Long-Term Outcomes of Surgical Clipping of Woven EndoBridge-Eligible Middle Cerebral Artery Bifurcation Aneurysms

Operative Neurosurgery 30:18–25, 2026

This clinical study evaluates long-term outcomes of microsurgical clipping for middle cerebral artery (MCA) wide-neck bifurcation aneurysms that meet radiographic criteria for treatment with the Woven EndoBridge (WEB) device. Using a retrospective review of a prospectively maintained registry, the authors compare functional outcomes, complication rates, recurrence, and retreatment against published WEB and clipping cohorts.

Results show high surgical efficacy: 99% treatment success, 94.1% of unruptured cases achieving final mRS ≤2, a 4.9% morbidity rate, and 0% mortality, with lower retreatment and higher complete occlusion rates than reported WEB series. The authors conclude microsurgical clipping remains a reliable option for MCA WNBAs and recommend location-specific subgroup analyses in future WEB studies.

Microsurgical Clipping Outcomes: Surgical clipping of WEB-eligible middle cerebral artery (MCA) wide-necked bifurcation aneurysms (WNBAs) achieved a 99% treatment success rate, 4.9% morbidity, 0% mortality, and 94.1% good functional outcomes (mRS ≤2) in unruptured cases, with low recurrence and retreatment rates.

Comparison to WEB Device: Clipping resulted in higher complete occlusion rates, lower retreatment rates, and lower thromboembolic complication rates compared to endovascular treatment with the Woven EndoBridge (WEB) device for MCA WNBAs.

Functional Outcomes: Both ruptured and unruptured aneurysms treated surgically showed excellent or improved functional status at follow-up, with 91.8% of unruptured and 94.1% of ruptured cases experiencing stable or improved mRS scores.

Complication Profile: Thromboembolic complications occurred in 5.9% of unruptured cases, with permanent neurological deficits in 4.9% and no surgical mortality; intraoperative rupture was rare (2.0%).

Limitations of WEB Evidence: Most WEB studies pooled multiple aneurysm locations, making it difficult to assess location-specific efficacy; at the MCA, WEB showed higher retreatment and thromboembolic rates than clipping, and lower rates of complete occlusion.

Treatment Selection: MCA aneurysms are often suitable for surgical clipping due to their accessible location and favorable anatomy, especially at experienced centers, supporting a “clip-first” approach for many MCA WNBAs.

Study Limitations: Findings are based on a retrospective, single-center cohort at a high-volume academic institution, limiting generalizability and direct comparison to randomized or multicenter WEB trials.

Clinical Recommendation: Both clipping and WEB are effective for MCA WNBAs, but surgical clipping may offer superior durability and occlusion; treatment choice should be individualized through shared decision-making, not solely based on minimally invasive appeal.

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.

Basal vein of Rosenthal classification: the key to venous outflow of the deep sylvian fissure

J Neurosurg 141:154–164, 2024

Mastery of sylvian fissure dissection is essential to access lesions within the deep basal cisterns. The deep sylvian vein and its tributaries play a major role during access to and beyond the carotid cistern through the sylvian fissure and determine the complexity of microdissection. Preserving the venous outflow during sylvian fissure dissection is the best reliable strategy to prevent postoperative venous strokes or venous hypertension. The authors report the role of the basal vein of Rosenthal (BVR) in the venous outflow pattern of the deep sylvian cistern.

METHODS The authors analyzed 262 consecutive surgical cases involving sylvian fissure dissection from 2015 to 2017. Inclusion criteria were complete sylvian fissure dissection for the treatment of intracranial aneurysms. Exclusion criteria were giant size (aneurysm diameter > 24 mm), meningitis, subarachnoid hemorrhage within the sylvian cistern, absence of 4D CT angiography, and previous surgery. Retrospective radiological and operative video reviews were carried out to assess the association between the superficial sylvian vein and the BVR. The authors analyzed the course of the BVR and the patterns of venous drainage of the sylvian cistern. The surgical difficulty of sylvian fissure dissection was rated by the authors to study the operative significance of the venous patterns encountered. Two clinical cases are described to illustrate the proposed BVR classification.

