Basilar artery perforator rupture as the cause of perimesencephalic subarachnoid hemorrhage

J Neurosurg 144:1271–1277, 2026

This clinical study evaluates the etiology of perimesencephalic subarachnoid hemorrhage (pmSAH) by applying high-resolution cone-beam CT (CBCT) during catheter angiography to detect basilar artery perforator outpouchings. The retrospective analysis of 22 pmSAH patients found that CBCT identified basilar perforator pseudoaneurysms in a substantial subset, with conservative management yielding excellent outcomes.

The authors argue that many pmSAHs may be arterial rather than venous in origin when imaged with modern high-resolution CBCT protocols. They recommend heightened suspicion for an arterial source and detailed angiographic CBCT acquisition, while acknowledging limits of retrospective design, variable imaging quality, and unresolved management questions.

Objective High-resolution CBCT performed during catheter angiography was used to better identify the etiology of perimesencephalic SAH (pmSAH), challenging the historical assumption of a venous source.

Methods Retrospective review of pmSAH cases (Jan 2023–Dec 2024) requiring catheter angiography with available, diagnostic-quality CBCT; images were interpreted by two experienced neuroangiographers to consensus.

Cohort Of 152 spontaneous SAH presentations, 22 met Rinkel criteria for pmSAH; after exclusions (alternative causes found, missing/low-quality CBCT), 13 patients remained for CBCT-based imaging analysis.

Key finding In 8/13 (61.5%) analyzed pmSAH cases, CBCT showed a basilar artery perforator focal outpouching consistent with a rupture site (submillimeter, 0.4–0.8 mm).

Anatomy distribution Among the 8 identified perforator lesions, 6 were rostral basilar perforators, with 1 midbasilar and 1 caudal perforator involvement.

Outcomes All pmSAH patients—including those with identified basilar perforator outpouchings—had excellent recovery, with no re-rupture events and no clinically significant vasospasm reported in the series.

Follow-up imaging In patients who underwent follow-up DSA with CBCT, the basilar perforator finding resolved on follow-up imaging.

Conclusion/implication pmSAH should be approached with high suspicion for an arterial etiology (basilar perforator pseudoaneurysm frequently detectable with high-resolution CBCT), and conservative management was associated with excellent outcomes in this cohort.

A 7-Year Experience in Microsurgical Treatment of Unruptured Intracranial Aneurysms in Older Patients

Neurosurgery 98:1325–1338, 2026

This article reports a 7-year single-center retrospective analysis comparing one-year neurological outcomes after microsurgical clipping of unruptured intracranial aneurysms in patients >65 years versus younger adults. It details patient selection, aneurysm characteristics, statistical methods, and primary endpoint assessment using the modified Rankin Scale.

Findings indicate similar favorable 1-year outcomes between older and younger cohorts, with diabetes and de novo aneurysm formation/growth identified as independent predictors of poor outcome in the older group. The discussion contextualizes results against endovascular options, comorbidity considerations, and limitations of retrospective single-center data.

Question addressed Whether to treat unruptured intracranial aneurysms (UIAs) in patients >65 remains controversial because of frailty/comorbidities and procedural risk vs rupture risk under conservative management.

Study design Retrospective review of UIA patients treated with microsurgical clipping (single quaternary center, 2014–2020), including only those with admission mRS ≤2; primary endpoint was 1-year mRS, with poor outcome defined as mRS >2.

Cohort 390 total surgically treated patients; 132 (34%) were >65 with mean age 71±4 years.

Main outcome No significant difference in poor neurological outcome at 1 year between older vs younger patients (11% vs 9.3%, P=.82), indicating comparable functional outcomes after microsurgery in selected older adults.

Aneurysm differences with age Older patients had larger aneurysm dimensions and more calcification (e.g., calcification 15% vs 2.8%) and higher PHASES/ELAPSS scores than younger patients.

Univariate risk factors (older group) Factors associated with poor 1-year outcome included diabetes, higher Charlson Comorbidity Index, calcification, treating multiple aneurysms, de novo formation/growth, and higher aspect ratio.

Independent predictors On multivariable analysis in older patients, only diabetes (OR 19.1, P=.02) and de novo formation or growth (OR 12.7, P=.02) predicted poor neurological outcome.

