Pure surgical treatment of 109 aneurysms

AIM: Target of this study was to investigate outcomes after pure surgical treatment of intracranial aneurysms. METHODS: Patients with intracranial supratentorial circle aneurysms were retrospectively reviewed between July 1994 and October 1998. Studied cases were admitted at the Department of Neurosurgery of S. Maria-Hospital, Terni, a Government supported General Hospital. One hundred and nine Hunt and Hess Grade 0 to III patients with supratentorial circle aneurysms was studied in order to determine whether advances in the surgical management of intracranial aneurysms have improved surgical outcomes and which factors may predict outcome. All patients were managed only with standard neurosurgical aneurysms clipping procedures. Outcomes evaluation was made at patients' discharge and classified on the base of the Glasgow Outcome Scale (GOS). Surgical timing, SAH grading, pre and post surgical symptomatic vasospasm, temporary clipping, and intraoperative aneurysm rupture were correlated with outcomes. RESULTS: Surgical results showed a 75% excellent outcome. Mortality rate was 3%. Hunt and Hess grade 0 highly influenced outcome. Differences in outcomes among grades I to III were not significant. No differences in outcomes related to temporary clipping were noted. A low rate of intraoperative aneurysm rupture is reported: 5 out of 109 cases. In all these cases outcome was good, with neither mortality or morbidity. CONCLUSIONS: Results indicate a progressive improvement in surgical outcomes, suggesting that there still exist margins for improvements in pure surgical management of intracranial aneurysms.     

Effects of the Temporary Clipping in Aneurysm Surgery on the Remnant

Summary.  The residual aneurysm rate is reported between 3,8% and 21% in the cases followed after intracranial aneurysm surgery. In the formation of the residual aneurysm, the risk factors include such structural characteristics as the size and lobulation of the aneurysm, posterior circulation, para-ophtalmic localisation and intra-operative rupture.  The rates and causes of postoperative residual aneurysms were analyzed in 186 intracranial aneurysm of 160 patients, including the possible effects of temporary clipping on the residual rates. The entire series demostrated a residual rate of 7%. It was found higher in the large lobulating aneurysms and intra-operative rupture. The residual rate considerably decreased to 4,2% in the aneurysms with temporary clipping.  The determination of residual aneurysms, identification of any risk factors and elimination of recoverable factors would allow improvement of surgical results in the treatment of the intracranial aneurysms in the future. Moreover we believe that these will be useful in development of the indications for alternative treatment methods.     

Association of endovascular therapy of very small ruptured aneurysms with higher rates of procedure-related rupture

OBJECT: Procedure-related rupture during endovascular therapy of intracranial aneurysms is associated with a mortality rate of more than one third. Previously ruptured aneurysms are a known risk factor for procedure-related rupture. The objective of this study was to evaluate whether very small, ruptured aneurysms are associated with more frequent intraprocedural ruptures. METHODS: This was a retrospective cohort study in which the investigators examined consecutive ruptured aneurysms treated with coil embolization at a single institution. The study was approved by the institutional review board. Very small aneurysms were defined as < or = 3 mm. Procedure-related rupture was defined as contrast extravasation during treatment. Univariate analysis with the Fisher exact test and the Mann-Whitney U test was performed. RESULTS: Between August 1992 and January 2007, 682 aneurysms were selectively treated with coils in 668 patients. Procedure-related rupture occurred in 7 (11.7%) of 60 aneurysms < or = 3 mm, compared with 14 (2.3%) of 622 aneurysms > 3 mm (relative risk 5.2, 95% confidence interval 2.2-12.8; p < 0.001). Among cases with procedure-related rupture, inflation of a compliant balloon was associated with better outcome (Glasgow Outcome Scale Score > or = 4) compared with patients treated without balloon assistance (5 of 5 compared with 7 of 16; p = 0.05). Death resulting from procedure-related rupture occurred in 8 (38%) of 21 patients, and a vegetative state occurred in 1 patient. Clinical outcome was good in the other 12 patients (57%). CONCLUSIONS: Endovascular coil embolization of very small (< or = 3 mm) ruptured cerebral aneurysms is 5 times more likely to result in procedure-related rupture compared with larger aneurysms. Balloon inflation for hemostasis may be associated with better outcome in the event of intraprocedural rupture and merits further study.     

