Background: The fragility index (FI) is the minimum number of patients whose status would have to change from a nonevent to an event to turn a statistically significant result to a non-significant result. We used this to measure the robustness of trials comparing carotid endarterectomy (CEA) to carotid artery stenting (CAS). Methods: A search was conducted in MEDLINE, Embase, and PubMed on RCTs comparing CEA to CAS. The trials need to have statistically significant results and dichotomous primary endpoints to be included. Results: Our literature search identified 10 RCTs which included 9382 patients (4734 CEA, 4648 CAS). The primary end points of all included trials favoured CEA over CAS. The median FI was 9.5 (interquartile range 2.25 - 21.25). All of the studies that reported lost-to-follow-up (LTFU) had LTFU greater than its fragility index, which raises concern that the missing data could change the results of the trial from statistically significant to statistically insignificant. Conclusions: A small number of events (FI, median 9.5) were required to render the results of carotid artery stenosis RCTs comparing CEA to CAS statistically insignificant. All of the studies that reported LTFU had LTFU greater than its fragility index.

Background: Pediatric arteriovenous malformations (AVMs) are rare, but represent the leading cause of intracranial hemorrhage in children. These are traditionally understood to be congenital lesions, however AVMs recurrence within previously unaffected tissue challenges this understanding. Recurrence after microsurgery and endovascular treatment have been studied in greater detail, but little literature exists surrounding recurrence after Gamma Knife Radiosurgery (GKRS). Methods: We performed a retrospective chart review of all pediatric AVMs treated with GKRS at our centre. Charts were assessed by two reviewers to identify cases of AVM recurrence after angiographically confirmed obliteration. To contextualize our institutional patterns, we also performed a structured literature review of published data reporting pediatric AVM recurrence after GKRS. Results: Our institutional review revealed two cases of AVM recurrence after angiographically proven cure, and our review of literature identified nine retrospective reviews and three case reports, which in total reported 22 individual cases of recurrence. The recurrence rate in the retrospective reviews ranged from 0 to 18%. Conclusions: The current work illustrates that while AVM recurrence is rare, it is a possible complication of GKRS. There was also a qualitative suggestion that embolization prior to CT increased risk of recurrence. Both these facts should be included in decision-making and patient counselling.

Background: Primary angiitis of the central nervous system (PACNS) is a rare inflammatory condition affecting the parenchymal and leptomeningeal vessels of the CNS. PACNS presenting as a solitary mass lesion (ML-PACNS) constitutes a rare subtype of this pathology. Herein we present the first case reported in Canada of ML-PACNS, presenting with clinical and radiographic findings consistent with a high grade glial neoplasm, as well as a review of the literature on ML-PACNS. Methods: Review of the literature from 1987-2023 was conducted using PubMed to identify features of ML-PACNS and possible treatment paradigms. Results: A number of case reports of ML-PACNS were identified, as well as 6 retrospective analyses of a total of 67 patients. Features such as faster rate of symptom onset, and investigations such as MRI vessel-wall imaging and MR spectroscopy were suggested for identification of ML-PACNS. Treatment was highly variable, but followed guidelines for other neuroinflammatory disorders. Conclusions: Preoperative differentiation between ML-PACNS and CNS neoplasms is difficult due to their similar clinical and radiographic features. However, making this distinction is crucial as PACNS mass lesions can regress entirely with immunosuppressive therapy, potentially obviating the requirement for surgical intervention. Beyond diagnostics, further research is required to establish and validate a treatment paradigm.

