Endovascular intervention for bilateral paramedian thalamic stroke due to occlusion of the unilateral P1 segment of the posterior cerebral artery: illustrative cases

BACKGROUND

Occlusion of the unilateral P1 segment can result in bilateral paramedian thalamic infarction in patients with anatomical variants of the bilateral paramedian thalamic artery arising from a single P1 segment. Despite the life-threatening presentation of bilateral paramedian thalamic stroke, timely diagnosis is often challenging.

OBSERVATIONS

The authors herein describe 3 patients treated with endovascular intervention for occlusion of the unilateral P1 segment wherein the bilateral paramedian thalamic arteries arose. All patients were admitted to the authors' emergency department with sudden-onset coma and respiratory distress; however, initial computed tomography was unremarkable. Despite suspicion of basilar artery occlusion, vertebral and carotid angiography revealed occlusion of the unilateral P1 segment. All patients were successfully treated with endovascular intervention. Overall, 2 patients had favorable outcomes (modified Rankin scale [mRS] scores of 0 and 1), whereas in 1 patient, the mRS score reached a baseline score of 3.

LESSONS

In patients with the variant of the bilateral paramedian thalamic artery arising from a single P1 segment, occlusion of the unilateral P1 segment can be life threatening; nevertheless, timely endovascular treatment is effective. Carotid and vertebral angiography, rather than magnetic resonance or computed tomography angiography, is useful for immediate and reliable diagnosis of the relatively small vascular lesions.

Transcranial Doppler ultrasonography in neurological surgery and neurocritical care

Transcranial Doppler (TCD) ultrasonography is an inexpensive, noninvasive means of measuring blood flow within the arteries of the brain. In this review, the authors outline the technology underlying TCD ultrasonography and describe its uses in patients with neurosurgical diseases. One of the most common uses of TCD ultrasonography is monitoring for vasospasm following subarachnoid hemorrhage. In this setting, elevated blood flow velocities serve as a proxy for vasospasm and can herald the onset of ischemia. TCD ultrasonography is also useful in the evaluation and management of occlusive cerebrovascular disease. Monitoring for microembolic signals enables stratification of stroke risk due to carotid stenosis and can also be used to clarify stroke etiology. TCD ultrasonography can identify patients with exhausted cerebrovascular reserve, and after extracranial-intracranial bypass procedures it can be used to assess adequacy of flow through the graft. Finally, assessment of cerebral autoregulation can be performed using TCD ultrasonography, providing data important to the management of patients with severe traumatic brain injury. As the clinical applications of TCD ultrasonography have expanded over time, so has their importance in the management of neurosurgical patients. Familiarity with this diagnostic tool is crucial for the modern neurological surgeon.

Traumatic cerebrovascular injury: clinical characteristics and illustrative cases

OBJECTIVE

Traumatic cerebrovascular injury (TCVI) is a rare and serious complication of traumatic brain injury (TBI). Various forms of TCVIs have been reported, including occlusions, arteriovenous fistulas, pseudoaneurysms, and transections. They can present at a variety of intervals after TBI and may manifest as sudden episodes, progressive symptoms, and even delayed fatal events. The purpose of this study was to analyze cases of TCVI identified at a single institution and further explore types and characteristics of these complications of TBI in order to improve recognition and treatment of these injuries.

METHODS

The authors performed a retrospective review of cases of TCVI identified at their institution between 2013 and 2016. A total of 5178 patients presented with TBI during this time period, and 42 of these patients qualified for a diagnosis of TCVI and had adequate medical and imaging records for analysis. Data from their cases were analyzed, and 3 illustrative cases are presented in detail.

RESULTS

The most common type of TCVI was arteriovenous fistula (86.4%), followed by pseudoaneurysm (11.9%), occlusion (2.4%), and transection (2.4%). The mortality rate of patients with TCVI was 7.1%.

CONCLUSIONS

The authors describe the clinical characteristics of patients with TCVI and provide data from a series of 42 cases. It is important to recognize TCVI in order to facilitate early diagnosis and treatment.

Second-look strokectomy of cerebral infarction areas in patients with severe herniation

OBJECTIVE

Decompressive craniectomies (DCs) are performed on patients suffering large cerebral infarctions. The efficacy of this procedure has been demonstrated in several trials. In some cases, however, this procedure alone is not sufficient and patients still suffer refractory elevations of intracranial pressure (ICP). The goal of this study was to determine whether resection of infarcted tissue, termed strokectomy, performed as a second-look procedure after DC, improves outcome in selected cases.

METHODS

The authors retrospectively evaluated data of patients who underwent a DC due to a cerebral infarction at their institution from 2009 to 2016, including patients who underwent a strokectomy procedure after DC. Clinical records, imaging data, outcome scores, and neurological symptoms were analyzed, and clinical outcomes and mortality rates in the strokectomy group were compared to those for similar patients in recently published randomized controlled trials.

RESULTS

Of 198 patients who underwent DC due to cerebral infarction, 12 patients underwent strokectomy as a second surgical procedure, with a median National Institutes of Health Stroke Scale (NIHSS) score of 19 for patients with versus 16 for those without secondary strokectomy (p = 0.029). Either refractory increases of ICP > 20 mm Hg or dilated pupils in addition to herniation visible on CT images were triggers for strokectomy surgery. Ten of 12 (83%) patients had infarctions in more than one territory (p < 0.001). After 12 months, 43% of patients had a good outcome according to the modified Rankin Scale (mRS) score (≤ 3). In the subgroup of patients suffering infarctions in more than one vascular territory, functional outcome after 12 months was better (mRS ≤ 3 in 40% of patients in comparison to 9%; p = 0.027). A 1:3 case-control analysis matched to age, side of infarction, sex, and vascular territory confirmed these results (mRS ≤ 3, 42% in comparison to 11%; p = 0.032). Age, NIHSS score on admission, and number of vascular territories involved were identified as risk factors in multivariate analysis (p < 0.05). Patients in the strokectomy group had more infections (p < 0.001). According to these results, the authors developed a scale (Münster Stroke Score, 0-6 points) to predict whether patients might benefit from additional strokectomy. Receiver-operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.86 (p < 0.001). The authors recommend a Münster Stroke Score of ≥ 3 as a cutoff, with a sensitivity of 92% and specificity of 66%, for predicting benefit from strokectomy.

CONCLUSIONS

In this study in comparison to former studies, mortality rates were lower and clinical outcome was comparable to that of previously published trials regarding large cerebral infarctions. Second surgery including strokectomy may help achieve better outcomes, especially in cases of infarction of more than one vascular territory.

Effect of choroidal collateral vessels on de novo hemorrhage in moyamoya disease: analysis of nonhemorrhagic hemispheres in the Japan Adult Moyamoya Trial

OBJECTIVE

Following hemorrhagic stroke in moyamoya disease, de novo intracranial hemorrhage can occur in the previously unaffected nonhemorrhagic hemisphere. In the present analysis the authors intended to determine whether the presence in the nonhemorrhagic hemisphere of choroidal collateral vessels, which have been the focus of attention as a source of bleeding, affects the risk of de novo hemorrhage.

METHODS

The subject of focus of the present cohort study was the nonhemorrhagic hemispheres of adult patients with hemorrhagic moyamoya disease enrolled in the Japan Adult Moyamoya Trial and allocated to the nonsurgical arm. The variable of interest was the presence of choroidal collaterals (also termed choroidal anastomoses), identified with baseline angiography and represented by a connection (anastomosis) between the anterior or posterior choroidal arteries and the medullary arteries. The outcome measure was de novo hemorrhage during the 5-year follow-up period, assessed in all nonhemorrhagic hemispheres. The incidence of de novo hemorrhage in the collateral-positive and -negative groups was compared.

RESULTS

Choroidal collaterals were present in 15 of 36 (41.7%) nonhemorrhagic hemispheres analyzed. The overall annual risk of de novo hemorrhage was 2.0%. Three de novo hemorrhages occurred in the collateral-positive group, whereas no hemorrhage occurred in the collateral-negative group. The annual risk of de novo hemorrhage was significantly higher in the collateral-positive group than in the collateral-negative group (5.8% per year vs 0% per year; p = 0.017). All hemorrhage sites corresponded to the distribution of choroidal collaterals.

CONCLUSIONS

The present preliminary results suggest that the presence of choroidal collaterals affects the risk of de novo hemorrhage in the nonhemorrhagic hemisphere, subject to verification in larger studies. Further studies are needed to determine the optimal treatment strategy for nonhemorrhagic hemispheres and asymptomatic patients.

Incidence, classification, and treatment of angiographically occult intracranial aneurysms found during microsurgical aneurysm clipping of known aneurysms

OBJECTIVE

During the microsurgical clipping of known aneurysms, angiographically occult (AO) aneurysms are sometimes found and treated simultaneously to prevent their growth and protect the patient from future rupture or reoperation. The authors analyzed the incidence, treatment, and outcomes associated with AO aneurysms to determine whether limited surgical exploration around the known aneurysm was safe and justified given the known limitations of diagnostic angiography.

METHODS

An AO aneurysm was defined as a saccular aneurysm detected using the operative microscope during dissection of a known aneurysm, and not detected on preoperative catheter angiography. A prospective database was retrospectively reviewed to identify patients with AO aneurysms treated microsurgically over a 20-year period.

RESULTS

One hundred fifteen AO aneurysms (4.0%) were identified during 2867 distinct craniotomies for aneurysm clipping. The most common locations for AO aneurysms were the middle cerebral artery (60 aneurysms, 54.1%) and the anterior cerebral artery (20 aneurysms, 18.0%). Fifty-six AO aneurysms (50.5%) were located on the same artery as the known saccular aneurysm. Most AO aneurysms (95.5%) were clipped and there was no attributed morbidity. The most common causes of failed angiographic detection were superimposition of a large aneurysm (type 1, 30.6%), a small aneurysm (type 2, 18.9%), or an adjacent normal artery (type 3, 36.9%). Multivariate analysis identified multiple known aneurysms (odds ratio [OR] 3.45, 95% confidence interval [CI] 2.16-5.49, p < 0.0001) and young age (OR 0.981, 95% CI 0.965-0.997, p = 0.0226) as independent predictors of AO aneurysms.

