The long-term outcome in patients with multiple aneurysms. Incidence of late hemorrhage and implications for treatment of incidental aneurysms

One-stage Operation with Ipsilateral Two-Piece Craniotomies for a Case of Subarachnoid Hemorrhage with Multiple Intracranial Aneurysms

Subarachnoid hemorrhage (SAH) with multiple intracranial aneurysms is common, but the difficulties often arise in determining treatment strategy in the acute phase. We experienced a case of SAH with distal anterior cerebral artery aneurysm coexisting with middle cerebral artery and anterior communicating artery aneurysms, in which it was difficult to identify the precise rupture site preoperatively, and both pterional approach and interhemispheric approach were required in the acute phase of SAH. However, we could treat whole aneurysms in one stage and obtained an excellent outcome using our surgical procedure with ipsilateral frontotemporal and frontal parasagittal craniotomies through a single skin incision.

Spontaneous Subarachnoid Hemorrhage: Assessment of Prognosis and Initial Management in the Intensive Care Unit

Spontaneous subarachnoid hemorrhage (SAH) is asso ciated with high morbidity and mortality. Primary con servative or preoperative management in the intensive care unit aims at prevention, early detection, and treat ment of complications. In this article we review the literature on the value of initial clinical and laboratory findings in predicting complications and outcome after SAH. Current conservative management of SAH is briefly discussed.

Seven Intracranial Aneurysms in One Patient: Treatment and Review of Literature

Before the advent of endovascular coiling, patients with multiple intracranial aneurysms were treated with surgical clipping; however, with the advancements in endovascular technology, intracranial aneurysms can be treated with surgical clipping and/or endovascular coiling. We describe a case of subarachnoid hemorrhage in a patient with 7 intracranial aneurysms. A 45-year-old female developed a sudden headache and left sided hemiparesis. Initial workup showed a subarachnoid hemorrhage in the right Sylvian fissure. Further angiographic workup showed 7 intracranial aneurysms (left and right middle cerebral artery bifurcation, right middle cerebral artery, anterior communicating artery, left posterior communicating artery, right posterior inferior cerebellar artery, and left superior cerebellar artery). The patient underwent two craniotomies for surgical clipping of the anterior circulation aneurysms and endovascular stent-assisted coils for the posterior circulation aneurysms. The need for anti-platelet agents for endovascular treatment of the posterior circulation aneurysms and clinical presentation warranted surgical clipping of the anterior circulation aneurysms prior to endovascular therapy. We describe a case report and decision making for a patient with multiple intracranial aneurysms treated with surgical clipping and endovascular coiling.

"Microbleeding" from intracranial aneurysms: Local hemosiderin deposition identified during microsurgical treatment of unruptured intracranial aneurysms

BACKGROUND

During elective surgery for unruptured aneurysms, we have identified a group of patients with hemosiderin staining of the pial surface immediately adjacent to the aneurysm dome suggesting a remote and unrecognized history of microbleeding from the aneurysm. These cases form the basis for this report.

METHODS

Medical records of 421 unruptured cerebral aneurysm patients treated surgically between January 2003 and September 2010 were retrospectively reviewed. Patients with a history of prior subarachnoid hemorrhage, craniotomy, or significant closed head injury were excluded from review. Records were reviewed for intraoperative descriptions of hemosiderin deposition in the vicinity of the aneurysm as well as history of headaches, time to presentation, comorbidities, aneurysm characteristics, procedures, and radiologic imaging.

RESULTS

Local hemosiderin staining immediately adjacent to the aneurysm was identified intraoperatively in 13 cases. Each of these patients had a history of remote atypical headache prior to presentation. Eight of these patients (62%) had aneurysms described as particularly "thin-walled" at the time of surgery. Aneurysm locations included the internal carotid artery (ICA) (54%), middle cerebral artery (MCA) (23%), anterior communicating artery (ACOMMA) (15%), and the anterior cerebral artery (ACA) (8%). More than half (54%) of these patients had a history of smoking, while 31% had hypertension, and 23% had a history of alcohol abuse. Dyslipidemia and family history of aneurysms were present in 15% and hypercholesterolemia was noted in one patient (8%).

CONCLUSION

We suggest this group of patients had suffered a "microbleed" resulting in local hemosiderin deposition next to the aneurysm. The origins and clinical implications of such microbleeds are unknown and warrant further investigation.

Angiographic characteristics of ruptured paraclinoid aneurysms: risk factors for rupture

BACKGROUND

The diagnosis and treatment of unruptured paraclinoid aneurysms has been increasing with the recent advent of diagnostic tools and less invasive endovascular therapeutic options. Considering the low incidence of rupture, investigation of the characteristics of ruptured paraclinoid aneurysm is important to predict rupture risk of the paraclinoid aneurysms. The objective of this study is to evaluate probable factors for rupture by analyzing the characteristics of ruptured paraclinoid aneurysms.

METHODS

A total of 2,276 aneurysms (1,419 ruptured and 857 unruptured) were diagnosed and treated endovascularly or microsurgically between 2001 and 2011. Among them, 265 were paraclinoid aneurysms, of which 37 were ruptured. Removing 12 blister-like aneurysms, 25 ruptured and 228 unruptured saccular aneurysms were included and the medical records and radiological images were retrospectively analyzed.

RESULTS

Of 25 aneurysms, 16 (64.0%) were located in the superior direction. Five were inferior located lesions (20%) and four were medially located lesions (16.0%). Laterally located lesions were not found. The mean size of aneurysms was 9.4 ± 5.6 mm. Ten aneurysms (40.0%) were ≥ 10 mm in size. Thirteen aneurysms (52.0%) were lobulated. The superiorly located aneurysms were larger than the other aneurysms (10.3 ± 5.8 mm vs. 7.7 ± 4.9 mm) and more frequently lobulated (ten of 16 vs. three of nine). In a comparative analysis, the ruptured aneurysms were located more in the superior direction compared with unruptured aneurysms (64 vs. 23.2%, p < 0.0001). Large aneurysms (36.0 vs. 7.9%, p < 0.0001), longer fundus diameter (mean 9.4 ± 5.6 vs. 4.8 ± 3.3 mm, p = 0.001), dome-to-neck ratio (mean 1.8 ± 0.9 vs. 1.2 ± 0.5, p < 0.0001), and lobulated shape aneurysms were more likely to be ruptured aneurysms (13 of 25 ruptured aneurysms, 52.0%, p = 0.001).

CONCLUSIONS

Rupture risk of the paraclinoid aneurysm is very low. However, superiorly located paraclinoid aneurysms appear more likely to rupture than other locations. Angiographically, more conservative indication for the treatment of paraclinoid aneurysm should be recommended except for superior located lesions.