Background: Quality of life (QoL) is the awareness of individuals’ well-being in life in physical, personal, mental and social wellbeing and needs to be addressed in brain tumor patients. Methods: A retrospective study conducted in 2017 in a single academic center that included patients diagnosed with brain tumors in a 10 year period. The assessment of the QoL was done using the European Organization for Research and Treatment of Cancer (EORTC), a standardized model (QLQ-C30) that assess several domains (Global Health, Physical function, Role functioning, Emotional Functioning, Cognitive functioning, social functioning and symptoms domain) and Brain cancer model (BN20) to assess symptoms to evaluate all aspects of wellbeing. Results: The total number of patients included in this study is 76 patients with no gender predilection. The most common brain tumor was meningioma by 40% followed by glioma/ others. More than half of the brain tumor patients had a WHO grade I (65%), intermediate grading grade II (15%) and higher grading grade III/IV (20%). The scales and measurements of functioning in life were low in all types of brain tumors. Conclusions: Quality of life in brain tumor patients seemed poor regardless of the type. Further prospective studies are needed to assess QoL worldwide.

Background: Pituitary apoplexy is a rare clinical syndrome resulting from infarction or hemorrhage of a pituitary tumor. Here, we present a large single center retrospective cohort study of patients with apoplexy. Methods: Patients with symptomatic apoplexy treated from January 2000 to October 2022 were isolated from the Halifax Neuropituitary Program’s database, containing prospectively entered data. Patients treated surgically typically presented with vision deterioration or decreased consciousness. Patient demographics, tumor size, endocrinologic values, and clinical outcomes were analyzed. Results: Eighty-three patients met our inclusion criteria. Seventy-two percent of tumours (n=60) were biochemically non-functioning adenomas. Sixty (72.3%) patients were treated surgically, while twenty-three (27.7%) were treated conservatively. At time of presentation, patients treated surgically had a tumor size in maximum dimension of 2.7±1.4 cm versus 1.6±0.5 cm for those treated conservatively (p=0.0003). There were no significant differences in endocrinological values at time of presentation between groups. Fifteen percent (n=9) of patients treated surgically underwent an additional surgery (mean 2.8±2.0 years from index), of which 67% (n=6) were secondary to tumor recurrence. Conclusions: This is one of the largest reported series of apoplexy with long-term follow up. A subset of surgically treated patients will require additional intervention, highlighting the importance of ongoing follow up in this population.

Background: Neurosurgical conditions impose a significant burden on the Canadian healthcare system. This study quantifies the economic impact and explores predictive models for postoperative length of stay. Methods: We analyzed data from the Canadian Institute for Health Information National Health Expenditure Trends database for 2015-2019, focusing on case volumes, healthcare costs, and lengths of stay (LOS) across age groups and conditions. Decision tree models were created to predict total LOS from patient age and average acute LOS. Results: There was a modest increase in case volumes from 6,220 ± 3,103 in 2015 to 6,492 ± 3,240 in 2018, with a slight decrease in 2019. The total estimated hospital costs ranged from 2.27 ± 0.38 million CAD in 2015 to 2.23 ± 0.44 million CAD in 2019. The highest costs were seen in the 18-59 age group, at 2.53 ± 0.43 million CAD. Decision tree models showed high accuracy for predicting LOS in cases like spinal injury (F1-score: 0.98) but were less accurate for interventions with trauma or complications (F1-scores from 0.66 to 0.97). Conclusions: The study delineates the financial demands of neurosurgery in Canada and suggests decision tree models as useful tools for predicting hospital stay, with variable accuracy depending on the case complexity.

Background: Trapped fourth ventricle (TFV) is a rare entity that occurs when the fourth ventricle is obstructed and isolated from the normal cerebrospinal fluid (CSF) circulation. While not always symptomatic, TFV can lead to compression of the cerebellum and brainstem, with potential for serious consequences. Treatment of TFV can be challenging, with options including CSF diversion via shunts versus open or endoscopic fenestrations. In this report, we describe a case of TFV that was managed endoscopically. Methods: A seven-year-old girl with a history of myelomeningocele and hydrocephalus, presented with a change in neurological status. Imaging of the brain and spine showed syringomyelia, markedly dilated ventricles, and a TFV. An endoscopic approach was used to fenestrate the wall of the fourth ventricle. Results: While there was an early favorable outcome, the first fenestration closed over within one month, requiring a repeat endoscopic fenestration. Both procedures were complicated by transient seizures, requiring a pediatric intensive care unit (PICU) admission after the second intervention. Pre- and post-operative clinical and diagnostic imaging findings are reported. Conclusions: Endoscopic fenestration can be an effective treatment option for management of TFV. The patient, family, and treating team should be prepared to deal with acute peri-operative complications that may require PICU management.