Clinical implication Chronological age alone is not a stand-alone contraindication to microsurgical treatment; individualized selection and comorbidity/risk stratification (notably diabetes and aneurysm growth patterns) are key.

Machine Learning–Based Rupture Risk Prediction for Intracranial Aneurysms: A Systematic Review and Meta-Analysis

Neurosurgery 97:1072–1082, 2025

This systematic review and meta-analysis evaluates machine learning (ML) applications for predicting intracranial aneurysm rupture, comparing 124 ML models across 36 retrospective studies (22,462 patients) with the PHASES score. Results show ML—especially deep learning and SVM—achieves higher AUC and specificity than PHASES, with hemodynamic inputs improving test-set specificity but not external validation.

The authors highlight methodological heterogeneity, risks of bias, and overfitting concerns from retrospective single‑center data, urging prospective, standardized studies and external validation before clinical integration of ML rupture‑risk tools.

Machine Learning (ML) Models: ML techniques, including deep learning (DL), support vector machines (SVM), and regression models, show higher specificity and overall diagnostic accuracy than the traditional PHASES score for predicting intracranial aneurysm rupture risk, with comparable sensitivity.

• Deep Learning Performance: DL models achieved the highest sensitivity (up to 0.87), specificity (up to 0.86), and area under the curve (AUC-ROC up to 0.92) among all ML families, indicating strong discriminative ability in rupture risk prediction.

• PHASES Score Limitations: The PHASES score, though widely used, demonstrates lower specificity (0.51) and modest overall discriminative ability (AUC-ROC 0.66), and does not incorporate important risk factors like aneurysm morphology or family history.

• Hemodynamic Parameters: Incorporating hemodynamic variables (e.g., wall shear stress, flow patterns) into ML models improves specificity and accuracy in test sets, but benefits are less pronounced in external validation, possibly due to sample size and generalizability issues.

• Retrospective Data and Overfitting: All included ML models were trained on retrospective, post-rupture data, raising concerns about overfitting and the applicability of these models to pre-rupture clinical decision-making.

• Generalizability Concerns: ML models often perform less well on external validation data due to biases in patient selection, single-center data, and differences in imaging or clinical protocols, while the PHASES score maintains more consistent performance across settings.

• Need for Prospective Validation: There is a critical need for prospective studies and standardized protocols to confirm the clinical utility and reliability of ML-based rupture risk prediction models before integration into routine practice.

• Clinical Implications: ML approaches, especially DL and SVM, have the potential to enhance individualized risk stratification and reduce overtreatment, but methodological challenges and validation in diverse populations remain essential for safe clinical adoption.

Novel Delivery System Significantly Improves Technical Success and Safety of the Endovascular Clip System (eCLIPs) While Maintaining Efficacy for the Treatment of Wide-Necked Bifurcation Aneurysms

Neurosurgery 97:963–970, 2025

A prospective registry study found that the new eCLIPs electrolytic bifurcation system (eB) for wide-necked bifurcation aneurysms significantly improved technical success and safety over the prior generation, while maintaining high efficacy, with 96% satisfactory occlusion and low rates of neurological complications and retreatment.

• The eCLIPs device is an endovascular implant designed to treat wide-necked bifurcation aneurysms (WNBAs).

• This study compares two generations: the first-generation eCLIPs bifurcation remodeling system (eBRS) and the newer eCLIPs electrolytic bifurcation system (eB).

• A prospective registry included 280 patients; the eB system showed higher implantation success (92% vs 81% for eBRS, P = .007).

• Both systems achieved high rates of satisfactory aneurysm occlusion (mRROC 1+2: 96%).

• The eB system had lower all-cause (1.1%) and neurological (0.5%) death rates compared to eBRS (7% and 5%, respectively).

• Stroke and repeat procedure rates were low for both devices, with eB performing better (stroke: ~1.7%, repeat procedure: 2.2% vs 8.9% for eBRS).

• eCLIPs compares favorably in safety and efficacy to other devices like WEB and stent-assisted coiling.

• The eB system offers improved procedural success and safety, making eCLIPs a strong option for WNBAs; further studies are recommended.

Microsurgical management of 883 previously coiled intracranial aneurysms

J Neurosurg 143:654–667, 2025

This systematic review and meta-analysis found that microsurgical management of previously coiled intracranial aneurysms is effective and safe in well-selected patients, achieving high complete occlusion and good functional outcomes, especially with delayed direct clipping, small aneurysm size, and anterior location.

