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Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

Responses to aruba: a systematic review

J Neurosurg 126:486–494, 2017

The ARUBA study (A Randomized Trial of Unruptured Brain Arteriovenous Malformations [AVMs]) on unruptured brain AVMs has been the object of comments and editorials. In the present study the authors aim to systematically review critiques, discuss design issues, and propose a framework for future trials.

Methods: The authors performed a systematic review of the French and English literature on the ARUBA study published between January 2006 and February 2015. The electronic search, including the Cochrane Library, MEDLINE (PubMed and Ovid), CINAHL, and EMBASE databases, was complemented by hand searching and cross-referencing. The comments were categorized as items related to the design, the conduct, and the analysis and interpretation of the trial.

Results: Thirty-one articles or letters were identified. The pragmatic design, with heterogeneity of patients and lack of standardization of the treatment arm, were frequently stated concerns. The choice of outcome measures was repeatedly criticized. During the trial, low enrollment rates, selection bias, and premature interruption of enrollment were frequent comments. The short follow-up period, the lack of subgroup analyses, the lack of details on the results of the various treatments, and a contentious interpretation of results were noted at the analysis stage. A fundamental problem was the primary hypothesis testing conservative management. The authors believe that other trials are needed. Future trials could be pragmatic, test interventions stratified at the time of randomization, and look for long-term, hard clinical out- comes in a large number of patients.

Conclusions: In the authors’ view, the ARUBA trial is a turning point in the history of brain AVM management; future trials should aim at integrating trial methodology and clinical care in the presence of uncertainty.

Transulcal parafascicular minimally invasive approach to deep and subcortical cavernomas

J Neurosurg 125:1360–1366, 2016

Cavernomas comprise 8%–15% of intracranial vascular lesions, usually supratentorial in location and superficial. Cavernomas in the thalamus or subcortical white matter represent a unique challenge for surgeons in trying to identify and then use a safe corridor to access and resect the pathology.

Previous authors have described specific open microsurgical corridors based on pathology location, often with technical difficulty and morbidity.

This series presents 2 cavernomas that were resected using a minimally invasive approach that is less technically demanding and has a good safety profile. The authors report 2 cases of cavernoma: one in the thalamus and brainstem with multiple hemorrhages and the other in eloquent subcortical white matter. These lesions were resected through a transulcal parafascicular approach with a port-based minimally invasive technique.

In this series there was complete resection with no neurological complications. The transulcal parafascicular minimally invasive approach relies on image interpretation and trajectory planning, intraoperative navigation, cortical cannulation and subcortical space access, high-quality optics, and resection as key elements to minimize exposure and retraction and maximize tissue preservation. The authors applied this technique to 2 patients with cavernomas in eloquent locations with excellent outcomes.

 

Cotton-clipping and cotton-augmentation for aneurysms

cotton-clipping-and-cotton-augmentation-for-aneurysms

J Neurosurg 125:720–729, 2016

To address the challenges of microsurgically treating broad-based, frail, and otherwise complex aneurysms that are not amenable to direct clipping, alternative techniques have been developed. One such technique is to use cotton to augment clipping (“cotton-clipping” technique), which is also used to manage intraoperative aneurysm neck rupture, and another is to reinforce unclippable segments or remnants of aneurysm necks with cotton (“cottonaugmentation” technique). This study reviews the natural history of patients with aneurysms treated with cotton-clipping and cotton-augmentation techniques.

Methods The authors queried a database consisting of all patients with aneurysms treated at Barrow Neurological Institute in Phoenix, Arizona, between January 1, 2004, and December 31, 2014, to identify cases in which cotton-clipping or cotton-augmentation strategies had been used. Management was categorized as the cotton-clipping technique if cotton was used within the blades of the aneurysm clip and as the cotton-clipping technique if cotton was used to reinforce aneurysms or portions of the aneurysm that were unclippable due to the presence of perforators, atherosclerosis, or residual aneurysms. Data were reviewed to assess patient outcomes and annual rates of aneurysm recurrence or hemorrhage after the initial procedures were performed.

Results The authors identified 60 aneurysms treated with these techniques in 57 patients (18 patients with ruptured aneurysms and 39 patients with unruptured aneurysms) whose mean age was 53.1 years (median 55 years; range 24–72 years). Twenty-three aneurysms (11 cases of subarachnoid hemorrhage) were treated using cotton-clipping and 37 with cotton-augmentation techniques (7 cases of subarachnoid hemorrhage). In total, 18 patients presented with subarachnoid hemorrhage. The mean Glasgow Outcome Scale (GOS) score at the time of discharge was 4.4. At a mean follow-up of 60.9 ± 35.6 months (median 70 months; range 10–126 months), the mean GOS score at last follow-up was 4.8. The total number of patient follow-up years was 289.4. During the follow-up period, none of the cotton-clipped aneurysms increased in size, changed in configuration, or rebled. None of the patients experienced early rebleeding. The annual hemorrhage rate for aneurysms treated with cotton-augmentation was 0.52% and the recurrence rate was 1.03% per year. For all patients in the study, the overall risk of hemorrhage was 0.35% per year and the annual recurrence rate was 0.69%.