Background: Colloid cysts are rare benign lesions of the third ventricle that can cause hydrocephalus and intracranial hypertension. Their primary treatment is surgical removal. Although open surgery presents the best opportunity for total resection of the cyst, there is no consensus regarding the optimal choice between the interhemispheric and the transcortical approaches. We aim to compare these two approaches in regard of the radicality of excision, the recurrence rate, and the surgical imprint. Methods: Retrospective cohort study on all patients who underwent surgical resection of colloid cyst between 2003 and 2023 at CHU de Québec. Data on demographics, symptoms, complications, and imaging was gathered. Results: In a cohort of 28 patients (17 interhemispheric, 11 transcortical), the preliminary results demonstrate prolonging operative time (270min. vs. 187min.) and increasing blood loss (193cc vs 100cc) associated with the interhemispheric approach. Despite these results, the hospitalization duration remains similar (p=0.734). However, the interhemispheric approach results in significantly lower surgery-induced encephalomalacia (1.1cc vs. 4.4cc, p=0.006). Conclusions: The interhemispheric approach could lead to potentially lesser consequences due to the reduced volume of encephalomalacia left by the surgical intervention, at the cost of prolonged operating time and higher blood loss.

Background: Blood loss quantification and management are important facets of cranial surgery, having been linked with adverse outcomes if management is inadequate. While many studies report estimated blood loss (EBL) as an outcome measure, inconsistencies exist in EBL quantification and management strategies Methods: A systematic review of cranial surgery literature on blood loss measurement and management was conducted according to PRISMA guidelines utilizing a novel software platform, Nested Knowledge Results: Initial search yielded 1029 non-duplicated. 107 full-text studies were included. 70% of studies were retrospective. Most common treatment conditions were 41% craniosynostosis (44/107) and 36% tumor (39/107). Most common EBL measurement methods were comparison of pre-operative and post-operative hemoglobin/hematocrit in 46.7% (50/107), anesthesia record in 26.2% (28/107), and surgeon estimation in 9.3% (10/107). 53.3% of studies did not specify a quantification methodology. Blood loss management strategies also varied, with transfusion being the most common method in 64.5% (69/107) of studies Conclusions: EBL quantification and blood loss management remain important clinical and research metrics. Despite this, significant heterogeneity exists in blood loss quantification and management strategies, with most studies providing no data on EBL quantification. Standardization of EBL quantification/reporting should be undertaken to improve comparability and consistency across studies.

Background: The lateral prefrontal cortex (LPFC) is uniquely found in primates and has been associated with contextual learning. This function is thought to be subserved by neurons that are tuned to abstract concepts and the combination of those concepts. LPFC neuron tuning remains to be fully investigated in naturalistic conditions. Methods: Two macaques were trained to perform a context-colour association task while using a joystick to navigate in an X-shaped maze. They were implanted with two 96-channel microelectrode arrays, targeting the LPFC. Mean firing rates were computed and multivariate linear regressions were used to determine tuning. Results: LPFC neurons were tuned to context (12.4%), color position (6.2%), target side (17.2%), and were selective to more than one feature (21.2%). LPFC neurons acquired tuning to task features in an ordered manner, starting with context (130.1±27.4ms), followed by the colour position (296.2±21.4ms) and then target side (493.3±19.3ms). Furthermore, most neurons (54%) changed their tuning over time. Conclusions: We demonstrate that single neurons can encode relevant features embedded in a naturalistic virtual environment. Our results support previous observations that LPFC neurons combine individual features and suggest that these features are also combined temporally. These findings contribute towards understanding the LPFC and have potential practical implications.

