Background: Decisions to treat large-vessel occlusion with endovascular therapy(EVT) or intravenous alteplase depend on how physicians weigh benefits against risks when considering patients’ pre-stroke comorbidities. Methods: In an international survey, experts chose treatment approaches under current resources and under assumed ideal conditions for 10 of 22 randomly assigned case-scenarios. Five included comorbidities(metastatic/non-metastatic cancer, cardiac/respiratory/renal disease, non-disabling/mild cognitive impairment[MCI], physical dependence). We examined scenario/respondent characteristics associated with EVT/alteplase decisions using multivariable logistic regressions. Results: Among 607 physicians(38 countries), EVT was favoured in 1,097/1,379(79.6%) responses for comorbidity-related scenarios under current resources versus 1,510/1,657(91.1%,OR:0.38, 95%CI.0.31-0.47) for six “level-1A” scenarios (assuming ideal conditions:82.7% vs 95.1%,OR:0.25,0.19-0.33). However, this was reversed on including all other scenarios(e.g. under current resources:3,489/4,691[74.4%], OR:1.34,1.17-1.54). Responses favouring alteplase for comorbidity-related(e.g.75.0% under current resources) scenarios were comparable to level-1A scenarios(72.2%) and higher than all others(60.4%). No comorbidity-related factor independently diminished EVT-odds. MCI and dependence carried higher alteplase-odds; cancer and cardiac/respiratory/renal disease had lower odds. Relevant respondent characteristics included performing more EVT cases/year (higher EVT, lower alteplase-odds), practicing in East-Asia (higher EVT-odds), and in interventional neuroradiology(lower alteplase-odds vs neurology). Conclusions: Moderate-to-severe comorbidities did not consistently deter experts from EVT, suggesting equipoise about withholding EVT based on comorbidities. However, alteplase was often foregone when respondents chose EVT.

Background: Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, aneurysms, and vessel sacrifice, but can be limited by currently available embolization agents. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to develop and test a novel embolization agent using hydrogels, a class of materials which may be bioengineered to suit a variety of indications. Methods: We devised a method of liquid hydrogel embolization with photo-modulated crosslinking for intravascular solidification, using a custom microcatheter set-up. We tested this in swine blood vessels (n=3), the swine renal arterial trees as a vascular tumor model (n=5), and the swine arterial-arterial networks of the rete mirabile as an AVM model (n=3). Hydrogel embolization was assessed for treatment efficacy and safety. Follow-up angiography was performed at 2-4 week intervals. Results: Hydrogel embolization was technically successful in all animals, with full occlusion of the vascular target immediately following embolization and at follow-up. There were no instances of clinical or angiographic complications. Conclusions: We demonstrated a novel method of dynamic photomodulation and delivery of bioengineered hydrogels to address current limitations of endovascular embolization therapies. This promising technology will be investigated further with longer-term comparative animal trials.

Background: Arterial Hemodynamics have been implicated in hemorrhage from cerebral arteriovenous malformations (AVMs). The correlation between hemodynamic characteristics and the tendency of AVMs to rupture has been explored in the past, and various theories have been proposed to explain the clinical presentation of AVMs as a hemorrhage vs. seizure. Methods: We monitored feeder artery pressures in 45 patients with AVMS (16 presenting with hemorrhage, 29 without) during super selective angiography and AVM embolization. Results: Mean feeder artery pressure (FP) was found to be 49mm Hg. The mean FP in patients presenting with hemorrhage was somewhat higher than in those without hemorrhage, but the difference was not statistically significant (53.8 mm Hg vs 47.0 mm Hg, p=0.13). Systemic mean pressure was found to correlate with AVM size (r=-0.31, p=0.037). Significant predictors of feeder artery pressure were systemic pressure, AVM size, and the distance of microcatheter from the circle of Willis. Meanwhile, the presence or absence of venous outflow stenosis and the position of the AVM nidus (superficial or deep to the cortical surface) were the most significant predictors of AVM hemorrhage vs seizures. Conclusions: Anatomic factors may be more important than arterial hemodynamic factors in determining the clinical presentation of cerebral AVMs.