RESULTS A total of 97 patients met the selection criteria. The most frequent type of BVR was immature (diameter < 0.5 mm, 68%). When the BVR was incompletely developed or absent (immature type), the deep sylvian veins drained through a middle sylvian vein in 70% of cases, requiring advanced sylvian fissure dissection techniques. However, when the BVR was completely developed (32%), the middle sylvian vein was found in a minority of cases (6%), which allowed for an unobstructed transsylvian corridor. Interrater and test-retest reliability of the surgical difficulty was greater than 0.9.

CONCLUSIONS Preoperative assessment of the BVR anatomy is key to predict the deep sylvian venous pattern. The authors provide objective evidence supporting the reciprocal relationship between the type of BVR and the presence of a middle sylvian vein and the deep sylvian venous outflow. An immature BVR should alert the neurosurgeon of the high likelihood of finding a complex deep venous pattern, which may drive surgical planning.

Reversal of Middle Cerebral Artery Stenosis by Minimally Invasive Intracerebral Hematoma Evacuation

Neurosurgery Practice 2024;5(2):e00087.

Acute intracerebral hematomas are known to induce significant mass effects within the brain, leading to critical complications such as cerebral midline shift, herniation, and increased intracranial pressure. The timing and efficacy of intracerebral hematoma evacuation remain subjects of ongoing debate in current literature.

CLINICAL PRESENTATION: In our case report, we present a 74-year-old female patient diagnosed with basal ganglia hematoma. The resultant mass effect from the intracerebral hematoma led to middle cerebral artery (MCA) stenosis. Notably, early-stage minimally invasive hematoma evacuation was pivotal in facilitating successful revascularization of the MCA.

CONCLUSION: Our case underscores the significance of prompt identification and management of MCA stenosis arising from intracerebral hematoma. Early intervention through minimally invasive hematoma evacuation proved instrumental in achieving successful MCA revascularization. These findings emphasize the critical role of timely interventions in mitigating potential complications associated with intracerebral hematoma.

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.

Microsurgical treatment of unruptured middle cerebral artery aneurysms

J Neurosurg 130:1498–1504, 2019

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.

Computer-aided analysis of middle cerebral artery tortuosity: association with aneurysm development

J Neurosurg 130:1478–1484, 2019

Blood vessel tortuosity may play an important role in the development of vessel abnormalities such as aneurysms. Currently, however, there are no studies analyzing the impact of brain blood vessel tortuosity on the risk of aneurysm formation. Therefore, the authors performed a computer-aided analysis of middle cerebral artery (MCA) tortuosity, especially among patients diagnosed with MCA aneurysms.

METHODS Anatomy of the MCAs of 54 patients with unruptured MCA aneurysms was retrospectively analyzed, as was that of 54 sex-, age-, and vessel side–matched control patients without MCA aneurysms. From medical records, the authors obtained each patient’s medical history including previous and current diseases and medications. For each patient, they calculated the following tortuosity descriptors: relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD), and inflection count metric (ICM).

RESULTS Patients with an MCA aneurysm had significantly lower RLs (0.75 ± 0.09 vs 0.83 ± 0.08, p < 0.01), SOAMs (0.45 ± 0.10 vs 0.60 ± 0.17, p < 0.01), and PADs (0.34 ± 0.09 vs 0.50 ± 0.17, p < 0.01). They also had significantly higher TIs (0.87 ± 0.04 vs 0.81 ± 0.07, p < 0.01) and ICMs (3.07 ± 1.58 vs 2.26 ± 1.12, p < 0.01). Female patients had significantly higher RLs (0.76 ± 0.11 vs 0.80 ± 0.09, p = 0.03) than male patients.

CONCLUSIONS Middle cerebral artery aneurysm formation is strongly associated with blood vessel tortuosity parameters, which can potentially be used to screen for patients at risk for MCA aneurysm formation.

 

Computer-aided analysis of middle cerebral artery tortuosity: association with aneurysm development

J Neurosurg 130:1478–1484, 2019

Blood vessel tortuosity may play an important role in the development of vessel abnormalities such as aneurysms. Currently, however, there are no studies analyzing the impact of brain blood vessel tortuosity on the risk of aneurysm formation. Therefore, the authors performed a computer-aided analysis of middle cerebral artery (MCA) tortuosity, especially among patients diagnosed with MCA aneurysms.

