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Reactive oxygen species and other free radicals cause oxidative stress which is the underlying pathogenesis of cellular injury in various neurological diseases. Molecular hydrogen therapy with its unique biological property of selectively scavenging pathological free radicals has demonstrated therapeutic potential in innumerable animal studies and some clinical trials. These studies have implicated several cellular pathways affected by hydrogen therapy in explaining its anti-inflammatory and antioxidative effects. This article reviews relevant animal and clinical studies that demonstrate neuroprotective effects of hydrogen therapy in stroke, neurodegenerative diseases, neurotrauma, and global brain injury.

We present the case of a 16-week pregnant 19-year-old female who presented with hemiplegia due to a ruptured right frontal pial arteriovenous fistula (PAVF). She was also found to have an unruptured right temporal PAVF and a family history of brain hemorrhage. The patient was managed with Onyx embolization of the ruptured fistula, followed by surgical excision and hematoma evacuation. At 35 weeks gestation, she underwent cesarean section to prevent rupture of the second fistula in the setting of peripartum hypervolemia and increasing headaches. The child was delivered healthy. Subsequently, the right temporal AV fistula, supplied by a middle cerebral artery and posterior cerebral artery branch, underwent staged embolization resulting in complete occlusion. The patient recovered to a modified Rankin score of two, with a left foot drop as only persistent significant motor deficit.

The pretemporal transcavernous approach (PTA) provides optimal exposure and access to the basilar artery (BA); however, the PTA can be invasive when vital neurovascular structures are mobilized. The goal of this study was to evaluate mobilization strategies to tailor approaches to the BA. After an orbitozygomatic craniotomy, 10 sides of 5 cadaveric heads were used to assess the surgical access to the BA via the opticocarotid triangle (OCT), carotid-oculomotor triangle (COT), and oculomotor-tentorial triangle (OTT). Measurements were obtained, and morphometric analyses were performed for natural neurovascular positions and after each stepwise expansion maneuver. An imaginary line connecting the midpoints of the limbus sphenoidale and dorsum sellae was used as a reference to normalize the measurements of BA exposure and to facilitate the clinical applicability of this technique. In the OCT, the exposed BA segment ranged from − 1 ± 3.9 to + 6 ± 2.0 mm in length in its natural position. In the COT, the accessible BA segment ranged from − 4 ± 2.3 to − 2 ± 3.0 mm in length in its natural position. Via the OTT, the accessible BA segment ranged from − 7 ± 2.6 to − 5 ± 2.8 mm in length in its natural position. In the OCT, COT, and OTT, a posterior clinoidectomy extended the exposure down to − 6 ± 2.7, − 8 ± 2.5, and − 9 ± 2.9 mm, respectively. This study quantitatively evaluated the need for the expansion maneuvers in the PTA to reach BA aneurysms according to the patient’s anatomical characteristics.

Recurrent sequential mechanical thrombectomy for cryptogenic large vessel occlusion (LVO) can lead to excellent clinical outcome. A 68-year-old right-handed male presented with an acute proximal right middle cerebral artery (MCA) ischemic syndrome and underwent successful revascularization by mechanical thrombectomy with normal functional recovery. He was treated with dual antiplatelet therapy for 2 months following discharge, however later discontinued clopidogrel due to side effects. He then developed a recurrent, contralateral MCA occlusion 16 months later and once again received emergent endovascular reperfusion therapy with excellent neurological outcome. He has remained on off-label empiric oral anticoagulation since and has not had recurrent stroke nor evidence of cerebral ischemia. Favorable clinical outcomes can be achieved in patients despite recurrent LVO who underwent emergent mechanical thrombectomy. Optimal antithrombotic secondary stroke prevention strategies following embolic stroke of unknown source remains uncertain as recent evidence does not support rivaroxaban or dabigatran over aspirin. The benefit of apixaban over aspirin for the prevention of recurrent cerebral ischemia is under current investigation.

We describe a case of severe headaches, double vision, and progressive vision loss secondary to a ruptured intracranial cyst (IAC) in a 31-year-old woman with no relevant past medical history. The case is peculiar because drainage of the subdural hygroma led to a minimal improvement in vision with persistent elevated intracranial pressure (ICP). Further exploration revealed transverse sinus stenosis necessitating stenting. Evaluation post-stenting showed marked reduction of ICP and improvement in symptoms. This report underscores the importance of comprehensive work-up and suspicion of multiple underlying etiologies that may be crucial to complete resolution of presenting symptoms in some cases. We provide an overview of the clinical indications and evidence for venous sinus stenting in treating idiopathic intracranial hypertension (IIH).

