Ajith J. Thomas

BACKGROUND AND IMPORTANCE: Ventriculoperitoneal (VP) shunt placement remains a standard treatment of hydrocephalus, yet the commonly used method of freehand proximal catheter placement is associated with high rates of malposition. Although stereotactic navigation increases accuracy, it can introduce workflow inefficiency and increase intraoperative complexity. Augmented reality (AR) is an emerging technology that provides real-time integration of 3-dimensional imaging directly onto the surgical field. This report aimed to describe the feasibility and technical nuances of AR-guided proximal catheter placement using the Novarad VisAR system during a VP shunt surgery. CLINICAL PRESENTATION: An eighty-one-year-old man with normal pressure hydrocephalus underwent elective VP shunt placement. CONCLUSION: Proximal catheter placement was successfully accomplished on first pass using AR guidance. Postoperative computed tomography head confirmed accurate placement consistent with preoperative planning. This case illustrates the first use of AR guidance for presurgical planning and intraoperative placement of a proximal ventricular catheter and demonstrates the feasibility of this technique.

Chronic subdural hematomas (cSDHs) have risen in incidence to ≈17 to 19 cases per 100 000 persons per year over the recent decade, especially in the elderly population, with an estimated incidence of up to 355 cases per 100 000 per year in those ≥85 years. cSDHs are projected to be the most common neurosurgical condition by 2030. Recurrence rates with current treatment approaches, such as surgical evacuation with burr hole craniostomy or craniotomy, are high. These treatments often do not address the underlying inflammatory process, which is a key driver in cSDH development and progression. cSDHs develop when trauma to the inner dural border cell layer leads to an inflammatory response promoting neoangiogenesis, the ingrowth of new fragile vessels that are highly prone to leakage. Subsequent rebleeding, exudation, and incomplete resorption exacerbate the inflammatory response, leading to a self-perpetuating process. This review provides an overview of the inflammatory mechanisms involved in cSDHs, highlighting key biomarkers and cellular pathways, as well as associated translational clinical implications. Expanding upon existing therapies, reexamining these pathways presents opportunities to identify future potential therapeutic targets.

Chronic subdural hematoma (CSDH) is an increasingly common disorder characterized by persistent accumulation of blood products and inflammatory exudate within the dural border cell (DBC) layer. Its pathogenesis represents a self-sustaining cycle of inflammation, pathological angiogenesis, and impaired resolution. Injury of the head, which may be traumatic or nontraumatic, initiates cleavage of the DBC layer, leading to fibroproliferative membrane formation mediated by collagen synthesis and TGF-β1/SMAD signaling. The resulting outer membrane develops fragile neovasculature, driven primarily by vascular endothelial growth factor, facilitating recurrent microhemorrhage and fibrinolysis perpetuating hematoma expansion. Chronic inflammation sustains disease progression through macrophage polarization, cytokine release, and increased vascular permeability, processes amplified by age-related immune dysregulation and hypoxia-induced factor-1alpha signaling. Impaired tissue repair due to metabolic deficits further limits resolution. Concurrent dysfunction of meningeal lymphatic drainage and fibrotic arachnoid granulations compromises clearance of blood degradation products and inflammatory mediators, while matrix remodeling and cerebrospinal fluid ingress contribute to hematoma persistence. This narrative review presents a pathophysiologic framework highlighting CSDH as a dynamic inflammatory-angiogenic disorder. Pharmacological strategies targeting inflammation, angiogenesis, fibrinolysis, hypoxia, and matrix remodeling hold potential as complements or alternatives to established treatments, including surgical drainage and middle meningeal artery embolization. As the burden of CSDH on healthcare systems rises, translational research and controlled clinical trials will be critical to developing mechanism-driven, multimodal management paradigms.

