Background: This study aimed to describe the technical characteristics and clinical efficacy of intracranial-to-intracranial (IC-IC) bypass for the treatment of complex intracranial aneurysms. Methods: We retrospectively reviewed all patients with aneurysms who underwent a preplanned combination of surgical or endovascular treatment and IC-IC bypass at our institution between January 2006 and September 2023. IC-IC bypass techniques included four strategies: type A (end-to-end reanastomosis), type B (end-to-side reimplantation), type C (in situ side-to-side anastomosis), and type D (IC-IC bypass with a graft vessel). Results: We performed the type A strategy on five patients (50.0%), type B on one (10.0%), type C on one (10.0%), and type D on three (30.0%). During a mean period of 68.3 months, good clinical outcomes (modified Rankin Scale score, 0-2) were observed in all patients. Follow-up angiography demonstrated complete aneurysmal obliteration in all patients and good bypass patency in nine of ten patients (90.0%). Conclusions: The treatment of complex aneurysms remains a challenge with conventional surgical or endovascular treatments. IC-IC bypass surgery is a useful technique, associated with favorable clinical outcomes, for treating complex aneurysms.

Background: Neurosurgery is a long and arduous training program, and the demands of neurosurgical training have led to resident burnout prevalence ranging from 11-67%, attrition, and suicide. We aimed to assess whether implementation of a weekly self-assessment tool with optional psychological counselling improves neurosurgical resident quality of life. Methods: We performed a one year prospective cohort study including 14 Calgary (intervention group) and 12 Toronto/Winnipeg residents (control group). Calgary residents utilized a mobile application (“HONE”) weekly, and all residents responded to questionnaires at baseline, midpoint and endpoint: EQ-5D-5L, Maslach Burnout Inventory (MBI), and Mayo Clinic Well-being Index (WBI). Between and within group results were compared using two-tailed t-tests. Results: Pooled baseline scores were comparable to population norms, with increased mean MBI depersonalization scores (10.28 versus 7.12, p=0.033), and more WBI “at risk” scores compared to normative data. There were no baseline differences between cohorts. EQ-5D-5L, MBI, and WBI scores were comparable between and within cohorts at all three time points. Three intervention group residents accessed psychological counselling, totalling ten sessions. Conclusions: Weekly use of the HONE application did not impact resident quality of life, although multiple residents displayed help-seeking behaviours. HONE provided tangible data for the program director to track trends in team well-being.

Background: Degenerative Cervical Myelopathy (DCM) is a progressive condition causing cervical spinal cord injury. Disease severity is commonly assessed using the modified Japanese Orthopedic Association (mJOA) score, yet clinical guidelines do not integrate pain—a key symptom—in evaluations. This meta-analysis examines the relationship between pain scores and quality of life outcomes (QOL) in surgical DCM patients. Methods: A comprehensive literature search using MEDLINE, Web of Science, and Embase identified 73 studies. Data regarding pain scores (VAS/NRS) and QOL outcomes (SF-12, SF-36) were extracted by 2 independent reviewers and all conflicts were resolved by the senior author. The number of patients analyzed in the studies included was 929. Results: Meta-regression identified no significant relationship between pain and SF-36 preoperatively but found a significant negative correlation at 3 months (r = -0.67, p<0.05), 6 months (r = -0.65, p<0.05), 1 year (-0.63, p<0.05), and 2 years (r = -0.62, p<0.05). Conclusions: Our results indicate a strong relationship between postoperative pain and QOL among patients with DCM. Surgeons and care teams should prioritize optimal pain management postoperatively for patients with DCM.

Background: Ocular point-of-care ultrasound (POCUS) may be a clinically useful method to evaluate shunt dysfunction for children with hydrocephalus in the emergency department (ED). We assessed whether a change in optic nerve sheath diameter (ONSD) from prior asymptomatic baseline is associated with shunt failure. Methods: This prospective single center cohort study included asymptomatic shunted children (age 0-18 years). Baseline ocular POCUS was performed in the outpatient neurosurgery clinic; a second POCUS was performed if the patient subsequently presented to the ED with symptoms of shunt failure. Shunt failure was defined by intraoperative confirmation of inadequate CSF flow through the shunt within 96 hours from ED presentation. Results: The primary outcome of intra-operatively confirmed shunt failure occurred in 14/76 (18%) ED patient presentations. ΔONSD in patients with and without shunt failure was 0.89mm and 0.16mm respectively; the mean difference was 0.73mm (95%CI: 0.34-1.12), p=0.0012. The area under the receiver operating characteristic curve was 0.86, with an optimal cutoff of ≥+0.4mm, corresponding to sensitivity of 0.93, specificity of 0.73, PPV of 0.43, NPV of 0.98. Conclusions: ΔONSD was strongly associated with shunt failure. We found ΔONSD of <+0.4 in symptomatic children with CSF shunts may identify a population that had low likelihood of true shunt failure.