CONCLUSIONS

Meticulous inspection of common aneurysm sites within the surgical field will identify AO aneurysms during microsurgical dissection of another known aneurysm. Simultaneous identification and treatment of these additional undiagnosed aneurysms can spare patients later rupture or reoperation, particularly in those with multiple known aneurysms and a history of subarachnoid hemorrhage. Limited microsurgical exploration around a known aneurysm can be performed safely without additional morbidity.

Hemodynamic analysis of the recipient parasylvian cortical arteries for predicting postoperative hyperperfusion during STA-MCA bypass in adult patients with moyamoya disease

OBJECTIVE

Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is a common approach for treating moyamoya disease (MMD); however, the selection of recipient vessels is still controversial, and its relationship with postoperative cerebral hyperperfusion (CHP) has not been revealed. The aim of the study was to investigate the relationship between the hemodynamic sources of the recipient parasylvian cortical arteries (PSCAs) and the occurrence of postoperative CHP.

METHODS

The authors retrospectively analyzed the clinical data from 68 adult patients (75 hemispheres) with MMD who underwent STA-MCA bypass. Based on their hemodynamic sources from the MCA and non-MCAs, the PSCAs were classified as M-PSCAs and non-M-PSCAs, and their distributional characteristics were studied. Moreover, the patients' demographics, incidence of postoperative CHP, and post- and preoperative relative cerebral blood flow values were examined.

RESULTS

The digital subtraction angiography analysis demonstrated that 40% (30/75) of the recipient PSCAs had no hemodynamic relationship with the MCA. The post- and preoperative relative cerebral blood flow values of the M-PSCA group were significantly higher than those of the non-M-PSCA group (p < 0.001). Multivariate analysis revealed that the hemodynamic source of PSCAs from the MCA was significantly associated with the development of focal (p = 0.003) and symptomatic (p = 0.021) CHP. Twelve (85.7%) of the 14 patients with symptomatic CHP and all 4 (100%) patients with postoperative hemorrhage were from the M-PSCA group.

CONCLUSIONS

This study revealed that direct anastomoses of PSCAs with anterograde hemodynamic sources from the MCA had a high risk of postoperative CHP during STA-MCA bypass in adult patients with MMD.

Mapping language dominance through the lens of the Wada test

The sodium amytal test, or Wada test, named after Juhn Wada, has remained a pillar of presurgical planning and is used to identify the laterality of the dominant language and memory areas in the brain. What is perhaps less well known is that the original intent of the test was to abort seizure activity from an affected hemisphere and also to protect that hemisphere from the effects of electroconvulsive treatment. Some 80 years after Paul Broca described the frontal operculum as an essential area of expressive language and well before the age of MRI, Wada used the test to determine language dominance. The test was later adopted to study hemispheric memory dominance but was met with less consistent success because of the vascular anatomy of the mesial temporal structures. With the advent of functional MRI, the use of the Wada test has narrowed to application in select patients. The concept of selectively inhibiting part of the brain to determine its function, however, remains crucial to understanding brain function. In this review, the authors discuss the rise and fall of the Wada test, an important historical example of the innovation of clinicians in neuroscience.

Long-term patency in cerebral revascularization surgery: an analysis of a consecutive series of 430 bypasses

OBJECTIVE

Large cohort analysis concerning intracerebral bypass patency in patients with long-term follow-up (FU) results is rarely reported in the literature. The authors analyzed the long-term patency of extracranial-to-intracranial (EC-IC) and intracranial-to-intracranial (IC-IC) bypass procedures.

METHODS

All intracranial bypass procedures performed between 1997 and 2017 by a single surgeon were screened. Patients with postoperative imaging (CT angiography, MR angiography, or catheter angiography) were included and grouped into immediate (< 7 days), short-term (7 days-1 year), and long-term (> 1 year) FU groups. Data on patient demographics, bypass type, interposition graft type, bypass indication, and radiological patency were collected and analyzed with univariate and multivariate (adjusted multiple regression) models.

RESULTS

In total, 430 consecutive bypass procedures were performed during the study period (FU time [mean ± SD] 0.9 ± 2.2 years, range 0-17 years). Twelve cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 97%. All bypass occlusions occurred within a week of revascularization. All patients in the short-term FU group (n = 76, mean FU time 0.3 ± 0.3 years) and long-term FU group (n = 89, mean FU time 4.1 ± 3.5 years) had patent bypasses at last FU. Patients who presented with aneurysms had a lower rate of patency than those with moyamoya disease or chronic vessel occlusion (p = 0.029). Low-flow bypasses had a significantly higher patency rate than high-flow bypasses (p = 0.033). In addition, bypasses with one anastomosis site compared to two anastomosis sites showed a significantly higher bypass patency (p = 0.005). No differences were seen in the patency rate among different grafts, single versus bilateral, or between EC-IC and IC-IC bypasses.

CONCLUSIONS

The overall bypass patency of 97% indicates a high likelihood of success with microsurgical revascularization. Surgical indication (ischemia), low-flow bypass, and number of anastomosis (one site) were associated with higher patency rates. EC-IC and IC-IC bypasses have comparable patency rates, supporting the use of intracranial reconstructive techniques. Bypasses that remain patent 1 week postoperatively and have the opportunity to mature have a high likelihood of remaining patent in the long term. In experienced hands, cerebral revascularization is a durable treatment option with high patency rates.

Intrinsic development of choroidal and thalamic collaterals in hemorrhagic-onset moyamoya disease: case-control study of the Japan Adult Moyamoya Trial

OBJECTIVE: This study was performed to identify the angiographic features of hemorrhagic-onset moyamoya disease (MMD) in comparison with those of patients with ischemic-onset MMD. METHODS: This case-control study compared the data set of the Japan Adult Moyamoya (JAM) Trial with the angiographic data of adult patients with ischemic-onset MMD. The authors analyzed angiograms obtained at onset, classifying the collaterals into 3 subtypes: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. They then compared the extent of these collaterals, as indicated by the collateral development grade from 0 to 2 in each subtype, between the JAM Trial group and the ischemic-onset group. They also compared the involvement of the posterior cerebral artery (PCA) and Suzuki's angiographic staging between each group. RESULTS: Among 89 ischemic-onset patients, 103 symptomatic hemispheres in 80 patients were analyzed and compared with 75 hemorrhagic hemispheres from the JAM Trial. The hemorrhagic-onset patients showed a significantly higher proportion of thalamic anastomosis (p = 0.043) and choroidal anastomosis (< 0.001), as indicated by grade 2 in each subtype, compared with ischemic-onset patients. Suzuki's angiographic staging was significantly higher in the hemorrhagic group (< 0.038). There was no difference in the extent of lenticulostriate anastomosis and PCA involvement between the groups. CONCLUSIONS: In adult MMD, the characteristic pattern of the abnormal vascular networks at the base of the brain is different between each onset type. In light of the more prominent development of thalamic and choroidal anastomosis in the JAM Trial group in the present study, development of these collaterals, especially the choroidal collateral extending beyond the lateral ventricle, may play a critical role in hemorrhagic presentation in MMD.Clinical trial registration no. C000000166 (http://www.umin.ac.jp/ctr/index.htm).

Arterial spin-labeling cerebral perfusion changes after revascularization surgery in pediatric moyamoya disease and syndrome

OBJECTIVE

Moyamoya disease is a dynamic cerebrovascular condition that often requires vascular surveillance. Arterial spin labeling (ASL) is an MR perfusion method that is increasingly used for stroke and other various neurovascular pathologies. Unlike perfusion-weighted MRI, ASL uses endogenous water molecules for signal and therefore obviates gadolinium use; and provides direct, not relative, quantitative cerebral blood flow (CBF) measures. Presently, the potential role of ASL for evaluating postoperative pediatric moyamoya patients is relatively unexplored. This study investigated the role for ASL in evaluating cerebral hemodynamic changes in children who underwent revascularization surgery.

METHODS

This retrospective study examined 15 consecutive pediatric patients with moyamoya disease (n = 7) or moyamoya syndrome (n = 8) presenting between 2010 and 2014 who underwent revascularization and in whom 3T ASL was performed pre- and postoperatively. Postoperative MRI at least 3 months after revascularization procedure was used for analysis. Quantitative CBF in various vascular territories was interrogated: anterior, middle, and posterior cerebral arteries, and basal ganglia supplied by the lenticulostriate collaterals, resulting in evaluation of 20 brain regions.

RESULTS

After revascularization, CBF in the high middle cerebral artery territory significantly increased (p = 0.0059), accompanied by a decrease in CBF to the ipsilateral lenticulostriate-supplied basal ganglia (p = 0.0053). No perfusion changes occurred in the remaining cerebral vascular territories after surgery.

CONCLUSIONS

ASL-based quantitative CBF showed improved cerebral perfusion to the middle cerebral artery territory after revascularization in children with both moyamoya syndrome and disease. Reduced perfusion to the basal ganglia might reflect pruning of the lenticulostriate collaterals, potentially from effects of revascularization. ASL can quantitatively evaluate hemodynamic changes in children with moyamoya after revascularization, and it may be a useful adjunct to routine clinical MRI surveillance.

High rebleeding risk associated with choroidal collateral vessels in hemorrhagic moyamoya disease: analysis of a nonsurgical cohort in the Japan Adult Moyamoya Trial

OBJECTIVEChoroidal collateral vessels typical of moyamoya disease have received attention as a potential bleeding source. The authors' previous angiographic cross-sectional analysis suggested a possible association between choroidal collaterals and posterior hemorrhage, indicating a high risk for rebleeding. The present longitudinal analysis is intended to determine whether choroidal collaterals are a predictor of rebleeding in hemorrhagic moyamoya disease.METHODSThe Japan Adult Moyamoya Trial group designed an ancillary cohort study using 5-year follow-up data on 37 patients included in the nonsurgical arm of the original randomized controlled trial and compared the rebleeding rate of those with and those without choroidal collaterals, represented by the connection between the anterior or posterior choroidal arteries and the medullary arteries. An expert panel determined whether a choroidal collateral was present in each patient through the measurement of baseline angiography studies. The rebleeding rate comparison was adjusted for age, diagnosis of hypertension, and involvement of the posterior cerebral artery.RESULTSChoroidal collaterals were present in 21 patients (56.8%). The rebleeding rate was 13.1% per year in the collateral-positive group as compared with 1.3% in the negative group (p = 0.008, log-rank test). The adjusted hazard ratio for rebleeding in the collateral-positive group relative to the negative group remained statistically significant (HR 11.10, 95% CI 1.37-89.91). Radiographic assessment of the collateral-positive group revealed good correspondence between the distribution of collaterals and rebleeding sites.CONCLUSIONSResults of this study suggest that choroidal collaterals are a bleeding source with a high risk for hemorrhagic recurrence and a predictor of rebleeding in hemorrhagic moyamoya disease.

