Marc R. Daou

The Role of Simulation in Neurosurgical Education: A Survey of 99 United States Neurosurgery Program Directors

OBJECTIVE With the reduction of resident work hours and the increasing focus on patient safety, it has become evident that simulation has a growing role to play in surgical education. We surveyed the program directors of 99 U.S. Neurosurgery programs in an effort to better understand how simulation can be implemented in Neurosurgery and to gain insight into key issues that are currently being discussed amongst Neurosurgical educators. METHODS A 14-item questionnaire was emailed to 99 Neurosurgery residency program directors. Questions assessed the clinical impact of simulation, the role of simulation in academia, the investments required in time and money, and the model best suited for simulation. RESULTS The survey response rate was 53.5%. Seventy-two percent of respondents believed that simulation would improve patient outcome, 74% that it could supplement conventional training, but only 25% that it could replace it. The majority strongly believed that it could help preparing complex cases and could be of use to attending faculty. Forty-five percent thought that residents should achieve pre-defined levels of proficiency on simulators before working on patients. Seventy-four percent of respondents declared they would make simulator practice mandatory if available, and the majority was willing to invest daily time and considerable funds on simulators. Cadavers were the least preferred models to use compared to virtual simulation and noncadaveric physical models. CONCLUSIONS Simulation should be integrated in Neurosurgery training curricula. The validation of available tools is the next step that will enable the training, acquisition, and testing of neurosurgical skills.

De novo large fusiform posterior circulation intracranial aneurysm presenting with subarachnoid hemorrhage 7 years after therapeutic internal carotid artery occlusion: case report and review of the literature.

BACKGROUND AND IMPORTANCE Although the use of proximal artery occlusion, or hunterian ligation, for the treatment of intracranial aneurysms has decreased greatly over the past decades, this approach still finds use for certain giant and complex aneurysms. The main risks of artery sacrifice are ischemic complications but also, although rare, de novo aneurysm formation. We present here a case of de novo formation of a large fusiform basilar artery aneurysm 7 years after internal carotid artery occlusion. CLINICAL PRESENTATION A 17-year-old male patient with a history of a giant right cavernous aneurysm treated 7 years earlier with right-sided endovascular internal carotid artery occlusion presented to our institution with a thunderclap headache. At the time of initial evaluation, the patient was neurologically intact and imaging revealed a 22 × 10-mm fusiform aneurysm of the distal basilar artery with mass effect on the adjacent pons as well as a small amount of subarachnoid and intraventricular blood. Complete occlusion of the right internal carotid artery was demonstrated with retrograde filling of the right middle cerebral artery from the enlarged right posterior communicating artery. The patient was subsequently treated with hunterian occlusion of the basilar artery below anterior inferior cerebellar arteries. A superficial temporal artery to middle cerebral artery bypass was performed on the right side before this occlusion. CONCLUSION Further studies on the epidemiology of de novo aneurysms after carotid artery occlusion are warranted. Patients at higher risk of the development of intracranial aneurysms should be followed aggressively after hunterian ligation, and the possibility of an extracranial-intracranial bypass should be discussed.

Intracranial Aneurysms in Previously Irradiated Fields: Literature Review and Case Report

OBJECTIVE Radiotherapy is a common treatment for a variety of disease processes in the central nervous system; it has an ever-increasing number of indications and applications. With the life expectancy of cancer patients increasing, delayed complications of radiation have become more apparent. One such potential complication is the appearance of intracranial aneurysms in the irradiated field. The incidence and natural history of these aneurysms is not well understood. To this end, we performed a review of the literature to analyze the current state of knowledge of these rare aneurysms. Furthermore, we present a case treated at our center. METHODS We reviewed the literature for all reported cases of intracranial aneurysms appearing in an irradiated field, including any available histopathologic analysis. All papers were included irrespective of the language in which it was published. We calculated the mean age at radiation exposure, the interval between radiation exposure, and aneurysm development and the rate of presentation. Herein we also present a case of an intracranial aneurysm in a 38-year-old patient detected in an irradiation field 33 years after the patient underwent craniospinal irradiation for a medulloblastoma. RESULTS A total of 46 patients with 69 intracranial aneurysms in irradiation fields were reported between 1978 and 2013. The mean age at radiation exposure was 34 years, and the mean lag time between exposure and diagnosis was 12 years (range, 4 months to 50 years). The median lag time between exposure and diagnosis was shorter in patients older than 40 (6 years). Among the reported aneurysms, 83% were saccular, 9% were fusiform, and 9% were considered pseudo-aneurysms. The Median lag time was 20 years for brachytherapy, 8 years for focused radiation, 9 years for whole brain radiation, and 6 years for SRS. Among reported aneurysms, 55% presented with some form of hemorrhage: intracranial rupture with subarachnoid hemorrhage, epistaxis, or otorrhagia. Only 13% were discovered on routine follow-up or were found incidentally for work-up of unrelated neurologic symptoms. CONCLUSION Although rarely reported, intracranial aneurysms in irradiation fields may warrant special attention when diagnosed. These aneurysms may have an inherently weaker structure and may be more prone to rupture. Their repair may also be complicated by more fragile and irregular morphology. The increasing longevity of cancer patients suggests that screening for aneurysms at irradiation sites may be warranted, but further studies are needed to validate this approach.