Introduction Blister type aneurysms are challenging to treat surgically and endovascularly with the ideal treatment approach debated. Recently, endovascular procedures, specifically, flow diversion, gained popularity in treating blister aneurysms; however, the need for dual antiplatelet therapy arouses concern, especially in blister aneurysms with their high risk of intraprocedural rupture that may require further intervention. Cangrelor is a novel intravenous P2Y12 platelet receptor antagonist with reversible binding and rapid onset and offset of action. These characteristics are appealing for use in endovascular procedures and may mitigate some concerns associated with other P2Y12 receptor antagonists. Case Summary This is a 42-year old female who presented with sudden onset of severe headache, nausea, and vomiting. On exam, she was drowsy with no focal neurologic deficits. Initial CT head, CT angiogram, and digital subtraction angiography (DSA) were negative for aneurysm or other vascular pathology. On post bleed day (PBD) 7, repeat DSA demonstrated severe vasospasm and a nonspecific ectatic segment along the distal intracranial internal carotid artery (ICA). On daily angiograms for intraarterial spasmolysis, the ectatic segment remained unchanged until PBD 14, when it began to enlarge and exhibited rapid growth over several days. Management We treated this patient endovascularly using a pipeline flow diversion device. Immediately prior to pipeline placement, in addition to aspirin and heparin, we also began infusing cangrelor, a novel, reversible, intravenous P2Y12 platelet receptor antagonist with rapid onset and offset of action. After the procedure, she transitioned from cangrelor to prasugrel. Our patient tolerated the procedure well, and on post-procedure day 4, she was discharged home on daily prasugrel and aspirin. To date, our patient is doing well clinically, and her pipeline appears patent with no evidence of aneurysm recurrence. Conclusion This is one of the first reports of the use of cangrelor in neuro-endovascular procedures. This is important as cangrelor has the potential for improving the safety of endovascular procedures especially in patients where treatment is associated with high risks of intraprocedural bleeding or other complications that may require further intervention, such as in treatment of blister aneurysms. Disclosures T. Wilson: None. D. Ramanathan: None. J. Dye: None.

Background: It is well known that intracranial aneurysms can be associated to fibromuscular dysplasia (FMD). Nevertheless, it is not clear the best treatment strategy when there is an association of giant symptomatic cavernous carotid aneurysm with extensive cervical internal carotid artery (ICA) FMD. Case Description: We present the case of 63 year-old right-handed female with hypothyroidism, 1 month history of right-sided pulsatile headache and visual disturbances with feeling of fullness sensation and blurry vision. Her neurological exam showed partial right oculomotor nerve palsy with mild ptosis, asymmetric pupils (right 5 mm and left 3mm, both reactive), and mild exotropia, normal visual acuity. Computed tomography angiogram and conventional angiogram showed 2.5 × 2.6 × 2.6 cm non-ruptured aneurysm arising from cavernous segment of the right ICA. She had right hypoplastic posterior communicant artery, and collateral flow through anterior communicant artery during balloon test occlusion and the presence of right cervical ICA FMD. The patient was started on aspirin. After lengthy discussion of treatment options in our neurovascular department, between observations, endovascular treatment with flow diverter device, or high flow bypass, recommendation was to perform high flow bypass and patient consented for the procedure. We performed right-sided pterional trans-sylvian microsurgical approach and right neck dissection at common carotid bifurcation under electrophysiology monitoring (somatosensory evoked potentials and electroencephalography); while vascular surgery department assisted with the radial artery graft harvesting. The radial artery graft was passed through preauricular tunnel, cranially was anastomosed at superior trunk of middle cerebral artery, and caudally at external carotid artery (Video). Intraoperative angiogram showed adequate bypass patency and lack of flow within aneurysm. The patient was extubated postoperatively and discharged home with aspirin in postoperative day 5. Improvement on oculomotor deficit was complete 3 weeks after surgery. Conclusion: Nowadays, endovascular therapy can manage small to large cavernous ICA aneurysms even if associated to FMD, although giant symptomatic cavernous carotid aneurysms impose a different challenge. Here, we present the management for the association of symptomatic giant cavernous ICA aneurysm and cervical ICA FMD with high flow bypass. We consider important to keep the skills in the cerebrovascular neurosurgeon armamentarium for the safe management of these lesions.