• Microsurgical management of previously coiled intracranial aneurysms (IAs) is effective and safe in well-selected patients.

• Meta-analysis included 874 patients with 883 previously coiled IAs; most underwent direct clipping.

• Complete occlusion rate was 97.2%, good functional outcome 82.9%, and perioperative mortality 3.7%.

• Direct clipping had the best safety and efficacy, with the lowest rates of complications and highest rates of good outcomes.

• Smaller, anteriorly located, and unruptured aneurysms were associated with the most favorable outcomes.

• Early microsurgery (within 1 month of coiling) and Gurian group C IAs had higher perioperative death rates.

• Key management factors: IA size, location, rupture status, indication, and timing/type of microsurgery.

• Most studies were retrospective case series, limiting subgroup analysis and introducing some heterogeneity.

Natural history of dolichoectatic vertebrobasilar aneurysms: a multinational study

J Neurosurg 142:1376–1386, 2025

This multinational study of 382 patients reveals dolichoectatic vertebrobasilar aneurysms (DVBAs) have a high annual mortality (10.8%) and morbidity (1.6%). Advanced age (>50 years), basilar artery location, and large aneurysm size predict worse outcomes, supporting early invasive treatment when feasible to improve prognosis.

• Dolichoectatic vertebrobasilar aneurysms (DVBAs) are rare, malignant vascular lesions with high morbidity and mortality.

• Largest multinational study to date analyzed 382 patients with DVBAs from 11 centers in Europe, US, and Japan.

• Most patients were male (68.6%), median age at diagnosis was 58.8 years.

• Annual adverse event, mortality, and morbidity rates were 12.4%, 10.8%, and 1.6% respectively.

• Older age (>50 years), basilar artery location, larger aneurysm size (>25 mm), and type II (dolichoectatic) morphology were key risk factors for poor outcomes.

• Highest risk of adverse events and death occurred within the first year after diagnosis, especially in older patients and those with basilar artery involvement.

• Early invasive treatment is encouraged when feasible, based on age and radiological characteristics.

• Study highlights urgent need for new, safer therapeutic options for DVBAs.

Subtemporal Approach for the Treatment of Ruptured and Unruptured Distal Basilar Artery Aneurysms: Is There a Contemporary Use?

Operative Neurosurgery 27:581–596, 2024

Distal basilar artery aneurysms (DBAs) are high-risk lesions for which endovascular treatment is preferred because of their deep location, yet indications for open clipping nonetheless remain. The subtemporal approach allows for early proximal control and direct visualization of critical posterior perforating arteries, especially for posterior-projecting aneurysms. Our objective was to describe our clinical experience with the subtemporal approach for clipping DBAs in the evolving endovascular era.

METHODS: This was a retrospective, single-institution case series of patients with DBAs treated with microsurgery over a 21-year period (2002-2023). Demographic, clinical, and surgical data were collected for analysis.

RESULTS: Twenty-seven patients underwent clipping of 11 ruptured and 16 unruptured DBAs with a subtemporal approach (24 female; mean age 53 years). Ten patients had expanded craniotomies for treatment of additional aneurysms. The aneurysm occlusion rate was 100%. Good neurological outcomes as defined by the modified Rankin Scale score ≤2 and Glasgow Outcome Scale score ≥4 were achieved in 21/27 patients (78%). Two patients died before hospital discharge, one from vasospasm-induced strokes and another from an intraoperative myocardial infarction.

CONCLUSION: These results demonstrate that microsurgical clip ligation of DBAs using the subtemporal approach remains a viable option for complex lesions not amenable to endovascular management.

The impact of regular aspirin use on aneurysm recanalization rates after endovascular coiling

J Neurosurg 141:1020–1025, 2024

Intracranial aneurysms (IAs) pose a significant health risk, often leading to subarachnoid hemorrhage and severe neurological outcomes. Endovascular coiling has been a principal treatment method, but it comes with the challenge of high recanalization rates. Aspirin has recently emerged as a potential agent to reduce these rates. In this study, the authors aimed to investigate the impact of regular aspirin use on aneurysm recanalization rates following endovascular coiling in a 10-year single-institution study.

