Progress in cerebrovascular disease. Management of cerebral aneurysm

Tailoring fenestrated aneurysm clips intraoperatively: Instant solution for a difficult problem

The anterior communicating artery (AcoA) aneurysms represent the most complex aneurysms of the anterior circulation. For years, surgical challenges including the intricate anatomy and narrow surgical corridor have been overcome using supplementary techniques including extended craniotomies, wide opening of the cisterns, gyrus rectus resection and special clips like fenestrated clips. However, imaginative solutions such as intraoperative clip modification may be inevitable in particular cases for safe clipping. We retrospectively analyzed clinical records of two patients who required clip modification intraoperatively. Case #1 underwent microsurgical clipping of a ruptured, 4-mm AcoA aneurysm. Unfortunately, given the short distance between the two A2s, it was not possible to clip the aneurysm without a compromise to the contralateral A2 with the available shortest 3mm-fenestrated clip. We then used the clip modification technique intraoperatively by shortening the clip tips with mesh-plaque cutter and smoothening the remaining sharp ends using cautery sanding. Eventually, the aneurysm was clipped successfully with the modified-fenestrated clip. Post-clipping imagings confirmed complete occlusion of the aneurysm and patency of parent arteries. Case 2# underwent microsurgical clipping for a ruptured, 1-mm AcoA aneurysm. Like Case 1#, the initial clipping attempt with the available shortest 4mm-fenestrated clip failed given the excessive length of the tips. The patient, thus, required clip modification as described above. The aneurysm was then clipped successfully using the modified-fenestrated clip, protecting bilateral A2s. Post-clipping imagings demonstrated patency of parent arteries with no residual aneurysm filling. Clip modification seems to be an effective option in clipping the AcoA aneurysms when available clips are too long to secure them safely.

Surgical outcomes of patients with unruptured anterior vs. inferior circulation aneurysms: A meta‑analysis

The treatment option for unruptured intracranial aneurysms (UIAs) depends on their natural history-related risk of rupture vs. the risk of surgical management. The present meta-analysis sought to assess the association between the surgical outcomes of anterior and posterior circulation UIAs. The present study investigated the comparative articles involving the surgical treatment of anterior vs. posterior circulation UIAs through electronic databases, including the Cochrane Library, PubMed (1980 to March, 2023), Medline (1980 to March, 2023) and EMBASE (1980 to March, 2023). Quoting all exclusion and inclusion criteria, nine articles finally remained for statistical analysis. The entire number of patients included in these nine articles was 3,253 (2,662 in the anterior and 591 in the posterior circulation UIAs group). The present meta-analysis proposes that the surgical treatment of anterior circulation UIAs is associated with better outcomes compared with the surgical management of posterior circulation UIAs.

Enhance Safety in Aneurysm Surgery: Strategies for Prevention of Intraoperative Vascular Complications

Complications during surgery for intracranial aneurysms can be devastating. Notorious pitfalls include premature rupture, parent vessel occlusion, local cerebral injury and brain contusion, and incomplete neck obliteration. These unfavorable intraoperative events can result in major neurological deficits with permanent morbidity and even mortality. Herein, the author highlights the relevant surgical strategies used in his daily practice of aneurysm surgery (e.g., aneurysm clipping with adenosine-induced temporary cardiac arrest), application of which may help prevent vascular complications and enhance surgical safety through reduction of the associated risks, thus allowing improvement of postoperative outcomes. Overall, all described methods and techniques should be considered as small pieces in the complex puzzle of prevention of vascular complications during aneurysm surgery.

Microsurgery of Giant Intracranial Aneurysm: A Single Institution Outcome Study

Background

Giant intracranial aneurysms (GIAs) are treacherous lesions and in spite of the many advances, endovascular therapy (EVT) of GIAs is challenging.

Objective

A retrospective analysis of our results with microsurgery of GIAs is presented to examine the role of microsurgery in the current trend of EVT.

Materials and Methods

Between 1996 and 2019, 134 patients with 147 GIAs had microsurgery by the senior author in a single institute. The medical and imaging records for all the patients were reviewed. The patient outcome was determined by modified Rankin scale (mRS); ≤3 was considered as a good outcome. Statistical analysis was done using the SPSS program and odds ratios and their 95% confidence intervals were computed; a probability value of < 0.05 was considered significant.

Results

There were 123 aneurysms (83.7%) in the anterior circulation and 24 aneurysms (16.3%) in the posterior circulation. Overall 103 out of 134 (76.8%) patients had a good outcome postoperatively. Good preoperative mRS score (≤3) had an overall good prognosis in the postoperative period and was statistically significant (P = 0.000, odds ratio: 0.036, 95% CI: 0.008-0.171). Presence of subarachnoid hemorrhage (SAH) was also statistically significant for good outcome (P = 0.04, odds ratio: 2.898, 95% CI: 1.051-7.991), but age was not a significant prognostic factor. Mortality within 30 days of treatment was 4.47%.

Conclusion

GIAs need treatment because of their dismal natural history. Results of microsurgical treatment by a single surgeon of the large current series compare well with the results of EVT and justifies pursuing microsurgery for GIAs.

Remarkable shrinkage of a thrombosed giant aneurysm by stent-assisted jam-packed coil embolization

Background:

Large and giant aneurysms are known to involve intra-aneurysmal thrombosis and present a poor prognosis because of compression of the surrounding brain tissue with enlargement of the aneurysm. These aneurysms are difficult to cure by endovascular treatment due to involvement of the vasa vasorum in their pathology. We report this technical note to describe stent-assisted jam-packed coil embolization for the treatment of a giant thrombosed aneurysm.

Case Description:

A 62-year-old man presented with right homonymous hemianopsia, and magnetic resonance imaging (MRI) showed a giant thrombosed aneurysm with poor wall contrast enhancement, which indicates little involvement of the vasa vasorum, at the terminal part of the left internal carotid artery. To block blood flow into the aneurysmal dome, stent-assisted “jam-packed” coil embolization was performed. For this, a braided stent was shortened to enhance metal coverage ratio and tight aneurysmal coil packing was performed using a hydrogel coil. Our technique resulted in complete obliteration of the aneurysm, and MRI performed 1 year later showed remarkable shrinkage of the aneurysm dome.

Conclusion:

Stent-assisted jam-packed coil embolization technique might be effective in shrinking the dome of giant thrombosed aneurysms with poor wall contrast enhancement.

Predictors of Periprocedural Complications and Angiographic Outcomes of Endovascular Therapy for Large and Giant Intracranial Posterior Circulation Aneurysms

OBJECTIVE

To explore the predictors of periprocedural complications and angiographic outcomes in large and giant intracranial posterior circulation aneurysms after endovascular treatment.

METHODS

Data from 99 patients with 103 large (≥10 mm; n = 94) and giant (>25 mm; n = 9) posterior circulation aneurysms treated with endovascular therapy at a single center were retrospectively analyzed. The treatment procedures included endovascular trapping (n = 15), coiling (n = 6), stent only (n = 10), stent-assisted coiling (n = 48), and pipeline embolization device (PED; n = 24). The outcome endpoints were the number of periprocedural complications and number of complete occlusions without any complication.

