Role of surgical treatment of intracranial aneurysms in the era of endovascular therapy: a review

Neurosurg Focus 59(6):E2, 2025

This review evaluates the contemporary role of microsurgical clipping versus endovascular treatment (EVT) for intracranial aneurysms, comparing long-term durability, complication profiles, and anatomical or patient factors that guide modality selection. It synthesizes trial data (ISAT, BRAT), meta-analyses, and location-specific outcomes to highlight differences in occlusion, retreatment, and morbidity.

The article also outlines practical considerations—hybrid strategies, cerebral bypass, training needs, economics, and global disparities—arguing for individualized, multidisciplinary decision-making and preserving microsurgical expertise despite growing EVT adoption.

Treatment Goals: Exclusion of intracranial aneurysms from circulation while preserving parent vessels and neural function remains the primary objective; both endovascular treatment (EVT) and microsurgical clipping are core modalities.

Long-term Outcomes: Microsurgical clipping offers greater durability and lower rates of recurrence, rebleeding, and retreatment compared to EVT, which has higher retreatment rates despite lower short-term morbidity.

Procedure Selection: EVT is generally preferred for older patients and posterior circulation aneurysms, while microsurgery is favored in younger patients, those with hematomas, mass effect, and aneurysms of the middle cerebral and pericallosal arteries.

Aneurysm Location: Surgical clipping achieves higher occlusion and lower recurrence, especially for anterior circulation, middle cerebral artery, and complex aneurysms; EVT is more suitable for posterior circulation and anatomically challenging cases.

Complications and Adjuncts: Microsurgery allows for evacuation of hematomas and cisternal blood (reducing vasospasm and hydrocephalus), while EVT avoids craniotomy risks but may induce mechanical vasospasm and requires antiplatelet therapy.

Hybrid and Advanced Techniques: Hybrid approaches (combining EVT and surgery) and cerebral bypass remain essential for complex, giant, or recurrent aneurysms not amenable to standard treatments.

Cost and Access: Microsurgical treatment incurs lower overall healthcare costs than EVT; global disparities exist, with surgical clipping dominating in low-resource settings due to limited endovascular infrastructure.

Decision-Making: Optimal management requires individualized, multidisciplinary evaluation considering patient factors, aneurysm characteristics, and resource availability; no single factor should solely dictate treatment choice

Has a fast treatment transition from surgical to endovascular operations improved the survival of aneurysmal subarachnoid hemorrhage?

Acta Neurochirurgica (2025) 167:34

The study examines the impact of transitioning from surgical to endovascular treatment for aneurysmal subarachnoid hemorrhage (aSAH) at Helsinki University Hospital. Findings suggest that case fatality rate (CFR) reductions may be more attributable to other factors than the treatment shift.

• The study investigates the effects of a rapid transition from surgical to endovascular treatment on case fatality rates (CFRs) of aneurysmal subarachnoid hemorrhage (aSAH) at Helsinki University Hospital (HUH).

• The transition to endovascular treatment occurred in 2015, with two treatment eras defined: surgical (2012–2014) and endovascular (2015–2017).

• Results showed a significant increase in endovascular treatment for non-MCA cases and a consistent surgical treatment for MCA cases, with similar decreases in 1-year CFRs for both groups.

• The study concludes that the independent effect of endovascular treatment on decreasing CFRs is small, suggesting improvements in other factors such as diagnostic modalities and acute care may have contributed more.

• The study highlights the need for a case-specific approach in treating aSAH, as different aneurysm locations may benefit differently from surgical or endovascular treatments.

• The research emphasizes the importance of considering other outcome-related factors in addition to treatment modality when analyzing CFR trends.

Anterior choroidal artery aneurysms: a systematic review and meta-analysis of outcomes and ischemic complications following surgical and endovascular treatment

J Neurosurg 142:127–137, 2025

Anterior choroidal artery (AChA) aneurysms account for 2%–5% of all intracranial aneurysms. Treatment considerations include microsurgical clipping, flow diversion, or coiling with or without adjunctive devices. AChA aneurysms pose challenges in treatment due to the origination of the aneurysm from the origin or proximal segment of the AChA. The AChA is particularly susceptible to vasospasm and occlusion during treatment with devastating neurological deficits, including hemiparesis, hemianesthesia, lethargy, neglect, and hemianopia. In this study, the authors performed a meta-analysis to quantify the outcomes and complication rates across treatment modalities for AChA aneurysms and to identify risk factors reported in the literature.

METHODS The authors performed a systematic review of AChA aneurysms treated with surgical clipping, endovascular coiling, or flow diversion and reported in the PubMed, Embase, Scopus, and Cochrane search databases. Single-arm meta-analyses of the selected outcomes were performed in RStudio.