A Didactic and hands-on module enhances resident microsurgical knowledge and technical skill

BACKGROUND Simulation has been adopted as a powerful training tool in many areas of health care. However, it has not yet been systematically embraced in neurosurgery because of the absence of validated tools, assessment scales, and curricula. OBJECTIVE To use our validated microanastomosis module and scale to evaluate the effects of an educational intervention on the performance of neurosurgery residents at the 2012 Congress of Neurological Surgeons Annual Meeting. METHODS The module consisted of an end-to-end microanastomosis of a 3-mm vessel and was divided into 3 phases: (1) a cognitive and microsuture prelecture testing phase, (2) a didactic lecture, and (3) a cognitive and microsuture postlecture testing phase. We compared resident knowledge and technical proficiency from the pretesting and posttesting phases. RESULTS One neurosurgeon and 7 neurosurgery residents participated in the study. None had previous experience in microsurgery. The average score on the microsuture prelecture and postlecture tests, as measured by our assessment scale, was 32.50 and 39.75, respectively (P = .001). The number of completed sutures at the end of each procedure was higher for 75% of participants in the postlecture testing phase (P = .03). The average score on the cognitive postlecture test (12.75) was significantly better than that of the cognitive prelecture test (8.38; P = .001). CONCLUSION Simulation has the potential to enhance resident education and to elevate proficiency levels. Our data suggest that a focused microsurgical module that incorporates a didactic component and a technical component can enhance resident knowledge and technical proficiency in microsurgical anastomosis.BACKGROUND Simulation has been adopted as a powerful training tool in many areas of health care. However, it has not yet been systematically embraced in neurosurgery because of the absence of validated tools, assessment scales, and curricula. OBJECTIVE To use our validated microanastomosis module and scale to evaluate the effects of an educational intervention on the performance of neurosurgery residents at the 2012 Congress of Neurological Surgeons Annual Meeting. METHODS The module consisted of an end-to-end microanastomosis of a 3-mm vessel and was divided into 3 phases: (1) a cognitive and microsuture prelecture testing phase, (2) a didactic lecture, and (3) a cognitive and microsuture postlecture testing phase. We compared resident knowledge and technical proficiency from the pretesting and posttesting phases. RESULTS One neurosurgeon and 7 neurosurgery residents participated in the study. None had previous experience in microsurgery. The average score on the microsuture prelecture and postlecture tests, as measured by our assessment scale, was 32.50 and 39.75, respectively (P = .001). The number of completed sutures at the end of each procedure was higher for 75% of participants in the postlecture testing phase (P = .03). The average score on the cognitive postlecture test (12.75) was significantly better than that of the cognitive prelecture test (8.38; P = .001). CONCLUSION Simulation has the potential to enhance resident education and to elevate proficiency levels. Our data suggest that a focused microsurgical module that incorporates a didactic component and a technical component can enhance resident knowledge and technical proficiency in microsurgical anastomosis.

A pilot study to assess the construct and face validity of the Northwestern Objective Microanastomosis Assessment Tool

OBJECT Microsurgical skills remain an integral component of neurosurgical education. There is a need for an objective scale to assess microsurgical skills. The objective of this study was to assess the face and construct validity of a bench training microanastomosis module and an objective assessment scale, i.e., the Northwestern Objective Microanastomosis Assessment Tool (NOMAT). METHODS Medical students, neurosurgical residents, and postdoctoral research fellows at Northwestern University were enrolled in the study. Trainees were divided into 3 groups based on microsurgical experience: 1) experienced, 2) exposed, and 3) novices. Each trainee completed two end-to-end microanastomoses using a 1-mm and a 3-mm synthetic vessel. Two cameras were installed to capture procedural footage. One neurosurgeon blindly graded the performance of trainees using both objective and subjective methods to assess construct validity. Two neurosurgeons reviewed the contents of the simulation module to assess face validity. RESULTS Twenty-one trainees participated in the study, including 6 experienced, 6 exposed, and 9 novices. The mean NOMAT score for experienced trainees on the 1-mm module was 47.3/70 compared with 26.0/70 and 25.8/70 for exposed and novice trainees, respectively (p = 0.02). Using subjective grading, experienced trainees performed significantly better on the 1-mm module (64.2/100) compared with exposed or novice trainees (23.3/100 and 25.0/100, respectively; p = 0.02). No statistical difference between groups was noted for the 3-mm module with both NOMAT and subjective grading. Experienced trainees took less time to perform both tasks compared with the others. CONCLUSIONS Face and construct validities of the microanastomosis module were established. The scale and the microanastomosis module could help assess the microsurgical skills of neurosurgical trainees and serve as a basis for the creation of a microsurgical curriculum.