METHODS Anatomy of the MCAs of 54 patients with unruptured MCA aneurysms was retrospectively analyzed, as was that of 54 sex-, age-, and vessel side–matched control patients without MCA aneurysms. From medical records, the authors obtained each patient’s medical history including previous and current diseases and medications. For each patient, they calculated the following tortuosity descriptors: relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD), and inflection count metric (ICM).

RESULTS Patients with an MCA aneurysm had significantly lower RLs (0.75 ± 0.09 vs 0.83 ± 0.08, p < 0.01), SOAMs (0.45 ± 0.10 vs 0.60 ± 0.17, p < 0.01), and PADs (0.34 ± 0.09 vs 0.50 ± 0.17, p < 0.01). They also had significantly higher TIs (0.87 ± 0.04 vs 0.81 ± 0.07, p < 0.01) and ICMs (3.07 ± 1.58 vs 2.26 ± 1.12, p < 0.01). Female patients had significantly higher RLs (0.76 ± 0.11 vs 0.80 ± 0.09, p = 0.03) than male patients.

CONCLUSIONS Middle cerebral artery aneurysm formation is strongly associated with blood vessel tortuosity parameters, which can potentially be used to screen for patients at risk for MCA aneurysm formation.

Keyhole strategy aiming at minimizing hospital stay for surgical clipping of unruptured middle cerebral artery aneurysms

J Neurosurg 130:1359–1366, 2019

Aneurysms of the middle cerebral artery (MCA) are still most often treated by clipping through standard craniotomy, but a longer hospital stay is one of the main drawbacks of this treatment. The authors developed a pterional keyhole clipping strategy for unruptured MCA aneurysms with the intention of minimizing hospital stay. In this paper, they report on their experience with this approach and analyze the long-term neurological and radiological outcomes.

METHODS A total of 160 relatively small unruptured MCA aneurysms (mean 6.4 mm) were clipped through the pterional keyhole approach (19–30 mm, mean 24.6 mm) in 149 patients (aged 34–79 years, mean 62 years). Neurological and cognitive function were examined by several scales, including the modified Rankin Scale (mRS) and Mini–Mental State Examination (MMSE). Patients’ level of depression was assessed using the Beck Depression Inventory and Hamilton Depression Scale. The state of clipping was assessed at 1 year and then every few years after the operation.

RESULTS The mean duration of postoperative hospitalization was 2.3 ± 3.4 days; in 31.3% of the cases, the patients were discharged on the day after the operation (overnight hospital stay) and in 93.2% within 3 days. Of the patients younger than 60 years, 40.4% required only an overnight stay. Complete aneurysm neck clipping was confirmed in 157 cases (98.1%). None of the completely clipped aneurysms showed any recurrence during the mean follow-up period of 5.0 years. The mean length of clinical follow-up was 5.4 years. After 2 (1.3%) of the surgical procedures, the patients showed persistent neurological deficits, defined as mRS score 1, but the overall operative morbidity based on the International Study of Unruptured Intracranial Aneurysms (ISUIA) definition (mRS score ≥ 2 or MMSE score < 24) was 0% at the last examination. Depression scores were significantly improved after surgery, and in 85.6% of the cases the patients were satisfied with their cosmetic results.

CONCLUSIONS Pterional keyhole clipping is less invasive than clipping via standard craniotomy, minimizes hospital stay, and achieves durable treatment for relatively small unruptured MCA aneurysms.

 

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

Neurosurgery 83:879–889, 2018

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 randomeffects 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.

 

Morphological and Hemodynamic Differences Between Aneurysmal Middle Cerebral Artery Bifurcation and Contralateral Nonaneurysmal Anatomy

Neurosurgery 81:779–786, 2017

The morphological and hemodynamic features differ between middle cerebral artery (MCA) bifurcations with and without aneurysms.

OBJECTIVE: To investigate the morphological and hemodynamic differences between aneurysmal MCA bifurcation and contralateral nonaneurysmal anatomy.

