Background: Gross total resection of pediatric posterior fossa tumors is paramount towards improving progression-free survival.

Fluorescein accumulates in tumoral tissue, where the blood-brain barrier is disrupted. It can therefore potentially aid in differentiating tumoral versus normal tissue. We aimed to evaluate the efficacy of fluorescent-guidance (using fluorescein) towards the resection of a pediatric cerebellar tumor, as the index case at our institution using this technique. Methods: 5 mg/kg of IV fluorescein sodium was injected upon induction of general anesthesia. During tumor resection, a yellow 560-nm filter (Kinevo microscope, Zeiss) was employed for fluorescent-guidance. The extent of resection was assessed via post-operative MRI. Results: There were no adverse side effects experienced by the patient. Tumoral material was clearly visualized under the yellow 560-nm filter, allowing for satisfactory gross total resection of the lesion (confirmed on post-operative MRI). Preliminary pathology was consistent with medulloblastoma. Conclusions: Fluorescent-guided resection of pediatric posterior fossa tumors appears to be a safe and useful adjunct for gross total resection of these lesions. To the best of our knowledge, this is the first reported case in Canada wherein IV fluorescein was used under a yellow 560-nm filter for resection of a posterior fossa medulloblastoma in a child.

Background: Postoperative follow-up of non-functioning pituitary adenomas (NFAs) occasionally detects residual or recurrent disease. Subsequent treatment options range from continued follow-up, to re-resection or radiotherapy. To better understand current practice patterns on this topic, we surveyed neurosurgeons and radiation oncologists in Canada. Methods: Skull-base neurosurgeons and radiation oncologists across Canada were invited to complete a 25-item online questionnaire. Summary statistics were computed and 2-tailed t-tests were performed to assess significance. Results: 33 participants returned completed questionnaires: neurosurgeons (n=20, 61%) and radiation oncologists (ROs; n=13, 39%). When treating giant (>3cm) tumours, 92% of neurosurgeons in practice for less than 15 years use an endoscopic approach, as compared to only 57% of neurosurgeons in practice for 15 years or more. Additionally, younger neurosurgeons have a greater tendency to advocate for stereotactic radiosurgery (SRS) or re-resection (54% and 38%, respectively), as compared to older surgeons who show a higher propensity (29%) to advocate for observation. The presence of cavernous sinus extension appears to encourage neurosurgeons (40%) to offer radiotherapy sooner, as compared to 62% of ROs. Conclusions: Our results identify both variations and commonalities in practice amongst Canadian neurosurgeons. Approaches deviate in the setting of residual tumors based on years of practice.

Background: It is well understood that gliomas require vast supply of energy to proliferate, invade and spread. We wished to identify novel biomarkers by comparing normal brain and plasma to high and low grade gliomas using newer techniques in laser ionization mass spectroscopy - precision metabolomics and lipidomics. Methods: Single center IRB approved tissue bank of “normal” brain and plasma (n=6) and IDH wild-type GBM tissue and plamsa (n=29), IDH mutant GBM tissue and plamsa (n=6), Low grade glioma (n=4) tissue and plamsa were analyzed for over 2000 endogenous metbolites and complex lipids. Unbiased clustering and Random Forest plots and pathway analysis were performed with appropriate statsitical analysis (significance p < 0.05). Results: IDH mutant GBM had higher levels of 2-HG, however, plasma 2-HG did not reflect IDH genotype. Changes in glucose and fatty acid utilization were observed in IDH WT and mutant gliomas compared to normal brain tissue. Lipidomics of plasma and tissue of normal and gliomas did not reveal a biomarker reaching statistical significance. Conclusions: We will continue to investigate if plasma and tissue biomarkers including hypotaurine, methionine, branched chain amino acid catabolites and pregnonolone can be used to predict tumor progression, response to treatment and clinical outcomes.

