Microsurgical treatment of unruptured intracranial aneurysms. A consecutive surgical experience consisting of 450 aneurysms treated in the endovascular era

The risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms: anatomical consideration and infarction territory

PURPOSE

An anterior communicating artery is a common location for both ruptured and unruptured intracranial aneurysms, and microsurgery is sometimes necessary for their successful treatment. However, postoperative infarction should be considered during clipping due to the complex surrounding structures of anterior communicating artery aneurysms. This study aimed to evaluate the risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms and its clinical outcomes.

METHODS

The data of patients who underwent microsurgical clipping of an unruptured anterior communicating artery aneurysm in our hospital between January 2008 and December 2020 were retrospectively analyzed. The patients' demographic data, anatomical features of the anterior communicating artery complex and aneurysm, surgical technique, characteristics of postoperative infarction, and its clinical course were evaluated.

RESULTS

Notably, among 848 patients, 66 (7.8%) and 34 (4%) patients had radiologic and symptomatic infarctions, respectively. Univariate and multivariate logistic regression analyses showed that hypertension (odds ratio (OR), 1.99; [Formula: see text]), previous stroke (OR, 3.89; [Formula: see text]), posterior projection (OR, 5.58; [Formula: see text]), aneurysm size (OR, 1.17; optimal cut-off value, 6.14 mm; [Formula: see text]), and skull base-to-aneurysm distance (OR, 1.15; optimal cut-off value, 11.09 mm; [Formula: see text]) were associated with postoperative infarction. In the pterional approach, a closed A2 plane was an additional risk factor (OR, 1.88; [Formula: see text]). Infarction of the subcallosal and hypothalamic branches was significantly associated with symptomatic infarction ([Formula: see text]).

CONCLUSION

Hypertension, previous stroke, posteriorly projecting aneurysms, aneurysm size, and highly positioned aneurysms are independent risk factors for postoperative infarction during surgical clipping of an unruptured anterior communicating artery aneurysm. Additionally, a closed A2 plane is an additional risk factor of postoperative infarction in patients undergoing clipping via the pterional approach.

Procedural complications in patients undergoing microsurgical treatment of unruptured intracranial aneurysms: a single-center experience with 1923 aneurysms

BACKGROUND

With the growing use of endovascular therapy (EVT) to manage unruptured intracranial aneurysms (IAs), detailed information regarding periprocedural complication rates of microsurgical clipping and EVT becomes increasingly important in determining the optimal treatment for individual cases. We report the complication rates associated with open microsurgery in a large series of unruptured IAs and highlight the importance of maintaining surgical skill in the EVT era.

METHODS

We reviewed all cases of unruptured IAs treated with open microsurgery by a single neurosurgeon between July 1997 and June 2019. We analyzed surgical complications, deaths, and patient-reported outcomes.

RESULTS

A total of 1923 unruptured IAs in 1750 patients (mean age 44 [range: 6-84], 62.0% [1085/1750] female) were treated surgically during the study period. Of the aneurysms treated, 84.9% (1632/1923) were small, 11.1% (213/1923) were large, and 4.1% (78/1923) were giant. Aneurysm locations included the middle cerebral artery (44.2% [850/1923]), internal carotid artery (29.1% [560/1923]), anterior cerebral artery (21.0% [404/1923]), and vertebrobasilar system (5.7% [109/1923]). The overall mortality rate was 0.3% (5/1750). Surgical complications occurred in 7.4% (129/1750) of patients, but only 0.4% (7/1750) experienced permanent disability. The majority of patients were able to return to their preoperative lifestyles with no modifications (95.9% [1678/1750]).

CONCLUSIONS

At a high-volume, multidisciplinary center, open microsurgery in carefully selected patients with unruptured IAs yields favorable clinical outcomes with low complication rates. The improvement of EVT techniques and the ability to refer cases for EVT when a high complication rate with open microsurgery was expected have contributed to an overall decrease in surgical complication rates. These results may serve as a useful point of reference for physicians involved in treatment decision-making for patients with unruptured IAs.

Microsurgical and endovascular treatment of un-ruptured cerebral aneurysms by European hybrid neurosurgeons to balance surgical skills and medical staff management

Background

In Europe, aneurysm treatment performed by dually trained neurosurgeons is extremely scarce. We provide outcome data for un-ruptured aneurysm patients treated at a European hybrid center to prove that hybrid neurosurgeons achieve clinical and angiographical results allowing to integrate hybrid neurosurgery into routine aneurysm treatment. This will not only help to maintain neurovascular microsurgical skills but will influence staff costs in related hospitals.

Methods

We retrospectively analyzed all consecutively treated un-ruptured aneurysm patients between 2000 and 2016. The decision-making took into account the pros and cons of both modalities and considered patient and aneurysm characteristics. Clinical outcome was assessed by the modified Rankin scale (mRS). Occlusion rates were stratified into grade I for 100%, grade II for 99–90%, and grade III for <90% occlusion. To account for the introduction of stents, two treatment periods (p1, 2000 to 2008; p2, 2009 to 2016) were defined.

Results

The study population consisted of 274 patients (median age 55 years) harboring 338 un-ruptured aneurysms. Microsurgery (MS) was performed in 51.8% and endovascular therapy (EVT) in 43.1%; 5.1% required combined treatment. Overall, 93% showed a favorable clinical outcome (mRS 0–2), 94.3% after MS and 91.5% after EVT. Grade I aneurysm occlusion was achieved in 82.6% patients, 91.9% after MS and 72.9% after EVT. Procedure-related complications occurred after MS in 5.6% and after EVT in 4.4% patients. Mortality was recorded for five (1.8%) patients, one patient after MS and four after EVT. For the EVT cohort, significant improvement from p1 to p2 was seen with clinical outcomes (P=0.030, RR = 0.905, CI: 0.8351–0.9802) and occlusion rates (P=0.039, RR = 0.6790, CI: 0.499–0.923).

Conclusion

Hybrid neurosurgeons achieve qualified clinical and angiographic results. Dual training will allow to maintain neurovascular caseloads and preserve future aneurysm treatment within neurosurgery. Furthermore economic benefits could be observed in hospital management.

