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Bilaterally fixed and dilated pupils in the setting of transtentorial herniation have traditionally been considered a sign of futility. Such patients are often denied life-saving surgery based on the premise that meaningful functional recovery would be extremely unlikely. We sought to determine the survival and functional outcome in a cohort of patients who underwent aggressive medical and surgical management.Charts of all patients managed by a single surgeon over a 42-month period were retrospectively reviewed. Functional outcome was determined using modified Rankin Scale (mRS). Outcome was classified as good (mRS score 0-3), acceptable (mRS score 4), or poor (mRS score 5-6).Patients were 7 men and 2 women with a mean age of 36 years (range, 16-66 years). Etiologies included stroke (4 patients), traumatic brain injury (4 patients), and malignant cerebral edema (1 patient). Preoperative Glasgow Coma Scale scores ranged from 3 to 7, and midline shift was 7-16 mm. All patients received emergency osmotic therapy before decompressive surgery. Time to surgery (from pupillary changes) was150 minutes for all patients (median 94 minutes; range, 50-148 minutes). At 3 months, 5 patients (55.6%) had recovered, achieving a good (n = 3) or acceptable (n = 2) outcome. The other 4 patients failed to recover and ultimately died of their injury.In well-selected patients with transtentorial herniation and bilaterally fixed and dilated pupils, aggressive and timely medical and surgical management may lead to substantial rates of survival and favorable functional outcome. Preconceived notions of a universally grim prognosis in such patients can lead to self-fulfilling prophecies.

Although several material options, both natural and synthetic, are available for cranioplasty, the rate of implant-related complications has remained high. A relatively novel, synthetic hydroxyapatite-titanium implant, which combines biocompatibility with biomechanical resilience, has been reported to reduce tissue inflammation, infection, and explantation rates, while delivering superior cosmetic results. However, despite such promising preliminary reports, clinical data supporting its use have remained scarce.All the patients who had undergone cranioplasty between 2019 and 2022 using this implant were identified from a prospectively maintained database. Medical records were retrospectively reviewed and the following variables recorded: demographic data, clinical data, radiologic findings, operative details, complications (implant-related and unrelated), and outcomes.A total of 18 patients (12 men and 6 women), with a mean age of 39 years (range, 20-70 years), were identified. The indications for craniectomy were traumatic brain injury (n = 13; 72.2%), hemorrhagic stroke (n = 3; 16.7%), and ischemic stroke (n = 2; 11.1%). The median time to cranioplasty was 140 days (range, 51-1717 days). The median modified Rankin scale score before cranioplasty was 4 (range, 0-5). Cranioplasty was technically successful in all 18 patients. Minor postoperative complications, none related to the implant, were managed conservatively in 3 patients (16.6%), including a small intraparenchymal hematoma in 1, an extra-axial hematoma in 1, and a seizure in 1. Of these 3 patients, 1 (5.6%) died 1 week later of a suspected pulmonary embolism. No implant-related complications occurred after a median follow-up of 6 months (range, 1-38 months). All 17 survivors exhibited some degree of neurologic improvement. The cosmetic result was good or excellent for all patients.Our experience, the largest in the United States, confirms the previously reported benefits associated with the use of 3-dimensional-printed hydroxyapatite-titanium cranioplasty implants.

Bilaterally fixed and dilated pupils (BFDP) in the setting of transtentorial herniation due to a space-occupying lesion have traditionally been considered a sign of futility. As a result, such patients may be denied life-saving decompressive surgery, resulting in very high mortality rates. We sought to determine the survival rate and functional outcomes in patients with transtentorial herniation and BFDP following emergency decompressive surgery.This was a systematic review of MEDLINE, Embase, Cochrane, and Google Scholar databases, using a combination of 15 prespecified keywords, according to Preferred Reporting Items for Systematic reviews and Meta-Analyses methodology. Individual patient data were extracted, pooled, and analyzed.Twenty-two studies totaling 503 patients were included. Study designs were as follows: prospective cohort (n = 1), retrospective cohort (n = 15), and case report (n = 6). Nearly two thirds of patients (67.7%) were male. The mean age was 41 years (range = 3-82). The median preoperative Glasgow coma scale was 3 (range = 3-6). Nearly two thirds (66.9%) underwent surgical decompression within 2 hours of pupillary changes. The mean follow-up was 7 months (range = 1-40). Two thirds (67%) died. Among survivors, 50.5% had severe disability (Glasgow outcome scale = 2-3), while 49.5% had a good outcome (Glasgow outcome scale 4-5), representing 17% of the whole population. Given the methodological limitations, the prognostic value of age, Glasgow coma scale, and time to surgery could not be determined.The literature suggests a rate of favorable recovery approaching 17% following decompressive surgery in patients with transtentorial herniation and BFDP, secondary to space-occupying lesions. In the setting of stroke or trauma, the clinical finding of BFDP should not be solely relied on as an indicator of futility. Prospective studies are warranted.

Dialysis disequilibrium syndrome (DDS) is a rare, well-known, potentially life-threatening complication of renal replacement therapy (RRT), often involving cerebral edema and increased intracranial pressure (ICP). However, the impact of RRT on ICP and rate of DDS in neurosurgical patients have not been systematically assessed.In February 2022, a systematic review following PRISMA guidelines was conducted using various combinations of 9 keywords in MEDLINE. Eleven papers were selected. Individual patient data were extracted, pooled, and analyzed.Fifty-eight patients, 44 men and 14 women with mean age 48 years (6-78), were analyzed. Neurosurgical conditions included: spontaneous intracranial hemorrhage (n=27), traumatic brain injury (n=16), ischemic stroke/anoxic brain injury (n=6), intracranial tumor (n=6), other (n=3). Neurosurgical interventions included: craniotomy/craniectomy (n=23), external ventricular drain or ICP monitor placement (n=16), burr hole or twist drill craniostomy (n=4). Intermittent dialysis was used in 33 patients, continuous RRT in 20, and a combination thereof in 4. During RRT, ICP increased in 35 patients (60.3%), remained unchanged in 20, decreased in 3. Thirty-four patients died. Intermittent dialysis was associated with increased ICP (73% vs. 37.5%, p=0.01) and mortality (75% vs. 39.1%, p=0.01).In neurosurgical patients, ICP increases during RRT are common, affecting up to 60%, and potentially life-threatening, with mortality rates as high as 65%. The use of a continuous rather than intermittent RRT technique may reduce the risk of this complication. Prospective studies are warranted.

