Category: Vascular

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Predictive factors for recurrence and clinical outcomes in patients with chronic subdural hematoma

J Neurosurg 127:1117–1125, 2017

Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage in elderly patients. Many studies have suggested various factors that may be associated with the recurrence of CSDH. However, the results are inconsistent. The purpose of this study was to determine the associations among patient factors, recurrence, and clinical outcomes of CSDH after burr hole surgery performed during an 11-year period at twin hospitals.

METHODS Kaplan-Meier analysis was performed to evaluate the risk factors for CSDH recurrence. Univariate and multivariate Cox proportional hazards regression analyses were used to calculate hazard ratios with 95% CIs for CSDH recurrence based on many variables. One-way repeated-measures ANOVA was used to assess the differences in the mean modified Rankin Scale score between categories for each risk factor during each admission and at the last follow-up.

RESULTS This study was a retrospective analysis of 756 consecutive patients with CSDH who underwent burr hole surgery at the Hanyang University Medical Center (Seoul and Guri) between January 1, 2004, and December 31, 2014. During the 6-month follow-up, 104 patients (13.8%) with recurrence after surgery for CSDH were identified. Independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03–2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m2), and a bilateral operation.

CONCLUSIONS This study determined the risk factors for recurrence of CSDH and their effects on outcomes. Further studies are needed to account for these observations and to determine their underlying mechanisms.

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Clinical relevance of anterior cerebral artery asymmetry in aneurysmal subarachnoid hemorrhage

J Neurosurg 127:1070–1076, 2017

An asymmetry of the A1 segments (A1SA) of the anterior cerebral arteries (ACAs) is an assumed risk factor for the development of anterior communicating artery aneurysms (ACoAAs). It is unknown whether A1SA is also clinically relevant after aneurysm rupture. The authors of this study investigated the impact of A1SA on the clinical course and outcome of patients with aneurysmal subarachnoid hemorrhage (SAH).

METHODS The authors retrospectively analyzed data on consecutive SAH patients treated at their institution between January 2005 and December 2012. The occurrence and severity of cerebral infarctions in the ACA territories were evaluated on follow-up CT scans up to 6 weeks after SAH. Moreover, the risk for an unfavorable outcome (defined as > 3 points on the modified Rankin Scale) at 6 months after SAH was assessed.

RESULTS A total of 594 patients were included in the final analysis. An A1SA was identified on digital subtraction angiography studies from 127 patients (21.4%) and was strongly associated with ACoAA (p < 0.0001, OR 13.7). An A1SA independently correlated with the occurrence of ACA infarction in patients with ACoAA (p = 0.047) and in those without an ACoAA (p = 0.015). Among patients undergoing ACoAA coiling, A1SA was independently associated with the severity of ACA infarction (p = 0.023) and unfavorable functional outcome (p = 0.045, OR = 2.4).

CONCLUSIONS An A1SA is a common anatomical variation in SAH patients and is strongly associated with ACoAA. Moreover, the presence of A1SA independently increases the likelihood of ACA infarction. In SAH patients undergoing ACoAA coiling, A1SA carries the risk for severe ACA infarction and thus an unfavorable outcome.

 

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Dexamethasone for chronic subdural haematoma: a systematic review and meta-analysis

Acta Neurochir (2017) 159:2037–2044

Chronic subdural haematoma is a common but retractable neurological disease in the elderly with a high rate of recurrence. Dexamethasone (DX) either as monotherapy or adjuvant therapy has been applied clinically, but its effectiveness and feasibility remain controversial. We conducted this review to clarify this issue. Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference on recurrence rate between DX alone and non-DX therapy or surgical therapy (RR, 0.86; 95% CI, 0.43-1.71; p = 0.66) (RR, 0.89; 95% CI, 0.43-1.85; p = 0.76). Comparison between DX alone with the surgical therapy demonstrated no difference on the poor outcome (RR, 0.40; 95% CI, 0.15-1.04; p = 0.06). Conclusions We had

Conclusions We had no enough evidence to support DX use as an effective alternation to surgical therapy. But adjuvant DX use may facilitate the surgical therapy by reducing recurrence. Further study focusing on adjuvant DX was required.

