Category: Vascular

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Prognostic Value of the Amount of Bleeding After Aneurysmal Subarachnoid Hemorrhage: A Quantitative Volumetric Study

SAH

Neurosurgery 77:898–907, 2015

Quantitative estimation of the hemorrhage volume associated with aneurysm rupture is a new tool of assessing prognosis.

OBJECTIVE: To determine the prognostic value of the quantitative estimation of the amount of bleeding after aneurysmal subarachnoid hemorrhage, as well the relative importance of this factor related to other prognostic indicators, and to establish a possible cut-off value of volume of bleeding related to poor outcome.

METHODS: A prospective cohort of 206 patients consecutively admitted with the diagnosis of aneurysmal subarachnoid hemorrhage to Hospital 12 de Octubre were included in the study. Subarachnoid, intraventricular, intracerebral, and total bleeding volumes were calculated using analytic software. For assessing factors related to prognosis, univariate and multivariate analysis (logistic regression) were performed. The relative importance of factors in determining prognosis was established by calculating their proportion of explained variation. Maximum Youden index was calculated to determine the optimal cut point for subarachnoid and total bleeding volume.

RESULTS: Variables independently related to prognosis were clinical grade at admission, age, and the different bleeding volumes. The proportion of variance explained is higher for subarachnoid bleeding. The optimal cut point related to poor prognosis is a volume of 20 mL both for subarachnoid and total bleeding.

CONCLUSION: Volumetric measurement of subarachnoid or total bleeding volume are both independent prognostic factors in patients with aneurysmal subarachnoid hemorrhage. A volume of more than 20 mL of blood in the initial noncontrast computed tomography is related to a clear increase in poor outcome risk.

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In-Pipeline Stenosis: Incidence, Predictors, and Clinical Outcomes

In-Pipeline Stenosis- Incidence, Predictors, and Clinical Outcomes

Neurosurgery 77:875–879, 2015

The Pipeline Embolization Device is a widely utilized flow diverter in the treatment of intracranial aneurysms.

OBJECTIVE: To assess the incidence, clinical significance, predictors, and outcomes of in-Pipeline stenosis (IPS).

METHODS: Angiographic studies in 139 patients treated between 2011 and 2013 were independently reviewed by 2 authors for the presence of IPS. Multivariable logistic regression analysis was conducted to determine predictors of IPS.

RESULTS: A total of 21 (15.8%) patients demonstrated some degree of IPS during the follow-up period at a mean time point of 6.7 months (range, 3-24 months). The stenosis was mild (,50%) in 11 patients, moderate (50%-75%) in 5, and severe (.75%) in 6. None were symptomatic or required further intervention. Sixteen of these 22 patients (73%) had IPS detected within 6 months. IPS was noted in 7.6% (1/13) of patients with posterior circulation aneurysms vs 16.7% (21/126) of those with anterior circulation aneurysms (P = .03). The rate of IPS was 60% (3/5) in patients who did not receive aspirin vs only 14.2% (19/134) in those who received aspirin (P = .02). In multivariable analysis, no aspirin therapy (odds ratio, 10.0; 95% confidence interval, 1.4-67.7; P = .02) and internal carotid artery aneurysm location (odds ratio, 3.1; 95% confidence interval, 1.1-8.8; P = .03) were strong independent predictors of IPS.

CONCLUSION: IPS is a common, early, and mostly benign complication. Patients with internal carotid artery aneurysms are more likely to develop IPS. Aspirin plays a key role in preventing IPS. The results of this study further support the safety of flow diverters.

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Extended endoscopic endonasal transclival clipping of posterior circulation aneurysms

Extended endoscopic endonasal transclival clipping of posterior circulation aneurysms

Acta Neurochir (2015) 157:2077–2085

Transcranial clipping of most posterior circulation aneurysms is one of the most difficult procedures, with high morbidity, and endovascular coiling is an alternative with less risk, but is not devoid of complications and not suitable for all aneurysms. Here we describe four cases of posterior circulation aneurysms clipped via the extended endoscopic endonasal transclival route. To the best of our knowledge, this is the first report of basilar top and posterior cerebral artery aneurysms being clipped endonasally.

