Background: An estimated 27-69 million individuals worldwide sustain a mild Traumatic Brain Injury (mTBI) each year, making it an important public health concern. Many victims experience post-injury neuropsychological issues such as anxiety and depression, which are associated with more post-concussive symptoms and worse functional outcomes. We sought to determine a systematic process to document the presence of anxiety and depression symptoms in mTBI patients to prevent negative impacts on their recovery. Methods: We administered the Generalized Anxiety Disorder-7 (GAD-7) and Center for Epidemiologic Studies Depression Scale Revised (CESDR-10) questionnaires, no more than three months after injury, to screen for these symptoms. A retrospective chart review was performed for 328 patients from the Montreal General Hospital mTBI Clinic who either received these questionnaires (N=143, Mage=40.36, SDage=15.557, Nfemale=90, Nmale=53) or did not (N=185, Mage=41.17, SDage=16.449, Nfemale=114, Nmale=71). The number of interventions received between groups were compared using ANOVA. Results: Patients who received the questionnaires (M=1.34, SD=0.978) were referred to significantly more interventions than those who did not (M=0.90, SD=0.876, p<0.001) and the rate of referral positively correlated with GAD-7 and CESDR-10 scores. Conclusions: Screening for symptoms of anxiety and depression post mTBI helps clinicians refer patients to the appropriate resources, which in turn should improve outcome.

Background: Employment and personal income loss after traumatic brain injury (TBI) is a major source of post-injury stress and barrier to societal reintegration for affected patients. We sought to quantify the labor market implications for tax-filing adult TBI survivors. Methods: We performed a matched difference-in-difference analysis using a national retrospective cohort of working adult TBI survivors injured between 2007-2017. Linear and logistic mixed effects regressions were used to estimate the magnitude of personal income loss and proportion of patients displaced from the workforce in the three post-injury years (Y+1 to Y+3). Results: Among 18,050 patients identified with TBI, the adjusted average loss of personal annual income was $-7,635 dollars in Y+1 and $-5,000 in Y+3. An additional -7.8% individuals were newly unemployed compared to the pre-injury baseline. For mild, moderate, and severe TBI subgroups, income loss was $-3354, $-6750, and $-17375 respectively in Y+3; the proportion of newly unemployed individuals in Y+3 was 5.8%, 9.2%, and 20% lower than baseline. We estimated 500 million dollars of incurred labor markets losses related to TBI in Canada. Conclusions: This work represents the first national cohort data quantifying the labor market implications of TBI. These results may be used to inform post-injury care pathways and vocational rehabilitation.

Background: Despite the utility of administrative health data, there remains a lack of patient-centered outcome measures to meaningfully capture morbidity after traumatic brain injury (TBI). We sought to characterize and validate days at home (DAH) as a feasible measure to assess population-level moderate to severe TBI (msTBI) outcomes and health resource utilization. Methods: We utilized linked health administrative data sources to identify adults with msTBI patients presenting to trauma centers in Ontario injured between 2009-2021. DAH at 180 days reflects the total number of days spent alive and at home excluding the days spent institutionalized in acute care, rehabilitation, inpatient mental health settings or post-acute readmissions. Construct and predictive validity were determined; we additionally estimated minimally important difference (MID) in DAH180days. Results: There were 6340 patients that met inclusion criteria. Median DAH180days were 70 days (interquartile range 0-144). Increased health resource utilization at baseline, older age, increasing cranial injury severity and major extracranial injuries were significantly associated with fewer DAH180days. DAH180days was correlated to DAH counts at 1-3 years. The average MID estimate from anchor-based and distribution-based methods was 18 days. Conclusions: We introduce DAH180days as a feasible and sufficiently responsive patient-centered outcome measure with construct, predictive and face validity in an msTBI population.

Background: Chronic subdural hematoma (CSDH) is a common neurosurgical condition which can be treated with surgical evacuation. A significant percentage of CSDH patients are on antiplatelet or anticoagulation therapy at baseline which may influence risk of recurrence and postoperative thromboembolic events Methods: A search was conducted in MEDLINE (1946 to April 6, 2023), Embase (1974 to April 6, 2023), and PubMed (up to April 6, 2023) on preoperative use of antiplatelet or anticoagulation therapy and outcomes following surgical evacuation of CSDH. Results: Our literature includes 14,410 patients ifrom 42 studies, with 3218 (22%) in the antiplatelet (AP) group, 1731(12%) in the anticoagulation (AC) group, and 9537 (66%) in the no antithrombotics (NA) group. The AP group had significantly higher recurrence compared to NA (OR = 1.21, 95% CI = 1.04 to 1.40, p = 0.01). The AC group also had significantly high recurrence compared to NA (OR = 1.39. 95% CI = 1.15 to 1.68, p = 0.0007). However, being on any antithrombotic therapy is also associated with significantly higher thromboembolic events (OR 5.41, 95% CI 3.16 to 9.26, p < 0.00001). Conclusions: Patients on antithrombotic therapy have both higher recurrence and higher thromboembolic risk compared to patients not on antithrombotic therapy.