Intraoperative complications in aneurysm surgery: a prospective national study

OBJECT: With increasing use of endovascular procedures, the number of aneurysms treated surgically will decline. In this study the authors review complications related to the surgical treatment of aneurysms and address the issue of maintaining quality standards on a national level. METHODS: A prospective, nonselected amalgamation of every aneurysm case treated in five of six neurosurgical centers in Sweden during 1 calendar year was undertaken (422 patients; 7.4 persons/100,000 population/year). The treatment protocols at these institutions were very similar. Outcome was assessed using clinical end points. In this series, 84.1% of the patients underwent surgery, and intraoperative complications occurred in 30% of these procedures. Poor outcome from technical complications was seen in 7.9% of the surgically treated patients. Intraoperative aneurysm rupture accounted for 60% and branch sacrifice for 12% of all technical difficulties. Although these complications were significantly related to aneurysm base geometry and the competence of the surgeon, problems still occurred apparently at random and also in the best of hands (17%). The temporary mean occlusion time in the patients who suffered intraoperative aneurysm rupture was twice as long as the temporary arrest of blood flow performed to aid dissection. CONCLUSIONS: The results obtained in this series closely reflect the overall management results of this disease and support the conclusion that surgical complications causing a poor outcome can be estimated on a large population-based scale. Intraoperative aneurysm rupture was the most common and most devastating technical complication that occurred. Support was found for a more liberal use of temporary clips early during dissection, regardless of the experience of the surgeon. Temporary regional interruption of arterial blood flow should be a routine method for aneurysm surgery on an everyday basis. A random occurrence of difficult intraoperative problems was clearly shown, and this factor of unpredictability, which is present in any preoperative assessment of risk, strengthens the case for recommending neuroprotection as a routine adjunct to virtually every aneurysm operation, regardless of the surgeon's experience.     

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.     

Outcome after subarachnoid hemorrhage from a very small aneurysm: a case-control series

OBJECT: A case-control analysis of patients with SAH was performed to compare risk factors and outcomes at 6 months posthemorrhage in patients with a very small aneurysm compared with those with a larger aneurysm. METHODS: All patients with SAH who were treated between January 1998 and December 1999 were studied. A very small aneurysm was defined as "equal to or less than 5 mm in diameter." Clinical data and treatment summaries were maintained in an electronic database. The Glasgow Outcome Scale (GOS) score was determined by an independent registrar. One hundred twenty-seven patients were treated. A very small aneurysm was the cause of SAH in 42 patients (33%), whereas 85 (67%) had aneurysms larger than 5 mm (mean diameter 11 mm). There were no differences in demographic variables or medical comorbidities between the two groups. Thick SAH (Fisher Grade 3 or 4) was more common in patients with a very small aneurysm than in those with a larger aneurysm (p = 0.028). One hundred eight patients underwent microsurgery (85%), 15 underwent coil embolization (12%), and four (3%) required both procedures. Vasospasm occurred in nine patients (21%) with very small aneurysms compared with 14 (16%) with larger aneurysms (p = 0.62). Shunt-dependent hydrocephalus occurred in nine patients (21%) with very small aneurysms and in 19 (22%) with larger aneurysms (p = 1). The mean GOS score for both groups was 4 (moderately disabled) at 6 months. CONCLUSIONS: Small aneurysms produce thick SAH more often than larger aneurysms. There is no difference in outcome after SAH between patients with a very small aneurysm and those with a larger aneurysm.     

Selective intraoperative angiography in intracranial aneurysm surgery: intraoperative factors associated with aneurysmal remnants and vessel occlusions

