Background: The integration of Artificial Intelligence (AI) in medical education is an area of growing importance. While AI models have been evaluated extensively in multiple-choice question formats, their proficiency in written exams remains to be explored. Methods: Four AI models—GPT-4 (OpenAI), Claude-2.1 (Anthropic), Gemini Pro (Google), and Perplexity 70B (Perplexity)—were tested using the Canadian Royal College Sample Neurosurgery Exam. The written exam covered diagnostic reasoning, knowledge of neurosurgical conditions, and understanding of radiographic imaging techniques. Results: GPT-4 and Perplexity 70B both achieved a score of 68.42%, followed by Claude-2.1 with 60.53%, and Gemini Pro with 57.89%. The models showed proficiency in answering questions that required factual knowledge, such as identifying pathogens in spinal epidural abscess. However, they struggled with more complex diagnostic reasoning tasks, particularly in explaining the pathophysiology behind a sudden rise in blood pressure during surgery and interpreting radiographic characteristics of intracranial abscesses on MRI. Conclusions: The findings indicate that while AI models like GPT-4 and Perplexity 70B are adept at handling factual neurosurgical questions, their performance in complex diagnostic reasoning in a written format is less consistent. This underscores the need for more advanced and specialized AI training, particularly in the nuances of medical diagnostics and decision-making.

Background: Virtual neurological assessments were increasingly used and an important viable option during the COVID-19 pandemic. However, the accuracy of such assessments is unknown. Methods: Clinical records were reviewed in a predominant multiple sclerosis outpatient clinic at an academic teaching hospital from March 23rd 2020 to March 23rd 2021 during the COVID-19 pandemic. Patients assessed during this period were analyzed with an initial virtual assessment compared to subsequent in person evaluations. Results: 1036 patients were included. 27.8% (n=288) of consultations were video and 72.2% (n=748) telephone. A total of 13.8% (n=143) of virtual consultations revealed clinical disparities, specifically 13.5% (n=39) video and 13.9% (n=104) telephone consultations. Of all the 1036 cases, 2.32% (n=24) patients stated they were stable but significant changes were seen on the exam, changing the clinical impression. 11.5% (n=119) stated they were deteriorating virtually but not confirmed when examined in person, with an alternative explanation found. Conclusions: Virtual assessments were accurate in over 85% of the outpatient neurological cases during the pandemic. However, it should be noted that the in person neurological exam led to a change in clinical opinion in 13.8% of assessments. 2.32% patients described clinical stability, but different clinical management plans resulted when significant exam findings were identified.

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.

There are several factors that can cause the excessive accumulation of biofluid in human tissue, such as pregnancy, local traumas, allergic responses or the use of certain therapeutic medications. This study aims to further investigate the shear-dependent peristaltic flow of Phan–Thien–Tanner (PTT) fluid within a planar channel by incorporating the phenomenon of electro-osmosis. This research is driven by the potential biomedical applications of this knowledge. The non-Newtonian fluid features of the PTT fluid model are considered as physiological fluid in a symmetric planar channel. This study is significant, as it demonstrates that the chyme in the small intestine can be modelled as a PTT fluid. The governing equations for the flow of the ionic liquid, thermal radiation and heat transfer, along with the Poisson–Boltzmann equation within the electrical double layer, are discussed. The long-wavelength ($\delta \ll 1$) and low-Reynolds-number approximations ($Re \to 0$) are used to simplify the simultaneous equations. The solutions analyse the Debye electronic length parameter, Helmholtz–Smoluchowski velocity, Prandtl number and thermal radiation. Additionally, streamlines are used to examine the phenomenon of entrapment. Graphs are used to explain the influence of different parameters on the flow and temperature. The findings of the current model have practical implications in the design of microfluidic devices for different particle transport phenomena at the micro level. Additionally, the noteworthy results highlight the advantages of electro-osmosis in controlling both flow and heat transfer. Ultimately, our objective is to use these findings as a guide for the advancement of lab-on-a-chip systems.