METHODS: Computed tomography angiography of 36 patients with unilateral small saccular MCA bifurcation aneurysms was evaluated. The parent–daughter angles (ϕ1 for larger branch and ϕ2 for smaller branch), bifurcation angle (ϕ = ϕ1 + ϕ2), inclination angle (γ angle), and their relationships with the MCA bifurcation locations were analyzed. Computational fluid dynamics simulation was performed in 6 cases to explore the hemodynamics influenced by the bifurcation morphology.

RESULTS: The ϕ angle was significantly higher in aneurysmal than contralateral nonaneurysmal bifurcations (160.8◦ ± 31.0◦ vs 99.0◦ ± 19.2◦, respectively; P = .000); the ϕ1, ϕ2, and γ angles were also higher. However, by regression analysis combined with MCA bifurcation locations, only the ϕ angle might be associated with the aneurysm presence (odds ratio = 1.120, 95% confidence interval = 1.059-1.185) and a ϕ angle cut-off of 124.8◦ was established. Computational fluid dynamics simulation demonstrated that flow resistance of the wider aneurysmal MCA bifurcation was significantly higher than that on the contralateral side.

CONCLUSION: A larger ϕ angle was more prevalent in aneurysmal than nonaneurysmal MCA bifurcations, and the higher flow resistance caused by the larger ϕ angle might be a potential hemodynamic factor associated with MCA aneurysm presence.

Predictive factors for decompressive hemicraniectomy in malignant middle cerebral artery infarction

Predictive factors for decompressive hemicraniectomy in malignant middle cerebral artery infarction

Acta Neurochir (2016) 158:865–873

The mortality rate of patients with brain oedema after malignant middle cerebral artery (MCA) infarction approaches 80 % without surgical intervention. Surgical treatment with ipsilateral decompressive hemicraniectomy (DHC) has been shown to dramatically improve survival rates. DHC currently lacks established inclusion criteria and additional research is needed to assess the impact of prognostic factors on functional outcome. The aim of this study was to assess the impact of prognostic factors on functional outcome.

Method A retrospective cohort study was carried out including 46 patients who underwent DHC at the Karolinska University Hospital between 2004 and 2014. The maximum time to surgery was 5 days after symptom debut. The primary endpoint was a dichotomised score on the modified Rankin Scale (mRS) 3 months after surgery, with favourable outcome defined as mRS ≤ 4.

Results When the study population was dichotomised according to the primary endpoint, a significant difference between the groups was seen in preoperative Glasgow Coma Score (GCS), blood glucose levels and the infarction’s involvement of the basal ganglia (p <0.05). In a logistic regression model, preoperative GCS contributed significantly with a 59.6 % increase in the probability of favourable outcome for each point gained in preoperative GCS (p=0.035).

Conclusions The results indicate that preoperative GCS, blood glucose and the infarction’s involvement of the basal ganglia are strong predictors of clinical outcome. These factors should be considered when assessing the probable outcome of DHC, and additional research based on these factors may contribute to improved inclusion criteria for DHC.

Ideal clipping methods for unruptured middle cerebral artery bifurcation aneurysms based on aneurysmal neck classification

MCAb aneurysms clipping

Neurosurg Rev (2016) 39:215–224

Endovascular coiling is widely used for many cerebral aneurysms; however, in cases of middle cerebral artery bifurcation (MCBIF) aneurysms, it is associated with a higher incidence of unfavorable outcomes compared to microsurgical clippings. In this retrospective study, we aimed to investigate the outcomes of microsurgical clipping for unruptured MCBIF aneurysms and determine the ideal clipping methods for different aneurysm subtypes.

From January 2011 to December 2013, 203 aneurysms with saccular shape (<25 mm) were treated by an experienced neurosurgeon. Depending on the involvement of the aneurysmal thin wall, the aneurysm neck was classified as follows: subtype I, limited bifurcation; subtype II, progressed to M1 trunk; subtype III, progressed to M2 trunk; subtype IV, progressed to M1 and one M2 trunk; and subtype V, progressed to M1 and two M2 trunks. The clipping methods included simple, sliding, interlocking, or mixed approaches.