BACKGROUND: The objective of this study was to assess the role of selective intraoperative angiography and to analyze the factors associated with faulty clip application. METHODS: Two hundred thirty-eight patients undergoing surgery for intracranial aneurysms were studied consecutively for intraoperative angiography (IOA)-related events. The procedure was performed in 155 operations. Demographic details, clinical grade of the patient, location and size of the aneurysm, intraoperative rupture, application of the temporary clip, IOA findings, and final outcome were analyzed. RESULTS: In the 155 patients in the series, there were 125 anterior circulation aneurysms and 30 on the vertebrobasilar system. Aneurysms were smaller than 10 mm in 63% of the patients, and 19 were giant aneurysms. Thirty-eight percent were unruptured, 36% were Hunt and Hess Grades I and II, 21% were Grade III, and 5% were Grades IV and V. An intraoperative rupture occurred in 18 operations. Intraoperative angiography was normal in 88%; in 11 cases (7%) there was a residual neck, and in 8 (5%), occlusion of the artery was observed. An incomplete clipping was significantly related to intraoperative rupture of the aneurysm (p < 0.008) and anterior location of the aneurysm (p = 0.05), whereas vessel occlusion had a significant association with posterior location of the aneurysm (p < 0.0005). An eventful IOA had significant association with poor outcome (p < 0.003). CONCLUSION: Intraoperative rupture and a posterior location of the aneurysm had a significant correlation with residual aneurysm and vessel occlusion, respectively. The use of IOA is justified in aneurysms associated with these factors.     

Anterior paraclinoid aneurysms

OBJECT: The characteristics of a previously unclassified paraclinoid aneurysm arising from the anterolateral (dorsal) wall of the proximal internal carotid artery were retrospectively analyzed in seven patients (five women and two men) who were treated surgically for an aneurysm in this unusual location. METHODS: One patient presented with subarachnoid hemorrhage (SAH) caused by rupture of this aneurysm. The lesions were found incidentally (five cases) or during investigation of SAH due to another aneurysm (one case). There was a female predominance in this series; all female patients harbored multiple aneurysms. All patients underwent surgery. Removal of the anterior clinoid process was necessary because the proximal neck of the aneurysm was closely adjacent to the dural ring. CONCLUSIONS: This special group of aneurysms is very rare, is located exclusively in the intradural space, and carries the risk of SAH. The results of surgical treatment for this aneurysm are quite satisfactory.     

Relation among aneurysm size, amount of subarachnoid blood, and clinical outcome

OBJECT: The authors of recent reports have suggested that smaller aneurysms are associated with more extensive subarachnoid hemorrhage (SAH), which could potentially presage poor outcome in patients harboring these lesions. The authors reviewed their clinical experience to determine if this theory has a basis in truth. METHODS: The authors undertook a retrospective review of a consecutive series of patients with aneurysmal SAH. Computed tomography scans and angiograms were studied to establish SAH scores and aneurysm size. RESULTS: One hundred thirty-three patients were treated during a 2-year period (January 2003-December 2004). There were 101 female and 32 male patients whose mean age was 56.7 years. The location distribution of aneurysms that bled was as follows: anterior communicating artery (56 cases), posterior communicating artery (34 cases), middle cerebral artery (21 cases), posterior circulation (16 cases), and paraclinoid region (six cases). The mean aneurysm size was 6.2 mm (range 2-26 mm). The mean SAH score was 18.3 (not normally distributed, p < 0.01, D'Agostino-Pearson test). One hundred three patients underwent surgical exploration and placement of an aneurysm clip, 21 underwent deployment of a coil, and two underwent both therapies; seven patients died prior to intervention. No correlation was found between aneurysm size and SAH score (r(s) = -0.023, p = 0.8) or between small aneurysm size and poor Glasgow Outcome Scale score (p = 0.13). In fact, the trend was the opposite. The SAH score did, however, correspond strongly with the admission Hunt and Hess grade (p < 0.0001), indicating the strong correlation between grade and volume of intracranial blood. Outcome was best explained in the multivariate analysis by the following factors: admission Hunt and Hess grade, age, and clinical vasospasm (p < 0.0001) with the proportion of cases correctly classified as 79.7%. CONCLUSIONS: Evaluation of the results in the present clinical series suggests that there is no relation between aneurysm size and volume of subarachnoid blood. The volume of cisternal blood correlates with Hunt and Hess grade but is not an independent determinant of outcome. Outcome is related to the following triad of well-established clinical factors: Hunt and Hess grade, age, and clinical vasospasm.     