Intraoperative Aneurysm Rupture: Surgical Experience and the Rate of Intraoperative Rupture in a Series of 1000 Aneurysms Operated on by a Single Neurosurgeon

OBJECTIVE

This study aims to examine the risk factors that can cause intraoperative rupture (IOR), and especially, the role of surgical experience. To our knowledge, this is the first study to analyze the effect of the surgeon's experience on the IOR rate in 2 different perspectives.

METHODS

A total of 1000 aneurysms in 775 patients were operated on by a single neurosurgeon. The clinical and radiologic data and intraoperative video recordings of all patients were retrospectively analyzed. To evaluate the role of the surgeon's experience on the IOR rate, the aneurysms were divided chronologically into both 5-year periods and each 100 aneurysms. Number, stage, severity, location, management of IORs, and patients' outcomes were determined.

RESULTS

IOR occurred in 55 aneurysms (5.5% per aneurysm). The incidence of IOR decreased gradually in the first 2 groups of 5-year periods (11.4% and 5.9%, respectively). However, in the last 3 groups, the decline remained stable (4%-5%). Considering all groups, this decrease was statistically significant (P = 0.037). When this evaluation was made for each group of 100 aneurysms, similar results were obtained. Mortality also gradually decreased over the years (P = 0.035). Of 8 possible risk factors, rupture status was found to be the only independent predictor for IOR (OR, 8.68; 95% confidence interval, 3.69-20.47; P <0.001).

CONCLUSIONS

Increased surgical experience reduces the IOR rate from 10%-11% to 4%-5% after an average of 250 aneurysm operations. However, this rate does not decrease further with more experience. To our knowledge, a learning curve regarding IOR is presented for the first time in the literature.

Clinical features of ischemic complications after unruptured middle cerebral artery aneurysm clipping: patients and radiologically related factors

Postoperative ischemic complication results in neurological sequelae and longer hospitalization after unruptured middle cerebral artery (MCA) aneurysm clipping surgery. We evaluated the radiological and patient-related factors associated with ischemic complications after unruptured MCA aneurysm clipping surgery. Patient demographics, radiological findings, and intraoperative factors were compared between patients with and without postoperative ischemic complications. The clinical courses and outcomes of postoperative ischemic complications were compared according to the types of ischemic complication. Forty-two out of 2227 patients (1.9%) developed postoperative ischemic complications after MCA aneurysm clipping. Multivariate analysis revealed that diabetes mellitus (DM) was a patient-related factor. Intraarterial (IA) calcification of the distal internal carotid artery (ICA), preoperative M1 stenosis, and M1 aneurysm were radiological factors that increased the risk of postoperative ischemic complications. DM was significantly associated with divisional branch territory infarction (P = 0.04). The time to first presentation of ischemic complication was significantly longer in divisional branch territory infarction than perforator territory infarction (67.8 ± 75.9 h vs. 22 ± 20.7, P = 0.023). Twelve out of 42 patients with ischemic complications (28.6%) had unfavorable outcome (mRS > 3). Perforator territory infarction was significantly associated with an unfavorable outcome (mRS > 3, P = 0.019). IA calcification of the distal ICA, M1 stenosis and aneurysms, and DM were significantly associated with postoperative ischemic complications after unruptured MCA aneurysm clipping. Patients with DM should be closely monitored postoperatively to detect delayed occurrence of divisional branch infarction. Trial registration number: 2019-1002, Date of registration: January 1, 2005, "retrospectively registered".

Can Young Vascular Neurosurgeons Become Proficient in Microsurgical Clip Reconstruction in the Endovascular Era? A Rotterdam Cohort Spanning 2 Decades with Propensity Score Matching for Complexity

BACKGROUND

Little is known about the results of young vascular neurosurgeons who perform only microsurgical clip reconstruction in the era since the International Subarachnoid Aneurysm Trial (ISAT) or about the training and caseload required to equivocate the results of senior, more experienced colleagues. The aim of this study was to compare clinical outcomes of patients treated by young and senior vascular neurosurgeons at Erasmus MC University Medical Center Rotterdam, adjusting for case mix.

METHODS

A partially prospective and partially retrospective database was used. Hierarchical mixed models with a random intercept for surgeon were used for confounder adjustment, and propensity score matching for complexity was used to create comparable groups.

RESULTS

The study included 609 patients harboring 767 aneurysms. Most (86%) of the aneurysms had at least 1 complexity characteristic, with the majority having 3 characteristics. The most often encountered complexity characteristics were the presence of a broad neck and the presence of branches emerging from the aneurysm. Use of temporary clipping and skull base approaches was significantly higher in the young vascular neurosurgeons group (P < 0.0001). The complexity score differed significantly between senior and young vascular neurosurgeons (P < 0.001). After propensity score matching for complexity, multivariable logistic regression showed young vascular neurosurgeons to be significantly associated with better outcomes for ruptured aneurysms (propensity score weighted odds ratio 0.55 [95% confidence interval 0.35-0.88], P = 0.01).

CONCLUSIONS

In a high-volume neurovascular center where both endovascular and microsurgical treatment options are available, young vascular neurosurgeons can be trained to achieve at least the same results as their senior colleagues despite increased complexity.

Microsurgical Treatment of Unruptured Anterior Communicating Artery Aneurysms: Approaches and Outcomes in a Large Contemporary Series and Review of the Literature

BACKGROUND

With advances in endovascular techniques, the relative roles of microsurgery and endovascular therapy in the management of intracranial aneurysms have become less clear, and data regarding treatment-specific outcomes are increasingly important.

OBJECTIVE

To describe our experience with microsurgery in a large series of unruptured anterior communicating artery aneurysms (ACOMMAAs) and detail our treatment decision-making process based on individual aneurysm morphology.

METHODS

We retrospectively reviewed unruptured ACOMMAAs treated microsurgically at our center between 1997 and 2018, recording aneurysm size, surgical approach, occlusion rates, neurological outcomes, and complications.