RESULTS Literature review yielded 25 studies that met the inclusion criteria. In total, 1627 patients were included in the analysis, with 554 males, 1009 females, and 64 unspecified. The rate of any complication in the full cohort was 11.6%, with a rate of ischemic complications of 5.5% and a favorable recovery rate of 90.3% of all patients treated. In total, 1064 patients underwent surgical clipping, 443 were treated with coiling, and 120 patients with flow diversion. In clipped patients, the rate of total surgical complications was 17.6%, with an ischemic complication rate of 9.4%. The rate of good functional recovery, defined on the basis of a Glasgow Outcome Scale score of 4–5 or modified Rankin Scale score of 0–2, was 88.0%, and complete obliteration was achieved in 84.5% of surgically clipped aneurysms. The complication rate in coiled patients was 10.3%, with an ischemic complication rate of 3.0%. Good functional recovery was achieved in 88.6% of coiled patients and complete aneurysm obliteration in 74.1%. Flow diversion resulted in a complication rate of 1.3%, with 0.7% rate of ischemic complications. Good functional recovery was achieved in 98.4% of patients and complete aneurysm obliteration in 79.0% in the flow diversion group. Aneurysm morphological features that impacted the complication rate were also identified to augment quantitative data and to help guide treatment selection for AChA aneurysms.

CONCLUSIONS Flow diversion showed significantly lower total and ischemic complications and improved outcomes compared to clipping and coiling. There may be differences in outcomes between treatment types, especially when considering the varied patient presentations that guide treatment selection.

Comparing surgical clipping with endovascular treatment for unruptured middle cerebral artery aneurysms: a systematic review and updated meta-analysis

J Neurosurg 142:116–126, 2025

Unruptured middle cerebral artery aneurysm (uMCAA) has traditionally been treated with open surgical clipping (SC). Endovascular treatments (EVTs) were designed to reduce surgical risks in these cases. Nevertheless, despite its potential benefits, many surgeons favor SC for uMCAA. This updated meta-analysis aimed to compare the safety, efficacy, and clinical outcomes of SC and EVT for uMCAA.

METHODS The authors searched the Medline, Embase, and Cochrane Library databases according to the Cochrane and PRISMA guidelines. Eligible studies included those with ≥ 4 patients with uMCAA reporting comparative data of SC and EVT. The endpoints were the complete occlusion rate (Raymond class I and II), good clinical outcomes (modified Rankin Scale score ≤ 2 or Glasgow Outcome Scale score ≥ 4), procedure-related complications (further divided into major and minor), and mortality. The authors pooled OR with 95% CI values with a random-effects model. I 2 statistics were used to assess heterogeneity, and sensitivity analysis was conducted to address high heterogeneity. Publication bias was assessed with funnel plot analysis and the Egger’s test.

RESULTS The analysis included data from 10 studies. Regarding the complete occlusion assessment, the comparative analysis revealed OR 0.17 (95% CI 0.08–0.40, p < 0.01), favoring SC. In terms of achieving good clinical outcomes, OR 0.44 (95% CI 0.20–0.97, p < 0.05) was determined, favoring SC. No differences regarding total procedure-related complications, major complications, or mortality were identified. However, a higher likelihood of minor complications was identified for EVT, with OR 4.68 (95% CI 2.01–10.92, p < 0.01).

CONCLUSIONS This systematic review and meta-analysis identified a lower likelihood of complete occlusion at last follow-up and lower likelihood of good clinical outcomes in patients treated with EVT when compared with SC. Furthermore, a higher likelihood of minor complications was identified in patients who underwent EVT when compared with SC. The findings reinforce that, based on the currently available data, SC should be considered the primary approach for treating uMCAA. However, EVT is an evolving approach, and this study’s findings represent a synthesis of observational studies. Randomized trials are warranted to elucidate which approach should be the mainstay for uMCAA and to identify the nuances that determine whether SC or EVT is more or less indicated for addressing uMCAA with consideration of the individuality of each patient and aneurysm.

Optimal Timing of Microsurgical Treatment for Ruptured Arteriovenous Malformations: A Systematic Review and Meta-Analysis

Neurosurgery 96:18–28, 2025

The timing of microsurgical treatment (MST) for ruptured brain arteriovenous malformations (bAVM) is a contentious issue in the literature. This study aimed to investigate the impact of MST timing on outcomes in patients with ruptured bAVMs, considering MST with and without preoperative endovascular treatment (EVT).