Programmable ventriculoperitoneal (VP) shunts are essential for managing hydrocephalus, yet their magnetic adjustment mechanisms are vulnerable to interference from magnetic resonance imaging (MRI) scanners. This study presents an enhanced mathematical framework to quantify and compare the susceptibility of programmable shunt valves to unintended actuation in a 3 Tesla (3T) MRI environment. The model compares the magnetic torque exerted by the MRI field (τ MRI ) to the valve's inherent mechanical resistive torque (τ Resist ). We introduce a dimensionless Susceptibility Index (SI) and a real-world correction coefficient (α) to account for stochastic effects like stiction, bridging theoretical predictions with clinical behavior. Using published in vitro data, we show that first-generation (non-locking) valves are highly susceptible (SI ≫ 1), with MRI-induced torques up to 125 times greater than resistive torque. In contrast, second-generation (locking) valves are robust (SI < 1) due to mechanical designs resilient to uniform magnetic torque. A probabilistic model links the likelihood of valve actuation to both SI and α, offering a quantitative basis for the superior MRI safety of modern valves. This framework also highlights the engineering challenges posed by ultra-high-field (7T) MRI systems, where even advanced locking mechanisms may fail.

BACKGROUND AND OBJECTIVES: A common neurosurgical procedure is the placement of an external ventricular drain (EVD), often as a time-sensitive treatment for hydrocephalus and/or increased intracranial pressure. The etiology ranges from traumatic brain injury to spontaneous intracranial hemorrhages, frequently causing change to ventricular anatomy, making them difficult targets. The goal of this study was to determine whether the use of image-guidance for bedside EVD placement improves accuracy and decreases number of passes with the same time-effectiveness. METHODS: Adult patients with bedside EVD placement for traumatic brain injury or spontaneous intracranial hemorrhages between October 2021 and December 2023 were retrospectively reviewed and dichotomized by electromagnetic image-guided or freehand EVDs. The primary outcome was the rate of suboptimal placement (defined by Kakarla score). The secondary outcomes were rates of multipass EVDs and procedural time. RESULTS: Of 44 patients included, median age was 59 years (IQR 44-66), and 59.1% were men. Median midline shift was different between image-guided (3.5 mm [IQR 1.5-6.3]) and freehand (0 mm [IQR 0-5]) EVDs (P = .0013). With image-guidance, 100% of cases were completed with one pass and optimally placed (Kakarla 1). With freehand placement, 73.5% of cases were completed with one pass, and 88.2% were optimally placed. Median procedural times were similar between image-guided (55 minutes [IQR 50-60]) and freehanded (60 minutes [IQR 48.8-89.3]) placement (P = .71). Attributable risk reduction for suboptimal placement with image guidance was 11.76%. For every 9 image-guided EVDs, 1 additional suboptimal EVD placement will be prevented (number needed to treat = 9). Attributable risk reduction for multiple passes with image guidance was 26.5%. For every 4 image-guided EVDs, 1 additional patient will avoid multiple passes for EVD placement (number needed to treat = 4). CONCLUSION: Image guidance in bedside EVD placement does not require more time in comparison with freehand EVD placement and is associated with fewer passes and higher accuracy.

Background: Lyn kinase is a member of the Src family of tyrosine kinases, primarily known for its role in regulating immune cell signaling. It can phosphorylate and modulate the activity of various proteins involved in immune responses, including Toll‐like receptor 4 ( TLR4) . TLR4 ‐mediated inflammatory pathways have been extensively studied; however, the sex‐specific interaction of TLR4 and Lyn in neuroinflammation after aneurysmal subarachnoid hemorrhage ( SAH ) has yet to be investigated. SAH occurs due to a ruptured aneurysm, and the consequences often lead to neuroinflammation and cognitive impairments. In our study, we investigated the sex‐specific involvement of Lyn kinase in regulating TLR4 signaling to understand the TLR4 ‐mediated inflammatory response after SAH . Methods: Cell‐specific Lyn knockout mice of both sexes were used for this study. Wild‐type and conditional knockout mouse brains were analyzed by multicolor flow cytometry, immunohistochemistry, and western blotting at postoperative day 7 following SAH surgery. An unbiased spatial transcriptomic analysis was performed with the frozen mouse brain tissues. A 3‐dimensional brain stroke model and cerebrospinal fluid samples of patients with SAH were also used for this study. Results: Our overall animal and patient data from flow cytometry, immunohistochemistry, western blot, cognitive function tests, and spatial transcriptomic data revealed that Lyn kinase is a sex‐specific regulator in inflammatory cytokine production, red blood cell phagocytosis, neuronal apoptosis, and cognitive function, as well as a negative regulator of TLR4 signaling pathways. Conclusions: Our results highlight sex‐specific modulation of Lyn kinase activity in TLR4 signaling after hemorrhagic stroke and indicate that successful treatment of neuroinflammation may require sex‐specific treatments.