RESULTS

We treated 300 unruptured ACOMMAAs in 300 patients, mean age 49 yr, 180 (60.0%) female, including 245 (81.7%) small, 50 (16.7%) large, and 5 (1.7%) giant aneurysms. Most underwent a pterional approach (253, 84.3%), with orbitozygomatic or anterior interhemispheric approaches in 35 (11.7%) and 12 (4%), respectively. Greater than 95% occlusion was achieved in 284 (94.7%), 90% to 95% occlusion in 13 (4.3%), and 3 (1.0%) underwent wrapping. Serious complications occurred in 3 patients (1.0%) resulting in 2 deaths (0.7%), and minor complications in 12 (4.0%). At final follow-up, good neurological outcome was observed in 297 (99.0%) patients.

CONCLUSION

Given clinical equipoise regarding optimal treatment of unruptured ACOMMAAs, this work provides a benchmark for achievable microsurgical outcomes. Future surgical/endovascular studies should separate results of ruptured and unruptured lesions and describe aneurysm morphology to allow for better comparison of outcomes between treatments. We suggest that open microsurgery represents an important option for select, morphologically complex ACOMMAAs, and that a multidisciplinary approach offers optimal patient outcomes.

Clinical and morphological profile of aneurysms of the anterior communicating artery treated at a neurosurgical service in Southern Brazil

Background:

The aim of the study was to characterize the clinical profile of patients with anterior communicating artery (ACoA) aneurysms and examine potential correlations between clinical findings, aneurysm morphology, and outcome.

Methods:

A review of medical records and diagnostic neuroimaging reports of patients treated at a neurosurgical service in Porto Alegre, Brazil, between August 2008 and January 2015 was performed.

Results:

During the period, 100 patients underwent surgery for ACoA aneurysms. Fifteen had unruptured aneurysms and 85 had ruptured aneurysms. Ruptured aneurysms had a higher aspect ratio than unruptured ones (2.37 ± 0.71 vs. 1.93 ± 0.51, P = 0.02). Intraoperative rupture occurred in 3%, and temporary clipping was performed in 15%. Clinical vasospasm occurred in 43 patients with ruptured aneurysms (50.6%). Overall, mortality was 26%; 25 patients in the ruptured group (29.4%) and one in the unruptured group (6%). The Glasgow Outcome Scale (GOS) was favorable (GOS 4 or 5) in 54% of patients, significantly more so in those with unruptured aneurysms (P = 0.01). In patients with ruptured aneurysms, mortality was associated with preoperative Hunt and Hess (HH) score (P < 0.001), hydrocephalus (P < 0.001), and clinical complications (P < 0.001). Unfavorable outcomes were associated with HH score (P < 0.001), Fisher grade (P = 0.015), clinical vasospasm (P = 0.012), external ventricular drain (P = 0.015), hydrocephalus (P < 0.001), and presence of clinical complications (P = 0.001). In patients with unruptured aneurysms, presence of clinical complications was the only factor associated with mortality (P < 0.001).

Conclusion:

Despite advances in the management of subarachnoid hemorrhage and surgical treatment of aneurysms, mortality is still high, especially due to clinical complications.

[Principles of surgical treatment for patients with asymptomatic aneurysms and cerebral aneurysms in the cold period after spontaneous intracranial hemorrhages]

Surgical treatment of patients with cerebral aneurysms still remains one of the most important issues of cerebrovascular neurosurgery, which is associated with both complexity of treatment and risks posed by the disease. The purpose of this publication is to discuss the recommendations and algorithms adopted at the Neurosurgical Institute for choosing surgical treatment of patients with single and multiple intracranial aneurysms based on the clinical course of disease and anatomical morphological classifications of aneurysms. The study was based on a large clinical material: we analyzed treatment outcomes in 1,621 patients (2009-2017); of these, 966 (59.5%) patients were operated on using microsurgical techniques, and 655 (40.4%) patients underwent endovascular surgery. Surgical treatment of patients with cerebral aneurysms has been performed in close cooperation between two vascular (microsurgical and endovasal) departments, using the latest technical innovations.

Microsurgical treatment of unruptured middle cerebral artery aneurysms: a large, contemporary experience

OBJECTIVE

Advances in endovascular therapy for the treatment of middle cerebral artery (MCA) aneurysms have led to scrutiny of its benefits compared with microsurgical repair. To provide information regarding complication rates and outcomes, the authors reviewed the results of a large series of unruptured MCA aneurysms treated with open microsurgery.

METHODS

The authors included all patients who underwent surgical repair of an unruptured MCA aneurysm between 1997 and 2015. All surgical procedures, including clipping, wrapping, bypass, and parent artery occlusion, were performed by a single neurosurgeon. Aneurysm occlusion was assessed using intraoperative digital subtraction angiography (DSA) or DSA and indocyanine green videoangiography in all cases. Postoperatively, all patients were monitored in a neurointensive care unit overnight. Clinical follow-up was scheduled for 2-4 weeks after surgery, and angiographic follow-up was performed in those patients with subtotally occluded aneurysms at 1, 2, and 5 years postoperation.

RESULTS

The authors treated 750 unruptured MCA aneurysms in 716 patients: 649 (86.5%) aneurysms were small, 75 (10.0%) were large, and 26 (3.5%) were giant. Most aneurysms (n = 677, 90%) were treated by primary clip reconstruction. The surgical morbidity rate was 2.8%, and the mortality rate was 0%. Complete angiographic aneurysm occlusion was achieved in 92.0% of aneurysms. At final follow-up, 713 patients had a modified Rankin Scale (mRS) score of 0, 2 patients had an mRS score of 2 or 3, and 1 had an mRS score of 4.

CONCLUSIONS

In high-volume centers, microsurgical management of MCA aneurysms can be performed with very low morbidity rates. Currently, microsurgical repair appears to be a highly effective method of treating MCA aneurysms.

Coiling Versus Microsurgical Clipping in the Treatment of Unruptured Middle Cerebral Artery Aneurysms: A Meta-Analysis

BACKGROUND

Open microsurgical clipping of unruptured intracranial aneurysms has long been the gold standard, yet advancements in endovascular coiling techniques have begun to challenge the status quo.