RESULTS

Multivariate analysis revealed that intradural vertebral aneurysms (P = 0.041) and aneurysms ≤25 mm (P = 0.042) were associated with low periprocedural complication rates after endovascular therapy. Aneurysms not involving side branches (P = 0.024) and intradural vertebral aneurysms (P = 0.032) were predictors of complete aneurysm obliteration. No statistically significant differences were found in aneurysmal complete obliteration (P = 0.119) or periprocedural complications (P = 0.248) between a PED and traditional stent and coiling. Additionally, aneurysms not involving side branches (P = 0.030), intradural vertebral artery aneurysms (P = 0.003), and aneurysms treated with a PED (P = 0.020) were more likely to achieve complete occlusion over time.

CONCLUSIONS

Aneurysm location, aneurysm size, and side branch involvement were predictors of periprocedural complications and angiographic outcomes of endovascular therapy for large and giant intracranial posterior circulation aneurysms. PED use provided no advantages compared with traditional stent and coiling in aneurysmal occlusion rates and periprocedural complications. Large case-control and long-term follow-up studies are needed to further explore the predictors of complications and angiographic outcomes and optimal treatment options for these aneurysms.

Epileptic seizures as the first manifestation of the frontoparietal arteriovenous malformation of the brain

Abstract: Introduction: Arteriovenous malformations of the brain include a group of congenital disorders in the early development of arterial-venous blood vessels of the brain. Their clinical presentation is most common in the form of a brain hemorrhage, epileptic seizures, and headaches. Case report: We showed a man who at the age of 28 early in the morning after breakfast had the first generalized tonic-clonic seizure. After the second unprovoked epileptic seizure, antiepileptic therapy was introduced. The brain scanner showed the existence of arteriovenous malformations in the right frontoparietal region. As the size of the malformation was less than 30mm, it was decided that the patient should be treated with Gamma knife radiosurgery. After the successful radiosurgery together with the antiepileptic drugs treatment, the patient is in a stable 1.5 yearlong remission of epileptic seizures without neurological failures. Conclusion: Epileptic seizures can be the initial clinical manifestations of arteriovenous malformations of the brain. With an early diagnosis, adequate antiepileptic drugs therapy and neurosurgery, radiosurgery (Gamma Knife), which is often necessary, many symptomatic epilepsies enter a stable remission of epileptic seizures.

Posterior Fossa Craniectomy with Endovascular Therapy of Giant Fusiform Basilar Artery Aneurysms: A New Approach to Consider?

BACKGROUND

The prognosis of unruptured giant basilar artery (BA) aneurysms is very poor. No treatment has shown efficacy in survival. This pilot case-control study examines the overall survival (OS) benefit of combined surgical and endovascular management of giant BA aneurysms.

METHODS

Combined treatment including posterior fossa craniectomy followed by endovascular treatment was performed in 3 patients with giant BA aneurysms. OS of the 3 patients was compared with a control group of 6 patients (ratio 1:2) treated with the endovascular procedure only.

RESULTS

The mean survival time was 32.6 months in the craniectomy group (SD 9.01, 95% confidence interval [14.9, 50.3]) and 3.5 months in the control group (SD = 2.08, 95% confidence interval [0.001, 7.6]; Mantel-Cox test P < 0.04). At mean follow-up of 36.5 months (SD 10.2), 2 of 3 patients had a favorable outcome with a Glasgow Outcome Scale score of 5. Univariate analysis determined that women had a statistically higher OS than men (33.7 months vs. 3.058 months for men; log-rank test P = 0.011). A similar outcome was obtained in the presence of a circulating posterior communicating artery (P = 0.03) and in the presence of an endovascular right vertebral artery occlusion (P = 0.022).

CONCLUSIONS

Our study suggests that preventive posterior fossa craniectomy increases significantly OS of patients with giant BA aneurysms.

L'angiografia a risonanza magnetica nello studio del circolo cerebrale

Le recenti acquisizioni tecniche hanno rapidamente reso l'angiografia RM una delle più importanti indagini vascolari non invasive. Scopo della nostra ricerca è verificare l'applicabilità clinica dell'angiografia RM e valutare la sua accuratezza diagnostica nei confronti dell'angiografia per via arteriosa (angiografia invasiva) nello studio degli aneurismi del circolo cerebrale. Sono stati esaminati con «Angiografia Tridimensionale a Risonanza Magnetica», basata sul fenomeno del «tempo di volo», 23 pazienti, con un numero complessivo di 25 aneurismi, di cui 4 con dimensioni superiori ad 1,5 cm (macroaneurismi). In tutti i casi sono state utilizzate sequenze ad «Eco di Gradiente» 3D con compensazione per il flusso, mentre nei 4 casi di macroaneurisma sono state impiegate anche sequenze ad «Eco di Gradiente» 2D «single slice». In tutti i pazienti l'angiografia RM è stata associata ad una valutazione con sequenze Spin-Echo del parenchima cerebrale allo scopo di documentare l'eventuale presenza di aree di sofferenza parenchimale. L'angiografia invasiva per via arteriosa era disponibile per il confronto in tutti i casi. 18 pazienti sono stati sottoposti ad intervento chirurgico di «legatura» dell'aneurisma. Nei confonti dell'angiografia invasiva la sensibilità dell'angiografia RM è risultata complessivamente dell' 88% e la specificità del 90%, con un'accuratezza diagnostica dell'89%. Lo studio dimostra come l'angiografia RM, basata sul fenomeno del «tempo di volo», sia in grado di identificare aneurismi di dimensioni fino a 3mm e possa essere utilmente impiegata nella valutazione clinica dell'encefalo come fonte di informazioni supplementari sul circolo cerebrale.

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.

Neuroradiologic Diagnosis of Minor Leak prior to Major SAH: Diagnosis by T1-FLAIR Mismatch

BACKGROUND AND PURPOSE

In major SAH, the only method to diagnose a preceding minor leak is to ascertain the presence of a warning headache by interview; however, poor clinical condition and recall bias can cause inaccuracy. We devised a neuroradiologic method to diagnose previous minor leak in patients with SAH and attempted to determine whether warning (sentinel) headaches were associated with minor leaks before major SAH.

MATERIALS AND METHODS

We retrospectively evaluated 127 patients who were admitted with SAH within 48 hours of ictus. Previous minor leak before major SAH was defined as T1WI-detected clearly bright hyperintense subarachnoid blood accompanied by SAH blood on FLAIR images that was distributed over a larger area than bright hyperintense subarachnoid blood on T1WI (T1-FLAIR mismatch).

RESULTS

The incidence of warning headache before SAH was 11.0% (14 of 127 patients, determined by interview). The incidence of T1-FLAIR mismatch (neuroradiologic diagnosis of minor leak before major SAH) was 33.9% (43 of 127 patients). Of the 14 patients with warning headache, 13 had a minor leak diagnosed by T1-FLAIR mismatch at the time of admission. Variables identified by multivariate analysis as significantly associated with minor leak diagnosed by T1-FLAIR mismatch included 80 years of age or older, rebleeding after admission, intracerebral hemorrhage on CT, and mRS scores of 3-6.