Background: The Novalis Certification Program is dedicated to providing a comprehensive and independent assessment of safety and quality in stereotactic radiosurgery (SRS). Methods: The program includes an independent review of SRS program structure, adequacy of personnel resources and training, appropriateness and use of technology, program quality management, patient-specific quality assurance and equipment quality control. Centres applying for Novalis Certification complete a self-study prior to a one-day visit by reviewers. Reviewers generate a descriptive 77-point report which is voted on by a multidisciplinary expert panel. Outcomes of reviews include mandatory requirements and optional recommendations, with the former requiring resolution prior to award of Certification. Sites undergo recertification every 4 years. Results: To date, 42 institutions have received Novalis Certification. A further 140 certification applications are pending. Two sites have been recertified, with 4 more in process this year. Analysis of review outcomes identified improved documentation of procedures as a frequent requirement, while frequent recommendations pertain to equipment/systems QA procedures and effective use of checklists/time outs. Conclusions: Novalis Certification is a unique, expanding peer review program assessing safety and quality in SRS and recognizing a high caliber of practice internationally. The standards-based approach highlights outstanding requirements and provides recommendations to enhance both new and established programs.

Background: Molecular signatures are being increasing used to classify central nervous system (CNS) tumors with incorporation into World Health Organization (WHO) classifications. A recently published genome-wide DNA methylation-based CNS tumor classifier assisted in diagnostically challenging cases. However its impact on patient care has not been reported, limiting translation to other centres. Methods: All 55 challenging CNS tumour diagnoses over three years underwent DNA methylation profiling. Tumor classification along with copy number variant (CNV) plot results were integrated with histopathological findings to determine final diagnoses and corresponding clinical impact was assessed. Results: After methylation profiling 46/55 (84%) received clinically relevant diagnostic changes, 30 (55%) with a new diagnosis or resolved differential diagnosis and 16 (29%) with clinically important molecular diagnostic or subtyping changes. WHO grade changed in 15 (27%), with two-thirds upgraded. Nine new IDH mutations in gliomas, four new molecular subtypes in medulloblastomas/ependymomas, and three false positive 1p/19q codeletions were identified. Patient care was directly changed by methylation profiling in 7/47 (15%) followed-up cases to avoid unnecessary treatment in three, insufficient treatment in three, and medically assisted death in one. Conclusions: This real-world use of methylation-based CNS tumor classification substantially impacts patient care for diagnostically challenging tumors and also avoids misdiagnosis-related uncessary resource use.

Background: Meningiomas are the most commonly occurring benign intracranial tumors. When presenting with peritumoral brain edema (PTBE), surgical treatment can lead to patient morbidity. This retrospective case series aims to describe the conservative medical management of moderate to large meningiomas with large PTBE. Methods: Patients with suspected meningiomas greater than 2.0cm and edema index greater than 2.0 were identified by screening 3345 MRI scans between 2012-2017. Imaging analysis included MR imaging features of suspected meningiomas and clinical data was gathered from the electronic patient record (patient age, sex, patient symptoms, follow-up duration, and follow-up symptoms). Results: We report on 31 patients who received conservative medical management. Presenting complaints included headache, seizure, weakness; many presented asymptomatically. The average follow-up time was 3.96 years. At the final follow-up appointment, 19 (61%) patients were asymptomatic. Among symptomatic patients, seizures were the most common complaint. There was no mortality reported in our cohort and the average tumor progression was 7.04cm3/year. Conclusions: In this retrospective report of meningioma patients with high edema index, we found that most patients remained asymptomatic or had stable symptoms after at least 1-yr follow up after medical treatment. This study provides insight around the surgical decision-making for meningiomas with large spread of edema.