Background: Competitive flow diversion (CFD) is a novel application of flow diversion stenting (FDS), redirecting flow into a normal artery proximal or distal to the aneurysmal parent artery. A classification system for CFD has not been previously reported. Methods: Report of operative technique and novel classification system for CFD. Results: A patient with subarachnoid haemorrhage and three aneurysms arising from the Pcomm-P1 complex, was treated with endovascular coiling and CFD. The PCOM aneurysm was coiled. Two aneurysms arose from the distal right P1- PCA. After a failed attempt to treat with FDS across the P1-PCA, the P1-aneurysms were successfully treated with CFD distal to the P1-PCA, from Pcomm to P2. Over 12 months, CFD redirected flow via ICA-Pcomm-P2, reducing the size of the P1-PCA, obliterating the P1-aneurysms. Herein, we classify competitive flow diversion into two types. Type I CFD is when the parent artery harbouring the aneurysm is “jailed” proximally. Type II CFD occurs when flow is diverted from the parent artery distal to the aneurysm origin. Conclusions: Herein, we propose a novel classification for CFD. We describe the first case of aneurysm occlusion in the circle of Willis with Type II CFD, and use of CFD for the treatment of multiple adjacent aneurysms.

Background: The promise of neuroprotection for stroke remains elusive. Common medications in endovascular stroke thrombectomy have putative neuroprotective mechanisms in basic science literature. We evaluated our stroke registry for evidence that these medications have any impact on clinically meaningful outcome. Methods: A retrospective stroke thrombectomy database was evaluated for clinical and angiographic outcomes of patients receiving IV or IA tPA, Heparin, or Verapamil during procedure. Univariate analysis evaluated associations with periprocedure hemorrhage, recanalization, and functional outcomes. Results: 284 patients underwent mechanical thrombectomy over 2.75 years. For periprocedural hemorrhage, IV tPA (OR 0.457, CI 0.261-0.811, p=0.008) and Heparin (1.897, CI 1.112-3.205, p=0.019) had significant relationships. No medication had impact on favorable recanalization (TICI 2b/3). Heparin had a negative impact on 90day mRS 0-2 (OR 0.563, CI 0.348-0.901, p=0.023). Favorable recanalization remains associated with favorable outcomes at 90days (OR 2.066, CI 1.063-4.069, p=0.0361). Conclusions: While the adjunctive use of 3 commonly used periprocedural medications have a logical role in the mechanical thrombectomy eg IA tPA for clot lysis, they do not have clinical benefit that represents neuroprotection. Multivariate analysis may show more effect. A role for intraarterial neuroprotective agents exists given only 45% of patients in this series achieved functional independence.

Background: A 3-year-old girl presented with a 6-day history of severe headaches. On examination, upper motor neuron signs were noted in the left upper and lower extremities with increased tone, reflexes, and a positive Babinski sign. MRI of the brain revealed a giant right middle cerebral artery (MCA) aneurysm with significant mass effect, associated with cerebral edema and ventricular effacement. CT and CT angiogram showed evidence of aneurysmal wall calcification and lamellar thrombosis within the aneurysmal sac. In addition, there was a smaller right MCA aneurysm in close proximity to the giant aneurysm. Methods: After a balloon occlusion test to assess collateral blood flow to the MCA territory, it was decided to treat both aneurysms with a flow diverting stent. Dual antiplatelet loading was done with aspirin and clopidogrel. The smallest available diameter of Pipeline Shield stent was deployed. Results: The patient remained neurologically unchanged. Early follow-up imaging demonstrated stent patency, reduced size and mass effect of the large aneurysm, reduced cerebral edema, and no flow into the smaller aneurysm. Conclusions: Flow diversion stenting may be employed successfully in pediatric patients, though has unique technical considerations including small size vessels and limited evidence for antiplatelet agent choice and dosing.