Background: Cerebral venous thrombosis (CVT)most commonly affects younger women. Diagnosis may be delayed due to its distinct presentation and demographic profile compared to other stroke types. Methods: We examined delays to diagnosis of CVT in the SECRET randomized trial and TOP-SECRET parallel registry. Adults diagnosed with symptomatic CVT within <14 days were included. We examined time to diagnosis and number of health care encounters prior to diagnosis and associations with demographics, clinical and radiologic features and functional and patient-reported outcomes (PROMS) at days 180&365. Results: Of 103 participants, 68.9% were female; median age was 45 (IQR 31.0-61.0). Median time from symptom onset to diagnosis was 4 (1-8) days. Diagnosis on first presentation to medical attention was made in 60.2%. The difference in time to diagnosis for single versus multiple presentations was on the order of days (3[1-7] vs. 5[2-11.75], p=0.16). Women were likelier to have multiple presentations (OR 2.53; 95% CI1.00-6.39; p=0.05) and longer median times to diagnosis (5[2-8]days vs. 2[1-4.5] days; p=0.005). However, this was not associated with absolute or change in functional, or any patient reported, outcome measures (PROMs) at days 180&365. Conclusions: Diagnosis of CVT was commonly delayed; women were likelier to have multiple presentations. We found no association between delayed diagnosis and outcomes.

Background: Pituitary adenomas are treated with endoscopic surgery, while stereotactic radiosurgery addresses complex cases. Our study highlights AI’s role in accurate segmentation, improving treatment planning workflow efficiency Methods: In a retrospective study at Na Homolce Hospital (January 2010 to October 2022), SRS for pituitary adenomas was analyzed. Data were split 80:20 for training and validation. Using nnU-net, a medical image segmentation tool, a model predicted precise tumor, optic nerve, and pituitary gland segmentation. Accuracy was evaluated quantitatively with Dice similarity coefficient and qualitatively by human experts. The study explored the impact of tumor volume and hormonal activity status on segmentation accuracy. Results: The study comprised 582 and 146 patients in training and validation sets, respectively. The model achieved Dice similarity coefficients of 83.1% (tumor), 62.9% (normal gland), and 78.0% (optic nerve). Expert assessments deemed 41% directly applicable, 31.5% needing minor adjustments, and 27.4% unsuitable for clinical use. Larger tumor volume and non-functioning adenomas correlated with higher accuracy. Including T2 weighted scans improved DSC for optic nerve and normal gland. Conclusions: The study showcases deep learning’s potential in automating pituitary adenoma segmentation from MRI data, particularly excelling in large, hormonally inactive macroadenomas. Encourages collaborative use with clinicians for improved neurosurgical patient care.

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: Infections are hypothesized to trigger certain autoimmune diseases; however, data surrounding incidence trends of pediatric neuro-autoimmune disorders during the COVID-19 pandemic are lacking. Our retrospective study thus assessed the incidence of pre-defined autoimmune disorders diagnosed at the Children’s Hospital of Eastern Ontario in Ottawa, Canada between October 2017 and June 2023. Methods: Inpatient and outpatient charts were queried to identify subjects with neuro-autoimmune disorders or type 1 diabetes (T1D) as a non-neurological autoimmune comparison group. Monthly incidences were calculated and grouped based on three COVID-19 pandemic restriction periods: the pre-restrictions period (October 2017-March 2020), intra-restrictions period (April 2020-June 2022), and post-restrictions period (July 2022-June 2023). Poisson regression models were fit to the incidence data. Results: New diagnoses of neuro-autoimmune disorders and T1D were identified in 86 and 591 subjects, respectively. Incidence of neuro-autoimmune disorders decreased significantly during the intra-pandemic restrictions period when compared to the pre-pandemic period (IRR=0.56, 95% CI: 0.32-0.93, P<0.05). Albeit not statistically significant, the incidence then increased to higher than pre-pandemic levels during the post-restrictions period. T1D showed no significant changes in incidence. Conclusions: Incidence of neuro-autoimmune disorders, but not T1D, decreased during COVID-19 pandemic restrictions, which may be due to reduced transmission of key infectious triggers.

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: Necrotizing anti-HMGCR myopathy is rare in children. Pediatric cases are not typically associated with statin use or malignancy. Methods: Retrospective chart review (January 2009 to December 2023) identified cases of anti-HMGCR myopathy at our hospital. Results: Two patients were identified. Patient A, presented at 8 yo with a 2 year history of proximal muscle weakness. His CK was 4,840 U/L (normal <205 U/L) with a high anti-HMGCR antibody titre. His Childhood Myositis Assessment Scale (CMAS) score was 33/52. Monthly IVIG was started and his muscle strength and CK improved. Two years later, weekly methotrexate was started for persistent mild CK elevation (602 to 869 U/L). At 11 years old, 3 years after diagnosis, his CMAS score was 47 and he could participate in soccer with mild fatigue. Patient B, presented at 8 yo with acute proximal weakness, rash and CMAS 13/52. His CK was 20,185 U/L with elevated anti-HMGCR antibody titre. He received oral corticosteroids, weekly methotrexate and monthly IVIG. At 10 yo, 2 years after diagnosis, he is asymptomatic with CMAS 51. He is maintained on methotrexate monotherapy. Conclusions: Anti-HMGCR antibody myopathy requires prompt diagnosis to obviate muscle necrosis and long-term complications. Our patients showed clinical and CMAS improvement with treatment.

