Familial intracranial aneurysms

The authors report seven individuals from two families, all of whom had aneurysmal subarachnoid hemorrhage. These cases and all reported cases of familial aneurysms (243 aneurysms in 177 patients from 74 families) were submitted to computer-aided multivariate analysis to determine if the aneurysms or the patients who harbor them differ from sporadic aneurysm cases. Familial aneurysms rupture at a smaller size (mean diameter 10.5 mm), and when the patient is younger (mean age 42.3 years and decennial age at peak incidence 40 to 49 years). There is a similar sex distribution (male to female ratio 48:52), a similar incidence of multiple aneurysms (21.5%), and a similar predominance of females over males with multiple aneurysms (2.2:1). Anterior communicating artery aneurysms occur less often in familial cases (19%) than in sporadic cases. In sibling pairs the aneurysms occur at the same or at mirror sites, and rupture within the same decade twice as frequently as randomly selected nonfamilial aneurysm patient pairs. The occurrence of aneurysms at identical and mirror sites is more frequent in familial cases and appears to be a function of the degree of kinship between affected individuals. These observations suggest a genetic basis for the pathogenesis of familial intracranial aneurysms.     

False localization of rupture site in patients with multiple cerebral aneurysms and subarachnoid hemorrhage

OBJECTIVE: Patients with subarachnoid hemorrhage and multiple intracranial aneurysms present a unique challenge to the neurosurgeon. Unless all aneurysms can be clipped through a single craniotomy, the surgeon must accurately determine which aneurysm has ruptured. Misjudgment may result in disastrous postoperative rebleeding from the untreated but true ruptured lesion. We assessed the risk of false localization of the rupture site and subsequent rebleeding and documented the problems in predicting the true rupture site when patients have multiple intracranial aneurysms. METHOD: We reviewed the records of a consecutive series of 93 patients treated over a period of 12 years who presented with their first subarachnoid hemorrhage and who had multiple intracranial aneurysms. The rupture site was determined on the basis of computed tomographic and angiographic findings, and the supposed ruptured aneurysm was clipped within 2 days of hemorrhage in each patient. Additional aneurysms that could not be accessed in the same surgical session were operated on at a later stage. All patients' records were reviewed, and all computed tomographic scans and angiograms, including repeat studies performed in some patients, were retrospectively reevaluated by the authors, who had no knowledge of the patients' clinical information. RESULTS: The location of the aneurysm that ruptured was verified at the time of surgery or during the autopsy in 76 patients (82%). The aneurysm that ruptured was the one predicted as ruptured by the surgeon before surgery in 69 patients (91%) and in retrospect in 72 patients (95%). Five of the 6 patients in whom the ruptured aneurysm was not correctly identified were thought to have only a single aneurysm. Four patients rebled after surgery, and 2 patients died as a result of the rebleeding. CONCLUSION: In the reported series, the most common cause of rebleeding soon after aneurysm surgery was failure to obliterate the ruptured aneurysm, usually because it was missed on the initial angiogram. The results support not only meticulous radiological investigation of all intracranial arteries before surgery but also thorough surgical inspection of the target aneurysm in all cases of subarachnoid hemorrhage even after one candidate lesion has been discovered.     

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

OBJECT: The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed. METHODS: One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using lifetable analyses and Cox's proportional hazards regression models including time-dependent covariates. The median follow-up time was 19.7 years (range 0.8-38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1-1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93-1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04-2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21-7.66, p = 0.02). CONCLUSIONS: Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.     

Endothelial Nitric Oxide Synthase Gene [G894T] polymorphism as a possible risk factor in aneurysmal subarachnoid haemorrhage

Summary Background. The exact aetiology, growth and rupture of intracranial aneurysms is unclear. In this study we investigated a possible association between intracranial aneurysm rupture and polymorphism of the endothelial nitric oxide synthase gene G894T. Methods. Endothelial nitric oxide synthase gene polymorphism of 53 patients with ruptured intracranial aneurysms and 60 control subjects were analysed by the polymerase chain reaction-restriction fragment length polymorphism technique. The genotype distribution and allele frequencies of endothelial nitric oxide synthase gene polymorphism in patients with ruptured intracranial aneurysm and healthy subjects were compared. Findings. The homozygous (TT) genotype frequency was significantly higher in patients with ruptured intracranial aneurysms. It was also found that the presence of eNOS 894TT genotype was significantly associated with the risk of intracranial aneurysm rupture (p < 0.05). Conclusion. Polymorphism in exon 7 of the endothelial nitric oxide synthase gene G894T seems to be a possible risk factor for intracranial aneurysm rupture. Correspondence: ünal ?züm, MD, PhD, Department of Neurosurgery. Cumhuriyet University School of Medicine, 58140 Sivas, Turkey.     