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Complex Internal Carotid Artery Aneurysm Treated by Extracranial to Intracranial Bypass Using High-Flow Grafts with Therapeutic Internal Carotid Artery Occlusion

Neurosurgery 81:672–679, 2017

Although the extracranial-to-intracranial high-flow bypass (EC-IC HFB) continues to be indispensable for complex aneurysms, the risk factors for the graft occlusion and whether the graft size changes after the bypass have not been well established.

OBJECTIVE: To evaluate the risk factors for the graft occlusion and to confirm whether graft diameters changed over time.

METHODS: The data of 75 patients who suffered from complex internal carotid artery (ICA) aneurysms and were treated by EC-IC HFB using radial artery graft (RAG) or saphenous vein graft (SVG) with therapeutic ICA occlusion were evaluated. Clinical and radiological characteristics were compared in patients with and without the graft occlusion by the logrank test. Graft diameters measured preoperatively, postoperatively, at 6 months, and at 1 year were compared by paired t-test.

RESULTS: During a follow-up period (median 26.2 months), graft occlusions were seen in 4 patients (5.3%), and these were the SVGs. Only SVG was related to graft occlusion (P<.001). There was a significant increase with time in RAG diameters (preoperative, 3.1 ± 0.41 mm; postoperative, 3.6 ± 0.65 mm; 6 months, 4.3 ± 1.0 mm; 1 year, 4.4 ± 1.0 mm), while there were no significant diameter changes in SVGs.

CONCLUSION: The present study showed that the SVG was related to the graft occlusion and RAGs gradually enlarged. Unless Allen test is negative, RAG may be better to be used as a graft in EC-IC HFB if therapeutic ICA occlusion is needed.

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The anterior temporal artery: an underutilized but robust donor for revascularization of the distal middle cerebral artery

J Neurosurg 127:740–747, 2017

The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA).

METHODS The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed.

RESULTS From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses.

CONCLUSIONS The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.

 

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Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques

Operative Neurosurgery 13:552–559, 2017

Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown.

OBJECTIVE: To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques.

METHODS: The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume <70 mL with a ratio of perfusion/diffusion lesion volume ≥1.2, and a regional cerebral blood volume ratio >0.85. FromJanuary 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group.

RESULTS: The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes (P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor.

CONCLUSION: STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke.Advanced MRI techniques are helpful for selecting patients and for decision making.

 

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Accuracy of 320-detector row nonsubtracted and subtracted volume CT angiography in evaluating small cerebral aneurysms

J Neurosurg 127:725–731, 2017

The study aimed to assess the diagnostic accuracy of 320-detector row nonsubtracted and subtracted volume CT angiography (VCTA) in detecting small cerebral aneurysms (< 3 mm) compared with 3D digital subtraction angiography (3D DSA).

METHODS Six hundred sixty-two patients underwent 320-detector row VCTA and 3D DSA for suspected cerebral aneurysms. Five neuroradiologists independently reviewed VCTA and 3D DSA images. The 3D DSA was considered the reference standard, and the sensitivity, specificity, and accuracy of nonsubtracted and subtracted VCTA in depicting small aneurysms were analyzed. A p value < 0.05 was considered a significant difference.

RESULTS According to 3D DSA images, 98 small cerebral aneurysms were identified in 90 of 662 patients. Nonsubtracted VCTA depicted 90 small aneurysms. Ten small aneurysms were missed, and 2 small aneurysms were misdiagnosed. The missed small aneurysms were located almost in the internal carotid artery, near bone tissue. The sensitivity, specificity, and accuracy of nonsubtracted VCTA in depicting small aneurysms were 89.8%, 99.2%, and 96.5%, respectively, on a per-aneurysm basis. Subtracted VCTA depicted 97 small aneurysms. Three small aneurysms were missed, and 2 small aneurysms were misdiagnosed. The sensitivity, specificity, and accuracy of subtracted VCTA in depicting small aneurysms were 96.9%, 99.2%, and 98.6%, respectively, on a per-aneurysm basis. There was no difference in accuracy between subtracted VCTA and 3D DSA (p = 1.000). However, nonsubtracted VCTA had significantly less sensitivity than 3D DSA and subtracted VCTA (p = 0.039 and 0.016, respectively).