Conclusions Cotton-clipping is an effective and durable treatment strategy for intraoperative aneurysm rupture and for management of broad-based aneurysms. Cotton-augmentation can be safely used to manage unclippable or partially clipped intracranial aneurysms and affords protection from early aneurysm re-rupture and a relatively low rate of late rehemorrhage.

A new comorbidities index for risk stratification for treatment of unruptured cerebral aneurysms

Aneurysm surgery

J Neurosurg 125:713–719, 2016

Comorbidities have an impact on risk stratification for outcomes in analyses of large patient databases. Although the Charlson Comorbidity Index (CCI) and the Elixhauser Comorbidity Index (ECI) are the most commonly used comorbidity indexes, these have not been validated for patients with unruptured cerebral aneurysms; therefore, the authors created a comorbidity index specific to these patients.

Methods The authors extracted all records involving unruptured cerebral aneurysms treated with clipping, coiling, or both from the Nationwide Inpatient Sample (2002–2010). They assessed the effect of 37 variables on poor outcome and used the results to create a risk score for these patients. The authors used a validation data set and bootstrapping to evaluate the new index and compared it to CCI and ECI in prediction of poor outcome, mortality, length of stay, and hospital charges.

Results The index assigns integer values (-2 to 7) to 20 comorbidities: neurological disorder, renal insufficiency, gastrointestinal bleeding, paralysis, acute myocardial infarction, electrolyte disorder, weight loss, metastatic cancer, drug abuse, arrhythmia, coagulopathy, cerebrovascular accident, psychosis, alcoholism, perivascular disease, valvular disease, tobacco use, hypothyroidism, depression, and hypercholesterolemia. Values are summed to determine a patient’s risk score. The new index was better at predicting poor outcome than CCI or ECI (area under the receiver operating characteristic curve [AUC] 0.814 [95% CI 0.798–0.830], vs 0.694 and 0.712, respectively, for the other indices), and it was also better at predicting mortality (AUC 0.775 [95% CI 0.754–0.792], vs 0.635 and 0.657, respectively, for CCI and ECI).

Conclusions This new comorbidity index outperforms the CCI and ECI in predicting poor outcome, mortality, length of stay, and total charges for patients with unruptured cerebral aneurysm. Reevaluation of other patient cohorts is warranted to determine the impact of more accurate patient stratification.

Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy

Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy

J Neurosurg 125:264–268, 2016

Unruptured posterior communicating artery (PCoA) aneurysms with oculomotor nerve palsy (ONP) have a very high risk of rupture. This study investigated the hemodynamic and morphological characteristics of intracranial aneurysms with high rupture risk by analyzing PCoA aneurysms with ONP.

Methods: Fourteen unruptured PCoA aneurysms with ONP, 33 ruptured PCoA aneurysms, and 21 asymptomatic unruptured PCoA aneurysms were included in this study. The clinical, morphological, and hemodynamic characteristics were compared among the different groups.

Results: The clinical characteristics did not differ among the 3 groups (p > 0.05), whereas the morphological and hemodynamic analyses showed that size, aspect ratio, size ratio, undulation index, nonsphericity index, ellipticity index, normalized wall shear stress (WSS), and percentage of low WSS area differed significantly (p < 0.05) among the 3 groups. Furthermore, multiple comparisons revealed that these parameters differed significantly between the ONP group and the asymptomatic unruptured group and between the ruptured group and the asymptomatic unruptured group, except for size, which differed significantly only between the ONP group and the asymptomatic unruptured group (p = 0.0005). No morphological or hemodynamic parameters differed between the ONP group and the ruptured group.

Conclusions: Unruptured PCoA aneurysms with ONP demonstrated a distinctive morphological-hemodynamic pattern that was significantly different compared with asymptomatic unruptured PCoA aneurysms and was similar to ruptured PCoA aneurysms. The larger size, more irregular shape, and lower WSS might be related to the high rupture risk of PCoA aneurysms.

Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage

Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage

J Neurosurg 125:128–136, 2016

This prospective study investigated the role of whole-brain CT perfusion (CTP) studies in the identification of patients at risk for delayed ischemic neurological deficits (DIND) and of tissue at risk for delayed cerebral infarction (DCI).

Methods: Forty-three patients with aneurysmal subarachnoid hemorrhage (aSAH) were included in this study. A CTP study was routinely performed in the early phase (Day 3). The CTP study was repeated in cases of transcranial Doppler sonography (TCD)–measured blood flow velocity (BFV) increase of > 50 cm/sec within 24 hours and/or on Day 7 in patients who were intubated/sedated.