OBJECTIVE

To compare endovascular coiling with microsurgical clipping among adults with unruptured middle cerebral artery aneurysms (MCAA) by conducting a meta-analysis.

METHODS

A systematic search was conducted from January 2011 to October 2015 to update a previous meta-analysis. All studies that reported unruptured MCAA in adults treated by microsurgical clipping or endovascular coiling were included and cumulatively analyzed.

RESULTS

Thirty-seven studies including 3352 patients were included. Using the random-effects model, pooled analysis of 11 studies of microsurgical clipping (626 aneurysms) revealed complete aneurysmal obliteration in 94.2% of cases (95% confidence interval [CI] 87.6%-97.4%). The analysis of 18 studies of endovascular coiling (759 aneurysms) revealed complete obliteration in 53.2% of cases (95% CI: 45.0%-61.1%). Among clipping studies, 22 assessed neurological outcomes (2404 aneurysms), with favorable outcomes in 97.9% (95% CI: 96.8%-98.6%). Among coiling studies, 22 examined neurological outcomes (826 aneurysms), with favorable outcomes in 95.1% (95% CI: 93.1%-96.5%). Results using the fixed-effect models were not materially different.

CONCLUSION

This updated meta-analysis demonstrates that surgical clipping for unruptured MCAA remains highly safe and efficacious. Endovascular treatment for unruptured MCAAs continues to improve in efficacy and safety; yet, it results in lower rates of occlusion.

Hemodynamics Associated With Intracerebral Arteriovenous Malformations: The Effects of Treatment Modalities

The understanding of the physiology of cerebral arteriovenous malformations (AVMs) continues to expand. Knowledge of the hemodynamics of blood flow associated with AVMs is also progressing as imaging and treatment modalities advance. The authors present a comprehensive literature review that reveals the physical hemodynamics of AVMs, and the effect that various treatment modalities have on AVM hemodynamics and the surrounding cortex and vasculature. The authors discuss feeding arteries, flow through the nidus, venous outflow, and the relative effects of radiosurgical monotherapy, endovascular embolization alone, and combined microsurgical treatments. The hemodynamics associated with intracranial AVMs is complex and likely changes over time with changes in the physical morphology and angioarchitecture of the lesions. Hemodynamic change may be even more of a factor as it pertains to the vast array of single and multimodal treatment options available. An understanding of AVM hemodynamics associated with differing treatment modalities can affect treatment strategies and should be considered for optimal clinical outcomes.

Effect of age on outcomes and practice patterns for patients with anterior communicating artery aneurysms

BACKGROUND

With widespread utilization of noninvasive imaging, small unruptured anterior communicating artery (AcoA) aneurysms are increasingly detected in the general population, particularly in elderly patients. We investigated the association between age and clinical characteristics and outcomes of patients with unruptured AcoA aneurysms.

METHODS

Between January 2008 and May 2016, information on 179 consecutive patients with unruptured AcoA aneurysms was obtained and included demographic data, aneurysm features, risk factors for formation and rupture, treatment type, complications, and follow-up information. A 2-tailed t test was used for continuous data and the chi-square test for categorical variables. Statistical significance was set at P value < 0.05.

RESULTS

There were 76 patients 65 and older (42.5%) and 103 younger than 65 (57.5%). Conservative management was more common in older patients (67.1% vs. 41.7%, P=0.001). Endovascular treatment was more commonly used in the older population (80% vs. 61% of the treated aneurysms in older and younger group, P=0.16). Treatment-related complications were 8% but resulted in permanent neurological deficits in one patient (1.2%). Among conservatively treated aneurysms, three (3.2%) ruptured at follow-up resulting in patient death in two cases (2.4%). All three ruptures occurred in elderly patients.

CONCLUSIONS

With a modern approach that emphasizes endovascular therapy, especially in older individuals, unruptured AcoA aneurysms can be treated with a very low morbidity. Among patients with small aneurysms for which treatment was not deemed indicated or necessary, the rate of rupture at follow-up was not negligible, with 5.8% of older patients experiencing bleeding from the aneurysm.

Quantitative analysis of the effect of institutional case volume on complications after surgical clipping of unruptured aneurysms

OBJECTIVE The mechanism by which greater institutional case volume translates into improved outcomes after surgical clipping of unruptured intracranial aneurysms (UIAs) is not well established. The authors thus aimed to assess the effect of case volume on the rate of various types of complications after clipping of UIAs. METHODS Using information on the outcomes of inpatient admissions for surgical clipping of UIAs collected within a national database, the relationship of institutional case volume to the incidence of different types of complications after clipping was investigated. Complications were subdivided into different categories, which included all complications, ischemic stroke, intracerebral hemorrhage, medical complications, infectious complications, complications related to anesthesia, and wound complications. The relationship of case volume to different types of complications was assessed using linear regression analysis. The relationships between case volume and overall complication and stroke rates were fit with both linear and quadratic equations. The numerical cutoff for institutional case volume above and below which the authors found the greatest differences in mean overall complication and stroke rate was determined using classification and regression tree (CART) analysis. RESULTS Between October 2012 and September 2015, 125 health care institutions reported patient outcomes from a total of 6040 cases of clipping of UIAs. On linear regression analysis, increasing case volume was negatively correlated to both overall complications (r² = 0.046, p = 0.0234) and stroke (r² = 0.029, p = 0.0557) rate, although the relationship of case volume to the complication (r² = 0.092) and stroke (r² = 0.067) rate was better fit with a quadratic equation. On CART analysis, the cutoff for the case number that yielded the greatest difference in overall complications and stroke rate between higher- or lower-volume centers was 6 cases/year and 3 cases/year, respectively. CONCLUSIONS Although the authors confirm that increasing case volume is associated with reduced complications after clipping of UIAs, their results suggest that the relationship between case volume and complications is not necessarily linear. Moreover, these results indicate that the effect of case volume on outcome is most evident between very-low-volume centers relative to centers with a medium-to-high volume.