Background: Ischemic stroke occurs following trauma-related blunt cerebrovascular injury (BCVI) in up to 20% of cases. Preventative treatment includes antiplatelets, anticoagulants, and/or endovascular treatment (ET), but the optimal choice remains unclear. The objective of this study was to compare the ischemic stroke rate between these three treatments. Methods: Following PRISMA guidelines, we queried the OVID Medline, Embase, Web of Science, and Cochrane Library databases from September 2019 to inception to identify studies reporting treatment-stratified outcomes in BCVI patients. Meta-analysis was performed to compare outcomes between the treatment groups, using odds ratios. Retrospective review of our institutional experience with BCVI outcomes was performed and added to the meta-analysis. Results: Analysis of seven comparative studies of antiplatelets (n=334) versus anticoagulation (n=325) found no significant difference in ischemic stroke rate (OR 1.27, 95%CI 0.40-3.99), but a decrease in hemorrhagic complications (OR 0.38, 95%CI 0.15-1.00). Analysis of seven comparative studies of antiplatelets/anticoagulants (n=805) versus ET (n=235) also found no significant difference in stroke rate (OR 0.71, 95%CI 0.35-1.42). Conclusions: Antiplatelets and anticoagulants were similarly effective in reducing ischemic stroke risk in BCVI, but antiplatelets were better tolerated in this trauma population. The addition of endovascular treatment did not further reduce stroke risk compared to antiplatelets or anticoagulants alone.

Background: Transcranial Doppler (TCD) measurements poorly predict vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). Variability descriptors of mean cerebral blood flow velocity (mean-CBFV) may improve this prediction. We assessed the feasibility of generating reliable mean-CBFV variability metrics using extended TCD recordings in aSAH patients and healthy controls. We also explored whether these parameters are capable to discriminate aSAH patients from healthy controls, and between patients with and without vasospasm. Methods: Bilateral mean-CBFV, systemic blood pressure and heart rate were recorded for 40 minutes in 3 groups: aSAH patients (n=8) within the first 5 days post-ictus, age-matched healthy controls (n=8) and young healthy controls (n=8). We obtained linear [standard deviations, coefficient of variations, very-low, low and high-frequency power-spectra] and non-linear [Fractality, deterministic Chaos analyses] variability metrics. Results: All TCD recordings provided consistent variability metrics. aSAH patients showed higher correlation dimensions, increased high-frequency spectral power, and decreased very-low frequency power than healthy controls. aSAH patients who developed vasospasm (n=3) showed higher mean-CBFV and lower coefficient of variations than those without vasospasm (n=5). Conclusions: Descriptors of mean-CBFV variability may distinguish between aSAH patients with and without vasospasm. Future studies are required to evaluate the role of these variability parameters for risk stratification in aSAH.

Background: The frontal aslant tract (FAT) is a recently discovered white-matter tract connecting the medial superior frontal gyrus to the inferior frontal gyrus. There is increasing evidence for its importance in speech initiation and production. Despite this, there remains limited evidence demonstrating clinical outcomes when lesioning this tract. Methods: Medical records for the case were reviewed. Imaging was exported and tractography was performed using 3D Slicer. Results: A 58-year-old female presented with a focal seizure and imaging demonstrating a left frontal extra-axial lesion. She underwent a left frontal craniotomy for tumour debulking and biopsy. The final pathology was consistent with a diffuse large B-cell lymphoma. Postoperatively, she presented with expressive aphasia without agraphia. She was able to write out answers to questions she could not verbalize. We used tractography to provide evidence of postoperative disruption to her left FAT. At a 6-week clinical follow-up, her language deficits were clinically resolved. Conclusions: To our knowledge, this is the first reported case of aphasia without agraphia seen with disruption of the left FAT. Further elucidating clinical outcomes of disrupting the dominant FAT will aid in improved patient counselling, prognostication and neurosurgical planning. Further research is required to investigate the mechanisms underlying language recovery and handwriting.

Background: The use of Image-guidance to improve the accuracy during ventricular drain insertion has been attempted. We aim to assess the effect of use of Image-guidance on accuracy, drain failure rate and number of ventricular cannulation attempts. Methods: MEDLINE, EMBASE and Cochrane Library databases were searched from inception to February 2021 looking for studies comparing image-guided versus freehand ventricular drain insertion. Two reviewers independently screened studies, extracted data and assessed risk of bias and quality of evidence. Metanalysis was conducted in compliance with PRISMA guidelines using a random-effects model and GRADE tool was used to assess quality of evidence. Results: 17 studies with 3404 patients were included, all of which were of non-randomized design. Pooled data on drain accuracy and drain failure rates showed favourable effect of image-guidance with risk ratio of 1.31 (95% CI of 1.13 – 1.51, low quality evidence) and 0.63 (95% CI 0.48 – 0.83, moderate quality evidence), respectively. Pooled data were equivocal for number of attempts with mean difference score of -0.11 times (95% CI -0.31 – 0.09, very low-quality evidence). Conclusions: Image-guidance likely enhances drain accuracy and reduces drain failure rate. No clear recommendation can be drawn on the benefit of intervention on number of drain insertion attempts.