CONCLUSIONS Subtracted 320-detector row VCTA is sensitive enough to replace 3D DSA in the diagnosis of small cerebral aneurysms (< 3 mm). The accuracy rate of nonsubtracted VCTA was lower than that of subtracted VCTA and 3D DSA, especially in the assessment of small internal carotid artery aneurysms adjacent to the skull base.

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The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom

J Neurosurg 127:732–739, 2017

Symptomatic chronic subdural hematoma (CSDH) will become an increasingly common presentation in neurosurgical practice as the population ages, but quality evidence is still lacking to guide the optimal management for these patients. The British Neurosurgical Trainee Research Collaborative (BNTRC) was established by neurosurgical trainees in 2012 to improve research by combining the efforts of trainees in each of the United Kingdom (UK) and Ireland’s neurosurgical units (NSUs). The authors present the first study by the BNTRC that describes current management and outcomes for patients with CSDH throughout the UK and Ireland. This provides a resource both for current clinical practice and future clinical research on CSDH.

METHODS Data on management and outcomes for patients with CSDH referred to UK and Ireland NSUs were collected prospectively over an 8-month period and audited against criteria predefined from the literature: NSU mortality < 5%, NSU morbidity < 10%, symptomatic recurrence within 60 days requiring repeat surgery < 20%, and unfavorable functional status (modified Rankin Scale score of 4–6) at NSU discharge < 30%.

RESULTS: Data from 1205 patients in 26 NSUs were collected. Bur-hole craniostomy was the most common procedure (89%), and symptomatic recurrence requiring repeat surgery within 60 days was observed in 9% of patients. Criteria on mortality (2%), rate of recurrence (9%), and unfavorable functional outcome (22%) were met, but morbidity was greater than expected (14%). Multivariate analysis demonstrated that failure to insert a drain intraoperatively independently predicted recurrence and unfavorable functional outcome (p = 0.011 and p = 0.048, respectively). Increasing patient age (p < 0.00001), postoperative bed rest (p = 0.019), and use of a single bur hole (p = 0.020) independently predicted unfavorable functional outcomes, but prescription of high-flow oxygen or preoperative use of antiplatelet medications did not.

CONCLUSIONS: This is the largest prospective CSDH study and helps establish national standards. It has confirmed in a real-world setting the effectiveness of placing a subdural drain. This study identified a number of modifiable prognostic factors but questions the necessity of some common aspects of CSDH management, such as enforced postoperative bed rest. Future studies should seek to establish how practitioners can optimize perioperative care of patients with CSDH to reduce morbidity as well as minimize CSDH recurrence. The BNTRC is unique worldwide, conducting multicenter trainee-led research and audits. This study demonstrates that collaborative research networks are powerful tools to interrogate clinical research questions.

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Impact of Timing of Intervention Among 397 Consecutively Treated Brainstem Cavernous Malformations

Neurosurgery 81:620–626, 2017

Surgical resection of brainstem cavernous malformations (BSCMs) is challenging, and patient selection and timing of intervention remain controversial.

OBJECTIVE: To evaluate the impact of surgical timing and predictors of neurological outcome after surgical resection of BSCMs.

METHODS: Consecutive adult patients (≥18 years) with BSCMs undergoing surgical resection between 1985 and 2014 by the senior author (RFS)were retrospectively reviewed. Patient demographics, lesion characteristics, imaging results, surgical approach, and perioperative and long-term neurological morbidity were analyzed.

RESULTS: Data were analyzed for a total of 397 adult patients (160, 40% male).On univariate analysis, a greater proportion of patients treated within 6 weeks of hemorrhage had an improved Glasgow Outcome Scale score (P = .06). On logistic regression analysis, patients treated within 6weeks of hemorrhage experienced improved clinical outcomes (odds ratio = 1.73; 95% confidence interval = 1.06-2.83; P = .03).

