Category: Vascular

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Randomized, double-blind, placebo-controlled, pilot trial of high-dose methylprednisolone in aneurysmal subarachnoid hemorrhage

J Neurosurg 112:681–688, 2010. DOI: 10.3171/2009.4.JNS081377

The object of this study was to determine the efficacy of methylprednisolone in reducing symptomatic vasospasm and poor outcomes after subarachnoid hemorrhage (SAH).

Methods. Ninety-five patients with proven SAH were recruited into a double-blind, placebo-controlled, random- ized trial. Starting within 6 hours after angiographic diagnosis of aneurysm rupture, placebo or methylprednisolone, 16 mg/kg, was administered intravenously every day for 3 days to 46 and 49 patients, respectively. Deterioration, defined as development of a focal sign or decrease of more than 1 point on the Glasgow Coma Scale for more than 6 hours, was investigated by using clinical criteria and transcranial Doppler ultrasonography, cerebral angiography, or CT when appropriate. The end points were incidence of symptomatic vasospasm (delayed ischemic neurological deficits associated with angiographic arterial narrowing or accelerated flow on Doppler ultrasonography, or both) and outcome 1 year after entry into the study according to a simplified Rankin scale (Functional Outcome Scale [FOS]) in living patients and the Glasgow Outcome Scale in all patients included.

Results. All episodes of deterioration and all living patients with a 1-year outcome were assessed by a review committee. In patients treated with methylprednisolone, the incidence of symptomatic vasospasm was 26.5% com- pared with 26.0% in those given placebo. Poor outcomes according to FOS were significantly reduced in the Meth- ylprednisolone Group at 1 year of follow-up; the risk difference was 19.3% (95% CI 0.5–37.9%). The outcome was poor in 15% (6/40) of patients in the Methylprednisolone Group versus 34% (13/38) in the Placebo Group.

Conclusions. A safe and simple treatment with methylprednisolone did not reduce the incidence of symptomatic vasospasm but improved ability and functional outcome at 1 year after SAH.

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Monitoring intracranial pressure in patients with malignant middle cerebral artery infarction: is it useful?

J Neurosurg 112:648–657, 2010. DOI: 10.3171/2009.7.JNS081677

Intracranial pressure (ICP) monitoring is increasingly used in the treatment of patients with malignant middle cerebral artery (MCA) infarction. However, neurological deterioration may exist independent from intracranial hypertension. This study aimed to present the findings of continuous ICP monitoring in a cohort of patients with malignant MCA infarction and to correlate these findings with clinical and radiological features.

Methods. The authors studied a prospective cohort of 25 patients with malignant MCA infarction consecutively admitted to the neurotrauma intensive care unit of the Vall d’Hebron University Hospital between March 2002 and September 2006. The patients were treated using a combined protocol of initial moderate hypothermia and hemi-craniectomy. The latter was performed when patients showed a midline shift (MLS) ≥ 5 mm or ICP > 20 mm Hg. Six patients had an MLS ≥ 5 mm on the first CT scan and underwent surgery without prior ICP monitoring. This study focuses on the subgroup of 19 patients who underwent intraparenchymatous ICP monitoring before surgery.

Results. Intracranial pressure readings were evaluated and correlated with pupillary abnormalities, MLS, and ischemic tissue volume. In 12 of the 19 patients, ICP values were always ≤ 20 mm Hg, despite a mean (± SD) MLS of 6.7 ± 2 mm and a mean ischemic tissue volume of 241.3 ± 83 cm3. In 2 patients with anisocoria, ICP values were also normal.

Conclusions. In patients with a malignant MCA infarction, pupillary abnormalities and severe brainstem compression may be present despite normal ICP values. Therefore, continuous ICP monitoring cannot substitute for close clinical and radiological follow-up in the management of these patients.

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Outcome correlates with blood distribution in subarachnoid hemorrhage of unknown origin

Acta Neurochir (2010) 152:417–42.DOI10.1007/s00701-009-0525-9

Between 15 and 30 % of patients with subarachnoid hemorrhage (SAH) have no bleeding source and usually have a benign clinical course and outcome. The objectives of this study were to classify the pattern of blood distribution on initial computed tomography (CT) and to correlate it with clinical outcome in aneurysmal (ASAH) and SAH of unknown origin (SAHuO).

Methods We reviewed 112 CTs of SAHuO and 104 CTs of ASAH patients. Blood distribution was classified according to a new grading system (type 0–4) and correlated to Hunt and Hess (H&H) grade and modified Rankin scores (MRS) at short- and long-term follow-up.

