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Digest

The Weekly Signal

Published February 28, 2026

Executive Summary

This week's digest highlights: Time-Dependent Impact of Mismatch Profiles on Outcomes Following Endovascular Thrombectomy for Large Ischemic Stroke. Systematic Cavernous Sinus Exploration Combined With Early Hormonal Assessment in Cushing Disease.

Owen briefs you on what matters in this week's digest.

Think chief-resident chalk talk: what matters, what changes practice, and where to spend your reading time.

Tumor / Skull Base

Low evidence

Why it matters

Guideline and evidence synthesis can standardize diagnostic workup and counseling for skull base tumor patients.

Teaching pearl

When applying this evidence, confirm the primary endpoint definition and follow-up time in the full text before changing practice.

More context

High-yield

Journal article (design NR), N=37; resection extent and recurrence; neurological morbidity.

Functional

Hippocampal abnormality and response to vagus nerve stimulation in epilepsy.

Research • Functional • Epilepsia • 2025-10-03

Low evidence

Why it matters

Functional neurosurgery and epilepsy surgery evidence can inform patient selection and counseling about cognitive outcomes.

Teaching pearl

When applying this evidence, confirm the primary endpoint definition and follow-up time in the full text before changing practice.

More context

High-yield

Journal article (design NR), N=42; seizure freedom or symptom control; cognitive and functional side effects.

In epilepsy surgery planning, prioritize preservation of identified memory hubs (e.g., hippocampus, amygdala) showing high theta connectivity during encoding to reduce risk of postoperative memory decline.

OWhen planning epilepsy surgery, prioritize preserving memory hubs like the hippocampus and amygdala that show high theta connectivity during encoding to mitigate postoperative memory decline.

Low evidencePractice changing

Study snapshot

Design

Cohort study

Population

Adults with drug-resistant epilepsy undergoing presurgical stereo-EEG monitoring

Intervention

None (observational analysis of memory encoding connectivity)

Comparator

None

Primary outcome

Identification of brain regions with differential connectivity between remembered and forgotten words

Why it matters

We previously understood that memory encoding involves hippocampal and medial temporal lobe networks, but the specific network hubs and their connectivity patterns in the epileptic brain remained unclear. This study adds a data-driven identification of critical connectivity hubs (like the hippocampus and amygdala) that show differential theta/gamma synchronization during successful encoding, suggesting these regions coordinate large-scale memory networks. Clinicians should consider these network hubs as potential targets for preservation during epilepsy surgery planning to mitigate postoperative memory decline.

Practice change

May support considering network hub connectivity patterns during presurgical planning to preserve memory function.

More context

Key details

  • 15 adult patients with drug-resistant epilepsy undergoing stereo-EEG monitoring
  • Free recall task with 12 words per trial; analyzed connectivity during encoding phase
  • Identified hubs (e.g., hippocampus, amygdala) showing differential connectivity for remembered vs. forgotten words
  • Successful encoding associated with increased theta synchronization and decreased gamma connectivity in hubs
  • Connectivity metrics included coherence, phase synchrony, and relative entropy across frequency bands
  • Excluded channels in seizure onset zone from analysis
  • Aimed to inform presurgical planning to preserve memory networks

High-yield

Successful memory encoding in epilepsy patients relies on a sparse set of critical hubs—particularly the hippocampus and amygdala—that show increased theta synchronization and decreased gamma connectivity during word recall.

Clinical context

Cognitive impairments are common in drug-resistant epilepsy, and temporal lobe resections carry risk of memory decline. Epilepsy is recognized as a network disorder.

Limitations

Small cohort (n=15) limits generalizability and statistical powerObservational design without intervention prevents causal conclusions about hub preservation

Methodological critique

Small sample size and lack of control group limit robustness of connectivity findings.

Teaching pearl

When reviewing SEEG data for epilepsy surgery, look beyond the seizure onset zone—map theta-gamma connectivity in hubs like the hippocampus and amygdala during memory tasks to identify networks worth sparing.

Funding and COI

Not stated

General Neurosurgery

Implement these evidence-based algorithms for penetrating TBI management, particularly for angiography decisions and mortality prediction using the SPIN score.

OUse the SPIN score early for mortality prediction in penetrating TBI, but remember it's derived from military data and may overestimate mortality in civilian low-velocity injuries.

High evidencePractice changing

Study snapshot

Design

Practice guideline development with systematic literature review and expert consensus

Population

Patients with penetrating, perforating, and tangential penetrating traumatic brain injuries

Intervention

Evidence-based clinical care guidelines and algorithms

Comparator

None (guideline development)

Primary outcome

Development of clinical care recommendations for 26 key questions

Why it matters

Before this guideline, there were no up-to-date evidence-based recommendations for managing penetrating traumatic brain injury (pTBI), leaving clinicians to rely on outdated or anecdotal approaches. This second edition provides the first comprehensive, evidence-based framework for pTBI care across prehospital, emergency, surgical, and intensive care settings, synthesizing 125 studies and expert consensus. Clinicians should now use these guidelines to standardize management, particularly for cerebral angiography vs CTA, bihemispheric injury mortality prediction, SPIN score application, and infection/CSF fistula relationships.