Background: Stereotactic laser amygdalohippocampotomy (SLAH) has recently been shown to be comparable to traditional temporal lobectomy procedures. The ideal extent and volume of laser ablations remains an area of investigation Methods: 65 patients treated with SLAH for MTS were considered in this retrospective study. Manual segmentations of ablations were created using post-procedure T1-MRI scans. Ablations were assessed in relation to whether they crossed the coronal plane of the superior lateral mesencephalic sulcus (LMS), the extent to which ablation crossed this landmark, and extent of ablation of the uncus. Analysis of was done with binary categorization of 12-month Engel classification score. Results: Distance of ablation posterior to the coronal plane of the LMS was not associated with better surgical outcome (Engel class 1: 6.32 ± 4.16 mm; Engel class 2-4: 7.93 ± 3.75mm; (p = 0.099)). Ratio of ablations extending posterior to the LMS was 0.82 (SD = .39) in Engel 1 patients, and 0.90 (SD = 0.3) in Engel 2-4 patients; (p = 0.370). Volume of ablation showed little correlation with outcome (Engel class 1: 6064 ± 2128 mm3; Engel class 2-4: 5828 ± 3031 mm3; (p=0.239)). Ablation of the uncus showed a strong association with better surgical outcome (Engel class 1: 0.71(SD = 0.31); Engel 2-4: 0.37 (SD = 0.36); p <0.001). Conclusions: Contrary to current practice, extension of ablation posterior to the LMS did not demonstrate improved outcome.

Background: Trofinetide significantly improved core symptoms of Rett syndrome (RTT) with an acceptable safety profile in LAVENDER. Here, we report the safety and efficacy results of LILAC and LILAC-2, open-label extension studies of LAVENDER. Methods: Females with RTT, aged 5–21 years, received twice-daily, oral trofinetide in LILAC for 40 weeks. Participants who completed LAVENDER and LILAC continued trofinetide in LILAC-2, a 32-month extension study. Safety assessments included the incidence of adverse events (AEs). Efficacy endpoints included the Rett Syndrome Behaviour Questionnaire (RSBQ) and the Clinical Global Impression–Improvement (CGI-I) scale. Results: Overall, 154 patients were enrolled in LILAC. The most common AEs were diarrhea (74.7%) and vomiting (28.6%). The mean (standard error [SE]) change from the LAVENDER baseline to Week 40 in the LILAC study in RSBQ was -7.3 (1.62) and -7.0 (1.61) for participants treated with trofinetide and placebo in LAVENDER, respectively. Mean (SE) CGI-I scores compared with the LILAC baseline at Week 40 were 3.1 (0.11) and 3.2 (0.14) for patients treated with trofinetide and placebo in LAVENDER, respectively. Similar safety and efficacy trends were observed in LILAC-2. Conclusions: Trofinetide continued to improve symptoms of RTT in LILAC and LILAC-2 with a safety profile consistent with LAVENDER.

Background: The diagnosis of leptomeningeal metastatic disease has major prognostic implications. We report 13 patients with a radiologically distinct, focal, enhancing leptomeningeal lesion on brain MRI mimicking leptomeningeal metastatic disease. Methods: These patients were assessed at University Health Network between January 2001 and December 2023. Results: Median age was 68 years and 10 patients were women. All patients had brain MRI including contrast-enhanced T2-weighted FLAIR and T1-weighted spin echo sequences. MRI in all patients showed a focal enhancing lesion along the leptomeningeal surface of the brain. The MRI exams were reported as possible metastatic disease for the majority (9/13) of patients. Each lesion was curvilinear rather than sheet-like, and some consisted of multiple connected/branching curvilinear structures with the appearance of abnormal vessels. Some lesions had visible connection with a nearby cortical vein. The lesions were distinct from normal blood vessels. Follow-up contrast-enhanced brain MRI for 8/13 patients at a median of 3.9 years showed all lesions were unchanged over time. Conclusions: We describe a distinct kind of focal, enhancing leptomeningeal lesion on brain MRI that mimics metastatic disease. These lesions are likely a type of low-flow vascular anomaly. Their curvilinear/branching shape and intense enhancement particularly on T2-weighted FLAIR images distinguishes these lesions from tumor.