METHODS A retrospective analysis was conducted on a dataset of 2236 aneurysms treated by a single neurosurgeon over a period of 10 years. The primary outcome measure was aneurysm recanalization, defined by a change in the Raymond-Roy Occlusion Classification of at least one grade.

RESULTS A total of 525 aneurysms were coiled, 109 of which involved patients who reported regular use of aspirin. The recanalization rate was significantly lower in the aspirin group (9.2%) compared with the control group (23.6%) (OR 0.33, 95% CI 0.15–0.66; p = 0.001). On analysis of the specific mechanisms of recanalization, aneurysm sac growth was less frequent in the aspirin group (5.5%) compared with the control group (18%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002). Additionally, patients in the control group had a higher retreatment rate (18%) than patients in the aspirin group (5.5%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002).

CONCLUSIONS Regular use of aspirin appears to be associated with reduced rates of aneurysm recanalization after endovascular coiling. However, caution is advised in interpretation of these results given the retrospective nature of this study. Further randomized controlled trials are needed to confirm these findings.

Incidence and Characteristics of Cerebral Infarction After Microsurgical Clipping of Unruptured Anterior Circulation Cerebral Aneurysms

Neurosurgery 95:798–806, 2024

Postclipping cerebral infarction (PCI) remains a major concern after treatment for unruptured intracranial aneurysms (UIAs). However, studies of microsurgical clipping based on diffusion-weighted imaging are limited. We aimed to present the incidence, risk factors, and types of PCI and its radiological and clinical characteristics.

METHODS: This was a retrospective single-center study in which patients were scheduled to undergo microsurgical clipping for anterior circulation UIAs. The overall incidence and risk factors were calculated. Based on the operation and relevant artery, we categorized PCI on diffusion-weighted imaging into 4 types and presented their radiological and clinical characteristics.

RESULTS: We reviewed the radiological and clinical data of 605 patients. The overall incidence of PCI was 16.7% (101/ 605), of which asymptomatic infarction was 14.9% (90/605) and symptomatic infarction was 1.8% (11/605). Hypertension (adjusted odds ratio [aOR], 2.258; 95% confidence interval [CI]: 1.330-3.833), temporary clipping (aOR, 1.690; 95% CI: 1.034-2.760), multiple aneurysm locations (aOR, 1.832; 95% CI: 1.084-3.095), and aneurysm dome size (aOR, 1.094; 95% CI: 1.006-1.190) were independent risk factors for PCI. Type II (perianeurysmal perforator) infarction was the most common type of PCI (48.6%) and the most common cause of symptomatic infarction (72.7%). Types II and III (distal embolic) infarctions correlated with atherosclerotic changes in the aneurysm wall and temporary clipping (62.4% and 70.6%, respectively). The type IV (unrelated) infarction group had a higher incidence of systemic atherosclerosis (55%).

CONCLUSION: Microsurgical clipping is a safe and viable option for the treatment of anterior circulation UIAs. However, modification of the surgical technique, preoperative radiological assessment, and patient selection are required to reduce the incidence of PCI.

Stent-assisted Woven EndoBridge device for the treatment of intracranial aneurysms: an international multicenter study

J Neurosurg 140:1071–1079, 2024

The Woven EndoBridge (WEB) device is an intrasaccular flow disruptor designed for wide-necked bifurcation aneurysms. These aneurysms may require the use of a concomitant stent. The objective of this study was to determine the clinical and radiological outcomes of patients undergoing stent-assisted WEB treatment. In addition, the authors also sought to determine the predictors of a concomitant stent in aneurysms treated with the WEB device.

METHODS The data for this study were taken from the WorldWideWEB Consortium, an international multicenter cohort including patients treated with the WEB device. Aneurysms were classified into two groups based on treatment: stent-assisted WEB and WEB device alone. The authors compared clinical and radiological outcomes of both groups. Univariable and multivariable binary logistic regression analyses were performed to determine factors that predispose to stent use.

RESULTS The study included 691 intracranial aneurysms (31 with stents and 660 without stents) treated with the WEB device. The adequate occlusion status did not differ between the two groups at the latest follow-up (83.3% vs 85.6%, p =0.915). Patients who underwent stenting had more thromboembolic (32.3% vs 6.5%, p < 0.001) and procedural (16.1% vs 3.0%, p < 0.001) complications. Aneurysms treated with a concomitant stent had wider necks, greater heights, and lower dome-to-neck ratios. Increasing neck size was the only significant predictor for stent use.