Background Quantitative magnetic resonance angiography (qMRA) using noninvasive optimal vessel analysis (NOVA) is a novel noninvasive imaging technique that is being increasingly used to measure blood flow in extracranial and intracranial arteries. By providing important quantitative flow data, NOVA qMRA can facilitate the management of cerebrovascular disease. While the same technology can also be applied to measure flow in intracranial and extracranial veins, NOVA quantitative MRV (qMRV) is only rarely used in neurovascular practice. Case Description We report interesting qMRV data in 2 patients with symptomatic intracranial arteriovenous shunts: a 61-year-old man with a left transverse-sigmoid dural arteriovenous fistula and a 40-year-old woman with a left parietal arteriovenous malformation. In each patient, NOVA qMRV demonstrated significant reduction of intracranial venous outflow after therapeutic obliteration of the shunt lesion, heralding marked clinical improvement. Conclusions To the best of our knowledge, this is the first report of successful clinical application of NOVA qMRV in adult patients with intracranial arteriovenous malformations or dural arteriovenous fistulas. We propose that NOVA qMRV is a promising technique for noninvasive measurement of intracranial and extracranial venous blood flow and for monitoring treatment effectiveness in patients with intracranial arteriovenous shunt lesions.

BACKGROUND Nonmissile penetrating spinal injuries are rare and potentially debilitating. Such injuries can sometimes be complicated by the retention of a foreign body, which is usually part of the assailant’s weapon, making their management even more problematic. OBSERVATIONS We present a unique case of stab wound to the neck with a retained ice pick, traversing the spinal canal from one intervertebral foramen to the other, yet with no ensuing neurological damage to the patient. After carefully analyzing the weapon’s trajectory on computed tomography and ruling out vertebral artery injury via catheter angiography, the ice pick was successfully withdrawn under general anesthesia and intraoperative neurophysiological monitoring, averting the need for a more invasive surgical procedure. LESSONS Stab wounds of the spinal canal with a retained foreign body can occasionally be managed by direct withdrawal. Whether this simple technique is a safe alternative to open surgical exploration should be determined on a case-by-case basis after careful review of spinal and vascular imaging. The absence of significant neurological or vascular injury is an absolute prerequisite for attempting direct withdrawal. Moreover, preparations should be made for possible conversion to open surgical exploration in the rare event of active hemorrhage, expanding hematoma, or acute neurological deterioration.

IntroductionRecently, there has been a paradigm shift in the management of hypothalamic hamartoma (HH) from traditional microsurgical techniques to less invasive alternatives such as stereotactic radiosurgery and laser interstitial thermal therapy. However, large and extensive HH may fail to respond to minimally invasive therapies, ultimately necessitating microsurgery.MethodsAll patients who underwent microsurgical resection of a complex HH by the 2 senior authors (D.J.L., H.L.R.) in 2011-2017 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, and outcome data were recorded.Results8 patients, 7 children and 1 adult, with a mean age of 7 years (10 months-27 years), were included. Of those, 2 had failed previous treatments. All 7 children presented with pharmacoresistant gelastic seizures and cognitive dysfunction, 6 exhibited central precocious puberty, and 3 had behavioral problems. Other seizure types affected 6/8 patients. Mean lesion size was 21.6 mm (14-31), all with interpeduncular extension and 5 with intraventricular extension (Delalande type I: 3, type III: 4, type IV: 1). A frontotemporal orbitozygomatic (FTOZ) approach with optic nerve decompression was used in all patients, supplemented by another approach in 3 (endoscopic transventricular: 3, transcallosal: 1). Gross total resection was achieved in 6 patients and subtotal resection in 2. Transient complications occurred in 3 patients (37.5%): self-limited sodium imbalance (n=3), subdural hygroma (n=2). Permanent complications occurred in 2 patients (25%): perforator infarct (n=1), short-term memory loss (n=1). All patients experienced seizure resolution postoperatively with preserved hypothalamic-pituitary axis function. After a mean follow-up of 41 months (2-66), 7 patients remain seizure-free, while 1 has rare recurrent seizures. Cognitive and behavioral symptoms improved significantly in all patients.Conclusion For large HH with interpeduncular extension, microsurgery via the FTOZ approach is a safe and highly effective treatment modality.

BACKGROUNDWe present a systematic review and pooled analysis of clinical studies to date, that (1) specifically compare the protection of natural immunity in the COVID-recovered versus the efficacy of full vaccination in the COVID-naive, and (2) the added benefit of vaccination in the COVID-recovered, for prevention of subsequent SARS-CoV-2 infection.METHODSUsing the PRISMA 2020 guidance, we first conducted a systematic review of available literature on PubMed, MedRxIV and FDA briefings to identify clinical studies either comparing COVID vaccination to natural immunity or delineating the benefit of vaccination in recovered individuals. After assessing for eligibility, studies were qualitatively appraised and formally graded using the NOS system for observational, case-control and RCTs. Incidence rates were tabulated for the following groups: never infected (NI) and unvaccinated (UV), NI and vaccinated (V), previously infected (PI) and UV, PI and UV. Pooling was performed by grouping the RCTs and observational studies separately, and then all studies in total. Risk ratios and risk differences are reported for individual studies and pooled groups, in 1) NPI/V vs. PI/UV and 2) PI/UV vs. PI/V analysis. In addition, number needed to treat (NNT) analysis was performed for vaccination in naïve and previously infected cohorts.RESULTSNine clinical studies were identified including three randomized controlled studies, four retrospective observational cohorts, one prospective observational cohort, and a case-control study. The NOS quality appraisals of these articles ranged from four to nine (out of nine stars). All of the included studies found at least statistical equivalence between the protection of full vaccination and natural immunity; and, three studies found superiority of natural immunity. Four observational studies found a statistically significant incremental benefit to vaccination in the COVID-recovered individuals. In total pooled analysis, incidence in NPI/V trended higher than PI/UV groups (RR=1.86 [95%CI 0.77-4.51], P=0.17). Vaccination in COVID-recovered individuals provided modest protection from reinfection (RR=1.82 [95%CI 1.21-2.73], P=0.004), but the absolute risk difference was extremely small (AR= 0.004 person-years [95% CI 0.001-0.007], P=0.02). The NNT to prevent one annual case of infection in COVID-recovered patients was 218, compared to 6.5 in COVID-naïve patients, representing a 33.5-fold difference in benefit between the two populations.CONCLUSIONSWhile vaccinations are highly effective at protecting against infection and severe COVID-19 disease, our review demonstrates that natural immunity in COVID-recovered individuals is, at least, equivalent to the protection afforded by full vaccination of COVID-naïve populations. There is a modest and incremental relative benefit to vaccination in COVID-recovered individuals; however, the net benefit is marginal on an absolute basis. COVID-recovered individuals represent a distinctly different benefit-risk calculus. Therefore, vaccination of COVID-recovered individuals should be subject to clinical equipoise and individual preference.