CONCLUSIONS: Although BSCM surgery is associated with significant perioperative morbidity and mortality, favorable long-term hemorrhage rates and symptom resolution can be achieved in a carefully selected group of patients. Overall, patients treated acutely, within 6 weeks, benefited the most from surgical intervention.

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Stereotactic radiosurgery for cerebellar arteriovenous malformations: an international multicenter study

J Neurosurg 127:512–521, 2017

Cerebellar arteriovenous malformations (AVMs) represent the majority of infratentorial AVMs and frequently have a hemorrhagic presentation. In this multicenter study, the authors review outcomes of cerebellar AVMs after stereotactic radiosurgery (SRS).

METHODS: Eight medical centers contributed data from 162 patients with cerebellar AVMs managed with SRS. Of these patients, 65% presented with hemorrhage. The median maximal nidus diameter was 2 cm. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent radiation-induced complications (RICs). Patients were followed clinically and radiographically, with a median follow-up of 60 months (range 7–325 months).

RESULTS: The overall actuarial rates of obliteration at 3, 5, 7, and 10 years were 38.3%, 74.2%, 81.4%, and 86.1%, respectively, after single-session SRS. Obliteration and a favorable outcome were more likely to be achieved in patients treated with a margin dose greater than 18 Gy (p < 0.001 for both), demonstrating significantly better rates (83.3% and 79%, respectively). The rate of latency preobliteration hemorrhage was 0.85%/year. Symptomatic post-SRS RICs developed in 4.5% of patients (n = 7). Predictors of a favorable outcome were a smaller nidus (p = 0.0001), no pre-SRS embolization (p = 0.003), no prior hemorrhage (p = 0.0001), a higher margin dose (p = 0.0001), and a higher maximal dose (p = 0.009). The Spetzler-Martin grade was not found to be predictive of outcome. The Virginia Radiosurgery AVM Scale score (p = 0.0001) and the Radiosurgery-Based AVM Scale score (p = 0.0001) were predictive of a favorable outcome.

CONCLUSIONS: SRS results in successful obliteration and a favorable outcome in the majority of patients with cerebellar AVMs. Most patients will require a nidus dose of higher than 18 Gy to achieve these goals. Radiosurgical and not microsurgical scales were predictive of clinical outcome after SRS.

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Clinical course of untreated thalamic cavernous malformations: hemorrhage risk and neurological outcomes

J Neurosurg 127:480–491, 2017

The natural history of cerebral cavernous malformations (CMs) has been widely studied, but the clinical course of untreated thalamic CMs is largely unknown. Hemorrhage of these lesions can be devastating. The authors undertook this study to obtain a prospective hemorrhage rate and provide a better understanding of the prognosis of untreated thalamic CMs.

METHODS This longitudinal cohort study included patients with thalamic CMs who were diagnosed between 2000 and 2015. Clinical data were recorded, radiological studies were extensively reviewed, and follow-up evaluations were performed.

RESULTS A total of 121 patients were included in the study (56.2% female), with a mean follow-up duration of 3.6 years. The overall annual hemorrhage rate (subsequent to the initial presentation) was calculated to be 9.7% based on the occurrence of 42 hemorrhages over 433.1 patient-years. This rate was highest in patients (n = 87) who initially presented with hemorrhage and focal neurological deficits (FNDs) (14.1%) (c2 = 15.358, p < 0.001), followed by patients (n = 19) with hemorrhage but without FND (4.5%) and patients (n = 15) without hemorrhage regardless of symptoms (1.2%). The initial patient presentations of hemorrhage with FND (hazard ratio [HR] 2.767, 95% CI 1.336–5.731, p = 0.006) and associated developmental venous anomaly (DVA) (HR 2.510, 95% CI 1.275–4.942, p = 0.008) were identified as independent hemorrhage risk factors. The annual hemorrhage rate was significantly higher in patients with hemorrhagic presentation at diagnosis (11.7%, p = 0.004) or DVA (15.7%, p = 0.002). Compared with the modified Rankin Scale (mRS) score at diagnosis (mean 2.2), the final mRS score (mean 2.0) was improved in 37 patients (30.6%), stable in 59 patients (48.8%), and worse in 25 patients (20.7%). Lesion size (odds ratio [OR] per 0.1 cm increase 3.410, 95% CI 1.272–9.146, p = 0.015) and mRS score at diagnosis (OR per 1 point increase 3.548, 95% CI 1.815–6.937, p < 0.001) were independent adverse risk factors for poor neurological outcome (mRS score ≥ 2). Patients experiencing hemorrhage after the initial ictus (OR per 1 ictus increase 6.923, 95% CI 3.023–15.855, p < 0.001) had a greater chance of worsened neurological status.

