Citations

Abstract Objective. Modern stereotactic neurosurgery increasingly relies on bilateral and multi-trajectory workflows (e.g. deep brain stimulation (DBS), stereoelectroencephalography (sEEG)), which can exceed the reach and flexibility of conventional frame-based systems. Building on our skull-mounted Navinetics D1 platform, we present a stereotactic frame (Navinetics E1) intended to expand the reachable work envelope, enable independent bilateral targeting, and preserve mechanical accuracy and patient comfort. Approach. We designed the Navinetics E1 stereotactic frame using a center-of-arc architecture with five degrees of freedom per hemisphere ( X, Y, Z , Arc, Collar) and two operating modes: Double Arm (independent left/right arms for simultaneous bilateral targeting) and Single Arm (mechanically coupled arms). The system was designed in CAD and fabricated via carbon fiber-reinforced polylactic acid (PLA-CF) additive manufacturing. Collision-aware MATLAB simulations quantified work volume and admissible approach directions. Mechanical targeting accuracy was evaluated on a ground truth fixture (GTF) platform, with mixed-effects modeling to assess target- and trajectory-dependent effects. Operative feasibility was assessed through an intraoperative entry-point replication test relative to the D1 system. Main results. Compared to the D1, the E1 frame significantly expanded key geometric ranges, including, most notably, 0°–360° Collar rotation and posterior Y -axis reach, thereby increasing the work volume and trajectory range by factors of 3.39 and 8.42, respectively. Mean GTF targeting deviation was 0.78 ± 0.38 mm in Single Arm mode and 1.23 ± 0.36 mm (right) and 1.65 ± 0.47 mm (left) in Double Arm mode. Entry-point replication across 17 clinical cases achieved 76.5% success in overlapping the reference points, providing preliminary evidence of feasibility under real operative conditions. Significance. The E1 frame extends a compact skull-mounted platform to support broader stereotactic reach and trajectory while enabling independent bilateral workflows. These features may reduce intraoperative reconfiguration for complex DBS and sEEG cases. Future work will focus on increasing structural stiffness, improving angular readout/setting, and developing MRI-compatible implementations.

Objectives: Elevated intracranial pressure (ICP) remains a challenge and immediate danger in patients with acute brain injury. Current literature supports the use of a single hyperosmolar agent to reduce ICP. However, the efficacy and safety of overlapping hyperosmolar agents have not been evaluated. The objectives of this study are to analyze the ICP lowering effects and evaluate the safety profile of overlapping hyperosmolar therapy. Materials and Methods: This single-center, retrospective study included adults (≥18 y) admitted to the Neurosciences Intensive Care Unit between May 2018 and September 2024 with acute brain injury leading to intracranial hypertension refractory to a single hyperosmolar agent and an ICP monitor. They received overlapping doses of mannitol and hypertonic sodium approximately every 3 hours. We evaluated the impact of overlapping hyperosmolar therapy on ICP. Safety outcomes included acute kidney injury incidence, electrolyte disturbances, and volume status changes. Results: Forty-six patients were included in this study with a median (IQR) age of 46.5 (35.9, 62.4) years. Median (IQR) dose of mannitol was 40.1 (34.6, 50.0) g, while median (IQR) dose of hypertonic sodium was 120 (90, 125) mEq. About 86% of patients experienced a decrease in ICP after initiation of overlapping hyperosmolar therapy. Six acute kidney injuries occurred, and 7 patients experienced pulmonary edema. Median (IQR) peak sodium, chloride, and osmolar gap values were 149 (144, 155) mEq/L, 115 (111, 119) mEq/L, and 5.7 (0.7, 9.0) mOsm/kg. Conclusions: Overlapping hyperosmolar therapy may provide a transient ICP reduction without excessive adverse effects in patients with refractory ICP to a single hyperosmolar agent.