Background Spontaneous migration of retained intracranial bullet fragments is an increasingly recognized phenomenon. However, such migration is usually limited in extent, since it occurs along the bullet tract or cerebrospinal fluid (CSF) spaces. Transhemispheric migration through an intact cerebral hemisphere has not been previously reported. Observations A 20-year old man sustained a gunshot wound (GSW) to the head with a left parieto-occipital entry point, resulting in retained bullet fragments within the anterior right frontal lobe. The patient developed medically refractory intracranial hypertension, necessitating a left decompressive hemicraniectomy. He exhibited a favorable postoperative course, with gradual neurologic recovery, and was ultimately discharged to a rehabilitation facility. Notwithstanding, serial head CT scans during the first 2 weeks revealed gradual transhemispheric migration of bullet fragments from the right frontal pole to the right occipital pole, traveling through largely intact, uninjured brain tissue. Lessons Transhemispheric migration of bullet fragments via intact brain tissue may rarely occur. While the exact mechanisms underlying this phenomenon remain unclear, potential factors may include: bullet weight, CSF pulsations, dissection through white matter tracts, and biomechanical effects of large skull defects. Bullet migration does not necessarily delay or prevent neurologic recovery.

Introduction Gunshot wounds (GSW) to the cervical spine remain uncommon. Surgery often does not yield significant neurological improvement and the decision to utilize surgery depends on a number of factors. We describe the case of a 28 year-old male suffering a complete spinal cord injury (SCI) secondary to a bullet lodged in the cervical spinal canal. We present the unique radiological findings and review the indications for and utility of spine surgery for cervical GSW. Case presentation The patient was a 28 year-old male involved in a motor vehicle accident immediately after sustaining a gunshot wound to the cervical spine. Neurologic exam revealed a complete SCI at the C4 level. CT scan revealed a retained bullet in the spinal canal at the C4/5 level without vascular injury or unstable vertebral fracture. He was managed nonoperatively, however, he remained ventilator dependent and ultimately expired secondary to cardiac arrest from a suspected pulmonary embolism. Discussion We present a case of complete SCI secondary to a retained bullet in the cervical spine. These cases can be managed both operatively and nonoperatively. Given the high risk of morbidity and overall poor neurological recovery after surgical intervention for SCI secondary to GSW, physicians must understand the appropriate indications for surgical intervention. These indications include, but are not limited to, progressive neurological deficit, cerebrospinal fluid leak, spinal instability, and acute lead toxicity.

Background and importance Cerebral hyperperfusion syndrome (CHS) is a well-known complication of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass for ischemic cerebrovascular disease. While this argues against "low flow" in the bypass construct, flow rates in the graft have not been previously quantified in the setting of CHS. Clinical presentation A 58-yr-old man presented with recurrent left hemispheric ischemic strokes and fluctuating right hemiparesis and aphasia. Vascular imaging revealed left cervical internal carotid artery occlusion and perfusion imaging confirmed left hemispheric hypoperfusion. After failing to respond to maximal medical therapy, the patient underwent single-barrel STA-MCA bypass. Postoperatively, his symptoms resolved and blood pressure (BP) was strictly controlled within normal range. However, 2 d later, he developed severe expressive aphasia. CTA demonstrated a patent bypass graft and SPECT showed focal hyperperfusion in Broca's speech area. Seizure activity was ruled out. A high graft flow rate of 52 mL/min was documented by quantitative magnetic resonance angiography (MRA). Thus, the diagnosis of CHS was made and managed with strict BP control. The patient exhibited complete recovery of speech over a period of days and was discharged home. Repeat SPECT at 4 mo showed resolution of hyperperfusion and quantitative MRA demonstrated reduction of graft flow rate to 34 mL/min. Conclusion This is the first case of perfusion imaging-proven CHS after STA-MCA bypass, where high graft flow rates are objectively documented. Our observations constitute irrefutable evidence challenging the classic belief that the STA-MCA bypass is a low-flow construct.

A 27-year-old man developed sudden neck pain, severe quadriparesis, and right shoulder allodynia during an outpatient cervical medial branch block procedure. Cervical spine imaging revealed evidence of an interlaminar needle trajectory with abnormal signal in the right hemicord at the level of C4, consistent with intramedullary injection and contusion. Following a 48-hour stay in the intensive care unit, during which hemodynamic vasopressor support was administered to optimize spinal cord perfusion, the patient exhibited almost complete neurologic recovery with resolution of the neuropathic pain. He was eventually discharged home and underwent outpatient physical therapy for a mild residual right hemiparesis.

Background Most high-riding distal basilar trunk aneurysms can be surgically approached via the transsylvian route and its orbitozygomatic variant. However, on rare occasions, the basilar bifurcation may be unusually high and an approach above the carotid terminus may be required. Objective In this cadaveric study, we sought to determine the feasibility and exposure limits of the interlenticulostriate approach (ILSA). Methods A standard transsylvian approach was performed in 10 cerebral hemispheres of 5 formalin-fixed, silicone-injected cadaver heads. The interpeduncular cistern was exposed via the opticocarotid window, carotid-oculomotor window, and supracarotid ILSA window. The latter was measured and an aneurysm clip or ventriculostomy stylet was placed as high as possible through each corridor. Using noncontrast 3-D rotational angiography, clip/stylet positions were measured relative to the dorsum sellae. Results ILSA provided a 9.4 × 4.6 mm mean surgical corridor, just enough room for a standard clip applier. This space was limited by the carotid bifurcation inferiorly, the lenticulostriate arteries medially and laterally, and the optic tract superiorly. There was no difference between opticocarotid and carotid-oculomotor windows, in terms of clip position (+8.9 vs +8.6 mm, respectively; P = .78). In contrast, ILSA provided significantly improved superior exposure, compared with either approaches (mean stylet position: +14.3 mm; P = .005). The exposure benefit afforded by ILSA was consistent across all 10 hemispheres, ranging from +2.5 to +8 mm. Conclusion For high-riding distal basilar trunk aneurysms that cannot be reached via the frontotemporal orbitozygomatic approach, ILSA can provide a viable route of access. Vascular neurosurgeons should be familiarized with this approach.