Results Fifty percent of 112 SAHuO patients were classified as type 0 (no visible blood on CT) or 1 (blood restricted to prepontine cisterns). Most ASAH patients presented with bleeding into the lateral Sylvian fissure (66%; type 3) or with intracerebral hemorrhage (27%; type 4) whereas types 0 and 1 were not observed. SAHuO patients were in better clinical condition on admission than ASAH patients (p<0.0001). H&H grades of SAHuO patients correlated with the amount of subarachnoid blood according to the new classification (p=0.004). Short-term outcome was obtained from 100% and long-term outcome from 95% patients (follow-up 29±31 months). Short- and long-term MRS correlated with blood distribution in SAHuO patients (p=0.012) and was significantly better than in ASAH patients (p<0.0001). No correlation was observed between blood distribution, H&H grade, and short- and long-term outcome in aneurysmal patients.

Conclusions In SAH of unknown origin, a new classification allows to predict outcome based on the extent of blood on CT.

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How Safe Is Arteriovenous Malformation Surgery? A Prospective, Observational Study of Surgery As First-Line Treatment for Brain Arteriovenous Malformations

DOI: 10.1227/01.NEU.0000365518.47684.98

OBJECTIVES: Existing studies reporting the risk of surgery for brain arteriovenous malformations (AVMs) are often biased by the exclusion of patients not offered surgery. In this study, we examine the risk of surgery, including cases excluded from surgery because of the high surgical risk.
METHODS: Data were collected on 640 consecutively enrolled AVMs in a database that included all patients not considered for surgery.
RESULTS: Patients with Spetzler-Martin grade 1 to 2 AVMs (n = 296) were treated with a surgical risk of 0.7% (95% confidence interval [CI], 0%-3%); patients with Spetzler-Martin grade 3 to 4 AVMs in noneloquent cortex (n = 65) were treated with a surgical risk of 17% (95% CI, 10%-28%). Patients with Spetzler-Martin grade 3 to 5 AVMs in eloquent cortex (n = 168) were treated with a surgical risk of 21% (95% CI, 15%-28%). However, because 14% of patients in this series with similar AVMs were refused surgery because of perceived surgical risk, these results are not generalizable to the population of patients with similar AVMs.
CONCLUSION: The results of this series suggest that it is reasonable to offer surgery as a preferred treatment option for Spetzler-Martin grade 1 to 2 AVMs. This study also reinforces the predictive value of the Spetzler-Martin grading system, with some caveats.

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Cognitive Functioning and Health-Related Quality of Life 1 Year After Aneurysmal Subarachnoid Hemorrhage in Preoperative Comatose Patients (Hunt and Hess Grade V Patients)

DOI: 10.1227/01.NEU.0000365364.87303.AC

OBJECTIVE: The objective of this study was to determine cognitive functioning and health related quality of life one year after aneurysmal subarachnoid hemorrhage in preoperative comatose patients.

METHODS: Patients were investigated for one year using a comprehensive neuropsychological test battery and two HRQOL questionnaires.

RESULTS: Thirty-five of 70 patients survived the bleed, and 26 underwent neuropsychological testing. Two distinct patient groups emerged; one (n = 14) with good cognitive function, and the other (n = 12) with poor cognitive and motor function. Patients performing poorly were older (p = 0.04), had fewer years of education, (p = 0.005) larger preoperative ventricular scores, and were more often shunted (p = 0.02). There were also differences between the two groups in the Glasgow Outcome Scale (p = 0.001), modified Rankin Scale (p = 0.001), and employment status. HRQOL was more reduced in patients with poor cognitive function.

CONCLUSION: A high fraction of survivors among preoperative comatose aneurysmal SAH patients (Hunt and Hess grade V patients) recover to a good physical and cognitive function.

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Preliminary Personal Experiences With the Application of Near-Infrared Indocyanine Green Videoangiography in Extracranial Vertebral Artery Surgery

INTRODUCTION:We evaluated the feasibility, usefulness, and limitations of near-infrared indocyanine green (ICG) videoangiography during procedures involving the extracranial vertebral artery (VA).

METHODS: Nine patients (2 women, 7 men; mean age, 55 years) were evaluated at 2 neurosurgical centers. Near-infrared ICG videoangiography was applied during transposition and rerouting of the first segment of VA (V1; n = 6) and during resection of neurinomas near the second (V2; n = 1) and third (V3; n = 2) segments of VA.