CONCLUSIONS This study demonstrates that there is no difference in the degree of aneurysm occlusion between the two groups; however, complications were more frequent in the stent group. In addition, a wider aneurysm neck predisposes to stent assistance in WEB-treated aneurysms.

Visual Morbidity in Patients With Ophthalmic Segment Aneurysms Treated With Flow Diverters

Neurosurgery 94:538–544, 2024

Flow diverter (FD) treatment for aneurysms of the ophthalmic segment of the internal carotid artery (ICA) may raise concerns about visual morbidity related to coverage of the ophthalmic artery by the device. Our objective was to evaluate clinical and angiographic outcomes associated with FD treatment of these aneurysms, with particular emphasis on visual morbidity.

METHODS: We performed a retrospective analysis of the endovascular databases at 2 US centers to identify consecutive patients with aneurysms along the ophthalmic segment of the ICA that were treated with FDs between January 2010 and December 2022. Baseline demographics, aneurysm characteristics, and periprocedural and postprocedural data, including the occurrence of visual complications, were collected.

RESULTS: One hundred and thirteen patients with 113 aneurysms were identified for inclusion in this study. The mean age of the patients was 59.5 ± 12.4 years, and 103 (91.2%) were women. The ophthalmic artery origin was involved in 40 (35.4%) aneurysms, consisting of a neck origin in 33 (29.2%) and a dome origin in 7 (6.2%). New transient visual morbidity during the hospital stay included impaired visual acuity or blurriness in 1 (0.9%) patient, diplopia in 1 (0.9%), and floaters in 1 (0.9%). New transient visual morbidity during follow-up included impaired visual acuity or blurriness in 5 patients (4.4%), diplopia in 3 (2.7%), ipsilateral visual field defect in 1 (0.9%), and floaters in 6 (5.3%). Permanent visual morbidity occurred in 1 patient (0.9%). Among the 101 patients who had angiographic follow-up, the Raymond-Roy occlusion classifications were I (complete aneurysm occlusion) in 85 (84.2%), II (residual neck) in 11 (10.9%), and III (residual aneurysm) in 5 (4.9%).

CONCLUSION: In our experience, flow diversion for ICA ophthalmic segment aneurysms resulted in low rates of visual morbidity, which was mostly transient in occurrence.

Formation of internal carotid artery aneurysms following gamma knife radiosurgery for pituitary adenomas

Acta Neurochirurgica (2023) 165:2257–2265

Only two aneurysm formations in the internal carotid artery after gamma knife radiosurgery (GKRS) for pituitary adenomas are reported so far.

Here, out of the 482 patients who underwent GKRS for pituitary adenomas at our institute, at least five developed aneurysms within the area of high single-dose irradiation. Three patients presented with epistaxis due to aneurysmal rupture and one presented with abducens paralysis due to nerve compression, while one was asymptomatic.

The interval between irradiation and aneurysmal detection ranged from 14 to 21 years. Aneurysm formation in those conditions may be higher than previously thought.

Cisternal Score: A Radiographic Score to Predict Ventriculoperitoneal Shunt Requirement in Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 93:75–83, 2023

Persistent hydrocephalus requiring a ventriculoperitoneal shunt (VPS) can complicate the management of aneurysmal subarachnoid hemorrhage (aSAH). Identification of high-risk patients may guide external ventricular drain management.

OBJECTIVE: To identify early radiographic predictors for persistent hydrocephalus requiring VPS placement. METHODS: In a 2-center retrospective study, we compared radiographic features on admission noncontrast head computed tomography scans of patients with aSAH requiring a VPS to those who did not, at 2 referral academic centers from 2016 through 2021. We quantified blood clot thickness in the basal cisterns including interpeduncular, ambient, crural, prepontine, interhemispheric cisterns, and bilateral Sylvian fissures. We then created the cisternal score (CISCO) using features that were significantly different between groups.