Background: Chronic subdural hematoma (cSDH) has a rising incidence associated with an increasing burden of disability and mortality worldwide. Vascular endothelial growth factor plays an integral role in the inflammation and formation of subdural membranes responsible for the origin and propagation of cSDH. We report an early experience of intra‐arterial bevacizumab, a vascular endothelial growth factor receptor antagonist, to the middle meningeal artery of 12 hemispheres in 8 patients with cSDH. Methods: Eight patients with either unilateral or bilateral cSDH received intra‐arterial infusion of 2 mg/kg bevacizumab into the middle meningeal artery of each treated hemisphere. The primary outcome was hematoma recurrence or reaccumulation requiring surgical drainage or middle meningeal artery embolization within 3 months posttreatment. Results: Of 12 hemispheres treated, no treatment‐related complications were reported. Median duration of follow‐up was 5 months (interquartile range 3–7.5). By 3 months posttreatment, no patients experienced hematoma recurrence or reaccumulation. One patient required concurrent evacuation at the time of bevacizumab administration. There were no major strokes or mortality within 3 months. Four hemispheres (33.3%) demonstrated complete radiographic hematoma resolution by 3 months. All hemispheres achieved 50% reduction in hematoma size by 3 months. Conclusion: For all hemispheres treated, there was no hematoma recurrence or progression requiring surgical drainage or middle meningeal artery embolization within 3 months except 1 who required concurrent evacuation 24 hours after treatment. Our initial experience supports bevacizumab as a novel, potentially viable agent for cSDH treatment in select patients. Future studies in larger cohorts are necessary to confirm efficacy and safety and appropriate dosing.

Middle meningeal artery embolization (MMAE) is emerging as a safe and effective standalone intervention for non-acute subdural hematomas (NASHs); however, the risk of hematoma recurrence after MMAE in coagulopathic patients is unclear. To characterize the impact of coagulopathy on treatment outcomes, we analyzed a multi-institutional database of patients who underwent standalone MMAE as treatment for NASH. We classified 537 patients who underwent MMAE as a standalone intervention between 2019 and 2023 by coagulopathy status. Coagulopathy was defined as use of anticoagulation/antiplatelet agents or pre-operative thrombocytopenia (platelets p < 0.05). On matched multivariable analysis, patients with coagulopathy had an increased odds ratio (OR) of requiring surgical rescue (OR 3.95; 95% confidence interval [CI] 1.68–9.30; p < 0.01). Antiplatelet agent use (ticagrelor, prasugrel, or clopidogrel) was also predictive of surgical rescue (OR 4.38; 95% CI 1.51–12.72; p = 0.01), and patients with thrombocytopenia had significantly increased odds of in-hospital mortality (OR 5.16; 95% CI 2.38–11.20; p < 0.01). There were no differences in follow-up radiographic and other clinical outcomes in patients with and those without coagulopathy. Patients with coagulopathy undergoing standalone MMAE for treatment of NASH may have greater risk of requiring surgical rescue (particularly in patients using antiplatelet agents), and in-hospital mortality (in thrombocytopenic patients).