Although the majority of meningiomas are slow-growing and benign, atypical and anaplastic meningiomas behave aggressively with a penchant for recurrence. Standard of care includes surgical resection followed by adjuvant radiation in anaplastic and partially resected atypical meningiomas; however, the role of adjuvant radiation for incompletely resected atypical meningiomas remains debated. Despite maximum treatment, atypical, and anaplastic meningiomas have a strong proclivity for recurrence. Accumulating mutations over time, recurrent tumors behave more aggressively and often become refractory or no longer amenable to further surgical resection or radiation. Chemotherapy and other medical therapies are available as salvage treatment once standard options are exhausted; however, efficacy of these agents remains limited. This review discusses the risk factors, classification, and molecular biology of meningiomas as well as the current management strategies, novel therapeutic approaches, and future directions for managing atypical and anaplastic meningiomas.

Radiosurgery is an increasingly popular treatment for trigeminal neuralgia (TN); however, several treatment variables require further study. This meta-analysis was conducted to clarify ambiguity in the literature and optimize treatment parameters.A random-effects proportions meta-analysis using subgroup analysis and meta-regression investigated the association of prescription dose and anatomic target on outcomes in patients with typical TN. The PRISMA guidelines were used. Radiation doses used ranged from 70 to 90 Gy and the anatomic targets were either the root entry zone or a more distal nerve location. Outcome measures were pain at last follow-up and the development of bothersome numbness.Increasing radiation prescription dose was associated with improved outcomes across all analyzed doses (P0.001). Patients treated at a distal trigeminal nerve target had better pain control compared with a root entry zone target (P0.001). Despite a higher median dose, a distal target was independently associated with improved pain control. There were similar rates of bothersome numbness across radiation doses and both treatment targets.Higher radiation dose was associated with superior pain control without increasing bothersome numbness. Independent of dose, the distal target was also associated with improved pain control. Bothersome numbness was not related to dose or target.

Mature thoracic intraspinal teratomas are rare tumors in adults. In this case study, we present a case of intradural, extramedullary teratoma, which was surgically resected. A 50 year old man presented with progressive bilateral leg pain, severe myelopathy and weakness. Magnetic Resonance Imaging (MRI) revealed a cystic mass lesion in the T11-12 region region. Microsurgical resection of the tumor using CO2 laser with neuromonitoring was performed. Postoperatively, the patient had a remarkable clinical improvement. Mature spinal teratomas are rare, slow growing spinal tumors. Surgical resection provides excellent recovery, and recurrence rates are low.

Study Design: A nonrandomized, two-armed prospective study. Objective: Water-tight dural closure is paramount to the prevention of cerebrospinal fluid (CSF) leakage and associated complications. Synthetic polyethylene glycol (PEG) hydrogel has been used as an adjunct to sutured dural repair; however, its expansion postoperatively is a concern for neurological complications. A low-swell formulation of PEG sealant was introduced as DuraSeal Exact Spine Sealant System (DESS). A Post-Approval Study was performed primarily to evaluate the safety and efficacy of DESS for spinal dural repair compared to current alternatives, in a large patient population, reflecting a real-world practice. Methods: A total of 36 sites in the United States enrolled 429 patients treated with DESS as an adjunct to dural repair in the spinal sealant group and 406 patients treated with all other modalities in the control arm, from October 2011 to June 2016. The primary endpoint was the incidence of CSF leak within 90 days of operation. The secondary endpoints evaluated were deep surgical site infection and neurological serious adverse events. Results: The CSF leakage in the DESS group (6.6%) was not significantly different from the control group (6.5%) ( p = .83), and there was no significant difference in the time to first leak. The two groups had no significant differences in deep surgical site infection (1.6% versus control 2.1%, p = .61) or proportion of subjects with neurological serious adverse events (2.9% versus control 1.6%, p = .516). Conclusions: DuraSeal Exact Spinal Sealant is safe when compared to current alternatives for spinal dural repair.

OBJECTIVE:To evaluate whether anterior cervical spine surgery offers sustained (7 years) relief in patients with cervicogenic headaches (CGHs), and evaluate the difference between cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for 1 and 2-level surgeries from a multicenter randomized clinical trial. METHODS:A post hoc analysis was performed of 575 patients who underwent one or 2-level CDA or ACDF for symptomatic cervical spondylosis as part of a prospective randomized clinical trial. Assessment of pain and functional outcome was done with the Neck Disability Index (NDI) in the trial. We used the NDI headache component to assess headache outcome. RESULTS:For both 1- and 2-level CDA and ACDF groups, there was significant headache improvement from preoperative baseline out to 7 years (p < 0.0001). For 1-level surgeries, headache improvement was similar for both groups at the 7-year point. For 2-level treatment, CDA patients had significantly improved headache scores versus ACDF patients at the 7-year point (p = 0.016). CONCLUSION:The headache improvement noted at early follow-up was sustained over the long-term period with ACDF and CDA populations. In the case of 2-level operations, CDA patients demonstrated significantly greater benefit compared to ACDF patients over the long-term. Sinuvertebral nerve irritation at the unco-vasculo-radicular junction and anterior dura may be the cause of CGH. Therefore, it is possible that improved cervical kinematics and preservation of range of motion at adjacent uncovertebral joints in CDA may contribute to the observed difference between the groups.