RESULTS: Early after ICG injection, V1 fluoresced homogenously. The fluorescence of V2 and V3 varied. Without extrinsic compression, these segments appeared as noncontiguous hot spots because the VA runs freely in a periosteal sheath surrounded by a venous plexus that attenuates the fluorescent light. Hot spots corresponded to areas where the artery neared the surface. With extrinsic compression, VA enhanced homogenously because it was pushed against the periosteal layer. During the late phase, the V1 signal was attenuated, whereas the venous plexus surrounding V2 and V3 enhanced homogeneously, thereby masking the VA itself. Near-infrared ICG videoangiography helped to confirm VA patency during transposition and rerouting but was not helpful during VA exposure because the periosteal sheath must already be exposed to detect the VA or its surrounding plexus. After exposure, videoangiography can help to determine the position of the VA within its periosteal sheath.

CONCLUSION: Videoangiography can be used to provide information about the patency of the VA and its location within the periosteal sheath to prevent injury during resection of tumor adherent to the periosteal sheath.

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Supracerebellar Infratentorial Approach to Cavernous Malformations of the Brainstem: Surgical Variants and Clinical Experience With 45 Patients

Neurosurgery 66:389-399, 2010. DOI: 10.1227/01.NEU.0000363702.67016.5D

OBJECTIVE: The supracerebellar infratentorial (SCIT) approach can be performed at the midline (median variant), lateral to the midline (paramedian variant), or at the level of the angle formed by the transverse and sigmoid sinuses (extreme lateral variant). We analyzed our experience with SCIT approaches for the surgical treatment of cavernous malformations of the brainstem (CMBs).

METHODS: Demographic, clinical, radiologic, and surgical data from 45 patients (20 males and 25 females; mean age, 36.2 years) with CMBs surgically removed through SCIT approaches were reviewed retrospectively. Anatomic information was explored using cadaver head dissection.

RESULTS: Twenty-three lesions were in the midbrain, 3 were at the midbrain and extended to the thalamus, 9 were at the pontomesencephalic junction, and 10 were in the upper pons. All patients presented with hemorrhage. The median variant was used in 13 patients, the paramedian variant in 9, and the extreme lateral variant in 23. Intraoperatively, all CMBs were associated with a developmental venous anomaly. At last follow-up, 88% of the patients were the same or better. After a mean follow-up of 20 months, their mean Glasgow Outcome Scale score was 4.1.

CONCLUSION: SCIT approaches provide excellent exposure to CMBs located at the posterior incisural space, not only in the midline but also in the posterolateral surface of the upper pons and midbrain. Careful preoperative planning and neuronavigational assistance are needed to determine the best angle of attack and trajectory for SCIT approaches. Refined microsurgical techniques are paramount to achieve safe surgical removal of CMBs with good outcomes.

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Intracranial infectious aneurysms: a comprehensive review

Neurosurg Rev (2010) 33:37–46 DOI 10.1007/s10143-009-0233-1

Intracranial infectious aneurysms, or mycotic aneurysms, are rare infectious cerebrovascular lesions which arise through microbial infection of the cerebral arterial wall. Due to the rarity of these lesions, the variability in their clinical presentations, and the lack of population-based epidemiological data, there is no widely accepted management methodology. We undertook a comprehensive literature search using the OVID gateway of the MEDLINE database (1950–2009) using the following keywords (singly and in combination): “infectious,” “mycotic,” “cerebral aneurysm,” and “intracranial aneurysm.” We identified 27 published clinical series describing a total of 287 patients in the English literature that presented demographic and clinical data regarding presentation, treatment, and outcome of patients with mycotic aneurysms. We then synthesized the available data into a combined cohort to more closely estimate the true demographic and clinical characteristics of this disease. We follow by presenting a comprehensive review of mycotic aneurysms, highlighting current treatment paradigms. The literature supports the administration of antibiotics in conjunction with surgical or endovascular intervention depending on the character and location of the aneurysm, as well as the clinical status of the patient. Mycotic aneurysms comprise an important subtype of potentially life-threatening cerebrovascular lesions, and further prospective studies are warranted to define outcome following both conservative and surgical or endovascular treatment.