Background: There is an absence of studies evaluating longitudinal quality of life (QoL) amongst vestibular schwannomas (VS) with matched tumor and patient characteristics between treatment groups. We present novel findings of 12 yearlong follow-up of patient QoL and symptomatology outcomes in this matched cohort study. Methods: Symptomatology and 36-Item Short Form Health Survey (SF36) between 2000-2017 in VS patients managed at a single tertiary centre was conducted. Radiation (R) and active surveillance (A) groups were matched for tumor size and age against the surgery (S) group. Results: 14 A patients, 24 R patients, 49 S patients met matching and inclusion criteria. Mean age, tumor diameter and follow up was 69.1 years, 21.6mm and 12.0 years respectively. Mental component summary (MCS) scores deteriorated significantly in the radiation group (3.1 S, 3.7 A, -3.5 R, p-value 0.008). Physical component summary scores remained stable at follow up (-0.2 S, 0.00 S, -4.0 R, p-value 0.227). Various symptoms resolved statistically in surgery goup, whereas tinnitus on follow up was higher with radiation (40.8% S, 66.7% R, p-value 0.038). Conclusions: Surgery group demonstrated improvements in long term QoL with good symptom resolution, whilst radiation group demonstrated small but significant deterioration over time.

Background: Intraoperative testing for awake craniotomies requires a multidisciplinary team which may not be available in low-resource settings. We explored the creation of an AI tool for automated testing. Methods: We developed a NodeJS application, EloquentAid (https://www.eloquentaid.com/), for language testing automation. The workflow was as follows: users select an image-based naming task and verbally identify the image in English. Then, the application transcribes the response using OpenAI’s Whisper transcription service. Finally, the application evaluates response correctness. Feedback is provided through auditory and color signals. To assess its reliability, we tested the EloquentAid versus a human rater using a 57-item test based on the Boston Naming Test. Participants were neurosurgery and neurology residents from the Philippines. Qualitative surveys were obtained post-test. Results: A total of 798 observations were recorded (N=14). Human-application agreement was 60.52%. Cohen’s kappa was 0.31 (fair agreement). There were no false positive identifications by EloquentAid. Noun-type was felt to affect human error (i.e. “knocker,” “yolk,” “trellis”). Accent and pronunciation were felt to affect EloquentAid errors. Conclusions: EloquentAid is a promising tool to facilitate intraoperative testing and brain mapping using AI for speech recognition and response evaluation. Preliminary data shows fair human-app agreements. Improvements in test items and pronunciation recognition may be made.

Background: Early placement of a ventricular access device (VAD) may decrease the need for permanent CSF diversion and improve cognitive outcomes in premature infants with intraventricular hemorrhage. In 2019, BC Children’s Hospital implemented a multidisciplinary early intervention pathway for these infants. This study evaluated process and compliance measures related to protocol implementation. Methods: A retrospective quality improvement chart review of enrolled infants was performed. Select measures included time to neurosurgery consult and intervention, compliance with VAD tapping and ultrasound protocols, overall ultrasound resource use, and complications. Results: Sixteen patients were included. Median time to VAD insertion was 6 days (IQR 4-9.5), greater than the 3-day target. Transfer time from peripheral NICUs and access to OR time were found to be important reasons for delay. Patients received a median 92.2% (IQR 85.1-100%) of the ultrasounds required by protocol, with a median of 36.5 (IQR 29-43.25) ultrasounds per patient. VAD tapping was 88.8% (IQR 75.6-94.8%) compliant; most protocol deviations were indicated taps not performed due to technical difficulties. Conclusions: Compliance with the new protocol was satisfactory. Areas for improvement include continued education at peripheral NICU sites to minimize transfer delays, improved access to the OR, and maintenance of technical skills amongst our NICU partners.