METHOD: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, a comprehensive search was conducted across multiple databases, yielding 15 studies meeting the inclusion criteria. The timing was defined as the duration from the rupture of bAVM to the MST. The patients were divided into 4 different groups based on MST timing: <48 hours, <1 week, <2 weeks, and <1 month. The primary outcome was favorable outcome defined as a modified Rankin Scale score of 0 to 2 or a Glasgow Outcome Scale score of 4 to 5 in the last clinical follow-up. Secondary outcomes included periprocedural mortality and complete excision.

RESULTS: MST time >48 hours were associated with a significantly higher favorable outcome rate (odds ratio: 9.71, 95% Cl: 3.09-30.57, P < .01) and a lower mortality rate (OR: 0.15, 95% Cl: 0.02-0.88, P = .04) compared with MST timing ≤48 hours. After exclusion of patients who underwent MST with preoperative EVT, MST time >48 hours had a significantly higher rate of favorable outcome (OR: 9.39, 95% CI: 2.53-34.89, P < .01).

CONCLUSION: This meta-analysis suggests that delayed surgical intervention beyond 48 hours may be associated with improved favorable outcomes in patients who underwent MST with and without preoperative EVT for ruptured bAVMs.

Trends in the size of treated unruptured intracranial aneurysms over 35 years

J Neurosurg 139:1328–1338, 2023

In the absence of clear guidelines and consistent natural history data, the decision to treat unruptured intracranial aneurysms (UIAs) is a matter of some controversy. Currently, decisions are often guided by a consensus of cerebrovascular specialist teams and patient preferences. It is unclear how paradigm-shifting developments in the detection and treatment of UIAs have affected the size of the UIAs that are selected for treatment. Herein, the authors aimed to study potential changes in the average size of the UIAs that were treated over time. They hypothesized that the average size of UIAs that are treated is decreasing over time.

METHODS A systematic search of the literature was performed to identify all studies describing the size of UIAs that were treated using any modality. Scatter diagrams with trend lines were used to plot the size of the aneurysms treated over time and assess for the presence of a potentially significant trend via statistical correlation tests. Subgroup analyses based on type of treatment, country of study, and specialty of the authors were performed.

RESULTS A total of 240 studies including 35,150 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. The mean age of patients was 55.5 years, and 70.7% of the patients were females. There was a significant decrease in the size of treated UIAs over time (Spearman’s r = −0.186, p < 0.001), with a 0.71-mm decrease in the average size of treated UIAs every 5 years since 1987 and an annual mean dropping below 7 mm in 2012. This decreasing trend was present in surgically and endovascularly treated UIAs (p < 0.001 for both), in more developed and developing countries (p < 0.001 for both), within neurosurgical and non-neurosurgical specialties (p < 0.001 for both), most prominently in the US (Spearman’s r = −0.482, p < 0.001), and less prominently in Europe (Spearman’s r = −0.221, p < 0.001) and was not detected in East Asia.

CONCLUSIONS The present study indicates that based on the treated UIA size data published in the literature over the past 35 years, smaller UIAs are being treated over time. This trend is likely driven by safer treatments. However, future studies should elucidate the cost-effectiveness of treating smaller UIAs as well as the possible real-world contribution of this trend in preventing aneurysmal subarachnoid hemorrhage.

Delayed coil migration into oropharynx following endovascular coiling of a traumatic carotid cavernous fistula

Acta Neurochirurgica (2022) 164:1287–1292

Carotid-cavernous fistulas (CCFs) are abnormal vascular shunts between the carotid artery and the cavernous sinus.

A 37-year-old male presented with a traumatic CCF and basal skull fracture extending through the medial wall of the cavernous sinus and sphenoid sinus. The CCF was treated with endovascular coiling.

Three months after this procedure, he was found to have coil migration through the traumatic sphenoid defect into the pharynx. He underwent urgent endonasal endoscopic surgery to disconnect and remove the extruded coil.

Post-operative coil migration is a rare but serious complication following endovascular treatment of traumatic CCF.

Recurrence and risk factors of posterior communicating artery aneurysms after endovascular treatment

Acta Neurochirurgica (2021) 163:2319–2326

Endovascular treatment (EVT) of posterior communicating artery aneurysms (PcomA) is challenging because of posterior communicating artery (Pcom) architecture. Additionally, these aneurysms have a high risk of recanalization compared with those located elsewhere.

Methods The radiographic findings of 171 patients treated with EVT at two institutions were retrospectively reviewed. Univariate and multivariate analyses were performed, and subgroup analyses were performed based on Pcom characteristics.

