Allan D. Nanney

Development of venous thromboembolism (VTE) in patients undergoing surgery for brain tumors: Results from a single center over a 10 year period

Patients who undergo craniotomy for brain neoplasms have a high risk of developing venous thromboembolism (VTE), including deep vein thromboses (DVT) and pulmonary emboli (PE). The reasons for this correlation are not fully understood. This retrospective, single-center review aimed to determine the risk factors for VTE in patients who underwent neurosurgical resection of brain tumors at Northwestern University from 1999 to 2010. Our cohort included 1148 patients, 158 (13.7%) of whom were diagnosed with DVT and 38 (3.3%) of whom were diagnosed with PE. A variety of clinical factors were studied to determine predictors of VTE, including sex, ethnicity, medical co-morbidities, surgical positioning, length of hospital stay, tumor location, and tumor histology. Use of post-operative anticoagulants and hemorrhagic complications were also investigated. A prior history of VTE was found to be highly predictive of post-operative DVT (odds ratio [OR]=7.6, p=0.01), as was the patients sex (OR=14.2, p<0.001), ethnicity (OR=0.5, p=0.04), post-operative intensive care unit days (OR=0.2, p=0.003), and tumor histology (OR=-0.16, p=0.01). Contrary to reports in the literature, the data collected did not indicate that the administration of post-operative medical prophylaxis for VTE was significant in preventing their formation (OR=-0.14, p=0.76). Hemorrhagic complications were low (2.2%) and resultant neurologic deficit was lower still (0.7%). The study indicates that patients with high-grade primary brain tumors and metastatic lesions should receive aggressive preventative measures in the post-operative period.

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.

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.

Low-Dose Gamma Knife Radiosurgery for Vestibular Schwannomas: Tumor Control and Cranial Nerve Function Preservation After 11 Gy

Objectives This study aims to report tumor control rates and cranial nerve function after low dose (11.0 Gy) Gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas. Methods A retrospective chart review was performed on 30 consecutive patients with vestibular schwannomas treated from March 2004 to August 2010 with GKRS at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. The marginal dose for all patients was 11.0 Gy prescribed to the 50% isodose line. Median follow‐up time was 42 months. The median treatment volume was 0.53 cm3. Hearing data were obtained from audiometry reports before and after radiosurgery. Results The actuarial progression free survival (PFS) based on freedom from surgery was 100% at 5 years. PFS based on freedom from persistent growth was 91% at 5 years. One patient experienced tumor progression requiring resection at 87 months. Serviceable hearing, defined as Gardner‐Robertson score of I‐II, was preserved in 50% of patients. On univariate and multivariate analyses, only higher mean and maximum dose to the cochlea significantly decreased the proportion of patients with serviceable hearing. Conclusion Vestibular schwannomas can be treated with low doses (11.0 Gy) of GKRS with good tumor control and cranial nerve preservation.

Use of a harvested radial artery graft with preservation of the vena comitantes to reduce spasm risk and improve graft patency for extracranial to intracranial bypass: Technical note

BACKGROUND AND SIGNIFICANCE The vessels of choice for cerebrovascular high-flow direct bypass procedures are the radial artery and the saphenous vein. Radial artery grafts have become favored over saphenous vein grafts because of higher patency rates and better size matching to appropriate recipient vessels. Radial grafts are prone to spasm however, and this may be seen in 4-10% of cases and can be associated with ischemic sequelae. The standard technique for radial artery harvest calls for complete separation of the artery from its adventitial attachments and associated venous network. There is reason to believe that this could contribute to spasm risk and possibly even thrombosis. Radial graft outcomes appear to be improved when the vena comitantes is preserved in cardiac and peripheral applications. We report the novel use of a harvested radial artery graft with preservation of its venae comitantes for extracranial to intracranial bypass. CLINICAL PRESENTATION The patient is a 59-year-old male who had a blunt head trauma with associated loss of consciousness and who was led to the incidental discovery of a large fusiform middle cerebral artery (MCA) aneurysm. CONCLUSION Preservation of the vena comitantes when harvesting a radial arterial graft for bypass, along with dual (arterial and venous) anastomoses, and concomitant use of intra-operative vaso-dilatory maneuvers to prevent spasm, may improve overall graft patency and patient outcome.

Stroke: a global killer on the rise.

How a disease ranks vis-a-vis morbidity and mortality will dictate the allocation of clinical and research resources. This ranking can define strategic planning for national and international health organizations as well as biomedical corporations. With ever diminishing resources, the need to understand healthcare priorities and reduce disease burden on society is more critical than ever. In an effort to gain greater insight into this issue, Lozano et al., part of the Global Burden of Disease 2010 team, spent 5 years researching all available data related to mortality in 187 countries between 1980 and 2010. Their work was recently published in the Lancet (1). Lozano et al. present a complex and thorough analysis of the collected data with the aim of determining cause-specific mortality per age group, year, and country. A stepwise methodology was used to collect and analyze data. Sources included medical certification of causes of death, verbal autopsy data, population-based cancer registries, police and crime reports, demographic and health surveys, as well as data on deaths in health facilities. The data collection and study analysis consumed a daunting 5 years, with countless hours dedicated to imperfect data processing. The study period was over 30 years, but because data prior to 1990 were deemed insufficient for robust analysis, the final analysis was done for the years 1990e2010. Data were then processed using complex statistical models. For the modeling of individual causes of death, the Cause of Death ensemble Modeling was used for all major causes of death except HIV/AIDS and measles. For rare causes of death, the authors used fixed proportion models. Finally, the authors combined the results for individual causes of death to generate a final model. In their final analysis, the 2 leading causes of death worldwide between 1990 and 2010 remain ischemic heart disease and stroke. Ischemic heart disease was responsible for 13.3% among all causes of death in 2010; stroke followed at 11.1%, roughly split equally between ischemic stroke and hemorrhagic stroke. Combined, ischemic heart disease and all forms of stroke resulted in 12.9 million deaths in 2010, a quarter of the global total, compared with one fifth of the global total 20 years earlier. These numbers, however, should be cautiously interpreted in light of