The influence of surgical experience on the rate of intraoperative aneurysm rupture and its impact on aneurysm treatment outcome

BACKGROUND: The influence of surgical experience on the result of aneurysm surgery remains unclear. To determine the impact of surgical experience we considered the occurrence of intraoperative aneurysm rupture (IAR) during microneurosurgery for intracranial aneurysms as an objective factor that could be evaluated. METHODS: A retrospective study was performed on 379 consecutive patients with 490 cerebral aneurysms operated upon from 1989 to 1995. RESULTS: IAR occurred in 6.7% of aneurysms and 8.7% of patients. There was a direct inverse relationship between the annual caseload of the surgeon and the risk of IAR. New neurological deficits (NND) occurred in 21% of patients with IAR, which accounts for 1.8% of NND in all patients with aneurysms. CONCLUSION: Although there seems to be a direct relationship between surgical experience and the risk of IAR, the impact on the overall treatment outcome of cerebral aneurysms is rather limited.     

Rupture of intracranial aneurysms during treatment with Guglielmi detachable coils: incidence, outcome, and risk factors

OBJECT: The aim of this study was to assess the incidence and outcome of procedure-related rupture of intracranial aneurysms in patients treated with Guglielmi detachable coils (GDCs) and to identify risk factors for this complication. METHODS: Procedure-related rupture occurred in seven of 264 treated aneurysms in 239 consecutive patients. Aneurysm size, history of previous subarachnoid hemorrhage (SAH) caused by the treated aneurysm, timing of treatment after SAH, and the use of a temporary occlusion balloon in the seven procedures in which rupture occurred were compared with the remaining 257 procedures, and these findings were correlated with data from 13 studies in the literature, in which results of 2030 aneurysm treatments were reported. CONCLUSIONS: Procedure-related rupture of intracranial aneurysms during GDC treatment occurs in 2.5% of cases and is responsible for 1% of treatment-related deaths. Risk factors are as follows: small aneurysm size, previous SAH, and probably the use of a temporary occlusion balloon.     

Factors associated with aneurysm size in patients with subarachnoid hemorrhage: effect of smoking and aneurysm location

OBJECTIVE: Intracranial aneurysm size is an important determinant of risk of rupture and outcome after rupture. Risk factors influencing aneurysm formation and growth are not well defined. In this study, we examined the association between known risk factors for cerebrovascular disease and size of intracranial aneurysms in patients with aneurysmal subarachnoid hemorrhage. METHODS: We analyzed prospectively collected data from the placebo-treated group in a multicenter clinical trial conducted at 54 neurosurgical centers in North America. The presence, location, and size of intracranial aneurysms were determined by review of the admission angiograms. Pertinent information regarding the presence of various cerebrovascular risk factors was collected for each patient. Using logistic regression analysis, we identified independent determinants of aneurysm size from demographic, clinical, and angiographic characteristics of the participants. The impact of aneurysm size on 3-month mortality was analyzed after adjusting for potential confounding factors. RESULTS: For 298 patients admitted with subarachnoid hemorrhage, the ruptured aneurysms were graded as small (<13 mm) in 235 patients (79%) and large (> or =13 mm) in 63 patients (21%). In the logistic regression model, both smoking at any time (odds ratio, 2.2; 95% confidence interval, 1.1-4.5) and middle cerebral artery origin (odds ratio, 2.5; 95% confidence interval, 1.3-4.9) were independently associated with large aneurysms. Neither hypertension, diabetes mellitus, nor alcohol and illicit drug use were associated with large-sized aneurysms. After adjusting for initial Glasgow Coma Scale score and age in the logistic regression model, the presence of large-sized aneurysms was independently associated with 3-month mortality (odds ratio, 2.3; 95% confidence interval, 1.1-4.8). CONCLUSION: Cigarette smoking and middle cerebral artery origin seem to increase the risk for developing large aneurysms in patients predisposed to intracranial aneurysm formation. Further studies are required to investigate the mechanism underlying the association between cigarette smoking and intracranial aneurysm formation.     