Management of unruptured brain aneurysms: retrospective analysis of a single centre experience

Embolization is very effective in preventing bleeding of unruptured aneurysms with lower rates of mortality and morbidity than surgical treatment. Neurosurgery remains, however, a good alternative. This retrospective analysis examined data stored the digital database of Bellaria Hospital Radiology Department, evaluating patients, treatments and devices used as well as outcomes and complications. Therapy should be tailored to each individual case to offer each patient the best treatment. Out of 265 unruptured intracranial aneurysms detected, 182 were treated by embolization. 16 cases presented complications (12 only radiologically found); severe clinical consequences occurred in 3%: one ischaemia and five haemorrhages. Conservative treatment was adopted in 21 patients. Long-term follow-up is mandatory as aneurysms could increase their size and develop an irregular morphology in ten years' time. Endovascular embolization is a very effective treatment with positive outcomes in the majority of cases and a percentage of retreatments of 8%. In order to increase the number of successful cases, a multidisciplinary cooperation with neurosurgeons is strongly recommended.

Intracranial aneurysm formation in type-one diabetes rats

BACKGROUND & OBJECTIVE

Diabetes mellitus (DM) plays an important role in the pathogenesis of vascular complications including arteriosclerosis and ischemic stroke. Whether DM impacts intracranial aneurysm (IA) formation has not been extensively investigated. In this study, we tested the underlying mechanism of type one DM (T1DM) induced IA formation in rats.

EXPERIMENTAL APPROACHES

T1DM was induced by streptozotocin injection. Rats were euthanized at 0, 4 and 10 weeks after T1DM induction. To evaluate cerebral vascular perfusion, Fluorescein isothiocyanate - dye was injected at 5 min prior to euthanasia. Vascular perfusion was measured by laser scanning confocal microscopy. Trichrome, Elastica van Gieson, alpha-smooth muscle actin (a-SMA) and receptor of advanced glycation end-products (RAGE), toll-like receptor 4 (TLR4) and matrix metalloproteinase 9 (MMP9) immunostaining were performed. The IA formation was classified by 0-3 stages: 0: Normal; 1: Endothelial damage; 2: Moderate protrusion; and 3: Saccular aneurysm formation.

RESULTS

T1DM significantly increased IA formation identified by the classification of aneurysmal changes compared with non-DM rats (p<0.05). However, T1DM induced IA formations were classified as stage 1 and stage 2, but not stage 3. Cerebral vascular perfusion was significantly decreased in T1DM rats compared to non-DM rats (p<0.01). DM10W rats exhibited a significant decrease of cerebral vascular perfusion compared to DM4W rats (p<0.05). T1DM rats also significantly increased the internal carotid artery (ICA) intimae and media thickness, and decreased the internal carotid artery diameter compared to non-DM rats. RAGE, MMP9 and TLR4 expression were significantly increased in T1DM rats compared to non-DM rats. The increased RAGE, TLR4 and MMP9 significantly correlated with IA formation (p<0.05).

CONCLUSION

T1DM increases IA formation. The increased RAGE, MMP9 and TLR4 expressions might contribute to IA formation in T1DM rats.

Benefits of early aneurysm surgery: Southern Iran experience

Background:

Neurovascular surgery has been practiced in Shiraz, the main referral center of the Southern Iran, for over 30 years; however, the trend has accelerated tremendously in recent years following subspecialization of neurovascular surgery in Shiraz, Department of Neurosurgery. Over 100 patients are operated each year, and nearly all are addressed during the first 72 hours after presentation.

Methods:

In this paper, we focus on the description of techniques we apply for early clipping of ruptured intracranial aneurysms in the anterior circulation. Improvements in outcome, mortality, and rebleeding rates are also discussed.

Results:

Mortality and rebleeding rates have declined significantly since the institution of new techniques.

Conclusion:

The establishment of early surgery for ruptured anterior circulation aneurysms through the lateral supraorbital approach along with specific anesthetic protocol has resulted in significant improvement of morbidity, mortality, and rebleeding rates at our department.

Subarachnoid hemorrhage in Kashmir: Causes, risk factors, and outcome

Context:

Kashmir, a snow bound and mountain locked valley, is populated by about 7 million ethnic and non-migratory Kashmiris who have specific dietary and social habits than rest of the world. The neurological disorders are common in Kashmiri population.

Aims:

To study the prevalence and outcome of spontaneous intracranial subarachnoid hemorrhage (SAH) in Kashmir compared withother parts of the world.

Settings and Design:

A retrospective and hospital based study from 1982 to 2010 in the single and only Neurosurgical Centre of the State of Jammu and Kashmir.

Materials and Methods:

A hospital based study, in which, information concerning all Kashmiri patients was collected from the case sheets, patient files, discharge certificates, death certificates, and telephonic conversations with the help of Medical Records Department and Central Admission Register of Sher–i-Kashmir Institute of Medical Sciences, Kashmir India.

Statistical Analysis:

Analysis of variance and students T-test were used at occasions.

Results:

Incidence of SAH in Kashmiris is about 13/100,000 persons per year. SAH comprises 31.02% of total strokes and aneurysmal ruptures are cause of 54.35% SAHs. The female suffers 1.78 times more than the male. Total mortality of 36.60% was recorded against a good recovery of 14.99%. The familial SAHs and multiple aneurysms were also common. Intra-operative finding of larger aneurysmal size than recorded on pre-operative computed tomography (CT) angiogram of same patients was noteworthy. In 493 patients of SAH, the angiography revealed 705 aneurysms.

Conclusion:

Spontaneous intracranial subarachnoid hemorrhage, due to aneurysmal rupture, is common in Kashmir, with worst outcome. Food habits like “salt-tea twice a day”, group-smoking of wet tobacco like “Jejeer”, winter season, female gender, hypertension, and inhalation of “Kangri” smoke are special risk factorsof SAH, in Kashmiris. The plain CT brain and CT angiography are best diagnostic tools. The preventive measures for aneurysmal formation and rupture seems most promising management of future. The detachable endovascular aneurysmal occupying video assisted micro-camera capsules or plugs may be future treatment.

Identification of a dichotomy in morphological predictors of rupture status between sidewall- and bifurcation-type intracranial aneurysms

OBJECT

Prediction of aneurysm rupture likelihood is clinically valuable, given that more unruptured aneurysms are being discovered incidentally with the increased use of imaging. The authors set out to evaluate the relative performance of morphological features for rupture status discrimination in the context of the divergent geometrical and hemodynamic characteristics of sidewall- and bifurcation-type aneurysms.

METHODS

Catheter 3D rotational angiographic images of 271 consecutive aneurysms (101 ruptured, 135 bifurcation type) were used to assess the following parameters in 3D: maximum diameter (D(max)), height, height/width ratio, aspect ratio, size ratio, nonsphericity index, and inflow angle. Univariate statistics applied to the bifurcation, sidewall, and combined (bifurcation + sidewall) sets identified significant features for inclusion in multivariate analysis yielding area under the curve (AUC) and optimal thresholds in the receiver-operating characteristic. Furthermore, a computational fluid dynamics analysis was performed to evaluate the flow and wall shear stress conditions inside sidewall and bifurcation aneurysms at different inflow angles.