Stem cells reside in their native microenvironment, which provides dynamic physical and chemical cues essential to their survival, proliferation and function. A typical cell-based therapeutic approach requires the mesenchymal stem cells (MSC) to depart their native microenvironment, transplant to in-vivo environment, differentiate toward multiple lineages and participate in bone formation. The long-term survival, function and fate of MSC are dependent on the microenvironment in which they are transplanted. Transplantation of morselized autologous bone, which contains both stem cells and their native microenvironment, results in a good clinical outcome. However, implantation of bone graft substitutes does not provide the complete and dynamic microenvironment for MSC. Current bone graft therapeutics may need to be improved further to provide an optimal engineered MSC microenvironment.

Background Vertebrobasilar insufficiency resulting from embolism, atherosclerosis, or arterial dissection has long been a challenge for successful management and outcomes. The main treatment options include medical therapy, angioplasty and stenting, and surgical revascularization. Unlike cardiac or peripheral vascular revascularization, large randomized trials with cerebrorevascularization have not revealed favorable outcomes. In patients who have failed maximal medical therapy, and having persistent debilitating symptomology, cerebral revascularization may still be a viable option. Methods We report 3 patients who presented with symptoms of vertebrobasilar ischemia. The diagnosis was verified by computerized tomographic arteriography and digital subtraction angiography. Results These patients subsequently underwent revascularization with a radial artery graft. We also present a comprehensive review of the literature of treatment for vertebrobasilar insufficiency. Conclusions Surgical revascularization should be considered in the posterior circulation in the rare subset of patients with VBI, who remain symptomatic despite having a protracted course of maximal medical therapy with large- and medium-sized vessel occlusions and poor collateral circulation.

Background: The opticocarotid triangle (OCT) and the carotico-oculomotor triangle (COT) are two anatomical triangles used in accessing the interpeduncular region. Our objective is to evaluate if the anterior incisural width (AIW) is an indicator to predict the intraoperative exposure through both triangles. Methods: Twenty sides of 10 cadaveric heads were dissected and analyzed. The heads were divided into the following: Group A – narrow anterior incisura and Group B – wide anterior incisura – using 26.6 mm as a cutoff distance of the AIW. Subsequently, the area of the COT and the OCT in the transsylvian approach was measured, along with the maximum widths through the two trajectories in modified superior transcavernous approach. Results: The COT in the wide group was shown to have a significantly larger area compared with the COT in the narrow group (38.4 ± 12.64 vs. 58.3 ± 15.72 mm, P < 0.01). No difference between the two groups was reported in terms of the area of the OCT (50.9 ± 19.22 mm vs. 63.5 ± 15.53 mm, P = 0.20), the maximum width of the OCT (6.6 ± 1.89 vs. 6.5 ± 1.38 mm, P = 1.00), or the maximum width of the COT (11.7 ± 2.06 vs. 12.2 ± 2.32 mm, P = 0.50). Clinical cases were included. Conclusion: An AIW

Coccidioidomycosis is a fungal infectious disease caused by the Coccidioides species endemic to Southwestern United States. Symptomatic patients typically present as community-acquired pneumonia. Uncommonly, in about 1% of infections, hematogenous extra pulmonary systemic dissemination involving skin, musculoskeletal system, and meninges occur. Disseminated spinal infection is treated with antifungal drugs and/or surgical treatment. A retrospective review of medical records at our institution was done between January 2009 to December 2018 and we present three cases of spinal coccidioidomycosis and review the current literature. Disseminated coccidioidomycosis can lead to spondylitis that can present as discitis or a localized spinal or paraspinal abscess. Spinal coccidioidomycosis is typically managed with antifungal treatments but can include surgical treatment in the setting poor response to medical therapy, intractable pain, presence of neurological deficits due to compression, or structural spinal instability.