Background: Meningiomas exhibit considerable heterogeneity. We previously identified four distinct molecular groups (immunogenic, NF2-wildtype, hypermetabolic, proliferative) which address much of this heterogeneity. Despite their utility, the stochasticity of clustering methods and the requirement of multi-omics data limits the potential for classifying cases in the clinical setting. Methods: Using an international cohort of 1698 meningiomas, we constructed and validated a machine learning-based molecular classifier using DNA methylation alone. Original and newly-predicted molecular groups were compared using DNA methylation, RNA sequencing, whole exome sequencing, and clinical outcomes. Results: Group-specific outcomes in the validation cohort were nearly identical to those originally described, with median PFS of 7.4 (4.9-Inf) years in hypermetabolic tumors and 2.5 (2.3-5.3) years in proliferative tumors (not reached in the other groups). Predicted NF2-wildtype cases had no NF2 mutations, and 51.4% had others mutations previously described in this group. RNA pathway analysis revealed upregulation of immune-related pathways in the immunogenic group, metabolic pathways in the hypermetabolic group and cell-cycle programs in the proliferative group. Bulk deconvolution similarly revealed enrichment of macrophages in immunogenic tumours and neoplastic cells in hypermetabolic/proliferative tumours. Conclusions: Our DNA methylation-based classifier faithfully recapitulates the biology and outcomes of the original molecular groups allowing for their widespread clinical implementation.

Until recently, much work on the process and impact of compensated emancipation in the British Empire tended to exclude the Cape Colony, instead focusing on Britain and the Caribbean. This analysis of the Cape Town agents who acted as intermediaries in the business of compensation reintegrates the Cape Colony into these discussions. Using Thomson, Watson & Co.’s account book, this article details how the Cape Town firm used its networks within the colony and in London to profit from the business of compensation. The firm handled over 800 claims from Cape Colony principals, purchased them on its own and others’ accounts, and remitted them to several associates in London for collection. This article contributes a new perspective to the growing literature on the process and impact of compensated emancipation and raises questions about the role of slavery and emancipation in the development of commercial and financial capitalism in South Africa.

Discussions of sample-based music are traditionally single-authored, despite the frequency of multi-genre content found within this repertoire. This article builds a case for a new approach for future analyses, justified by highlighting repertoire that embeds samples from different genres, times, and cultures and that calls upon a variety of disciplinary expertise to attend to these disparate contents. Multi-voice commentary is an approach that includes insider voices to speak to the content of sample-based music, building a reception network that runs counter to single authorial modes, broadening the narrative around sample-based music and its lineage. Certain sample-based works are most in need of this new approach, based on situations of ‘sampling up’, ‘down’, or ‘sideways’, tendencies developed from Nader’s concept of ‘studying up’ and Walser’s writings on ‘appropriations from below’. Theoretical ideas from Fish and Barthes are also brought into this discussion to further the case for a multiplicity of readings.

Background: Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease process that represents a significant health shock for thousands of patients each year. Return to work outcomes and associated factors require evaluation to counsel patients and identify domains on which to focus clinical efforts. Methods: A systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines was performed using MEDLINE, EMBASE and Cochrane databases from inception to February 2024. Proportion of patients returning to work was collected from included studies. Odds ratios were pooled from studies evaluating the association between pre-rupture demographic variables, post-rupture clinical variables and return to work following aSAH. Results: Literature search yielded 3861 studies, of which 40 studies were included in the final analysis for a total of 6888 patients. On average, 55% (SD 17%) of all patients returned to work after an aSAH. Female sex (male sex OR 1.75), high grade aSAH on presentation (OR 0.30), and need for permanent CSF diversion (OR 0.50) are significantly associated with unemployment after aSAH. Conclusions: Female sex, high grade presentation, and permanent CSF diversion are associated with unemployment after aSAH. About half of all patients that experience aSAH return to work.