Aneurysm clippings were accomplished without any morbidity in all cases, and seven cases had a minimal neck remnant. The following clipping methods were predominantly used: subtype I, simple (90.2 %) and sliding (8.8 %) (mean = 1.2 clips); subtype II, interlocking (51.4 %), sliding (30.0 %), mixed (15.7 %), and simple (2.9 %) (2.4 clips); subtype III, simple (57.5 %) and sliding (42.5 %) (1.5 clips); subtype IV, interlocking (64.3 %) (2.1 clips), simple (10.7 %), sliding (14.3 %), and mixed (10.7 %); and subtype V, interlocking (50.0 %), sliding (35.7 %), and mixed (14.3 %) methods with multiple clips (2.8 clips).

If an appropriate clipping method is selected according to the neck classification, satisfactory surgical obliteration can be achieved for unruptured MCBIF aneurysms without morbidity.

Morphological Parameters Associated With Middle Cerebral Artery Aneurysms

Morphological Parameters Associated With Middle Cerebral Artery Aneurysms

Neurosurgery 76:721–727, 2015

Morphological factors contribute to the hemodynamics of the middle cerebral artery (MCA).

OBJECTIVE: To identify image-based morphological parameters that correlated with the presence of MCA aneurysms.

METHODS: Image-based anatomic parameters obtained from 110 patients with and without MCA bifurcation aneurysms were evaluated with Slicer, an open-source image analysis software, to generate 3-dimensional models of the aneurysms and surrounding vascular architecture. We examined segment lengths, diameters, and vessel-to-vessel angles of the parent and daughter vessels at the MCA bifurcation. In order to reduce confounding by genetic and clinical risk factors, 2 control groups were selected: group A (the unaffected contralateral side of patients with unilateral MCA bifurcation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Univariate and multivariate analyses were performed to determine statistical significance.

RESULTS: One hundred ten patients who were evaluated from 2007 to 2014 were analyzed (73 patients with MCA aneurysms and 37 control patients). Multivariate analysis revealed that a smaller parent artery diameter (group A: odds ratio [OR] 0.20, P < .01, group B: OR 0.23, P < .01) and a larger daughter-to-daughter branch angle (group A: OR 1.01, P = .04, group B: OR 1.02, P = .04) were most strongly associated with MCA aneurysm presence after adjusting for other morphological factors.

CONCLUSION: Smaller parent artery diameter and larger daughter-to-daughter branch angles are associated with the presence of MCA bifurcation aneurysms. These easily measurable parameters may provide objective metrics to assess aneurysm formation and growth risk stratification in high-risk patients.

Surgical Management of Ruptured Middle Cerebral Artery Aneurysms With Large Intraparenchymal or Sylvian Fissure Hematomas

Ruptured MCA aneurysms

Neurosurgery 76:258–264, 2015

Craniotomy for hematoma evacuation and aneurysm clipping is the treatment modality of choice for ruptured middle cerebral artery (MCA) aneurysms with intracranial hematomas. Recent literature suggests that endovascular coil embolization followed by hematoma evacuation can be an acceptable alternative.

OBJECTIVE: To determine neurological outcomes in patients with ruptured MCA aneurysms and intraparenchymal or sylvian fissure hematomas.

METHODS: The records of 49 patients with ruptured MCA aneurysms with large intracranial hematomas treated with hematoma evacuation and aneurysm clipping between January 2000 and December 2013 were retrospectively reviewed.

RESULTS: Within this cohort, 35 patients (71.4%) were Hunt and Hess grade IV or V on presentation. The mean hematoma volume was 100.4 6 77.2 mL. Craniectomy was performed in 40 patients (81.6%). Angiographic vasospasm developed in 15 patients (30.6%). The in-hospital mortality rate was 28.6% (14 patients). At a mean of 25.3 6 34.0 months follow-up, a good outcome (modified Rankin Scale [mRS] score 0-3) was observed in 18 patients (36.7%). Significant factors associated with poor outcome or death (mRS scores of 4-6) included increasing age (P , .01), increasing Hunt and Hess grade (P = .03), increasing modified Fisher grade (P = .01), presence of intraventricular hemorrhage (P , .01), decreasing percentage of hematoma evacuation (P , .05), need for craniectomy (P ,. 01), need for external ventricular drainage (P = .04), and angiographic vasospasm (P = .02).