RESULTS

The mean D(max), height, and inflow angle were significantly greater in ruptured sidewall aneurysms than in unruptured sidewall aneurysms, but showed no difference between ruptured and unruptured bifurcation lesions. There was a statistically significant difference between ruptured and unruptured aneurysms for all measured features in the combined set. Multivariate analysis identified the following: 1) nonsphericity index as the only rupture status discriminator in bifurcation lesions (AUC = 0.67); 2) height/width ratio, size ratio, and inflow angle as strong discriminators in sidewall lesions (AUC = 0.87); and 3) height/width ratio, inflow angle, and size ratio as intermediate discriminators in the combined group (AUC = 0.76). Computational fluid dynamics analysis showed that although increasing inflow angle in a sidewall model led to deeper penetration of flow, higher velocities, and higher wall shear stress inside the aneurysm dome, it produced the exact opposite results in a bifurcation model.

CONCLUSIONS

Retrospective morphological and hemodynamic analysis point to a dichotomy between sidewall and bifurcation aneurysms with respect to performance of shape and size parameters in identifying rupture status, suggesting the need for aneurysm type-based analyses in future studies. The current most commonly used clinical risk assessment metric, D(max), was found to be of no value in differentiating between ruptured and unruptured bifurcation aneurysms.

Proximity to the treating centre and outcomes following subarachnoid hemorrhage

BACKGROUND

In the management of subarachnoid hemorrhage (SAH), the potential for early complications and the centralization of limited resources often challenge the delivery of timely neurosurgical care. We sought to determine the impact of proximity to the accepting neurosurgical centre on outcomes following aneurysmal SAH.

METHODS

Using administrative data, we analyzed patients undergoing treatment for aneurysmal subarachnoid hemorrhage at neurosurgical centres in Ontario between 1995 and 2004. We compared mortality for patients receiving treatment at a centre in their county (in-county) versus those treated from outside counties (out-of-county). We also examined the impact of distance from the patient's residence to the treating centre.

RESULTS

The mortality rates were significantly lower for in-county versus out-of-county patients (23.5% vs. 27.6%, p=0.009). This advantage remained significant after adjusting for potential confounders (HR=0.84, p=0.01). The relationship between distance from the treating centre and mortality was biphasic. Under 300 km, mortality increased with increasing distance. Over 300 km, a survival benefit was observed.

CONCLUSIONS

Proximity to the treating neurosurgical centre impacts survival after aneurysmal SAH. These results have significant implications for the triage of these critically ill patients.

Risk factors for the formation and rupture of intracranial saccular aneurysms in Shimane, Japan

BACKGROUND

Prevention of aneurysmal subarachnoid hemorrhage (SAH) can be achieved by reducing risk factors, which include those for aneurysm formation and aneurysm rupture. However, neither of these 2 factors has been discussed separately so far. A case control study was undertaken in Shimane, Japan, to identify modifiable risk factors for the formation and rupture of aneurysms.

METHODS

This study included 858 patients with ruptured aneurysms, 285 patients with unruptured aneurysms without a history of SAH, and 798 control subjects. Hypertension, diabetes mellitus, heart disease, hypercholesterolemia, cigarette smoking, and alcohol consumption were assessed as risk factors by using conditional logistic regression.

RESULTS

After adjustment for other risk factors, hypertension was the most powerful risk factor for aneurysm formation, regardless of age and sex, followed by hypercholesterolemia, heart disease, and cigarette smoking, whereas diabetes mellitus and daily drinking were insignificant for aneurysm formation. Hypertension and daily drinking were not related to the risk of aneurysm rupture, regardless of age and sex, whereas cigarette smoking was associated with an increased risk of aneurysm rupture in patients 60 years or older and in men. In contrast, hypercholesterolemia was strongly associated with a decreased risk of rupture, regardless of age and sex, and in patients with small aneurysms (<5 mm). Diabetes mellitus and heart disease were also related to a decreased risk of rupture in patients 60 years or older and in women.

CONCLUSION

Identification of risk factors for aneurysm formation and rupture separately seems to be pivotal for reducing the incidence of SAH.

Management of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Acute aneurysmal subarachnoid hemorrhage (SAH) is a complex multifaceted disorder that plays out over days to weeks. Many patients with SAH are seriously ill and require a prolonged intensive care unit stay. Cardiopulmonary complications are common. The management of patients with SAH focuses on the anticipation, prevention, and management of these secondary complications.

DATA SOURCES

Source data were obtained from a PubMed search of the medical literature.

DATA SYNTHESIS AND CONCLUSION

The rupture of an intracranial aneurysm is a sudden devastating event with immediate neurologic and cardiac consequences that require stabilization to allow for early diagnostic angiography. Early complications include rebleeding, hydrocephalus, and seizures. Early repair of the aneurysm (within 1-3 days) should take place by surgical or endovascular means. During the first 1-2 weeks after hemorrhage, patients are at risk of delayed ischemic deficits due to vasospasm, autoregulatory failure, and intravascular volume contraction. Delayed ischemia is treated with combinations of volume expansion, induced hypertension, augmentation of cardiac output, angioplasty, and intra-arterial vasodilators. SAH is a complex disease with a prolonged course that can be particularly challenging and rewarding to the intensivist.

Unruptured intracranial aneurysms and the assessment of rupture risk based on anatomical and morphological factors: sifting through the sands of data

Aneurysmal subarachnoid hemorrhage continues to have high rates of morbidity and mortality for patients despite optimal medical and surgical management. Due to the fact that aneurysmal rupture can be such a catastrophic event, preventive treatment is desirable for high-risk lesions. Given the variability of the literature evaluating unruptured aneurysms regarding basic patient population, clinical practice, and aneurysm characteristics studied, such as size, location, aspect ratio, relationship to the surrounding vasculature, and the aneurysm hemodynamics, a metaanalysis is nearly impossible to perform. This review will instead focus on the various anatomical and morphological characteristics of aneurysms reported in the literature with an attempt to draw broad inferences and serve to highlight pressing questions for the future in our continued effort to improve clinical management of unruptured intracranial aneurysms.

What Is the Significance of a Large Number of Ruptured Aneurysms Smaller than 7 mm in Diameter?

OBJECTIVE

The International Study of Unruptured Intracranial Aneurysms (ISUIA) reported that the 5-year cumulative rupture rate of small unruptured aneurysms less than 7 mm in diameter is very low depending on the aneurysm's location. However, we have seen a large number of ruptured aneurysms less than 7 mm in clinical practice. The purpose of this study was to review our experience and to measure the size and location at which aneurysms ruptured in our patient population.