CONCLUSIONS

We conclude that warning headaches diagnosed by interview are not a product of recall bias but are the result of actual leaks from aneurysms.

Multiple reimplantation technique for treatment of complex giant aneurysms of the middle cerebral artery: technical note

BACKGROUND

Giant middle cerebral artery (MCA) aneurysms are among the most challenging neurovascular lesions, especially when the M2 and M3 branches are incorporated into the aneurysm. Here we report on two cases with complex MCA aneurysms, in which double and triple arterial reimplantation of the efferent vessels into a saphenous vein graft (SVG) was applied to reconstruct the MCA tree, allowing final trapping of the aneurysm.

METHODS

In the first case, a 41-year-old woman presented with a partially thrombosed giant MCA aneurysm including three efferent branches. Two superior trunks were disconnected and reimplanted onto an SVG fed by the external carotid artery (ECA). Following anastomosis between the SVG and the inferior trunk, the aneurysm was trapped. The second case is a 67-year-old man with recurrent giant MCA aneurysm incorporating two efferent M2 branches. First, the superior trunk was reimplanted onto an SVG, then the SVG was anastomosed to the inferior trunk. Finally the afferent M1 was clipped. Intraoperative indocyanine green (ICG) videoangiography (FLOW 800) was used for studying bypass patency.

RESULTS

In both cases, successful bypass patency was demonstrated by ICG videoangiography. Postoperative digital subtraction angiography (DSA) confirmed bypass patency. The first case was discharged without any neurological deficit. The second case suffered from bleeding due to refilling of the aneurysm via the inferior M2. An additional clip was placed on the inferior M2 in a second step. The patient was discharged with weakness of the left arm.

CONCLUSION

Reconstructing an MCA bifurcation or trifurcation combining multiple arterial reimplantation is effective for treatment of selective cases of complex MCA aneurysms.

Timing of aneurysm treatment after subarachnoid hemorrhage: relationship with delayed cerebral ischemia and poor outcome

BACKGROUND AND PURPOSE

The ideal timing of coiling or clipping after aneurysmal subarachnoid hemorrhage is unknown. Within the International Subarachnoid Aneurysm Trial we assessed differences in incidence of delayed cerebral ischemia and clinical outcome between different timings of treatment.

METHODS

The treated 2106 patients randomized to coiling or clipping were divided into 4 categories: treatment <2 days, on days 3 to 4, on days 5 to 10, and >10 days after the hemorrhage. ORs with 95% CI were calculated with logistic regression analysis for delayed cerebral ischemia, poor outcome at 2 months, and 1 year for the different timing categories, with treatment <2 days as reference. Analyses were performed for all patients, and for coiled and clipped patients separately, and were adjusted for baseline characteristics.

RESULTS

Adjusted ORs of delayed cerebral ischemia for treatment on days 5 to 10 were 1.18 (95% CI, 0.91-1.53) for all patients, 1.68 (95% CI, 1.17-2.43) after coiling, and 0.79 (95% CI, 0.54-1.16) after clipping. ORs for poor outcome at 2 months were 1.16 (95% CI, 0.89-1.50) for treatment (clipping and coiling combined) at 3 to 4 days, 1.39 (95% CI, 1.08-1.80) for treatment at 5 to 10 days, and 1.84 (95% CI, 1.36-2.51) for treatment >10 days. ORs for coiled and clipped patients separately were in the same range. Results for outcome at 1 year were similar.

CONCLUSIONS

Our results support the current practice for early aneurysm treatment in subarachnoid hemorrhage patients. The risk for poor outcome was highest when treatment was performed after day 10; postponing treatment in patients who are eligible for treatment between days 5 to 10 after subarachnoid hemorrhage is not recommended.

Clip ligation of unruptured intracranial aneurysms: a prospective midterm outcome study

BACKGROUND

We conducted a prospective study to investigate the clinical and radiological outcome in a surgical case series of 176 patients with 203 unruptured intracranial aneurysms (UIA).

METHODS

The success of aneurysm obliteration was assessed within 2 weeks after surgery by digital subtraction angiography (DSA). Patients also underwent angiography 5 years after surgery. Clinical outcomes were assessed using the modified Rankin Scale (mRS). All predictors of poor surgical outcomes were assessed using an exact logistic regression.

RESULTS

Overall, 83 % of the patients had a good outcome (mRS score 0 or 1); 10.8 % of the patients had a slight disability (mRS score 2), and 6.2 % of the patients had a moderate or moderate-severe disability (mRS score 3 or 4). The mortality rate was 0 % overall. The most important predictors of outcome were presence of history of ischemic cerebrovascular disease and postoperative stroke. Complete aneurysm occlusion was achieved in 93.5 % of all aneurysms. Sixty percent of treated aneurysms were checked with late follow-up DSA. No cases of hemorrhage from a surgically obliterated UIA were documented in this series during the 7.3 ± 1.4 (SD)-year follow-up period.

CONCLUSIONS

If patients are carefully selected and individually assigned to their optimum treatment modality, IUAs can be obliterated by surgery with a low percentage of unfavorable outcomes.

Predictors of Clinical and Angiographic Outcome After Surgical or Endovascular Therapy of Very Large and Giant Intracranial Aneurysms

BACKGROUND:

Risk factors for poor outcome in the treatment of very large (≥20-24 mm) and giant (≥25 mm) intracranial aneurysms remain incompletely defined.

OBJECTIVE:

To present an aggregate clinical series detailing a 24-year experience with very large and giant aneurysms to identify and assess the relative importance of various patient, aneurysm, and treatment-specific characteristics associated with clinical and angiographic outcomes.

METHODS:

The authors retrospectively identified 184 aneurysms measuring 20 mm or larger (85 very large, 99 giant) treated at Stanford University Medical Center between 1984 and 2008. Clinical data including age, presentation, and modified Rankin Scale (mRS) score were recorded, along with aneurysm size, location, and morphology. Type of treatment was noted and clinical outcome measured using the mRS score at final follow-up. Angiographic outcomes were completely occluded, occluded with residual neck, partly obliterated, or patent with modified flow.

RESULTS:

After multivariate analysis, risk factors for poor clinical outcome included a baseline mRS score of 2 or higher (odds ratio [OR], 0.23; 95% confidence interval [CI]: 0.08-0.66; P = .01), aneurysm size of 25 mm or larger (OR, 3.32; 95% CI: 1.51-7.28; P &lt; .01), and posterior circulation location (OR, 0.18; 95% CI: 0.07-0.43; P &lt; .01). Risk factors for incomplete angiographic obliteration included fusiform morphology (OR, 0.25; 95% CI: 0.10-0.66; P #x003C; .01), posterior circulation location (OR, 0.33; 95% CI: 0.13-0.83; P = .02), and endovascular treatment (OR, 0.14; 95% CI: 0.06-0.32; P &lt; .01). Patients with incompletely occluded aneurysms experienced higher rates of posttreatment subarachnoid hemorrhage and had increased mortality compared with those with completely obliterated aneurysms.

CONCLUSION:

Our results suggest that patients with poor baseline functional status, giant aneurysms, and aneurysms in the posterior circulation had a significantly higher proportion of poor outcomes at final follow-up. Fusiform morphology, posterior circulation location, and endovascular treatment were risk factors for incompletely obliterated aneurysms.