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Gamma knife radiosurgery for arteriovenous malformations of basal ganglia, thalamus and brainstem—a retrospective study comparing the results with that for AVMs at other intracranial locations

Objective The objective of this retrospective study was to study the outcome in patients with basal ganglia, thalamus and brainstem (central/deep) arteriovenous malformations (AVMs) treated with gamma knife radiosurgery (GKS) and to compare the results with that for AVMs at other intracranial locations.
Methods and results The results of 53 patients with central AVMs and 255 patients with AVMs at other locations treated with GKS at our center between April 1997 and March 2005 with minimum follow-up of 1 year were analyzed.
Central AVMs Forty of these 53 AVMs were Spetzler-Martin grade III, 11 were grade IV, and 2 were grade V. The mean AVM volume was 4.3 cm3 (range 0.1–36.6 cm3). The mean marginal dose given was 23.3 Gy (range 16–25 Gy). The mean follow-up was 28 months (range 12–96 months). Check angiograms were advised at 2 years after GKS and yearly thereafter in the presence of residual AVM till 4 years. Presence of a residual AVM on an angiogram at 4 years after radiosurgery was considered as radiosurgical failure. Complete obliteration of the AVM was documented in 14 (74%) of the 19 patients with complete angiographic follow-up. Significantly lower obliteration rates (37% vs. 100%) were seen in larger AVMs (>3 cm3) and AVMs of higher (IV and V) Spetzler-Martin grades (28% vs. 100%). The 3- and 4-year actuarial rates of nidus obliteration were 68% and 74%, respectively. Eight patients (15%) developed radiation edema with a statistically significantly higher incidence in patients with AVM volume >3 cm3 and in patients with Spetzler-Martin grade IV and V AVMs. Five patients (9.4%) had hemorrhage in the period of latency.
Comparison of results with AVMs at other locations Patients with central AVMs presented at a younger age (mean age 22.7 years vs. 29 years), with a very high proportion (81% vs. 63%) presenting with hemorrhage. Significantly higher incidence of radiation edema (15% vs. 5%) and lower obliteration rates (74% vs. 93%) were seen in patients with central AVMs.
Conclusions GKS is an effective modality of treatment for central AVMs, though relatively lower obliteration rates and higher complication rates are seen compared to AVMs at other locations.
Key words: Basal ganglia – Brainstem – Central arteriovenous malformations – Deep brain arteriovenous malformations – Gamma knife – Thalamus
DOI 10.1007/s00701-009-0335-0

Acta Neurochirugica December 2009.

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Prediction of early secondary complications in patients with spontaneous subarachnoid hemorrhage based on accelerated sympathovagal ratios

Acta Neurochir (2009) 151:1631–1637 DOI 10.1007/s00701-009-0517-9

Purpose The development of secondary complications following spontaneous subarachnoid hemorrhage (SAH) largely depends on sympathetic overexcitation. The roles of vagal activities, however, are poorly defined. Because both components of the autonomic nervous system can be explored in the frequency domain of heart rate variability (HRV), the present study aimed to determine the dynamic evolution of autonomic activities and to identify patients at high risk for complications following hemorrhage. Methods Thirty patients with SAH were enrolled in our study. Those who suffered from symptomatic vasospasm, cerebral infarction, neurogenic pulmonary edema, or early mortality within 1 week of ictus were categorized into the complication group. Spectral analysis of HRV explored three important indices of sympathetic and vagal modu- lations: low-frequency (LF), high-frequency (HF), and LF/HF ratios. Patterns of HRV dynamics within the first 3 days were compared between complication and non complication groups. The group trends, estimated by the slopes of HRV changes, were determined for further univariate and multivariate analysis. Results Our study showed that daily HRV in the complica- tion group exhibited an approximately 2.7-fold increase of sympathovagal ratio (denoted by LF/HF). This resulted from reciprocal changes of sympathoexcitation (LF) and vagal withdrawal (HF). Multivariate analysis revealed that LF/HF slope, an indicator of the trend of sympathovagal change, was an independent variable significantly associat- ed with the development of complications.

Conclusions This study confirmed that during early SAH period, patients with and without complications presented different patterns of sympathovagal changes. LF/HF slope during the first 3 days was a significant predictor of secondary complications after SAH.

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Single-center experience with the Neuroform stent for endovascular treatment of wide-necked intracranial aneurysms

Surgical Neurology 72 (2009) 612–619. DOI:10.1016/j.surneu.2009.03.038

Background: Stent-assisted coiling is an accepted endovascular treatment (EVT) for wide-necked intracranial aneurysms. The Neuroform stent (Target Therapeutics, Fremont, Calif) is a flexible nitinol self-expandable stent that was designed to potentially overcome the limitations of balloon expandable coronary stents in the intracranial circulation. The aim of this study was to reenforce the use of this stent for EVT of wide-necked cerebral aneurysms.

