Faculty Bibliography

BACKGROUND: Subarachnoid hemorrhage (SAH) due to intracranial aneurysm rupture is a major neurosurgical emergency associated with significant morbidity and mortality. Rapid aneurysm growth is associated with rupture. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disorder whose complications can include cerebral vasculitis and vasculopathy. Intracranial aneurysms are not known to occur more frequently in SLE patients than the general population; however, aneurysm growth rates have not been studied in SLE. CASE DESCRIPTION: We present a 43-year-old female with SLE on prednisone, hydroxychloroquine, and azathioprine with moderate disease activity who presented with severe, acute-onset headache and was found to have Hunt and Hess grade II SAH due to rupture of an 8 mm saccular anterior communicating artery (ACoA) aneurysm. The patient developed severe vasospasm, re-ruptured, and was taken for angiography and embolization, which was challenging due to a high degree of vasospasm and arterial stenosis. Review of imaging from less than 2 years prior demonstrated a normal ACoA complex without evidence of an aneurysm. CONCLUSION: We review the literature and discuss the risk factors and pathophysiology of rapid aneurysm growth and rupture, as well as the pathologic vascular changes associated with SLE. Although SLE patients do not develop intracranial aneurysm at an increased rate, these changes may predispose them to higher incidence of growth and rupture. This possibility-coupled with increased morbidity and mortality of SAH in SLE-suggests that SAH should be considered in SLE patients presenting with headache, and advocates for more aggressive treatment of SLE patients with unruptured aneurysms.

Introduction: Disconjugate eye movements have been associated with traumatic brain injury since ancient times. Ocular motility dysfunction may be present in up to 90% of patients with concussion or blast injury. Methods: We developed an algorithm for eye tracking in which the Cartesian coordinates of the right and left pupils are tracked over 200 seconds and compared to each other as a subject watches a short film clip moving inside an aperture on a computer screen. We prospectively eye tracked 64 normal healthy non-injured control subjects and compared findings to 75 trauma subjects with either a positive head CT (n=13), negative head CT (n=39) or non-head injury (n=23) to determine whether eye tracking would reveal the disconjugate gaze associated with both structural brain injury and concussion. Tracking metrics were then correlated to the clinical concussion measure SCAT3 in trauma patients. Results: Five out of five measures of horizontal disconjugacy were increased in positive and negative head CT patients relative to non-injured control subjects. Only one of five vertical disconjugacy measures was significantly increased in brain injured patients relative to controls. Linear regression analysis of all 75 trauma patients demonstrated that three metrics for horizontal disconjugacy negatively correlated with SCAT3 symptom severity score and positively correlated with total Standardized Assessment of Concussion (SAC) score. Abnormal eye tracking metrics improved over time towards baseline in brain injured subjects seen in follow-up. Conclusions: Eye tracking may help quantify the severity of ocular motility disruption associated with concussion and structural brain injury.

OBJECT Physicians are often solicited by patients or colleagues for clinical recommendations they would make for themselves if faced by a clinical situation. The act of making a recommendation can alter the clinical course being taken. The authors sought to understand this dynamic across different neurosurgical scenarios by examining how neurosurgeons value the procedures that they offer. METHODS The authors conducted an online survey using the Congress of Neurological Surgeons listserv in May 2013. Respondents were randomized to answer either as the surgeon or as the patient. Questions encompassed an array of distinct neurosurgical scenarios. Data on practice parameters and experience levels were also collected. RESULTS Of the 534 survey responses, 279 responded as the "neurosurgeon" and 255 as the "patient." For both vestibular schwannoma and arteriovenous malformation management, more respondents chose resection for their patient but radiosurgery for themselves (p = 0.002 and p = 0.001, respectively). Aneurysm coiling was chosen more often than clipping, but those whose practice was >/= 30% open cerebrovascular neurosurgery were less likely to choose coiling. Overall, neurosurgeons who focus predominantly on tumors were more aggressive in managing the glioma, vestibular schwannoma, arteriovenous malformation, and trauma. Neurosurgeons more than 10 years out of residency were less likely to recommend surgery for management of spinal pain, aneurysm, arteriovenous malformation, and trauma scenarios. CONCLUSIONS In the majority of cases, altering the role of the surgeon did not change the decision to pursue treatment. In certain clinical scenarios, however, neurosurgeons chose treatment options for themselves that were different from what they would have chosen for (or recommended to) their patients. For the management of vestibular schwannomas, arteriovenous malformations, intracranial aneurysms, and hypertensive hemorrhages, responses favored less invasive interventions when the surgeon was the patient. These findings are likely a result of cognitive biases, previous training, experience, areas of expertise, and personal values.