Fenestrated aneurysm clips in the surgical management of anterior communicating artery aneurysms: operative techniques and strategy

Object

Aneurysms of the anterior communicating artery (ACoA) can be a considerable challenge to treat surgically based on variations in the anatomy and morphological features of the ACoA complex. The fenestrated aneurysm clip can be a simple and practical tool in the operative management of ACoA aneurysms. The goal in this study was to characterize the particular surgical situations in which the use of a fenestrated clip facilitates the clip ligation of ACoA aneurysms.

Methods

The authors present their operative strategy and techniques for the use of fenestrated clips in the treatment of ACoA aneurysms.

Results

One hundred ninety-nine patients underwent surgical clipping of an ACoA aneurysm at the authors' institution between the years 1991 and 2008. Of these patients, fenestrated aneurysm clips were used in 20 cases (10%). The following structures were enclosed in the clip aperture: ipsilateral A2 artery, 12 patients (60%); ipsilateral A1 artery, 4 patients (20%); ipsilateral A1 artery plus recurrent artery of Heubner, 1 patient (5%); ACoA, 1 patient (5%); frontopolar artery, 1 patient (5%); and no structures, 1 patient (5%). Aneurysms approached from the left side more frequently required fenestrated clips than did right-sided aneurysms (80 vs 20%, p = 0.0073). In all cases, patency of the A2 vessels was confirmed on postoperative angiography. In 2 patients, small remnant aneurysm necks were identified on postoperative angiography.

Conclusions

The use of fenestrated aneurysm clips can minimize tedious and potentially dangerous dissection of adherent branch vessels, while maintaining the integrity of structures placed within the clip aperture. The ACoA aneurysms pointing in a superior direction are more likely to require clip fenestration around the A2 vessel, whereas those pointing in an inferior direction are more likely to require clip fenestration around the A1 vessel. The parallel approximation of the fenestrated clip blades makes them especially useful in the treatment of large or giant aneurysms.

[Aneurysmal subarachnoid hemorrhage. Significance and complications]

Despite substantial improvement in the management of patients with aneurysmal subarachnoid hemorrhage (SAH), including early aneurysm occlusion by endovascular techniques and surgical procedures, a significant percentage of patients with SAH still experience serious sequelae of neurological or cognitive deficits as a result of primary hemorrhage and/or secondary brain damage. Available neuromonitoring methods for early recognition of ischemia include, among others, measurement of brain tissue O(2) partial pressure, brain metabolism with microdialysis and monitoring of regional blood flow. The triple-H therapy (arterial hypertension, hypervolemia and hemodilution) is the treatment of choice of a symptomatic vasospasm and leads to an enduring recession of ischemic symptoms, if initiated early after the onset of a vasospasm-linked ischemic neurological deficit. Further promising therapy approaches are the administration of highly selective ET(A) receptor antagonists and intracisternal administration of vasodilators in depot form. This review summarizes the major neurological and non-neurological complications following aneurysm occlusion. Possible neuromonitoring techniques to improve diagnosis and therapy for treatment of symptomatic vasospasm as well as extracranial complications are discussed.

Balloon-assisted coil embolization of intracranial aneurysms: incidence, complications, and angiography results

Object

The aim of this study was to assess the incidence, indications, complications, and angiography results associated with balloon-assisted coil embolization (BACE) of intracranial aneurysms and to compare these factors with those for conventional coil embolization (CE).

Methods

Between 1995 and 2005, 827 intracranial aneurysms in 757 consecutive patients were packed with coils. Balloon-assisted coil embolization was used in 8.6% (71 of 827) of the coil insertion procedures and was more frequently used in large aneurysms, unruptured lesions, and those located on the vertebrobasilar system and carotid artery. Procedure-related complications leading to death or dependency were significantly higher in BACEs (14.1%) compared with those in CEs (3%). Packing densities and the results of 6-month follow-up angiography studies did not differ significantly between the two types of treatments. There was a strong trend for a higher retreatment rate in the aneurysms treated with BACE.

Conclusions

Balloon-assisted coil embolization of intracranial aneurysms is associated with a high complication rate and should only be used if conventional CE of these lesions is impossible or has failed and if anticipated surgical risks are too high. The BACE procedure does not improve the occlusion rates of the aneurysms on follow-up evaluation.

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.

Current treatment options for unruptured intracranial aneurysms

A patient with an unruptured intracranial aneurysm has three options: surgical clip placement, endovascular coil occlusion, and observation. The decision making about management of these lesions should be based on the risk of aneurysm rupture and the risks associated with surgical or endovascular intervention. For patients who require interventions, factors such as aneurysm recurrence rate, its location, surgical or endovascular accessibility, the patient's general medical condition, and the individual's treatment preference should be taken into account to determine the choice of therapies. Currently, a team approach by neurosurgeons and endovascular interventionists is recommended to evaluate each patient and to tailor the best treatment plan.

Les ruptures anévrismales intracrâniennes per-embolisation

OBJECTIVE

The purpose of this study is to determinate the frequency, causes, management and outcome of aneurysmal rupture occurring during embolization. We present our experience with this severe and feared complication.

METHODS

We retrospectively reviewed 314 acute cerebral aneurysms that were treated with endovascular coiling. These patients were identified and the management and outcomes were recorded. The literature was reviewed.

RESULTS

Six patients had an intraprocedural aneurysmal rupture. This complication occurred sporadically. Prevalence was 1.9%. Of these six, four were women and two were men. The mean age was 68 years (range: 43-74 years). Four aneurysms were located in the anterior circulation and two in the posterior circulation. Perforation occurred during microcatheterization of the aneurysm in one case and during coil deposition in five cases. In these five patients, aneurysmal rupture resulted from detachment of the first coil in three patients and detachment of the third and last coil in two patients. Hemodynamic changes were noted for one patient. The Glasgow Outcome Scale score at last follow-up examination was 1 in three patients and 3 in one patient (fair recovery). Mortality was 33% and morbidity was 16.7%.

CONCLUSION

Aneurysmal perforation during embolization is a rare event (1.8 to 4.4%). When perforation is recognized, embolization can be completed immediately with further coil deposition and reversal of anticoagulation therapy.

The impact of interventional neuroradiology on service in a neurosurgical unit

Endovascular treatment of cerebral aneurysms has rapidly evolved and has transformed neurosurgical practice. We evaluated the influence of an interventional neuroradiology service on cerebral aneurysm management. We performed a retrospective analysis of all aneurysms treated in our unit before and after the establishment of endovascular treatment. All patients (n = 248: 78M: 170F aged 10-78 years) who underwent aneurysm treatment between 1996 and 1999 were included in the analysis. Length of in-patient stay on neurosurgical ward, GOS at 6-month follow-up and complications of treatment were the factors chosen for the analysis. Definitive treatment was attempted in 306 of 374 aneurysms detected (203 surgical and 103 endovascular). During the last 2 years of the study period, 46% of all aneurysms were coiled. Endovascular treatment of ruptured aneurysms tended to be sooner than surgery, but in-patient stay following treatment was the same. No significant difference in GOS at 6-month follow-up was found (chi2 = 0.18). Coiling of unruptured aneurysms reduced in-patient stay when compared with surgery (t-test, p < 0.001), fewer complications occurred, but no difference in outcome was seen at follow up (chi2 = 1.09). Our data suggest that the long-term morbidity following subarachnoid haemorrhage is not related to treatment modality. Coiling is the preferred treatment for unruptured aneurysms. The GOS is insensitive to the detection of the perceived benefits of coiling. The increasing role of interventional neuroradiology has direct effects on many aspects of neurosurgical practice.