Predictors of neoangiogenesis after indirect revascularization in moyamoya disease: a multicenter retrospective study

OBJECTIVEThe effect of indirect revascularization to improve cerebral perfusion for moyamoya disease (MMD) is based on ingrowth of new vessels into the cortical brain. Preoperative indicators for neoangiogenesis would be helpful to the selection of appropriate procedures for MMD patients but have not yet been investigated. Our study aimed to identify potential predictors for neovascularization after indirect bypass surgery.METHODSThe authors reviewed consecutive cases with complete clinical and radiological documentation of patients who had undergone surgery between December 2010 and January 2018. Patients who were treated with indirect bypass surgery were included. Cerebrovascular characteristics were evaluated by catheter angiography. Neoangiogenesis after indirect bypass was determined as "good" or "poor" based on the Matsushima standard. Univariate and multivariate analyses were performed to identify predictors for neoangiogenesis after indirect bypass. Subgroup analyses by onset type and surgical type were carried out to identify specific predictors for different populations.RESULTSIn total, 231 hemispheres of 209 patients (mean ± SD age 23.06 ± 15.09 years, range 3-61 years) were retrospectively included. In 146 (63.2%) hemispheres, good neoangiogenesis was observed after indirect revascularization. Multivariate analysis showed that the status of ICA moyamoya vessels (p < 0.001, OR [95% CI] 3.242 [2.007-5.236]) is a predictor of favorable neoangiogenesis after indirect bypass surgery, whereas hemorrhagic onset (p < 0.001, OR [95% CI] 0.138 [0.054-0.353]) is a risk factor for poor neoangiogenesis. In addition, younger age was significantly associated with good neovascularization in patients with hemorrhagic onset (p = 0.027, OR [95% CI] 0.893 [0.808-0.987]), whereas age was not a significant predictor for neovascularization in non-hemorrhagic-onset patients (p = 0.955). Hemispheres with good revascularization had lower incidence of rebleeding, lower modified Rankin Scale scores, and more improvement of symptoms during long-term follow-up (p = 0.026, 0.006, and 0.013, respectively).CONCLUSIONSHemorrhagic onset predicts poor neovascularization after indirect bypass surgery for MMD patients. Abundant ICA moyamoya vessels indicate good neoangiogenesis after indirect bypass and vice versa, whereas absent ICA moyamoya vessels predict poor revascularization. Good neovascularization was associated with better long-term outcome. Future studies are needed to further address this issue and clarify the underlying pathophysiological mechanisms.

Ischemic stroke following elective craniotomy in children

OBJECTIVE An ischemic stroke following an elective craniotomy in a child is perceived to be a rare event. However, to date there are few papers on this topic. The purpose of this study was to investigate the occurrence of stroke following elective intracranial surgery at a children’s hospital. METHODS The authors performed a retrospective review of all patients who developed a perioperative stroke following an elective craniotomy from 2010 through 2017. Data were collected using an institutional database that contained demographic, medical, radiological, and outcome variables. RESULTS A total of 1591 elective craniotomies were performed at the authors’ institution during the study period. Of these, 28 (1.8%) were followed by a perioperative stroke. Radiographic diagnosis of the infarction occurred at a median of 1.7 days (range 0–9 days) from the time of surgery, and neurological deficits were apparent within 24 hours of surgery in 18 patients (62.5%). Infarcts tended to occur adjacent to tumor resection sites (86% of cases), and in a unilateral (89%), unifocal (93%), and supratentorial (93%) location. Overall, 11 (39.3%) strokes were due to a perforating artery, 10 (35.7%) were due to a large vessel, 4 (14.3%) were venous, and 3 (10.7%) were related to hypoperfusion or embolic causes. Intraoperative MRI (iMRI) was used in 11 of the 28 cases, and 6 (55%) infarcts were not detected, all of which were deep. CONCLUSIONS The incidence of stroke following an elective craniotomy is low, with nearly all cases (86%) occurring after tumor resection. Perforator infarcts were most common but may be missed on iMRI. ABBREVIATIONS ACA = anterior cerebral artery; AChA = anterior choroidal artery; ACS NSQIP-P = American College of Surgeons National Surgical Quality Improvement Program–Pediatric; CVA = cerebrovascular accident; DWI = diffusion weighted imaging; iMRI = intraoperative MRI; MCA = middle cerebral artery; mRS = modified Rankin Scale; PCA = posterior cerebral artery.

Encephaloduroarteriosynangiosis for pediatric moyamoya disease: long-term follow-up of 100 cases at a single center

OBJECTIVE The object of this study was to summarize the long-term effect of encephaloduroarteriosynangiosis (EDAS) for the treatment of pediatric moyamoya disease (MMD) and to investigate factors influencing the clinical outcomes of EDAS. METHODS Clinical features, angiographic findings, and clinical outcomes were analyzed among MMD patients younger than 18 years who had been treated with EDAS between 2002 and 2007 at the authors' institution. The Kaplan-Meier method was used to estimate stroke risk after EDAS. Predictors of neurological outcome were assessed. RESULTS One hundred fifteen patients were identified. The mean age at symptom onset was 7.3 ± 4.0 years. The incidence of familial MMD was 11.3%. The female/male ratio was 1:1.16. A total of 232 EDAS procedures were performed, and the incidence of postoperative complications was 3%. Postoperative digital subtraction angiography was performed in 54% of the patients, and about 80% of the hemispheres showed good or excellent results. Neovascularization showed significant correlations with delay time (from symptom onset to first operation), Suzuki stage, and preoperative stroke (all p < 0.05). Clinical follow-up was available in 100 patients with a mean follow-up of 124.4 ± 10.5 months. Ten-year cumulative survival was 96.5% after surgery, and the risk of stroke was 0.33%/person-year. An independent life with no significant disability was reported by 92% of the patients. A good outcome correlated with a low Suzuki stage (p = 0.001). Older children and those without preoperative stroke had better clinical outcomes (p < 0.05). CONCLUSIONS On the basis of long-term follow-up data, the authors concluded that EDAS is a safe and effective treatment for pediatric MMD, can reduce the risk of subsequent neurological events, and can improve quality of life. The risk of ischemia-related complications was higher in younger patients, and older children showed better outcomes. Compensation was greater with more prominent cerebral ischemia. The long-term clinical outcome largely depended on the presence and extent of preoperative stroke.

Posterior cerebral artery stenosis and posterior circulation revascularization surgery in pediatric patients with moyamoya disease

OBJECTIVE Some pediatric patients with moyamoya disease (MMD) present with posterior cerebral artery (PCA) stenosis before and after anterior circulation revascularization surgery and require posterior circulation revascularization surgery. This study evaluated the factors associated with PCA stenosis and assessed the efficacy of posterior circulation revascularization surgery, including occipital artery (OA)-PCA bypass, in pediatric patients with MMD. METHODS The presence of PCA stenosis before and after anterior circulation revascularization surgery and its clinical characteristics were investigated in 62 pediatric patients (< 16 years of age) with MMD. RESULTS Twenty-three pediatric patients (37%) with MMD presented with PCA stenosis at the time of the initial diagnosis. A strong correlation between the presence of infarction and PCA stenosis before anterior revascularization was observed (p < 0.001). In addition, progressive PCA stenosis was observed in 12 patients (19.4%) after anterior revascularization. The presence of infarction and a younger age at the time of initial diagnosis were risk factors for progressive PCA stenosis after anterior revascularization (p < 0.001 and p = 0.002, respectively). Posterior circulation revascularization surgery, including OA-PCA bypass, was performed in 9 of the 12 patients with progressive PCA stenosis, all of whom showed symptomatic and/or radiological improvement. CONCLUSIONS PCA stenosis is an important clinical factor related to poor prognosis in pediatric MMD. One should be aware of the possibility of progressive PCA stenosis during the postoperative follow-up period and consider performing posterior circulation revascularization surgery.

Pipeline embolization of posterior circulation aneurysms: a multicenter study of 131 aneurysms

OBJECTIVE

Flow diversion for posterior circulation aneurysms performed using the Pipeline embolization device (PED) constitutes an increasingly common off-label use for otherwise untreatable aneurysms. The safety and efficacy of this treatment modality has not been assessed in a multicenter study.

METHODS

A retrospective review of prospectively maintained databases at 8 academic institutions was performed for the years 2009 to 2016 to identify patients with posterior circulation aneurysms treated with PED placement.

RESULTS

A total of 129 consecutive patients underwent 129 procedures to treat 131 aneurysms; 29 dissecting, 53 fusiform, and 49 saccular lesions were included. At a median follow-up of 11 months, complete and near-complete occlusion was recorded in 78.1%. Dissecting aneurysms had the highest occlusion rate and fusiform the lowest. Major complications were most frequent in fusiform aneurysms, whereas minor complications occurred most commonly in saccular aneurysms. In patients with saccular aneurysms, clopidogrel responders had a lower complication rate than did clopidogrel nonresponders. The majority of dissecting aneurysms were treated in the immediate or acute phase following subarachnoid hemorrhage, a circumstance that contributed to the highest mortality rate in those aneurysms.

CONCLUSIONS

In the largest series to date, fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders.