Objectives CT angiography (CTA) is gradually replacing digital subtraction angiography (DSA) in the etiologic workup of intracranial hemorrhage, though debate persists regarding its diagnostic accuracy. To better define the role of CTA in a pragmatic, real-world setting, we reviewed the experience of a single dual vascular-endovascular neurosurgeon. Patients and methods Nontraumatic intracranial hemorrhage cases managed by the senior author over a 15-month period were retrieved from a prospectively maintained database. Cases where a hypertensive etiology was presumed were excluded. Demographics, intracranial hemorrhage pattern, CTA and DSA findings were recorded. Results The study cohort consists of 59 cases where both CTA and DSA were obtained, including 32 women and 27 men with mean age 50 years (18–83). Intracranial hemorrhage pattern was: aneurysmal subarachnoid hemorrhage (SAH) in 37, perimesencephalic SAH (PMSAH) in 8, intraparenchymal in 11, intraventricular in 2, subdural in 1. The overall yield of vascular imaging was 62.7 % (37/59): 29 saccular aneurysms, 4 dissecting aneurysms, 4 microarteriovenous malformations (microAVMs). The specificity and positive predictive value of CTA were 100 %. Its sensitivity and negative predictive value were only 89.2 % and 84.6 %, respectively. CTA missed 4 lesions: 2 dissecting aneurysms, 1 microAVM, 1 small saccular aneurysm. Of 8 patients with PMSAH, 3 (37.5 %) had a vascular lesion: 1 vertebrobasilar dissection, 1 cerebellar microAVM, 1 basilar tip aneurysm. Of those, 2 were missed by CTA. Conclusions DSA may identify a lesion in up to 15 % of intracranial hemorrhage cases with negative CTA. Excessive reliance on CTA can be potentially hazardous, especially in the setting of PMSAH.

Background Moyamoya is a rare, yet classic etiology of stroke in young adults, affecting predominately women of childbearing age. The impact of pregnancy on the natural history of symptomatic moyamoya remains a matter of extensive debate, however. Methods In October 2017, a MEDLINE search was performed using 14 keywords. A total of 12 original articles reporting on cohorts of at least 5 patients were retrieved and reviewed. Individual study data were extracted, pooled, and analyzed. Results A total of 736 pregnancies in 483 patients were included in our analysis. The mean age at delivery was 31 years, and the mean age at diagnosis (before pregnancy) was 22.6 years. Clinical presentation was ischemic stroke in 50.8%, hemorrhagic stroke in 45.9%, headaches in 2.1%, and ischemic-hemorrhagic stroke in 1.2%. After excluding patients first diagnosed during or after pregnancy (n = 283) and those who had been revascularized before pregnancy (n = 183), a total of 270 pregnancies in 188 patients were analyzed. During 224.6 patient-years of follow-up, 22 moyamoya-related neurologic events occurred (annual event rate 9.8%), more than two-thirds of which were transient (12 transient ischemic attacks and 3 seizures). Seven strokes occurred (6 hemorrhagic and 1 ischemic), yielding an annual stroke risk of 3.1%. As a result, 1 patient died and 2 were permanently disabled (annual death/disability rate 1.3%). All remaining patients experienced favorable functional outcomes. Conclusions The risk of moyamoya-related stroke during pregnancy, delivery, and the postpartum period appears to be similar to or lower than that suggested by published natural history studies in symptomatic patients. A neuroprotective effect of pregnancy in moyamoya patients cannot be excluded.

Intracranial aneurysms that are neither clippable nor coilable often require a deconstructive procedure to eliminate the risk of hemorrhage. In that setting, cerebral revascularization may become necessary to replace blood flow after parent artery sacrifice and, in the case of ruptured aneurysms, to prevent delayed cerebral ischemia. In this chapter, we guide the reader through the process of surgical decision-making in these challenging cases, as we elaborate on the management strategies and some of the technical nuances of microsurgical trapping and bypass.

Despite the lack of conclusive outcome data, surgical evacuation of large, symptomatic intracerebral hematomas (ICH) may be offered to patients on a case-by-case basis, aiming to prevent brain herniation, control intracranial pressure, relieve symptoms, and possibly facilitate or accelerate recovery. 1 , 2 , 3 For deep ICH, minimally invasive techniques, which limit operative damage to healthy brain tissue, are generally preferred. Although new tube and endoscope-based techniques are currently being studied, 4 , 5 , 6 , 7 those elaborate techniques are not widely available and often require special equipment and/or expensive disposable material. In this operative video ( Video 1 ), we demonstrate a minimally invasive microsurgical approach for the evacuation of deep ICH, which relies on the use of careful preoperative planning, frameless stereotactic neuronavigation, and meticulous microsurgical technique. This technique involves small craniotomies, infracentimetric corticotomies, and physiologic subcortical white matter dissection, leading to very limited disruption of healthy brain tissue, akin to tube and endoscope-based procedures. We acknowledge that this technique or a modification thereof may currently be in use by other neurosurgeons in their practice. 8 However, to the best of our knowledge, a step-by-step microsurgical video illustration of this technique has not been previously published. Although this technique can be broadly used by neurosurgeons, irrespective of the hospital setting, it would be particularly valuable in settings where expensive cutting-edge technology is not readily available.

Background Cerebral bypass operation is a technically challenging operation that requires excellent surgical visibility and efficient ergonomics to minimize complications and maximize successful revascularization. Despite the operative microscope's utilization for the past two generations, there remains a need for continued improvement in operative visualization and surgical ergonomics. Objective To report the positives and negatives of our initial experience using a novel 4 K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX) for cranial bypass surgery. Methods A retrospective review over 6 mo was performed of all patients who have undergone cerebral bypass surgery at a single institution using the 4K-HD 3D EX. Advantages and disadvantages of the EX and clinical outcome of the patients were assessed. Results A total of 5 patients underwent cerebral EC-IC bypass surgery with no EX-related complications and successful revascularization. The lightweight design of the EX allowed for easy instrument maneuverability as well as uncomplicated surgical set up in the operating room. The assistance of the cosurgeon was significantly more efficient compared to that of the operating microscope. The large monitor allowed for an immersive, collaborative, and valuable educational surgical experience. Conclusion Using the EX for cerebral bypass surgery, with 3D ultra-high-definition optics, enhancements of ergonomics, and improved training, we believe that the 3D 4K-HD EX may represent the next generation of operative scopes in microneurosurgery.