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

OBJECT: The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed. METHODS: One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using life-table analyses and Cox's proportional hazards regression models including time-dependent covariates. The median follow-up time was 19.7 years (range 0.8-38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1-1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93-1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04-2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21-7.66, p = 0.02). CONCLUSIONS: Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.     

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.     

Size of cerebral aneurysms and related factors in patients with subarachnoid hemorrhage

BACKGROUND: As the indication for surgical treatment of incidentally discovered small aneurysms remains controversial. METHODS: We retrospectively investigated the characteristics of small ruptured aneurysms and examined the relationship between the size and location of ruptured intracranial aneurysms and the sex, age, lifestyle, and medical history of 280 patients with ruptured aneurysm treated at our institute. RESULTS: The mean diameter of ruptured aneurysms in this series was 7.6 mm. In diameter, 135 (48.2%) ranged between 5 and 10 mm; 73 (26.1%) were smaller than 5 mm. The size of the ruptured aneurysms was significantly smaller (mean 6.5 mm) in patients with non- or poorly controlled hypertension than in normotensive patients (mean 8.3 mm) (p < 0.05). Ruptured aneurysms in the anterior communicating artery (AcomA) and anterior cerebral artery (ACA) were significantly smaller (p < 0.01) than those in the internal carotid artery or middle cerebral artery. Among 58 patients with multiple aneurysms, only 7 (12%) suffered rupture of aneurysms smaller than 5 mm (p < 0.01). Patients younger than 40 years and patients with a family history of subarachnoid hemorrhage appeared to predispose to the rupture of small-sized aneurysms, although those did not affect the statistical significance. CONCLUSIONS: This study shows that even aneurysms smaller than 10 mm may rupture. However, treatment decisions for unruptured aneurysm should not be based solely on the size of the unruptured aneurysms. Our data implies that even small aneurysms in the AcomA and ACA had an increased tendency for rupture, and that hypertensive patients were at higher risk for the rupture of small 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.     

Multiple intracranial aneurysms: determining the site of rupture

A retrospective hospital chart and radiograph review was performed of all patients with multiple intracranial aneurysms seen over a 52-month period. Sixty-nine patients with a total of 205 aneurysms were studied. Among the patients with aneurysms, the incidence of multiple aneurysms was 33.5%. Multiple aneurysms were much more common in women, with a female to male ratio of 5:1 for all patients and 11:1 for patients with three or more aneurysms. Common locations for multiple aneurysms were the posterior communicating artery (22%), middle cerebral artery (21.5%), anterior communicating artery (12%), and ophthalmic artery (11%). However, locations with the highest probability of rupture were the anterior communicating artery (62%), posterior inferior cerebellar artery (50%), and basilar artery summit (50%). The middle cerebral artery was the least likely site for rupture. In contrast to previous studies, in this series irregularity of contour was more important than size in identifying the site of rupture. Using a simple algorithm outlined in the text, it was possible to identify the site of aneurysm rupture in 97.5% of cases.     

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.     

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.     

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.     

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.     

Changes in wall shear stress magnitude after aneurysm rupture

Computational fluid dynamics (CFD) studies on cerebral aneurysms have attempted to identify surrogate hemodynamic parameters to predict rupture risk. We present a case of bilateral mirror image aneurysms, one of which ruptured soon after imaging. Wall shear stress values of the ruptured aneurysm changed by 20–30 % after rupture because of change in the aneurysm shape. Findings from our case suggest that CFD studies comparing unruptured and ruptured aneurysms may not yield valid estimation on aneurysm rupture risk because of changes in aneurysm shape after rupture. Changes in aneurysm shape after rupture should be considered in CFD research.     