RESULTS: We included 229 survivors (mean age 55.6 years [SD 13.1]; 63% female) of whom 50 (22%) required VPS. CISCO was greater in patients who required a VPS than those who did not (median 4, IQR 3-6 vs 2, IQR 1-4; P < .001). Higher CISCO was associated with higher odds of developing persistent hydrocephalus with VPS requirement (odds ratio 1.6 per point increase, 95% CI 1.34-1.9; P < .001), independent of age, Hunt and Hess grades, and modified GRAEB scores. CISCO had higher accuracy in predicting VPS requirement (area under the curve 0.75, 95% CI 0.68-0.82) compared with other predictors present on admission.

CONCLUSION: Cisternal blood clot quantification on admission noncontrast head computed tomography scan is feasible and can be used in predicting persistent hydrocephalus with VPS requirement in patients with aSAH. Future prospective studies are recommended to further validate this tool.

Endoscopic clipping of an anterior communicating artery aneurysm

Acta Neurochirurgica (2023) 165:1227–1231

Anterior communicating artery aneurysms are most prone to rupture. Surgically, they are conventionally being managed by a pterional approach. Some neurosurgeons prefer a supraorbital keyhole approach in select cases. Fully endoscopic clipping of such aneurysms is seldom described.

Method We clipped an antero-inferiorly directed anterior communicating artery aneurysm endoscopically via a supraorbital keyhole approach. The intraoperative aneurysmal rupture was also managed endoscopically. The patient made an excellent postoperative recovery without any neurological deficits.

Conclusion Select cases of anterior communicating artery aneurysms can be clipped endoscopically using standard instruments and adhering to the basic principles of aneurysm clipping.

A quantitative model to differentiate nonaneurysmal perimesencephalic subarachnoid hemorrhage from aneurysmal etiology

J Neurosurg 138:165–172, 2023

OBJECTIVE Nonaneurysmal perimesencephalic subarachnoid hemorrhage (pmSAH) is considered to have a lower-risk pattern than other types of subarachnoid hemorrhage (SAH). However, a minority of patients with pmSAH may harbor a causative posterior circulation aneurysm. To exclude this possibility, many institutions pursue exhaustive imaging. In this study the authors aimed to develop a novel predictive model based on initial noncontrast head CT (NCHCT) features to differentiate pmSAH from aneurysmal causes.

METHODS The authors retrospectively reviewed patients admitted to an academic center for treatment of a suspected aneurysmal SAH (aSAH) during the period from 2016 to 2021. Patients with a final diagnosis of pmSAH or posterior circulation aSAH were included. Using NCHCT, the thickness (continuous variable) and location of blood in basal cisterns and sylvian fissures (categorical variables) were compared between groups. A scoring system was created using features that were significantly different between groups. Receiver operating characteristic curve analysis was used to measure the accuracy of this model in predicting aneurysmal etiology. A separate patient cohort was used for external validation of this model.

RESULTS Of 420 SAH cases, 48 patients with pmSAH and 37 with posterior circulation aSAH were identified. Blood thickness measurements in the crural and ambient cisterns and interhemispheric and sylvian fissures and degree of extension into the sylvian fissure were all significantly different between groups (all p < 0.001). The authors developed a 10-point scoring model to predict aneurysmal causes with high accuracy (area under the curve [AUC] 0.99; 95% CI 0.98–1.00; OR per point increase 10; 95% CI 2.18–46.4). External validation resulted in persistently high accuracy (AUC 0.97; 95% CI 0.92–1.00) of this model.

CONCLUSIONS A risk stratification score using initial blood clot burden may accurately differentiate between aneurysmal and nonaneurysmal pmSAH. Larger prospective studies are encouraged to further validate this quantitative tool.

Prevalence of incidental intracranial findings on magnetic resonance imaging: a systematic review and meta‑analysis

Acta Neurochirurgica (2022) 164:2751–2765

As the volume and fidelity of magnetic resonance imaging (MRI) of the brain increase, observation of incidental findings may also increase. We performed a systematic review and meta-analysis to determine the prevalence of various incidental findings.

Methods PubMed/MEDLINE, EMBASE and SCOPUS were searched from inception to May 24, 2021. We identified 6536 citations and included 35 reports of 34 studies, comprising 40,777 participants. A meta-analysis of proportions was performed, and age-stratified estimates for each finding were derived from age-adjusted non-linear models.