PURPOSE In large B-cell lymphoma (LBCL), use of high-dose methotrexate (HD-MTX) to prevent CNS relapse (so-called CNS prophylaxis) remains controversial. International guidelines continue to recommend HD-MTX in patients deemed ultra high risk (UHR) because of a lack of robust data specific to these subgroups. This study was designed to examine the impact of HD-MTX specifically in UHR patients. METHODS Data from two previous retrospective analyses were combined to produce a cohort of UHR patients (≥1 of the following criteria: CNS international prognostic index score 5-6; testicular, renal/adrenal, or breast involvement; ≥3 extranodal sites), treated with or without HD-MTX. The primary outcome was CNS relapse rate (isolated or concurrent with systemic relapse) measured from diagnosis with additional landmark analysis of all responding patients with no progression event at 6 months. RESULTS Analyses were performed on 1,923 patients meeting UHR criteria. No significant difference in 3-year CNS relapse rate was observed between no HD-MTX (n = 1,051) versus HD-MTX patients (n = 872), including in multivariable analyses adjusting for baseline characteristics (3-year rate, 9.3% v 8.1%; adjusted hazard ratio [HR], 1.13 [95% CI, 0.82 to 1.57]). Analyses restricted to isolated CNS relapse also confirmed no difference (5.9% v 5.7%; adjusted HR, 1.03 [95% CI, 0.69 to 1.53]). In the landmark analysis (no HD-MTX n = 782, HD-MTX n = 773), no difference in 3-year CNS relapse was observed (6.7% v 6.6%, adjusted HR, 0.95 [95% CI, 0.62 to 1.44]). CONCLUSION To our knowledge, this is the largest international comparative data set of patients with LBCL with UHR features showing no significant reduction in CNS relapse with HD-MTX in all UHR or in any individual subgroup. Despite inherent limitations of retrospective analyses, the data strongly support previous studies in suggesting HD-MTX prophylaxis has no meaningful benefit for most patients.

Abstract Background and aims Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by recurrent thunderclap headaches and reversible multifocal cerebral arterial narrowing. Although prognosis is generally favorable, a subset of patients develops cerebrovascular complications that may drive long-term disability; this study aims to identify factors associated with these complications. Methods We retrospectively reviewed 348 patients with probable or definite RCVS evaluated at Mayo Clinic between 2010-2023. Diagnostic criteria were adapted from RCVS2 and ICHD-3. The primary outcome was a composite of ischemic stroke, non-aneurysmal subarachnoid hemorrhage, and intracerebral hemorrhage; secondary outcome was poor functional status (modified Rankin Scale ≥2 within one year). Univariable and multivariable logistic regression identified predictors of these outcomes. Results Cerebrovascular complications occurred in 37.6% of patients and were the strongest determinant of poor functional outcome (aOR 5.05, 95% CI 2.04–12.51). On multivariable analysis, older age (aOR per year 1.02, 95% CI 1.00–1.04) and angiographically visible vasoconstriction (aOR 3.14, 95% CI 1.85–5.33) were independently associated with higher risk of cerebrovascular complications, whereas male sex (aOR 0.55, 95% CI 0.30–0.99), thunderclap headache at presentation (aOR 0.30, 95% CI 0.11–0.86), and sexual activity as a trigger (aOR 0.19, 95% CI 0.08–0.42) were associated with lower risk of these complications. Conclusions Cerebrovascular complications are common and strongly predict disability. Angiographic vasoconstriction and older age identify patients at higher risk, whereas thunderclap headache and sexual activity as a trigger mark a more benign phenotype. These findings may guide early risk stratification and help tailored monitoring strategies. Conflict of interest Name of author: nothing to disclose.

Abstract A short diagnosis-to-treatment interval independently predicts inferior outcomes in follicular lymphoma. Using international discovery and validation cohorts, we demonstrate its prognostic value beyond established prognostic indices, with implications for risk stratification, clinical trial design, and interpretation.