Methods and results Four patients with posterior circulation aneurysms underwent extended endoscopic endonasal transclival clipping of the aneurysm. The age range was 35– 70 years. There were two males and two females. Three of the four patients presented after the rupture of aneurysms, and the other patient presented with sudden-onset left hemiparesis probably due to thromboembolism from a large unruptured left posterior cerebral artery (PCA) aneurysm. On evaluation with four-vessel digital subtraction angiography (DSA), two patients had a basilar apex aneurysm, one had a basilar trunk aneurysm, and the other had a PCA (P1) aneurysm. Postoperatively, two patients had good recovery. One patient with a PCA aneurysm and another with a basilar apex aneurysm had fresh postoperative deficits. One patient developed postoperative CSF rhinorrhea.

Conclusion Endoscopic extended transnasal surgery is an expanding field in neurosurgery with a steep learning curve. With improvement in techniques and instrumentation the use of this approach for clipping posterior circulation aneurysms can become an effective alternative in the treatment of aneurysms.

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Seizure Outcomes in Patients With Surgically Treated Cerebral Arteriovenous Malformations

ICG and AVM

Neurosurgery 77:762–768, 2015

Epilepsy is the second most common symptom in cerebral arteriovenous malformation (AVM) patients. The consecutive reduction of life quality is a clinically underrated problem because treatment usually focuses on the prevention of intracerebral hemorrhage.

OBJECTIVE: To evaluate postoperative seizure outcome with the aim of more accurate counseling for postoperative seizure outcome.

METHODS: From 1985 to 2012, 293 patients with an AVM were surgically treated by J.S. One hundred twenty-six patients with preoperative seizures or epilepsy could be identified; 103 of 126 had a follow-up of at least 12 months and were included in the analysis. The different epilepsy subtypes were categorized (sporadic seizures, chronic epilepsy, drug-resistant epilepsy [DRE]). Preoperative workup and surgical technique were evaluated. Seizure outcome was analyzed by using International League Against Epilepsy classification.

RESULTS: Sporadic seizures were identified in 41% of patients (chronic epilepsy and DRE were identified in 36% and 23%, respectively). Detailed preoperative epileptological workup was done in 13%. Seizure freedom was achieved in 77% (79% at 5 years, 84% at 10 years). Outcome was significantly poorer in DRE cases. More extensive resection was performed in 11 cases with longstanding symptoms (.24 months) and resulted in better seizure outcome as well as the short duration of preoperative seizure history.

CONCLUSION: Patients presenting with AVM-associated epilepsy have a favorable seizure outcome after surgical treatment. Long-standing epilepsy and the progress into DRE markedly deteriorate the chances to obtain seizure freedom and should be considered an early factor in establishing the indication for AVM removal.

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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.

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Application of intraoperative motor evoked potential monitoring during giant internal carotid artery aneurysm surgery using prolonged temporary occlusion

Application of intraoperative motor evoked potential monitoring during giant internal carotid artery aneurysm surgery using prolonged temporary occlusion

Acta Neurochir (2015) 157:1833–1840

Clipping and bypass surgery are common therapeutic options for the management of giant internal carotid artery (ICA) aneurysms. However, potential ischemic risks may be exaggerated by prolonged temporary occlusion (PTO) during the surgery. Monitoring motor-evoked potentials (MEPs) is a sensitive technique for detecting potential ischemia intraoperatively. This preliminary study was designed to evaluate the effectiveness of applying MEP monitoring during giant ICA aneurysm surgery using PTO.

Methods From July 2009 to July 2012, 11 patients with giant ICA aneurysms who could not pass the preoperative hemodynamic evaluations were enrolled in this study. MEP monitoring was utilized intraoperatively in all cases. Clipping was performed if there were no significant MEP changes under PTO. A variant extracranial-to-intracranial (EC-IC) bypass was performed if there was reproducible loss of MEP signals after PTO or unclippable anatomic features.

Results Five patients underwent clipping alone and six underwent bypass. There were no significant differences in baseline clinical data between the two groups. The overall percentage of patients with good outcomes (Glasgow Outcome Score≥4) improved from 72.7 % (8/11) postoperatively to 90.9 % (10/11) after 26.0±9.5 months of follow-up. There were no significant differences between the clipping and bypass groups regarding short- and long-term outcomes (p=0.545 and p=1.000).