Results Recanalization of PcomAs occurred in 53 patients (30.9%). Seven patients (4.0%) were retreated (six endovascularly and one with microsurgical clipping). The mean follow-up duration was 27.7 months (range: 3.5–78.6). The maximum diameter (odds ratio [OR] 1.23, P = .006, 95% CI 1.07–1.44), a Raymond–Roy classification of grade II or III (OR 2.26, P = .03, 95% CI 1.08–4.82), and the presence of reinforcement (balloon or/and stent, OR 0.44, P = .03, 95% CI 0.20–0.91) were associated with recanalization using multivariate logistic regression. Significant differences were found in maximum aneurysm diameter (P = .03) between normal- and fetal-type Pcoms on analysis of variance.

Conclusions The recanalization rate of PcomAs after EVT was 30.9%; the retreatment rate was 4.0%. Maximum diameter, Raymond–Roy classification, and presence of reinforcement were significantly associated with recanalization but not associated with fetal-type Pcom. Aneurysm size was larger in patients with a fetal-type Pcom than in those with a normal Pcom. Pcom size was not related to recanalization rate.

Neuroform Atlas Stent for Treatment of Middle Cerebral Artery Aneurysms

Neurosurgery 89:102–108, 2021

Heterogeneous effect of endovascular aneurysm therapy has been observed across different anatomic locations. There is a paucity of data for stent-assisted coiling of middle cerebral artery (MCA) aneurysms.

OBJECTIVE: To present the results of the MCA aneurysmgroup from the Neuroform Atlas (Stryker Neurovascular) investigational device exemption (IDE) trial.

METHODS: The Atlas IDE trial is a prospective, multicenter, single-arm, open-label study of wide-neck aneurysms (neck ≥ 4 mm or dome-to-neck ratio < 2) in the anterior circulation treated with the Neuroform Atlas Stent and approved coils. Follow-up was obtained immediately postprocedure and 2, 6, and 12 mo postoperatively.We herein describe safety and efficacy outcomes, and functional independence of the subjects with aneurysms from all segments of MCA.

RESULTS: A total of 35 patients were included (27 MCA bifurcation, 5 M1, 3 M2). The mean aneurysm size was 6.0 ± 1.8 mm, and the mean neck was 4.4 ± 1.2 mm. Technical procedural success was achieved in all patients. A total of 26 patients had follow-up digital subtraction angiography available at 12mo, with 80.8% (21/26) having complete aneurysm occlusion. Twelve-month safety data were collected for 91.4% (32/35), 8.5% (3/35) had primary safety endpoint, all 3 major ischemic strokes. Mortality occurred in 2 patients beyond 30 d unrelated to procedure (1 gallbladder cancer and 1 fentanyl intoxication). At 1 yr, modified Rankin Score was 0 to 2 in 84.4% (27/32), 3 in 9.4%, and 3 patientswere missing. Approximately 5.7% (2/35) of patients were retreated at 12 mo.

CONCLUSION: Stent-assisted coiling with the Neuroform Atlas Stent is a viable alternative to clipping for selected MCA aneurysms. Complete aneurysm occlusion rates have improved compared to historical data. Proper case selection can lead to acceptable endovascular results.

Predictors of Complications, Functional Outcome, and Morbidity in a Large Cohort TreatedWith Flow Diversion

Neurosurgery DOI:10.1093/neuros/nyz508

A dramatic improvement in obliteration rates of large, wide-necked aneurysms has been observed after the FDA approved the Pipeline Embolization Device (PED) in 2011.

OBJECTIVE: To assess the predictors of complications, morbidity, and unfavorable outcomes in a large cohort of patients with aneurysms treated with PED.

METHODS: A retrospective chart review of a prospectively maintained database for subjects treated with flow diversion from 2010 to 2019.

RESULTS: A total of 598 aneurysms were treated during a period extending from 2010 to 2019 (84.28% females, mean age 55.5 yr, average aneurysm size 8.49 mm). Morbidity occurred at a rate of 5.8% and mortality at a rate of 2.2%. Ischemic stroke occurred at a rate of 3%, delayed aneurysmal rupture (DAR) at 1.2%, and distal intraparenchymal hemorrhage (DIPH) at 1.5%. On multivariate analysis, the predictor of stroke was aneurysm size>15 mm. Predictors of DAR were previous subarachnoid hemorrhage (SAH), increasing aneurysm size, and posterior circulation aneurysm. Predictors of DIPH were using more than 1 PED and baseline P2Y12 value. Predictors of in-stent stenosis were the increasing year of treatment and balloon angioplasty, whereas increasing age and previous treatment were negatively associated with in-stent stenosis. Predictors of morbidity were posterior circulation aneurysms, increasing aneurysm size, and hypertension, and incidental aneurysm diagnosis was protective for morbidity.

