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Digest

The Weekly Signal

Published April 19, 2026

Executive Summary

This week's digest highlights: Systolic blood pressure within 24 hours post-reperfusion is a significant predictor of outcomes in acute ischemic stroke, emphasizing the need for careful monitoring. Supramarginal resection for glioblastoma may offer improved survival compared to gross total resection alone, warranting consideration when feasible. Preoperative assessments for lumbar spinal stenosis surgery should...

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

Consider supramarginal resection for glioblastoma when safely achievable, as it may improve survival compared to gross total resection alone.

OConsider supramarginal resection for glioblastoma when feasible, as it may enhance survival compared to gross total resection, but be cautious of the heterogeneous nature of the supporting evidence and the potential functional risks involved.

High evidencePractice changing

Study snapshot

Design

Systematic review and meta-analysis of observational studies

Population

Patients with glioblastoma multiforme

Intervention

Supramarginal/supratotal resection (beyond contrast-enhancing margins)

Comparator

Gross total resection (complete removal of contrast-enhancing tumor)

Primary outcome

Overall survival

Why it matters

While gross total resection is standard for glioblastoma, the benefit of extending resection beyond contrast-enhancing margins (supramarginal resection) has been debated. This meta-analysis found supramarginal resection was associated with improved overall survival compared to gross total resection. Surgeons could consider supramarginal resection when safely achievable, particularly in non-eloquent areas.

Practice change

Could consider supramarginal resection when safely achievable, particularly in non-eloquent areas.

More context

Key details

  • Systematic review and meta-analysis of 12 cohort studies

High-yield

See source article for primary outcome data.

Clinical context

The extent of resection plays a significant role in glioblastoma prognosis. Supramarginal resection extends beyond tumor margins to include adjacent infiltrated tissue.

Limitations

High heterogeneity (I²=96%) limits confidence in pooled estimatesObservational studies only - no randomized trials included

Methodological critique

Study design details require full-text review for critical appraisal.

Teaching pearl

When planning GBM resection, remember that going beyond the contrast-enhancing margin (when safe) may improve survival - but this evidence comes from heterogeneous observational data, so balance potential benefits against functional risks.

Funding and COI

Not stated

Spine

Consider symptom duration, psychological distress, and disc degeneration in preoperative assessments for LSS surgery.

OIn preoperative assessments for lumbar spinal stenosis surgery, prioritize evaluating symptom duration, psychological distress, and disc degeneration, as patients with pain lasting over 12 months are at a significantly increased risk for unsatisfactory outcomes.

High evidencePractice changing

Study snapshot

Design

Secondary analysis of randomized trial data

Population

Patients with lumbar spinal stenosis undergoing surgical treatment

Intervention

Surgical treatment for lumbar spinal stenosis

Comparator

None (single-arm analysis of surgical outcomes)

Primary outcome

Unsuccessful outcome defined as <30% improvement in Oswestry Disability Index at 2 years

Why it matters

Approximately 30% of patients report unsatisfactory outcomes after lumbar spinal stenosis surgery, but predictors have been inconsistent. This secondary analysis identified three independent predictors of unsuccessful outcomes: pain duration >12 months, psychological distress, and advanced disc degeneration. Clinicians should incorporate these factors into preoperative counseling and patient selection.

Practice change

May support incorporating assessment of symptom duration, psychological status, and disc degeneration into preoperative counseling and patient selection.

More context

Key details

  • Secondary analysis of two randomized NORDSTEN trials
  • Unsuccessful outcome defined as <30% improvement in Oswestry Disability Index at 2 years
  • Multivariable logistic regression analysis used
  • Age, BMI, smoking, ASA grade, and predominant back pain were not significant predictors
  • Patients with and without degenerative spondylolisthesis included in original trials

High-yield

See source article for primary outcome data.

Clinical context

Nearly one-third of patients report unsatisfactory outcomes after lumbar spinal stenosis surgery. Identifying predictors is essential for improving patient selection.

Limitations

Secondary analysis of trial data not originally designed for predictor identificationLimited to patients enrolled in surgical trials who may differ from general population

Methodological critique

Secondary analysis of trial data not originally designed for predictor identification.

Teaching pearl

When evaluating LSS surgery candidates, pay particular attention to symptom duration - patients with pain >12 months have substantially higher risk of poor outcomes, and this should factor heavily into shared decision-making.

Funding and COI

Not stated

Functional

Deep Brain Stimulation for Disorders of Consciousness: An Individual Patient Data Meta-Analysis.

Research • Functional • Neuromodulation : journal of the International Neuromodulation Society • 2026-01-16

DBS for disorders of consciousness should be considered experimental with modest benefits and substantial risks, requiring careful patient selection.

ODBS for disorders of consciousness may yield modest benefits in a select group of younger patients with shorter durations of impaired consciousness, but clinicians must approach this intervention with caution due to substantial risks and the experimental nature of the treatment.