Background: Loss of calcium/calmodulin-dependent kinase II (CaMKII) after ischemic stroke exacerbates cell death by sensitizing vulnerable neurons to excitotoxic glutamate signaling and inducing neurotoxicity. Our recent study demonstrated the potential of human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs) treatment in inhibiting apoptosis after ischemic stroke. In this study, we aimed to investigate the effect of focal cerebral ischemia and/or reperfusion on CaMKII expression and the role of HUCB-MSCs treatment on CaMKII regulation. To our knowledge this is the first study that demonstrates the possible involvement of CaMKII in HUCB-MSCs-mediated neuroprotection after ischemic stroke. Methods: Male Sprague-Dawley rats were obtained and randomly assigned to various groups. Rats were subjected to a two-hour middle cerebral artery occlusion (MCAO) procedure followed by seven days reperfusion. HUCB-MSCs (0.25x106cells/animal) were intravenously injected via tail vein 24 hours post-MCAO to designated animals. Rats brain tissues obtained seven days after reperfusion from various groups were subjected to real-time PCR, immunoblot and immunofluorescence analysis. Results: CaMKII protein expression did not change in animals subjected to 1h, 2h, and 4h of ischemia without reperfusion. However, CaMKII expression is significantly reduced when the animals were subjected to ischemia followed by one day reperfusion. The loss of CaMKII was persistent until 14 days after reperfusion. All CaMKII isoforms (CaMKIIα, CaMKIIγ and CaMKIIδ), except CaMKIIβ, were downregulated. CaMKII expression in neurons was also reduced in the ischemic hemisphere. HUCB-MSCs treatment 24h after reperfusion revert CaMKII mRNA and protein expression. Significant co-localization of CaMKII with neurons was also noticed in rats subjected to stem cell treatment. Conclusions: HUCB-MSCs-mediated neuroprotection after ischemic stroke could be mediated by upregulation of neuronal CaMKII expression.

Background Skull base meningiomas represent the paradigm for the evolution of skull base surgery within the past 50 years into a distinct neurosurgical subspecialty. Methods From 2005 to 2011, 117 patients with cranial base meningiomas underwent surgical resection. Extent of resection, histologic grade, complications, functional status, and recurrence-free and overall survival data are presented. Results The summary rate of gross total resection was 53.0%. The surgical complication and mortality rates were 17.9% and 0.9%, respectively. Five-year recurrence-free survival was 88.0% for grade I meningiomas. A total of 90.3% of patients had a Karnofsky performance score ≥80 at last follow-up. Conclusions A large contemporary series of skull base meningiomas is presented. In addition, the evolution of surgical approaches to skull base meningiomas is reviewed, together with the current issues regarding radiation therapy, management of cavernous sinus tumor, oncologic management of atypical and malignant subtypes, molecular genetics, and future therapeutic options.

BACKGROUND Various techniques of cerebral bypasses are used to treat aneurysms and tumors. OBJECTIVE To study long-term clinical and radiological outcome of various bypass types and to analyze techniques used in the management of long-term graft problems. METHODS A consecutive series of patients who underwent revascularization during a 5-year period were analyzed for indications, graft patency, and neurological outcomes. Potential risk factors for bypass problems and the management of bypass stenosis were studied. RESULTS A total of 80 patients (69 with aneurysms and 11 with tumors) underwent 88 bypasses (59 extracranial-to-intracranial [EC-IC] bypasses [10 low flow, 49 high flow], 9 intracranial-to-intracranial [IC-IC] bypasses [3 long, 6 short], and 20 local bypasses), with mean radiological follow-up of 32 months (range, 1-53 months). At late follow-up, 5 of 9 (56%) IC-IC (5 short, 0 long grafts), 8 of 9 (90%) EC-IC low-flow, 44 of 48 (92%) EC-IC high-flow, and all local bypasses were patent. Four patients with EC-IC high-flow bypass occlusions were asymptomatic, but transient ischemic attacks were noted in 3 of 6 patients with graft stenosis. None of the risk factors evaluated were significantly predictive of EC-IC graft occlusions or stenosis. EC-IC HF graft stenoses were permanently corrected by microsurgery (n = 4) or endovascular surgery (n = 1). CONCLUSION The EC-IC and local bypasses have higher long-term patency rates (91% and 100%) compared with IC-IC bypasses (66%, 0% long graft). Some EC-IC bypasses may occlude asymptomatically (9%) or develop graft stenosis (13%) over the long term. Microsurgical and endovascular surgical techniques have been developed to treat graft stenosis.

Epidermoid cysts are histologically benign, slow-growing congenital neoplasms of the central nervous system that may arise from retained ectodermal implants. The epidermoid lesions are generally caused during the 3 rd to 5 th week of gestation by an incomplete cleavage of the neural tissue from the cutaneous ectoderm, though it can also happen later in life due to introduction of skin elements by skin puncture, trauma or surgery. We present this unique case of a petromastoid epidermoid cyst associated with ipsilateral cerebellar abscesses, presenting 20 years after a penetrating trauma to the external auditory canal. Radical excision of both lesions and revision of the previous fistulous tract was performed. We present the diagnostic challenge and the operative treatment of this unique case, which to our knowledge is the first where an epidermoid cyst and an adjacent brain abscess occurred as a result of a single traumatic event.