Results: Early CTP studies revealed perfusion deficits in 14 patients, of whom 10 patients (72%) developed DIND, and 6 of these 10 patients (60%) had DCI. Three of the 14 patients (21%) with early perfusion deficits developed DCI without having had DIND, and the remaining patient (7%) had neither DIND nor DCI. There was a statistically significant correlation between early perfusion deficits and occurrence of DIND and DCI (p < 0.0001). A repeated CTP was performed in 8 patients with a TCD–measured BFV increase > 50 cm/sec within 24 hours, revealing a perfusion deficit in 3 of them (38%). Two of the 3 patients (67%) developed DCI without preceding DIND and 1 patient (33%) had DIND without DCI. In 4 of the 7 patients (57%) who were sedated and/or comatose, additional CTP studies on Day 7 showed perfusion deficits. All 4 patients developed DCI.

Conclusions: Whole-brain CTP on Day 3 after aSAH allows early and reliable identification of patients at risk for DIND and tissue at risk for DCI. Additional CTP investigations, guided by TCD–measured BFV increase or persisting coma, do not contribute to information gain.

Dural arteriovenous fistula–induced thalamic dementia

Thalamic DAVF

J Neurosurg 124:1752–1765, 2016

Nonhemorrhagic neurological deficits are underrecognized symptoms of intracranial dural arteriovenous fistulas (dAVFs) having cortical venous drainage. These symptoms are the consequence of cortical venous hypertension and portend a clinical course with increased risk of neurological morbidity and mortality. One rarely documented and easily misinterpreted type of nonhemorrhagic neurological deficit is progressive dementia, which can result from venous hypertension in the cortex or in bilateral thalami. The latter, which is due to dAVF drainage into the deep venous system, is the less common of these 2 dementia syndromes.

Herein, the authors report 4 cases of dAVF with venous drainage into the vein of Galen causing bithalamic edema and rapidly progressive dementia. Two patients were treated successfully with endovascular embolization, and the other 2 patients were treated successfully with endovascular embolization followed by surgery. The radiographic abnormalities and presenting symptoms rapidly resolved after dAVF obliteration in all 4 cases. Detailed descriptions of these 4 cases are presented along with a critical review of 15 previously reported cases.

In our analysis of these 19 published cases, the following were emphasized: 1) the clinical and radiographic differences between dAVF-induced thalamic versus cortical dementia syndromes; 2) the differential diagnosis and necessary radiographic workup for patients presenting with a rapidly progressive thalamic dementia syndrome; 3) the frequency at which delays in diagnosis occurred and potentially dangerous and avoidable diagnostic procedures were used; and 4) the rapidity and completeness of symptom resolution following dAVF treatment.

Decompressive hemicraniectomy: predictors of functional outcome in patients with ischemic stroke

Decompressive hemicraniectomy

J Neurosurg 124:1773–1779, 2016

Patients presenting with large-territory ischemic strokes may develop intractable cerebral edema that puts them at risk of death unless intervention is performed. The purpose of this study was to identify predictors of outcome for decompressive hemicraniectomy (DH) in ischemic stroke.

Methods: The authors conducted a retrospective electronic medical record review of 1624 patients from 2006 to 2014. Subjects were screened for DH secondary to ischemic stroke involving the middle cerebral artery, internal carotid artery, or both. Ninety-five individuals were identified. Univariate and multivariate analyses were performed for an array of clinical variables in relationship to functional outcome according to the modified Rankin Scale (mRS). Clinical outcome was assessed at 90 days and at the latest follow-up (mean duration 16.5 months).

Results: The mean mRS score at 90 days and at the latest follow-up post-DH was 4. Good functional outcome was observed in 40% of patients at 90 days and in 48% of patient at the latest follow-up. The mortality rate at 90 days was 18% and at the last follow-up 20%. Univariate analysis identified a greater likelihood of poor functional outcome (mRS scores of 4–6) in patients with a history of stroke (OR 6.54 [95% CI 1.39–30.66]; p = 0.017), peak midline shift (MLS) > 10 mm (OR 3.35 [95% CI 1.33–8.47]; p = 0.011), or a history of myocardial infarction (OR 8.95 [95% CI 1.10–72.76]; p = 0.04). Multivariate analysis demonstrated elevated odds of poor functional outcome associated with a history of stroke (OR 9.14 [95% CI 1.78–47.05]; p = 0.008), MLS > 10 mm (OR 5.15 [95% CI 1.58–16.79; p = 0.007), a history of diabetes (OR 5.63 [95% CI 1.52–20.88]; p = 0.01), delayed time from onset of stroke to DH (OR 1.32 [95% CI 1.02–1.72]; p = 0.037), and evidence of pupillary dilation prior to DH (OR 4.19 [95% CI 1.06–16.51]; p = 0.04). Patients with infarction involving the dominant hemisphere had higher odds of unfavorable functional outcome at 90 days (OR 4.73 [95% CI 1.36–16.44]; p = 0.014), but at the latest follow-up, cerebral dominance was not significantly related to outcome (OR 1.63 [95% CI 0.61–4.34]; p = 0.328).