METHODS

We reviewed the characteristics of aneurysms, such as size and location, from the original angiograms of patients who were admitted to our hospital between January 2004 and December 2007. All aneurysms were treated surgically or through endovascular procedures.

RESULTS

Interventional or surgical treatment was given to a total of 889 patients, including 568 females and 321 males. At the time of our study, 627 cases were ruptured aneurysms and 262 cases were unruptured aneurysms. Of the ruptured cases, the mean diameter of the aneurysm was 6.28 mm. We found that 71.8% of ruptured aneurysms were smaller than 7 mm in diameter, and 87.9%, were smaller than 10 mm. Based on location, the data show that anterior communicating artery aneurysms most often presented with rupture sizes less than 7 mm (76.8%) and 10 mm (92.1%) in diameter. Most ruptured aneurysms were less than 7 mm in size, although recent studies have noted that small aneurysms are less likely to rupture.

CONCLUSION

Although the natural history of unruptured intracranial aneurysms remains controversial, the aneurysm size and location play a signigicant role in determining the risk of rupture. Larger sample sizes and a long term study are needed to reveal the natural history and the rupture risk of unruptured intracranial aneurysms because the size of most ruptured aneurysms was less than 7 mm in diameter in our series.

Reporting standards for endovascular repair of saccular intracranial cerebral aneurysms

BACKGROUND AND PURPOSE

The goal of this article is to provide consensus recommendations for reporting standards, terminology, and written definitions when reporting on the radiological evaluation and endovascular treatment of intracranial, cerebral aneurysms. These criteria can be used to design clinical trials, to provide uniformity of definitions for appropriate selection and stratification of patients, and to allow analysis and meta-analysis of reported data.

METHODS

This article was written under the auspices of the Joint Writing Group of the Technology Assessment Committee, Society of NeuroInterventional Surgery, Society of Interventional Radiology; Joint Section on Cerebrovascular Neurosurgery of the American Association of Neurological Surgeons and Congress of Neurological Surgeons; and Section of Stroke and Interventional Neurology of the American Academy of Neurology. A computerized search of the National Library of Medicine database of literature (PubMed) from January 1991 to December 2007 was conducted with the goal to identify published endovascular cerebrovascular interventional data about the assessment and endovascular treatment of cerebral aneurysms useful as benchmarks for quality assessment. We sought to identify those risk adjustment variables that affect the likelihood of success and complications. This article offers the rationale for different clinical and technical considerations that may be important during the design of clinical trials for endovascular treatment of cerebral aneurysms. Included in this guidance article are suggestions for uniform reporting standards for such trials. These definitions and standards are primarily intended for research purposes; however, they should also be helpful in clinical practice and applicable to all publications.

CONCLUSIONS

The evaluation and treatment of brain aneurysms often involve multiple medical specialties. Recent reviews by the American Heart Association have surveyed the medical literature to develop guidelines for the clinical management of ruptured and unruptured cerebral aneurysms. Despite efforts to synthesize existing knowledge on cerebral aneurysm evaluation and treatment, significant inconsistencies remain in nomenclature and definition for research and reporting purposes. These operational definitions were selected by consensus of a multidisciplinary writing group to provide consistency for reporting on imaging in clinical trials and observational studies involving cerebral aneurysms. These definitions should help different groups to publish results that are directly comparable.

Reprint of: SYMPOSIUM ON CEREBROVASCULAR DISEASES. Pathogenesis, Natural History, and Treatment of Unruptured Intracranial Aneurysms

Unruptured intracranial aneurysms (UIAs) are a major public health issue. These lesions have become increasingly recognized in recent years with the advent of advanced cerebral imaging techniques. Epidemiological evidence from multiple sources suggests that most intracranial aneurysms do not rupture. Therefore, it is desirable to identify which UIAs are at greatest risk of rupture when considering which to repair. It is important to compare size-, site-, and group-specific natural history rates with size-, site-, and age-specific morbidity and mortality associated with UIA repair because increased natural history risk often is associated with increased risk of aneurysm repair. Patient age is crucial in decision making because of its major effect on operative morbidity and mortality; however, it does not substantially affect natural history. The effect of age is most notable in patients about 50 years of age and older for open surgery and about 70 years of age and older for endovascular procedures. In general, rupture risk is lowest for patients in asymptomatic group 1 (no history of subarachnoid hemorrhage) with UIAs less than 7 mm in diameter in the anterior circulation. Surgical morbidity and mortality are most favorable for asymptomatic patients younger than 50 years who have UIAs less than 24 mm in diameter in the anterior circulation and no history of ischemic cerebrovascular disease. Endovascular morbidity and mortality may be less age dependent, and this could favor endovascular procedures, particularly in patients aged 50 to 70 years. An important issue is determining immediate vs long-term risk regarding treatment effectiveness and durability. This issue emphasizes the importance of long-term follow-up in patients after surgical and endovascular procedures.

[Endovascular therapy for intracranial aneurysms]

During the past 5 to 10 years, therapy for aneurysms has seen dramatic changes. In some centers they happened before the ISAT study, in others afterward. Endovascular treatment is now the method of choice for intracranial aneurysms whenever possible. Large centers are using it for 70-80% of aneurysms. Due to constant development of new interventional materials, even wide-necked aneurysms in practically all localizations can be treated today with very dependable results. The remaining aneurysms are quite difficult to treat and represent a great neurosurgical challenge. Despite all the technical improvements, closure is still not the most difficult element of the therapeutic procedure. This role is played by the subarachnoidal hemorrhage, which still is decisive for patient outcome. All related disciplines are urgently called upon to solve the unresolved problems as quickly and efficiently as possible through determined research.

Deficiencies in estrogen-mediated regulation of cerebrovascular homeostasis may contribute to an increased risk of cerebral aneurysm pathogenesis and rupture in menopausal and postmenopausal women