Aneurysmal Neck Clipping as the Primary Treatment Option for Both Ruptured and Unruptured Middle Cerebral Artery Aneurysms

Objective

Although middle cerebral artery (MCA) aneurysms are less amenable to coil embolization, an increasing number of studies support favorable endovascular treatment for them. The purpose of this study is to compare the outcomes of two different treatments (surgery versus coiling) and evaluate the benefits of surgical clipping for MCA aneurysms.

Methods

Here we retrospectively analyzed the outcomes of 178 ruptured and unruptured MCA aneurysms treated in patients between September 2008 and April 2012. Parameters assessing treatment outcomes include degree of aneurysm occlusion, presence of regrowth, clinical status, and complications.

Results

Among 178 MCA aneurysms, 153 were treated surgically. After a mean follow-up of 12 months, the surgery group showed a clinically significant complete occlusion rate (98%) compared with the coiling group (56%) (p<0.001). Follow-up radiologic evaluation showed a higher regrowth rate (four of 16 cases) in the coiling group than in the surgery group (one of 49 cases) (p=0.003). There was no statistically significant difference in favorable clinical outcome rate between the two groups. The procedure-related permanent morbidity and mortality rates were 2% (three of 153 cases) in the surgery group and 0% (0 of 25 cases) in the coiling group.

Conclusion

Compared to endovascular treatment, surgical neck clipping for both ruptured and unruptured MCA aneurysms results in a significantly higher complete obliteration rate and less regrowth. Therefore, even in this endovascular era, we still recommend surgical clipping as the primary treatment option for MCA aneurysms rather than coil embolization.

Factors for Achieving Safe and Complete Treatment for Unruptured Saccular Aneurysm Smaller Than 10 mm by Simple Clipping or Simple Coil Embolization

OBJECTIVE

Reducing complications from unruptured aneurysms (UAs) treatment is important. We clarify the criteria for achieving safe and complete treatment for UAs ≤10 mm by clipping or coil embolization.

METHODS

This study included 59 newly treated UAs in the past 2 years. We prospectively decided on criteria to recommend active treatment. UAs ≤10 mm and in ≤75 year-olds, located at in the internal carotid artery at the paraclinoid portion and the posterior circulation aneurysms except for a vertebral artery-inferior posterior cerebellar artery aneurysm were mainly treated by coil embolization, and those in the internal carotid artery except at the paraclinoid portion, in the anterior or middle cerebral artery, and in the vertebral artery-inferior posterior cerebellar artery were treated preferably by clipping. UAs with a height/neck ratio or a dome/neck ratio ≤1.4 were treated preferentially by clipping. Specific preoperative imaging and careful manipulation were adopted for clipping.

RESULTS

Fifty-seven (96.6%) achieved modified Rankin scale (mRS) 0-1, 2 (3.4%) mRS 2-5, and 0 had mRS 6. Fifty-three UAs (89.8%) achieved complete occlusion (CO) and 7 (10.1%) had neck remnants (NR). Forty-one UAs (100%) within the criteria achieved mRS 0-1, 40 (98%) achieved CO, and 1 (2%) NR. The odds ratio of NR for those outside the criteria was 18.5 (95% confidence interval, 1.83-186.6) (P < 0.05). CO treated within the criteria was 39 and NR was 1. CO treated outside the criteria was 14 and NR was 5 (P < 0.05). The mRS 0-1 with age ≤75 years was 55 and the mRS 2-6 was 0. The mRS 0-1 with age ≥76 years was 2 and the mRS 2-6 was 2 (P < 0.01).

CONCLUSIONS

The treatment for UAs within the criteria, with the most recent points of concern, can lead to safe and complete results.

Outcome After Clipping of Unruptured Intracranial Aneurysms Depends on Caseload

OBJECTIVE

Although most neurovascular centers currently have a coil first policy, the percentage of coiled versus clipped aneurysms, as well as treatment outcomes, varies strongly between these centers. This study evaluates the impact of an increase in clipping caseload on treatment outcome in a large single-center series.

METHODS

All consecutive patients who underwent microsurgical clipping of unruptured intracranial aneurysms between January 2003 and April 2014 in our department were analyzed retrospectively. According to the change of the chairman in the neurosurgical department (1 September 2008) with a subsequent increase in the clipping volume, the entire cohort was divided into 2 groups with equal time intervals (historic and current cohorts).

RESULTS

There were 94 clipped unruptured intracranial aneurysms in the historic cohort and 252 in the current cohort. Unfavorable outcome at 6 months postoperatively (defined as modified Rankin Score >2) was observed in 8 cases (8.5%) in the historic cohort and 7 cases (2.8%) in the current cohort (P < 0.0001). The surgical mortality decreased from 3.2% to 0%. Cerebral infarction on postoperative computed tomography scan was observed in 25 cases (26.6%) in the historic cohort and 19 cases (7.5%) in the current cohort (P < 0.0001). Within the current cohort, there was a progressive improvement of surgical outcome over the time.

CONCLUSIONS

The improvement of the surgical outcome after increasing the clipping caseload underlines the importance of sufficient surgical volume for maintenance of competitive treatment results.

Clinical Risk Factors Affecting Procedure-Related Major Neurological Complications in Unruptured Intracranial Aneurysms

PURPOSE

The operative risk and natural history rupture risk for the treatment of unruptured intracranial aneurysms (UIAs) should be evaluated. The purpose of this study was to report our experience with treating UIAs and to outline clinical risk factors associated with procedure-related major neurological complications.

MATERIALS AND METHODS

We treated 1158 UIAs in 998 patients over the last 14 years. All patients underwent operation performed by a single microvascular surgeon and two interventionists at a single institution. Patient factors, aneurysm factors, and clinical outcomes were analyzed in relation to procedure-related complications.