Background: Studies have found similar rates of functional independence for men and women after endovascular thrombectomy (EVT). Less is known regarding EVT-related procedural complications and symptomatic intracerebral hemorrhage (sICH) between sexes. Methods: Using the OPTIMISE registry including data from 20 comprehensive stroke centers across Canada between 1/1/2018 and 12/31/2022, we performed a retrospective descriptive analysis of patients divided between men and women. Hemorrhagic transformation on follow-up imaging with associated clinical deterioration was required to define sICH. Results: 3631 patients were included (1778 men and 1853 women) for analysis. Female patients were older (71.8±14.6 vs 68.0±13.1 years, p<0.001). There were no differences in sICH rates (2.5% men vs. 2% women, p= 0.388}. Procedural complication rates were not different between men and women (5.8 vs 5.6% p=0.76): dissection {26 (1.5%) vs. 30 (1.6%), p=0.804}, perforation {11 (0.6%) vs. 7 (0.4%), p=0.426}, embolization {25 (1.4%) vs. 25 (1.3%), p=0.996} and arterial access complications {45 (2.5%) vs. 43 (2.3%), p=0.761}. Conclusions: In this large multicentre registry of stroke patients undergoing EVT, men and women had similarly low and reassuring rates of sICH and procedural complications. This complements previous data showing similar functional outcomes for men and women after EVT.

Background: Endonasal endoscopic odontoidectomy (EEO) is a well-established method for treating symptomatic ventral compression at the cranio-cervical junction (CCJ). This study aims to review the clinical outcomes of patients undergoing EEO, focusing on clinical presentation, progression, and prognostic factors. Methods: We retrospectively analyzed data from patients who underwent EEO between October 2001 and October 2023. Information was collected on demographics, indications, reconstruction techniques, complications, fusion requirements, readmission rates, and outcomes. Results: Fifteen patients were included, with 60% classified as ASA class III. The majority presented with myelopathy (80%). Indications for surgery included basilar invagination, Chiari malformation, and rheumatoid arthritis. The mean blood loss was 317 ml. No perioperative lumbar drains were used, and 26.7% of patients had intraoperative CSF leaks, though no postoperative leaks were noted. A pedicled nasal flap was required in 66.7% of cases. Fourteen patients needed occipitocervical fusion, and six were readmitted within 30 days due to bulbar deficits. At the last follow-up, 86.6% of patients experienced symptom improvement. A significant association was found between decompression extent and symptomatic improvement (p=0.003). Conclusions: EEO is a safe and effective method for CCJ decompression, often accompanied by posterior cervical stabilization, with most patients showing symptomatic improvement and a low complication rate.

Background: Telemedicine evaluation for treatment of acute stroke patients with IV thrombolysis has been shown to be beneficial. Its usefulness for the evaluation of patients transferred from a primary stroke centre (PSC) to a comprehensive stroke centre (CSC) for endovascular thrombectomy (EVT) is less well defined. Methods: We retrospectively analyzed the Canadian OPTIMISE registry which included data from 20 comprehensive stroke centers across Canada between January 1, 2018, and December 31, 2022 to compare treatment metrics and early outcomes between two groups: patients evaluated by telemedicine (TM) and patients evaluated in person (non-TM) at the PSC prior to CSC transfer. Results: We included 3317 patients who were transferred from a PSC to a CSC for: 888 TM and 2429 non-TM. There were no major differences in baseline characteristics, including intravenous thrombolysis administration, though the TM group included more men. TM patients had longer onset-to-puncture times (441 vs 403 minutes, p<0.001) and higher symptomatic intracerebral hemorrhage (sICH) rates (7.4% vs 3.7%, p<0.001), but CSC door-to-puncture times and successful recanalization rates did not differ. Conclusions: Patients transferred to a CSC for EVT first evaluated by TM had similar characteristics to those evaluated in person at the PSC, but longer onset-to-puncture times and higher sICH rates.

Background: Surgical robotics can minimize the discrepancy between surgical preoperative plan and postoperative execution. This work explores the performance of a supervisory-control architecture robot (8i Robotics) for autonomous pedicle instrumentation in both an open and MIS workflow in a poricne model, as well as guidance accuracy in humans. Methods: 11 porcine subjects (7 open, 4 minimally invasive) had clinical grading assessment of pedicle screw placement. 3 of the open cohort had detailed precision analysis. Post-operative CT assessed screw location. Euclidean error was calculated at screw head and screw tip and confidence ellipses generated. In two human patients, guidance accuracy was compared to existing neuro-navigation. Results: All screws where GRS A. There was no clinical difference between clinical assessment of MIS vs Open workflow. Mean tip and head Euclidean error where 2.47+/-1.25mm and 2.25+/-1.25mm respectively. Guidance was successfully obtained in both human cases. Conclusions: 100% of screws obtained satisfactory clinical grading. This demonstrates the capability of a supervisory controlled robotic pedicle screw insertion robot in both open and minimally invasive workflow. Furthermore, initial guidance was feasible in living human patients with comparable agreement to current navigation. This work demonstrates exciting promise for the future of autonomous surgical robotics.