Conclusions MEP monitoring is useful for evaluating the safety of PTO, surgical strategy, and outcomes of giant ICA aneurysm surgery. Direct clipping during safe PTO under intraoperative MEP monitoring is applicable for giant ICA aneurysms. Its use achieved favorable outcomes by indicating the need for bypass surgery.

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Temporal lobe epilepsy and cavernous malformations: surgical strategies and long-term outcomes

Temporal lobe epilepsy and cavernous malformations- surgical strategies and long-term outcomes

Acta Neurochir (2015) 157:1887–1895

Cerebral cavernous malformations (CCM) of the temporal lobe often present with seizures. Surgical resection of these lesions can offer durable seizure control. There is, however, no universally accepted methodology for assessing and surgically treating these patients. We propose an algorithm to maximize positive surgical outcomes (seizure control) while minimizing post-surgical neurological deficit.

Methods A retrospective review of 34 patients who underwent epilepsy surgery for radiographically proven temporal lobe CCM was conducted. Patients underwent a relatively standard work-up for seizure localization. In patients with mesial temporal lobe epilepsy (MTLE), a complete resection of the epileptogenic zone was performed including amygdalo-hippocampectomy in addition to a lesionectomy if not contraindicated by pre-operative work-up. Patients with neocortical epilepsy underwent intraoperative electrocorticography (ECoG)-guided lesionectomy.

Results Seizure-free rate for mesial and neocortical (anterior, lateral, and basal) location was 90 vs. 83 %, respectively. Complete resection of the lesion, irrespective of location, was statistically significant for seizure control (p=0.018). There was no difference in seizure control based on disease duration or location (p>0.05). Patients with mesial temporal CCM who presented with MTLE were presumed to also have mesial temporal sclerosis (MTS), or dual pathology. These patients underwent routine resection of the mesial structures. Interestingly, patients who had MTLE and basal (neocortical) lesions who underwent a mesial resection for suspected MTS were found not to have dual pathology.

Conclusions Patients with temporal lobe CCM should be offered resection for durable seizure control, prevention of secondary epileptogenic foci, and elimination of hemorrhage risk. The preoperative work-up should follow a team approach. Surgical intervention should include complete lesionectomy in all cases. Intra or extra-operative ECoG for neocortical lesions may be beneficial. Management of mesial temporal CCMs (archicortex) should consider resection of a well-defined epileptogenic zone (including mesial structures) due to high probability of pathologically proven MTS. The use of this treatment algorithm is useful for the education and treatment of these patients.

Keywords Epilepsy , Cavernous malformation, Temporal lobe , Pathology

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Cost Comparison of Surgical and Endovascular Treatment of Unruptured Giant Intracranial Aneurysms

Virtual planning of different possible approaches for the surgical treatment of a giant carotid-ophthalmic aneurysm

Neurosurgery 77:733–743, 2015

Giant intracranial aneurysms (GIAs), which are defined as intracranial aneurysms (IAs) with a diameter of $25 mm, are most likely associated with the highest treatment costs of all IAs. However, the treatment costs of unruptured GIAs have so far not been reported. OBJECTIVE: To examine direct costs of endovascular and surgical treatment of unruptured GIAs.

METHODS: We retrospectively examined 55 patients with unruptured GIAs treated surgically (37 patients) or endovascularly (18 patients) between April 2004 and March 2014. We analyzed the costs of all hospital stays, interventions, and imaging with a median follow-up of 46 months.

RESULTS: There was no difference in the costs of hospital stay between surgical and endovascular treatment groups ($10 565 vs $14 992; P = .37). Imaging costs were significantly higher in the surgical group than in the endovascular treatment group ($2890 vs $1612; P < .01), as were the costs of the intervention room and personnel involved in the intervention ($5566 vs $1520; P < .01). Implants used per patient were more expensive in the endovascular group than in the surgical treatment group ($20885 vs $167). The total direct treatment costs were higher in the endovascular group ($52325) than in the surgical treatment group ($20619; P < .01). Treatment costs were associated with the type of treatment and GIA location but not with patient age, sex, or GIA size.