RESULTS

The total complication rate was 22 (2.2%) out of 998 patients. Among them, complications developed in 14 (2.3%) out of 612 patients who underwent microsurgery and in 8 (2.1%) out of 386 patients who underwent endovascular procedures. One patient died due to intraoperative rupture during an endovascular procedure. The procedure-related complication was highly correlated with age (p=0.004), hypertension (p=0.002), and history of ischemic stroke (p<0.001) in univariate analysis. The multivariate analysis revealed previous history of ischemic stroke (p=0.001) to be strongly correlated with procedure-related complications.

CONCLUSION

A history of ischemic stroke was strongly correlated with procedure-related major neurological complications when treating UIAs. Accordingly, patients with UIAs who have a previous history of ischemic stroke might be at risk of procedure-related major neurological complications.

Comparison of the Efficacy and Safety of Endovascular Coiling Versus Microsurgical Clipping for Unruptured Middle Cerebral Artery Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVE

Middle cerebral artery aneurysms (MCAAs) are regularly treated by both microsurgical clipping and endovascular coiling. We performed a systematic meta-analysis to compare the safety and efficacy of these 2 methods.

METHODS

Literature was reviewed for all studies reporting angiographic occlusion and/or functional outcomes in adults with unruptured MCAA treated by endovascular coiling or microsurgical clipping. All studies in English that reported results for adults (≥18 years) with unruptured MCAAs, from 1990 to 2011 were considered for inclusion.

RESULTS

Twenty-six studies involving 2295 aneurysms treated with clipping or coiling for unruptured MCAAs were included for analysis. There were 1530 aneurysms that were treated with clipping and 765 aneurysms treated with coiling. Pooled analysis revealed failure of aneurysmal occlusion in 3.0% (95% confidence interval [CI] 1.2%-7.4%) of clipped cases. Pooled analysis of 15 studies (606 aneurysms) involving coiling and occlusion revealed lack of occlusion rates of 47.7% (95% CI 43.6%-51.8%) with the fixed-effects model and 48.2% (95% CI 39.0%-57.4%) with the random-effects model. Thirteen studies examined neurological outcomes after clipping and were pooled for analysis. Both fixed-effect and random-effect models revealed unfavorable outcomes in 2.1% (95% CI 1.3%-3.3%) of patients. There were 17 studies evaluating potential unfavorable neurological outcomes after coiling that were pooled for analysis. Fixed-effect and random-effect models revealed unfavorable outcomes in 6.5% (95% CI 4.5%-9.3%) and 4.9% (95% CI 3.0%-8.1%) of patients, respectively.

CONCLUSIONS

Based on this systematic review and meta-analysis of unruptured MCAAs, after careful consideration of patient, aneurysmal, and treatment center factors, we recommend surgical clipping for unruptured MCAA.

The natural history and treatment options for unruptured intracranial aneurysms

Recent advances in angiographic technique have raised our awareness of the presence of unruptured intracranial aneurysms (UIAs). However, the appropriate management for these lesions remains controversial. To optimize patient outcomes, the physician must weigh aneurysmal rupture risk associated with observation against the complication risks associated with intervention. In the case that treatment is chosen, the two available options are surgical clipping and endovascular coiling. Our paper summarizes the current body of literature in regards to the natural history of UIAs, the evolution of the lesion if it progresses uninterrupted, as well as the safety and efficacy of both treatment options. The risks and benefits of treatment and conservative management need to be evaluated on an individual basis and are greatly effected by both patient-specific and aneurysm-specific factors, which are presented in this paper. Ultimately, this body of data has led to multiple sets of treatment guidelines, which we have summated and presented in this paper.

Surgical treatment of unruptured intracranial aneurysms in a low-volume hospital--outcome and review of literature

BACKGROUND

The aim of this study was to evaluate surgical outcome of unruptured intracranial aneurysms (UIAs) in a low-volume hospital and compare the results with the recent literature.

METHODS

A retrospective review of all consecutive craniotomies for UIA from July 1999 through June 2009 was performed. Morbidity was defined as modified Rankin Scale (mRS) ≥ 3 and evaluated six weeks after surgery. Cognitive function was evaluated at rehabilitation-to-home discharge. A PubMed database search (2001-2011) seeking retrospective, single-center studies reporting on surgical outcome of UIAs was performed.

RESULTS

There were 47 procedures performed in 42 patients to treat 50 UIAs (mean of 5 annual craniotomies). The mean age was 54.7 ± 12.1 years and mean aneurysm size was 7.6 ± 4.0mm. Favorable outcome (mRS 0-2) at six weeks after surgery was achieved in 45 of 47 procedures (95.7%). Aneurysm size ≥ 12 mm was statistically significant related to adverse outcome defined as mRS change ≥ 1 (71% vs. 29%; p = 0.018). Five patients (10.6%) with favorable neurological outcome (mRS 2) presented with cognitive impairment at rehabilitation-to-home discharge. There was no significant difference in overall morbidity and mortality comparing low- and high-volume hospitals (4.0% vs. 4.8%; p = 0.85).

CONCLUSIONS

Low-volume hospitals may achieve good results for surgical treatment of UIAs. The results indicate that defining numeric operative volume thresholds is not feasible to guide centralization of aneurysm treatment.

Surgical clipping as the preferred treatment for aneurysms of the middle cerebral artery

OBJECTIVE

In recent years the endovascular treatment of intracranial aneurysms (coiling) has progressively gained recognition, particularly after the publication of the International Subarachnoid Aneurysm Trial (ISAT) in 2002. Despite the fact that in ISAT middle cerebral artery (MCA) aneurysms were clearly underrepresented, the study is often used as an argument to favor coiling above surgery in MCA aneurysms. Taken into account that MCA aneurysms are very well accessible for surgery, a contemporary assessment of the benefits of a preferred surgical strategy for MCA aneurysms was performed in a tertiary neurovascular referral center.

METHODS

A prospectively kept single-center database of 151 consecutive patients with an MCA aneurysm was reviewed over a 6-year period (2001-2006). Long-term follow-up after surgical treatment of a ruptured MCA aneurysm was obtained in 74 out of 77 (96%) patients. The outcome was compared with relevant series in the literature.