Conclusions: History of stroke, diabetes, myocardial infarction, peak MLS > 10 mm, increasing duration from onset of stroke to DH, and presence of pupillary dilation prior to intervention are associated with a worse functional outcome.

Intracranial-to-intracranial bypass for posterior inferior cerebellar artery aneurysms

Intracranial-to-intracranial bypass for posterior inferior cerebellar artery aneurysms

J Neurosurg 124:1275–1286, 2016

Intracranial-to-intracranial (IC-IC) bypasses are alternatives to traditional extracranial-to-intracranial (ECIC) bypasses to reanastomose parent arteries, reimplant efferent branches, revascularize branches with in situ donor arteries, and reconstruct bifurcations with interposition grafts that are entirely intracranial. These bypasses represent an evolution in bypass surgery from using scalp arteries and remote donor sites toward a more local and reconstructive approach. IC-IC bypass can be utilized preferentially when revascularization is needed in the management of complex aneurysms. Experiences using IC-IC bypass, as applied to posterior inferior cerebellar artery (PICA) aneurysms in 35 patients, were reviewed.

Methods: Patients with PICA aneurysms and vertebral artery (VA) aneurysms involving the PICA’s origin were identified from a prospectively maintained database of the Vascular Neurosurgery Service, and patients who underwent bypass procedures for PICA revascularization were included.

Results: During a 17-year period in which 129 PICA aneurysms in 125 patients were treated microsurgically, 35 ICIC bypasses were performed as part of PICA aneurysm management, including in situ p3-p3 PICA-PICA bypass in 11 patients (31%), PICA reimplantation in 9 patients (26%), reanastomosis in 14 patients (40%), and 1 V3 VA-to-PICA bypass with an interposition graft (3%). All aneurysms were completely or nearly completely obliterated, 94% of bypasses were patent, 77% of patients were improved or unchanged after treatment, and good outcomes (modified Rankin Scale ≤ 2) were observed in 76% of patients. Two patients died expectantly. Ischemic complications were limited to 2 patients in whom the bypasses occluded, and permanent lower cranial nerve morbidity was limited to 3 patients and did not compromise independent function in any of the patients.

Conclusions: PICA aneurysms receive the application of IC-IC bypass better than any other aneurysm, with nearly one-quarter of all PICA aneurysms treated microsurgically at our center requiring bypass without a single EC-IC bypass. The selection of PICA bypass is almost algorithmic: trapped aneurysms at the PICA origin or p1 segment are revascularized with a PICA-PICA bypass, with PICA reimplantation as an alternative; trapped p2 segment aneurysms are reanastomosed, bypassed in situ, or reimplanted; distal p3 segment aneurysms are reanastomosed or revascularized with a PICA-PICA bypass; and aneurysms of the p4 segment that are too distal for PICA-PICA bypass are reanastomosed. Interposition grafts are reserved for when these 3 primary options are unsuitable. A constructive approach that preserves the PICA with direct clipping or replaces flow with a bypass when sacrificed should remain an alternative to deconstructive PICA occlusion and endovascular coiling when complete aneurysm occlusion is unlikely.

Microembolism after endovascular coiling of unruptured cerebral aneurysms: incidence and risk factors

Microembolism after endovascular coiling of unruptured cerebral aneurysms

J Neurosurg 124:777–783, 2016

The incidence and risk factors of microembolic lesions on MR diffusion-weighted imaging (DWI) were analyzed after the endovascular coiling of unruptured intracranial aneurysms (UIAs).

Methods Data obtained from 271 consecutive patients (70 men and 201 women; median age 57 years; range 23–79 years) who presented with UIA for coil embolization between July 2011 and June 2013 were analyzed. Two independent reviewers examined the DWI and apparent diffusion coefficient maps obtained the following day for the presence of restrictive diffusion spots and counted the number of spots. Multivariate analysis was then performed to identify independent risk factors for developing microembolism following the coiling of an aneurysm.

Results Microembolic lesions were noted in 101 of 271 patients (37.3%). The results of the multivariate analysis showed that the following factors significantly influenced the risk for microembolism: age, diabetes, previous history of ischemic stroke, high-signal FLAIR lesions in the white matter, multiple aneurysms, and the insertion of an Enterprise stent (all ORs > 1.0 and all p values < 0.05). Previously known risk factors such as prolonged procedure duration, aneurysm size, and decreased antiplatelet function did not show any significant influence.