During the past decade, Onyx® HD-500 (Medtronic Neurovascular, USA), a high-viscosity liquid embolic agent, has been used extensively to treat intracranial aneurysms. Preliminary experience using this relatively novel agent was rewarding in terms of high-occlusion rates and low-recanalization rates of large and wide-necked aneurysms [1, 2]. Use of Onyx HD-500 has since decreased dramatically with the increasing popularity of flow diverters as first-line treatment for complex intracranial aneurysms. Nevertheless, it remains a useful endovascular tool for select patients who are not good candidates for flow diversion because of recurrent stent-embolized aneurysms or nickel allergy.

Intraoperative neurophysiologic monitoring (IONM) is quickly gaining popularity across the full spectrum of neurosurgical subspecialties. It is particularly useful during brain aneurysm surgery, given its ability to detect cerebral ischemia in a timely manner. This electrophysiologic feedback provides the neurosurgeon with an opportunity to undertake corrective surgical actions before irreversible brain injury occurs. In this chapter, we offer a practical review of the various IONM modalities used in aneurysm surgery, their indications, advantages, and limitations.

Intracranial aneurysms may exhibit features that make them unsuitable for standard microsurgical and endovascular reconstructive strategies. For such lesions, deconstruction of the aneurysm and parent artery is often required, typically in association with a flow-replacement by pass procedure. The addition of a bypass helps minimize the risk of cerebral ischemia and infarction, particularly in the setting of subarachnoid hemorrhage (SAH). In this chapter, we present our management strategies for complex intracranial aneurysms and some of the technical nuances of microsurgical trapping and cerebral revascularization.

Cerebral venous thrombosis (CVT) is an uncommon cause of hemorrhagic stroke. A 47-year old woman presented with acute-onset global aphasia and right hemiplegia. Head CT revealed a large left frontoparietal hematoma with significant mass effect. Emergency decompressive hemicraniectomy and hematoma evacuation were thus indicated. Intraoperatively, an occlusive thrombus was identified in the superior anastomotic vein of Trolard, confirming the diagnosis of CVT. While hemorrhagic CVT is not a rare entity, the diagnosis is not usually made intraoperatively. More interestingly, the authors provide intraoperative photographs of the occlusive thrombus in the vein of Trolard, overlying the area of hemorrhage, which they believe are unique and compelling clinical images. Keywords: Cerebral venous thrombosis, Dural sinus thrombosis, Intracerebral hemorrhage, Superior anastomotic vein of Trolard, Thrombophilia, Venous infarction

Given its limited vascular territory, occlusion of the posterior cerebral artery (PCA) usually does not result in malignant infarction. Challenging this concept, we present 3 cases of unilateral PCA infarction with secondary malignant progression, resulting from extension into what would classically be considered the posterior middle cerebral artery (MCA) territory. Interestingly, these were true PCA infarctions, not "MCA plus" strokes, since the underlying occlusive lesion was in the PCA. We hypothesize that congenital and/or acquired variability in the distribution and extent of territory supplied by the PCA may underlie this rare clinical entity. Patients with a PCA infarction should thus be followed closely and offered early surgical decompression in the event of malignant progression.

Intracranial arterial aneurysms are an important cause of hemorrhagic stroke during the first two decades of life. In the pediatric population, intracranial arterial aneurysms have a diverse etiological spectrum. The clinical course, response to treatment and long-term prognosis correlate strongly with the mechanism of lesion pathogenesis. A variety of phenotypes have been characterized, having variably overlapping features and differentiated according to the mechanism of pathogenesis: (1) idiopathic, (2) traumatic, (3) infectious, (4) flow related, (5) oncotic, (6) non-infectious inflammatory, (7) arteriopathic and (8) familial. The purpose of this report is to review intracranial aneurysmal disease in the pediatric population. We discuss contemporary approaches to diagnostic evaluation and clinical management, emphasizing interventional strategies and recent advances.

Background During its development and preclinical assessment, a novel, 3-dimensional (3D), high-definition (4K-HD) exoscope system was formerly shown to provide an immersive surgical experience, while maintaining a portable, low-profile design. Objective To assess the clinical applicability of this 3D 4K-HD exoscope via first-in-man surgical use. Methods The operative workflow, functionality, and visual haptics of the 3D 4K-HD exoscope were assessed in a variety of microneurosurgical cases at 2 US centers. Results Nineteen microneurosurgical procedures in 18 patients were performed exclusively using the 3D 4K-HD exoscope. Pathologies treated included 4 aneurysms, 3 cavernous malformations (1 with intraoperative electrocorticography), 2 arteriovenous malformations, 1 foramen magnum meningioma, 1 convexity meningioma, 1 glioma, 1 occipital cyst, 1 chiari malformation, 1 carotid endarterectomy, 1 subdural hematoma, 1 anterior cervical discectomy and fusion, and 2 lumbar laminectomies. All patients experienced good surgical and clinical outcomes. Similar to preclinical assessments, the 3D 4K-HD exoscope provided an immersive 3D surgical experience for the primary surgeon, assistants, and trainees. The small exoscope frame, large depth of field, and hand/foot pedal controls improved exoscope mobility, decreased need to re-focus, and provided unobstructed operative corridors. Flexible positioning of the camera allows the surgeon's posture to be kept in a neutral position with uncompromised viewing angles. Conclusion The first-in-man clinical experience with the 3D 4K-HD exoscope confirms its excellent optics and ergonomics for the entire operative team, with high workflow adaptability for a variety of microneurosurgical cases. Expanded clinical use of the 3D 4K-HD exoscope is justified.

Background Ganglioglioma is a rare, benign, intraaxial glioneuronal tumor but a relatively common cause of pharmacoresistant temporal lobe epilepsy (TLE). Given its often nonspecific neuropsychiatric manifestations and frequently negative electroencephalographic workup, TLE can be easily misdiagnosed as a psychiatric disorder, particularly panic attacks. Case Description We present a case of a 17-year-old boy who was found to have lesional TLE secondary to a left temporal ganglioglioma, 5 years after having been misdiagnosed with panic disorder and having undergone ineffective and unnecessary psychotherapy. He was successfully cured by surgery. Although a few similar cases of TLE masquerading as a panic disorder have been previously reported in the literature, this is the youngest and only pediatric patient described to date. Conclusion This report underscores the challenges in making an accurate clinical diagnosis of TLE and the importance of timely brain imaging whenever an atypical or medically refractory panic disorder is encountered.