Background: The Endoscopic endonasal approach (EEA) has been gaining popularity in the past decade as an alternative to traditional transcranial and transorbital approaches. We have performed orbital apex decompression for a variety of pathological entities. Methods: We performed a retrospective chart review on patients who underwent EEA orbital apex decompression between January 1st 2010 and December 1st 2018 at McMaster University. Results: Eight patients underwent endoscopic endonasal orbital decompression at our center, including five male patients and three female patients. The mean age of our patients was 50.1 years. The different pathologies we treated included nasopharyngeal carcinoma, hemangioma, fibrous dysplasia, IgG4 disease, inverted papilloma, angioleiomyoma, and neuroendocrine paraganglioma. Five patients presented with visual symptoms. Postoperatively, one of these five patients improved to baseline, three had stable vision, another one had progressive visual decline despite surgical intervention. Conclusions: Endoscopic endonasal approach can be used as an alternative to decompress orbital apex pathologies in selected patients.

Background: Pneumocystis jirovecii pneumonia (PJP) is an opportunistic interstitial fungal pneumonia. The incidence of PJP in HIV-positive populations is decreasing, while it is increasing in HIV-negative immunocompromised populations, such as neurosurgical patients treated with high-dose corticosteroids. Morbidity and mortality can be severe owing to acute respiratory failure. Methods: Two cases are described and a literature review performed to determine the incidence of PJP in the neurosurgery population. A standardized care pathway is proposed to reduce preventable harm. Results: Long-term, high-dose corticosteroid regimens (≥4 mg dexamethasone daily for ≥4 weeks) with taper are associated with increased risk of PJP infection. Additional risk factors for infection in HIV-negative patients include CNS malignancy and concurrent radiation therapy. TMP-SMX is the first-line agent for PJP prophylaxis. Conclusions: Clinicians should maintain a high index of suspicion of PJP and adopt a standardized protocol for prophylaxis in neurosurgical patients treated with high-dose corticosteroids.

Background: Previous studies have shown varied results with respect to the diagnostic utility of a positive nerve root sedimentation sign (SedSign) on MRI for symptomatic lumbar stenosis. The objective of this study was to analyze the clinical characteristics of SedSign utilizing a validated classification for low back and leg pain (Saskatchewan Spine Pathway classification; SSPc). Methods: This was a retrospective review of prospectively-collected data in 367 consecutive adult patients presenting to a spine surgeon with back and/or leg pain between January 1, 2012 and May 31, 2018. Inter- and intra-rater reliability for SedSign was 73% and 91%, respectively (3 examiners). Results: SedSign was positive in 111 (30.2%) and negative in 256 (69.8%) of patients. On the univariate analysis, a positive SedSign was correlated with age, male sex, several components of ODI, EQ5D mobility, cross-sectional area (CSA) of stenosis, and SSPc pattern 4 (intermitted leg dominant pain). On multivariate analysis, SedSign was associated with age, male sex, CSA stenosis and ODI sub-score for walking distance. The sensitivity and specificity of SedSign for neurogenic claudication was 50.3 and 82.9, respectively (positive predictive value 65.8%, negative predictive value 71.9%). Conclusions: The SedSign has high specificity for neurogenic claudication, but the sensitivity is poor.

Background: Due to increasingly limited access to cadavers and first-hand operative experience, there is an increasing need for innovative modalities in neurosurgical education. Recent developments in computer modelling, virtual/augmented reality, and video game technology have created new opportunities for novel teaching tools. We set out to develop a library of 3D models of normal anatomy and pathologic states for use in conjunction with an interactive simulated environment and 3D printing for teaching of neurosurgical residents. Methods: Anatomically accurate 3D models were developed using CT/MRI data from multiple patients using open source segmentation and 3D animation software. An interactive simulated environment was then created using a 3D game engine and used in conjunction with a virtual/augmented reality system. 3D models were also used to for 3D printing. Results: 3D models and an interactive simulated environment were used in conjunction with various viewing modalities, including 3D video, 360 video, and virtual reality headsets, as well as 3D printing. These teaching tools were successfully implemented in neurosurgery didactic teaching sessions and in the skull base lab. Additional benefits were seen with patient engagement and marketing. Conclusions: 3D modeling and animation show considerable promise for neurosurgical education, with additional benefits for patient engagement, marketing, and social media.