Background: Receiving and managing neurosurgical consultations are central to providing quality patient care but are resource intensive processes. As part of an ongoing quality improvement initiative, we conducted a single-institution descriptive analysis of adult neurosurgical consultations. Methods: A retrospective review of prospectively collected consultation records and call schedules from a 12-month period from February 2019 to 2020 was performed. Consults were graded according to disposition (admission for surgery, non-operative admission, additional investigations recommended, opinion without further investigations, unnecessary consult). Results: There were 1916 consultations reviewed, with 52% of calls (n=991) originating outside of our hospital, and 72% (n=1387) coming from an emergency department. Cranial cases made up 64% (n=1230) of consults, while the remaining 36% (n=688) were spine cases. The mean patient age was 60.1±0.4 years. In multinomial logistic regression analysis, age, geographical distance of consulting site, and consult specific variables (neurosurgical subspecialty, inside vs. outside call, emergency department vs. inpatient ward or private office) were associated with consult disposition (p < 0.001). Conclusions: This study provides a descriptive analysis of neurosurgical consultations in Nova Scotia. Results from this study may be used to address inefficacies in the neurosurgical consultation process, including targeted education for consulting physicians.

Background: Burnout is common among health care professionals and can lead to depression and poor patient outcomes. The prevalence of burnout among Canadian neurosurgeons and trainees is yet unknown. Methods: International survey of neurosurgeons and trainees Results: Of total 403 responses, 47 were Canadian respondents (80.9% were male and 14.9% were female). Rate of burnout among Canadian neurosurgeons and trainees was 42.6%; however, there was no significant difference between rate of burnout between Canadian respondents and non-Canadian respondents (35.3%), p=0.33. Rate of burnout among Canadian neurosurgeons and resident/fellow was 40 and 47.1%, respectively, p=0.64. Subgroup analysis showed no difference in rate of burnout between Canadian and non-Canadian practicing neurosurgeons (p=0.34) and Canadian and non-Canadian resident/fellow (p=0.76). Canadian neurosurgeons with work experience of 5-10 years are more likely to have burnout compared to neurosurgeons with more or less work experience (OR 17, 95%CI 1.43-826.22, p=0.005). There was a trend that female Canadian respondents had more burnout than male counterparts (OR 4.2, 95%CI 0.57-47.45, p=0.09). Conclusions: Burnout is not uncommon among Canadian neurosurgeons/trainees. Monitor and supports should be provide to those who are at risk to mitigate burnout and provide resilience.

Background: There is growing evidence supporting the intraoperative use of an antifibrinolytic agent, tranexamic acid (TXA) to limit blood loss; however, use of TXA has not been widely adopted in cranial procedures. We aimed to determine the practice pattern regarding the use of TXA in craniotomy in Canada, and review the literature. Methods: A survey was conducted among the Canadian centres on TXA use during elective craniotomy. Online databases were searched for randomized controlled trials reporting the use of TXA in craniotomy for tumors. The results included the estimated blood loss and the dose used. Results: TXA was not routinely used in elective craniotomy but used selectively in 6 of 15 centres based on risk, intraoperative bleeding, or surgeon preference. The dose was 1 g with or without infusion. 6 studies were identified through literature search. The dose varied between 10–20 mg/kg bolus and 1 mg/kg/hr infusion, or a 2 g bolus alone. All studies reported a significant reduction in blood loss with TXA. Conclusions: We found widely divergent indications for intraoperative TXA use in elective craniotomy throughout Canada. This is in keeping with limited evidence in the literature. Further studies are needed to inform the decision regarding TXA use.

Background: Normal Pressure Hydrocephalus (NPH) is characterized by the clinical triad of dementia, gait disturbance, and urinary incontinence. An initial case series by Hakim and Adams highlighted that all patients exhibited this triad, with only one presenting with fecal incontinence. This study aims to examine the outcomes of individuals experiencing fecal incontinence who have undergone ventriculoperitoneal shunting (VPS). Methods: A systematic review and surgical case series was conducted, involving consecutive adults diagnosed with NPH and treated with VPS between September 2016 and September 2022. Results: In the cohort of 85 patients, the median duration of NPH symptoms was 3.2 years. Gait and balance symptoms were prevalent in all patients, while cognitive, bladder, and bowel symptoms were observed in 85.9%, 91.8%, and 23.5% of cases. No significant differences were noted in age, sex, neurologic diseases presence, or lower gastrointestinal or pelvic pathology. The prevalence of fecal incontinence pre-surgery, within less than 3 months, and 3 months post-surgery were 23.5%, 32.9%, and 17.6%. The systematic review search yielded 515 articles, and 18 included patients with fecal incontinence. Conclusions: The insights gained from the systematic review and cohort offer a comprehensive understanding of the outcomes observed in patients with NPH and fecal incontinence following VPS.