Endoscopic endonasal transoculomotor triangle approach for adenomas invading the parapeduncular space: surgical anatomy, technical nuances, and case series

OBJECTIVEPituitary adenomas may extend into the parapeduncular space by invading through the roof of the cavernous sinus. Currently, a transcranial approach is the preferred choice, with or without the combination of an endonasal approach. In this paper the authors present a novel surgical approach that takes advantage of the natural corridor provided by the tumor to further open the oculomotor triangle and resect tumor extension into the parapeduncular space.METHODSSix injected specimens were used to demonstrate in detail the surgical anatomy related to the approach. Four cases in which the proposed approach was used were retrospectively reviewed.RESULTSFrom a technical perspective, the first step involves accessing the superior compartment of the cavernous sinus. The interclinoid ligament should be identified and the dura forming the oculomotor triangle exposed. The oculomotor dural opening may be then extended posteriorly toward the posterior petroclinoidal ligament and inferolaterally toward the anterior petroclinoidal ligament. The oculomotor nerve should then be identified; in this series it was displaced superomedially in all 4 cases. The posterior communicating artery should also be identified to avoid its injury. In all 4 cases, the tumor invading the parapeduncular space was completely removed. There were no vascular injuries and only 1 patient had a partial oculomotor nerve palsy that completely resolved in 2 weeks.CONCLUSIONSThe endoscopic endonasal transoculomotor approach is an original alternative for removal of tumor extension into the parapeduncular space in a single procedure. The surgical corridor is increased by opening the dura of the oculomotor triangle and by working below and lateral to the cisternal segment of the oculomotor nerve.

Adenosine-induced cardiac standstill for endovascular treatment of pediatric vein of Galen malformations

Vein of Galen malformations are congenital high-flow vascular malformations that often present with heart failure, hydrocephalus, developmental delay, and intracranial hemorrhage. Because open surgical treatment is associated with high morbidity and mortality, endovascular embolization is increasingly becoming the preferred method of intervention. However, embolization of these lesions can be difficult because of their high-flow nature. The use of adenosine-induced cardiac standstill for treatment of vein of Galen malformations has not been previously described in neonates. The authors describe 3 treatments in 2 patients that demonstrate that the use of adenosine is well tolerated and allows safe transarterial embolization of high-flow vein of Galen malformations in the pediatric population.

Multimodal treatment approach in a patient with multiple intracranial myxomatous aneurysms

The most common primary cardiac tumor is myxoma, typically originating in the left atrium. Emboli to the central nervous system can cause cerebral infarction or, rarely, seed tumor growth within vessel walls, causing myxomatous aneurysms. Fewer than 60 myxomatous aneurysms have been reported, including 2 cases in children. Here, the authors describe 2 different growing myxomatous aneurysms in a child successfully managed using a combined multidisciplinary approach. A 12-year-old boy developed a sudden headache, diplopia, gait instability, and speech difficulty. Magnetic resonance imaging revealed a left parietal hemorrhage and multifocal cerebral infarction, suspicious for an embolic etiology. A cardiac myxoma was identified in the left atrium and resected. Follow-up cranial vasculature imaging demonstrated multiple intracranial myxomatous aneurysms. These lesions were followed up, and serial imaging identified marked growth of 2 of them (right occipital and left parietal), prompting invasive intervention. The deep occipital lesion was better suited to endovascular treatment, while the superficial parietal lesion was amenable to resection. The patient underwent embolization of an enlarging fusiform aneurysm of the distal right posterior cerebral artery, followed by a left parietal craniotomy for a lesion of the distal left middle cerebral artery. Both procedures were performed without complications and achieved successful obliteration of the lesions, as confirmed by catheter angiography at the 30-month follow-up. To the authors' knowledge, this report illustrates the first combined endovascular and open surgical treatment of 2 myxomatous aneurysms in a single patient. While acknowledging the rarity of this condition, this report illustrates the clinical manifestations and treatment challenges posed by myxoma and details a successful strategy that could be employed in similar scenarios.

Flow diversion of a recurrent, iatrogenic basilar tip aneurysm in a pediatric patient: case report

Endoscopic third ventriculostomy (ETV) is a common treatment for noncommunicating hydrocephalus. Although rare, vascular injury and traumatic pseudoaneurysm development during ETV have been reported. The authors present the case of a 13-year-old boy who underwent repeat ETV (rETV) for shunt and ETV failure, and who suffered an intraoperative subarachnoid hemorrhage due to iatrogenic injury to the basilar tip, with subsequent development of a pseudoaneurysm. Despite initial primary coil embolization, the aneurysm recurred and was definitively treated with flow diversion. In this report, the authors review complication rates associated with ETV and rETV as well as the emerging use of flow diversion and its applications in vessel reconstruction within the pediatric population.

The V3 segment of the vertebral artery as a robust donor for intracranial-to-intracranial interpositional bypasses: technique and application in 5 patients

The V₃ segment of the vertebral artery (VA) has been studied in various clinical scenarios, such as in tumors of the craniovertebral junction and dissecting aneurysms. However, its use as a donor artery in cerebral revascularization procedures has not been extensively studied. In this report, the authors summarize their clinical experience in cerebral revascularization procedures using the V₃ segment as a donor. A brief anatomical description of the relevant techniques is also provided.

Revascularization of the upper posterior circulation with the anterior temporal artery: an anatomical feasibility study

OBJECTIVE In various disease processes, including unclippable aneurysms, a bypass to the upper posterior circulation (UPC) including the superior cerebellar artery (SCA) and posterior cerebral artery (PCA) may be needed. Various revascularization options exist, but the role of intracranial (IC) donors has not been scrutinized. The objective of this study was to evaluate the anatomical feasibility of utilizing the anterior temporal artery (ATA) for revascularization of the UPC. METHODS ATA-SCA and ATA-PCA bypasses were performed on 14 cadaver specimens. After performing an orbitozygomatic craniotomy and opening the basal cisterns, the ATA was divided at the M₃-M₄ junction and mobilized to the crural cistern to complete an end-to-side bypass to the SCA and PCA. The length of the recipient artery between the anastomosis and origin was measured. RESULTS Seventeen ATAs were found. Successful anastomosis was performed in 14 (82%) of the ATAs. The anastomosis point on the PCA was 14.2 mm from its origin on the basilar artery. The SCA anastomosis point was 10.1 mm from its origin. Three ATAs did not reach the UPC region due to a common opercular origin with the middle temporal artery. The ATA-SCA bypass was also applied to the management of an incompletely coiled SCA aneurysm. CONCLUSIONS The ATA is a promising IC donor for UPC revascularization. The ATA is exposed en route to the proximal SCA and PCA through the pterional-orbitozygomatic approach. Also, the end-to-side anastomosis provides an efficient and straightforward bypass without the need to harvest a graft or perform multiple or difficult anastomoses.

Pediatric abusive head trauma and stroke

OBJECTIVE Despite established risk factors, abusive head trauma (AHT) continues to plague our communities. Cerebrovascular accident (CVA), depicted as areas of hypodensity on CT scans or diffusion restriction on MR images, is a well-known consequence of AHT, but its etiology remains elusive. The authors hypothesize that a CVA, in isolation or in conjunction with other intracranial injuries, compounds the severity of a child's injury, which in turn leads to greater health care utilization, including surgical services, and an increased risk of death. METHODS The authors conducted a retrospective observational study to evaluate data obtained in all children with AHT who presented to Le Bonheur Children's Hospital (LBCH) from January 2009 through August 2016. Demographic, hospital course, radiological, cost, and readmission information was collected. Children with one or more CVA were compared with those without a CVA. RESULTS The authors identified 282 children with AHT, of whom 79 (28%) had one or more CVA. Compared with individuals without a CVA, children with a stroke were of similar overall age (6 months), sex (61% male), and race (56% African-American) and had similar insurance status (81% public). Just under half of all children with a stroke (38/79, 48%) were between 1-6 months of age. Thirty-five stroke patients (44%) had a Grade II injury, and 44 (56%) had a Grade III injury. The majority of stroke cases were bilateral (78%), multifocal (85%), associated with an overlying subdural hematoma (86%), and were watershed/hypoperfusion in morphology (73%). Thirty-six children (46%) had a hemispheric stroke. There were a total of 48 neurosurgical procedures performed on 28 stroke patients. Overall median hospital length of stay (11 vs 3 days), total hospital charges ($13.8 vs $6.6 million), and mean charges per patient ($174,700 vs $32,500) were significantly higher in the stroke cohort as a whole, as well as by injury grade (II and III). Twenty children in the stroke cohort (25%) died as a direct result of their AHT, whereas only 2 children in the nonstroke cohort died (1%). There was a 30% readmission rate within the first 180-day postinjury period for patients in the stroke cohort, and of these, approximately 50% required additional neurosurgical intervention(s). CONCLUSIONS One or more strokes in a child with AHT indicate a particularly severe injury. These children have longer hospital stays, greater hospital charges, and a greater likelihood of needing a neurosurgical intervention (i.e., bedside procedure or surgery). Stroke is such an important predictor of health care utilization and outcome that it warrants a subcategory for both Grade II and Grade III injuries. It should be noted that the word "stroke" or "CVA" should not automatically imply arterial compromise in this population.

Contralateral posterior interhemispheric approach to deep medial parietooccipital vascular malformations: surgical technique and results

OBJECTIVE Deep medial parietooccipital arteriovenous malformations (AVMs) and cerebral cavernous malformations (CCMs) are traditionally resected through an ipsilateral posterior interhemispheric approach (IPIA), which creates a deep, perpendicular perspective with limited access to the lateral margins of the lesion. The contralateral posterior interhemispheric approach (CPIA) flips the positioning, with the midline positioned horizontally for retraction due to gravity, but with the AVM on the upper side and the approach from the contralateral, lower side. The aim of this paper was to analyze whether the perpendicular angle of attack that is used in IPIA would convert to a parallel angle of attack with the CPIA, with less retraction, improved working angles, and no significant increase in risk. METHODS A retrospective review of pre- and postoperative clinical and radiographic data was performed in 8 patients who underwent a CPIA. RESULTS Three AVMs and 5 CCMs were resected using the CPIA, with an average nidus size of 2.3 cm and CCM diameter of 1.7 cm. All lesions were resected completely, as confirmed on postoperative catheter angiography or MRI. All patients had good neurological outcomes, with either stable or improved modified Rankin Scale scores at last follow-up. CONCLUSIONS The CPIA is a safe alternative approach to the IPIA for deep medial parietooccipital vascular malformations that extend 2 cm or more off the midline. Contralaterality and retraction due to gravity optimize the interhemispheric corridor, the surgical trajectory to the lesion, and the visualization of the lateral margin, without resection or retraction of adjacent normal cortex. Although the falx is a physical barrier to accessing the lesion, it stabilizes the ipsilateral hemisphere while gravity delivers the dissected lesion through the transfalcine window. Patient positioning, CSF drainage, venous preservation, and meticulous dissection of the deep margins are critical to the safety of this approach.