Background: Odontoidectomy for basilar invagination and craniovertebral junction pathology has traditionally been performed using a transoral route. However, the endoscopic endonasal approach to the anterior craniovertebral junction may offer safer and more effective access when compared to transoral approaches. Methods: This study is a retrospective chart review of all adult patients who underwent an endoscopic endonasal odontoidectomy at a single tertiary care center between January 2011 and May 2019. Results: Seventeen patients were included in the study. The median admission age was 67 years (range: 33-84 years) and 65% of the patients were female. One patient (1/17, 6%) had vertebral artery injury which was coiled with no neurological deficits, and 4 patients (4/17, 24%) had intraoperative CSF leaks with no postoperative leak. Fourteen patients (14/17, 82%) were extubated by POD 1. Three patients (3/17, 18%) developed postoperative sinus infections and required antibiotics. Eight patients (8/17, 47%) developed transient postoperative dysphagia. One patient (1/17, 6%) had postoperative epistaxis and one patient (1/17, 6%) had postoperative lower cranial nerve symptoms. The median length of hospital stay was 13 days (range: 2-44 days). Conclusions: Endoscopic endonasal odontoidectomy is a feasible and well-tolerated procedure for anterior decompression of craniovertebral junction, associated with satisfactory patient outcomes and low morbidity.

Background: Pituitary adenomas are common and often require complex multidisciplinary care with multiple specialists. This may result in a health care system that is challenging for patients to navigate. Audits of care at our institution revealed opportunities for improvement to better align care with patients’ needs. Methods: A quality improvement initiative that incorporated a patient advisory committee of patients who had received treatment for pituitary adenoma at our center and their family members was used to help identify opportunities for improvement. The patient-identified gaps in care included the need to coordinate and minimize appointments and the desire for better communication and education. Based on this information, changes were implemented to the pituitary program, including increasing access to the multidisciplinary clinic and developing a standardized and centralized triage process. Results: A pre and post-intervention analysis consisting of retrospective chart reviews revealed that these changes had an impact on wait times for first assessment, and a significant shift in location of this first visit – with a larger proportion of patients being seen in the multidisciplinary clinic after intervention. Conclusions: We demonstrate that patient involvement, beyond individual patient-physician interactions, can lead to meaningful and observable changes, and can improve the quality of care for pituitary adenoma.

Background: Hirayama Disease (HD) is a rare disorder consisting of insidious onset of unilateral weakness and atrophy of the forearm and intrinsic hand muscles. Vein of Galen aneurysmal malformations (VGAMs) are rare congenital cerebral vascular malformations, consisting of high-flow arteriovenous shunting between a persistent median prosencephalic vein and arterial feeders. Methods: 14 years old boy known for VGAM presented with left-sided HD. His cervical MRI revealed enlarged epidural with anterior, left-ward displacement of the posterior dura and spinal cord. He underwent surgical treatment by laminotomies, along with tenting of an autologous duroplasty to the overlying laminae. Results: We decided to combine epidural venous plexus coagulation with posterior duraplasty and dural fixation using tenting suture which led to a favorable clinical outcome has not been previously proposed in the literature.

We hypothesize that in this context, an abnormal vasculature could also predispose to posterior epidural venous plexus engorgement, anterior dural displacement in cervical flexion, and microvascular changes in the anterior spinal arterial circulation, leading to the progressive anterior horn cell ischemia that lead to the clinical phenotype of HD. Conclusions: The association between HD and VGAM in this patient may provide clues with regard to the pathophysiology of HD.