Epidemiological features and diagnostic evaluation of intracranial aneurysms

Female gender and cigarette smoking appear to be risk factors for the development of multiple intracranial aneurysms. An acquired nature is likely in this form. The mechanism of aneurysm formation in patients with sickle cell anemia is apparently different. These patients also present multiple aneurysms that show propensity for vertebrobasilar territory and appear at a younger age. Familial cerebral aneurysms are diagnosed once heritable connective tissue disorders have been excluded. The age of patients tends to be lower and the size of aneurysm to be smaller at the time of rupture in the familial form. These aneurysms are less frequently found in the anterior communicating artery than the sporadic aneurysms. A high incidence of asymptomatic familial aneurysms was detected in people with family histories of intracranial aneurysms studied by means of magnetic resonance angiography. Furthermore, familial aneurysms are more likely to rupture in families having members with aneurysmal subarachnoid hemorrhage (SAH) than in those without. The results of an interesting study using color "power" transcranial Doppler ultrasound in patients with aneurysmal SAH suggest that as the intracranial pressure diminished, the size of the aneurysm increased, and there was relatively little change between maximum and minimum dimensions during the cardiac cycle, i.e., the pulsatility is reduced. The use of postoperative angiography after clipping is a matter of debate. The indication more widely accepted is in large aneurysms with a wide neck, in which incomplete clipping can be suspected. Taking into account the current low risk of angiography in centers of excellence, its routine use may be recommended. Aneurysm remnants, vessel occlusion, vasospasm, and newly identified aneurysms are the main findings that were reported.     

Small unruptured aneurysm verification (SUAVe Study, Japan)--interim report

A prospective study (SUAVe Study, Japan) is in progress at 13 national hospitals to determine the surgical indications for small unruptured intracranial aneurysm. These hospitals are observing the natural history of small unruptured aneurysms (under 5 mm diameter) without surgical treatment. Since October 2000, 455 aneurysms (393 patients) with 75 aneurysms excluded by film judgment committees have been registered, of which 380 aneurysms (329 cases) have been followed up for a mean of 13.8 months (5 aneurysms for 36 months, 68 for 24 months, 164 for 12 months, and 64 for 6 months). Four aneurysms have already ruptured (3 multiple and 1 single). The annual rupture rate was 0.8% (95% confidence interval 0.2-3%). Another 18 aneurysms have enlarged including seven aneurysms treated for enlargement over 2 mm in size. Considering this finding, the annual rupture rate might rise slightly. The important factors for rupture and enlargement were multiplicity of aneurysm, female, patient aged over 70 years old, and location of aneurysm (anterior communicating artery, basilar artery). The growth rate may be faster in multiple aneurysms than in single aneurysms.     

Follow-up of intracranial aneurysms in autosomal-dominant polycystic kidney disease

BACKGROUND: Approximately 8% of autosomal-dominant polycystic kidney disease (ADPKD) patients have intracranial aneurysms. The risk of growth and rupture of those discovered by presymptomatic screening is key to the feasibility and success of a screening program. This study was initiated to ascertain this risk. METHODS: ADPKD patients were offered screening with magnetic resonance (MR) imaging that included three-dimensional time-of-flight MR angiographic and three-dimensional phase-contrast sequences. Patients with aneurysms were recommended periodic surveillance, initially at 6 months and yearly, and less frequently after demonstration of their stability. RESULTS: Twenty-two saccular and one fusiform aneurysms were detected at the initial screening in 21 patients from 19 families (seven men and 14 women, 47.9 +/- 10.6 years old). All the saccular aneurysms were small (mean diameter 3.5 mm, range 2.0 to 6.5 mm) and the majority (77%) in the anterior circulation. Two patients died from unrelated causes without further follow-up. One patient was lost to follow-up. A new 2 mm middle cerebral artery aneurysm developed in one patient. One aneurysm increased from a size of 4 mm to 5 mm after a follow-up of 105 months. No aneurysmal development or growth occurred in the remaining 16 patients. No aneurysmal rupture occurred during a mean imaging follow-up of 81 months and a mean clinical follow-up of 92 months. During the period of the study, two additional ADPKD patients, with three intracranial aneurysms detected elsewhere by presymptomatic MR angiographic screening, were referred for surgical treatment. The larger size of these aneurysms (10, 8, and 8 mm) probably reflects referral bias. CONCLUSION: Most intracranial aneurysms detected by presymptomatic screening in ADPKD patients are small and in the anterior circulation. The follow-up results do not suggest an increased risk for growth and rupture, compared to those of intracranial aneurysms in the general population. These data do not support widespread screening for intracranial aneurysms in the ADPKD population.     