CONCLUSIONS This study verified the adverse predictors for hemorrhage and functional outcomes of thalamic CMs and demonstrated an overall annual symptomatic hemorrhage rate of 9.7% after the initial presentation. These findings and the mode of initial presentation are useful for clinicians and patients when selecting an appropriate treatment, although the tertiary referral bias of the series should be taken into account.

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Which Cerebral Cavernous Malformations are Most Difficult to Dissect From Surrounding Eloquent Brain Tissue?

Neurosurgery 81:498–503, 2017

Cerebral cavernous malformations (CCM) may lead to repetitive intracerebral hemorrhage. In selected cases, a surgical resection is indicated.

OBJECTIVE: To identify magnetic resonance imaging (MRI) features of CCM that correlate with the difficulty of dissection and postoperative outcome.

METHODS: This study prospectively analyzed pre- and postoperative MRI features, intraoperative findings (surgical questionnaire), and postoperative outcome of 41 patients with eloquent CCM. Based on the results of the surgeon’s questionnaire and postoperative MRI findings, all surgical procedureswere dichotomized in a “difficult”(groupA) or “not difficult” (group B) lesion dissection. Based on the correlation of preoperative MRI features with groups A and B, a 3-tiered classification was established and tested for sensitivity and specificity.

RESULTS: In 22 patients, dissection of the lesion was rated difficult. This was significantly correlated with amount of postoperative diffusion restriction on MRI (P=.001) and postoperative outcome(P=.05). Various preoperative MRI featureswere tested for correlation and combined in a 3-tiered classification. Receiver operating characteristics revealed excellent and good results for predicting difficulty of dissection for the different classification types.

CONCLUSION: We provide a meticulous analysis and new classification of preoperative MRI features that seem to be involved in the microsurgical resection of CCM.

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Early retreatment after surgical clipping of ruptured intracranial aneurysms

Acta Neurochir (2017) 159:1627–1632

Although a rerupture after surgical clipping of ruptured intracranial aneurysms is rare, it is associated with high morbidity and mortality. The causes for retreatment and rupture after surgical clipping are not clearly defined.

Methods From a prospectively maintained database of 244 patients who had undergone surgical clipping of ruptured intracranial aneurysms, we selected patients who experienced retreatment or rerupture within 30 days after surgical clipping. Aneurysm occlusions were examined by microvascular Doppler ultrasonography and indocyanine green video-angiography. Indications for retreatment included rerupture and partial occlusion. We analyzed the characteristics and causes of early retreatment.

Results Six patients (2.5%, 95% CI 0.9 to 5.3%) were retreated within 30 days after surgical clipping, including two patients (0.8%, 95% CI 0.1 to 2.9%) who experienced a rerupture. The retreated aneurysms were found in the anterior communicating artery (AcomA) (n = 5) and basilar artery (n = 1). Retreatment of the AcomA (7.5%) was performed significantly more frequently than that of other arteries (0.56%) (p < 0.01). A laterally projected AcomA aneurysm (17.4%) was more frequently retreated than were other aneurysm types (2.3%). Cases of laterally projecting AcomA aneurysms tended to result from an incomplete clip placed using a pterional approach from the opposite side of the aneurysm projection.