Although relatively rare, vertebral artery (VA) injuries are a source of significant morbidity and mortality after penetrating neck trauma and are frequently associated with cervical spine injuries. In addition to the risk of massive hemorrhage, partial VA injuries carry a significant risk of posterior circulation stroke. In contrast, total occlusion of a VA is generally well tolerated, with only 2–3 % risk of ischemic stroke due to poor collateral circulation. Therefore, VA sacrifice should always be considered if surgical or endovascular repair is not feasible. Patients presenting with active hemorrhage should undergo emergent surgical exploration and/or angiography to identify and repair the injured vessel. In contrast, stable patients should undergo a thorough physical examination followed by CTA. Endovascular treatment is generally preferred over surgery, given its low risk of complications, high technical success rate, and the possibility of stenting for vessel preservation. However, given the need for prolonged dual antiplatelet therapy, the decision to stent an acutely injured VA should be cautiously made. Nonhemorrhagic VA dissections are often managed with antithrombotic therapy, although the potential benefits of treatment should be carefully weighed against the hemorrhagic risks. Outcomes after penetrating neck trauma are typically determined by associated injuries, rather than the VA injury itself. Neurological deficits, in particular, are almost always due to direct spinal cord or nerve root damage, not posterior circulation stroke. Given recent advances in prehospital and critical care, as well as surgical and endovascular techniques, mortality rates following VA injury have significantly dropped, averaging 5–7 % in contemporary practice.

Object The role of endovascular therapy in patients with acute ischemic stroke and a solitary M2 occlusion remains unclear. Through a pooled analysis of 3 interventional stroke trials, the authors sought to analyze the impact of successful early reperfusion of M2 occlusions on patient outcome. Methods Patients with a solitary M2 occlusion were identified from the Prolyse in Acute Cerebral Thromboembolism (PROACT) II, Interventional Management of Stroke (IMS), and IMS II trial databases and were divided into 2 groups: successful reperfusion (thrombolysis in cerebral infarction [TICI] 2–3) at 2 hours and failed reperfusion (TICI 0–1) at 2 hours. Baseline characteristics and clinical outcomes were compared. Results Sixty-three patients, 40 from PROACT II and 23 from IMS and IMS II, were identified. Successful early angiographic reperfusion (TICI 2–3) was observed in 31 patients (49.2%). No statistically significant difference in the rates of intracerebral hemorrhage (60.9% vs 47.6%, p = 0.55) or mortality (19.4% vs 15.6%, p = 0.75) was observed. However, there was a trend toward higher incidence of symptomatic hemorrhage in the TICI 2–3 group (17.4% vs 0%, p = 0.11). There was also a trend toward higher baseline glucose levels in this group (151.5 mg/dl vs 129.6 mg/ dl, p = 0.09). Despite these differences, the rate of functional independence (modified Rankin Scale Score 0–2) at 3 months was similar (TICI 2–3, 58.1% vs TICI 0–1, 53.1%; p = 0.80). Conclusions A positive correlation between successful early reperfusion and clinical outcome could not be demonstrated for patients with M2 occlusion. Irrespective of reperfusion status, such patients have better outcomes than those with more proximal occlusions, with more than 50% achieving functional independence at 3 months.

The conventional technique of intracranial aneurysm embolization using Onyx HD-500 (ev3 Neurovascular, Irvine, CA, USA) involves repetitive balloon inflation-deflation cycles under general anesthesia. By limiting parent artery occlusion to 5 minutes, this cyclic technique is thought to minimize cerebral ischemia. However, intermittent balloon deflation may lengthen procedure time and allow balloon migration, resulting in intimal injury or Onyx leakage. We report our experience using a modified technique of uninterrupted Onyx injection with continuous balloon occlusion under conscious sedation. All Onyx embolization procedures for unruptured aneurysms performed by the senior author (A.J.R.) between September 2008 and April 2010 were retrospectively reviewed. Demographic, clinical, angiographic, and procedural data were recorded. Twenty-four embolization procedures were performed in 21 patients with 23 aneurysms, including four recurrences. Twenty aneurysms (87%) involved the paraclinoid or proximal supraclinoid internal carotid artery. Size ranged from 2.5 to 24 mm and neck diameter from 2 to 8 mm. The modified technique was employed in 19 cases. All but one patient (94.4%) tolerated continuous balloon inflation. Complete occlusion was achieved in 20 aneurysms (83.3%) and subtotal occlusion in three (12.5%). Stable angiographic results were seen in 85%, 94%, 94%, and 100% of patients at 6, 12, 24, and 36 months, respectively. There were no deaths. Permanent non-disabling neurological morbidity occurred in one patient (4.2%). Minor, transient, and/or angiographic complications were seen in three patients (12.5%), none related to the technique itself. Onyx embolization of unruptured intracranial aneurysms can be safely and effectively performed using continuous balloon inflation under conscious sedation.

Reversible cerebral vasoconstriction syndrome is a rare cause of headache and stroke in the pediatric population. Reversible vasoconstriction is reported in a 19-month-old girl with retinoblastoma who underwent selective ophthalmic artery infusion chemotherapy with melphalan. Procedure-related cerebral vasoconstriction was specifically triggered during coadministration of adjunctive medications, which included mydriatic eye drops containing phenylephrine, intranasal oxymetazoline, nebulized albuterol, intravenous hydrocortisone, and intravenous diphenhydramine. The course of cerebral vasospasm, which began with a severe hypertensive surge and resolved spontaneously within hours of blood pressure normalization, was documented by angiography in real time. Subsequent brain magnetic resonance imaging showed no evidence of perfusion abnormality, cerebral infarction, or cerebral hemorrhage, and the patient was discharged home without any neurologic sequelae. In this report, we highlight the potential risk of reversible cerebral vasoconstriction in children administered vasoactive drugs and discuss its relevance during treatment of retinoblastoma by intraarterial chemotherapy.

Objective/Background The use of antithrombotic medication (ATM) frequently is reported in patients with intracranial hemorrhage (ICH) and is associated with increased mortality. Unfortunately, ATMs sometimes are prescribed and/or used inappropriately. We sought to determine the rate of ATM misprescription/misuse among patients with ICH in a single-center retrospective study. Methods All patients admitted with ATM-related ICH in 1998−2014 were included. Charts were reviewed and demographic, clinical, and radiologic variables were recorded. The type of ATM, dose, and duration of treatment were analyzed critically. The adequacy of ATM prescription/use was assessed in light of the recommendations and guidelines of the American Heart Association, American Stroke Association, and French National Authority for Health, in effect at the time of admission. Results A total of 106 patients with mean age 68 years were identified. Aspirin (53.8%) was the most commonly used drug, followed by oral anticoagulants (31.1%) and clopidogrel (22.6%). In only 80 patients (75.5%), the use of ATM was in line with contemporary guidelines. In the remaining 26 (24.5%), the use of ATMs was inappropriate, including bad drug combination, wrong dose, poor indication, wrong drug class, and/or incorrect treatment duration. Conclusions In this Lebanese cohort of patients with ICH, the 24.5% rate of ATM misprescription and/or misuse is highly alarming and the origin of this problem is likely multifactorial. Immediate measures should be undertaken, and efforts should be focused on regaining tight control of ATM prescription and fulfillment, ensuring good patient education, and offering more vigilant oversight on physician licensure.