CONCLUSION: Flow diversion is a safe and effective treatment option for aneurysms. A better understanding of predictive factors of complications, morbidity, and functional outcomes is of high importance for a more accurate risk assessment.

Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: complications, aneurysm sac occlusion, reabsorption, recurrence, and jailed branch modification at follow-up

J Neurosurg 131:1751–1762, 2019

The purpose of this study is to present the authors’ medium-term results, with special emphasis on complications, occlusion rate of the aneurysm sac (digital subtraction angiography [DSA] and MRI), and the fate of cortical branches and perforating arteries covered (“jailed”) by the flow diverter (FD) stent.

METHODS Between January 2010 and September 2017, 29 patients (14 female) with 30 aneurysms were treated with an FD stent. Twenty-one aneurysms were at the middle cerebral artery bifurcation, 8 were in the anterior communicating artery region, and 1 was a pericallosal artery bifurcation. Thirty-five cortical branches were covered. A single FD stent was used in all patients. Symptomatic and asymptomatic periprocedural and delayed complications were reported. DSA and MRI controls were analyzed to evaluate modification of the aneurysm sac and jailed branches.

RESULTS Permanent morbidity was 3.4% (1/29), due to a jailed branch occlusion, with a modified Rankin Scale (mRS) score of 2 at the last follow-up. Mortality and permanent complication with poor prognosis (mRS score > 2) rates were 0%. The mean follow-up time for DSA and MRI (mean ± SD) was 21 ± 14.5 months (range 3–66 months) and 19 ± 16 months (range 3–41 months), respectively. The mean time to aneurysm sac occlusion (available for 24 patients), including stable remodeling, was 11.8 ± 6 months (median 13, range 3–27 months). The overall occlusion rate was 82.1% (23/28), and it was 91.7% (22/24) in the group of patients with at least 2 DSA control sequences. One recanalization occurred at 41 months posttreatment. At the time of publication, at the latest follow-up, 7 (20%) of 35 covered branches were occluded, 18 (51.4%) showed a decreased caliber, and the remaining 10 (28.5%) were unchanged. MRI T2-weighted sequences showed complete sac reabsorption in 7/29 aneurysms (24.1%), and the remaining lesions were either smaller (55.2%) or unchanged (17.2%). MRI revealed asymptomatic and symptomatic ischemic events in perforator territories in 7/28 (25%) and 4/28 (14.3%) patients, respectively, which were reversible within 24 hours.

CONCLUSIONS Flow diversion of bifurcation aneurysms is feasible, with low rates of permanent morbidity and mortality and high occlusion rates; however, recurrence may occur. Caliber reduction and asymptomatic occlusion of covered cortical branches as well as silent perforator stroke are common. Ischemic complications may occur with no identified predictable factors. MRI controls should be required in all patients to evaluate silent ischemic lesions and aneurysm sac reabsorption over time.

Surgical or endovascular management of ruptured intracranial aneurysms: an agreement study

J Neurosurg 131:25–31, 2019

Ruptured intracranial aneurysms (RIAs) can be managed surgically or endovascularly. In this study, the authors aimed to measure the interobserver agreement in selecting the best management option for various patients with an RIA.

METHODS The authors constructed an electronic portfolio of 42 cases of RIA in which an angiographic image along with a brief clinical vignette for each patient were displayed. Undisclosed to the responders was that the RIAs had been categorized as International Subarachnoid Aneurysm Trial (ISAT) (small, anterior-circulation, non–middle cerebral artery location, n = 18) and non-ISAT (n = 22) aneurysms; the non-ISAT group also included 2 basilar apex aneurysms for which a high number of endovascular choices was expected. The portfolio was sent to 132 clinicians who manage pa- tients with RIAs and circulated to members of an American surgical association. Judges were asked to choose between surgical and endovascular management, to indicate their level of confidence in the choice of treatment on a quantitative 0–10 scale, and to determine whether they would include the patient in a randomized trial in which both treatments are compared. Eleven clinicians were asked to respond twice at least 1 month apart. Responses were analyzed using kappa statistics.

RESULTS Eighty-five clinicians (58 cerebrovascular surgeons, 21 interventional neuroradiologists, and 6 interventional neurologists) answered the questionnaire. Overall, endovascular management was chosen more frequently (n = 2136 [59.8%] of 3570 answers). The proportions of decisions to clip were significantly higher for non-ISAT (50.8%) than for ISAT (26.2%) aneurysms (p = 0.0003). Interjudge agreement was only fair (kappa 0.210, 95% CI 0.158–0.276) for all cases and judges, despite high confidence levels (mean score > 8 for all cases). Agreement was no better within sub- groups of clinicians with the same specialty, years of experience, or location of practice or across capability groups (ability to clip or coil, or both). When agreement was defined as > 80% of responders choosing the same option, agreement occurred for only 7 of 40 cases, all of which were ISAT aneurysms, for which coiling was preferred.