CONCLUSION: Endovascular GIA treatment produced higher direct costs than surgical GIA treatment mainly due to higher implant costs. Reducing endovascular implant costs may be the most effective tool to decrease direct costs of GIA treatment.

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Adenosine-induced transient asystole during intracranial aneurysm surgery

Adenosine-induced transient asystole

Acta Neurochir (2015) 157:1879–1886

Several flow-arrest techniques have been introduced for the treatment of complex aneurysms that cannot be treated with conventional clipping or endovascular coil embolization. Adenosine-induced transient asystole is an alternative method of flow arrest. However, given the limited number of studies that have reported on this topic, there is no consensus regarding the dose, regimen, efficacy, and potential risks of adenosine.

Method A total of 22 aneurysms in 22 different patients that underwent adenosine-induced transient asystole during aneurismal neck clipping within the past 4 years were retrospectively reviewed. Adenosine was administrated intravenously in a test-incremental manner (starting with 6–12 mg and then giving additional doses as needed) in 11 patients and in an estimated manner (pre-calculated as 0.3–0.4 mg/kg) in 11 patients.

Results Overall, the study consisted of 18 unruptured saccular aneurysms, three ruptured saccular aneurysms, and a ruptured pseudoaneurysm. Adenosine-induced transient asystole was used in cases of temporary clipping inability, wide necked aneurysm, deep-seated aneurysm, or a thin aneurysm wall. The number of administrations, dose (mg/kg in ideal body weight) and duration of asystole were 1–4 (mean, 2.3) times, 0.08–1.27 (mean, 0.36) mg/kg and 0–30 (mean 13) seconds in the test-incremental manner and 1–2 (mean, 1.09) times, 0.24–0.42 (mean, 0.34) mg/kg and 13–41 (mean, 24) seconds in the estimated manner, respectively. There was a linear relationship between the dose and the duration of asystole. Twenty out of 22 aneurysms were clipped successfully with adenosine-induced transient asystole. However, in the other two cases, additional suction decompression was required for the final clipping. Adenosine-related cardiologic complications occurred in two cases of self-limited atrial fibrillation during restoration of the cardiac rhythm.

Conclusions In our experience, adenosine-induced transient asystole was safe and helpful for satisfactory clipping of a complicated aneurysm. An estimated dose injection of adenosine was more convenient than the test-incremental method and did not result in serious cardiologic problems.

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Treatment strategies for dissecting aneurysms of the posterior cerebral artery

Treatment strategies for dissecting aneurysms of the posterior cerebral arteryActa Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique.We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

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Safety and efficacy of microsurgical treatment of previously coiled aneurysms: a systematic review and meta-analysis

coiledaneurysm

Acta Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique. We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

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Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Acta Neurochir (2015) 157:1659–1664

Spinal intramedullary arteriovenous malformations (AVMs) fed by an anterior spinal artery are surgically challenging vascular lesions.

Method We herein presented microsurgical resection techniques for an intramedullary glomus AVM located in the lateral part of the high cervical spinal cord with an operative video.

These techniques included (1) a lateral suboccipital approach via cervical hemilaminectomy in the lateral position; (2) retrograde dissection of the AVM located between the spinal tracts; (3) coagulation and division of multiple narrow sulcal branches of the anterior spinal artery.

Conclusion Patients who underwent these techniques achieved good outcomes with minimal bleeding and morbidity.

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Transvenous Approach to Intracranial Arteriovenous Malformations

Transvenous Approach to Intracranial Arteriovenous Malformations

Neurosurgery 77:644–652, 2015

A compartmental conceptualization of intracranial arteriovenous malformations (AVMs) allows recognition of feeding arteries, an intervening plexiform nidus, and draining veins. AVM therapy involves eliminating the nidus, which is the source of hemorrhage, without compromising normal arterial and venous drainage of the brain. Traditional methods of AVM therapy through microsurgery and endovascular embolization involve arterial devascularization, with preservation of AVM venous drainage, until the nidus is excluded.