Objective. Trigeminal neuralgia is rarely caused by arteriovenous malformations of the posterior fossa. Embolization of aberrant vessels can provide symptomatic relief; however, embolization is not always technically possible, and its effects can be temporary. Embolization of the nerve's blood supply could reduce its excitability and provide pain relief. Setting. The study was set in an academic tertiary care center. Study Design. The study was designed as a report of a clinical case. Summary. The authors report the case of a 13-year-old girl with a large, unruptured posterior fossa arteriovenous malformation (AVM) presented with left-sided V2-division trigeminal neuralgia. She had undergone multiple previous embolizations of feeding vessels from the anterior inferior cerebellar artery with temporary relief of her symptoms. Embolization of the middle meningeal artery was attempted, but the vessel's tortuosity precluded safe catheterization. Instead, the artery of the foramen rotundum, which had minimal contribution to the AVM nidus, was embolized with Onyx copolymer. The patient had immediate cessation of her neuralgia, with a small area of hypesthesia above her left cheek. Complete pain relief lasted for 8 months, followed by a return of mild dysesthesia episodes not requiring intervention. Conclusion. This case may represent a new method of palliative treatment for AVM-associated trigeminal neuralgia, or potentially trigeminal neuralgia of other etiologies. Based on this case's success, a prospective study using additional provocative testing with intraarterial lidocaine is proposed.

Object The role of surgery and adjuvant radiation therapy for cranial base chordomas is not well established. This meta-analysis measures the relationship of complete resection and type of adjuvant radiation therapy to 5-year progression-free survival (PFS) and overall survival (OS) of cranial base chordomas. Methods A systematic MEDLINE search (1999–present) yielded 23 observational studies and 807 patients who fit inclusion criteria. The following analyses were performed: 1) Kaplan-Meier 5-year PFS and OS compared based on the extent of resection and type of adjuvant radiation therapy using the log-rank method; 2) a random-effects model comparing 5-year PFS with complete or incomplete resection; and 3) paired z-test comparisons of weighted average 5-year OS and PFS grouped by type of adjuvant radiation therapy. Results The weighted average follow-up was 53.6 months. The weighted average 5-year PFS and OS were 50.8% and 78.4%, respectively. Complete resection conferred a higher 5-year PFS than incomplete resection from the random effects model (mean difference in PFS 20.7%; 95% CI 6.57%–34.91%). Patients with incomplete resection were 3.83 times more likely to experience a recurrence (95% CI 1.63–9.00) and 5.85 times more likely to die (95% CI 1.40–24.5) at 5 years versus patients with complete resection. There was no difference in 5-year OS by type of adjuvant radiation, although 5-year PFS was lower in patients receiving Gamma Knife surgery relative to carbon ion radiotherapy (p = 0.042) on paired z-test. No survival difference occurred between radiation therapy techniques on Kaplan-Meier analysis of compiled patient data. Conclusions Patients with complete resection of cranial base chordomas have a prolonged 5-year PFS and OS. Adjuvant proton-beam, carbon ion, and modern fractionated photon radiation therapy techniques offered a similar rate of PFS and OS at 5 years.

BACKGROUND: The sequelae of aneurysmal subarachnoid hemorrhage (SAH) include vasospasm and hydrocephalus. OBJECTIVE: To assess whether intraventricular tissue plasminogen activator (tPA) results in less vasospasm, fewer angioplasties, or fewer cerebrospinal fluid shunting procedures. METHODS: 41 patients (tPA group, Hunt and Hess 3, 4, 5) from 2007 to 2008 received intraventricular tPA and lumbar drainage for a minimum of 5 days (range 5-7 days) and were compared to a matched group of 35 patients from 2006 to 2007 (Control, HH 3,4,5). Statistical comparison was done by t test analysis or Fisher exact tests and data are expressed as average ± standard error of the mean. RESULTS: There were no significant differences in demographic data, although the tPA group had a trend toward more surgical patients. The tPA group of patients had a significantly higher modified Fisher grade than controls (P < .001) and had a significantly better Hunt and Hess grade than controls (P < .03). The angioplasty rate was significantly lower among the tPA patients (15.0% ± 5.6) than controls (40.0% ± 8.5, P= .0 1 9). The number of days spent in severe vasospasm normalized over the 14-day monitoring period by transcranial Doppler was significantly lower in the tPA group (0.09 ± 0.02) than controls (0.17 ± 0.03). The shunt rate was significantly lower among tPA patients (17.5% ± 6.0) than controls (42.8% ± 8.6).There were 2 clinically silent tract hemorrhages in the tPA group (4.8%). CONCLUSION: Intraventricular tPA is a safe and effective treatment for reducing both angioplasty and shunting rates in patients with SAH H&H Grades 3 to 5. A randomized trial is indicated.