Background: Near-infrared spectroscopy (NIRS) regional cerebral oxygen saturation (rSO2) based cerebrovascular reactivity (CVR) indicies have enable the entirely non-invasive continuous monitoring. This study aims to compare CVR in those recovering from moderate/severe TBI to a health control group. Methods: In this prospective cohort study the cerebral oxygen CVR index, COx_a (using rSO2 and arterial blood pressure), was measured in subjects with moderate/severe TBI at follow-up. COx_a was also measured in a group of healthy controls. CVR was compared within and between these groups using conventional statistics. Results: A total of 101 heathy subject were recruited for this study along with 29 TBI patients. In the health cohort COx_a was not statistically different between males and females or in the dominate and non-dominate hemisphere. The TBI cohort, COx_a was not statistically different between first and last available follow up. Surprisingly, CVR as measured by COx_a was statistically better in those recovering from TBI than in the healthy cohort. Conclusions: In the prospective cohort study, CVR as measured by NIRS based methods, was found to be more active in those recovering from TBI than in a healthy cohort. This study may indicate that, in those that survive TBI, CVR may be enhanced as a neuroprotective measure.

Background: Subdural and subgaleal drains are equally effective after burrhole craniostomy for chronic subdural haematoma, however the optimal location of drains after minicraniotomy is not clear. As such we present the first study to assess this. Methods: Consecutive patients undergoing minicraniotomy for cSDH between 2019 and 2023 at a single institution were included. Subgaleal drains were placed exclusively by a single surgeon with the rest of the department utilising standard subdural drains. Cases were stratified by drain location. Primary outcomes included changes in functional status (Modified Rankin Score, mRS) at 3 months from preoperative baseline. Results: A total of 137 patients were included, of which 24.6% received subgaleal drains. Discharge home was higher in the subgaleal group compared to subdural group (79.4% vs 57.3%, p=0.02). Subgaleal drain location (p<0.0001) and better preoperative GCS (p=0.01) were predictors of improved 3 month mRS. Worse premorbid mRS (p=0.002), subdural drain (p=0.004), and decreased consciousness at presentation (p<0.002) were predictors of not being discharged home. Surgical recurrence was lower in the subgaleal group than the subdural group (2.9% vs 13.6%, p=0.12), but not statistically significant. Conclusions: Subgaleal drains are associated with shorter hospitalisation, greater chance of discharge home, and better functional outcomes than subdural drains.

Background: The formation of pial-pial collateral network aneurysms due to carotid occlusion is a rare neurological phenomenon. This case details a 69-year-old male who developed a pial-pial collateral network aneurysm secondary to left internal carotid artery occlusion, leading to intracranial hemorrhage. Methods: The patient presented with altered consciousness due to left temporal intracerebral hemorrhage, subdural hematoma, and intraventricular hemorrhage. Cerebral angiography revealed an occluded left internal carotid artery, with superficial temporal artery (STA) and superior orbital artery anastomosis, and extensive pial-pial collaterals from the posterior temporal artery. A 4 mm aneurysm arising from this collateral network was identified. Surgical intervention involved a left temporal craniectomy and excision of the aneurysm, prioritizing the preservation of the STA. N.B., Informed patient consent was obtained in this study. Results: Successful aneurysm removal and preservation of collateral pathways were confirmed by postoperative imaging. The patient exhibited rapid neurological improvement; by postoperative day (POD) one, the patient showed limited response to stimuli. He was extubated by POD4 and discharged on POD27, where he conversed well, was independently ambulatory, and needed minimal to no assistance in activities of daily living. Conclusions: This case highlights the need for careful preoperative planning and intraoperative precision, especially in preserving vital collateral vascular pathways.

Background: Managing unruptured cerebral aneurysms involves monitoring or repair, with complex factors influencing decision-making. Geographical distance from treatment centers is an understudied factor. This study explores a potential relationship in Nova Scotia between proximity to the sole neurosurgical center in Halifax and aneurysm management. Methods: A prospectively collected neurosurgery database was used to identify all adults seen for unruptured cerebral aneurysm between Jan 1, 2015 - Dec 31, 2020. Demographic data, aneurysm characteristics, follow-up and treatment information were collected. Univariate and multivariate analyses assessed management differences based on geography, controlling for relevant factors including aneurysm size and location. Results: Among 390 patients, 40% were in Halifax, and 60% were outside. No significant difference existed in elective repair (34% vs. 26%, p=0.143) and imaging follow-up frequency (2.26 vs. 2.22, p=0.858). In-person follow-up was higher within Halifax (1.83 vs. 1.43, p=0.008), while virtual follow-up was significant outside Halifax (1.44 vs. 1.01, p=0.003). Overall, in-person and elective repair frequencies declined with the COVID-19 peak, whereas virtual follow-up increased. Conclusions: No significant association was found between patient location and repair decisions. Patients in closer proximity had more in-person follow-ups, while those farther away had more virtual follow-ups. The COVID-19 pandemic affected follow-up frequencies universally.

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.