OBJECT Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect. METHODS The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects. RESULTS In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value +/- SD of 1.0117 +/- 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 +/- 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases. CONCLUSIONS This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.

INTRODUCTION: It is known that physicians sometimes recommend treatment that, in a similar clinical scenario, they might not choose for themselves. We sought to understand this dynamic across cerebrovascular practice and examine how neurosurgeons value the procedures they offer. METHODS: We conducted an online survey sent to a large cohort of neurosurgeons in May 2013. Respondents were randomised to answer either as the surgeon or as the patient. The questions involved patients presenting with 1) an epidural hematoma (control), 2) un-ruptured anterior communicating artery aneurysm, 3) incidentally found right temporal AVM, 4) spontaneous intracranial and intraventricular haemorrhage in deep structure. Data on practice parameters and experience levels was also collected. RESULTS: We obtained 534 survey responses, 279 responding as the "neurosurgeon", and 255 as the "patient," with a response rate of 19.7%. Demographics amongst the two groups of survey takers was similar. There was no difference in the management of an epidural hematoma, as expected. For the unruptured aneurysm, the rates of opting for treatment was similar amongst respondees. However within the treatment group there was a trend for survey takers to more often chose coiling for themselves and clipping for patients (p = 0.056). Surgeons, however, with a greater than 30% open-cerebrovascular practice had less of a tendency to do so. For arteriovenous malformation management, there was no statistical difference between choosing treatment or conservative management. However, amongst the respondees who chose treatment, more respondees chose resection/embolization for their patient but radiosurgery for self (p = 0.001). In a case of a large spontaneous intracranial and intraventricular haemorrhage neurosurgeons were more likely to place a ventricular drain in a patient than himself or herself. Neurosurgeons in practice more than 10 years since residency were more likely to recommend against interventions for aneurysms, AVMs or intracranial haemorrhage. CONCLUSIONS: In the majority of cases altering the role of the surgeon did not change the decision to pursue treatment or conservative treatment. In certain clinical scenarios, however, neurosurgeons choose treatment options for themselves that are different than what they would choose for their patients. For the management of an arteriovenous malformations, intracranial aneurysms, and hypertensive haemorrhage, responses favored less invasive interventions when the surgeon was the patient. These findings are likely a result of cognitive biases, previous training, experience, areas of expertise, and personal values. DISCLOSURES: O. Tanweer: None. T. Wilson: None. S. Kalhorn: None. J. Golfinos: None. P. Huang: None. D. Kondziolka: None.

BACKGROUND: Extracranial-intracranial (EC-IC) bypass and intracranial stenting (ICS) are both revascularization procedures that have emerged as treatment options for intracranial atherosclerotic disease (ICAD). This study describes and compares recent trends in utilization and outcomes of intracranial revascularization procedures in the United States using a population-based cohort. It also investigates the association of ICS and EC-IC bypass with periprocedural morbidity and mortality, unfavorable discharge status, length of stay (LOS), and total hospital charges. METHODS: The National Inpatient Sample (NIS) was queried for patients with ICAD who underwent EC-IC bypass or ICS during the years 2004-2010. Patient characteristics, demographics, perioperative complications, outcomes, and discharge data were collected. RESULTS: There were 627 patients who underwent ICS and 249 patients who underwent EC-IC bypass. Patients who underwent ICS were significantly older (P < 0.001) with more comorbidities (P = 0.027) than those who underwent EC-IC bypass. Patients who underwent EC-IC bypass experienced higher rates of postprocedure stroke (P = 0.014), but those who underwent ICS experienced higher rates of death (P = 0.006). Among asymptomatic patients, the rates of postprocedure stroke (P = 0.341) and death (P = 0.887) were similar between patients who underwent ICS and those who underwent EC-IC bypass. Among symptomatic patients, however, there was a higher rate of postprocedure stroke in patients who underwent EC-IC bypass (P < 0.001) and a higher rate of death among patients who underwent ICS (P = 0.015). CONCLUSION: The ideal management of patients with ICAD cannot yet be defined. Although much data from randomized and prospective trials on revascularization have been collected, many questions remain unanswered. There still remain cohorts of patients, specifically patients who have failed aggressive medical management, where not enough evidence is available to dictate decision-making. In order to further elucidate the safety and efficacy of these intracranial revascularization procedures, further clinical trials are needed.