Object Although decompressive hemicraniectomy has been shown to reduce death and improve functional outcome following malignant middle cerebral artery territory infarction, there is ongoing debate as to whether surgery should be routinely performed, considering the very high rates of disability and functional dependence in survivors. Through a systematic review of the literature, the authors sought to determine the outcome from a patient's perspective. Methods In September 2010, a MEDLINE search of the English-language literature was performed using various combinations of 12 key words. A total of 16 papers were reviewed and individual study data were extracted. Results There was significant variability in study design, patient eligibility criteria, timing of surgery, and methods of outcome assessment. There were 382 patients (59% male, 41% female) with a mean age of 50 years, 25% with dominant-hemisphere infarction. The mortality rate was 24% and the mean follow-up in survivors was 19 months (range 3–114 months). Of 156 survivors with available modified Rankin Scale (mRS) scores, 41% had favorable functional outcome (mRS Score ≤ 3), whereas 47% had moderately severe disability (mRS Score 4). Among 157 survivors with quality of life assessment, the mean overall reduction was 45%: 67% for physical aspect and 37% for psychosocial aspect. Of 114 screened survivors, depression affected 56% and was moderate or severe in 25%. Most patients and/or caregivers (77% of the 209 interviewed) were satisfied and would give consent again for the procedure. Conclusions Despite high rates of physical disability and depression, the vast majority of patients are satisfied with life and do not regret having undergone surgery.

Malignant middle cerebral artery (MCA) infarctions are thought to be rare in children. In a recent hospital-based study, only 1.3 % of pediatric ischemic strokes were malignant MCA infarctions. However, population-based rates have not been published. We performed subgroup analysis of a population-based study to determine the rate of malignant MCA infarctions in children.In 2005 and 2010, all ischemic stroke-related emergency visits and hospital admissions among the 1.3 million residents of the five-county Greater Cincinnati/Northern Kentucky area were ascertained. Cases that occurred in patients 18 years and younger were reviewed in detail, and corresponding clinical and neuroimaging findings were recorded. Infarctions were considered malignant if they involved 50 % or more of the MCA territory and resulted in cerebral edema and mass effect.In 2005, eight pediatric ischemic strokes occurred in the study population, none of which were malignant infarctions. In 2010, there were also eight ischemic strokes. Of these, two malignant MCA infarctions were identified: (1) a 7-year-old boy who underwent hemicraniectomy and survived with moderate disability at 30 days and (2) a 17-year-old girl with significant prestroke disability who was not offered hemicraniectomy and died following withdrawal of care. Thus, among 16 children over 2 years, there were two malignant MCA infarctions (12.5 %, 95 % CI 0-29).Malignant MCA infarctions in children may not be as rare as previously thought. Given the significant survival and functional outcome benefit conferred by hemicraniectomy in adults, future studies focusing on its potential role in pediatric patients are warranted.

Cerebral arteriovenous malformations (AVMs) have been occasionally reported to bleed from their venous side. This may particularly be the case when venous ectasias or aneurysms develop in the setting of steno-occlusive venopathy. Venous side hemorrhage should be suspected when the hematoma is centered on the venous pouch or when a venous pseudoaneurysm is identified on angiography. For AVMs with an identifiable point of rupture, early treatment is recommended in an attempt to secure the weak spot and minimize the risk of rerupture. When possible, microsurgical resection is the definitive and preferred treatment. In contrast, because of its latency period, stereotactic radiosurgery does not confer immediate protection in such cases. Endovascular transarterial embolization may offer immediate cure to only a minority of small AVMs, but remains a very useful temporizing strategy for arterial rupture sites such as proximal or intranidal aneurysms, allowing to defer definitive AVM treatment by either microsurgery or radiosurgery to a later stage. However, when the rupture site is venous in location and the AVM cannot be readily cured by either microsurgery because of its location in eloquent brain or embolization because of its large size, protecting patients from early rerupture may become problematic. We propose that, by reducing flow through the AVM, transarterial embolization may lead to secondary thrombosis of venous pseudoaneurysms and confer durable occlusion of these weak spots, pending definitive AVM cure. Therefore, transarterial embolization should be routinely attempted in such difficult-to-manage cases. An illustrative clinical case is presented in support of this hypothesis.

Objectif: Il a ete bien demontre que l'hemicraniectomie decompressive (HD) diminue la mortalite chez les patients qui ont subi un infarctus malin dans le territoire de l'artere cerebrale moyenne (ACM). Plusieurs des patients qui survivent presentent une invalidite de moderee a severe. Il existe une controverse a savoir ce qui devrait etre considere comme etant un bon resultat. Nous avons evalue la qualite de vie (QV) de patients apres une HD effectuee suite a un infarctus malin dans le territoire de l'ACM dans notre milieu. Methode: Nous avons evalue le resultat chez tous les patients ayant subi une HD suite a un infarctus malin dans le territoire de l'ACM entre 2001 et 2009 au moyen d'une analyse retrospective de dossier et un suivi telephonique chez les survivants. Nous avons determine le resultat fonctionnel au moyen de la Glasgow outcome scale, de la modified Rankin scale (mRS) et du Bartel index (BI) et la QV au moyen de la Stroke Impact Scale. Resultats: Nous avons identifie 14 patients, 6 hommes et 8 femmes, dont l'âge moyen etait de 44 ans (ecart de 27 a 57 ans). Tous les patients avaient un niveau de conscience diminue avant la chirurgie. Cinq avaient subi un accident vasculaire cerebral de l'hemisphere dominant. L'intervalle median entre l'evenement et la chirurgie etait de 45 heures (ecart de 1 a 96 heures). Deux patients sont decedes et 1 patient n'a pas pu etre rejoint pour le suivi. Parmi les 11 survivants, l'issue fonctionnelle a ete favorable chez 7 patients (63,6%), soit un score mRS < 4. Aucun patient n'etait dans un etat vegetatif persistant. La majorite des patients dont nous avons fait l'entrevue et des soignants (7 de 8), incluant ceux qui avaient subi un AVC a l'hemisphere dominant, etaient satisfaits apres un suivi median de 18 mois (ecart de 6 a 43 mois) malgre une QV alteree, particulierement dans les domaines physiques. Conclusion: La plupart des patients rapportent une QV satisfaisante malgre une invalidite significative, meme ceux qui presentent une invalidite de moderee a severe et un AVC de l'hemisphere dominant. Un infarctus malin de l'ACM de l'hemisphere dominant ne devrait pas etre considere comme une contre-indication a l'HD.