Conclusions The incidence of microembolism after endovascular coiling of UIA was not low. Lesions occurred more frequently in patients with vascular status associated with old age, diabetes, and previous stroke. Aneurysm multiplicity and the type of stent used for treatment also influenced lesion occurrence.

Height of aneurysm neck and estimated extent of brain retraction: powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms

Height of aneurysm neck and estimated extent of brain retraction- powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms

J Neurosurg 124:720–725, 2016

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction.

Methods A total of 102 patients who underwent a pterional or superciliary keyhole approach to clip an unruptured ACoA aneurysm from 2006 to 2013 were included in this study. Those patients who complained of permanent olfactory dysfunction after their aneurysm surgery, during a postoperative office visit or a telephone interview, were invited to undergo an olfactory test, the Korean version of the Sniffin’ Sticks test. In addition, the angiographic characteristics of ACoA aneurysms, including the maximum diameter, the projecting direction of the aneurysm, and the height of the neck of the aneurysm, were all recorded based on digital subtraction angiography and sagittal brain images reconstructed using CT angiography. Furthermore, the extent of the brain retraction was estimated based on the height of the ACoA aneurysm neck.

Results Eleven patients (10.8%) exhibited objective olfactory dysfunction in the Sniffin’ Sticks test, among whom 9 were anosmic and 2 were hyposmic. Univariate and multivariate analyses revealed that the direction of the ACoA aneurysm, ACoA aneurysm neck height, and estimated extent of brain retraction were statistically significant risk factors for postoperative olfactory dysfunction. Based on a receiver operating characteristic (ROC) analysis, an ACoA aneurysm neck height > 9 mm and estimated brain retraction > 12 mm were chosen as the optimal cutoff values for differentiating anosmic/hyposmic from normosmic patients. The values for the area under the ROC curves were 0.939 and 0.961, respectively.

Conclusions In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction.

Continuous cisternal irrigation with Mg solution for vasospasm

Mg sulfate irrigation

J Neurosurg 124:18–26, 2016

Although cerebral vasospasm (CV) is one of the most important predictors for the outcome in patients with subarachnoid hemorrhage (SAH), no treatment has yet been established for this condition. This study investigated the efficacy of continuous direct infusion of magnesium sulfate (MgSO4) solution into the intrathecal cistern in patients with an aneurysmal SAH.

Methods An SAH caused by a ruptured aneurysm was identified on CT scans within 72 hours after SAH onset. All patients were treated by surgical clipping and randomized into 2 groups: a control group of patients undergoing a standard treatment and a magnesium (Mg) group of patients additionally undergoing continuous infusion of 5 mmol/L MgSO4 solution for 14 days. The Mg2+ concentrations in serum and CSF were recorded daily. Neurological examinations were performed by intensive care clinicians. Delayed cerebral ischemia was monitored by CT or MRI. To assess the effect of the Mg treatment on CV, the CVs were graded on the basis of the relative degree of constriction visible on cerebral angiograms taken on Day 10 after the SAH, and transcranial Doppler ultrasonography was performed daily to measure blood flow velocity in the middle cerebral artery (MCA). Neurological outcomes and mortality rates were evaluated with the Glasgow Outcome Scale and modified Rankin Scale at 3 months after SAH onset.

Results Seventy-three patients admitted during the period of April 2008 to March 2013 were eligible and enrolled in this study. Three patients were excluded because of violation of protocol requirements. The 2 groups did not significantly differ in age, sex, World Federation of Neurosurgical Societies grade, or Fisher grade. In the Mg group, the Mg2+ concentration in CSF gradually increased from Day 4 after initiation of the continuous MgSO4 intrathecal administration. No such increase was observed in the control group. No significant changes in the serum Mg2+ levels were observed for 14 days, and no cardiovascular complications such as bradycardia or hypotension were observed in any of the patients. However, bradypnea was noted among patients in the Mg group. The Mg group had a significantly better CV grade than the control group (p < 0.05). Compared with the patients in the Mg group, those in the control group had a significantly elevated blood flow velocity in the MCA. Both groups were similar in the incidences of cerebral infarction, and the 2 groups also did not significantly differ in clinical outcomes.

Conclusions Continuous cisternal irrigation with MgSO4 solution starting on Day 4 and continuing to Day 14 significantly inhibited CV in patients with aneurysmal SAH without severe cardiovascular complications. However, this improvement in CV neither reduced the incidence of delayed cerebral ischemia nor improved the functional outcomes in patients with SAH.

Aneurysm location and clipping versus coiling for development of secondary normal-pressure hydrocephalus after aneurysmal subarachnoid hemorrhage

Hydrocephalus

J Neurosurg 123:1555–1561, 2015

The present study aimed to investigate aneurysm locations and treatments for ruptured cerebral aneurysms associated with secondary normal-pressure hydrocephalus (sNPH) after subarachnoid hemorrhage (SAH) by using comprehensive data from the Japanese Stroke DataBank.