CONCLUSION: MCA aneurysm rupture with concomitant large intraparenchymal or sylvian fissure hematoma formation carries a grave prognosis. Simultaneous hematoma evacuation and aneurysm clipping with or without craniectomy can be an effective treatment modality.

Anatomic Risk Factors for Middle Cerebral Artery Aneurysm Rupture

Anatomic Risk Factors for Middle Cerebral Artery Aneurysm Rupture-1

Neurosurgery 73:825–837, 2013

The middle cerebral artery (MCA) is the most frequent location for unruptured intracranial aneurysms. Controversy remains as to which unruptured MCA aneurysms should be treated prophylactically.

OBJECTIVE: To identify independent topographical and morphological variables that could predict increased rupture risk of MCA aneurysms.

METHODS: A retrospective analysis of computed tomography angiography data of 1009 consecutive patients with 1309 MCA aneurysms, referred between 2000 and 2009 to Helsinki University Hospital, was carried out. Morphological and topographical parameters examined for MCA aneurysms comprised aneurysm wall regularity, size, neck width, aspect ratio, bottleneck factor, height-width ratio, location along the MCA, side, distance from the internal carotid artery bifurcation, and dome projection in axial and coronal computed tomography angiography views. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors for rupture.

RESULTS: Of the 1309 MCA aneurysms, 69% were unruptured and 31% were ruptured. Most unruptured MCA aneurysms were smaller than 7 mm (78%), with a smooth wall (80%) and a height-width ratio of 1 (47%) and were located at the main bifurcation (57%). Ruptured MCA aneurysms, mostly 7 to 14 mm in size (55%), had an irregular wall (78%) and a height-width ratio greater than 1 (72%) and were located at the main bifurcation (77%). Thirty-eight percent of MCA bifurcation aneurysms, 74% of large aneurysms, 64% of aneurysms with an irregular wall, and 49% of aneurysms with a height-width ratio greater than 1 were ruptured.

CONCLUSION: Location at the main MCA bifurcation, wall irregularity, and less spherical geometry were independently associated with rupture of MCA aneurysms with a correlation with aneurysm size.

Complex middle cerebral artery aneurysms. A new classification

Complex MCAA-a new classification

Acta Neurochir (2013) 155:1481–1491

Because of the diversity of aneurysm morphology, complicated arterial anatomy and hemodynamic characteristics, tailored surgical treatments are required for cases of individual complex middle cerebral artery (MCA) aneurysms.

Methods During an 8-year period, 59 complex MCA aneurysms in 58 patients were treated microsurgically in our department. Complex aneurysms were defined as having large (10–24 mm in diameter) or giant (diameter≥25 mm) size or non-saccular morphology (fusiform, dissecting or serpentine).

Results Direct clipping of the aneurysmal necks was achieved in eight patients, while reconstructive clipping was performed in 25 patients. Indirect aneurysm occlusion was performed in 25 cases, including trapping or resecting the aneurysm in four cases, trapping or resecting the aneurysm with extraintracranial (EC) or intra-intracranial (IC) bypass in 21 cases and internal carotid artery (ICA) sacrifice with EC-IC bypass in one case. Forty-eight aneurysms (81.4 %) were completely obliterated. Graft patency was confirmed in 20 of 21 cases (95.2 %) with bypass. A recurrent aneurysm was detected in one case and a re-operation was performed. Two patients with Hunt-Hess grade IV aneurysms died during the perioperative period. Overall, 52 cases (88.1 %) had good outcomes (Glasgow Outcome Scale≥4) during the late follow-up period.

Conclusion The surgical modality and strategy for treating complex MCA aneurysm are decided according to the morphology of the aneurysm, vascular anatomy and the hemodynamic characteristics of each case. Thus, we developed a new classification based on the angioarchitecture. Favorable outcomes can be achieved by treating complex MCA aneurysms with appropriate surgical modalities, strategies and techniques.