Practice change

May support standardized management of penetrating TBI using evidence-based algorithms across care settings.

More context

Key details

  • Guidelines address 26 key questions across prehospital, emergency, surgical, and intensive care settings
  • Literature search covered Ovid MEDLINE®, EMBASE, and Cochrane CENTRAL from inception to August 31, 2022
  • Included penetrating, perforating, and tangential penetrating brain injuries
  • Over half of panelists were active service military or military veterans

High-yield

NR

Clinical context

Penetrating traumatic brain injury affects civilian and military populations with significant morbidity, mortality, and healthcare costs. No up-to-date evidence-based guidelines existed for modern medical and surgical management of these complex injuries.

Limitations

Paucity of literature with most evidence judged high risk of bias due to study design limitationsNo studies meeting inclusion criteria for nearly half (12 of 26) of the key questions addressed

Methodological critique

Guideline development was systematic but limited by the paucity of high-quality evidence, with most studies being case series at high risk of bias.

Teaching pearl

When managing penetrating TBI, remember that the SPIN score has moderate evidence for mortality prediction—calculate it early to guide prognosis discussions and resource allocation, especially in military or high-velocity injury contexts.

Funding and COI

Not stated

Basic Science

KMT2A is a prerequisite of malignant transformation during IDH-mutant gliomagenesis.

Research • Basic Science • Neuro-oncology • 2026-01-14

Low evidence

Why it matters

Mechanistic work may identify targets that later translate into neurosurgical oncology or neuroregeneration therapies.

Teaching pearl

When applying this evidence, confirm the primary endpoint definition and follow-up time in the full text before changing practice.

More context

High-yield

Basic science (preclinical); mechanistic endpoints in methods; not applicable (preclinical).

P2X7R-mediated IL-1β release by human brain tissue: the impact of CNS-penetrant potential therapeutics.

Research • Basic Science • Brain : a journal of neurology • 2026-02-19

NR

Low evidencePractice changing

Study snapshot

Design

Basic science preclinical study

Population

Human monocyte-derived microglia and brain tissue slices

Intervention

P2X7 receptor antagonists

Comparator

None

Primary outcome

IL-1β release suppression

Why it matters

We previously had animal model data showing P2X7 receptor drives neuroinflammation in TBI, but human translational evidence was lacking. This study adds that P2X7 antagonists suppress IL-1β release in human microglia and brain tissue, confirming the receptor's role in human neuroinflammation. Clinicians should monitor development of brain-penetrant P2X7 antagonists as they may offer a new therapeutic avenue for TBI and other neuroinflammatory conditions.

Practice change

Confirms current practice of monitoring neuroinflammation but does not yet change clinical management.

More context

High-yield

NR

Clinical context

Traumatic brain injury lacks approved drugs, and neuroinflammation provides a therapeutic window. P2X7 receptor is a key driver in animal models.

Limitations

Ex vivo/in vitro models may not fully replicate in vivo neuroinflammatory complexityNo patient outcomes data; purely mechanistic study

Methodological critique

Lack of in vivo validation limits direct clinical applicability.

Teaching pearl

When a TBI patient hits the ICU, remember: the P2X7 receptor on microglia is a key inflammation driver—future brain-penetrant antagonists could be a game-changer, so stay updated on clinical trials.

Funding and COI

Not stated

From the Preprint Wire

Neural Dynamics Model Explains Heterogeneity in DBS Gamma Responses

Preprint • From the Preprint Wire • medrxiv • 2026-02-14

Why it matters

This preprint offers a theoretical framework that could help explain why deep brain stimulation (DBS) produces variable gamma oscillation responses across Parkinson's disease patients, potentially informing more personalized stimulation strategies. As an unreviewed preprint, it provides intriguing mechanistic insights but requires validation before clinical application.

More context

Key details

  • The Wilson-Cowan model shows that off-stimulation oscillation characteristics (strongly damped, weakly damped, or self-sustained) predict different DBS response patterns.
  • Hysteresis effects were observed where half-harmonic responses appear and disappear at different stimulation amplitude thresholds, complicating adaptive control.
  • The framework suggests that patient-specific neural dynamics could guide DBS parameter optimization to better promote physiological rhythms and suppress pathological ones.

Undiagnosed Autoimmune Encephalitis in Swedish Memory Clinic Patients

Preprint • From the Preprint Wire • medrxiv • 2026-02-14

Why it matters

This preprint suggests that 0.8% of patients attending Swedish memory clinics for suspected neurodegenerative dementia may have undiagnosed autoimmune encephalitis (AE), a treatable condition often misdiagnosed as dementia. For neurosurgeons, this highlights the importance of considering AE in differential diagnoses for cognitive impairment, especially since early treatment can prevent irreversible neurological damage. However, as this is an unreviewed preprint, the findings require validation before influencing clinical practice.

More context

Key details

  • Screened sera from 1,041 patients at Karolinska University Hospital memory clinics (2019-2023) for autoantibodies to CASPR2, LGI1, GABABR, NMDA-R, and IgLON5 using live cell-based assays.