Background: In preparation for July 2019 rollout of competency-based design (CBD) in Canadian neurosurgery residency training, the University of Calgary launched a pilot-program of five representative EPAs using the One45 program. Our study objectives were to examine the uptake of CBD with residents and faculty and to quantify CBD implementation barriers. Methods: Phase one of the One45-based CBD pilot-program launched on November 1st, 2018 and ended on January 8th, 2019, after which a questionnaire was sent to each participating resident. The questionnaire examined number of EPAs initiated, measures of favourability, importance, ease of use, and barriers encountered. Results: Results obtained from the survey show 93.8% response rate (15/16 residents). 66.7% of residents feel that CBD is moderately important or higher to their education. Over the 10 study weeks, there were only 8 completed EPAs (expected was 50), five of which were completed by a single resident. Major expressed barriers of implementation of CBD were time involved (50.0%) and technical unfamiliarity with the platform itself (50.0%). Conclusions: This study demonstrates the critical importance of piloting a CBD program prior to official implementation as immediate buy-in was significantly slower than anticipated. Technical and time barriers exist which need to be rectified in advance of July 2019.

Background: People of aboriginal ancestry are more likely to suffer traumatic spinal cord injury (TSCI) compared to other Canadians; however, outcome studies are limited. This study aims to compare aboriginal and non-aboriginal populations with acute TSCI with respect to: pre-injury baseline, injury severity, treatment, outcomes, and length-of-stay characteristics. Methods: This was a retrospective analysis of 159 patients with TSCI prospectively enrolled in the prospective Rick Hansen Spinal Cord Injury Registry (RHSCIR), Saskatoon site between February 13, 2010 and December 17, 2016. Results: Sixty-two patients consented to the full dataset, which includes ethnic background: 21 ‘aboriginal’ (33.9%); 41 ‘non-aboriginal’ (66.1%). Aboriginal patients were younger, had fewer medical comorbidities and had similar severity of neurological injury and similar outcomes compared to non-aboriginal patients. However, the time to discharge to the community was significantly longer (median 104.0 days versus 38.5 days, p=0.021). While 35% of non-aboriginal patients were discharged home from the acute care site, no aboriginal patients were transferred home directly. Conclusions: This study suggests a need for better allocation of resources for transition to the community for First Nations patients with TSCI in Saskatchewan. We plan a further study to assess outcomes from TSCI for First Nations patients across Canada.

Background: Penetrating traumatic injuries to the clivus are rare. We describe the case of a 79-year-old man who presented to the emergency room with a butter knife protruding from his left cheek. Imaging showed the blade entering just beneath the left zygoma and transecting the clivus to terminate within the prepontine cistern. The tip of the knife abutted the right anterior inferior cerebellar artery and lower basilar artery. Methods: He was brought to the interventional neuroradiology OR with knife in place, by a combined surgical team of ENT, neurosurgery, and neuroradiology. Under local anaesthetic and intravenous sedation, vascular access to the distal left vertebral artery was obtained and a balloon positioned. Traction was applied to the knife and the knife was successfully removed avoiding any angular or rotational movements. An immediate angiogram showed no evidence of arterial injury. Results: The patient recovered uneventfully and was discharged home with no neurological deficit. Follow-up CT/CTA was performed a month later and confirmed no pseudoaneurysm or other complication. Conclusions: Management of penetrating skull base injuries by a multidisciplinary surgical team is advisable. Vascular imaging is crucial. Positioning of balloons within large vessels close to the penetrating object is recommended to control bleeding that may occur on removal.