The problem of power management for an embedded system is to reduce system level power dissipation by shutting off parts of the system when they are not being used and turning them back on when requests have to be serviced. Algorithms for this problem are online in nature; the algorithm must operate only with access to data that it has seen so far and without access to the complete data set or its characteristics. We present online algorithms to manage power for embedded systems and discuss their effects on system latency. We introduce competitive analysis as a formal framework for the evaluation of various power management algorithms. Competitive analysis does not depend on the distribution of interarrival times of requests. We present a nonadaptive online algorithm, analyze its behavior, and show that it is optimal. We also present a lower bound on the competitiveness of any adaptive algorithm. We show that no adaptive online algorithm can dissipate less than about 1.6 times the power dissipated by the optimal offline algorithm in the worst case. We also show that in order for any online algorithm to achieve this lower bound, it may have to maintain a complete history of the interarrival. times of the requests in the input sequence. Since this is not practical, we present a simple algorithm that uses only the last interarrival time to predict the arrival of the next request.

We address the problem of timing constraint derivation and validation for reactive and real-time embedded systems. We assume that such a system is structured into its tasks, and the structure is modeled using a task graph. Our solution uses the timing behavior committed by the environment to the system first to derive the timing constraints on the system's internal behavior and then use them to derive and validate the timing constraints on the system's external behavior. Our solution consists of the following contributions: a generalized task graph model, a comprehensive classification of timing constraints, algorithms for derivation and validation of timing constraints of the system modeled in the generalized task graph model, a codesign methodology that combines the model and the algorithms, and the implementation of this methodology in a tool called RADHA-RATAN. The main advantages of our solution are that it simplifies the problem of ensuring timing correctness of the system by reducing the complexity of the problem from system level to task level, and that it makes the codesign methodology timing-driven in that our solution makes it possible to maintain a handle on the system's timing correctness from very early stages in the system's design flow.

Background Spinal epidural arteriovenous fistulas (SEDAVF) are rare and poorly understood clinical entities. Materials and methods We report a series of five (three men, two women) consecutive cases treated at our center to analyze their characteristic and treatment strategies in their management. We report a successful technique of percutaneous embolization of fistulas in a patient with failed previous attempts. Results All five patients were symptomatic; three patients presented with a history of back pain, which progressed to myelopathic symptoms, one patient had symptoms of persistent back pain, and one patient had intermittent numbness of the left arm and thigh. Of the three patients who had myelopathic symptoms, two were successfully treated with transarterial embolizations with Onyx copolymer. The third patient who had a prominent epidural venous pouch with numerous arterial feeders was embolized percutaneously with a flat detector CT guided navigation (XperCT) and real time fluoroscopic monitoring of the injected n-butyl cyanoacrylate glue, after previous unsuccessful attempts with surgery and arterial embolizations. All three myelopathic treated patients had complete angiographic remission of the fistulas and symptoms on follow-up (mean 7.2 months). Conclusions The diagnosis and treatment of SEDAVF can be challenging due to their rarity and intricate pathomechanics. Patients with severe pain or progression of symptoms or myelopathic symptoms need to be treated at the earliest opportunity, while asymptomatic patients can be closely monitored. Percutaneous embolization is an effective strategy to embolize SEDAVF associated venous pouch.

Giant basilar tip aneurysms are a challenge to treat because of the complex anatomy and critical vessels that arise in this region. For large aneurysms, with multiple recurrences after coiling, when microsurgical clipping is not possible, a bypass to the posterior cerebral artery (PCA) can be helpful in providing definitive treatment. Two patients with giant basilar tip aneurysms were treated with bypass to the PCA. One patient had a microsurgical clipping and the other had a proximal occlusion of the basilar artery along with the bypass. Long-term angiographic and clinical follow-up was obtained. One patient had marked improvement in symptoms and a stable aneurysm remnant and the other patient had complete occlusion. Surgical treatment with a bypass to the PCA, with clipping of the aneurysm or proximal ligation of the basilar artery can be an effective treatment option for giant basilar tip aneurysms.