"De novo" aneurysms. A clinical review

The authors present seven cases drawn from 620 consecutive cases over 30 years, in which previously undemonstrated (hence "de novo") intracranial aneurysms formed and ruptured at intervals of 3-20 years, after clipping of an initial aneurysm. Six patients were treated for rupture of a second aneurysm. All six had undergone successful treatment of a previous aneurysm; pre- and postoperative angiography showed not only successful clipping of the first aneurysm but also no incidence of multiple aneurysms. In no case was a major artery occluded at the time of the initial surgery. The implications as to natural history and the advisability of repeated arteriography in some patients with aneurysms are discussed.     

Combined surgical and endovascular techniques of flow alteration to treat fusiform and complex wide-necked intracranial aneurysms that are unsuitable for clipping or coil embolization.

OBJECT: Certain intracranial aneurysms, because of their fusiform or complex wide-necked structure, giant size, or involvement with critical perforating or branch vessels. are unamenable to direct surgical clipping or endovascular coil treatment. Management of such lesions requires alternative or novel treatment strategies. Proximal and distal occlusion (trapping) is the most effective strategy. In lesions that cannot be trapped, alteration in blood flow to the "inflow zone," the site most vulnerable to aneurysm growth and rupture, is used. METHODS: From 1991 to 1999 the combined neurosurgical-neuroendovascular team at the Massachusetts General Hospital (MGH) managed 48 intracranial aneurysms that could not be clipped or occluded. Intracavernous internal carotid artery aneurysms were excluded from this analysis. By applying a previously described aneurysm rupture risk classification system (MGH Grades 0-5) based on the age of the patient, aneurysm size, Hunt and Hess grade, Fisher grade, and whether the aneurysm was a giant lesion located in the posterior circulation, the authors found that a significant number of patients were at moderate risk (MGH Grade 2; 31.3% of patients) and at high risk (MGH Grades 3 or 4; 22.9%) for treatment-related morbidity. The lesions were treated using a variety of strategies--surgical, endovascular, or a combination of modalities. Aneurysms that could not be trapped or occluded were treated using a paradigm of flow alteration, with flow redirected from either native collateral networks or from a surgically performed vascular bypass. Overall clinical outcomes were determined using the Glasgow Outcome Scale (GOS). A GOS score of 5 or 4 was achieved in 77.1%, a GOS score of 3 or 2 in 8.3%, and death (GOS 1) occurred in 14.6% of the patients. Procedure-related complications occurred in 27.1% of cases; the major morbidity rate was 6.3% and the mortality rate was 10.4%. Three patients experienced aneurysmal hemorrhage posttreatment; in two patients this event proved to be fatal. Aneurysms with MGH Grades 0, 1, 2, 3, and 4 were associated with favorable outcomes (GOS scores of 5 or 4) in 100%, 92.8%, 71.4%, 50%, and 0% of instances, respectively. CONCLUSIONS: Despite a high incidence of transient complications, intracranial aneurysms that cannot be clipped or occluded require alternative surgical and endovascular treatment strategies. In those aneurysms that cannot safely be trapped or occluded, one approach is the treatment strategy of flow alteration.     

Complications of endovascular treatment of cerebral aneurysms

BACKGROUND: The International Subarachnoid Aneurysm Trial has indicated that endovascular management of acutely ruptured aneurysms may be superior to surgery. Clearly poor results ensue from both forms of treatment, and some of these are because of technical complications (not just poor patient status). This observational study was performed to determine the complications associated with the endovascular treatment of ruptured and unruptured cerebral aneurysms. METHODS: Prospective data were gathered on 118 patients undergoing 126 endovascular treatment sessions for 126 nontraumatic cerebral aneurysms (30% unruptured) over a 3-year period. The average age was 51 years (range, 12-85 years). Females comprised 75% of the population treated. RESULTS: Good outcomes were achieved with 71% of the procedures (59% for subarachnoid hemorrhage [SAH]; 97% for unruptured). No bleeding or rebleeding occurred from treated aneurysms. Vessel or aneurysm perforation occurred in 11 cases and led to adverse outcome in 3 (3%). Thromboembolic complications were felt to cause cerebral infarction in 8 cases (6%). The risk of vessel/aneurysm rupture or thromboembolic stroke was greater in patients with SAH. Eight attempts to coil (6%) were initially unsuccessful. Two of these were later successfully coiled and others had surgery. None of the failed attempts led to clinical deterioration. Balloon-assisted coiling (BAC) was not associated with an increased complication rate. CONCLUSIONS: Vessel perforation and thromboembolic stroke are significant risks of endovascular treatment, especially after SAH. In our hands, however, BAC does not add to this risk.     