Conclusions Despite developments, the rates of retreatment and rerupture after surgical clipping remain similar to those reported previously. Retreatment of the AcomA was significantly more frequent than was retreatment of other arteries. Patients underwent retreatment more frequently when they were originally treated for lateral type aneurysms using a pterional approach from the opposite side of the aneurysm projection. The treatment method and evaluation modalities should be considered carefully for AcomA aneurysms in particular.

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Endoscopic endonasal transclival resection of a ventral pontine cavernous malformation

J Neurosurg 127:553–558, 2017

Brainstem cavernous malformations are challenging due to the critical anatomy and potential surgical risks. Anterolateral, lateral, and dorsal surgical approaches provide limited ventral exposure of the brainstem.

The authors present a case of a midline ventral pontine cavernous malformation resected through an endoscopic endonasal transclival approach based on minimal brainstem transection, negligible cranial nerve manipulation, and a straightforward trajectory.

Technical and reconstruction technique advances in endoscopic endonasal skull base surgery provide a direct, safe, and effective corridor to the brainstem.

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Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization

J Neurosurg 127:463–479, 2017

Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options.

METHODS Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm.

RESULTS Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery–MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up.

CONCLUSIONS The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.

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Intracranial Aneurysm Parameters for Predicting a Future Subarachnoid Hemorrhage

Neurosurgery 81:432–440, 2017

Retrospective studies have suggested that aneurysm morphology is a risk factor for subarachnoid hemorrhage (SAH).

OBJECTIVE: To investigate whether various morphological indices of unruptured intracranial aneurysms (UIAs) predict a future rupture.

METHODS: A total of 142 patients with UIAs diagnosed between 1956 and 1978 were followed prospectively until SAH, death, or the last contact. Morphological UIA indices from standard angiographic projections weremeasured at baseline and adjusted inmultivariable Cox proportional hazards regression analyses for established risk factors for SAH.

RESULTS: During a follow-up of 3064 person-years, 34 patients suffered froman aneurysm rupture. In multivariable analyses, aneurysm volume, volume-to-ostium area ratio, and the bottleneck factor separately as continuous variables predicted aneurysm rupture. All the morphological indices were higher (P < .01) after the rupture than before. In final multivariable analyses, current smoking (adjusted hazard ratio 2.50, 95% CI 1.03-6.10, P = .044), location in the anterior communicating artery (4.28, 1.38-13.28, P=.012), age (inversely; 0.95 per year, 0.91-1.00, P = .043), and UIA diameter ≥7 mm at baseline (2.68, 1.16-6.21, P = .021) were independent risk factors for a future rupture. Aneurysm growth during the followup was associated with smoking (P < .05) and SAH (P < .001), but not with the aneurysm indices.

CONCLUSION: Of the morphological indices, UIA volume seems to predict a future rupture. However, as volume correlates with the maximum diameter of the aneurysm, it seems to add little to the predictive value of the maximum diameter. Retrospective studies using indices that are measured after rupture are of little value in risk prediction.

 

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Risk Factors to Predict Neurologic Complications After Endovascular Treatment of Unruptured Paraclinoid Aneurysms

WORLD NEUROSURGERY 104: 89-94, AUGUST 2017

Unruptured paraclinoid aneurysms are often asymptomatic, and endovascular coiling is the main treatment. However, endovascular treatment of these lesions still leads to neurologic complications. We aimed to identify predictors of neurologic complications in these lesions.

METHODS: We retrospectively analyzed patients with unruptured paraclinoid aneurysms who were treated with endovascular coiling between January 2014 and December 2015. A neurologic complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. Univariate and mulitivariate logistic regression analyses were performed to assess the risk factors of neurologic complications.