Objective The purpose of this study is to provide an institutional retrospective review of surgically treated brainstem cavernous malformations. Methods Between 2005 and 2010, 22 consecutive patients with brainstem cavernous malformations (15 female and 7 male) with a mean age of 43 years underwent surgical treatment. Mean volume of the resected cavernous malformations was 0.65 cm 3 . A minimally invasive resection technique was used for these cases, in conjunction with skull base approaches. Results The mean follow-up period was 26.6 months (range, 4-68 months). Of the 22 patients, 9% did not have clear evidence of hemorrhage at the time of presentation. Of the remainder, 22% had two or more instances of hemorrhage documented by magnetic resonance imaging. After resection and during follow-up, 54% of patients had an improvement in their modified Rankin scale, whereas 14% were worse compared with their preoperative presentation; 32% were unchanged and 9% of patients were found to have residual cavernoma post-surgery. Conclusion Our longitudinal experience has guided us to emphasize minimally invasive approaches during resection of the brainstem cavernous malformations, occasionally at the expense of achieving a complete resection, to improve patient outcomes.

BACKGROUND AND PURPOSE: Cerebral bypass grafts may develop generalized graft narrowing or focal stenosis during the perioperative period or later. Endovascular techniques such as PTA and stent placement of graft vessels are potential treatment options. Our objective was to review the safety, indications, technique, and results of endovascular management of graft problems. MATERIALS AND METHODS: All patients with cerebral bypass procedures by using graft vessels from 2005 to 2009 were identified from a prospective registry and were studied retrospectively. Patient characteristics, bypass procedures, indications for endovascular interventions, graft patency, and clinical outcomes were reviewed from medical charts and imaging records. RESULTS: A total of 79 patients underwent bypass procedures by using graft vessels. Seven patients of this group underwent endovascular interventions for the treatment of graft narrowing. Four of the 7 patients were treated for graft narrowing in the perioperative period (

The role of surgery and adjuvant radiation therapy for cranial base chordomas is not well established. This meta-analysis measures the relationship of complete resection and type of adjuvant radiation therapy to 5-year progression-free survival (PFS) and overall survival (OS) of cranial base chordomas.A systematic MEDLINE search (1999-present) yielded 23 observational studies and 807 patients who fit inclusion criteria. The following analyses were performed: 1) Kaplan-Meier 5-year PFS and OS compared based on the extent of resection and type of adjuvant radiation therapy using the log-rank method; 2) a random-effects model comparing 5-year PFS with complete or incomplete resection; and 3) paired z-test comparisons of weighted average 5-year OS and PFS grouped by type of adjuvant radiation therapy.The weighted average follow-up was 53.6 months. The weighted average 5-year PFS and OS were 50.8% and 78.4%, respectively. Complete resection conferred a higher 5-year PFS than incomplete resection from the random effects model (mean difference in PFS 20.7%; 95% CI 6.57%-34.91%). Patients with incomplete resection were 3.83 times more likely to experience a recurrence (95% CI 1.63-9.00) and 5.85 times more likely to die (95% CI 1.40-24.5) at 5 years versus patients with complete resection. There was no difference in 5-year OS by type of adjuvant radiation, although 5-year PFS was lower in patients receiving Gamma Knife surgery relative to carbon ion radiotherapy (p = 0.042) on paired z-test. No survival difference occurred between radiation therapy techniques on Kaplan-Meier analysis of compiled patient data.Patients with complete resection of cranial base chordomas have a prolonged 5-year PFS and OS. Adjuvant proton-beam, carbon ion, and modern fractionated photon radiation therapy techniques offered a similar rate of PFS and OS at 5 years.

Background Extracranial-to-intracranial (EC-IC) bypass is a valuable tool in treating intracranial diseases requiring flow replacement or parent vessel sacrifice. Radial artery grafts (RAGs) and saphenous vein grafts (SVGs) have been used as conduits to provide adequate high flow revascularizations. It is a therapeutic challenge when these grafts are unavailable. Methods All EC-IC high flow cerebral revascularizations performed using conduits other than RAGs or SVGs were identified from a prospective cerebrovascular registry. These patients were retrospectively reviewed for surgical technique, graft patency, graft flow, and clinical outcomes. Results Three patients (all women) underwent EC-IC bypass surgery using tibial artery grafts (two anterior tibial artery and one posterior tibial artery) because of the nonavailability of RAG or SVG. The two anterior tibial artery graft bypasses were patent with good flow at 8 and 3 months. The posterior tibial artery graft occluded intraoperatively. None of the patients developed vascular complications in the lower extremity due to tibial artery harvest. Conclusions Tibial arteries are safe, contingent alternatives to conventional conduits for performing high flow cerebral revascularizations and conduit reconstructions.