BACKGROUND AND PURPOSE: Although there is generally thought to be a 2% to 4% per annum rupture risk for brain arteriovenous malformations (bAVMs), there is no way to estimate risk for an individual patient. METHODS: In this retrospective study, patients were eligible who had nidiform bAVMs and underwent detailed pretreatment diagnostic cerebral angiography at our medical center from 1996 to 2006. All patients had superselective microcatheter angiography, and films were reviewed for the purpose of this project. Patient demographics, clinical presentation, and angioarchitectural characteristics were analyzed. A univariate analysis was performed, and angioarchitectural features with potential physiological significance that showed at least a trend toward significance were added to a multivariate logistic regression model. RESULTS: One hundred twenty-two bAVMs met criteria for study entry. bAVMs with single venous drainage anatomy were more likely to present with hemorrhage. In addition, patients with multiple draining veins and a venous stenosis reverted to a risk similar to those with 1 draining vein, whereas those with multiple draining veins and without stenosis had diminished association with hemorrhage presentation. Those bAVMs with associated aneurysms were more likely to present with hemorrhage. These findings were robust in both univariate and multivariate models. CONCLUSIONS: The results of this article lead to the first physiological, internally consistent model of individual bAVM hemorrhage risk, where 1 draining vein, venous stenosis, and associated aneurysms increase risk.

SUMMARY:Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments - cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus - are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.

BACKGROUND: Flexion-extension radiographs are often used to assess for removal of the cervical collar in the setting of trauma. The objective of this study was to evaluate their adequacy. We hypothesized that a significant proportion is inadequate. METHODS: This was a retrospective review of C-spine clearance at a level 1 trauma center. A trauma-trained radiologist interpreted all flexion-extension radiographs for adequacy. Studies performed within 7 days of injury were considered acute. RESULTS: Three hundred fifty-five flexion-extension radiographs were examined. Ninety-five percent% of these studies were inadequate (51% because of the inability to visualize the top of T1, whereas 44% had less than 30 degrees of angulation from neutral). Two hundred ten studies were performed acutely; of these, 97% were inadequate. When performed 7 days or longer from injury, 91% were inadequate. CONCLUSIONS: Injury to the C-spine may harbor significant consequences; therefore, its proper evaluation is critical. The majority of flexion-extension films are inadequate. As such, they should not be included in the algorithm for removal of the cervical collar. If used, adequacy must be verified and supplemental radiographic studies obtained as indicated.

Object Patients undergoing placement of an external ventricular drain (EVD) are at increased risk for development of venous thromboembolisms (VTEs). Early chemical prophylaxis has been shown to decrease rates of embolism formation, but the risks for bleeding and the optimal time to initiate prophylaxis have not been clearly defined for this patient population. The authors evaluated the safety and risks for bleeding when chemical prophylaxis for VTEs was started within 24 hours of EVD placement. Methods To compare rates of hemorrhage among patients who received prophylaxis within 24 hours and those who received it later than 24 hours after admission, the authors conducted an institutional review board-approved retrospective review. Patients were those who had had an EVD placed and postprocedural imaging conducted at Bellevue Hospital, New York, from January 2009 through April 2012. Data collected included demographics, diagnosis, coagulation panel results, time to VTE prophylaxis and imaging, and occurrence of VTEs. The EVD-associated hemorrhages were classified as Grade 0, no hemorrhage; Grade 1, petechial hyperdensity near the drain; Grade 2, hematoma of 1-15 ml; Grade 3, epidural or subdural hematoma greater than 15 ml; or Grade 4, intraventricular hemorrhage or hematoma requiring surgical intervention. Results Among 99 patients, 111 EVDs had been placed. Low-dose unfractionated heparin had been given within 24 hours of admission (early prophylaxis) to 56 patients and later than 24 hours after admission (delayed prophylaxis) to 55 patients. There were no statistical differences across all grades (0-4) among those who received early prophylaxis (n = 45, 5, 5, 1, and 0, respectively) and those who received delayed prophylaxis (n = 46, 4, 1, 1, and 3, respectively) (p = 0.731). In the early prophylaxis group, 3 VTEs were discovered among 32 of 56 patients screened for clinically suspected VTEs. In the delayed prophylaxis group, 5 VTEs were discovered among 33 of 55 patients screened for clinically suspected VTEs (p = 0.71). Conclusions Hemorrhagic complications did not increase when chemical prophylaxis was started within 24 hours of admission. Also, the incidence of VTEs did not differ between patients in the early and delayed prophylaxis groups. Larger randomized controlled trials are probably needed to assess decreases in VTEs with earlier prophylaxis.