Background: Meningiomas are the most common intracranial extra-axial lesion. Reports of meningioma regression exist, often in the context of known hormonal or vascular fluctuations, though very few describe complete resolution. Though rare, extra-axial mimics such as lymphoma and chloroma may also spontaneously regress. Methods: Electronic medical records were used to access patient information in accordance with our local ethics review board. Results: A 29-year-old male presenting with new onset seizures was found to have a 22.7 x 26.6 mm left temporal extra-axial lesion, radiologically consistent with meningioma. Due to wait times and patient preference, repeat pre-operative imaging was not available prior to surgical resection 13 months later, though an interim CT had confirmed persistence of the tumour’s size 1 month after diagnosis. Decision was made to proceed with resection; however, intraoperatively, no lesion was identified. Post-operative imaging demonstrated complete disappearance of the lesion, and follow-up imaging has shown no recurrence. Conclusions: This case highlights the possibility of spontaneous resolution of extra-axial lesions and emphasizes the importance of serial imaging prior to resection.

Background: This study aimed to identify risk factors for postoperative cerebrospinal fluid (CSF) leaks and assess their outcomes following endoscopic endonasal approach (EEA) for resection of skull base tumors. Methods: A retrospective review was conducted of patients who underwent EEA for resection of intradural pathology between October 2001 and October 2023. Data on demographics, approach type, reconstruction technique, tumor pathology, complications and outcomes were analyzed. Results: A total of 542 patients were included, with 80.1% undergoing surgery for sellar or suprasellar pathology. Lumbar drains were used in 14.9%, and dural sealants in 57.7%. Forty patients (7.3%) developed postoperative CSF leaks, with the highest rate in sellar or suprasellar lesions (5.9%). CSF leaks were associated with longer hospital stays (p < 0.001), higher 30-day readmission rates (p < 0.001), increased sepsis risk (p = 0.021), and higher rates of diabetes insipidus (p < 0.001). Lumbar drains increased the incidence of CSF leaks (p = 0.021), while nasoseptal flap reconstruction reduced leak rates (p = 0.0015). Higher BMI and intraoperative CSF leaks were also significant risk factors (p = 0.001) Conclusions: CSF leaks are associated with increased complications and extended hospital stays, highlighting the need for vigilant intraoperative monitoring and targeted strategies.

This paper discusses the development of synthetic cohomology in Homotopy Type Theory (HoTT), as well as its computer formalisation. The objectives of this paper are (1) to generalise previous work on integral cohomology in HoTT by the current authors and Brunerie (2022) to cohomology with arbitrary coefficients and (2) to provide the mathematical details of, as well as extend, results underpinning the computer formalisation of cohomology rings by the current authors and Lamiaux (2023). With respect to objective (1), we provide new direct definitions of the cohomology group operations and of the cup product, which, just as in the previous work by the current authors and Brunerie (2022), enable significant simplifications of many earlier proofs in synthetic cohomology theory. In particular, the new definition of the cup product allows us to give the first complete formalisation of the axioms needed to turn the cohomology groups into a graded commutative ring. We also establish that this cohomology theory satisfies the HoTT formulation of the Eilenberg–Steenrod axioms for cohomology and study the classical Mayer–Vietoris and Gysin sequences. With respect to objective (2), we characterise the cohomology groups and rings of various spaces, including the spheres, torus, Klein bottle, real/complex projective planes, and infinite real projective space. All results have been formalised in Cubical Agda, and we obtain multiple new numbers, similar to the famous ‘Brunerie number’, which can be used as benchmarks for computational implementations of HoTT. Some of these numbers are infeasible to compute in Cubical Agda and hence provide new computational challenges and open problems which are much easier to define than the original Brunerie number.

In this paper, we study the following high-order elliptic equation involving the GJMS operator:

\begin{align*}\alpha P_{\mathbb{S}^n}v_{\alpha}+2Q_{g_{\mathbb{S}^n}}=2Q_{g_{\mathbb{S}^n}}e^{nv_{\alpha}}.\end{align*}

We establish that if α > 1 and $n\geq3$ or if $\alpha\in (1-\epsilon_0, 1)$ with $n=2m\geq4$, then $v_{\alpha}\equiv0$. As an application, we present a new proof of the classical Beckner inequality.