Pattern of cerebral aneurysms in Morocco: review of the concept of their rarity in developing countries: report of 200 cases

OBJECTIVE

Many neurosurgeons consider cerebral aneurysms to be rare in Africa and the Middle East. In this report, we describe the pattern of cerebral aneurysms in Morocco and call into question the idea of their rarity in developing countries. Our objective is to urge neurosurgeons in these areas to track them and to treat them under better conditions.

METHODS

We report a retrospective study of 200 patients with cerebral aneurysms admitted to our department between 1983 and 1999. The results of this study are supported by pertinent epidemiological surveys, anatomic studies on the incidence of cerebral aneurysms in Morocco, and analysis of the literature related to the epidemiology of aneurysms in developing countries.

RESULTS

The patients in our series ranged in age from 7 to 70 years (mean age, 52 yr), with a slight female predominance (52%). They presented with subarachnoid hemorrhage (173 patients), cranial nerve palsy (18 patients), or mass symptoms (9 patients). The delay between subarachnoid hemorrhage and admission ranged from 1 to 30 days (mean, 14 d). The aneurysm was located in the internal carotid artery in 42%, in the anterior communicating and anterior cerebral arteries in 28%, in the middle cerebral artery in 19%, and in the vertebrobasilar artery in 10%. Multiple aneurysms were encountered in 9% and giant aneurysms in 15.5%. Seventeen patients died before surgery (with vasospasm in 13 cases and rebleeding in 4 cases), and 19 died after surgery. Follow-up, ranging between 1 and 10 years, revealed good outcomes with complete recovery in 64.5% and recovery with major sequelae in 7%. Pre- and postoperative mortality represented 18%; there was no operative treatment and no follow-up in 11.5%.

CONCLUSION

Some data in this study (the delay between subarachnoid hemorrhage and admission, the high incidence of urban patients [80%], and the high rate of giant aneurysms) explain why many cases of ruptured aneurysms are not diagnosed. The analysis of our clinical series and the results of the epidemiological surveys show that the incidence has doubled every 5 years. These findings confirm that cerebral aneurysms are not rare in Morocco. A critical reading of the published articles claiming a low incidence of cerebral aneurysms in Africa, the Middle East, and Asia shows that this conclusion is not based on accurate and reliable statistical studies. Neurosurgeons in these regions should abandon this idea of rarity, and they should search for arterial cerebral aneurysms and develop the optimum conditions for the treatment of patients with aneurysms.

Volume-rendered helical computerized tomography angiography in the detection and characterization of intracranial aneurysms

OBJECT

The goal of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography in patients with intracranial aneurysms. The authors compared the abilities of CT angiography, digital subtraction (DS) angiography, and three-dimensional time-of-flight magnetic resonance (MR) angiography to characterize aneurysms.

METHODS

Helical CT angiography was performed in 45 patients with suspected intracranial aneurysms by using volume-rendered multiplanar reformatted (MPR) images. Digital subtraction angiography was performed using biplane angiography. These studies and those performed using MR angiography were interpreted in a blinded manner. Two neurosurgeons and two interventional neuroradiologists independently graded the utility of CT angiography with respect to aneurysm characterization. Fifty-five aneurysms were detected. Of these, 48 were evaluated for treatment. Computerized tomography angiography was judged to be superior to both DS and MR angiography in the evaluation of the arterial branching pattern at the aneurysm neck (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.007), aneurysm neck geometry (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.001), arterial branch incorporation (compared with DS angiography, p = 0.021, and with MR angiography, p = 0.001), mural thrombus (compared with DS angiography, p < 0.001), and mural calcification (compared with DS angiography, p < 0.001, and with MR angiography, p < 0.001). For surgical cases, CT angiography had a significant impact on treatment path (p = 0.001), operative approach (p = 0.001), and preoperative clip selection (p < 0.001). For endovascular cases, CT angiography had an impact on treatment path (p < 0.02), DS angiography study time (p = 0.01), contrast agent usage (p = 0.01), and coil selection (p = 0.02). Computerized tomography angiography provided unique information about 39 (81%) of 48 aneurysms, especially when compared with DS angiography (p = 0.003). The sensitivity and specificity of CT angiography compared with DS angiography was 1. The sensitivity and specificity of CT and DS angiography studies compared with operative findings were 0.98 and 1, respectively.

CONCLUSIONS

Computerized tomography angiography is equal to DS angiography in the detection and superior to DS angiography and MR angiography in the characterization of brain aneurysms. Information contained in volume-rendered CT angiography images had a significant impact on case management.

Risks of surgery for patients with unruptured intracranial aneurysms

BACKGROUND

With the widespread use of less invasive imaging tools, such as magnetic resonance angiography and computed tomographic angiography, unruptured cerebral aneurysms are found much more often than in the past. This retrospective study was undertaken to determine the risk factors for surgical intervention in a patient with an unruptured intracranial aneurysm.

METHODS

Over a 5-year period, 1,558 patients with intracranial aneurysms underwent surgery at our center. Of these, 310 patients (20%) with unruptured aneurysms were included in this study.

RESULTS

Out of 310 patients with unruptured aneurysms, 292 (95%) had a favorable outcome, and only one patient (0.3%) with a giant vertebral artery aneurysm died. Aneurysm size larger than 15 mm and location of the aneurysm in the posterior circulation were independent risk factors associated with less favorable outcomes. Patients with a single aneurysm had a better outcome than did patients with multiple aneurysms.

CONCLUSION

Our results support the contention that surgical treatment of unruptured intracranial aneurysms carries a low risk of morbidity and mortality and may improve the outcome in patients harboring cerebral aneurysms by preventing the devastating effects of subarachnoid hemorrhage. Aneurysm size, location, and number were risk predictors for surgical morbidity in patients with unruptured aneurysms.

Functional outcome after aneurysmal subarachnoid hemorrhage

The introduction of the operating microscope, the principle of early surgery, specialized intensive care units, the calcium antagonist nimodipine, the sophisticated pre- and postoperative management and an aggressive antiischemic pharmacological management have substantially reduced morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). In spite of this progress, many patients after rupture and surgical repair of an intracranial aneurysm exhibit substantial cognitive deficits and emotional problems although their neurological outcome was rated as good according to the Glasgow Outcome Scale (GOS = I). Therefore, a comprehensive neuropsychological examination is called for in order to evaluate the factual functional outcome after SAH. Neither focal brain damage associated with aneurysm location nor surgery but the hemorrhage itself and related events can be regarded as the most important causal factors for the late result after SAH. In contrast to the mild permanent effects of aneurysm surgery, the initial bleeding itself seems to have substantial lasting adverse neurobehavioral effects after. In concordance with other authors our own data stress the strong predictive power of the bleeding pattern such as the presence of intraventricular and/or intracerebral blood on the functional outcome after aneurysmal SAH.