Methods Among 101,165 patients with acute stroke registered between 2000 and 2013, 4693 patients (1482 men, 3211 women) were registered as having had an SAH caused by a ruptured saccular aneurysm. Of them, 1448 patients (438 men and 1010 women; mean age 61.9 ± 13.4 years) who were confirmed to have or not have coexisting acute hydrocephalus and sNPH were included for statistical analyses. Locations of the ruptured aneurysms were subcategorized into 1 of the following 4 groups: middle cerebral artery (MCA; n = 354), anterior communicating artery and anterior cerebral artery (ACA; n = 496), internal carotid artery (ICA; n = 402), and posterior circulation (n = 130). Locations of 66 of the ruptured aneurysms were unknown/unrecorded. Treatments included craniotomy and clipping alone in 1073 patients, endovascular coil embolization alone in 285 patients, and a combination of coiling and clipping in 17 patients. The age-adjusted and multivariate odds ratios from logistic regression analyses were calculated after stratification using the Fisher CT scale to investigate the effects of the hematoma volume of SAH.

Results Acute hydrocephalus was confirmed in 593 patients, and 521 patients developed sNPH. Patients with a ruptured ACA aneurysm had twice the risk for sNPH over those with a ruptured MCA aneurysm. Those with an ACA aneurysm with Fisher Grade 3 SAH had a 9-fold-higher risk for sNPH than those with an MCA aneurysm with Fisher Grade 1 or 2 SAH. Patients with a ruptured posterior circulation aneurysm did not have any significant risk for sNPH. Clipping of the ruptured aneurysm resulted in twice the risk for sNPH over coil embolization alone.

Conclusions Patients with low-grade SAH caused by a ruptured MCA aneurysm had a low risk for the development of sNPH. In contrast, patients with high-grade SAH caused by a ruptured ACA aneurysm had a higher risk for sNPH. Endovascular coiling might confer a lower risk of developing sNPH than microsurgical clipping.

Morphological aspects of blister aneurysms and nuances for surgical treatment

blister aneurysms

J Neurosurg 123:1156–1165, 2015

Blister aneurysms of the supraclinoid part of the internal carotid artery (ICA) are known for their high morbidity and mortality rates related to treatment, regardless of whether the treatment is surgical or endovascular. However, this grim prognosis is based on results that indiscriminately group all blister aneurysms together without taking into account the heterogeneous appearance of these lesions. The goal of this study was 2-fold: to determine whether different blister aneurysm morphologies present different pitfalls, which would then require different surgical strategies, as well as to determine whether there are identifiable subgroups of these types of aneurysms based on morphology.

Methods The authors reviewed the charts, cerebral catheter angiograms, surgical reports, and intraoperative videos of all ICA blister aneurysms treated surgically at the Centre Hospitalier de l’Université de Montréal from 2005 to 2012 to investigate whether there was a relationship between morphology and pitfalls, and whether different surgical strategies had been used according to these pitfalls. During this review process the authors noted 4 distinct morphological aspects. These 4 aspects led to a review of the English and French literature on blister aneurysms in which imaging was available, to determine whether other cases could also be classified into the same 4 subgroups based on these morphological aspects.

Results The retrospective review of the authors’ series of 10 patients allowed a division into 4 distinct subtypes: Type I (classic), Type II (berry-like), Type III (longitudinal), and Type IV (circumferential). These subtypes may at times be progressive stages in the arterial anomaly, and could represent a continuum. Each subtype described in this paper presented its own pitfalls and required specific surgical adaptations. Upon reviewing the literature the authors retained 35 studies involving a total of 61 cases of blister aneurysms, and all cases were able to be classified into 1 of these 4 distinct subtypes.

Conclusions Although they share some common characteristics, blister aneurysms may be divided into distinct subtypes, suggestive of a continuum. Such a classification with a detailed description of each type of blister aneurysm would allow for better recognition to anticipate complications during intervention and better assess the different treatment strategies according to the subtypes.

The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

The 6 thalamic regions- surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

J Neurosurg 123:676–685, 2015

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

Methods The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author’s surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricular for Region 5; and supracerebellar-infratentorial for Region 6.

Results Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months–9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0–2) and 6 (13%) had poor outcome (mRS scores 3–4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

Conclusions The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors’ experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach for a specific region.

The Barrow Ruptured Aneurysm Trial: 6-year results

Aneurysm surgery

J Neurosurg 123:609–617, 2015

The authors report the 6-year results of the Barrow Ruptured Aneurysm Trial (BRAT). This ongoing randomized trial, with the final goal of a 10-year follow-up, compares the safety and efficacy of surgical clip occlusion and endovascular coil embolization in patients presenting with subarachnoid hemorrhage (SAH) from a ruptured aneurysm. The 1- and 3-year results of this trial have been previously reported.