While early rerupture of cerebral arteriovenous malformations (AVMs) may not be as rare as previously thought, its determinants and risk factors remain unknown. Impairment of the venous drainage of AVMs is a well known risk factor for rupture and has been linked with the development of perinidal cerebral edema. We propose that a significant proportion of early AVM reruptures are the result of post-hemorrhagic venous drainage impairment, which may manifest as refractory perihematomal edema. To support this hypothesis, an illustrative case of early AVM rerupture occurring 3 weeks following intracranial hemorrhage and heralded by progressive perinidal and perihematomal edema is presented. This finding should be viewed as a marker for unstable lesions with a high risk of imminent rerupture and should thus prompt a rapid definitive treatment for the AVM.

ObjectThe natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions.MethodsForty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32–59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared.ResultsThe study population consisted of 27 men and 14 women with a mean age of 54 years (range 24–78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0.ConclusionsFollowing lumbar discectomy, most patients develop Type 2 changes at the operated level, possibly as a result of accelerated degeneration in the operated disc. Neither the preoperative presence of MCs nor their postoperative course appears to affect the clinical outcome.

Meningeal melanocytoma is a rare benign CNS tumor derived from the leptomeningeal melanocytes. Although unusual, malignant transformation with leptomeningeal seeding into the brain or spinal cord may occur years after the initial diagnosis. The authors report a unique case of multifocal benign meningeal melanocytoma involving both cerebellopontine angles and the thoracic spinal cord, with associated diffuse leptomeningeal hyperpigmentation. They review the literature relevant to this topic and discuss the radiological and pathological features of this disease as well as its treatment options.

Background: Endoscopic third ventriculostomy (ETV) has gained wide popularity as a first-line treatment for obstructive hydrocephalus (OHC). We have been performing ETV since 1998. We report our experience with this technique in the management of OHC. Methods: Between 1998 and 2007, we performed 49 ETV procedures in 46 patients suffering from OHC. Medical records were retrospectively reviewed. Success was defined as shunt-free survival. Results: There were 29 males and 17 females with a mean age of 23 years (6 months–65 years). Aqueductal stenosis and tectal tumor were the most common etiologies (63%). Seven patients (15.6%) had early ETV failure. Of 38 patients with initial success and available follow-up, shunt independence was achieved in 29 patients (76.3%) after a mean follow-up of 37 months. Kaplan-Meier analysis yielded a 70% 5-year shunt-free survival rate. On multivariate analysis, no variables could predict early or late ETV failure. Transient complications occurred in 6 patients (13%), but there were no ETV-related deaths or permanent morbidity. Conclusion: ETV is a safe and effective treatment for OHC, resulting in a high rate of long-term shunt independence with a low risk of complications. ETV should be considered the treatment of choice for patients with OHC and its development as a substitute to shunt placement should be encouraged in neurosurgically developing countries.

To analyze the impact of the lunar cycle and season on the incidence of aneurysmal subarachnoid hemorrhage (SAH).The medical records of 111 patients who were admitted over a 5-year period to our department because of aneurysmal SAH were retrospectively reviewed. The date of aneurysm rupture was matched with the corresponding season and moon phase.An incidence peak for aneurysm rupture (28 patients) was seen during the phase of new moon, which was statistically significant (p0.001). In contrast, no seasonal variation in the incidence of SAH was observed.The lunar cycle seems to affect the incidence of intracranial aneurysm rupture, with the new moon being associated with an increased risk of aneurysmal SAH.

Background Ischemic stroke is being increasingly recognized as a possible cause of spontaneous isolated convexity subarachnoid hemorrhage (SAH). However, it is a much less established cause of cisternal, aneurysmal-like SAH. Only 3 case reports of concomitant cisternal SAH and perforator infarcts exist in the literature, raising the possibility of perforating artery rupture as a potential mechanism. In contrast, embolic stroke is not recognized as a cause of aneurysmal-like SAH. Case Description In 2 patients with embolic cerebral infarctions mimicking intracranial aneurysm rupture, diagnosis was confirmed by magnetic resonance imaging with diffusion-weighted imaging after cerebral angiography failed to reveal an underlying vascular lesion. Extracranial atherosclerosis was identified as the source of emboli in each case. One patient was started on antiplatelet therapy, and the other underwent surgical revascularization. Both patients had a favorable hospital course, with no recurrent hemorrhage or ischemia. Conclusions Based on these observations, embolic stroke should be included in the differential diagnosis of angiogram-negative SAH. Therefore, brain magnetic resonance imaging and vascular imaging of the neck should be part of the routine work-up of this relatively common entity.

Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death.

Background and Purpose— The role of endovascular therapy for acute M2 trunk occlusions is debatable. Through a subgroup analysis of Prolyse in Acute Cerebral Thromboembolism-II, we compared outcomes of M2 occlusions in treatment and control arms. Methods— Solitary M2 occlusions were identified from the Prolyse in Acute Cerebral Thromboembolism-II database. Primary endpoints were successful angiographic reperfusion (TICI 2–3) at 120 minutes and functional independence (mRS 0–2) at 90 days. Results— Forty-four patients with solitary M2 occlusions, 30 in the treatment arm and 14 in the control arm, were identified. Successful reperfusion (TICI 2–3) was achieved in 53.6% and 16.7% of patients in the treatment and control arms, respectively ( P =0.04). A favorable clinical outcome (mRS 0–2) was observed in 53.3% and 28.6%, respectively ( P =0.19). Baseline characteristics were similar between the 2 groups. Conclusions— Intra-arterial thrombolysis may lead to a 3-fold increase in the rate of early reperfusion of solitary M2 occlusions and could potentially double the chance of a favorable functional outcome at 90 days. Clinical Trial Registration— This trial was not registered because enrollment began before July 1, 2005.