot on the cranial computerized tomography (CT) scan obtained on hospital admission, larger aneurysm size, presence of intraventricular hemorrhage (IVH), prophylactic use of induced hypertension, and not participating in the first European tirilazad study.

Conclusions. Symptomatic vasospasm was associated with the amount of SAH on the CT scan, the presence of IVH, and the patient's neurological grade. The association with patient age may reflect alterations in vessel reactivity associated with age. A history of hypertension may render the brain more susceptible to symptoms from vasospasm. The explanation for the relationships with aneurysm size, use of prophylactic induced hypertension, and the particular study is unclear.

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Bryce Weir, Christina Amidei, Gail Kongable, J. Max Findlay, Neal F. Kassell, John Kelly, Lanting Dai, and Theodore G. Karrison

Object. In this retrospective study the authors examined the aspect ratio (AR; the maximum dimension of the dome/width of the neck of an aneurysm) and compared the distribution of this ratio in a group of ruptured and unruptured aneurysms. A similar comparison was performed in relation to the maximum dimension of the aneurysm alone. The authors sought to evaluate the utility of these measures for differentiating ruptured and unruptured aneurysms.

Methods. Measurements were made of 774 aneurysms in 532 patients at three medical centers. One hundred twenty-seven patients harbored only unruptured lesions, 290 only ruptured lesions, and 115 both ruptured and unruptured lesions. Cases were included if angiograms were available for measurement and the status of the individual patient's aneurysm(s) was known.

The odds of a lesion falling in the ruptured aneurysm group increased with both the lesion's maximum size and the AR. The odds ratio for rupture rose progressively only for the AR. The distribution curves showed that ruptured aneurysms were larger and had greater ARs. The mean size of unruptured aneurysms was 7 mm and that of ruptured ones was 8 mm; the corresponding mean ARs were 1.8 and 3.4, respectively. The odds of rupture were 20-fold greater when the AR was larger than 3.47 compared with an AR less than or equal to 1.38. Only 7% of ruptured aneurysms had an AR less than 1.38 compared with 45% of unruptured lesions.

Conclusions. The AR is probably a useful index to calculate. A high AR might reasonably influence the decision to treat actively an unruptured aneurysm independent of its maximum size. Prospective studies are warranted.

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David McLone, David Frim, Richard Penn, Charles N. Swisher, Peter Heydemann, Kenneth M. Boyer, A. Gwendolyn Noble, Peter K. Rabiah, Shawn Withers, Kristen Wroblewski, Theodore Karrison, Samuel Hutson, Kelsey Wheeler, William Cohen, Joseph Lykins, and Rima McLeod


Hydrocephalus occurs in children with congenital toxoplasmosis and can lead to severe disability. In these cases, the decision to intervene is often influenced by the expectation of neurological recovery. In this study, clinical responses to neurosurgical intervention in children with hydrocephalus secondary to congenital toxoplasmosis are characterized.


Sixty-five participants with hydrocephalus due to congenital Toxoplasma gondii infection were evaluated as part of the National Collaborative Chicago-based Congenital Toxoplasmosis Study, and their neuroradiographic findings were reviewed. Clinical outcomes were scored on the basis of cognition and motor skills through the use of IQ scores and Gross Motor Function Classification System (GMFCS) level. Outcomes were then analyzed in relation to approach to management, anatomy of hydrocephalus, and time from diagnosis of hydrocephalus to surgical intervention.


There was considerable variation in the outcomes of patients whose hydrocephalus was treated in early life, ranging from normal cognitive and motor function to profound developmental delay and functional limitation. Of the 65 participants included in the study, IQ and GMFCS level were available for 46 (70.8%). IQ and motor score were highly correlated (r = −0.82, p < 0.001). There were people with differing patterns of hydrocephalus or thickness of cortical mantle on initial presentation who had favorable outcomes. Time to neurosurgical intervention data were available for 31 patients who underwent ventriculoperitoneal (VP) shunt placement. Delayed shunt placement beyond 25 days after diagnosis of hydrocephalus was associated with greater cognitive impairment (p = 0.02). Motor impairment also appeared to be associated with shunt placement beyond 25 days but the difference did not achieve statistical significance (p = 0.13). Among those with shunt placement within 25 days after diagnosis (n = 19), the mean GMFCS level was 1.9 ± 1.6 (range 1–5). Five (29.4%) of 17 of these patients were too disabled to participate in formal cognitive testing, after excluding 2 patients with visual difficulties or language barriers that precluded IQ testing. Of the patients who had VP shunt placement 25 or more days after diagnosis (n = 12), the mean GMFCS level was 2.7 ± 1.4 (range 1–4). Of these, 1 could not participate in IQ testing due to severe visual difficulties and 8 (72.7%) of the remaining 11 due to cognitive disability.


VP shunt placement in patients with hydrocephalus caused by congenital toxoplasmosis can contribute to favorable clinical outcomes, even in cases with severe hydrocephalus on neuroimaging. Shunt placement within 25 days of diagnosis was statistically associated with more favorable cognitive outcomes. Motor function appeared to follow the same pattern although it did not achieve statistical significance.