Despite the catastrophic consequence of ruptured intracranial aneurysms, very little is understood regarding their pathogenesis, and there are no reliable predictive markers for identifying at-risk individuals. Few studies have addressed the molecular pathological basis and mechanisms of intracranial aneurysm formation, growth, and rupture. The pathogenesis and rupture of cerebral aneurysms have been associated with inflammatory processes, and these have been implicated in the digestion and breakdown of vascular wall matrix. Epidemiological data indicate that the risk of cerebral aneurysm pathogenesis and rupture in women rises during and after menopause as compared to premenopausal women, and has been attributed to hormonal factors. Moreover, experimental evidence supports a role for estrogen in the modulation of each phase of the inflammatory response implicated in cerebral aneurysm pathogenesis and rupture. While the risk of aneurysm rupture in men also increases with age, this increased risk has been attributed to other recognized risk factors including cigarette smoking, use of alcohol, and history of hypertension, all of which are more common in men than women. We hypothesize, therefore, that decreases in both circulating estrogen levels and cerebrovascular estrogen receptor density may contribute to an increased risk of cerebral aneurysm pathogenesis and rupture in women during and after menopause. To test our hypothesis, experiments are needed to identify genes regulated by estrogen and to evaluate gene expression and intracellular mechanisms in cells/tissues exposed to varying concentrations and duration of treatment with estrogen, metabolites of estrogen, and selective estrogen receptor modulators (SERMs). Furthermore, it is not likely that the regulation of cerebrovascular homeostasis is due to the actions of estrogen alone, but rather the interplay of estrogen and other hormones and their associated receptor expression. The potential interactions of these hormones in the maintenance of normal cerebrovascular tone need to be elucidated. Additional studies are needed to define the role that estrogen and other sex hormones may play in the cerebrovascular circulation and the pathogenesis and rupture of cerebral aneurysms. Efforts directed at understanding the basic pathophysiological mechanisms of aneurysm pathogenesis and rupture promise to yield dividends that may have important therapeutic and clinical implications. The development of non-invasive tools such as molecular MRI for the detection of specific cells, molecular markers, and tissues may facilitate early diagnosis of initial pathophysiological changes that are undetectable by clinical examination or other diagnostic tools, and can also be used to evaluate the state of activity of cerebral aneurysm pathogenesis before, during, and after treatment.

Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography

OBJECTIVE

The aim of the study was to report about accurate size and location of a consecutive series of ruptured and unruptured aneurysms taking the complex 3-dimensional (3D) anatomy and parent vessel morphology into consideration by using the newly developed 3D rotational angiography (3D-RA).

METHODS

One hundred eighteen consecutive patients with 155 saccular intracranial aneurysms were included in the study and received 3D-RA reconstructions for measurement of maximal height and width of the aneurysmal sac. Statistical evaluation compared values for ruptured (n = 83) and unruptured (n = 72) aneurysms.

RESULTS

Mean height and width of unruptured aneurysms were 5.7 and 5.7 mm; of ruptured aneurysms, 6.7 and 6.1 mm (not significant, P = .7 for height and P = .9 for width). The majority of ruptured aneurysms, 81.9% and 59%, were smaller than 10 and 7 mm; likewise, 81.9% and 68.1% of unruptured aneurysms were smaller than 10 and 7 mm. The difference in frequency of small (<10/<7 mm) aneurysms between unruptured and ruptured aneurysms was not significant (P = 1.0 and .32, respectively). The majority (69.4%) of small ruptured aneurysms (<7 mm) were located in the anterior circulation. Most ruptured aneurysms were in the size group 4 to 6 mm in height and 2 to 4 mm in width, and a critical threshold size for aneurysm rupture could not be identified.

CONCLUSIONS

An automated calibration procedure applied to all images and excellent visualization of aneurysm and parent vessel morphology using 3D-RA allow accurate size measurement of intracranial aneurysms which may be smaller than previously thought. Small aneurysm (<7 mm), also in the anterior circulation, should be carefully evaluated for treatment.

Anévrismes intracrâniens non rompus : que proposer ?

Intracranial unruptured aneurysm (ICUA) has become a common condition for patient consultation. The mortality rate after fissuration is estimated to be between 52% and 85.7%. The final therapeutic decision results from a balance between the risk of rupture and risks related to the aneurysmal exclusion. Analysis of the risk of rupture risk enables a classification of risk factors. Depending on the circumstances of diagnosis, we considered the ICUA at high risk of rupture for incidental ICUA larger than 7 mm and in the event of associated aneurysms. Classifying by morphologic features, high-risk ICUA were located in the vertebrobasilar system (RR: 4.4; 95%CI: 2.7-6.8), those with a size between 7 and 12 mm (RR: 3.3; 95%CO: 1.3-8.2), larger than 12 mm (RR: 17; 95%CI: 8-36.1), those that were multilobular or a larger size and those ones with a index P/L superior to 3.4 (risk x20). Familial ICUA would expose to a major rupture risk (2 to 7 times sporadic ICUA). Some systemic factors were related to ICUA rupture: arterial hypertension (RR: 1.46; 95%CI: 1.01-2.11) and smoking addiction (RR: 3.04; 95%CI: 1.21-7.66). After microsurgical exclusion, the morbidity and mortality rates were 10% and 2% respectively. Some microsurgical morbidity factors were identified: age (32%>65 years), size (14%>15 mm), vertebrobasilar location and temporary occlusion. The rupture incidence after microsurgical exclusion was estimated 0.26%/year. After endovascular exclusion, the morbidity and mortality rates were 8% and 1% respectively. The complete exclusion rate varied between 47% and 67%. The rupture risk was estimated at 0.9%/year. Treatment recommendations were classified into 3 categories.

Management of ruptured aneurysms combined with coexisting aneurysms

In patients suffering from subarachnoid haemorrhage (SAH) and presenting with multiple intracranial aneurysms (MIA) two questions have to be decided on: 1st when is the ideal moment to eliminate the ruptured aneurysm and 2nd when to treat the coexisting aneurysms. In our series we retrospectively analysed 124 SAH-patients presenting with a total of 323 aneurysms. In 57 patients the ruptured aneurysm and all coexisting aneurysms were clipped during the first operation, whereas in 9 patients only some of the coexisting aneurysms (group-A; age in median 55 years) were clipped besides the ruptured one. In 55 patients (group-B; age in median 55 years) the first operation was restricted to clipping the ruptured aneurysm, dealing with the coexisting aneurysm subsequently. Immediately after admission 3 patients passed away. One of the 64 patients waiting (average 60 days, median 14 days) for the subsequent clipping of the not yet secured aneurysms suffered a SAH. Six to 12 months after the initial SAH, 78% of the cases in both groups reached a Glasgow Outcome Score of 4 or 5. Even if in patients with coexisting unruptured intracranial aneurysms the elimination of each and every aneurysm is recommended, the advantages of an unstaged procedure versus the additional strain caused by the prolongation of the procedure, e.g. approach over the midline, 2 or more craniotomies, and the risk of additional ischemic damage to the brain, caused by increased manipulation of cerebral arteries and brain tissue, have to be carefully considered. This is of special importance in dealing with patients in higher Hunt and Hess grades.

Prediction of Cerebral Vasospasm in Patients Presenting with Aneurysmal Subarachnoid Hemorrhage: A Review

OBJECTIVE:

Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mortality rates, even after the aneurysm has been treated. A substantial amount of experimental and clinical research has been conducted in an effort to predict and prevent its occurrence. This research has contributed to significant advances in the understanding of the mechanisms leading to cerebral vasospasm. The ability to accurately and consistently predict the onset of cerebral vasospasm, however, has been challenging. This topic review describes the various methodologies and approaches that have been studied in an effort to predict the occurrence of cerebral vasospasm in patients presenting with SAH.

METHODS:

The English-language literature on the prediction of cerebral vasospasm after aneurysmal SAH was reviewed using the MEDLINE PubMed (1966–present) database.