Background: Current literature provides little consensus on universal guidelines for first-line treatment of chronic subdural hematomas (cSDH). However, administration of local tissue plasminogen activator (tPA) may enhance the traditional method of twist drill drainage (TDD). The study aims to explore the efficacy of TDD with and without tPA, at achieving clinically relevant drainage (200mL) and reducing recurrence of cSDH. Methods: A retrospective review of patients (N=34) with cSDH is presented. Patients who received TDD with tPA (n=17) were identified and matched, based primarily on age and hematoma volume, to a control group (n=17), TDD without tPA. Variables of interest include initial hematoma volume, volume drained, length of stay, and recurrence rates. Descriptive analysis was run. Results: Average age for patients was 74.6 with 76% male. Mean drainage volumes for the tPA cohort was 381.6mL and TDD without tPA cohort was 151.3mL. The addition of tPA resulted in drainage volumes nearly double (1.9x) the clinically relevant amount and had low recurrence rates (12.5%). TDD without tPA failed to result in clinically relevant drainage and had a recurrence rate of 52.9%. Average length of stay differed by two days (9.71 tPA; 7.71 control). Conclusions: TDD with tPA was effective at treating cSDH in our population.

Background: Ventriculoperitoneal (VP) shunt failures in adult patients are common and subject patients to multiple surgeries and a decreased quality of life. A prospective cohort Shunt Outcomes Quality Improvement (ShOut-QI) initiative was implemented to reduce shunt failure incidence through neuronavigation-assisted proximal catheter insertion and laparoscopy-guided distal catheter anchoring over the liver dome to drain CSF away from the omentum. Methods: “Pre-ShOut” and “Post-ShOut” groups of patients included those with and without neuronavigation/laparoscopy, respectively for insertion of a new VP shunt. The primary outcome was shunt failure which was defined as any return to surgery for shunt revision as determined with a standardized clinical and radiology follow-up protocol. Results: 244 patients (97 Pre-ShOut, 147 Post-ShOut), mean age 73 years, were enrolled over a 7-year interval and observed for a mean duration of 4 years after shunt insertion. Neuronavigation improved proximal catheter placement accuracy by 20% (p<.001), and shunt failure occurred in 57% vs 23% in the Pre-ShOut and Post-ShOut groups, respectively (p=.008), representing a 53% relative risk reduction in the incidence of shunt failure. Conclusions: Adult shunt failure incidence may be significantly reduced by improving the accuracy of proximal catheter placement with neuronavigation and reducing the risk of distal catheter failure with laparoscopic-guided placement.

Background: To describe preliminary results of a multi-center, randomized, blinded, placebo-controlled, pilot trial of shunt surgery in idiopathic normal pressure hydrocephalus (iNPH). Methods: Five sites of the Adult Hydrocephalus Clinical Research Network (AHCRN) randomized 18 patients scheduled for ventriculoperitoneal shunting based on CSF-drainage response. Patients were randomized to a Codman® Certas® Plus valve with SiphonGuard at either setting 4 (Active, N=9) or setting 8/”virtual off” (Placebo, N=9). Patients and assessors were blinded to the shunt setting. Outcomes included 10-meter gait velocity, cognitive function, and bladder activity scores. The prespecified primary analysis compared changes in 4-month gait velocity in the Active versus Placebo groups. Placebo-set shunts were then blindly adjusted to the active setting and all patients underwent 8 and 12-month post-surgical assessment. Results: At 4-months, gait velocity increased by 0.28±0.28m/s in the Active Group and 0.04±0.17m/s in the Placebo Group (p=0.071). Overactive Bladder (OAB-q) scores significantly improved in the Active versus Placebo groups (p=0.007). At 8 months, Placebo gait velocity increased by 0.36±0.27m/s and was comparable to the Active Group (0.40±0.20m/s; p=0.56). Conclusions: This AHCRN study shows a trend suggesting gait velocity improves more at an Active shunt setting than a Placebo shunt setting and demonstrates the feasibility of a placebo-controlled trial in iNPH.