The transvenous approach in treating vascular malformations was popularized by successful treatment models for dural arteriovenous fistulas. More recently, high-flow intracranial AVMs are being managed with transvenous endovascular approaches, although this novel technique has its challenges and perils.

We review the current literature on transvenous AVM therapy and highlight its role for AVM therapy in the present day.

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The lateral infratrigeminal transpontine window to deep pontine lesions

The lateral infratrigeminal transpontine window to deep pontine lesions

J Neurosurg 123:699–710, 2015

Surgery of brainstem lesions is increasingly performed despite the fact that surgical indications and techniques continue to be debated. The deep pons, in particular, continues to be a critical area in which the specific risks related to different surgical strategies continue to be examined. With the intention of bringing new knowledge into this important arena, the authors systematically examined the results of brainstem surgeries that have been performed through the lateral infratrigeminal transpontine window.

Methods Between 1990 and 2013, 29 consecutive patients underwent surgery through this window for either biopsy sampling or for removal of a deep pontine lesion. All of this work was performed at the Department of Neurosurgery of the Istituto Nazionale Neurologico “Carlo Besta”, in Milan, Italy. A retrospective analysis of the findings was conducted with the intention of bringing further clarity to this important surgical strategy.

Results The lateral infratrigeminal transpontine window was exposed through 4 different approaches: 1) classic retrosigmoid (15 cases), 2) minimally invasive keyhole retrosigmoid (10 cases), 3) translabyrinthine (1 case), and 4) combined petrosal (3 cases). No deaths occurred during the entire clinical study. The surgical complications that were observed included hydrocephalus (2 cases) and CSF leakage (1 case). In 6 (20.7%) of 29 patients the authors encountered new neurological deficits during the immediate postoperative period. All 6 of these patients had undergone lesion removal. In only 2 of these 6 patients were permanent sequelae observed at 3 months follow-up. These findings show that 93% of the patients studied did not report any permanent worsening of their neurological condition after this surgical intervention.

Conclusions This retrospective study supports the idea that the lateral infratrigeminal transpontine window is both a low-risk and safe corridor for either biopsy sampling or for removal of deep pontine lesions.

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Effect of Prior Embolization on Cerebral Arteriovenous Malformation Radiosurgery Outcomes

AVM

Neurosurgery 77:406–417, 2015

Embolization before stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVM) has been shown to negatively affect obliteration rates, but its impact on the risks of radiosurgery-induced complications and latency period hemorrhage is poorly defined.

OBJECTIVE: To determine, in a case-control study, the effect of prior embolization on AVM SRS outcomes.

METHODS: We evaluated a database of AVM patients who underwent SRS. Propensity score analysis was used to match the case (embolized nidi) and control (nonembolized nidi) cohorts. AVM angioarchitectural complexity was defined as the sum of the number of major feeding arteries and draining veins to the nidus. Multivariate Cox proportional hazards regression analyses were performed on the overall study population to determine independent predictors of obliteration and radiation-induced changes.

RESULTS: The matching process yielded 242 patients in each cohort. The actuarial obliteration rates were significantly lower in the embolized (31%, 49% at 5, 10 years, respectively) compared with the nonembolized (48%, 64% at 5, 10 years, respectively) cohort (P = .003). In the multivariate analysis for obliteration, lower angioarchitectural complexity (P , .001) and radiologically evident radiation-induced changes (P = .016) were independent predictors, but embolization was not significant (P = .744). In the multivariate analysis for radiologic radiation-induced changes, lack of prior embolization (P = .009) and fewer draining veins (P = .011) were independent predictors.

CONCLUSION: The effect of prior embolization on AVM obliteration after SRS may be significantly confounded by nidus angioarchitectural complexity. Additionally, embolization could reduce the risk of radiation-induced changes. Thus, combined embolization and SRS may be warranted for appropriately selected nidi.

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Spontaneous subarachnoid hemorrhage and negative initial vascular imaging—should further investigation depend upon the pattern of hemorrhage on the presenting CT?

Spontaneous subarachnoid hemorrhage and negative initial vascular imaging—should further investigation depend upon the pattern of hemorrhage on the presenting CT?