Background: Pediatric craniocerebral gunshot wounds occur in the context of both accidental and intentional trauma. Unique physiologic factors merited research into prognostic factors and treatment priorities in the pediatric population. Methods: A systematic search of MEDLINE, EMBASE, Web of Science, LILACS, Cochrane Registered Trials and Systematic Reviews, ISRCTN, and ClinicalTrials.gov was conducted. Selection criteria included all studies published in any language since 2000 which described intracranial isolated gunshot wounds in a civilian individual or population of pediatric age. Post-mortem and epidemiological studies were excluded. Screening was conducted through Covidence. Results: Initial database search revealed 349 unique studies for abstract and title screening. Fifty studies were selected for full text screening. Nine studies were included in the final review. Study quality was assessed with the Newcastle-Ottawa Scale. Case series noted bullet migration, pituitary deficiency, neurovascular and neuropsychological concerns. Three single-center retrospective studies of 71, 30, and 48 pediatric patients suggested multiple negative prognostic signs on initial presentation. Early aggressive surgical treatment was recommended by some authors. Conclusions: This systematic review analyzed the best current understanding of evidence for prognostic factors and treatment considerations of intracranial gunshot wounds in the pediatric neurotrauma context. Areas for future research with larger multi-center studies were highlighted.

Background: Cellular prion protein (PrPC) is a lipid raft protein locallizing within CNS tissue. It is reguated by a disiintegrin and metaloproteinase domain containing protein 10 (ADAM10), which induces ectodomain shedding. PrPC has been previousy implicated as a ptentia lbiomarker for TBI, but no prior studies have examined the potential of ADAM10 as a biomarker. Methods: Serum samples from patients admitted for TBI were collected and patient data was recorded. Control serum was acquired from a commercial tissue bank. Patient GCS was recorded during admission. Serum was used for ELISA to assess PrPC and ADAM10 expression. GraphPad was used to conduct ANOVA and regressional analysis. Results: 37 control and 20 TBI samples were collected. Of the TBI patiients, 8 were mild, 3 were moderate, and 9 were severe cilnical grade. Both PrPC and ADAM10 were elevated in TBI patients compared with control (p<0.001). ADAM10 exhibited a dose response, with greter expression in patients with higher clinical grade. There was no significant association of either PrPC or ADAM10 with time after injury. Conclusions: Our results indicate that PrPC and ADAM10 may be useful tools for screening of TBI. ADAM10 is associated closely with clinlcal grade, and may in the future represent a promising prognostic tool.

Background: Micrographia is a rare neurological finding in isolation. Most cases of isolated micrographia have been found in association with focal ischemia of the left basal ganglia. Methods: We present a case of post-traumatic micrographia stemming from contusion to the left basal ganglia. We performed a detailed analysis of the patient’s writing at three-year follow-up. Results: A halthy 15 year old male was admitted following a BM accident. CT showed contusion to the left basall ganglia/external capsule. MRI was negative for underlying lesion. He had a short stay in the ICU and then was discharged. Two years later, he expressed concern regarding difficulty with sma, cramped writing at school. Writing analysis revealed micrographia with spontaneous printing as well as printing to dictation, but not with copied English nor Japanese writing. Conclusions: Isolated micrographia is a rare neurological finding. We present the incidence of this symptom folllowing gliding contusion to the et basal ganglia and external capsule.

Background: In aneurysms overall, a lower rate of recanalization in stent assisted coiling vs coiling alone has been observed without an increase in morbidity. This study aims to stratify and compare degree of occlusion outcome by treatment modalities. Secondarily, this study aims to stratify and compare postoperative adverse events. Methods: MEDLINE and EMBASE databases were searched. Study center were reviewed for inclusion. We performed meta-regressions, bias analysis and fail-safe N. We controlled for the quality of the studies. Results: 396 nonduplicated patients were separated into 4 groups: microsurgical, stent-assisted coiling, coiling, stent only. Stent-assisted coiling has lower rate of retreatment (17 vs 24%) and higher rehemorrhage (5% vs 3%) compared to coiling. Stent-assisted has higher rates of complete occlusion (55% vs 45%) and lower rate of residual aneurysm (15% vs 23%) compared to coiling. Comparative analyses were performed. Microsurgical remained the most morbid modality with the best rate of complete occlusion (93%) and lowest rehemorrhage (2%) and retreatment rate (5%). Conclusions: This is the first and largest meta-analysis focusing on patients treated for basilar apex aneurysm. To our knowledge, this is the first study to stratify and compare degree of occlusion per treatment modality. This study provides benchmark numbers to guide clinicians.