RESULTS:

The risk factors, diagnostic imaging, bedside monitoring approaches, and pathological markers that have been evaluated to predict the occurrence of cerebral vasospasm after SAH are presented.

CONCLUSION:

To date, a large blood burden is the only consistently demonstrated risk factor for the prediction of cerebral vasospasm after SAH. Because vasospasm is such a multifactorial problem, attempts to predict its occurrence will probably require several different approaches and methodologies, as is done at present. Future improvements in the prevention of cerebral vasospasm from aneurysmal SAH will most likely require advances in our understanding of its pathophysiology and our ability to predict its onset.

Fourier analysis of intracranial aneurysms: towards an objective and quantitative evaluation of the shape of aneurysms

Shape irregularities of intracranial aneurysms may indicate an increased risk of rupture. To quantify morphological differences, Fourier analysis of the shape of intracranial aneurysms was introduced. We compared the morphology of 45 unruptured (UIA) and 46 ruptured intracranial aneurysms (RIA) in 70 consecutive patients on the basis of 3D-rotational angiography. Fourier analysis, coefficient of roundness and qualitative shape assessment were determined for each aneurysm. Morphometric analysis revealed significantly smaller coefficient of roundness (P < 0.02) and higher values for Fourier amplitudes numbers 2, 3 and 7 (P < 0.01) in the RIA group, indicating more complex and irregular morphology in RIA. Qualitative assessment from 3D-reconstructions showed surface irregularities in 78% of RIA and 42% of UIA (P < 0.05). Our data have shown significant differences in shape between RIA and UIA, and further developments of Fourier analysis may provide an objective factor for the assessment of the risk of rupture.

Interactions between melatonin and estrogen may regulate cerebrovascular function in women: clinical implications for the effective use of HRT during menopause and aging

A number of clinical trials associated with the Women's Health Initiative (WHI) have assessed the potential benefits of hormone replacement therapy (HRT) for protection against the development of cardiovascular disease and memory loss in menopausal women. The results of the WHI Memory Study suggest that HRT increases the risk of stroke and dementia in menopausal women. This finding has called into question the results of hundreds of basic science studies that have suggested that estrogen could protect brain cells from damage and improve cognition. A number of researchers have argued that inappropriate formulation, improper dosing, a limited study population, and poor timing of administration likely contributed to the reported findings from the clinical trial. Regarding appropriate formulation, it has been suggested that interactions between estrogen and other hormones should be considered for further investigation. A review of the literature has led us to conclude that a thorough investigation into such hormonal interactions is warranted. We hypothesize that the increased risk of cerebrovascular disease observed in menopausal women may, in part, be due to changes in the circulating levels of melatonin and estrogen and their modulatory affects on many relevant endothelial cell biological activities, such as regulation of vascular tone, adhesion to leukocytes, and angiogenesis, among others. Our hypothesis is supported by numerous studies demonstrating the reciprocal inhibitory effects of melatonin and estrogen on vascular tone, neuroprotection, and receptor expression. We believe that a thorough analysis of the distribution, localization, expression, quantification, and characterization of hormonal receptor subtypes, as well as changes in structural morphology in diseased and normal, healthy cerebrovascular tissue, will substantially aid in our understanding of the effects of HRT on the cerebrovascular circulation. The application of new molecular biological techniques such as tissue microarray analysis, gene and protein arrays, and multi-photon confocal microscopy may be of tremendous benefit in this regard.

Pathogenesis, natural history, and treatment of unruptured intracranial aneurysms

Unruptured intracranial aneurysms (UIAs) are a major public health issue. These lesions have become increasingly recognized in recent years with the advent of advanced cerebral imaging techniques. Epidemiological evidence from multiple sources suggests that most intracranial aneurysms do not rupture. Therefore, it is desirable to identify which UIAs are at greatest risk of rupture when considering which to repair. It is important to compare size-, site-, and group-specific natural history rates with size-, site-, and age-specific morbidity and mortality associated with UIA repair because increased natural history risk often is associated with increased risk of aneurysm repair. Patient age is crucial in decision making because of its major effect on operative morbidity and mortality; however, it does not substantially affect natural history. The effect of age is most notable in patients about 50 years of age and older for open surgery and about 70 years of age and older for endovascular procedures. In general, rupture risk is lowest for patients in asymptomatic group 1 (no history of subarachnoid hemorrhage) with UIAs less than 7 mm in diameter in the anterior circulation. Surgical morbidity and mortality are most favorable for asymptomatic patients younger than 50 years who have UIAs less than 24 mm in diameter in the anterior circulation and no history of ischemic cerebrovascular disease. Endovascular morbidity and mortality may be less age dependent, and this could favor endovascular procedures, particularly in patients aged 50 to 70 years. An important issue is determining immediate vs long-term risk regarding treatment effectiveness and durability. This issue emphasizes the importance of long-term follow-up in patients after surgical and endovascular procedures.

Natural history and general management of unruptured intracranial aneurysms

After an aneurysmal subarachnoid hemorrhage, nearly half of the patients die and the half who survive suffer from irreversible cerebral damage. With increasing use of noninvasive neuroimaging techniques (for example, magnetic resonance and computerized tomography angiography), more unruptured cerebral aneurysms are found. To understand the prevalence of unruptured aneurysms in the general population, along with the risks of aneurysm formation, data on growth and rupture rates are crucial. The risk of rupture in aneurysms smaller than 10 mm is still not quite clear without a population-based prospective study. Nevertheless, a 0.5 to 2% annual risk may be a reasonable estimate. Growing aneurysms and those larger than 10 mm carry a higher rate of rupture. The management of an unruptured intracranial aneurysm should be based on a thorough understanding of the natural history of these lesions and careful evaluation of the morbidity and mortality levels associated with each treatment option.

Surgical Treatment of Unruptured Intracranial Aneurysms Over the Past 22 Years

The medical records of 312 patients who underwent surgical intervention for unruptured intracranial aneurysm by the same neurosurgeon between April 1979 and December 2000 were analyzed retrospectively to clarify the complexities of this treatment. Patients were divided into Groups I (earlier) to IV (later) according to the date of surgery. Outcome was evaluated as no change after surgery, transient postoperative deterioration (TD), or permanent deterioration (PD). Operative period, background disease, age, aneurysm location and size, postoperative results, and affecting factors were investigated. The overall rate of PD was 5%, including one death (0.3%), and the overall rate of TD was 11%. Cases of middle cerebral artery aneurysm and small aneurysm with diameters less than 10 mm in all locations showed favorable outcomes. There were no significant differences in operative results and period except the lower incidence of TD in Group IV. Surgical outcome was significantly correlated with aneurysm size. Vertebrobasilar artery aneurysm was associated with worse operative results. Most of the causes of PD were related to operative procedures, mainly perforator injury and general complications. Unruptured aneurysm can be treated safely, especially in cases of middle cerebral artery aneurysm and small aneurysm of less than 10 mm diameter in all locations. Larger aneurysms and vertebrobasilar artery aneurysm should be treated by experienced neurosurgeons.