De novo giant posterior cerebral artery aneurysm developing 25 years after basilar bifurcation aneurysm treatment using a Drake tourniquet: case report and implications for aneurysm follow-up

The objective of this paper was to report a rare complication of basilar artery (BA) tourniquet treatment of a giant basilar tip aneurysm, and to discuss possible causes for the formation of a de novo giant posterior cerebral artery (PCA) aneurysm. A 34-year-old woman underwent satisfactory treatment of a ruptured giant basilar bifurcation aneurysm by BA ligation (Drake tourniquet) in 1985. She presented 25 years later with a new aneurysm in the left PCA, successfully treated by coil embolization. To the authors' knowledge, this is the first case of de novo aneurysm formation on a PCA, and the first de novo aneurysm reported as a complication of BA ligation therapy by Drake tourniquet. Long-term follow-up is necessary in patients with treated cerebral aneurysms, particularly those occurring in young patients, those with multiple aneurysms, those with complex posterior circulation aneurysms, and those undergoing flow diversion or flow-altering therapies.

Pathophysiological consideration of medullary streaks on FLAIR imaging in pediatric moyamoya disease

OBJECTIVE Medullary streaks detected on fluid-attenuated inversion recovery (FLAIR) imaging have been considered to be reflected ischemic regions in pediatric moyamoya disease. The purpose of this study was to evaluate these medullary streaks both clinically and radiologically and to discuss associated pathophysiological concerns. METHODS The authors retrospectively reviewed data from 14 consecutive pediatric patients with moyamoya disease treated between April 2009 and June 2016. Clinical and radiological features and postoperative imaging changes were analyzed. In 4 patients, hyperintense medullary streaks on FLAIR imaging (HMSF) at the level of the centrum semiovale were detected. RESULTS The HMSF were coincident with hyperintense medullary streaks on a T2-weighted image, though they were not completely coincident with the vasculature on either a T2*-weighted image or contrast-enhanced CT. Analysis revealed significantly higher values in terms of MR angiography scores, number of flow voids of the basal ganglia, and the presence of the medullary artery in the group with HMSF than in those without. In contrast, the presence of white matter damage was significantly less frequent in the HMSF group. All HMSF disappeared after surgery, and the mean apparent diffusion coefficient at the same level was significantly reduced postoperatively. CONCLUSIONS Although HMSF should be associated with collateral circulation in moyamoya disease, other factors may be involved, including stagnated cerebrospinal fluid or vasogenic edema that is relevant to the impaired state of the white matter. Findings in this study provide insight into the pathophysiological basis of the perivascular space in moyamoya disease.

Flow diverter devices in ruptured intracranial aneurysms: a single-center experience

OBJECTIVE In this single-center series, the authors retrospectively evaluated the effectiveness, safety, and midterm follow-up results of ruptured aneurysms treated by implantation of a flow diverter device (FDD). METHODS The records of 17 patients (12 females, 5 males, average World Federation of Neurosurgical Societies score = 2.9) who presented with subarachnoid hemorrhage (SAH) due to the rupture of an intracranial aneurysm treated with an FDD were retrospectively reviewed. Of 17 ruptured aneurysms, 8 were blood blister-like aneurysms and the remaining 9 were dissecting aneurysms. The mean delay between SAH and treatment was 4.2 days. Intraprocedural and periprocedural morbidity and mortality were recorded. Clinical and angiographic follow-up evaluations were conducted between 6 and 12 months after the procedure. RESULTS None of the ruptured aneurysms re-bled after endovascular treatment. The overall mortality rate was 12% (2/17), involving 2 patients who died after a few days because of complications of SAH. The overall morbidity rate was 12%: 1 patient experienced intraparenchymal bleeding during the repositioning of external ventricular drainage, and 1 patient with a posterior inferior cerebellar artery aneurysm developed paraplegia due to a spinal cord infarction after 2 weeks. The angiographic follow-up evaluations showed a complete occlusion of the aneurysm in 12 of 15 surviving patients; of the 3 remaining cases, 1 patient showed a remnant of the aneurysm, 1 patient was retreated due to an enlargement of the aneurysm, and 1 patient was lost at the angiographic follow-up. CONCLUSIONS FDDs can be used in patients with ruptured aneurysms, where conventional neurosurgical or endovascular treatments can be challenging.

Severe cerebral edema following nivolumab treatment for pediatric glioblastoma: case report

Nivolumab is an immune checkpoint inhibitor (ICI) currently undergoing Phase III clinical trials for the treatment of glioblastoma. The authors present the case of a 10-year-old girl with glioblastoma treated with nivolumab under compassionate-use guidelines. After the first dose of nivolumab the patient developed hemiparesis, cerebral edema, and significant midline shift due to severe tumor necrosis. She was managed using intravenous dexamethasone and discharged on a dexamethasone taper. The patient's condition rapidly deteriorated after the second dose of nivolumab, demonstrating hemiplegia, seizures, and eventually unresponsiveness with a fixed and dilated left pupil. Computed tomography of her brain revealed malignant cerebral edema requiring emergency decompressive hemicraniectomy. Repeat imaging demonstrated increased size of the lesion, reflecting immune-mediated inflammation and tumor necrosis. The patient remained densely hemiplegic, but became progressively more interactive and was ultimately extubated. She resumed nivolumab several weeks later, but again her condition deteriorated with headache, vomiting, swelling at the craniectomy site, and limited right-sided facial movement following the sixth dose. MRI demonstrated severe midline shift and uncal herniation despite her craniectomy. Her condition gradually declined, and she died several days later under "do not resuscitate/do not intubate" orders. To the authors' knowledge, this represents the first case of malignant cerebral edema requiring operative intervention following nivolumab treatment for glioblastoma in a pediatric patient.

Characteristics of infarction after encephaloduroarteriosynangiosis in young patients with moyamoya disease

OBJECTIVE Young patients with moyamoya disease can exhibit infarction after revascularization surgery. This analysis of the characteristics of infarction after encephaloduroarteriosynangiosis (EDAS) in young patients with moyamoya disease was undertaken in an effort to elucidate the infarction mechanism. METHODS The authors retrospectively collected clinical information and reviewed pre- and postoperative MRI studies from cases involving patients younger than 18 years who underwent EDAS for the treatment of moyamoya disease between January 2012 and February 2015. Infarction patterns were categorized into watershed, territorial, or mixed pattern. The Wilcoxon rank sum test, chi-square test, and Fisher exact test were used to compare the clinical and imaging variables between patient groups. The characteristics of patients with and without postoperative infarction were compared using univariate and multivariate analysis. The cumulative proportion of patients without postoperative infarction according to operation stage was calculated using the Kaplan-Meier method and the resulting curves were compared using the log-rank test. RESULTS In 100 patients, 171 EDAS procedures had been performed. There were 38 cases of preoperative infarction in 35 patients and 20 cases of postoperative infarction in 13 patients. Territorial infarction was more frequent in the postoperative infarction group than in the preoperative infarction group (55.0% vs 37.8%, p = 0.037). Infarction was more common on the bilateral or contralateral side of the operation after first-stage EDAS (9 [75.0%] of 12 infarctions) than in the second-stage operation (2 [25.0%] of 8 infarctions), but the difference was not statistically significant (p = 0.068). The frequency of postoperative infarction was not significantly different depending on the stage of the operation (p = 0.694). CONCLUSIONS An acute infarction pattern after EDAS was more frequently territorial, suggesting an underlying occlusive mechanism. Operation stage did not affect the rate of postoperative infarction occurrence.

Aneurysms with persistent patency after treatment with the Pipeline Embolization Device

The Pipeline Embolization Device (PED) was approved for the treatment of intracranial aneurysms from the petrous to the superior hypophyseal segment of the internal carotid artery. However, since its approval, its use for treatment of intracranial aneurysms in other locations and non-sidewall aneurysms has grown tremendously. The authors report on a cohort of 15 patients with 16 cerebral aneurysms that incorporated an end vessel with no significant distal collaterals, which were treated with the PED. The cohort includes 7 posterior communicating artery aneurysms, 5 ophthalmic artery aneurysms, 1 superior cerebellar artery aneurysm, 1 anterior inferior cerebellar artery aneurysm, and 2 middle cerebral artery aneurysms. None of the aneurysms achieved significant occlusion at the last follow-up evaluation (mean 24 months). Based on these observations, the authors do not recommend the use of flow diverters for the treatment of this subset of cerebral aneurysms.

Is less always better? Keyhole and standard subtemporal approaches: evaluation of temporal lobe retraction and surgical volume with and without zygomatic osteotomy in a cadaveric model

OBJECTIVE The subtemporal approach is one of the surgical routes used to reach the interpeduncular fossa. Keyhole subtemporal approaches and zygomatic arch osteotomy have been proposed in an effort to decrease the amount of temporal lobe retraction. However, the effects of these modified subtemporal approaches on temporal lobe retraction have never been objectively validated. METHODS A keyhole and a classic subtemporal craniotomy were executed in 4 fresh-frozen silicone-injected cadaver heads. The target was defined as the area bordered by the superior cerebellar artery, the anterior clinoid process, supraclinoid internal carotid artery, and the posterior cerebral artery. Once the target was fully visualized, the authors evaluated the amount of temporal lobe retraction by measuring the distance between the base of the middle fossa and the temporal lobe. In addition, the volume of the surgical and anatomical corridors was assessed as well as the surgical maneuverability using navigation and 3D moldings. The same evaluation was conducted after a zygomatic osteotomy was added to the two approaches. RESULTS Temporal lobe retraction was the same in the two approaches evaluated while the surgical corridor and the maneuverability were all greater in the classic subtemporal approach. CONCLUSIONS The zygomatic arch osteotomy facilitates the maneuverability and the surgical volume in both approaches, but the temporal lobe retraction benefit is confined to the lateral part of the middle fossa skull base and does not result in the retraction necessary to expose the selected target.

Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere

The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

RNF213 as the major susceptibility gene for Chinese patients with moyamoya disease and its clinical relevance

OBJECTIVE Moyamoya disease (MMD) is a rare, genetically heterogeneous cerebrovascular disease. The authors conducted a genetic study of really interesting new gene (RING) finger protein 213 ( RNF213); actin alpha 2 ( ACTA2); BRCA1/BRCA2-containing complex subunit 3 ( BRCC3); and guanylate cyclase 1, soluble, alpha 3 ( GUCY1A3) as well as a clinical phenotype analysis in Chinese MMD patients to determine whether genetic differences are responsible for the different clinical features that appear in MMD in different ethnicities. METHODS A panel was designed to identify disease-causing mutations in MMD genes and those involved in related disorders ( RNF213, ACTA2, BRCC3, and GUCY1A3). The panel was used to detect disease-causing mutations in 255 Chinese MMD patients. Genotype and allele frequencies were compared between patients and 300 controls. A mutation segregation analysis was performed in 34 families, and genotype-phenotype correlations were made. RESULTS Twenty-seven rare missense variants of RNF213 were identified and were not found in controls. Among them, p.R4810K was identified in 31.4% of patients (80 of 255) with MMD. Significantly higher frequencies of the A allele and G/A genotype of p.R4810K were observed in MMD patients compared with controls (χ² = 104.166, p < 0.000). Twenty-five rare variants were identified in 10.6% of patients (27 of 255) without p.R4810K variants. Segregation analysis supported an association between MMD and 3 variants. No possible disease-causing mutations were identified in ACTA2, BRCC3, or GUCY1A3. Compared with patients without the rare variants in RNF213, the p.R4810K heterozygous patients were younger at diagnosis (25 vs 29 years old, p = 0.049) and had more familial cases (24% vs 4.4%, p = 0.000), ischemic cases (81.3% vs 67.5%, p = 0.037), and involvement of the posterior cerebral artery (52% vs 32.5%, p = 0.007). CONCLUSIONS RNF213 is the major susceptibility gene in Chinese MMD patients. The spectrum of rare variants identified in Chinese MMD patients was diverse. Compared to patients without the rare variants in RNF213, the p.R4810K heterozygous patients exhibited different clinical features.

Endovascular treatment of posterior cerebral artery aneurysms: a single center's experience of 55 cases

OBJECTIVE Aneurysms of the posterior cerebral artery (PCA) are uncommon. To date, a limited number of studies have examined the outcomes of endovascular treatment for PCA aneurysms. The authors' aim in this study is to report their experience with the endovascular treatment of PCA aneurysms. METHODS Between January 2007 and December 2014, 55 patients with 59 PCA aneurysms were treated using the endovascular approach at the authors' institution. Twenty-three patients had 25 saccular aneurysms, and 32 patients had 34 fusiform/dissecting aneurysms. The endovascular modalities included the following: 1) selective occlusion of the aneurysm (n = 22); 2) complete occlusion of the aneurysm and the parent artery (n = 20); 3) parent artery occlusion (n = 6); 4) partial coiling of the aneurysm and the parent artery (n = 5); and 5) occlusion of the dissecting aneurysm sac (n = 2). RESULTS The immediate angiographic results included 45 complete occlusions (82%), 2 nearly complete occlusions (4%), and 8 incomplete occlusions (14%). The mean follow-up period of 21.8 months in 46 patients showed 37 stable results, 6 further thromboses, and 3 recurrences. The final results included 41 complete occlusions (89%), 2 nearly complete occlusions (4%), and 3 incomplete occlusions (7%). Procedure-related complications included the following: 1) rebleeding (n = 1); 2) infarction (n = 4); and 3) perforation (n = 1). There was 1 (1.8%) procedure-related death due to rebleeding, and 2 (3.6%) non-procedure-related deaths due to severe subarachnoid hemorrhage. Clinical outcomes were excellent (Glasgow Outcome Scale 5) in 47 of 49 patients at the long-term follow-up. CONCLUSIONS PCA aneurysms may be effectively treated by different endovascular approaches with favorable clinical and radiological outcomes. However, patients who present with severe SAH still have an overall poor prognosis. Partial coiling of the aneurysm and the parent artery is an attractive alternative treatment for patients who may not tolerate parent artery occlusion. Further study with a larger case series is necessary for validation of the durability and efficacy of this treatment.

Clinical characteristics and outcome of aneurysmal subarachnoid hemorrhage with intracerebral hematoma

OBJECTIVE Intracerebral hematoma (ICH) with subarachnoid hemorrhage (SAH) indicates a unique feature of intracranial aneurysm rupture since the aneurysm is in the subarachnoid space and separated from the brain by pia mater. Broad consensus is lacking regarding the concept that ultra-early treatment improves outcome. The aim of this study is to determine the associative factors for ICH, ascertain the prognostic value of ICH, and investigate how the timing of treatment relates to the outcome of SAH with concurrent ICH. METHODS The study data were pooled from the SAH International Trialists repository. Logistic regression was applied to study the associations of clinical and aneurysm characteristics with ICH. Proportional odds models and dominance analysis were applied to study the effect of ICH on 3-month outcome (Glasgow Outcome Scale) and investigate the effect of time from ictus to treatment on outcome. RESULTS Of the 5362 SAH patients analyzed, 1120 (21%) had concurrent ICH. In order of importance, neurological status, aneurysm location, aneurysm size, and patient ethnicity were significantly associated with ICH. Patients with ICH experienced poorer outcome than those without ICH (OR 1.58; 95% CI 1.37-1.82). Treatment within 6 hours of SAH was associated with poorer outcome than treatment thereafter (adjusted OR 1.67; 95% CI 1.04-2.69). Subgroup analysis with adjustment for ICH volume, location, and midline shift resulted in no association between time from ictus to treatment and outcome (OR 0.99; 95% CI 0.94-1.07). CONCLUSIONS The most important associative factor for ICH is neurological status on admission. The finding regarding the value of ultra-early treatment suggests the need to more robustly reevaluate the concept that hematoma evacuation of an ICH and repair of a ruptured aneurysm within 6 hours of ictus is the most optimal treatment path.

Surgical outcomes following encephaloduroarteriosynangiosis in adult moyamoya disease associated with Type 2 diabetes

OBJECTIVE Debate exists regarding the merits and shortcomings of an indirect bypass procedure for treating adult patients with moyamoya disease (MMD). Considerable variation in neovascularization occurs among different organs in patients with diabetes mellitus. Here, the effect of encephaloduroarteriosynangiosis on MMD associated with Type 2 diabetes mellitus (T2DM) is evaluated. METHODS A retrospective and 1:2 matched case-control study was conducted in moyamoya patients with or without T2DM (n = 180). Postoperative collateral formations were graded according to the Modified Collateral Grading System that originated from the Matsushima Angiographic Stage Classification. Neurological function outcomes before and after the operation were evaluated according to the modified Rankin Scale. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for clinical outcome. RESULTS There was no statistically significant difference in the constituent ratios of initial symptom and preoperative Suzuki stage between patients with and without T2DM. Progression of angiopathy around the circle of Willis was postoperatively observed in bilateral internal carotid arteries in both groups. Patients with T2DM had a higher postoperative Suzuki stage (p < 0.01) and more frequent development of collateral angiogenesis germinating from the external carotid after indirect revascularization procedures in the surgical cerebral hemisphere (82.7% vs 72.2%; p < 0.05). The extent of postoperative collateral formation in patients with diabetes mellitus was significantly higher (p < 0.01). Postoperative clinical improvement in the diabetes group was more common after revascularization procedures (p < 0.05), and the diabetes group had lower modified Rankin Scale scores (p < 0.05) in comparison with the nondiabetes group. Late postoperative stroke and posterior cerebral artery involvement were identified as predictors of unfavorable clinical outcome in both groups, while T2DM was associated with a favorable clinical outcome. CONCLUSIONS Encephaloduroarteriosynangiosis is an efficacious treatment for adult patients with MMD. Patients with T2DM could achieve better collateral circulation and clinical improvement following surgery.

Bilateral pial synangiosis in a child with PHACE syndrome

The acronym PHACE has been used to denote a constellation of abnormalities: posterior fossa anomalies, facial hemangiomas, arterial anomalies, cardiac anomalies, and eye abnormalities. Approximately 30% of patients with large facial hemangiomas have PHACE syndrome, with the vast majority having intracranial arteriopathy. Few reports characterize neurological deterioration from this intracranial arteriopathy, and even fewer report successful treatment thereof. The authors report on a case of a child with PHACE syndrome who presented with an ischemic stroke from a progressive intracranial arteriopathy and describe her successful treatment with bilateral pial synangiosis. An 8-month old girl diagnosed with PHACE syndrome was found to have bilateral internal carotid artery stenosis. Although initially asymptomatic, a few months after diagnosis she suffered a right frontal and parietal stroke. MRI and cerebral angiography investigations demonstrated progressive intracranial arterial stenosis and occlusion. The patient then underwent indirect cerebral revascularization surgery. At 2-year follow-up, she exhibited clinical improvement with persistent speech and motor developmental delay. Follow-up MRI and cerebral angiography showed no new ischemic events and robust extensive vascular collateralization from surgery. PHACE syndrome is an uncommon disease, and affected patients often have cerebral arteriopathy. Although the underlying natural history of cerebral arteriopathy in PHACE remains unclear, cerebral revascularization may represent a potential therapy for symptomatic patients.