RESULTS

After a mean follow-up of 4.7 years, 59 out of 74 surgically treated patients (80%) with a ruptured MCA aneurysm had a good outcome (mRankin 0-2). All patients with an unruptured MCA aneurysm also had a good outcome after clipping. This is well-matched with the findings of the literature search, and competitive with the endovascular results.

CONCLUSION

Surgical clipping is recommended as the principal treatment strategy for MCA aneurysms. This is not only ethically defendable in view of the surgical results but also in line with a strategy to maintain surgical experience within centralized neurovascular centers.

Coil embolization of unruptured middle cerebral artery aneurysms

BACKGROUND

Since the International Subarachnoid Aneurysmal Trial, endovascular coiling has been increasingly used as primary treatment option for ruptured or unruptured aneurysms that are feasible for coiling.

OBJECTIVE

To evaluate the feasibility and clinical and angiographic outcomes of coiling for unruptured middle cerebral artery aneurysms.

METHODS

The records of 70 consecutive patients with 76 unruptured middle cerebral artery aneurysms who underwent coiling were retrospectively evaluated.

RESULTS

Thirty-one aneurysms were treated by single-catheter, 18 by multicatheter, 11 by balloon-assisted, 13 by stent-assisted, and 3 by a combination of multicatheter and balloon-assisted techniques. Coiling was accomplished in 75 but failed in 1 aneurysm. One patient died of consequences of subarachnoid hemorrhage occurring 9 hours after coiling. One intraprocedural aneurysm rupture occurred, which was controlled by further coil insertions and left no sequelae. There were 1 cortical infarction and 1 basal ganglia infarction, both of which recovered completely. Treatment-related permanent morbidity and mortality rates were 0% and 1.4%, respectively. Postembolization control angiography revealed 40 complete, 30 neck remnant, and 5 incomplete occlusions. Clinical follow-up was available in all patients (mean, 25 months; range, 7-105 months). There was no subarachnoid hemorrhage during follow-up, but 1 death resulting from acute myocardial infarction occurred 3 months after coiling. None of the surviving patients had any neurological deterioration. Follow-up angiography was available in 69 aneurysms at 6 to 24 months (mean, 12 months). Three major and 6 minor recurrences were detected. All 3 major recurrent aneurysms were re-treated by coiling without any complications.

CONCLUSION

Most unruptured middle cerebral artery aneurysms could be safely treated by coiling with acceptable short-term to midterm outcomes. Our results warrant further study with a longer follow-up period in a larger population.

Trends over time in the management of 2253 patients with cerebral aneurysms: A single practice experience

BACKGROUND

To better understand the longitudinal trend in the proportion of techniques employed for cerebral aneurysm treatment, we reviewed our experience with 2253 patients over the last 11 years.

METHODS

We reviewed data in our prospective aneurysm database for all consecutive patients treated from January 1998 through December 2009. Data regarding age, sex, aneurysm location, presence or absence of hemorrhage, Fisher grade, clinical grade, treatment methods, length of hospitalization, and mortality rates by the time of discharge were retrieved and retrospectively analyzed. The most common aneurysm types were subsequently classified and analyzed separately.

RESULTS

The patient population included 663 males (29%) and 1590 females (71%). A total of 2253 patients presented with 3413 aneurysms; 1523 (63%) of the aneurysms were diagnosed as aneurysmal subarachnoid hemorrhage. A total of 2411 (71%) aneurysms were treated. Overall, 645 (27%) of the 2411 aneurysms underwent endosaccular coiling and 1766 (73%) underwent clip ligation; 69 (3%) of these aneurysms required both treatment modalities. The percentage of all aneurysms treated by endosaccular coiling increased from 8% (21) in 1998 to 28% (87) in 2009. There was no statistical difference between the average length of hospitalization for patients who underwent endosaccular coiling and clip ligation for their ruptured (P = 0.19) and unruptured (P = 0.80) aneurysms during this time period.

CONCLUSIONS

In our practice, endovascular treatment has continued to be more frequently employed to treat cerebral aneurysms. This technique has had the greatest proportional increase in the treatment of posterior circulation aneurysms.

The keyhole concept in aneurysm surgery: results of the past 20 years

BACKGROUND

Improvements in preoperative imaging and intraoperative visualization have led to a refinement in surgical techniques.

OBJECTIVE

Report of a 20-year experience with application of the keyhole technique as a contribution to the ongoing debate on the impact of limited craniotomies in aneurysm surgery.

METHODS

Over a 20-year period, 1000 consecutive patients with 1297 aneurysms were surgically treated in 1062 operations: 651 in the acute stage after SAH and 411 with unruptured aneurysms. The outcome was assessed with the modified Rankin scale and approach-related complications.

RESULTS

The majority of the cases were treated by 4 different keyhole approaches: The supraorbital approach was used in 793 patients for 989 aneurysms, the subtemporal in 48 patients for 50 aneurysms, the interhemispheric in 46 patients for 51 aneurysms, and the retromastoidal in 55 patients for 55 aneurysms. In 120 patients, the classic pterional approach was applied to treat 152 aneurysms. The results of unruptured aneurysms were good (modified Rankin scale ≤ 2) in 96.52%. The complication rates of the keyhole approaches were less than in the pterional group, although the difference did not reach statistical significance.

CONCLUSION

The overall outcome, rate of retreatment, and approach-related complications with keyhole approaches for the management of ruptured and unruptured aneurysms are comparable to recently published conventional surgical aneurysm series. In addition to the common benefits of limited-exposure approaches, this series demonstrates appropriate safety and applicability of the keyhole technique in aneurysm surgery.

A novel aneurysm clip design for atheromatous, thrombotic, or previously coiled lesions: preliminary experience with the "compression clip" in 6 cases

BACKGROUND

Large and giant lesions often have thicker, atheromatous walls as well as intra-aneurysmal thrombus that combine to prevent traditional clips from closing properly in some cases.

OBJECTIVE

To report the development and use of a novel clip design specifically tailored to treat atheromatous, thrombotic, or previously coiled aneurysms.