Acta Neurochir (2015) 157:1477–1484

Multiple investigations are usually performed in patients with spontaneous SAH who have negative initial angiography. This study aimed to evaluate the most appropriate use of additional imaging studies and how this may be influenced by the findings of the initial CT.

Methods A retrospective analysis was performed on a prospectively collected cohort of patients referred with spontaneous SAH and negative initial angiography. The patients were divided into four categories based upon the distribution of blood on the initial CT: perimesencephalic (pSAH), diffuse (dSAH), sulcal (sSAH) and CT negative (CSF positive for xanthochromia) (nCT-pLP). The number and nature of the subsequent imaging investigations were reviewed, and the results were correlated with the findings of the presenting CT.

Results One hundred fourteen patients were included in the study. Repeat imaging found five relevant abnormalities. Three cases of vasculitis were diagnosed on the first DSA following a negative CTA. A case of dissecting aneurysm was revealed on the third neurovascular study. A hemorrhagic spinal tumor presented with xanthochromia. No subsequent abnormality was found on the third DSA or MRI head. No case of pSAH had a subsequent positive finding if the initial CTA was negative.

Conclusions Certain patterns of SAH are associated with a low yield of abnormalities on repeat imaging if the initial angiography is normal. The authors believe that the pattern of hemorrhage on the presenting CT should be used to guide the most appropriate use of further imaging modalities and present a diagnostic algorithm for this purpose.

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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.

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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.

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International differences in the management of intracranial aneurysms: implications for the education of the next generation of neurosurgeons

MCA aneurysm

Acta Neurochir 2015, 157,(9):1467-1475

The publication of the International Subarachnoid Aneurysm Trial rapidly changed the management of patients with subarachnoid hemorrhage. The present and perceived future trends of aneurysm management have significant implications for patients and how we educate future cerebrovascular specialists.

Objective

To determine present perceived competencies of final-year neurosurgical residents who have just finished their residencies and to relate those to what practitioners from a variety of continents expect of these persons. The goal is to provide a basis for further discussion regarding the design of further educational programs in neurosurgery.

Methods

A 55-item questionnaire with 33 questions related to competencies and expectations of competency from final-year residents who have just finished residency was completed by 229 neurosurgeons and neuro-radiologists (81 % response rate) of mixed seniority from 45 countries. We used bivariate and descriptive analyses to determine future trends and geographic differences in cerebral aneurysm management as well as the educational implications on the future.

Results

More North Americans than those from the rest of the world are of the opinion that graduating residents are presently competent to perform basic cerebrovascular procedures like evacuation of a hematoma and clipping a simple 7-mm middle cerebral artery aneurysm. Extremely few graduating neurosurgical residents anywhere are presently capable of performing endovascular techniques for even the most basic of aneurysms. Most of those surveyed also believe that endovascular and open surgical management of aneurysms should be a part of residency training for all residents (70.4 and 88.7 %, respectively).

Conclusions

Our findings have implications for the design of neurosurgical curricula for residents as well as for certification examinations and procedures. Specialty and educational organizations and those responsible for the education of future clinicians who will care for patients with cerebrovascular problems should adjust educational objectives and implement curricula and learning experiences that will ensure that cerebrovascular specialists are capable of providing the best care possible to the patient with an aneurysm, whether that be open surgery or endovascular management. These findings mean that organizations around the world will need to make these adjustments to the education of future specialists.

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The unruptured intracranial aneurysm treatment score: A multidisciplinary consensus

The unruptured intracranial aneurysm treatment score A multidisciplinary consensus

Neurology 85(3):881-889 2015

We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research.

Methods: An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39 panel members involvedin identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agree-ment with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (vr*) (vr*5 0 indicating excellent agreement and vr*5 1 indicating poor agreement).

Results: The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1–4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1–4.4) for panel members and 4.5 (95% CI 4.3–4.6) for external reviewers (p5 0.017). Mean Likert scores were 4.2 (95% CI 4.1–4.3) for interventional reviewers (n5 56) and 4.1 (95% CI 3.9–4.4) for noninterventional reviewers (n5 12) (p5 0.290). Overall IRA (vr*) for both cohorts was 0.026 (95% CI 0.019–0.033).

Conclusions: This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA.

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