Investigation of the surgically treated and untreated unruptured cerebral aneurysms of the anterior circulation

BACKGROUND

The natural history of unruptured cerebral aneurysms and the surgical risks are modified by several factors including size, location, and presence of subarachnoid hemorrhage (SAH). The main confusion arises because the backgrounds of the past reports describing the natural history or the surgical complication of unruptured cerebral aneurysms were different. The present study aimed to adjust the backgrounds and investigate the surgical indication with close monitoring of both surgically treated and untreated unruptured cerebral aneurysms.

METHODS

In the past 9 years, 201 patients who had unruptured anterior circulation aneurysms were monitored. The decision of the operation was not randomized. The patients were divided into three subgroups by the size of the aneurysms (small group: below 5 mm, medium group: between 5 and 15 mm, large group: over 15 mm). In both surgically untreated and treated patients, overall mortality and morbidity corresponding to Rankin score II or worse was counted as unruptured aneurysm related event. The ratio of event free was compared between surgically treated and untreated patients using Log-rank test.

RESULTS

In untreated patients, SAH was noted in 1 in the small group and 4 in the medium group. The annual rupture rate of the medium group was 12 times higher than that of the small group. In surgically treated patients, overall mortality and morbidity of the surgery was 2.3% in the small group, 3.6% in the medium group, and 20% in the large group. One surgically treated patient had SAH because of regrowth of aneurysm. When ratio of event free was compared, no significant advantage of surgery was noted in the small group and in all of the patients. However, the benefit of surgery was significant in the medium group (Log-rank p = 0.0189).

CONCLUSIONS

The present results indicated that prophylactic surgery has a benefit for the medium-size aneurysms (5-15 mm) of the anterior circulation. For large aneurysms, individual investigation is necessary because of the variety of surgical difficulties, and the complex symptoms because of rupture and the mass effect as well as cerebral embolism. In small aneurysms, careful observation may be a reasonable choice unless the aneurysm is at a specially high risk of rupture.

Unruptured large intracranial aneurysms in patients with transient cerebral ischemic episodes

This report analyzes the treatment of six patients with transient cerebral ischemic episodes in combination with large unruptured aneurysm. Priority treatment of the symptomatic lesions had to be delayed in five cases because the large aneurysms were ipsilateral to stenoses of the internal carotid artery. The hemodynamic effect of surgery on the compromised cerebral circulation was pre-examined with digital subtraction angiography and technetium-99m ((99m)Tc) single photon emission computed tomography. The data were correlated to aneurysm location and anatomical territory of the transient ischemic episodes. Only one patient showing a severe carotid stenosis contralateral to the large aneurysm, with decreased technetium uptake in the symptomatic hemisphere, required surgical correction of the stenosis first. In five patients, areas of reduced (99m)Tc uptake were mostly found within vascular boundary zones with angiographically verified effective collateral circulation. Clipping of the large aneurysms in these patients ipsilaterally to the stenotic lesion or on the anterior communicating artery as first option did not substantially increase the risk of subsequent stroke.

Natural history of unruptured intracranial aneurysms: risks for aneurysm formation, growth, and rupture

Several studies concerning risk factors for SAH and for subsequent rupture of an unruptured aneurysm have been published, but not risk factor studies for formation and growth rate of aneurysms. Because less than half of all aneurysms ever rupture, it is essential to know risk factors separately both for aneurysm formation and for its growth. Before 1979, unruptured aneurysms were not operated on in Helsinki. Recently, the results of risk factors for rupture of unruptured aneurysms of 142 patients (131 with a prior SAH) have been published. 89 were followed with conventional and/or 3D CT angiography, or at autopsy to define risk factors for aneurysm formation and growth. During 2575 person-years, 33 of the 142 patients (23%) suffered SAH, resulting in an annual incidence of 1.3% (95% CI, 0.9-1.7%). The cumulative rate of bleeding was 10.5% (95% CI, 5.3-15.8%) at 10 years, and 30.3% (21.1-39.6%) at 30 years. Independent risk factors for rupture were cigarette smoking (time-dependent relative risk, 3.04; 95% CI, 1.21-7.66), and size of aneurysm (1.14 per mm; 1.01-1.30) after adjustment for age, aneurysm group, and hypertension. In addition, current cigarette smoking at end of follow-up (age-adjusted odds ratio, 3.92; 95% CI, 1.29-11.93) and female gender 3.36 (1.11-10.22) were the only independent risk factors for aneurysm growth of > or = 1 mm but only current smoking (3.48, 1.14-10.64) was a risk factor for growth of > or = 3 mm. Probability of de novo aneurysm formation was 0.84% per year (95% CI, 0.47-1.37%). Female gender (adjusted odds ratio, 4.73; 95% CI, 1.16-19.38) and current smoking (4.07, 1.09-15.15) were the only significant (p < 0.05) independent risk factors for de novo aneurysm formation. Cessation of smoking is very important for these patients. It is recommended that unruptured aneurysms be operated on irrespective of their size and of patients' smoking status, in people aged < 50 to 60 years.

Treatment of incidental unruptured aneurysms

The most important task for an effective way of SAH prevention is to estimate the rupture risk of unruptured intracranial aneurysms (UIAs) and to reduce the operative risk for clipping. A multi-center study on the treatment of UIAs was organized in 1999, supported by the Japanese Ministry of Health and Welfare. In five Japanese National Hospitals, all UIAs were registered and analyzed. In this study, we investigated the management outcome in 146 patients with asymptomatic incidentally discovered aneurysms to evaluate the benefit of preventive surgery and conservative treatment. Ninety-seven patients underwent surgery and three patients (3.1%) became moderately or severely disabled after surgery. There was no mortality after surgery or endovascular therapy. Among the 39 patients who underwent conservative therapy, four (10.3%) suffered from subsequent aneurysm rupture. Radical treatment should be considered for the patients with incidental unruptured aneurysms.

Unruptured intracranial aneurysms in patients with transient cerebral ischemic episodes. Optional managements and literature review

Clinical experience about the management of patients with an unruptured intracranial aneurysm (UIA) presenting transient cerebral ischemic attacks (TIAs) is usually restricted to a few case reports. Some authors assume tha it is safe to perform an endarterectomy without acutely increasing the risk of aneurysm rupture while others reported a post-operative aneurysmal bleeding even for aneurysms smaller than 10 mm between some days and several months after endarterectomy. The aim of this paper is to analyse the factors involved in the particular ischemic episodes, the examination methods to be employed, and the optional management for each individual case on a literature review and own experience-based data.