Screening of risk groups for discovering intracranial aneurysms before rupture

In development of intracranial aneurysms contribute genetic factors together with smoking, hypertension, diabetes mellitus. Epidemiology studies suggest that as many as 5% of people harbour a cerebral aneurysm by age 75. Rupture of cerebral aneurysm is the most frequent cause of spontaneous subarachnoid haemorrhage (up to 80%.) Annual incidence of SAH is 10-14/100 000, but only 15-20% of aneurysms will rupture, and that will happen probably between 40-60 years. The morbidity and mortality of aneurismal subarachnoid (SAH) continues to be high. It is not possible to predict who has aneurysm and is it going to bleed or not, but it is possible to reveal high risk groups (polycystic kidney disease, Ehlers-Danlos sy, Marphan sy, family history of cerebral aneurysms, suspect de novo aneurysm formation in patients with prior history of cerebral aneurysm). Reviewing data from literature and reporting cases from each group with high risk, that have been screened and aneurysms discovered, authors wish to focus interest on this matter and propose screening program for these groups of patients. The mortality and morbidity in cases treated before rupture is significantly lower than after SAH, so screening programs could save many lives. According to our preliminara data, mostly based on control angiographies after 8-10 zears in patients previouslz operated for intracranial aneurysmas, from 15 angipgraphies 4 revealed new aneurysms (26% in 10 years period) with total number of 6 de novo formed aneurysms, which is not valid due to small number of patients but strongly suggests the importancy of screening program for risk groups.     

Ruptured de novo intracranial aneurysms

Summary Objective. We describe the actual state of ruptured de novo intracranial aneurysms to contribute to a guideline of follow-up for the patients with treated intracranial aneurysm.Methods. The authors retrospectively investigated 12 cases drawn from 483 consecutive cases of aneurysmal subarachnoid hemorrhage at our institute over a period of 22 years, in which a previously undemonstrated (hence de novo) intracranial saccular aneurysm formed and ruptured after successful treatment of a prior aneurysm.Findings. The 12 cases constitute 2.5% of the 483 patients who left our hospital alive. Eleven cases were females and one was a male with a mean age of 55.7 years (range 29–75) at the first subarachnoid haemorrhage (SAH) and an interval between the first and the second rupture of 10.7 years (range: 2.6–23.8, standard deviation: 6.86, 95% confidence interval: 6.39–15.1). Four cases did not have risk factors such as hypertension, family history, smoking, multiple aneurysms, and moyamoya disease. None of these ruptured de novo aneurysms was at the same location as the original lesion. One-third (4 cases) of the de novo lesions in our series were found on the opposite side to each prior lesion.Interpretation. For not only young but also elder patients with a treated aneurysm (from the fifth decade to the sixth), especially for women, late angiography or alternative modalities of less-invasive examination should be considered. To detect de novo intracranial aneurysms before rupture, the search for a de novo aneurysm should be performed within 6.39 years after a previous examination that shows an aneurysm to be nonexistent, in view of the 95% confidence interval of the mean time to de novo aneurysmal rupture (6.39–15.1 years). If applied this survey, 75% (8 cases of 12 cases) of our de novo aneurysms would be detected before rupture.     

Internal carotid artery bifurcation aneurysms: surgical experience

Internal carotid artery (ICA) bifurcation aneurysms are relatively uncommon and frequently rupture at a younger age compared to other intracranial aneurysms. We have treated a total of 999 patients for intracranial aneurysms, of whom 89 (8.9%) had ICA bifurcation aneurysms, and 42 of the 89 patients were 30 years of age or younger. The present study analyzed the clinical records of 70 patients with ICA bifurcation aneurysms treated from mid 1997 to mid 2003. Multiple aneurysms were present in 15 patients. Digital subtraction angiography films were studied in 55 patients to identify vasospasm and aneurysm projection. The aneurysm projected superiorly in most of these patients (37/55, 67.3%). We preferred to minimize frontal lobe retraction, so widely opened the sylvian fissure to approach the ICA bifurcation and aneurysm neck. Elective temporary clipping was employed before the final dissection and permanent clip application. Vasospasm was present in 24 (43.6%) of 55 patients. Forty-eight (68.6%) of the 70 patients had good outcome, 14 (20%) had poor outcome, and eight (11.4%) died. Patients with ICA bifurcation aneurysms tend to bleed at a much younger age compared to those with other intracranial aneurysms. Wide opening of the sylvian fissure and elective temporary clipping of the ICA reduces the risk of intraoperative rupture and perforator injury. Mortality was mainly due to poor clinical grade and intraoperative premature aneurysm rupture.     