Abstract We evaluated outcomes by management type for patients with stage IA nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) in the Global NLPHL One Working Group retrospective database of 2243 patients with stages I to IV disease diagnosed from 1992 to 2021 at 38 international institutions. A total of 779 patients had stage IA disease with median age of 35 years (range, 3-89) and median follow-up of 6.1 years. The 6-year progression-free survival (PFS) and overall survival were 86.3% and 97.7%, respectively. Outcomes were analyzed for the 2 groups: complete resection and unresected disease. Patients with a complete resection and observation alone (n = 99) had a 6-year PFS of 65.5% vs 90.5% for those who received radiotherapy (RT) (n = 53). Patients with unresected disease (n = 627; 80.5%) had a 6-year PFS of 62.0% for rituximab alone (n = 31), 89.6% for RT alone (n = 325), 76.8% for ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) alone (n = 40), and 94.3% for ABVD plus RT (n = 130). A total of 127 patients relapsed (16.3%), of which 25 (19.7%) had transformation. Our analysis suggests the following: (1) RT improves the PFS in patients with completely resected disease; (2) rituximab or ABVD alone does not appear to achieve a durable response; and (3) chemotherapy was not observed to add additional PFS benefit when used in combination with RT. Thus, for stage IA NLPHL, RT alone is likely sufficient for definitive treatment.

Background Resuming anticoagulation in patients with mechanical heart valves after intracranial hemorrhage presents a clinical dilemma. The optimal timing must balance the risk of thromboembolism against hemorrhagic expansion. Prior studies have addressed this issue, but most were limited by small sample sizes. This systematic review and meta‐analysis aimed to determine the optimal timing for anticoagulation resumption in this population. Methods We conducted a systematic review and meta‐analysis using PubMed, Embase, Web of Science, and Scopus from database inception to August 23, 2024. The target population included adults with intracranial hemorrhage who required anticoagulation for mechanical heart valves. Results Thirteen studies involving 788 patients were included: 12 retrospective and 1 prospective observational study. While off anticoagulation, 32 patients developed ischemic stroke, with a pooled event rate of 5.23% (95% CI, 3.80–7.20%) and negligible heterogeneity ( I 2 = 0%). The pooled average time to stroke was 8.08 days (95% CI, 1.99–14.18). After anticoagulation resumption, 73 patients experienced hemorrhagic recurrence, corresponding to a pooled event rate of 10.95%, with nonsignificant heterogeneity ( I 2 = 40.4%). Conclusions Withholding anticoagulation for up to 7 days after intracranial hemorrhage in patients with mechanical heart valves appears relatively safe. Hemorrhagic recurrence after resumption was more common than ischemic stroke during interruption. However, the included studies were observational and carried serious or critical risk of bias. Prospective multicenter studies, and ideally randomized trials, are needed to provide more definitive evidence.

BACKGROUND AND OBJECTIVES: External ventricular drain (EVD) placement is the most commonly performed bedside emergent neurosurgical procedure. However, catheter misplacement occurs in approximately 25% of cases, potentially resulting in neurological injury or the need for repositioning, highlighting the need for safer and more accurate placement techniques. This review aims to (1) summarize technological innovations developed to enhance the accuracy and safety of bedside EVD placement, (2) evaluate their reported benefits and limitations, and (3) identify key barriers to their clinical implementation in critical care settings. METHODS: We conducted a systematic review of PubMed, Embase, and Scopus combining terms related to EVD placement and assistive technologies. All the studies evaluated EVD placement using simulations, phantoms, cadavers, and patient procedures conducted at the bedside and in the operating room. RESULTS: We identified 3898 records, and 76 studies met the inclusion criteria. Of these, 30 studies compared stereotactic systems, ultrasound guidance, frameless neuronavigation, and augmented or mixed reality technologies to the freehand technique. These studies consistently reported improved accuracy with advanced systems although complication rates and procedural times were variably reported. An additional 35 and 12 studies evaluated nonimmersive and immersive technologies, respectively, in noncomparative settings. Most of these demonstrated high first-pass success and mean tip deviations under 3 mm. Variability in the definitions of accuracy and procedural metrics limited data synthesis, but the overall findings suggest a promising trajectory for technology-assisted EVD placement. CONCLUSION: Assistive technologies for EVD placement show potential to improve accuracy and safety over the freehand technique. These early successes signal potential to improve bedside neurosurgical care. Realizing this promise will require future studies to standardize accuracy metrics, report time, and safety outcomes consistently and validate performance in real-world critical care settings.