CONCLUSIONS Agreement between clinicians regarding the best management option was infrequent but centered around coiling for some ISAT aneurysms. Surgical clipping was chosen more frequently for non-ISAT aneurysms than for ISAT aneurysms. Patients with such an aneurysm might be candidates for inclusion in randomized trials.

Aneurysm wall enhancement on magnetic resonance imaging as a risk factor for progression of unruptured vertebrobasilar dissecting aneurysms after reconstructive endovascular treatment

J Neurosurg 128:747–755, 2018

The recurrence rate of vertebrobasilar dissecting aneurysms (VBDAs) after reconstructive endovascular treatment (EVT) is relatively high. The aneurysm wall enhancement on high-resolution MRI (HRMRI) reportedly predicts an unsteady state of an intracranial aneurysm. The authors used HRMRI to investigate the relationship between wall enhancement on HRMRI and progression of VBDAs after reconstructive EVT.

METHODS From January 2012 to December 2015, patients with an unruptured VBDA who underwent reconstructive EVT were enrolled in this study. Preoperative enhanced HRMRI was performed to evaluate radiological characteristics. The relationships between aneurysm wall enhancement and various potential risk factors were statistically analyzed. Follow-up angiographic examination was performed with digital subtraction angiography and conventional HRMRI. Cox regression analysis was performed to identify predictors of VBDA progression after reconstructive EVT.

RESULTS Eighty-two patients (12 women and 70 men, mean age 53.48 ± 9.23 years) with 83 VBDAs were evaluated in the current study. The average maximum diameter of the VBDAs was 11.30 ± 7.90 mm. Wall enhancement occurred in 43 VBDAs (51.81%). Among all 83 VBDAs, 62 (74.70%) were treated by stent-assisted coil embolization and 21 (25.30%) by stenting alone. The mean duration of imaging follow-up among all 82 patients was 10.55 months (range 6–45 months), and 15 aneurysms (18.07%) exhibited progression. The statistical analysis indicated no significant differences in age, sex, risk factors (high blood pressure, smoking, diabetes mellitus, and a high cholesterol level), VBDA stage, or VBDA size between enhanced and unenhanced VBDAs. Univariate Cox regression analysis showed that both the maximum diameter of the VBDAs and wall enhancement were associated with recurrence (p < 0.05). Multivariate Cox proportional hazard regression analysis showed that the maximum diameter of the VBDAs and wall enhancement on HRMRI were independent risk factors for aneurysm progression (p < 0.05).

CONCLUSIONS Aneurysm size and wall enhancement on HRMRI can predict the progression of VBDAs after reconstructive EVT.

Validation of a System to Predict Recanalization After Endovascular Treatment of Intracranial Aneurysms

Recanalization-for-Patients-With-Endovascular-Treatment-of-Intracranial-Aneurysms-e1429712894823

Neurosurgery 77:168–174, 2015

With increasing use of endovascular techniques in the treatment of ruptured and unruptured aneurysms, the issue of obliteration efficacy has become increasingly important. We have previously reported the Aneurysm Recanalization Stratification Scale, which uses accessible predictors including aneurysm-specific factors (size, rupture, and intraluminal thrombosis) and treatment-related features (treatment modality and immediate angiographic result) to predict retreatment risk after endovascular therapy.

OBJECTIVE: To assess the external validity of the Aneurysm Recanalization Stratification Scale.

METHODS: External validity was assessed in independent cohorts from 4 centers in the United States and Canada where endovascular and open neurovascular procedures are performed, and in a multicenter cohort of 1543 patients. Probability of retreatment stratified by risk score was derived for each center and the combined multicenter cohort.

RESULTS: Despite moderate variability in retreatment rate among centers (29.5%, 9.9%, 9.6%, 26.3%, 19.7%, and 18.3%), the Aneurysm Recanalization Stratification Scale demonstrated good predictive value with C-statistics of 0.799, 0.943, 0.780, 0.695, 0.755, and 0.719 for each center and the combined cohort, respectively. Probability of retreatment stratified by risk score for the combined cohort is as follows: -2, 4.9%; -1, 5.7%; 0, 5.8%; 1, 13.1%; 2, 19.2%; 3, 34.9%; 4, 32.7%; 5, 73.2%; 6, 89.5%; and 7, 100.0%.