Endovascular coil occlusion of 1811 intracranial aneurysms: early angiographic and clinical results

OBJECTIVE: We sought to evaluate the early angiographic and clinical outcomes of the first session of endovascular coil occlusion of a large number of patients with intracranial aneurysms treated by five neurointerventionalists during a decade at a single center. METHODS: We performed retrospective analyses of pre- and postprocedural angiographic studies and early clinical outcomes. Enrolled patients underwent endovascular treatment of intracranial aneurysms with detachable coils. RESULTS: A total of 1811 aneurysms in 1579 patients were treated with coil occlusion. Of these, 90 to 100% occlusion of 86.5% of the aneurysms was achieved. In 82.3% of the procedures, no complications occurred. The clinical outcome profile at primary discharge according to the Glasgow Outcome Scale was as follows: Grade V, 74.6%; Grade IV, 6.7%; Grade III, 11.1%; Grade II, 3.1%; and Grade I, 4.5%. In patients with large aneurysms with wide necks, a lower occlusion rate and an increased complication rate were encountered. The use of three-dimensional and fibered coils resulted in higher occlusion rates. Balloon remodeling and stent deployment increased the complication rate. Previous aneurysm rupture, procedural complications, and vasospasm correlated with poor outcome. Of the patients in poor grade after aneurysm rupture, 42% recovered to Glasgow Outcome Scale Grade IV or V, as opposed to 90% of patients who were treated for unruptured aneurysms. The ischemic complication rate was 9%, and the hemorrhagic complication rate was 3%. The early procedural morbidity rate was 5.3%, and the procedural mortality rate was 1.5%. The management mortality rate was 4.4%. CONCLUSION: These data confirm the safety and efficacy of endovascular coil occlusion for patients with intracranial aneurysms.     

Prospective risk of hemorrhage in patients with vertebrobasilar nonsaccular intracranial aneurysm

OBJECT: Nonsaccular intracranial aneurysms (NIAs) are characterized by dilation, elongation, and tortuosity of intracranial arteries. Dilemmas in management exist due to the limited regarding the natural history of this disease entity. The objective of this study was to determine the prospective risk of subarachnoid hemorrhage (SAH) in patients with vertebrobasilar NIAs. METHODS: All patients with vertebrobasilar fusiform or dolichoectatic aneurysms that had been radiographically demonstrated between 1989 and 2001 were identified. These patients' medical records were retrospectively reviewed. A prospective follow-up survey was sent and death certificates were requested. Based on results of neuroimaging studies, the maximal diameter of the involved artery, presence of SAH, and measurements of arterial tortuosity were recorded. Nonsaccular intracranial aneurysms were classified according to their radiographic appearance: fusiform, dolichoectatic, and transitional. Dissecting aneurysms were excluded. The aneurysm rupture rate was calculated based on person-years of follow up. Predictive factors for rupture were evaluated using univariate analysis (p < 0.05). One hundred fifty-nine patients, 74% of whom were men, were identified. The mean age at diagnosis was 64 years (range 20-87 years). Five patients (3%) initially presented with hemorrhage; four of these patients died during follow up. The mean duration of follow up was 4.4 years (692 person-years). Nine patients (6%) experienced hemorrhage after presentation; six hemorrhages were definitely related to the NIA. The prospective annual rupture rate was 0.9% (six patients/692 person-years) overall and 2.3% in those with transitional or fusiform aneurysm subtypes. Evidence of aneurysm enlargement or transitional type of NIA was a significant predictor of lesion rupture. Six patients died within 1 week of experiencing lesion rupture. CONCLUSIONS: Risk of hemorrhage in patients harboring vertebrobasilar NIAs is more common in those with evidence of aneurysm enlargement or a transitional type of aneurysm and carries a significant risk of death.