Importance of RNF213 polymorphism on clinical features and long-term outcome in moyamoya disease

OBJECT Moyamoya disease (MMD) is an idiopathic cerebrovascular occlusive disorder prevalent in East Asia. In the pathogenesis of MMD, the important role of genetic factors is being elucidated, and RNF213 has recently been identified as a susceptibility gene for MMD. The aim of this retrospective study was to investigate the RNF213 genotype in patients with MMD and to determine their genotype-phenotype associations. METHODS The study involved 165 Korean MMD patients from 155 unrelated families who were diagnosed with MMD at a single center from 1995 to 2013. Their demographic, radiological, and clinical findings were evaluated. Direct sequencing of the major RNF213 single nucleotide polymorphisms was performed. The association of the common RNF213 variant with MMD risk was evaluated using historical controls for comparison. Correlations between RNF213 genotype and phenotype were statistically analyzed. RESULTS The c.14429G>A (p.R4810K) variant was identified in 125 (75.8%) of 165 MMD patients. Most patients (112) were heterozygous, and 13 patients had 2 copies of the c.14429G>A variant. A novel heterozygous variant, c.12086A>G (p.Q4029R), was found in 1 additional patient. The minor allele frequency of the c.14429G>A variant was significantly higher in the MMD group (138 [41.8%] of 330 patients) than in the control group (8 [1.36%] of 588 subjects; p < 0.001). The c.14429G>A (p.R4810K) variant significantly increased the risk of MMD in Korean patients, with an OR of 52.11 (p < 0.001) compared with controls. Moreover, c.14429G>A (p.R4810K) genotypes occurred more frequently in patients with a family history of MMD. The homozygous variant was highly associated with early-onset MMD (age at onset < 5 years), cerebral infarction at diagnosis, and cognitive impairment in long-term outcome. CONCLUSIONS The findings indicate that the c.14429G>A (p.R4810K) allele of RNF213 is strongly associated with Korean patients with MMD. The homozygous c.14429G>A (p.R4810K) variant is particularly related to early-onset MMD, severe symptomatic manifestations at diagnosis, and poor prognosis. This genotypic variant may be a useful biomarker for early-onset MMD or unstable MMD with cerebral infarction, which requires early diagnosis and revascularization treatment.

Anatomy and approaches along the cerebellar-brainstem fissures

OBJECT Fissure dissection is routinely used in the supratentorial region to access deeply situated pathology while minimizing division of neural tissue. Use of fissure dissection is also practical in the posterior fossa. In this study, the microsurgical anatomy of the 3 cerebellar-brainstem fissures (cerebellomesencephalic, cerebellopontine, and cerebellomedullary) and the various procedures exposing these fissures in brainstem surgery were examined. METHODS Seven cadaveric heads were examined with a microsurgical technique and 3 with fiber dissection to clarify the anatomy of the cerebellar-brainstem and adjacent cerebellar fissures, in which the major vessels and neural structures are located. Several approaches directed along the cerebellar surfaces and fissures, including the supracerebellar infratentorial, occipital transtentorial, retrosigmoid, and midline suboccipital approaches, were examined. The 3 heads examined using fiber dissection defined the anatomy of the cerebellar peduncles coursing in the depths of these fissures. RESULTS Dissections directed along the cerebellar-brainstem and cerebellar fissures provided access to the posterior and posterolateral midbrain and upper pons, lateral pons, floor and lateral wall of the fourth ventricle, and dorsal and lateral medulla. CONCLUSIONS Opening the cerebellar-brainstem and adjacent cerebellar fissures provided access to the brainstem surface hidden by the cerebellum, while minimizing division of neural tissue. Most of the major cerebellar arteries, veins, and vital neural structures are located in or near these fissures and can be accessed through them.

Multimodal treatment strategies for complex pediatric cerebral arteriovenous fistulas: contemporary case series at Barrow Neurological Institute

OBJECT Pediatric cerebral arteriovenous fistulas (AVFs) are rare but potentially lethal vascular lesions. Management strategies for these lesions have undergone considerable evolution in the last decade with the advent of new endovascular, surgical, and radiosurgical technologies. This study sought to review current treatment strategies and long-term clinical outcomes at a high-volume cerebrovascular institute. METHODS A retrospective chart review was performed on patients with a diagnosis of cerebral AVF from 1999 to 2012. Patients with carotid-cavernous fistulas, vein of Galen malformations, and age > 18 years were excluded from final analysis. Medical history, surgical and nonsurgical treatment, and clinical outcomes were documented. Pre- and postoperative angiograms were analyzed to assess for obliteration of the fistula. RESULTS Seventeen patients with pial AVFs (29.4%), dural AVFs (64.7%), or mixed pial/dural AVFs (5.9%) were identified. The majority of lesions were paramedian (70.6%) and supratentorial (76.5%). The study population had a mean age of 6.4 years, with a slight male predominance (52.9%), and the most common presenting symptoms were seizures (23.5%), headaches (17.6%), congestive heart failure (11.7%), and enlarging head circumference (11.7%). Among patients who underwent intervention (n = 16), 56.3% were treated with endovascular therapy alone, 6.3% were treated with open surgery alone, and 37.5% required a multimodal approach. Overall, 93.8% of the treated patients received endovascular treatment, 43.8% received open surgery, and 12.5% received radiosurgery. Endovascular embolysates included Onyx (n = 5), N-butyl cyanoacrylate (NBCA; n = 4), or coil embolization (n = 7) with or without balloon assistance (n = 2). Complete angiographic obliteration was achieved in 87.5% at the last follow-up evaluation (mean follow-up 3.1 years). One infant with incomplete AVF obliteration died of congestive heart failure, and 1 patient with complete obliteration died of acute sinus thrombosis, with an overall complication rate of 18.8%. CONCLUSIONS Pediatric cerebral AVFs are challenging neurosurgical lesions. Although advancements in endovascular therapy in the last decade have greatly changed the natural course of this disease, a multidisciplinary approach remains necessary for a large subset of patients. Surgeon experience with a thorough analysis of preoperative imaging is paramount to achieving acceptable clinical outcomes.

Rapid ventricular pacing for a basilar artery pseudoaneurysm in a pediatric patient: case report

Large cerebral aneurysms of the basilar apex are difficult to treat. Recently, endovascular treatment has mitigated much of the morbidity associated with treating these lesions. However, the morphology of aneurysms of the vertebrobasilar system can preclude endovascular treatment. Rapid ventricular pacing (RVP) facilitates open surgical treatment of cerebral aneurysms. It can assist in reducing the pressure of the neck of the aneurysm, allowing safe application of a clip. The authors present a case of a pediatric patient who developed a basilar artery pseudoaneurysm that required surgery. Given the large size of the aneurysm, RVP was performed, allowing the surgeons to dissect the dome of the aneurysm from the surrounding tissue and pontine perforating branches away from the lesion to safely clip the lesion. The patient had an uneventful recovery. To the authors' knowledge, this represents the first known case of RVP to aid in basilar artery clip occlusion in a pediatric patient.

Brainstem arteriovenous malformations: anatomical subtypes, assessment of "occlusion in situ" technique, and microsurgical results

OBJECT

The surgical management of brainstem arteriovenous malformations (AVMs) might benefit from the definition of anatomical subtypes and refinements of resection techniques. Many brainstem AVMs sit extrinsically on pia mater rather than intrinsically in the parenchyma, allowing treatment by occluding feeding arteries circumferentially, interrupting draining veins after arteriovenous shunting is eliminated, and leaving the obliterated nidus behind. The authors report here the largest series of brainstem AVMs to define 6 subtypes, assess this "occlusion in situ" technique, and analyze the microsurgical results.

METHODS

Brainstem AVMs were categorized as 1 of 6 types: anterior midbrain, posterior midbrain, anterior pontine, lateral pontine, anterior medullary, and lateral medullary AVMs. Data from a prospectively maintained AVM registry were reviewed to evaluate multidisciplinary treatment results.

RESULTS

During a 15-year period, the authors treated 29 patients with brainstem AVMs located in the midbrain (1 anterior and 6 posterior), pons (6 anterior and 7 lateral), and medulla (1 anterior and 8 lateral). The nidus was pial in 26 cases and parenchymal in 3 cases. Twenty-three patients (79%) presented with hemorrhage. Brainstem AVMs were either resected (18 patients, 62%) or occluded in situ (11 patients, 38%). All lateral pontine AVMs were resected, and the occlusion in situ rate was highest with anterior pontine AVMs (83%). Angiography confirmed complete obliteration in 26 patients (89.6%). The surgical mortality rate was 6.9%, and the rate of permanent neurological deterioration was 13.8%. At follow-up (mean 1.3 years), good outcomes (modified Rankin Scale [mRS] score ≤ 2) were observed in 18 patients (66.7%) and poor outcomes (mRS score of 3-5) were observed in 9 patients (33.3%). The mRS scores in 21 patients (77.8%) were unchanged or improved. The best outcomes were observed with lateral pontine (100%) and lateral medullary (75%) AVMs, and the rate of worsening/death was greatest with posterior midbrain and anterior pontine AVMs (50% each).

CONCLUSIONS

Brainstem AVMs can be differentiated by their location in the brainstem (midbrain, pons, or medulla) and the surface on which they are based (anterior, posterior, or lateral). Anatomical subtypes can help the neurosurgeon determine how to advise patients, with lateral subtypes being a favorable surgical indication along with extrinsic pial location and hemorrhagic presentation. Most AVMs are dissected with the intention to resect them, and occlusion in situ is reserved for those AVMs that do not separate cleanly from the brainstem, that penetrate into the parenchyma, or are more anterior in location, where it is difficult to visualize and preserve perforating arteries (anterior pontine and lateral medullary AVMs). Although surgical morbidity is considerable, surgery results in a better obliteration rate than nonoperative management and is indicated in highly selected patients with high rerupture risks.

Extent of collateralization predicting symptomatic cerebral vasospasm among pediatric patients: correlations among angiography, transcranial Doppler ultrasonography, and clinical findings

OBJECT

Although the development and prevalence of cerebral vasospasm (CV) has been extensively investigated in adults, little data exist on the development of CV in children. The authors hypothesized that even though children have highly vasoreactive arteries, because of a robust cerebral collateral blood flow, they rarely develop symptomatic CV.

METHODS

The authors retrospectively reviewed their university hospital's neurointerventional database for children (that is, patients ≤ 18 years) who were examined or treated for aneurysmal or traumatic subarachnoid hemorrhage (SAH) during the period 1990-2013. Images from digital subtraction angiography (DSA) were analyzed for the extent of CV and collateralization of the cerebral circulation. Results from transcranial Doppler (TCD) ultrasonography were correlated with those from DSA. Cerebral vasospasm on TCD ultrasonography was defined according to criteria developed for adults. Clinical outcomes of CV were assessed with the pediatric modified Rankin Scale (mRS).