Aneurysm observation versus intervention: a literature review

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating illness that affects persons at the peaks of their lives. The 1990s witnessed rapid growth in noninvasive vascular imaging technologies, which allowed safe diagnosis of unruptured saccular intracranial aneurysms. Presently, it is unclear who will benefit from screening. Mass screening is neither feasible nor cost-effective. The current literature suggests that persons in a family with two or more relatives with a history of SAH are most likely to benefit from screening. Individuals with a history of SAH, with aneurysms greater than 10 mm in diameter or with symptomatic aneurysms are clearly at increased risk for SAH. These aneurysms should be treated, though the method of treatment remains open to question. Treatment of older patients or those with smaller aneurysms has been modeled by decision analysis, but has yet to be verified in a prospective clinical trial. Future directions for aneurysm management are explored.

Guglielmi detachable coil embolization of posterior circulation aneurysms: a systematic review of the literature

BACKGROUND

Early multicenter trials of Guglielmi detachable coil embolization of posterior circulations aneurysms have been followed by the publication of numerous single-center experiences. Summary of Review- We performed a MEDLINE literature search and extracted data from single-center reports containing at least 10 posterior circulation aneurysms. Twelve reports (495 aneurysms) were specific to the posterior circulation. Eighty-two percent of aneurysms arose near the basilar apex. Eighty-one percent of patients harbored unruptured aneurysms or presented in good clinical condition. Sixty-three percent of lesions were small, and 41% exhibited a narrow neck. Coil deposition was achieved in 97.6% of cases. Procedural complication and morbidity rates were 12.5% and 5.1%, respectively. Procedural and 30-day mortality rates were 1.4% and 6.7%, respectively. Complete aneurysm occlusion was achieved in 47.6%, near-complete occlusion (90% to 99%) in 43.4%, and incomplete occlusion in 9.0% of cases. There were a total of 52 recurrences (22.2%) in a subset of 234 evaluable patients. Ninety-two percent of these aneurysms exhibited wide necks. The annual risk of subarachnoid hemorrhage after embolization was 0.8%. Eighty-five percent of patients achieved functional independence, while only 5.3% lived dependent lifestyles. The overall mortality rate was 9.8%.

CONCLUSIONS

The published literature approximates a large series of basilar apex aneurysms. Embolization is moderately effective in completely excluding an aneurysm from the posterior circulation. The incidence of recurrence in wide-neck aneurysms and incompletely coiled aneurysms is substantial. Coil embolization is effective in preventing early rebleeding. Its role in the treatment of unruptured aneurysms remains unclear.

Diffusion-enhanced visualization and quantification of vascular anomalies in three-dimensional rotational angiography: Results of an in-vitro evaluation

Three-dimensional rotational angiography (3DRA) is a new and promising technique for obtaining high-resolution isotropic 3D images of vascular structures. However, due to the relatively high noise level and the presence of other background structures in clinical 3DRA images, noise reduction is inevitable. In this paper, we evaluate a number of linear and nonlinear diffusion techniques for this purpose. Specifically, we analyze the effects of these techniques on the threshold-based visualization and quantification of vascular anomalies in 3DRA images. The results of in-vitro experiments indicate that edge-enhancing anisotropic diffusion filtering is most suitable: the increase in the user-dependency of visualizations and quantifications is considerably less with this technique compared to linear filtering techniques, and it is better at reducing noise near edges than isotropic nonlinear diffusion. However, in view of the memory and computation-time requirements of this technique, the latter scheme may be considered a useful alternative.

Identifying patients at risk for postprocedural morbidity after treatment of incidental intracranial aneurysms: the role of aneurysm size and location

Object

A decision to treat incidental intracranial aneurysms (IIAs) relies on understanding the risks of treatment and weighing them against the those of aneurysm rupture. Whereas the natural history of IIAs is currently being studied, the risks associated with treating IIAs and factors associated with poor outcome need to be clearly established.

Methods

In a consecutive series of 125 patients, 160 IIAs were treated either surgically (152 cases) or endovascularly (eight cases). Postprocedural morbidity was defined as a new neurological deficit associated with a score greater than or equal to 3 on the modified Rankin Scale or a score of less than 24 on the Mini-Mental Status Examination. Logistic regression analysis was used to identify predictors of postprocedural morbidity from retrospectively collected data on demographic, clinical, and radiographic characteristics.

Treatment of IIAs was not associated with any mortality and was associated with postprocedural morbidity in 17 (13.6%) of 125 patients (early outcome) and eight (6.4%) of patients (late outcome). In the logistic-regression model, treatment of aneurysms (≥13 mm) and posterior circulation aneurysms were independently associated with postprocedural morbidity. In patients in whom postprocedural neurological deficits developed, 12 (70.6%) of 17 and four (23.5%) of 17 patients harbored aneurysms with broad or calcified necks, respectively. Age, comorbidities, multiple aneurysms, specific aneurysm location, and history of subarachnoid hemorrhage related to a different aneurysm were not significantly associated with poor outcome.

Conclusions

The authors found that IIAs can be safely and effectively treated without causing mortality and with a lower morbidity rate than previously reported. A combination of radiographic variables may be helpful in identifying patients at risk for postprocedural morbidity.

Surgical management of unruptured aneurysms: prognostic indicators

BACKGROUND

The treatment of unruptured aneurysms (UA) remains controversial. Therefore, it has become necessary to define various prognostic indicators in the surgical treatment of unruptured aneurysms not associated with previously ruptured aneurysms.

METHODS

During a 6-year period, 78 unruptured aneurysms were managed. The results of management were retrospectively reviewed to define the prognostic indicators.

RESULTS

There were 104 patients with unruptured aneurysms who underwent surgical treatment. Seventy-five patients without previous subarachnoid hemorrhage (SAH) were selected for data analysis. Eighty-seven percent of the aneurysms were on the anterior circulation. The most common location was the middle cerebral artery (MCA) followed by the posterior communicating artery (PCom), ophthalmic artery, and anterior communicating artery (ACom). Six percent were found on the basilar artery. The mean size of aneurysms was 12.5 mm (range = 3-30 mm, SD = 7.4). At surgery, rupture of the aneurysm was encountered in eight cases with temporary control of the parent vessel being required in 31 procedures. In four cases, intraoperative angiography warranted clip reapplication. The Glasgow Outcome Scale (GOS) was used as an outcome measure. Surgical treatment resulted in good outcome (GOS 1) in 87% and 10.7% had fair outcome; 2.3% were in GOS 3 (severe disability) at 6 month follow-up. There was no mortality. Logistic regression identified significant relationships between GOS and intraoperative rupture (p < 0.0002), rupture and size (p < 0.003), and size and age (p < 0.01).

CONCLUSIONS

Large size aneurysms were associated with intraoperative rupture, which had a strong correlation with poor outcome. Increased age showed a linear relationship with the size of the aneurysm. Overall results of treatment for UA are gratifying. There was no mortality. Early diagnosis and surgical extirpation of UA may reduce both intraoperative difficulties as well as poor outcome probability.