Background: Headaches are a major cause of disability and healthcare cost worldwide. When investigating headaches etiology, incidental unruptured intracranial aneurysms are often considered unrelated. We conducted a systematic review and meta-analysis to assess headaches outcomes (severity) after treatment of unruptured intracranial aneurysm. Methods: MEDLINE and EMBASE were systematically reviewed. Results: The data from eligible studies (n=7) was extracted and analyzed. 309 nonduplicated patients provided patient-level data for analysis. All studies used the 10-point numeric rating scale (NRS). 88% of patients were treated with endovascular technique. Overall, the observed effect estimate under a random effects model was found to be a standard mean difference in pre- and post-intervention headache severity of -0.448 (95% CI: -0.566 to -0.329). No significant heterogeneity was noted. No significant publication bias was demonstrated. Conclusions: This is the first and largest systematic review assessing postoperative headache outcomes after treatment of unruptured intracranial aneurysm. A significant reduction in headache intensity after treatment is observed in the current published literature. This study highlights an interesting clinical phenomenon that still warrants scientific effort before it can influence clinical practice. We encourage future study to stratify headache outcomes by aneurysm size, location and treatment modality.

Background: While recent clinical trials have demonstrated immense efficacy of mechanical thrombectomy (MT) in the setting of acute stroke, there remains debate over the safety in performing this procedure under general anesthesia (GA). In the Saskatchewan Acute Stroke Pathway, all patients presenting with LVO have endovascular thrombectomy performed under GA. Methods: Data was retrospectively reviewed on 108 consecutive LVO in 2016-2017. All MT were done under GA. Anatomical location of LVO, pre-MT ASPECTS score, post-MT TICI scores and 90-day NIHSS and mRS were recorded. Results: Of 108 LVO, 103 went on to have MT. 44 were right anterior circulation, 50 were left anterior circulation and 9 were posterior circulation. Of 94 anterior circulation strokes, 47 (50.0%), 43 (45.7%) and 4 (4.3%) had good, moderate and poor collateral circulation respectively, and the average pre-MT ASPECTS was 8.6. The average pre-MT NIHSS was 14.7. 81/90 (90.0%) achieved thrombolysis in cerebral infarction (TICI) perfusion scale grade of 2b/3 after recanalization. Average documented 90-day NIHSS was 2.4 and mRS was 2.5. Overall mortality was 21/103 (20.4%). Conclusions: In the Saskatchewan acute stroke pathway, general anesthesia is a safe modality for MT. This adds to the body of evidence supporting GA as a viable option for sedation in MT.

Background: Cerebral vasospasm is a leading cause of neurological disability following aneurysmal subarachnoid hemorrhage (aSAH). Clinical features associated with vasospasm development include blood burden on CT, neurological status, age and aneurysm location. Early cerebral CT perfusion (CTP) scanning in aSAH may be an independent predictor of vasospasm and/or delayed cerebral ischemia (DCI). Methods: Forty-one patients with aSAH were prospectively enrolled. Baseline data collected included WFNS grade, loss of consciousness at ictus, and modified Fisher grade. CTP was obtained at baseline and on day 6 post SAH. Cerebral blood volume, cerebral blood flow and mean transit time were measured. DCI was confirmed by a combination of clinical assessments, non-contrast CT and CTP. Radiological vasospasm was assessed with CT angiography. Results: Despite 80% of patients having a modified Fisher grade 3 or 4 aSAH, one-third presenting with ictal LOC and half having anterior communicating artery aneurysms, only one patient developed clinical evidence of vasospasm/DCI. Two others had asymptomatic radiological vasospasm. CTP parameters did not differ between groups defined by clinical predictors. Conclusions: In an unexpected finding, clinical and radiological vasospasm were very uncommon in this cohort. Clinical predictive variables correlated poorly with development of vasospasm. CTP may help refine the model but further work is needed.