Background: Cranial reconstruction is a common consequence of neurosurgical disease and intervention following craniectomy, trauma, infection, congenital defects, or neoplasm. Most commonly, Computer Aided Design-Computer Aided Manufacturing (CAD-CAM) technology is utilized in cases where autologous bone cannot be used. These patient-specific implants provide excellent cosmesis, however individual costs range from $800-15,000, making routine use challenging in the current Canadian health care environment. Here we present a novel method using desktop 3D printers to manufacture patient-specific molds for intraoperative reconstruction of various cranial defects. Methods: Our first patient presented following two separate traumas requiring decompressive craniectomy and subsequent posterior fossa decompression without interval cranioplasty. The second patient required reconstruction during resection of intraosseous meningioma. Both cases were performed using a titanium-mesh/poly-methyl-methacrylate (Ti-PMMA) construct draped over the mold. The third case, cranioplasty following decompressive craniectomy outside the country, was performed using a “two piece” mold and PMMA was casted into the mold and allowed to harden. Results: Patients reported satisfaction with cosmesis, without adverse outcomes. Cost per case was $50-100, representing an estimated cost savings of $685,000 per year in Canada. Conclusions: Given excellent outcomes in addition to cost effectiveness, this case series provides evidence for use of this alternate technique with similar patient outcomes.

Background: Hydrocephalus is a common pediatric neurosurgical condition that requires lifelong care into adulthood. Significant gaps in care are thought to exist for youth transitioning to adult care, but little is known about how patients and their caregivers feel about the process. This study examines the perceptions of adolescents, young adults and caregivers when transitioning from pediatric to adult care at a single Canadian center. Methods: 40 patient/caregivers (7 adolescents, 13 young adults and 20 parents) treated at BC Children’s Hospital participated in semi-structured interviews using the qualitative research methodologies of grounded theory. Interviews were transcribed verbatim and coded, with common themes identified. Results: Four overarching themes relating to the process of transitioning from pediatric to adult care were identified: (1): Inadequacy of communication between pediatric and adult care teams and patients/caregivers; (2) Uncertainty relating to the prospect of life as an adult with hydrocephalus; (3) Anxiety and fear regarding navigating a new health care environment; and (4) sadness at the loss relationships with the pediatric health care team. Conclusions: We identified a general dissatisfaction with the transitioning process for hydrocephalus. Common themes and concerns identified may form the basis of an improved transitioning model for youth with hydrocephalus as they become adults.

Background: Tubular retractors are FDA approved and in the Neurosurgical marketplace, but adaptation has been hampered by lack of evidence showing superiority over traditional retractors when performing subcortical surgery. This study examines brain injury associated with traditional brain retractors versus tubular retractors. Methods: Nine porcine models underwent a simulated neurosurgical operation. Retractors were inserted for four hours after which the porcine model was euthanized. The en-bloc extracted porcine brain was fixed in 10% formalin, paraffin embedded, sectioned at 4 um and stained with hematoxylin and eosin (H&E) using standard laboratory protocols. Computer algorithms were generated to calculate areas of cerebral edema and hemorrhage adjacent to retractor surfaces. Results: Using a two-tailed t-test with a significance level of 0.05, traditional brain retractors were associated with statistically significant greater areas of cerebral edema when compared to tubular retractors (17.36 um2 vs. 12.42 um2; p = 0.0038). There was no statistically significant difference in mean areas of hemorrhage between traditional brain retractors and tubular retractors (3.43 um2 vs 3.60 um2; p = 0.8297). Conclusions: Tubular retractors are associated with significantly less edema in surrounding brain than traditional retractors. On histopathological merits, this study supports the application of tubular retractors over traditional retractors.

Background: Exploring current trends in career outcomes can guide further expansion and diversity in neurosurgery demographics, as well as inform medical trainees of qualifications required for a career in neurosurgery. This study therefore aims to explore temporal trends and gender distribution in training, teaching, and leadership positions among currently practicing neurosurgeons. Methods: A list of practicing Canadian neurosurgeons and their certification year, degrees, fellowships, and teaching positions was created using publicly available information and phone/email confirmation by surgeons. Results: We identified 297 neurosurgeons currently practicing in Canada (F=32, M=265). There was a significant trend towards a greater number of neurosurgical staff having at least one advanced degree or fellowship over time (p=0.0012, p=0.0048 respectively), with no significant difference between proportions of males and females. Within academia, women represent 33% of adjunct professors, 8% of associate professors, and 15.2% of full professors. Two neurosurgical departments in Canada are led by women. Conclusions: Literature shows there is an underrepresentation of women in neurosurgery, particularly in higher-ranking teaching and leadership positions, yet our results suggest there is no significant differences in qualifications between males and females. Further exploration is needed to identify reasons underlying these trends and propose solutions to promote growth in the field.