METHODS

We retrospectively reviewed the records of 6 patients with complex aneurysms not amenable to simple neck clipping and not considered appropriate for endovascular therapy who were treated using a novel "compression" clip design. We describe the development and use of a novel aneurysm clip design with blades that are not opposed at rest to allow direct clipping of atheromatous, thrombotic, and previously coiled aneurysms.

RESULTS

Four patients had recurrent, previously coiled aneurysms; one of these also had a large thrombotic component. Two patients had complex lesions with heavy atheroma involving a portion of their aneurysms. There were no complications related to the use of the clip, and all patients did well without neurological complications. In every case, the clip allowed straightforward obliteration of the aneurysm without the need for temporary vascular occlusion, aneurysmorrhaphy, or removal of an intra-aneurysmal coil mass. All patients underwent intraoperative angiography to confirm obliteration of the aneurysm with preservation of the normal vasculature.

CONCLUSION

Atheromatous, thrombotic, and previously coiled aneurysms may not be treatable with simple neck clipping and may not be curable with endovascular therapy. For such cases, we designed a novel "compression" clip that has been used safely and successfully in our experience with good short-term follow-up.

Lessons learned by personal failures in aneurysm surgery: what went wrong, and why?

PURPOSE

To analyse the intraoperative complications of a single neurosurgeon, with emphasis on devastating intraoperative incidents, and how they possibly could have been avoided.

METHODS

All the patients operated upon by the author between 1986 and 2002, i.e. 252 patients with 270 craniotomies for 294 aneurysms, were included. All intraoperative events that possibly could have influenced the clinical outcome were recorded prospectively.

RESULTS

A total of 16 cases (6.3% of all the patients) with serious intraoperative incidents were identified. In 11 cases (3.6% of all aneurysms), an intraoperative rupture occurred that was judged to have had mild to severe consequences for the patient. In another four patients (1.6% of all patients), all with unruptured, large aneurysms (>15 mm) of the carotid or middle cerebral arteries, a major vessel occlusion occurred inadvertently. In one patient with a large, unruptured MCA aneurysm, a clip slipped after the closure of the wound, causing a fatal intracerebral haemorrhage. These events had a severe impact on the clinical outcome. In retrospect, most of these incidents could, and should have, been avoided.

CONCLUSIONS

It is recommended to start the training of new aneurysm surgeons on patients with small, supratentorial, unruptured aneurysms, followed by ruptured aneurysms in all other supratentorial locations than the anterior communicating artery (ACOM), which is the supratentorial location that should be the last step in the training of independent aneurysm surgeons.

Endovascular treatment of 174 middle cerebral artery aneurysms: clinical outcome and radiologic results at long-term follow-up

PURPOSE

To retrospectively evaluate the immediate safety and efficacy as well as the clinical outcome and long-term angiographic results of endovascular treatment (EVT) of middle cerebral artery (MCA) aneurysms.

MATERIALS AND METHODS

This is a retrospective review of patients in whom coiling of MCA aneurysms was attempted over a 7-year period. Institutional review board approval and informed written consent were obtained. This study included 153 patients (90 women, 63 men; mean age, 49.5 years +/- 11.7 [standard deviation]) with 174 MCA aneurysms (71 unruptured, 103 ruptured). Complications of EVT, clinical outcome, and the results of either cerebral digital subtraction angiography (DSA) or magnetic resonance (MR) angiography were analyzed at initial, intermediate (6-18 months), and late (2-7 years) follow-up.

RESULTS

Coiling was performed in 160 (92%) aneurysms in 141 patients. Periprocedural complications were observed in 31 (19.4%) procedures, including aneurysm perforations (n = 7, 4.4%) and thromboembolic events (n = 24, 15.0%). EVT induced permanent morbidity in eight (5.7%) patients, with severe neurologic impairment in three (2.1%) and two deaths (1.4%). Of 114 MCA aneurysms controlled by using DSA (n = 50) or MR angiography (n = 64) at 50 months +/- 14, 73 (64%) remained completely occluded, 31 (27.2%) recurred, and 12 (10.5%) major recurrences were retreated. A balloon remodeling technique allowed treatment of complex aneurysms (n = 63) but was associated with more recurrences in the long term (42.6%) than aneurysms treated without balloon assistance (16.4%; P = .016).

CONCLUSION

EVT of MCA aneurysms was safe and long-term monitoring of patients showed a low rate of recurrence requiring retreatment. However, complex anatomy and long-term recurrences have to be addressed when considering EVT for MCA aneurysms.

Vascular neurosurgery following the International Subarachnoid Aneurysm Trial: modern practice reflected by subspecialization

OBJECT

In this paper the authors' goal was to report on and examine (in the context of a large hospital with good endovascular intervention provisions) the activities of a neurosurgeon with a dedicated vascular interest in the era after the International Subarachnoid Aneurysm Trial in the United Kingdom. They also aimed to establish therapeutic trends and outcomes.

METHODS

The authors reviewed the multidisciplinary team activity of 1 neurosurgeon and 2 interventional radiologists during a period of 22 months (2005-2007). They reviewed 281 aneurysm interventions; the majority was used to treat subarachnoid hemorrhage. Data analysis showed a strong preference for endovascular treatment for acute rupture (86.6 vs 13.4%), with a progressively greater role for open microsurgery in the more elective context (57% endovascular vs 43% surgical). They also reviewed 66 interventions for arteriovenous malformations, of which only 6 were surgical. These data are compared against a sample year from 2001 to 2002 (pre-International Subarachnoid Aneurysm Trial), showing comparable rates of surgically treated aneurysms versus endovascularly treated aneurysms, but an increase overall in the number of patients requiring open surgery.

RESULTS

The authors found that excellent outcomes for microsurgical clipping compared with endovascular therapy can be achieved within the current climate. These and previously published data strongly support a continuing role for vascular neurosurgery as a subspecialist interest in combination with a dedicated endovascular service and a multidisciplinary team.

CONCLUSIONS

Despite a trend to prefer coiling for ruptured aneurysms, the authors have shown that there is still a vital role for open surgery in the management of the ruptured and unruptured aneurysm. They consider the remaining role for surgery for arteriovenous malformations within the modern era of endovascular therapy.