RESULTS: Of the 443 unruptured paraclinoid aneurysms that were included in this study, the incidence of neurologic complications was 5.2%. Neurologic complications were highly correlated with hypertension (odds ratio [OR], 3.147; 95% confidence interval [CI], 1.217e8.138; P [ 0.018), cerebral ischemic comorbidities (OR, 3.396; 95% CI, 1.378e 8.374; P [ 0.008), and aneurysm size (OR, 7.714; 95% CI, 1.784e31.635; P < 0.001), and irregular shape (OR, 3.157; 95% CI, 1.239e8.043; P [ 0.016) in the univariate analysis. Cerebral ischemic comorbidities (OR, 2.837, 95% CI, 1.070e 7.523; P [ 0.036) and aneurysm size as dichotomous variables (OR, 7.557; 95% CI, 2.975e19.198; P < 0.001) were strongly correlated with neurologic complications in the final adjusted multivariate logistic analysis.

CONCLUSIONS: Unruptured paraclinoid aneurysms after endovascular treatments had 5.2% of neurologic complications. Cerebral ischemic comorbidities and aneurysm size were predictors of neurologic complications.

 

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Effect of statin treatment on vasospasm-related morbidity and functional outcome in patients with aneurysmal subarachnoid hemorrhage

J Neurosurg 127:291–301, 2017

The efficacy of statin therapy in treating aneurysmal subarachnoid hemorrhage (SAH) remains controversial. In this meta-analysis, the authors investigated whether statin treatment significantly reduced the incidence of cerebral vasospasm and delayed neurological deficits, promoting a better outcome after aneurysmal SAH.

METHODS: A literature search of the PubMed, Ovid, and Cochrane Library databases was performed for randomized controlled trials (RCTs) and prospective cohort studies investigating the effect of statin treatment. The end points of cerebral vasospasm, delayed ischemic neurological deficit (DIND), delayed cerebral infarction, mortality, and favorable outcome were statistically analyzed.

RESULTS Six RCTs and 2 prospective cohort studies met the eligibility criteria, and a total of 1461 patients were included. The meta-analysis demonstrated a significant decrease in the incidence of cerebral vasospasm (relative risk [RR] 0.76, 95% confidence interval [CI] 0.61–0.96) in patients treated with statins after aneurysmal SAH. However, no significant benefit was observed for DIND (RR 0.88, 95% CI 0.70–1.12), delayed cerebral infarction (RR 0.66, 95% CI 0.33–1.31), mortality (RR 0.69, 95% CI 0.39–1.24) or favorable outcome, according to assessment by the modified Rankin Scale or Glasgow Outcome Scale (RR 0.99, 95% CI 0.92–1.17).

CONCLUSIONS Treatment with statins significantly decreased the occurrence of vasospasm after aneurysmal SAH. The incidence of DIND, delayed cerebral infarction, and mortality were not affected by statin treatment. Future research should focus on DIND and how statins influence DIND.

 

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Critical review of brain AVMsurgery, surgical results and natural history in 2017

Acta Neurochir (2017) 159:1457–1478

An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention.

Methods A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks.

Results In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVMwho have either a DVD or eloquent location (but not both), the 8- year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%.

Conclusion Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

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Endoscope-assisted transsphenoidal puncture of the cavernous sinus for embolization of carotid-cavernous fistula

J Neurosurg 127:327–331, 2017

Endovascular embolization is the treatment of choice for carotid-cavernous fistulas (CCFs), but failure to catheterize the cavernous sinus may occur as a result of vessel tortuosity, hypoplasia, or stenosis. In addition to conventional transvenous or transarterial routes, alternative approaches should be considered. The authors present a case in which a straightforward route to the CCF was accessed via transsphenoidal puncture of the cavernous sinus in a neurosurgical hybrid operating suite.

This 82-year-old man presented with severe chemosis and proptosis of the right eye. Digital subtraction angiography revealed a Type B CCF with a feeding artery arising from the meningohypophyseal trunk of the right cavernous segment of the internal carotid artery. The CCF drained through a thrombosed right superior ophthalmic vein that ended deep in the orbit; there were no patent sinuses or venous plexuses connecting to the CCF. An endoscope-assisted transsphenoidal puncture created direct access to the nidus for embolization. Embolic agents were deployed through the puncture needle to achieve complete obliteration.

Endoscope-assisted transsphenoidal puncture of the cavernous sinus is a feasible alternative to treat difficult-to-access CCFs in a neurosurgical hybrid operating suite.

 

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