Surgical Treatment of Elevated Intracranial Pressure: Decompressive Craniectomy and Intracranial Pressure Monitoring

Surgical techniques that address elevated intracranial pressure include (1) intraventricular catheter insertion and cerebrospinal fluid drainage, (2) removal of an intracranial space-occupying lesion, and (3) decompressive craniectomy. This review discusses the role of surgery in the management of elevated intracranial pressure, with special focus on intraventricular catheter placement and decompressive craniectomy. The techniques and potential complications of each procedure are described, and the existing evidence regarding the impact of these procedures on patient outcome is reviewed. Surgical management of mass lesions and ischemic or hemorrhagic stroke occurring in the posterior fossa is not discussed herein.

New-generation oral anticoagulants for the prevention of stroke: Implications for neurosurgery

A new generation of oral anticoagulants, namely direct thrombin inhibitors and factor Xa inhibitors, have recently been approved for clinical use in patients with atrial fibrillation. These novel families of drugs have been shown to have favorable efficacy and safety profiles in multiple clinical settings, particularly in the prevention of atrial fibrillation-related stroke, and are likely to become part of everyday practice, making a crossover to neurosurgical patients inevitable. Concern has risen regarding the complexity of managing intracranial and intraspinal hemorrhages related to these drugs. This review aims to provide an update on the most recent advances in oral anticoagulant drug therapy from a neurosurgeons perspective. We discuss current evidence for the use of these novel agents, their limitations, existing methods of drug-level monitoring, and controversies related to anticoagulation reversal. We also discuss specific topics such as anticoagulation resumption after intracranial or intraspinal bleeding, perioperative anticoagulant administration, and the possibility of combination with tissue plasminogen activator in the setting of acute ischemic stroke. A special focus is given to the incidence of intracranial and intraspinal hemorrhage associated with each drug.

Novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty

We describe the novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty. Cerebral venous sinus thrombosis is a rare disease that is usually treated with medical anticoagulation. In certain refractory cases, surgical or endovascular thrombolysis and thrombectomy may be required. A 48 year-old man on anticoagulation for cerebral venous sinus thrombosis presented with nausea, vomiting and worsening hemiparesis. The patient underwent endovascular venous sinus thrombolysis and venoplasty with continuous in situ tissue plasminogen activator (tPA) infusion over 48 hours. This novel approach to the endovascular treatment of venous sinus thrombosis, including the use of a double lumen balloon was advantageous, as it allowed direct infusion of tPA through the balloon catheter without having to exchange the balloon for a microcatheter.

Unruptured intracranial aneurysms: risk factors and their interactions.

thors use a few exemplar tasks, taking the reader through the model’s functioning. For instance, during the A3 working memory task, Spaun is required to store a sequence of symbolic images into a visually based firing pattern, and then use the subcortical network (including the striatum to produce decoded possible actions, and the GPi for action selection) to reproduce the stored memory images. Raster plots of the network activity are shown in the Figure. The authors demonstrate similar results with all eight tasks explored with Spaun. Novel aspects of this modeling effort include the ability to solve different classes of tasks with a coordinated set of neural substrates in a fashion that can be used to form testable hypotheses. The solution for the rapid variable creation task (A6, above) implemented by Spaun, for instance, is novel and may very well differ in a measurable fashion from the human analog. In summary, Eliasmith et al have developed a computational spiking neuron model of the brain capable of supporting a series of cognitive tasks incorporating sensory inputs and motor outputs. The power of this effort, and in similar brain modeling studies, lies in the ability of the model to summarize known electrophysiology and cognitive behavior and then compare this behavior with experiment. Similar models incorporating pathologies of connectivity or abnormal neuronal firing would be very useful for designing functional neurostimulation therapies or provide clues for therapeutic targets.

Higher Prehospital Priority Level for Stroke Makes Sense: The Hyper Acute STroke Alarm (HASTA) Study

troke is the second most common cause of death worldwide and the leading cause of disability in the United S States (4). Major advances in the medical, surgical, and interventional approaches to stroke therapy have occurred in the past two decades, yet many patients still do not reach the appropriate clinical setting in a timely fashion (2, 3). How patients are triaged by the emergency medical system from time of first emergency call could determine how quickly they reach appropriate medical care. In Sweden, the priority level assigned to stroke patients is two—an ambulance should reach a stroke patient in less than 30 minutes unless it is needed for a priority one event. Priority one events are defined as imminently lifethreatening events such as severe burns and heart attacks. Although this classification may seem intuitive in limitedresource scenarios, it may not ensure optimum allocation of resources and optimal outcomes.