A simple relationship between radiological arteriovenous malformation hemodynamics and clinical presentation: a prospective, blinded analysis of 31 cases

OBJECT

The authors sought to establish prospectively whether there is a simple relationship between radiological features of brain arteriovenous malformation (AVM) hemodynamics and a patient's clinical presentation.

METHODS

Thirty-one consecutive patients with AVMs underwent cerebral angiography at 3.8 frames/second during each standardized injection of contrast material. Contrast dilution curves were derived from the image sequences by using regions of interest (ROIs) traced on arteries feeding and veins draining the AVM nidus. Angiographic parameters were then analyzed in a blinded fashion. These parameters included the times required to reach the peak contrast density, the contrast decay time, and fractions thereof, in the ROI for each vessel. The authors determined whether these parameters, the arteriovenous transit time, and/or AVM size were related to patients' presentation with hemorrhage (11 patients), seizure (11 patients), or other clinical symptoms (nine patients). Statistically significant results were found only in analyses of arterial phase times to reach peak contrast density. Analyses of venous parameters, AVM size, and nidus transit time showed trends but no statistical significance. Arterial filling with contrast material was significantly slower in patients presenting with hemorrhage (mean 50%, 80%, and 100% of time to peak +/- standard error [SE] = 1.19+/-0.13, 1.97+/-0.18, and 3.04+/-0.34 seconds, respectively) compared with patients presenting with seizures (mean 50%, 80%, and 100% of time to peak +/- SE = 0.80+/-0.12, 1.32+/-0.18, and 1.95+/-0.29 seconds, respectively) according to analysis of variance (p<0.05) and post-hoc t-tests (p<0.05) for each parameter. Patients who presented with other symptoms had intermediate arterial filling times.

CONCLUSIONS

These simple hemodynamic parameters, which can be obtained without added risk to the patient, may help identify a subset of individuals in whom AVMs pose a higher risk of future hemorrhage and who may therefore warrant more expeditious treatment.

Embolization of incidental cerebral aneurysms by using the Guglielmi detachable coil system

OBJECT

Guglielmi detachable coil (GDC) technology is a valuable therapeutic alternative to the surgical treatment of ruptured or incidental intracranial aneurysms. The authors describe their technical and clinical experience in the use of the GDC technique in patients who underwent endovascular occlusion for the treatment of incidentally found intracranial aneurysms.

METHODS

One hundred fifteen patients with 120 incidentally found intracranial aneurysms underwent embolization by means of the GDC endovascular technique. Ninety-one patients were females and 24 were males. Patient age ranged from 13 to 80 years. In 64 patients the incidental aneurysms were discovered when unrelated nonneurological conditions signaled the need for angiography or magnetic resonance angiography (Group 1). Twenty patients who presented with incidental aneurysms that were discovered during treatment for an acutely ruptured aneurysm underwent treatment of both types of aneurysm during the acute phase of subarachnoid hemorrhage (SAH) (Group 2). Sixteen patients with incidental aneurysms were treated during the chronic phase of SAH (Group 3). Group 4 included 15 patients who had incidental aneurysms associated with brain tumors or arteriovenous malformations. Angiographic results revealed complete or near-complete occlusion in 109 aneurysms (91%) and incomplete occlusion in five aneurysms (4%). Guglielmi detachable coil embolization was attempted unsuccessfully in six aneurysms (5%). One hundred nine patients (94.8%) remained neurologically intact or unchanged from their initial clinical status. Five patients (4.3%) deteriorated as a result of immediate procedural complications. All these complications occurred in the first 50 patients treated in the series. No clinical complications were observed in the last 65 patients. In one patient, a partially embolized aneurysm ruptured 3 years postprocedure. In Groups 1 and 3, the average length of hospitalization was 3.3 days.

CONCLUSIONS

The evolution of GDC technology has proved to provide safe treatment of incidental aneurysms (a morbidity rate of 0% was achieved in the last 65 patients). The topography of the aneurysm and the clinical condition of the patient did not influence final anatomical or clinical outcomes. The GDC technology also confers a positive economic impact by decreasing hospital length of stay and by eliminating the need for postembolization intensive care.

Rebleeding during transport of patients with a ruptured intracranial aneurysm

Although many reports have described the rebleeding risk of the ruptured aneurysm in already hospitalized patients, there are only a few reports that have addressed the incidence of rebleeding in these patients before hospitalization. To improve the prognosis of patients with a ruptured intracranial aneurysm, it seems very important to know the incidence of rebleeding before hospitalization. We focused on changes in the computed tomographic (CT) scans and neurological findings at the primary hospital and our institution in 366 patients with ruptured aneurysms who were transferred on the day of the initial hemorrhage, and studied the rebleeding rates in these patients. In 73 (19.9%), we confirmed that rebleeding from the ruptured aneurysm had occurred during transport. The incidence of rebleeding in the prehospitalized patients with a ruptured aneurysm is supposed to by very high. Appropriate medical countermeasures for prevention of rebleeding in prehospitalized patients are crucial to decrease the overall mortality and morbidity rate of intracranial aneurysm.

Intracranial pressure, cerebral perfusion pressure, and SPECT in the management of patients with SAH Hunt and Hess grades I-II

The objective of our study was to examine the course of intracranial pressure (ICP) in patients with SAH Hunt and Hess grades I-II and to analyze the relationship between ICP, cerebral perfusion pressure (CPP) and cerebral blood flow (CBF). Twenty-three patients were studied. ICP, arterial blood pressure (ABP) and CPP were continuously recorded. The measurements of CBF with single-photon emission computed tomography (SPECT) were performed in fifteen patients, who showed TCD flow velocities exceeding 120 cnlJsec. In the first two days after SAH four patients (15%) showed a normal ICP, six (25%) patients had a moderate increase of ICP ranged from 15 to 25 mm Hg and thirteen (60%) patients had ICP values higher than 25 mm Hg. Seven of these patients, with ICP values higher than 40 mm Hg, showed clinical signs of delayed ischaemia. After the treatment with osmotic diuretic, ICP decreased and a clinical improvement was observed with the exception of one patient. In this patient, the SPECT study showed middle cerebral hypoperfusion concordant with the clinically ischaemic hemisphere. Our study showed the utility of the monitoring of these parameters in patients with lower grade SAH, because it allows the modulation of the therapeutic approach and defines the onset of neurological deficits secondary to cerebral ischaemia in all grades of SAH.

Therapeutic options for endovascular therapy for intracranial aneurysms

Endovascular surgical technology is in the early stages of evolution. A critical phase of this development has been microcatheter technology, which has permitted sufficiently precise intravascular navigation to safely engage the lumen of the aneurysm itself. Digital subtraction angiography, rapid filming techniques and image acquisition, and simultaneous multiplanar imaging capability are indispensable tools that are constantly being refined in the setting of ever-improving computer technology. The marriage of these different technologies has allowed effective endovascular treatment of difficult-to-access aneurysms in medically compromised patients for whom open microsurgery has inherently higher risks.