Temporary occlusion in surgical management of intracranial aneurysm. Report of 54 cases]

Temporary arterial occlusion (TAO) is commonly used in the surgery of intracranial giant aneurysms. Its usefulness and safety in the surgical management of all cases of aneurysms remains to be proved. We report a series of 54 patients operated on for an intracranial aneurysm with the use of TAO. Among the 27 patients, admitted before the 4th day following post subarachnoid hemorrhage with I or II on WFNS score clinically, 24 had early aneurysm surgery. The size of the aneurysm was small in 16 cases, medium in 22, large in 13 and giant in 3 cases. The protocol proposed by Batjer in 1988 for large and giant aneurysms (etomidate, normotention and hypervolemia) was used without any electrophysiological monitoring. All patients underwent a post-operative cerebral CT scan to evaluate the incidence of a cerebral ischemia. Serial transcranial doppler was used to evaluate the severity of vasospasm. Clinical results were assessed using the GOS. TAO was elective in 51 patients and done after peroperative aneurysm rupture in 3 patients. The duration of TAO was less than 5 mn in 25 patients, between 5 and 10 min in 12, between 10 and 15 in 11, between 15 and 20 in 5 and more than 20 min in one patient. The last one developed a reversible neurological deficit secondary to ischemia attribuated to TAO. Intracranial aneurysm peroperative rupture was noted in 3 patients, clinical vasospam in 13 patients. These results allow us to recommend the routine use of TAO in the surgery of intracranial aneurysm. When application time is limited and cerebral protection used, TAO is safe. It decreases the risk of intraoperative rupture from a 18% rate in literature to 4.2% in our present experience and the risk of symptomatic vasospasm is not increased.     

Natural history of unruptured cerebral aneurysms of the unoperated and observed cases

PURPOSE: Natural history of unruptured cerebral aneurysms is still a matter of discussion. In this study, we investigated the prognosis of unruptured cerebral aneurysms of unoperated cases in a prospective design. METHODS: Between September, 1992 and December, 2001, we have encountered a 256 cases of unruptured cerebral aneurysms. Among them, 118 cases were observed and were checked every year for their status. The endpoint was designed as their death and aneurysm rupture. Their rupture rate, mortality due to aneurysm death, and the cause of death other than aneurysm were investigated. Univariate analysis, chi-square test was used as statistics. A p-value less than 0.05 was considered as significant. RESULTS: Annual rupture rate of unoperated unruptured cerebral aneurysms of size below 5 mm, between 5-15 mm, and over 15 mm increased according to the aneurysm size, 0.4%, 3.3% and 9.9% respectively. The sole risk factor for the feasibility of rupture of unruptured aneurysms was their size (p < 0.001). Aneurysm related mortality, however, was high in posterior circulation aneurysms. In patients under 70 years of age, 45% of patients died of cerebral aneurysms, but this rate decreased to 17% for patients over 70 years of age. CONCLUSION: The rupture rate of unruptured cerebral aneurysms over 5 mm in size is not low. Unruptured aneurysms of the posterior circulation may have a much higher risk of rupture, so further investigation is necessary.     

A clinical feature and therapeutic strategy in pituitary adenomas associated with intracranial aneurysms

We studied the clinical feature and treatment strategy of pituitary adenomas associated with intracranial aneurysms. Among 102 pituitary adenoma patients (mean age: 54.8 years old) who received MR angiography and/or 3D-CT angiography, seven patients (6.9%) had intracranial aneurysms. The association of an aneurysm was more common in large size adenomas (p<0.05). According to the location of the aneurysms, five patients had these in the paraclinoid portion or cavernous portion of the internal carotid artery. Using MR images, we classified the aneurysms associated with pituitary adenomas as non-adjacent, adjacent, and intra-adenoma types. In non-adjacent types, an aneurysm is located apart from the adenoma, and has less chance of exposure during transsphenoidal surgery. In adjacent types, an aneurysm is located adjacent to the adenoma, and could be exposed during transsphenoidal surgery. In intra-adenoma types, an aneurysm is encased in the adenoma. In non-adjacent type aneurysms, a resection of the pituitary adenoma can be carried out before aneurysm treatment due to the low risk of rupture during surgery. In adjacent types, a tumor resection can precede aneurysm treatment in cases of low rupture risk aneurysms and untreatable aneurysms. In intra-adenoma types, adenoma resection should come after treatment of the aneurysms. Neurosurgeons should be careful about not only the presence of aneurysms in preoperative images during transsphenoidal surgery planning, but also their locations and proximity to adenomas. Such information may be crucial in deciding the order of treatment.