CONCLUSION: Surgical decision-making and patient-centered informed consent require comprehensive and accessible information on treatment efficacy. The Aneurysm Recanalization Stratification Scale is a valid prognostic index. This is the first comprehensive model that has been developed to quantitatively predict retreatment risk following endovascular therapy.

Stratification of Recanalization for Patients With Endovascular Treatment of Intracranial Aneurysms

Recanalization for Patients With Endovascular Treatment of Intracranial Aneurysms

Neurosurgery 76:390–395, 2015

With the increasing use of endovascular techniques in the treatment of both ruptured and unruptured intracranial aneurysms, the issue of obliteration efficacy has become increasingly important.

OBJECTIVE: To systematically develop a comprehensive model for predicting retreatment with various types of endovascular treatment.

METHODS: We retrospectively reviewed medical records that were prospectively collected for 305 patients who received endovascular treatment for intracranial aneurysms from 2007 to 2013. Multivariable logistic regression was performed on candidate predictors identified by univariable screening analysis to detect independent predictors of retreatment. A composite risk score was constructed based on the proportional contribution of independent predictors in the multivariable model.

RESULTS: Size (.10 mm), aneurysm rupture, stent assistance, and posttreatment degree of aneurysm occlusion were independently associated with retreatment, whereas intraluminal thrombosis and flow diversion demonstrated a trend toward retreatment. The Aneurysm Recanalization Stratification Scale was constructed by assigning the following weights to statistically and clinically significant predictors: aneurysm-specific factors: size (.10 mm), 2 points; rupture, 2 points; presence of thrombus, 2 points. Treatment-related factors were stent assistance, 21 point; flow diversion, 22 points; Raymond Roy occlusion class 2, 1 point; Raymond Roy occlusion class 3, 2 points. This scale demonstrated good discrimination with a C-statistic of 0.799.

CONCLUSION: Surgical decision making and patient-centered informed consent require comprehensive and accessible information on treatment efficacy. We constructed the Aneurysm Recanalization Stratification Scale to enhance this decisionmaking process. This is the first comprehensive model that has been developed to quantitatively predict the risk of retreatment after endovascular therapy.

Combined endovascular and surgical treatment of fusiform aneurysms of the basilar artery

Combined endovascular and surgical treatment of fusiform aneurysms of the basilar artery- technical note

Acta Neurochir (2014) 156:53–61

To present the combined treatment of fusiform basilar artery aneurysms consisting of a surgical posterior fossa decompressive craniectomy and ventriculoperitoneal (VP) shunt operation at the same sitting, before the endovascular procedure with telescopic stenting of the aneurysmatic vessel segment in four cases.

Methods Combined treatment involving surgical procedure consisting of ventriculoperitoneal shunt placement for hydrocephalus and an occipital bone craniectomy and C1 vertebrae posterior laminectomy to decompress the posterior fossa in the same session. After surgery, the patients were loaded with acetylsalicylic acid and clopidogrel, and then the endovascular treatment was performed.

Results All of the procedures were performed successfully without technical difficulty. The patients tolerated the procedures well and all cases showed remodelling with the overlapping stent technique. The patients were discharged home with baseline neurological situation and computed tomography (CT) angiography was performed at the 3rd month.

Conclusion This technique is a safer endovascular approach to treating symptomatic fusiform basilar artery aneurysms by protecting patients from both the haemorrhagic complications of anticoagulant therapy and thrombotic complications due to the interruption of anticoagulant therapy, while treating the hydrocephalus and compression by surgical means.

Hypoglossal canal dural arteriovenous fistula

Hypoglossal canal dural arteriovenous fistula

J Neurosurg 119:955–960, 2013

The purpose of this study was to evaluate the incidence, radiographic findings, relationship between presenting symptoms for treatment and drainage pattern, and treatment outcomes of hypoglossal canal dural arteriovenous fistula (HC-dAVF).

Methods. During a 16-year period, 238 patients underwent endovascular treatment for cranial dAVF at a single center. The incidence, radiographic findings, relationship between presenting symptoms for treatment and drainage pattern, and treatment outcomes of HC-dAVF were retrospectively evaluated.

Results. The incidence of HC-dAVF was 4.2% (n = 10). Initial symptoms were tinnitus with headache (n = 6), tinnitus only (n = 1), ocular symptoms (n = 1), otalgia (n = 1), and congestive myelopathy (n = 1). Presenting symptoms requiring treatment included ocular symptoms (n = 4), hypoglossal nerve palsy (n = 4), aggravation of myelopathy (n = 1), and aggravation of tinnitus with headache (n = 1). While the affected HC was widened in 4 of 10 patients, hypersignal intensity on source images was conspicuous in all 7 patients who underwent MR angiography (MRA). All ocular symptoms and congestive myelopathy were associated with predominant drainage to superior ophthalmic or perimedullary veins due to antegrade drainage restriction. All patients who underwent transvenous coil embolization (n = 8) or transarterial N-butyl cyanoacrylate (NBCA) embolization (n = 1) improved without recurrence. One patient who underwent transarterial particle embolization had a recurrence 12 months posttreatment and was retreated with transvenous embolization.

