Background: The Canadian Neurosurgery Research Collaborative (CNRC) is a trainee-led multi-centre collaboration made up of representatives from 12 of 14 neurosurgical centres with residency programs. To demonstrate the potential of this collaborative network, we gathered administrative operative data from each centre in order to provide a snapshot of the operative landscape in Canadian neurosurgery. Methods: Residents from each training program provided adult neurosurgical operative data for the 2014 calendar year, including the number of surgeries in the subcategories cranial, spinal, and peripheral nerve. Because some residency programs have surgeries distributed among more than one hospital, we calculated mean case load per residency program and per hospital. Results: Interim results from 6 neurosurgery residency programs are presented (with data from other programs forthcoming). Overall, there were on average 2,352 operative cases per residency program (n=6) and 1,176 operative cases per adult hospital (n=12). Among 5 programs with more detailed operative data, the mean numbers of cranial, spinal, peripheral nerve, and miscellaneous surgeries per residency program were 757 (47%), 487 (30%), 47 (3%), and 319 (20%) respectively. Conclusions: We show as a proof-of-concept that a trainee-led nation-wide research collaborative can generate meaningful data in a Canadian context.

Leptomeningeal metastasis is a serious complication of systemic cancer commonly occurring in later disease stages which affects approximately 10% of patients with solid tumors. The risk is highest for patients with lung cancer, melanoma and breast cancer. Survival at one year is in the range of 10%. Cerebrospinal fluid analysis and magnetic resonance imaging are the most important diagnostic measures. Treatment recommendations vary by primary tumor and pattern of disease, that is, e.g., the absence or presence of concurrent systemic or solid brain metastasis. To explore the current practice of diagnosing and treating leptomeningeal metastasis across Europe, a web-based survey was sent to members of the European Association of Neuro-Oncology (EANO) and the Brain Tumor Group of the European Organisation for Research and Treatment of Cancer (EORTC) in April 2016 which contains 24 questions on current practice patterns as well as 8 case presentations. The results of this survey will be presented for the first time. They shall serve as the basis for treatment recommendations for this complication of systemic cancer that reflects current knowledge as well as current practice.

Classical neurosurgical teaching suggests that corticosteroid administration reduces the diagnostic yield of stereotactic brain biopsy for primary central nervous system lymphoma (PCNSL). In a single-center series spanning 6 years, we reviewed 155 consecutive biopsy patients, 135 treated with prebiopsy corticosteroids. PCNSL was correctly diagnosed on initial biopsy in 15 of 16 steroid-treated patients; in the single nondiagnostic specimen, polymerase chain reaction reanalysis by an outside institution showed evidence of lymphoproliferative disease consistent with PCNSL. Our data challenge the notion that it is necessary to withhold corticosteroid therapy for cerebral edema in patients awaiting stereotactic biopsy for suspected PCNSL.

Background: This study examined mortality due to multiple sclerosis (MS) in Canada, 1975-2009 to determine whether there has been a change in age at death relative to the general population and decrease in MS mortality rates. Methods: Mortality rates/100,000 population for MS and all causes were calculated using data derived from Statistics Canada, age-standardized to the 2006 population. Results: The average annual Canadian MS mortality rate, 1975-2009 was 1.23/100,000. Five-year rates for 1975-79, 1980-84, 1985-89, 1990-94, 1995-99, 2000-04, 2005-09 were: 1.16, 0.94, 1.01, 1.16, 1.30, 1.43, 1.33. Trend analysis showed mortality rates over the entire 35 years were stable (average annual percent change of less than one percent). The average annual 1975-2009 rates for females and males were 1.45 and 0.99. Five-year female rates were always higher than males. Regardless of gender, there was a decrease in MS mortality rates in the 0-39 age group and increases in the 60-69, 70-79, and 80+ groups over time. In contrast, there were decreases in all-cause mortality rates across each age group. The highest MS mortality rates for 1975-2009 were consistently in the 50-59 and 60-69 groups for both genders, while the highest all-cause mortality rates were in the 80+ group. Conclusions: Changes in the age distribution of MS mortality rates indicate a shift to later age at death, possibly due to improved health care. However MS patients remain disadvantaged relative to the general population and changes in age at death are not reflected in decreased mortality rates.

Human rabies encephalitis is rare in Canada, with only five cases reported in the past 30 years. The first and only patient who contracted rabies encephalitis in British Columbia died in 2003. Here we provide the first detailed clinical and pathological description of that case, which had several unusual features, including preexisting immunosuppression, paralytic presentation, prolonged survival, focal lesions on neuroimaging and severe neuropathology with focal necrosis, intense inflammation, and abundant viral inclusion bodies.

Intracranial metastases from solid tumors are increasingly common, often brain or leptomeningeal metastases. Dural metastases are under-reported, present diagnostic and therapeutic challenges, and may mimic subdural hematoma or meningioma. This report describes 4 recent patients with dural metastases from breast cancer. A 60 year old woman, without known cancer, had 5 months of increasing headaches, left weakness, and focal seizures. Imaging showed an enlarging right frontal extra-axial enhancing mass with edema, initially thought to be a meningioma. At surgery the tumor involved overlying bone, replaced the dura, and invaded brain. Pathology was metastatic adenocarcinoma, ER/PR positive and Her-2 negative. Investigations showed a right breast primary, and lung and bone metastases. She received cranial radiotherapy (RT), letrozole and pamidronate. The tumor remains controlled after 40 months. The 3 other patients all had prior known breast cancer, 2 ER/PR positive and Her-2 negative, and 1 triple negative, ages 45-70 years. Two had known systemic metastases prior to neurological presentation. Presenting symptoms included headache, seizures, focal weakness, and confusion. All had new or progressive systemic metastases, including bone, at diagnosis of dural metastases. Two had resection of dural metastases, 1 with complicated postoperative course, with eventual improvement in both. Two received cranial RT, 1 refused RT, and all received hormonal or chemotherapy, with ongoing clinical or MRI control. These cases illustrate the complexity of dural metastases. Although patients often have extensive metastatic disease, treatment can improve symptoms and prolong survival.