Methods: Between March 2005 and March 2008, 24 patients harboring wide-necked cerebral aneurysms were treated with stent reconstruction of the aneurysm neck. Inclusion criteria restricted the group to adult patients with wide-necked intracranial aneurysms (ruptured and unruptured lesions). Immediate postprocedure angiography studies were performed to determine successful coil occlusion of the aneurysm as well as patency of the parent vessel. We assessed the clinical history, aneurysm dimensions, and technical detail of the procedures, including any difficulties with stent placement and deployment, degree of aneurysm occlusion, and complications. Clinical outcome was assessed with the Glasgow Outcome Scale (GOS).

Results: The stent was easily navigated and precisely positioned in 24 of 26 cases. However, technical difficulties occurred in 9 patients, including difficulties in crossing the stents interstice in 6 cases, inadvertent stent delivery (n = 1), and incapacity of stent delivery (n = 1) and incapacity of crossing the neck (n = 1). These latter 2 cases were classified as failures of the stent-assisted technique. A single procedural complication occurred, involving transient nonocclusive intrastent thrombus formation, which was treated uneventfully with abciximab. Seventeen patients experienced excellent clinical outcomes (GOS 5), with good outcomes (GOS 4) in 5 patients and a poor outcome (GOS 3) in 2 patients. There were no treatment-related deaths or neurologic complications (mean clinical follow-up, 12 months). Angiographic results consisted of 17 complete occlusions, 4 neck remnants, and 3 incomplete occlusions.

Conclusions: The Neuroform stent is very useful for EVT of wide-necked intracranial aneurysms because it is easy to navigate and to deploy accurately. In most cases, the stent can be deployed precisely, even in very tortuous carotid siphons. Although in some cases delivery and deployment was challenging, clinically significant complications were not observed.

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Pre-mesencephalic subarachnoid hemorrhage: rupture of tiny aneurysms of the basilar artery perforator

Acta Neurochir (2009) 151:1639–1646. DOI 10.1007/s00701-009-0416-0

Subarachnoid hemorrhage (SAH) around the midbrain without evidence of aneurysm, a so-called perimesencephalic SAH, has been considered a typical nonaneurysmal SAH. Recently, we have encountered several patients with SAHs that could have been classified as having perimesencephalic SAH, but a common cause of the bleeding was demonstrated. In this article, we describe clinical and radiologic characteristics of these patients.

Methods: Clinical and radiologic data from patients with spontaneous SAH (total number 339) who were treated at Seoul National University Bundang Hospital between May 2003 and December 2007 were reviewed.

Results: Of the 13 patients that could be classified as having perimesencephalic SAH, three had common radiologic features that were distinct from others. On computed tomography, the main hemorrhage (hematoma) was found localized in front of the midbrain (interpeduncular and/or peduncular cistern). Angiographically, the cause of the bleeding was not seen on conventional views and rotational angiograms. In three-dimensional reconstructed angiographic images, very small-sized (tiny) aneurysmal lesions were visible at the origin of mesencephalic perforators from the basilar artery. All the aneurysms were positioned at the exact site corresponding to the pre-mesencephalic clots. Follow-up angiography was performed on the three patients and all showed complete disappearance of the lesions at 1 month, 15 months, and 16 months follow-up, respectively.

Conclusions: Based on our experience, we suggest a subtype of spontaneous SAH that has unique hemorrhage localization (pre-mesencephalic cistern), specific cause (tiny aneurysms at the origin of the mesencephalic perforator), and a common benign clinical course.

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The effect of coiling vs clipping of ruptured and unruptured cerebral aneurysms on length of stay, hospital cost, hospital reimbursement, and surgeon reimbursement at the University of Florida

Neurosurgery 64:614–621, 2009 DOI: 10.1227/01.NEU.0000340784.75352.A4

There are few studies comparing the economic costs and reimbursements for aneurysm clipping versus coiling, and none are from the United States. Our hypothesis predicted that coiling would result in shorter lengths of hospitalization than clipping in patients with unruptured aneurysms and would therefore result in lower hospital charges. However, because of the severity of subarachnoid hemorrhage, there would be no difference in length of hospitalization or hospital charges in patients with ruptured aneurysms.