Conclusions. The incidence of HC-dAVF was 4.2% of all cranial dAVF patients who underwent endovascular treatment. Source images of MRA helped to accurately diagnose HC-dAVF. More aggressive symptoms may develop as a result of a change in the predominant drainage route due to the development of venous stenosis or obstruction over time. Transvenous coil embolization appears to be the first treatment of choice.

Factors predicting retreatment and residual aneurysms at 1 year after endovascular coiling for ruptured cerebral aneurysms: Prospective Registry of Subarachnoid Aneurysms Treatment (PRESAT) in Japan

Neuroradiology (2012) 54:597–606. DOI 10.1007/s00234-011-0945-0

Endovascular treatment of cerebral aneurysms includes follow-up imaging to identify aneurysms that may need retreatment. The aim of this study was to determine predictors of incomplete aneurysm occlusion at 1 year after endovascular coiling for ruptured cerebral aneurysms.
Methods In 129 patients of the Prospective Registry of Subarachnoid Aneurysms Treatment cohort, ruptured aneurysms were coiled within 14 days of onset and both initial post-coiling and 1-year follow-up digital subtraction angiography or magnetic resonance angiography were obtained. Factors predicting 1-year incomplete aneurysm occlusion (retreatment within 1-year or residual aneurysms at 1 year) were determined using multivariate logistic regression analyses.
Results One-year incomplete aneurysm occlusion was identified in 59 patients, including ten patients who were retreated within 1-year post-coiling. Dome size ≥7.5 mm (P=0.007, odds ratio (OR)=5.00, 95% confidence interval (CI)=1.55– 16.15), pre-treatment aneurysm re-rupture (P=0.023, OR= 3.50, 95% CI=1.19–10.31), non-small size/small neck aneurysm (dome size, ≥10 mm or neck size, ≥4 mm; P= 0.022, OR=3.26, 95% CI=1.19–8.96), and residual aneurysms on immediate post-coiling angiograms (P=0.017, OR= 1.43, 95% CI=1.07–1.93) significantly predicted incomplete aneurysm occlusion at 1-year post-coiling.
Conclusions In addition to the characteristics of aneurysm and initially incomplete aneurysm occlusion, this study showed pre-treatment aneurysm re-rupture to be a predictor that favors closer imaging follow-ups for coiled aneurysms.

Management of Residual and Recurrent Aneurysms After Initial Endovascular Treatment

Neurosurgery 70:537–554, 2012 DOI: 10.1227/NEU.0b013e3182350da5

Coil instability possibly translating into higher delayed rebleeding rates remains a concern in the endovascular management of cerebral aneurysms.

OBJECTIVE: To report on 127 patients with endovascular aneurysmal remnants who underwent re-treatment over an 18 year period.

METHODS: Patients presenting with aneurysm residuals .20% of the original lesion, unstable neck remnants, aneurysmal regrowth, or new aneurysmal daughter sacs were treated by an individualized approach, using both endovascular and surgical techniques.

RESULTS: Seventy-five aneurysmal remnants (59.1%) were treated by further re-embolization. Standard coil embolization was used in 65 cases, stent-protected coiling in 9 cases, and balloon remodeled coiling in 1 case, respectively. Fifty-two (40.9%) aneurysmal remnants were treated surgically. Standard microsurgical clipping was used in 44 patients, parent artery occlusion or trapping under bypass protection in 5 cases, deliberate clipping of the basilar artery trunk in 2 cases, and aneurysm wrapping in one case, respectively. Mechanisms of aneurysm recurrence were coil compaction in 93 cases and regrowth in 34 cases. A single reembolization was sufficient to occlude 78.7% of recurrences from coil compaction, but only 14.3% of recurrences from aneurysm regrowth.

CONCLUSION: The individualized approach resulted in complete occlusion of 114 aneurysms (89.7%), with neck remnants and residual aneurysms detectable in 11 (8.7%) and 2 (1.6%) cases, respectively. Treatment morbidity was 11.9%, without significant differences between surgical (15.6%) and endovascular (9.3%) patients (P = .09). Recurrences from coil compaction were safely treated by re-embolization, whereas recurrences from aneurysmal regrowth may best be managed surgically when technically feasible.