Extracranial-Intracranial Bypass and Vessel Occlusion for the Treatment of Unclippable Giant Middle Cerebral Artery Aneurysms

Extracranial_Intracranial_Bypass_and_Vessel

Neurosurgery 72:428–436, 2013

Giant middle cerebral artery (MCA) aneurysms pose management challenges.

OBJECTIVE: To review the outcomes of patients with giant MCA aneurysms not amenable to clipping or vessel reconstruction treated with extracranial-intracranial (EC-IC) bypass and vessel sacrifice.

METHODS: We retrospectively reviewed a database of aneurysms treated at our institution between 1983 and 2011.

RESULTS: Sixteen patients (11 males, 5 females) were identified. There were 10 saccular, 4 fusiform, and 2 serpentine aneurysms. The aneurysms predominantly involved the M1 segment in 5 cases, M2 in 9 cases, and both M1 and M2 in 2 cases. The EC-IC bypasses performed included 13 superficial temporal artery-MCA, 1 saphenous vein graft-MCA, and 2 radial artery grafts-MCA. The postoperative bypass patency rate was 93.8% (15/16). There were 3 cerebrovascular accidents (18.8%), but no perioperative deaths (0% mortality). The mean follow-up was 58.4 months (range, 1-265; median, 23.5 months). In 75% (12/16) of cases the aneurysms were occluded successfully. A small residual was noted in 3 cases with the use of this treatment strategy, and they were re-treated. In a fourth case treated with partial distal occlusion, reduced flow through the aneurysm was noted postoperatively, but the patient did not undergo further treatment. The mean modified Rankin scale and mean Glasgow Outcome Scale scores at last follow-up were 1.6 (range, 1-4; median, 1) and 4.8 (range, 3-5; median, 5), respectively.

CONCLUSION: Giant MCA aneurysms are challenging lesions. EC-IC bypass with parent vessel occlusion can provide a durable form of treatment with acceptable rates of morbidity and mortality.

The intermediate trunk of the middle cerebral artery

J Neurosurg 116:1024–1034, 2012

(http://thejns.org/doi/abs/10.3171/2012.1.JNS111013)

The branching structure of the middle cerebral artery (MCA) remains a debated issue. In this study the authors aimed to describe this branching structure in detail.

Methods. Twenty-seven fresh, human brains (54 hemispheres) obtained from routine autopsies were used. The cerebral arteries were first filled with colored latex and contrast agent, followed by fixation with formaldehyde. All dissections were done under a microscope. During examination, the trunk structures of the MCA and their relations with cortical branches were demonstrated. Lateral radiographs of the same hemispheres were then obtained and comparisons were made. Angles between the MCA trunks were measured on 3D CT cerebral angiography images in 25 patients (50 hemispheres), and their correlations with the angles obtained in the cadaver brains were evaluated.

Results. A new classification was made in relation to the terminology of the intermediate trunk, which is still a subject of debate. The intermediate trunk was present in 61% of cadavers and originated from a superior trunk in 55% and from an inferior trunk in 45%. Cortical branches supplying the motor cortex (precentral, central, and postcentral arteries) significantly originated from the intermediate trunk, and the diameter of the intermediate trunk significantly increased when it originated from the superior trunk. In measurements of the angles between the superior and intermediate trunks, it was found that the intermediate trunk had significant dominance in supplying the motor cortex as the angle increased. The intermediate trunk was classified into 3 types based on the angle values and the distance to the bifurcation point as Group A (pseudotrifurcation type), Group B (proximal type), and Group C (distal type). Group A trunks were seemingly closer to the trifurcation structure that has been reported on in the literature and was seen in 15%. Group B trunks were the most common type (55%), and Group C trunks were characterized as the farthest from the bifurcation point. Group C trunks also had the smallest diameter and fewest cortical branches. Similarities were found between the angles in cadaver specimens and on 3D CT cerebral angiography images. Beyond the separation point of the MCA, trunk structures always included the superior trunk and inferior trunk, and sometimes the intermediate trunk.

Conclusions. Interrelations of these vascular structures and their influences on the cortical branches originating from them are clinically important. The information presented in this study will ensure reliable diagnostic approaches and safer surgical interventions, particularly with MCA selective angiography.

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

Acta Neurochir. DOI 10.1007/s00701-011-1139-6

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.