Giant aneurysms of the middle cerebral artery trifurcation treated with extracranial-intracranial arterial bypass and endovascular occlusion. Report of two cases

Giant middle cerebral artery (MCA) trifurcation aneurysms that cannot be excluded directly can be treated by flow inversion achieved by creation of an extracranial-intracranial bypass distal to the aneurysm, followed by occlusion of the parent vessel proximal to the aneurysm. As opposed to surgical occlusion, endovascular occlusion avoids dissection of the aneurysm area, and the site of occlusion can be chosen according to the flow distribution demonstrated on angiography performed during test occlusions. Two patients with giant aneurysms of the MCA trifurcation benefited from flow inversion treatment. Forty-eight hours after an MCA-superficial temporal artery bypass had been created, the M1 segment was occluded by inserting a coil in the first patient and the internal carotid artery was occluded with balloons in the second patient (there was no communicating artery in the latter case). Both occlusions were performed immediately after a clinical test of occlusion tolerance. The patients were clinically intact during the postoperative course. Follow-up angiography performed 11 and 4 months, respectively, after vessel occlusion showed that the aneurysm occlusion was stable.

Preliminary results on the management of unruptured intracranial aneurysms with magnetic resonance angiography and computed tomographic angiography

OBJECTIVE

The goal was to assess the capability of magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) to replace catheter angiography in the evaluation of unruptured intracranial aneurysms.

METHODS

A prospective evaluation of a 1-year period included all patients suspected of harboring unruptured intracranial aneurysms at a single institution. All patients underwent magnetic resonance imaging, MRA, and CTA, for comparison with intraoperative findings or results from catheter angiography. Both MRA and CTA now provide submillimeter resolution of vascular structures, with accurate detection of intracranial aneurysms of a diameter greater than or equal to 3 mm. This resolution calls into question the universal need for catheter angiography in the care of patients with suspected intracranial aneurysms. When the catheter angiography can be avoided, radiological costs can be reduced by as much as two-thirds while eliminating the risk of arterial injury and stroke.

RESULTS

Excellent visualization of the intracranial vasculature was provided by both MRA and CTA. No vascular lesion was detected at surgery or by formal angiography that was not visualized by noninvasive angiographic techniques. The three-dimensional anatomy of the aneurysm complex (unavailable with catheter angiography) was well depicted by both MRA and CTA. CTA was unique in its capacity to display the relationship of vascular structures to bone, information that is invaluable for planning operative strategies for lesions such as carotidophthalmic artery aneurysms. Additionally, acquisition of CTA images was very rapid, with a scanning time of less than 1 minute. Both MRA and CTA allowed for retrospective manipulation of data into an infinite number of views, including views that paralleled those encountered through the operative microscope. Additionally, both MRA and CTA can depict the internal anatomy of aneurysms, an ability not possessed by intra-arterial angiography. This ability alerts the surgeon to possible intraoperative risks, such as plaque in the lumen of an aneurysm or calcium within the walls of the arteries.

CONCLUSION

Both MRA and CTA provide several advantages over digital subtraction angiography, in addition to reduced costs and avoidance of arterial injury and stroke. These include retrospective manipulation of data in a 360-degree format, visualization of the internal anatomy of arteries and aneurysms, three-dimensional depiction of anatomy, and rapid data acquisition. Preliminary data and a review of the literature suggest that MRA, when used in concert with CTA, can replace catheter angiography in the assessment of select patients harboring unruptured intracranial aneurysms. Although no firm conclusions or generalizations can be drawn from this small cohort of patients, it is hoped that this report will stimulate interest and further study at other institutions.

Aneurysm size: a prognostic factor for rupture

For effective management of patients with unruptured intracranial aneurysms, prognostic criteria for rupture are needed, of which aneurysm size is a key factor. However, the critical size at which an aneurysm becomes hazardous is not known. During the last 5 years, 1558 aneurysm patients have been operated on in our centre. Of these 1248 presented with a subarachnoid haemorrhage (ruptured aneurysms) and 310 without a subarachnoid haemorrhage (unruptured aneurysms). Of the ruptured aneurysms 475 (38%) were small in size with a maximum diameter < 6 mm. Most of these small ruptured aneurysms were located on the anterior communicating artery. Of the 310 patients with unruptured aneurysms 253 (81.6%) had single aneurysms; 113 (44.7%) of those were small in size. Most of these small unruptured aneurysms were located on the middle cerebral artery. The remaining 57 patients with unruptured aneurysms harboured multiple aneurysms totalling 116 aneurysms; 50% of them were small in size. Our of 160 patients with multiple aneurysms presenting with subarachnoid haemorrhage, 34 patients had small aneurysm(s) accompanied with medium or large sized aneurysm(s); in nine (26.5%) of these 34 patients the small aneurysm was the ruptured one. These data suggest that small aneurysms < 6 mm in diameter are not innocuous and hazardous, and surgical treatment should be considered for small unruptured aneurysms even if they are less than 6 mm in diameter.

Guglielmi detachable coil embolization of acute intracranial aneurysm: perioperative anatomical and clinical outcome in 403 patients

From December 1990 to July 1995, the investigators participated in a prospective clinical study to evaluate the safety of the Guglielmi detachable coil (GDC) system for the treatment of aneurysms. This report summarizes the perioperative results from eight initial interventional neuroradiology centers in the United States. The report focuses on 403 patients who presented with acute subarachnoid hemorrhage from a ruptured intracranial aneurysm. These patients were treated within 15 days of the primary intracranial hemorrhage and were followed until they were discharged from the hospital or died. Seventy percent of the patients were female and 30% were male. The patients' mean age was 58 years old. Aneurysm size was categorized as small (60.8%), large (34.7%), and giant (4.5%); and neck size was categorized as small (53.6%), wide (36.2%), fusiform (6%), and undetermined (4.2%). Fifty-seven percent of the aneurysms were located in the posterior circulation and 43% in the anterior circulation. Eighty-two patients were classified as Hunt and Hess Grade I (20.3%), 105 Grade II (26.1%), 121 Grade III (30%), 69 Grade IV (17.1%), and 26 Grade V (6.5%). All patients in this study were excluded from surgical treatment either because of anticipated surgical difficulty (69.2%), attempted and failed surgery (12.7%), the patient's poor neurological (12.2%) or medical (4.7%) status, and/or refusal of surgery (1.2%). The GDC embolization was performed within 48 hours of primary hemorrhage in 147 patients (36.5%), within 3 to 6 days in 156 patients (38.7%), 7 to 10 days in 71 patients (17.6%), and 11 to 15 days in 29 patients (7.2%). Complete aneurysm occlusion was observed in 70.8% of small aneurysms with a small neck, 35% of large aneurysms, and 50% of giant aneurysms. A small neck remnant was observed in 21.4% of small aneurysms with a small neck, 57.1% of large aneurysms, and 50% of giant aneurysms. Technical complications included aneurysm perforation (2.7%), unintentional parent artery occlusion (3%), and untoward cerebral embolization (2.48%). There was a 8.9% immediate morbidity rate related to the GDC technique. Seven deaths were related to technical complications (1.74%) and 18 (4.47%) to the severity of the primary hemorrhage. The findings of this study demonstrate the safety of the GDC system for the treatment of ruptured intracranial aneurysms in anterior and posterior circulations. The authors believe additional randomized studies will further identify the role of this technique in the management of acutely ruptured incranial aneurysms.