Methods In total, 500 patients with an SAH met the entry criteria and were enrolled in the study. Of these patients, 471 were randomly assigned to the treatments: 238 to surgical clipping and 233 to endovascular coiling. Six patients who died before treatment and 57 patients with nonaneurysmal SAHs were excluded, leaving a total of 408 patients who underwent clipping (209 assigned) or coiling (199 assigned). Whether to treat patients within the assigned group or to cross over patients to the other group was at the discretion of the treating physician; 38% (75/199) of the patients assigned to coiling were crossed over to clipping and 1.9% (4/209) assigned to clipping were crossed over to coiling. The outcome data were collected by a dedicated nurse practitioner. The primary outcome analysis was based on the assigned treatment group; poor outcome was defined as a modified Rankin Scale (mRS) score > 2 and was independently adjudicated. Six years after randomization, 336 (82%) of 408 patients who had been treated were available for examination.

Results On the basis of an mRS score of > 2, and similar to the results at the 3-year follow-up, no significant difference in outcomes (p = 0.24) was detected between the 2 treatment groups. Complete aneurysm obliteration at 6 years was achieved in 96% (111/116) of the clipping group and in 48% (23/48) of the coiling group (p < 0.0001). In the period between the 3- and 6-year follow-ups, 3 additional patients assigned to coiling and none assigned to clipping received retreatment, for overall retreatment rates of 4.6% (13/280) for clipping and 16.4% (21/128) for coiling (p < 0.0001). When aneurysm location was considered, the 6-year results continued to match the previously reported results, with no difference in outcome for anterior circulation aneurysms at most time points. Of the anterior circulation aneurysms assigned to coiling treatment, 42% (70/168) were crossed over to clipping treatment. The outcomes for posterior circulation aneurysms continued to favor coiling. The randomization process was unexpectedly skewed, with 18 of 21 treated aneurysms of the posterior inferior cerebellar artery (PICA) being assigned to clipping, but even when PICA aneurysms were removed from the analysis, outcomes for the posterior circulation aneurysms still favored coiling.

Conclusions Although BRAT was statistically underpowered to detect small differences, these results suggest little difference in outcome between the 2 treatments for anterior circulation aneurysms. This was not the case for the posterior circulation aneurysms, where coil embolization appeared to provide a sustained advantage over clipping. Aneurysm obliteration rates in BRAT were significantly lower and retreatment rates significantly higher in the patients undergoing coiling than in those undergoing clipping. However, despite the fact that retreatment rates were higher after coiling, no recurrent hemorrhages were known to have occurred in patients undergoing coiling in BRAT who were followed up for 6 years. Sufficient questions remain about the relative benefits of the 2 treatment modalities to warrant further welldesigned randomized trials.

The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes

Cavernous_Malformation_of_Thalamus

J Neurosurg (123)3: 676-685

The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.

METHODS
The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author’s surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6.

RESULTS
Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0–2) and 6 (13%) had poor outcome (mRS scores 3–4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.

CONCLUSIONS
The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors’ experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach for a specific region.

Isolated cortical vein thrombosis

Isolated cortical vein thrombosis

J Neurosurg 123:427–433, 2015

Isolated cortical vein thrombosis (ICVT) accounts for less than 1% of all cerebral infarctions. ICVT may cause irreversible parenchymal damage, rendering early and accurate diagnosis critical. This case series and literature review presents the clinical and radiological findings in 7 patients with ICVT, and highlights risk factors and imaging modalities that may be most beneficial in rendering an accurate and timely diagnosis.

Methods Patients with CT and MRI findings consistent with ICVT examined between January 2011 and June 2014 were included in this retrospective review.

Results Seven patients (5 females, 2 males), ranging in age from 11 months to 34 years, met the inclusion criteria. The most common clinical presentations were headaches (n = 4) and seizures (n = 3). The most common comorbidities noted in these patients were hypercoagulable states (n = 4) and intracranial hypotension (n = 3). Five patients had intraparenchymal involvement. CT suggested the correct diagnosis in 4 patients, and MRI confirmed the diagnosis in all 7 patients. All patients who received anticoagulation therapy (n = 5) experienced complete resolution of their symptoms.

Conclusions The majority of these patients were adult females, consistent with published data. Seizures and headaches were the most common presenting symptoms. Hypercoagulable state and intracranial hypotension, both known risk factors for thrombosis, were the most commonly noted ICVT risk factors. Intraparenchymal involvement was prevalent in nearly all ICVT cases and presented as vasogenic edema, early intraparenchymal hemorrhage, or hemorrhagic venous infarction. Susceptibility-weighted imaging was the most sensitive imaging technique in diagnosing ICVT.