Methods: We compared aneurysm coiling with aneurysm clipping in patients with unruptured and ruptured aneurysms treated at the University of Florida from January 2005 to June 2007 for differences in length of hospitalization, hospital costs, hospital collections, and surgeon collections. Patient demographic and aneurysm characteristic data were obtained from a clinical database. Length of hospitalization, cost, billing, and collection data were obtained from the hospital cost accounting database. Multivariate statistical analyses of length of hospitalization, hospital costs, hospital collections, and surgeon collections were performed using factors including patient age, sex, aneurysm size, aneurysm location, aneurysm treatment, presence of subarachnoid hemorrhage, clinical grade, payor, hospital billing, and surgeon billing.

Results: There were 565 patients with cerebral aneurysms treated either surgically (306 patients, 54%) or endovascularly (259 patients, 46%). In patients without subarachnoid hemorrhage (unruptured aneurysms) (n=367), surgery, compared with endovascular treatment, was associated with longer hospitalization (P<0.001), but lower hospital costs (P<0.001), higher surgeon collections (P<0.003), and similar hospital collections. In patients with subarachnoid hemorrhage (ruptured aneurysms) (n=198), surgery was associated with lower hospital costs (P<0.011), but similar length of stay, surgeon collections, and hospital collections. Larger aneurysm size was significantly associated with longer hospitalization in the patients with unruptured aneurysms (P<0.001) and higher hospital costs for both patients with unruptured (P<0.001) and ruptured (P<0.015) aneurysms. The payor was significantly associated with hospital costs in patients with ruptured aneurysms (P<0.034) and length of stay (unruptured aneurysms, P<0.001; ruptured aneurysms, P<0.001), hospital collections (unruptured aneurysms, P<0.001; ruptured aneurysms, P<0.001), and surgeon collections (unruptured aneurysms, P<0.001; ruptured aneurysms, P<0.001) in both patients with unruptured and ruptured aneurysms. A worse clinical grade was significantly associated with higher hospital costs (P<0.001).

Conclusion: Despite a shorter length of hospitalization in patients with unruptured aneurysms, coiling was associated with higher hospital costs in both patients with unruptured and ruptured aneurysms. This is likely attributable to the higher device cost of coils than clips. The advantages of coiling over clipping would be better realized if the cost of coils could be comparably reduced to that of clips.

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Relationship between intracranial hemodynamics and microdialysis markers of energy metabolism and glutamate-glutamine turnover in patients with subarachnoid hemorrhage

J Neurosurg 111:910–915, 2009.DOI: 10.3171/2008.8.JNS0889

The aim of this study was to explore the relationship between hemodynamics (intracranial and systemic) and brain tissue energy metabolism, and between hemodynamics and glutamate (Glt)-glutamine (Gln) cycle activity.

Methods. Brain interstitial levels of lactate, pyruvate, Glt, and Gln were prospectively monitored in the neurointensive care unit for more than 3600 hours using intracerebral microdialysis in 33 patients with subarachnoid hemorrhage (SAH). Intracranial pressure (ICP), mean arterial blood pressure, and cerebral perfusion pressure (CPP) were recorded using a digitalized system.

Results. Interstitial Gln and pyruvate correlated with CPP (r = 0.25 and 0.24, respectively). Intracranial pressure negatively correlated with Gln (r = −0.29) and the Gln/Glt ratio (r = –0.40). Levels of Gln and pyruvate and the Gln/Glt ratio were higher and levels of Glt and lactate and the lactate/pyruvate ratio were lower during periods of decreased ICP (≤ 10 mm Hg) as compared with values in periods of elevated ICP (> 10 mm Hg). In 3 patients, a poor clinical condition was attributed to high ICP levels (range 15–25 mm Hg). When CSF drainage was increased and the ICP was lowered to 10 mm Hg, there was an instantaneous sharp increase in interstitial Glt and pyruvate in these 3 patients.

Conclusions. Increasing interstitial Gln and pyruvate levels appear to be favorable signs associated with improved CPP and low ICP. The authors suggest that this pattern indicates an energy metabolic situation allowing augmented astrocytic energy metabolism with accelerated Glt uptake and Gln synthesis. Moreover, their data raised the question of whether patients with SAH and moderately elevated ICP (15–20 mm Hg) would benefit from CSF drainage at lower pressure levels than what is usually indicated in current clinical protocols.