Background: Minimally invasive endoscopic techniques via the transorbital approach (ETOA) have emerged as a promising alternative for addressing skull base tumours. This study aims to showcase our institution’s extensive experience with ETOA, detailing the surgical technique employed and presenting comprehensive patient outcomes. Methods: A retrospective analysis was conducted on data from patients who underwent ETOA within the past five years. Results: Over the study period, 24 ETOA procedures were performed on 21 patients, with an average age of 48.92, 13 of whom were women. The superior orbital corridor was utilized in 95.83% of cases, and in 79.17%, ETOA was complemented by a transnasal approach. Spheno-orbital meningioma accounted for the most common surgical indication (33.33%, n=8), all resulting in vision improvement, followed by lateral frontal sinus mucocele (25%, n=6). The median length of stay was one day, and ETOA achieved the procedure goal in 19 patients. Transient V1 numbness was the primary complication (29.17%, n=7), and 20.83% (n=5) necessitated another surgery. Notably, no mortality was associated with this procedure. Conclusions: Our institution’s experience underscores the notable safety and efficacy potential of ETOA, with 19 out of 21 patients exhibiting positive outcomes, obviating the need for revision surgery in most cases.

Background: Sellar and suprasellar pediatric lesions are uncommon. Endoscopic transnasal transphenoidal surgery (ETTS) is the preferred treatment, but early post-op MRI is hindered by sphenoidal packing. This study aims to assess iMRI safety and efficacy in pediatric ETTS cases. Methods: We performed a retrospective review from Jan 01, 2015 to Dec 31, 2022, evaluating use of iMRI. We determined if the goals of the surgery (biopsy, cyst decompression, subtotal resection, gross total resection) were met, and iMRI’s influence on surgery outcomes. We examined patient age, surgery duration, length of stay, histopathology results, surgical complications, post-op MRIs within 1 month, and tumor progression/recurrence. Results: Over eight years, 20 pediatric ETTS procedures, 14 with iMRI, were conducted. Achieving goals in 13 cases, iMRI prompted extra surgery once. Two adenomas progressed, requiring a second surgery, and craniopharyngioma cases had complications, needing further interventions. Hospital stays varied (1-9 days), with a mean surgery duration of 6 hours and 47 minutes. The study underscores iMRI’s potential impact, stressing the necessity for more research in pediatric transsphenoidal surgeries. Conclusions: While intraoperative MRI in pediatric transsphenoidal surgeries may aid goal verification, this small study doesn’t conclusively demonstrate improved outcomes. Complication rates align with non-IMRI procedures, highlighting the need for further research.

Background: Cerebrospinal fluid (CSF) leak is a common complication of minimally invasive tubular microdiscectomy (MIM). However, it is not known whether patients with CSF leak can be safely discharged home the same day. Methods: This is a retrospective cohort study of patients with incidental durotomy after MIM from January, 2009 to August, 2023. Patient demographic information, surgery information, CSF leak management, and postoperative outcomes were recorded. Results: There were 16 patients (53%) who were admitted to hospital and 14 (47%) patients discharged home the same day post CSF leak. There were no differences in patient demographics between the two groups at baseline. Twenty-nine out of 30 (97%) of the patients had onlay duraplasty, and one (3%) patient was repaired using sutures. The hospitalized group was kept on bed rest overnight or 24 hours. The discharge group was kept on best rest for 2 hours or mobilized immediately after surgery. The average length of admission for the hospitalized group was 2.4 ± 4.0 days. No patients in either group required readmission or revision surgery for CSF leak. Conclusions: Patients with CSF leak post minimally invasive tubular microdiscectomy can be safely discharged home the same day provided that duraplasty or primary repair was performed intraoperatively.