Venous organization in the transverse foramen

Venous organization in the transverse foramen

J Neurosurg 123:118–125, 2015

The anatomical arrangement of the venous system within the transverse foramen is controversial; there is disagreement whether the anatomy consists of a single vertebral vein or a confluence of venous plexus. Precise knowledge of this arrangement is necessary in imaging when vertebral artery dissection is suspected, as well as in surgical approaches for the cervical spine. This study aimed to better explain anatomical organization of the venous system within the transverse foramen according to the Trolard hypothesis of a transverse vertebral sinus.

Methods This was an anatomical and radiological study. For the anatomical study, 10 specimens were analyzed after vascular injection. After dissection, histological cuts were prepared. For the radiological study, a high-resolution MRI study with 2D time-of-flight segment MR venography sequences was performed on 10 healthy volunteers.

Results Vertebral veins are arranged in a plexiform manner within the transverse canal. This arrangement begins at the upper part of the transverse canal before the vertebral vein turns into a single vein along with the vertebral artery running from the transverse foramen of the C-6. This venous system runs somewhat ventrolaterally to the vertebral artery. In most cases, this arrangement is symmetrical and facilitates radiological readings. The anastomoses between vertebral veins and ventral longitudinal veins are uniform and arranged segmentally at each vertebra.

Conclusions These findings confirm recent or previous anatomical descriptions and invalidate others. It is hard to come up with a common description of the arrangement of vertebral veins. The authors suggest providing clinicians as well as anatomists with a well-detailed description of components essential to the understanding of this organization.

Comparison of language cortex reorganization patterns between cerebral arteriovenous malformations and gliomas: a functional MRI study

Comparison of language cortex reorganization patterns between cerebral arteriovenous malformations and gliomas- a functional MRI study

J Neurosurg 122:996–1003, 2015

Cerebral arteriovenous malformations (AVMs) are congenital malformations that may grow in the language cortex but usually do not lead to aphasia. In contrast, language dysfunction is a common presentation for patients with a glioma that involves language areas. The authors attempted to demonstrate the difference in patterns of language cortex reorganization between cerebral AVMs and gliomas by blood oxygen level–dependent (BOLD) functional MRI (fMRI) evaluation.

Methods The authors retrospectively reviewed clinical and imaging data of 63 patients with an unruptured cerebral AVM (AVM group) and 38 patients with a glioma (glioma group) who underwent fMRI. All the patients were right handed, and all their lesions were located in the left cerebral hemisphere. Patients were further categorized into 1 of the 2 following subgroups according to their lesion location: the BA subgroup (overlying or adjacent to the inferior frontal or the middle frontal gyri [the Broca area]) and the WA subgroup (overlying or adjacent to the supramarginal, angular, or superior temporal gyri [the Wernicke area]). Lateralization indices of BOLD signal activations were calculated separately for the Broca and Wernicke areas. Statistical analysis was performed to identify the difference in patterns of language cortex reorganization between the 2 groups.

Results In the AVM group, right-sided lateralization of BOLD signal activations was observed in 23 patients (36.5%), including 6 with right-sided lateralization in the Broca area alone, 12 in the Wernicke area alone, and 5 in both areas. More specifically, in the 34 patients in the AVM-BA subgroup, right-sided lateralization of the Broca area was detected in 9 patients (26.5%), and right-sided lateralization of the Wernicke area was detected in 4 (11.8%); in the 29 patients in the AVM-WA subgroup, 2 (6.9%) had right-sided lateralization of the Broca area, and 13 (44.8%) had right-sided lateralization of the Wernicke area. In the glioma group, 6 patients (15.8%) showed right-sided lateralization of the Wernicke area, including 2 patients in the glioma-BA subgroup and 4 patients in the glioma-WA subgroup. No patient showed right-sided lateralization of the Broca area. Moreover, although the incidence of right-sided lateralization was higher in cases of low-grade gliomas (5 in 26 [19.2%]) than in high-grade gliomas (1 in 12 [8.3%]), no significant difference was detected between them (p = 0.643). Compared with the AVM group, the incidence of aphasia was significantly higher (p < 0.001), and right-sided lateralization of language areas was significantly rarer (p = 0.026) in the glioma group.

Conclusions Right-sided lateralization of BOLD signal activations was observed in patients with a cerebral AVM and in those with a glioma, suggesting that language cortex reorganization may occur with both diseases. However, the potential of reorganization in patients with gliomas seems to be insufficient compared with patients AVMs, which is suggested by clinical manifestations and the fMRI findings. Moreover, this study seems to indicate that in patients with an AVM, a nidus near the Broca area mainly leads to right-sided lateralization of the Broca area, and a nidus near the Wernicke area mainly leads to right-sided lateralization of the Wernicke area.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain

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