RESULTS

Among 37 children (21 boys and 16 girls ranging in age from 8 months to 18 years) showing symptoms of an aneurysmal SAH (comprising 32 aneurysms and 5 traumatic pseudoaneurysms), 17 (46%) had CV confirmed by DSA; CV was mild in 21% of these children, moderate in 50%, and severe in 29%. Only 3 children exhibited symptomatic CV, all of whom had poor collateralization of cerebral vessels. Among the 14 asymptomatic children, 10 (71%) showed some degree of vessel collateralization. Among 16 children for whom TCD data were available that could be correlated with the DSA findings, 13 (81%) had CV according to TCD criteria. The sensitivity and specificity of TCD ultrasonography for diagnosing CV were 95% and 59%, respectively. The time to CV onset detected by TCD ultrasonography was 5 ± 3 days (range 2-10 days). Twenty-five (68%) of the children had good long-term outcomes (that is, had mRS scores of 0-2).

CONCLUSIONS

Children have a relatively high incidence of angiographically detectable, moderate-to-severe CV. Children rarely develop symptomatic CV and have good long-term outcomes, perhaps due to robust cerebral collateral blood flow. Criteria developed for detecting CV with TCD ultrasonography in adults overestimate the prevalence of CV in children. Larger studies are needed to define TCD ultrasonography-based CV criteria for children.

Frameless neuronavigation based only on 3D digital subtraction angiography using surface-based facial registration

OBJECT

Cerebrovascular lesions can have complicated abnormal anatomy that is not completely characterized by CT or MR angiography. Although 3D rotational angiography provides superior spatial and temporal resolution, catheter angiograms are not easily registered to the patient, limiting the use of these images as a source for neuronavigation. However, 3D digital subtraction angiography (DSA) contains not only vascular anatomy but also facial surface anatomy data. The authors report a novel technique to register 3D DSA images by using only the surface anatomy contained within the data set without having to fuse the DSA image set to other imaging modalities or use fiducial markers.

METHODS

A cadaver model was first created to assess the accuracy of neuronavigation based on 3D DSA images registered by facial surface anatomy. A 3D DSA scan was obtained of a formalin-fixed cadaver head, with acquisitions of mask and contrast runs. The right common carotid artery was injected prior to the contrast run with a 45% contrast solution diluted with water-soluble red liquid latex. One week later, the head was registered to a neuronavigation system loaded with the 3D DSA images acquired earlier using facial surface anatomy. A right pterional craniotomy was performed and 10 different vascular landmarks were identified and measured for accuracy using the neuronavigation system. Neuronavigation based only on 3D DSA was then used to guide an open clipping procedure for a patient who presented with a ruptured distal lenticulostriate aneurysm.

RESULTS

The accuracy of the measurements for the cadaver model was 0.71 ± 0.25 mm (mean ± SE), which is superior to the 1.8-5 mm reported for neuronavigation. The 3D DSA-based navigation-assisted surgery for the distal lenticulostriate aneurysm aided in localization, resulting in a small craniotomy and minimal brain dissection.

CONCLUSIONS

This is the first example of frameless neuronavigation based on 3D catheter angiography registered by only the surface anatomy data contained within the 3D DSA image set. This is an easily applied technique that is beneficial for accurately locating vascular pathological entities and reducing the dissection burden of vascular lesions.

Radiographic absence of the posterior communicating arteries and the prediction of cognitive dysfunction after carotid endarterectomy

OBJECT

Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD.

METHODS

Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA.

RESULTS

Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43-64.92, p = 0.02).

CONCLUSIONS

The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 ( http://www.clinicaltrials.gov ).

Surgical management of medically refractory epilepsy due to early childhood stroke

OBJECT.: The risk of developing epilepsy after perinatal stroke, hypoxic/ischemic injury, and intracerebral hemorrhage is significant, and seizures may become medically refractory in approximately 25% of these patients. Surgical management can be difficult due to multilobar or bilateral cortical injury, nonfocal or poorly lateralizing video electroencephalography (EEG) findings, and limited functional reserve. In this study the authors describe the surgical approaches, seizure outcomes, and complications in patients with epilepsy due to vascular etiologies in the perinatal period and early infancy.

METHODS

The records were analyzed of 19 consecutive children and adults with medically refractory epilepsy and evidence of perinatal arterial branch occlusions, hypoxic/ischemic insult, or hemorrhagic strokes, who underwent surgery at the Comprehensive Epilepsy Center of Beth Israel Medical Center and St. Luke's-Roosevelt Hospital Center. Preoperative findings including MRI, video EEG, functional MRI, and neuropsychological testing were analyzed. The majority of patients underwent staged operations with invasive mapping, and all patients had either extra- or intraoperative functional mapping.

RESULTS

In 7 patients with large porencephalic cysts due to major arterial branch occlusions, periinsular functional hemispherotomy was performed in 4 children, and in 3 patients, multilobar resections/disconnections were performed, with 1 patient undergoing additional resections 3 years after initial surgery due to recurrence of seizures. All of these patients have been seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 15-77 months). Another 8 patients had intervascular border-zone ischemic infarcts and encephalomalacia, and in this cohort 2 hemispherotomies, 5 multilobar resections/disconnections, and 1 focal cortical resection were performed. Seven of these patients remain seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 9-94 months), and 1 patient suffered a single seizure after 2.5 years of seizure freedom (Engel Class IB, 33-month follow-up). In the final 4 patients with vascular malformation-associated hemorrhagic or ischemic infarction in the perinatal period, a hemispherotomy was performed in 1 case, multilobar resections in 2 cases, and in 1 patient a partial temporal lobectomy was performed, followed 6 months later by a complete temporal and occipital lobectomy due to ongoing seizures. All of these patients have had seizure freedom (Engel Class IA) with a mean follow-up of 4.5 years (range 10-80 months). Complications included transient monoparesis or hemiparesis in 3 patients, transient mutism in 1 patient, infection in 1 patient, and a single case of permanent distal lower-extremity weakness. Transient mood disorders (depression and anxiety) were observed in 2 patients and required medical/therapeutic intervention.

CONCLUSIONS

Epilepsy surgery is effective in controlling medically intractable seizures after perinatal vascular insults. Seizure foci tend to be widespread and rarely limited to the area of injury identified through neuroimaging, with invasive monitoring directing multilobar resections in many cases. Long-term functional outcomes have been good in these patients, with significant improvements in independence, quality of life, cognitive development, and motor skills, despite transient postoperative monoparesis or hemiparesis and occasional mood disorders.

Surgery for a giant arteriovenous malformation without motor deterioration: preoperative transcranial magnetic stimulation in a non-cooperative patient

Transcranial magnetic stimulation (TMS) is a noninvasive activation method that is increasingly used for motor mapping. Preoperative functional mapping in vascular surgery is not routinely performed; however, in cases of high-grade arteriovenous malformations (AVMs), it could play a role in preoperative decision making. A 16-year-old male was suffering from a giant, right-sided insular, Spetzler-Martin Grade V AVM. This patient's history included 3 hemorrhagic strokes in the past 3 years, resulting in Medical Research Council Grade 2-3 (proximal) and 2-4 (distal) paresis of the left side of the body and hydrocephalus requiring a ventriculoperitoneal shunt. Preoperative TMS showed absent contralateral innervation of the remaining left-sided motor functions. Subsequently, the AVM was completely resected without any postoperative increase of the left-sided paresis. This case shows that TMS can support decision making in AVM treatment by mapping motor functions.

Revascularization and pediatric aneurysm surgery

OBJECT

Aneurysms are relatively rare in the pediatric population and tend to include a greater proportion of large and giant lesions. A subset of these large and giant aneurysms are not amenable to direct surgical clipping and require complex treatment strategies and revascularization techniques. There are limited data available on the management of these lesions in the pediatric population. This study was undertaken to evaluate the outcome of treatment of large and giant aneurysms that required microsurgical revascularization and vessel sacrifice in this population.

METHODS

The authors retrospectively identified all cases in which pediatric patients (age < 18 years) with aneurysms were treated using cerebral revascularization in combination with other treatment modalities at their institution between 1989 and 2013.

RESULTS

The authors identified 27 consecutive patients (19 male and 8 female) with 29 aneurysms. The mean age of the patients at the time of treatment was 11.5 years (median 13 years, range 1-17 years). Five patients presented with subarachnoid hemorrhage, 11 with symptoms related to mass effect, 2 with stroke, and 3 with seizures; in 6 cases, the aneurysms were incidental findings. Aneurysms were located along the internal carotid artery (n = 7), posterior cerebral artery (PCA) (n = 2), anterior cerebral artery (n = 2), middle cerebral artery (MCA) (n = 14), basilar artery (n = 2), vertebral artery (n = 1), and at the vertebrobasilar junction (n = 1). Thirteen were giant aneurysms (45%). The majority of the aneurysms were fusiform (n = 19, 66%), followed by saccular (n = 10, 34%). Three cases were previously treated using microsurgery (n = 2) or an endovascular procedure (n = 1). A total of 28 revascularization procedures were performed, including superficial temporal artery (STA) to MCA (n = 6), STA to PCA (n = 1), occipital artery to PCA (n = 1), extracranial-intracranial (EC-IC) bypass using radial artery graft (n = 3), EC-IC using a saphenous vein graft (n = 7), STA onlay (n = 3), end-to-end anastomosis (n = 1), and in situ bypasses (n = 6). Perioperative stroke occurred in 4 patients, but only one remained dependent (Glasgow Outcome Scale [GOS] score 3). At a mean clinical follow-up of 46 months (median 14 months, range 1-232 months), 26 patients had a good outcome (GOS score 4 or 5). There were no deaths. Five patients had documented occlusion of the bypass graft. The majority of aneurysms (n = 24) were obliterated at last follow-up. There was a single case of a residual aneurysm and one case of recurrence. Angiographic follow-up was unavailable in 3 cases.

CONCLUSIONS

Cerebral revascularization remains an essential tool in the treatment of complex cerebral aneurysms in children.