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Efficacy of endovascular stenting in dural venous sinus stenosis for the treatment of idiopathic intracranial hypertension

Neurosurg Focus 27 (5):E14, 2009.DOI: 10.3171/2009.9.FOCUS09165

Multiple pathophysiological mechanisms have been proposed for the increased intracranial pressure observed in idiopathic intracranial hypertension (IIH). The condition is well characterized, with intractable headaches, visual obscurations, and papilledema as dominant features, mainly affecting obese women. With the advent of MR venography and increased use of cerebral angiography, there has been recent emphasis on the significant number of patients with IIH found to have associated nonthrombotic dural venous sinus stenosis. This has led to a renewed interest in endovascular stenting as a treatment for IIH. However, the assumption that venous stenosis leads to a high pressure gradient that decreases CSF resorption through arachnoid villi requires further evidence.

In this paper, the authors analyze the published results to date of dural venous sinus stenting in patients with IIH. They also present a case from their institution for illustration.

The pathophysiological mechanism in IIH requires further elucidation, but venous sinus stenosis with subsequent intracranial hypertension appears to be an important mechanism in at least a subgroup of patients with IIH. Among these patients, 78% had complete relief or improvement of their main presenting symptoms after endovascular stenting.

Resolution or improvement in papilledema was seen in 85.1% of patients.

Endovascular stenting should be considered whenever venous sinus stenosis is diagnosed in patients with IIH.

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Management of pediatric brainstem cavernous malformations: experience over 20 years at the Hospital for Sick Children

J Neurosurg Pediatrics 4:040580–400640, 2009.DOI: 10.3171/2009.6.PEDS0923

Because of their location and biological behavior, brainstem cavernous malformations (CMs) pose a formidable clinical challenge to the neurosurgeon. The optimal management of these lesions requires considerable neurosurgical judgment. Accordingly, the authors reviewed their experience with the management of pediatric brain- stem CMs at the Hospital for Sick Children.

Methods. The authors performed a retrospective chart review of pediatric patients who had received diagnoses of a brainstem CM at the Hospital for Sick Children over the past 20 years.

Results. Twenty patients were diagnosed with brainstem CMs. The mean age at diagnosis was 10.1 ± 5.4 years, and the patients included 13 boys and 7 girls. The mean maximal diameter of the CM was 14.3 ± 11.2 mm. The le- sions were evenly distributed on the right and left sides of the brainstem with 4 midbrain, 13 pontine, and 3 medullary lesions. Seven patients underwent surgery for the management of their CMs, with a mean age at presentation of 5.2 years, and a mean CM size of 21.0 mm. Of note from the surgical group, 2 patients had a family history of CMs, 2 lesions were medullary, the CM reached a pial surface in 6 of 7 patients, and 6 of 7 lesions were located on the right side. The mean age at presentation among the 13 patients in the nonsurgical group was 12.7 years, and the mean CM size was 10.6 mm. Seven of these patients had a prior history of radiation for tumor, and only 3 had lesions that reached a pial surface.

Conclusions. The management of brainstem CMs in children is influenced by multiple factors. The majority of patients received conservative management and tended to be asymptomatic with smaller lesions. Patients with larger lesions and direct pial contact, in whom symptoms arose at a younger age were more likely to undergo surgical management. A history of familial CM was also a predictor for receiving surgical treatment. No patients with a prior history of radiation therapy underwent surgery for CMs. The presence of multiple lesions seemed to have no impact on the type of management chosen. Patients who underwent surgery did suffer morbidity related to the procedure, and tended to improve clinically over time. Conservative management was associated with new deficits arising in children, some of which improved with time. Consideration of many clinical and radiological parameters is thus prudent when managing the care of children with brainstem CMs.

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Shunt­dependent hydrocephalus after aneurysmal subarachnoid hemorrhage

J Neurosurg 111:1029–1035, 2009. DOI: 10.3171/2008.9.JNS08881

Chronic shunt­dependent hydrocephalus is a recognized complication of aneurysmal subarachnoid hem­ orrhage. While its incidence and risk factors have been well described, the long­term performance of shunts in this setting has not been not widely reported.

Methods. Using administrative databases, the authors derived a retrospective cohort of patients undergoing treat­ ment of a ruptured aneurysm in Ontario, Canada, between 1995 and 2005. The authors determined the incidence of shunt­dependent hydrocephalus and analyzed putative risk factors. Mortality rates and indicators of morbidity were recorded. Patients were followed up for the occurrence of shunt failure over time.