Results Vascular abnormalities were observed in 423/35,706 participants (9.1/1000 scans, 95%CI 5.2–14.2), ranging from 2/1000 scans (95%CI 0–7) in 1-year-olds to 16/1000 scans (95%CI 1–43) in 80-year-olds. Of these, 204/34,306 were aneurysms (3.1/1000 scans, 95%CI 1–6.3), which ranged from 0/1000 scans (95%CI 0–5) at 1 year of age to 6/1000 scans (95%CI 3–9) at 60 years. Neoplastic abnormalities were observed in 456/39,040 participants (11.9/1000 scans, 95%CI 7.5–17.2), ranging from 0.2/1000 scans (95%CI 0–10) in 1-year-olds to 34/1000 scans (95%CI 12–66) in 80-year-olds. Meningiomas were the most common, in 246/38,076 participants (5.3/1000 scans, 95%CI 2.3–9.5), ranging from 0/1000 scans (95%CI 0–2) in 1-year-olds to 17/1000 scans (95%CI 4–37) in 80-year-olds. Chiari malformations were observed in 109/27,408 participants (3.7/1000 scans, 95%CI 1.8–6.3), pineal cysts in 1176/32,170 (9/1000 scans, 95%CI 1.8–21.4) and arachnoid cysts in 414/36,367 (8.5/1000 scans, 95%CI 5.8–11.8).

Conclusion Incidental findings are common on brain MRI and may result in substantial resource expenditure and patient anxiety but are often of little clinical significance.

Microsurgical treatment of ruptured aneurysms beyond 72 hours after rupture: implications for advanced management

Acta Neurochirurgica (2022) 164:2431–2439

Aneurysmal subarachnoid hemorrhage (aSAH) patients admitted to primary stroke centers are often transferred to neurosurgical and endovascular services at tertiary centers. The effect on microsurgical outcomes of the resultant delay in treatment is unknown. We evaluated microsurgical aSAH treatment > 72 h after the ictus.

Methods All aSAH patients treated at a single tertiary center between August 1, 2007, and July 31, 2019, were retrospectively reviewed. The additional inclusion criterion was the availability of treatment data relative to time of bleed. Patients were grouped based on bleed-to-treatment time as having acute treatment (on or before postbleed day [PBD] 3) or delayed treatment (on or after PBD 4). Propensity adjustments were used to correct for statistically significant confounding covariables.

Results Among 956 aSAH patients, 92 (10%) received delayed surgical treatment (delayed group), and 864 (90%) received acute endovascular or surgical treatment (acute group). Reruptures occurred in 3% (26/864) of the acute group and 1% (1/92) of the delayed group (p = 0.51). After propensity adjustments, the odds of residual aneurysm (OR = 0.09; 95% CI = 0.04–0.17; p < 0.001) or retreatment (OR = 0.14; 95% CI = 0.06–0.29; p < 0.001) was significantly lower among the delayed group. The OR was 0.50 for rerupture, after propensity adjustments, in the delayed setting (p = 0.03). Mean Glasgow Coma Scale scores at admission in the acute and delayed groups were 11.5 and 13.2, respectively (p < 0.001).

Conclusions Delayed microsurgical management of aSAH, if required for definitive treatment, appeared to be noninferior with respect to retreatment, residual, and rerupture events in our cohort after adjusting for initial disease severity and significant confounding variables.

Solid vs. cystic predominance in posterior fossa hemangioblastomas: implications for cerebrovascular risks and patient outcome

Acta Neurochirurgica (2022) 164:1357–1364

Hemangioblastomas (HGBs) are highly vascular benign tumors, commonly located in the posterior fossa, and 80% of them are sporadic. Patients usually present with features of raised intracranial pressure and cerebellar symptoms. HGB can be classified as either mostly cystic or solids. Although the solid component is highly vascularized, aneurysm or hemorrhagic presentation is rarely described, having catastrophic results.

Methods We identified 32 consecutive patients with posterior fossa HBG who underwent surgery from 2008 through 2020 at our medical center. Tumors were classified as predominantly cystic or solid according to radiological features. Resection was defined as gross total (GTR) or subtotal (STR).