Peloids are natural therapeutic muds or clays used in balneotherapy and other health treatments. The aim of this study is to prepare and qualify three artificial peloids by maturation for 360 days of some Tunisian smectitic clays with a naturally chlorinated sodic mineral water from a spring in Korbous, Tunisia. This was done to improve our understanding of the behaviour of these clays and the physicochemical changes that affect the clays during maturation, with the purpose of providing suitable raw materials as a solid phase for peloid preparation. The results showed that parameters such as mineralogy, geochemistry, granulometry, cation-exchange capacity, consistency parameters (Atterberg limits and plasticity index), specific surface area, cooling kinetics and pH are all affected by the geochemistry of the thermal water used during maturation. Mineralogical modifications mostly concern the clay minerals’ contents, particularly smectite, and subordinately the dissolution of gypsum and the neoformation of halite. The observed improvements to the plasticity index and cooling kinetics can be explained by the ability of water molecules, and especially cations, to diffuse into the clay particles. The main exchangeable cations are Na+ and Ca2+, along with Mg2+ and K+, which promote swelling and increase water retention and consequently retention of heat in thermal spa treatments. The chemical composition of the major elements is closely linked to the mineralogical compositions of the clays, and also to the chemical composition of the thermal water used in their maturation. The safety profiles of the peloids obtained at different maturation times were evaluated, particularly regarding their content of potentially toxic elements such as arsenic.

In this article, we prove the local-in-time existence of regular solutions to dissipative Aw–Rascle system with the offset equal to gradient of some increasing and regular function of density. It is a mixed degenerate parabolic-hyperbolic hydrodynamic model, and we extend the techniques previously developed for compressible Navier–Stokes equations to show the well-posedness of the system in the $L_2-L_2$ setting. We also discuss relevant existence results for offset involving singular or non-local functions of density.

Background: Tuberous Sclerosis Complex (TSC) is a multisystemic neurocutaneous disorder in which hamartomas confer significant medical risks, including mortality, by disruption of local tissues. However, only recently have multiple studies assessed specific aetiologies of mortality in TSC. Methods: A literature review of all available studies examining mortality in TSC was conducted until December 15, 2024. Results: We identified 13 studies reporting 411 deaths from 6735 individuals with TSC. Crude mortality per 100 individuals ranged from 1.4-13.8 over average intervals of 11-45 years. Mortality risk ranged from 3.0-4.9 (mean 4.3) versus the general population. Mean life expectancy was 66.2 years compared to 81.8 in the general population. In seven studies that reported specific aetiologies of mortality, 6/7 (85%) had renal (commonly renal failure or angiomyolipoma hemorrhage) or brain disease (most frequently sudden unexpected death in epilepsy or brain tumours) as the most common cause of mortality. Intellectual delay conferred increased mortality risk. Lymphangioleiomyomatosis conferred significant risk of mortality in adult women and cardiac rhabdomyomas were the dominant cause of neonatal mortality. Conclusions: Mortality in TSC is elevated compared to the general population, with brain and renal disease most frequently culpable. Future studies should assess the impact of disease modifying therapies on mortality in TSC.

Background: Inuit children have been observed to have high rates of macrocephaly, which leads to burdensome travel for medical evaluation, often with no pathology identified. Given reports that WHO growth charts may not reflect all populations, we compared head circumference (HC) measurements in a cohort of Inuit children with the WHO charts. Methods: We extracted HC data from a retrospective cohort study where, with Inuit partnership, we reviewed medical records of Inuit children, born between 2010-2013, and residing in Nunavut. We excluded children with preterm birth, documented neurologic/genetic disease, and most congenital anomalies. We compared HC values with the 2007 WHO charts. Results: We analyzed records of 1960 Inuit children (8866 data points). Most data were from ages 0-36 months. At all age points, the cohort had statistically significantly larger HC than WHO medians. At age 12 months, median HC were 1.3 cm and 1.5 cm larger for male and female Inuit children. Using WHO growth curves, macrocephaly was overdiagnosed and microcephaly underdiagnosed. Conclusions: Our results support the observation that Inuit children from Nunavut have larger HCs, and use of the WHO charts may lead to overdiagnosis of macrocephaly and underdiagnosis of microcephaly. Population specific growth curves for Inuit children should be considered.