Results. Of 3120 patients in the cohort, 585 (18.75%) developed shunt-dependent hydrocephalus. On multivari­ ate analysis, age, acute hydrocephalus, ventilation on admission, aneurysms in the posterior circulation and giant aneurysms were all significant predictors of shunt-dependent hydrocephalus. The mortality rate was not increased in patients with chronic hydrocephalus (hazard ratio 1.04, p = 0.63); however, indicators of morbidity were increased in these patients. Of the 585 patients with shunt-dependent hydrocephalus, only 173 (29.6%) underwent a subsequent revision procedure. Ninety-eight percent of these revisions were completed within 6 months. Subsequent revisions occurred more frequently. On multivariate analysis, significant predictors of shunt revision included aneurysm loca­ tion in the posterior circulation and endovascular treatment of the initial ruptured aneurysm.

Conclusions. Shunt-dependent hydrocephalus affects a significant proportion of subarachnoid hemorrhage sur­ vivors, contributing to additional morbidity among these patients. Shunt failures occur less frequently in patients who underwent treatment for a ruptured aneurysm than with other forms of hydrocephalus. Most failures occur within 6 months, suggesting that shunt dependency may be transient in the majority of patients.

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Cerebral venous sinus thrombosis: review of the demographics, pathophysiology, current diagnosis, and treatment

Neurosurg Focus 27 (5):E3, 2009. DOI: 10.3171/2009.8.FOCUS09167

Cerebral venous sinus thrombosis (CVST) is a rare clinicopathological entity. The incidence of CVST in chil- dren and neonates has been reported to be as high as 7 cases per million people, whereas in adults the incidence is 3–4 cases per million. The predisposing factors to this condition are mainly genetic and acquired prothrombotic states and infection. The clinical picture of CVST is nonspecific, highly variable, and can mimic several other clinical conditions. Diagnosis of CVST is established with the implementation of neuroimaging studies, especially MR imaging and venography. Identification and elimination of the underlying cause, anticoagulation, proper management of intracranial hypertension, and anticonvulsant prophylaxis constitute cornerstones of CVST treatment. Newer treatment strategies such as endovascular thrombolysis and decompressive craniectomy have been recently used in the treatment of patients with CVST with variable success rates. Further clinical research must be performed to delineate the exact role of these newer treatments in the management of severe cases of CVST. The recent advances in the diagnosis and treatment of patients with CVST have significantly lowered the associated mortality and morbidity and have improved the outcome of these patients.

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Three-dimensional simulation for aneurysm surgery

Neurosurgery 65:719–726, 2009 DOI: 10.1227/01.NEU.0000354350.88899.07

OBJECTIVE: With improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented.

METHODS:The 3D hollow aneurysm models of 3 retrospective and 8 prospective cases were made with a prototyping technique according to data from 3D computed tomographic angiograms of each patient. Commercially available titanium clips used in our routine surgery were applied, and the internal lumen was observed with an endoscope to confirm the patency of parent vessels. The actual surgery was performed later.

RESULTS: In the 8 prospective cases, the clips were applied during surgery in the same direction and configuration as in the preoperative simulation. Fine adjustments were necessary in each case, and 2 patients needed additional clips to occlude the atherosclerotic aneurysmal wall. With these 3D models, it was easy for neurosurgical trainees to grasp the vascular configuration and the concept of neck occlusion. Practicing surgery with these models also improved their handling of the instruments used during

aneurysm surgery, such as clips and appliers.

CONCLUSION: Using the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.

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Intracranial infectious aneurysms: a comprehensive review

Neurosurg Rev DOI 10.1007/s10143-009-0233-1

Intracranial infectious aneurysms, or mycotic aneurysms, are rare infectious cerebrovascular lesions which arise through microbial infection of the cerebral arterial wall. Due to the rarity of these lesions, the variability in their clinical presentations, and the lack of population-based epidemiological data, there is no widely accepted management methodology. We undertook a comprehensive literature search using the OVID gateway of the MEDLINE database (1950–2009) using the following keywords (singly and in combination): “infectious,” “mycotic,” “cerebral aneurysm,” and “intracranial aneurysm.” We identified 27 published clinical series describing a total of 287 patients in the English literature that presented demographic and clinical data regarding presentation, treatment, and outcome of patients with mycotic aneurysms. We then synthesized the available data into a combined cohort to more closely estimate the true demographic and clinical characteristics of this disease. We follow by presenting a comprehensive review of mycotic aneurysms, highlighting current treatment paradigms. The literature supports the administration of antibiotics in conjunction with surgical or endovascular intervention depending on the character and location of the aneurysm, as well as the clinical status of the patient. Mycotic aneurysms comprise an important subtype of potentially life-threatening cerebrovascular lesions, and further prospective studies are warranted to define outcome following both conservative and surgical or endovascular treatment.


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