Results During the study period, 32 posterior fossa HGBs were resected. There were 26 cerebellar lesions and 4 medullar lesions, and in 2 patients, both structures were affected. Predominant cystic tumors were seen in 15 patients and solids in 17. Preoperative digital subtraction angiography (DSA) was performed in 8 patients with solid tumors, and 4 showed tumor-related aneurysms. Embolization of the tumors was performed in 6 patients, including the four tumor-related aneurysms. GTR was achieved in 29 tumors (91%), and subtotal resection in 3 (9%). Three patients had postoperative lower cranial nerve palsy. Functional status was stable in 5 patients (16%), improved in 24 (75%), and 3 patients (9%) deteriorated. One patient died 2 months after the surgery. Two tumors recurred and underwent a second surgery achieving GTR. The mean follow-up was 42.7 months (SD ± 51.0 months).

Conclusions Predominant cystic HGB is usually easily treated as the surgery is straightforward. Those with a solid predominance present a more complex challenge sharing features similar to arteriovenous malformations. Given the important vascular association of solid predominance HGB with these added risk factors, the preoperative assessment should include DSA, as in arteriovenous malformations, and endovascular intervention should be considered before surgery.

Keywords

Clipping Could Be the Best Treatment Modality for Recurring Anterior Communicating Artery Aneurysms Treated Endovascularly

Neurosurgery 90:627–635, 2022

The anterior communicating artery (AcoA) is the most common location for intracranial aneurysms.

OBJECTIVE: To present occlusion outcomes, complication rate, recurrence rate, and predictors of recurrence in a large cohort with AcoA aneurysms treated primarily with endosaccular embolization. We also attempt to present data on the most effective treatment modality for recurrent AcoA aneurysms.

METHODS: This is a retrospective, single-center study, reviewing the outcomes of 463 AcoA aneurysms treated endovascularly between 2003 and 2018.

RESULTS: The study cohort consisted of 463 patients. Adequate immediate occlusion was achieved in 418 (90.3%). Independent functional status at discharge was observed in 269 patients (58.0%), and the mortality rate was 6.8% (31). At 6 months, adequate occlusion was achieved in 418 (90.4%). Of all the patients, recurrence was observed in 101 cases (21.8%), and of those, 98 (22.4%) underwent retreatment. The combined frequency of retreatment for the coiling group was 42.4%, which was significantly higher than the 0 incident of retreatment in the clipping group (P < .0001). Among the retreatment cohort, there was a significantly higher subsequent retreatment rate in the endovascular group (0% in the clipping group vs 42.4% in the endovascular group, P < .0001).

CONCLUSION: Coiling with and without stent/balloon assistance is a relatively safe and effective modality for the treatment of AcoA aneurysms; however, in the setting of recurrence, microsurgical reconstruction leads to improved outcomes regarding durable occlusion, thus avoiding the potential for multiple interventions in the future.

The added value of cerebrospinal fluid analysis in patients with subarachnoid hemorrhage after negative noncontrast CT

J Neurosurg 136:1024–1028, 2022

In patients presenting within 6 hours after signs and symptoms of suspected subarachnoid hemorrhage (SAH), CSF examination is judged to be no longer necessary if a noncontrast CT (NCCT) scan rules out SAH. In this study, the authors evaluated the performance of NCCT to rule out SAH in patients with positive CSF findings.

METHODS Between January 2006 and April 2018, 1657 patients were admitted with a nontraumatic SAH. Of these patients, 1546 had positive SAH findings on the initial NCCT and 111 patients had an NCCT scan that was reported as negative in the acute setting, but with positive CSF examination for subarachnoid blood. Demographic data, World Federation of Neurosurgical Societies grade, and SAH time points (ictus, time of NCCT, and time of lumbar puncture) were collected. All 111 NCCT scans were reevaluated by an experienced neuroradiologist.

RESULTS Of the 111 patients with positive CSF findings, SAH was initially missed on NCCT in 25 patients (23%). Reevaluation of 21 patients presenting within 6 hours of symptom onset confirmed NCCT negative findings in 12 (5 aneurysms), an aneurysmal SAH (aSAH) pattern in 8 (7 aneurysms), and a perimesencephalic pattern in 1 patient. Reevaluation of 90 patients presenting after 6 hours confirmed negative NCCT findings in 74 patients (37 aneurysms), aSAH pattern in 10 (4 aneurysms), and a perimesencephalic pattern in 6 (2 aneurysms).

CONCLUSIONS CSF examination is still mandatory to rule out SAH as NCCT can fail to show blood, even within 6 hours after symptom onset. In addition, the diagnosis SAH was frequently missed during initial reporting.