Warning leak and management outcome in aneurysmal subarachnoid hemorrhage

The impact of warning leaks on management results in patients with aneurysmal subarachnoid hemorrhage (SAH) was evaluated in this prospective study. In a consecutive series of 422 patients with aneurysmal SAH, 84 patients (19.9%) had an episode suggesting a warning leak; 34 (40.5%) of these patients were seen by a physician without the condition being recognized. The warning leak occurred less than 2 weeks before a major SAH in 75% of the patients. A good outcome was experienced by 53.6% of patients who had a warning leak versus 63.3% of those who had no warning leak. In a subgroup of patients who had an interval of 3 days or less from warning leak to SAH, only 36.4% had a good outcome. The proportion of patients in good neurological condition (Hunt and Hess Grades I and II) who had a good outcome was 88.1% in the group with no warning leak versus 53.6% in the group whose SAH was preceded by a warning leak. A difference of 35% between these two groups reflects the impact of an undiagnosed warning leak on patient outcome, based on the assumption that patients with a warning leak had clinical conditions no worse than Hunt and Hess Grade II at the time of the episode. In the subgroup of patients with the short interval between warning leak and SAH, the difference was almost 52%. The difference in outcome also reflects the potential improvement in outcome that can be achieved by a correct diagnosis of the warning leak. If the correct diagnosis is made in patients seeking medical attention due to a warning leak, favorable outcomes in the overall management of aneurysmal SAH are estimated to increase by 2.8%. An active diagnostic attitude toward patients experiencing a sudden and severe headache is warranted as it offers a means of improving overall outcome in patients with SAH.

Subarachnoid hemorrhage diagnosis: lumbar puncture is still needed when the computed tomography scan is normal

OBJECTIVES

To determine the sensitivity of third-generation CT scanners for diagnosed nontraumatic subarachnoid hemorrhage (SAH) and to assess the impact of symptom duration on sensitivity.

METHODS

A retrospective chart review was performed in a university-affiliated tertiary care hospital with an annual ED volume of > 100,000 patients. The target population was all patients who presented to the ED from January 1991 to September 1994 with symptoms suggestive of SAH and who had a final diagnosis of nontraumatic SAH based on either a positive CT scan or positive spinal fluid analysis. Patients referred from outside facilities were included if they had a CT done at the study site. All CT scans were done using third-generation scanners. Official CT scan reports were used to categorize scans as positive or negative.

RESULTS

There were 140 patients identified with SAH, with a mean age of 56 years (range 10-88). The sensitivity of CT in the diagnosis of nontraumatic SAH when performed at or before 12 hours of symptom duration was 100% (80/80), and 81.7% (49/60) after 12 hours of symptom duration (95% CI 95-100% and 69.5-90.4%, respectively; p < 0.0001). Eleven of the 140 patients had a negative CT and positive spinal fluid analysis, yielding an overall sensitivity of 92.1% (129/140).

CONCLUSION

The sensitivity of third-generation CT scans for SAH decreases with time from the onset of symptoms. In this sample population, CT was able to detect all patients scanned < or = 12 hours after symptom onset. Although the study demonstrated good sensitivity of CT scan reports for SAH when the scan was performed after < or = 12 hours of symptom onset, additional real-time experience is needed to better define the potential risk of a missed SAH should this population not receive the customary lumbar puncture examination in the setting of a negative CT scan.

Temporary vessel occlusion for aneurysm surgery: risk factors for stroke in patients protected by induced hypothermia and hypertension and intravenous mannitol administration

Temporary vessel occlusion is an effective technique used by microvascular surgeons to facilitate dissection and permanent clipping of cerebral aneurysms; however, several questions remain regarding the overall safety of this technique. To identify technical and patient-specific risk factors for perioperative stroke, the authors examined a series of patients in whom induced hypertension and mild hypothermia and intravenous mannitol administration were used as protection during temporary vessel occlusion for aneurysm clipping. The study comprises a nonconcurrent prospective analysis of 132 consecutive aneurysm clippings performed with the aid of temporary vascular occlusion and a specific antiischemic anesthetic protocol at the Massachusetts General Hospital from 1991 to 1993. Factors studied included duration of the temporary clip application, number of occlusive episodes, patient age and neurological status, presence of preoperative subarachnoid hemorrhage (SAH), and intraoperative aneurysm rupture ("forced" temporary clipping), as well as whether proximal vessel occlusion or complete aneurysm trapping was used. In a univariate analysis, patient age, intraoperative aneurysm rupture, temporary clipping lasting more than 20 minutes, clipping between the 4th and 10th day after SAH, and multiple clipping episodes were all significantly associated with stroke outcome. Multivariate logistic regression revealed that intraoperative aneurysm rupture (relative risk 5.6, p = 0.02) and a duration of temporary clip application that lasted more than 20 minutes (relative risk 9.4, p = 0.04) were independently associated with stroke outcome. Overall, 5.2% of the patients had postoperative clinical strokes. Based on their findings the authors conclude that temporary clipping is a safe adjunct to aneurysm surgery, particularly when the duration of clipping is short.

Predicting outcome following surgical treatment of unruptured intracranial aneurysms: a proposed grading system

Surgical treatment of unruptured aneurysms is gaining increased support owing to the recently defined poor long-term natural history of these aneurysms. The benefit of treatment ultimately depends on the relative risk of subsequent aneurysm rupture in untreated patients versus the risk of surgery. To identify those patients at a higher risk from surgery, the authors reviewed the management of 172 patients with unruptured intracranial aneurysms treated at their institution. The size of the aneurysms ranged from 3 to 45 mm (mean 13.7 mm). Twenty-two patients (12.8%) had aneurysms in the posterior circulation, and 32 (18.6%) of these were giant aneurysms. Major morbidity occurred in 12 patients (6.9%) and five patients (2.9%) died. Multivariate logistic analysis of several risk factors revealed that aneurysm size and location had an independent correlation with surgical outcome and that patient age approached statistical significance. Patients presenting with ischemic cerebrovascular disease, in particular, did not have a higher risk of a poor outcome. A simple classification for predicting patients at high risk from surgical morbidity and mortality is proposed. Preoperative grading is based on the size and location of the aneurysm and patient's age. The lowest grade is given to young patients with small anterior circulation aneurysms, and the highest grade includes elderly patients with complex giant posterior circulation aneurysms. A retrospective analysis of this classification demonstrated a strong correlation with postoperative outcome. The incidence of poor outcome progressively increased with a higher grade, ranging from 0% in Grade 0 to 66.6% in Grade VI. An analysis of this classification on 50 consecutive surgically treated patients with unruptured aneurysms not included in the analysis also validated the predictive value of this system. Along with predicting outcome, this classification should provide a standardized format for comparison of results from different clinical centers as well as different therapeutic techniques (surgical vs. endovascular) without omission of significant risk factors found to influence outcome.