Background: Aggressive surgical resections of posterior fossa tumours result in tremendous neurological sequelae as a result of damage to the brainstem. As such we sought to re-evaluate the role of aggressive surgical resections in the molecular era. Methods: 820 posterior fossa ependymoma and 787 medulloblastoma were genomically profiled and correlated with pertinent clinical variables. Results: Across 787 medulloblastoma cases, the value of extent of resection was greatly dampened when accounting for molecular subgroup. Near-total resections are equivalent to gross total resections across all four subgroups even when correcting for treatment. The prognostic value of a gross total resection as compared to a subtotal resection (>1.5cm2 residual) was restricted to Group 4 tumours (HR 1.26). Across 820 posterior fossa ependymoma PFA ependymoma was a very high risk group compared to PFB ependymoma, and a subtotal PFA ependymoma conferred an extremely poor prognosis. Gross totally resected PFB ependymoma could be cured with surgery alone. Prognostic nomograms in both medulloblastoma and ependymoma revealed molecular subgroup to be the most important predictor of outcome. Conclusions: The prognostic benefit of EOR for patients with medulloblastoma is marginal after accounting for molecular subgroup affiliation. In both molecular subgroups of posterior fossa ependymoma, gross total resection remains an important predictor of outcome.

Background: Quality control indicators for mass lesion in TBI use the delay between emergency department (ED) and OR arrival to measure quality of care. It does not provide the timing of brain decompression. The goals of this study are to observe step by step where delays occur from hospital admission until effective decompression of the brain. Methods: A prospective observational data collection of timing from ED admission to decompression was conducted for all emergency trauma craniotomies over a period of 15 months. Results: Sixty-five patients were included. Doing a CT at the outside institution instead of transferring the patient prior to CT resulted in a 112min delay in care. Neurosurgery team notification prior to patient’s arrival to ED shortened delivery of care by 51min. The time elapsed between OR arrival and brain decompression was 50min: anesthesia time 3min, surgical positioning/preparation 29min and surgical time 17min. Burrhole decompression followed by craniotomy (9min) shortened the decompression time by 17min compared to standard 4 holes craniotomy approach (26min). Conclusions: Benchmark for trauma system performance in emergency craniotomies should be door to decompression time. Bypassing CT in local hospitals, pre-alerting neurosurgeons, and burrhole decompression followed by standard craniotomy significantly decrease door to decompression time.

Background: Multiple sclerosis (MS) is a lifelong neurological disorder requiring care in a variety of settings. The purpose of this study is to describe preferences of general practitioners (GPs) with regards to providing care for MS patients.Methods: A stratified sample of 900 GPs in the province of Quebec were sent a questionnaire, with 266 returning completed questionnaires. Respondents were surveyed about their preferences using four clinical scenarios describing hypothetical patients experiencing different stages of MS. Respondents were asked whether they would continue managing the patient themselves, formally refer the patient to a specialist, or seek specialist advice.Results: In two scenarios representing stable courses, 40.9% and 61.6% of GPs, respectively, intended to manage the patient themselves. GPs who reported having experience with MS patients were more likely to report an intention to continue management. In one scenario, GPs operating in rural areas were less likely to consider management than those in the Montreal metropolitan area (odds ratio=0.422, 95% confidence interval 0.20-0.90). Conclusions: For MS patients with a stable disease course, an important proportion of GPs appear to be willing to manage long-term care for MS patients.

Predictive modeling of dose fall-off in radiosurgery could assist in clinical decision-making when prescribing a treatment plan with minimized toxicity risk. The purpose of this study is to develop a predictive dose fall-off model. Materials/Methods: We retrospectively reviewed treatment plans from 257 patients (365 lesions) with total doses ranging from 20 to 35Gy in 5 fractions. For each plan, we measured both total volume of the external contour (EXT) and BrainMinusPTV (BMP) receiving P=20% to P=80% of the prescription dose. The model has form y=Fa(PTV)b+/-delta. y=volume of EXT or BMP (cc’s); a and b are curve-fitting coefficients; PTV=total planning target volume (cc’s); F is an adjustment factor (>1) to account for number of targets; delta is the 95% prediction band. F, a, b, and delta were modeled such that dose-fall can be forecast for any PTV and dose level. Results: The model coefficients were as follows: Coefficient EXT BMP a 19927(100×P)exp(-2) 17122(100×P)exp(-2) b 0.42(100×P)exp(0.17) 0.63 F -0.0156×(100×P)+2.5517 delta 384467×(100×P)exp(-2.3159) The table can be used to determine the model for any P from 20% to 80%. Example: the EXT receiving 50%, P=0.5, a=8.0, b=0.82, F=1.8, delta=45. Thus, EXT-50=8(PTV0.82) or 1.8×8(PTV0.82) for 1-3 or >3 targets, respectively,+/-45cc’s. The model was verified against published values of dose fall-off from linacs. Conclusion: A predictive dose fall-off model was generated for linac-based radiosurgery. The model can be used for quality assurance or for inter-institutional comparisons. Ongoing work is being conducted to extend the model to a SRS cones system.