High evidencePractice changing

Study snapshot

Design

Individual patient data meta-analysis

Population

Patients with disorders of consciousness who underwent DBS

Intervention

Deep brain stimulation

Comparator

None (single-arm meta-analysis)

Primary outcome

Coma Recovery Scale-Revised (CRS-R) improvement

Why it matters

DBS has been proposed as a potential treatment for disorders of consciousness, but evidence has been limited to small, heterogeneous studies. This meta-analysis provides pooled data showing DBS confers modest improvements in conscious awareness, with only about 39.5% of patients achieving clinically meaningful improvement and 30.9% transitioning to a higher consciousness category. Clinicians should view DBS for DoC as an experimental intervention with limited benefits and substantial risks, requiring rigorous patient selection and standardized protocols.

Practice change

Confirms current practice that DBS for disorders of consciousness remains experimental with limited benefits.

More context

Key details

  • Individual patient data meta-analysis of 9 studies comprising 81 patients with disorders of consciousness
  • Primary outcome was Coma Recovery Scale-Revised (CRS-R) improvement
  • Pooled mean CRS-R improvement was 2.15 points
  • Younger patients with shorter DoC durations tended to show greater improvements
  • Considerable heterogeneity across studies (I² = 76.5%)
  • Adverse effects including infections and seizures were reported
  • Etiology was largely nonpredictive, though hypoxic-ischemic encephalopathy patients showed marginally better responses

High-yield

DBS for disorders of consciousness shows modest benefit with only 39.5% of patients achieving clinically meaningful improvement and 30.9% transitioning to a higher consciousness category.

Clinical context

DBS has been proposed as a promising therapeutic intervention for patients with disorders of consciousness.

Limitations

Considerable heterogeneity across included studies (I² = 76.5%) limits generalizabilityLimited sample size of 81 patients across 9 studies restricts statistical power

Methodological critique

Considerable heterogeneity limits generalizability.

Teaching pearl

When considering DBS for disorders of consciousness, focus on younger patients with shorter duration of impaired consciousness, as they show the greatest potential for meaningful improvement.

Funding and COI

Not stated

General Neurosurgery

Consider refined temporal-to-frontal horn shunting as an effective alternative to ventriculoperitoneal shunting for trapped temporal horn syndrome.

ORefined temporal-to-frontal horn shunting may offer a promising alternative to ventriculoperitoneal shunting for trapped temporal horn syndrome, but further studies are needed to solidify its long-term efficacy and safety profile.

Moderate evidencePractice changing

Study snapshot

Design

Retrospective multicenter case series

Population

53 consecutive patients with imaging-confirmed trapped temporal horn syndrome after brain tumor surgery

Intervention

Refined temporal-to-frontal horn shunting

Comparator

None (single-arm series)

Primary outcome

Symptom improvement and temporal horn volume reduction

Why it matters

Trapped temporal horn syndrome is a challenging complication after intraventricular tumor resection with limited evidence for optimal management. This study demonstrates that refined temporal-to-frontal horn shunting achieves high success rates with substantial temporal horn volume reduction. Surgeons could consider RTFHS as a valuable alternative to ventriculoperitoneal shunting for selected patients with TTH.

Practice change

Could consider refined temporal-to-frontal horn shunting as a valuable alternative to ventriculoperitoneal shunt in selected patients with trapped temporal horn syndrome.

More context

Key details

  • Retrospective case series of 53 consecutive patients with imaging-confirmed trapped temporal horn syndrome
  • Patients treated at two centers between January 2018 and January 2025
  • All patients underwent refined temporal-to-frontal horn shunting
  • Follow-up ranged from 1 month to 6 years
  • Volume reduction showed rapid decrease in 1st week, slower decline from 1 week to 3 months, then stabilization
  • Long-term follow-up showed no recurrence or re-enlargement in most patients
  • Complications were effectively managed in nearly all cases

High-yield

See source article for primary outcome data.

Clinical context

Trapped temporal horn syndrome is a rare form of obstructive hydrocephalus that frequently occurs after intraventricular tumor resection. Effective long-term management remains challenging.

Limitations

Retrospective design without control group limits causal inferenceVariable follow-up duration (1 month to 6 years) with only 28 patients followed over 6 months

Methodological critique

Retrospective design without control group limits causal inference.

Teaching pearl

When placing a temporal-to-frontal horn shunt, expect the greatest volume reduction in the first week, with continued improvement through 3 months before stabilization.

Funding and COI

Not stated

Basic Science

Preclinical evidence; no immediate practice change pending clinical validation.

Low evidence

Why it matters

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

High-yield

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

Trials to Know

Why it matters

This trial evaluates Histoacryl® embolization of the middle meningeal artery (MMA) for chronic subdural hematoma (CSDH), a common neurosurgical condition often requiring surgical evacuation. It addresses the need for minimally invasive alternatives to reduce recurrence rates and procedural morbidity, potentially offering a less invasive option for high-risk or recurrent CSDH patients. If effective, this could shift practice toward endovascular management as a first-line or adjunctive treatment.

FET-PET/MRI Fusion for Glioblastoma Treatment Planning

Trial • Trials to Know • ClinicalTrials.gov • 2026-04-19

Why it matters

This trial evaluates FET-PET fused with MRI for glioblastoma treatment planning, addressing the critical need for more precise tumor delineation beyond standard MRI. For neurosurgeons, this could enhance surgical targeting and potentially improve resection margins by better identifying metabolically active tumor regions, which may impact adjuvant therapy decisions and patient outcomes.

Sevoflurane vs. Desflurane Effects on Optic Nerve Sheath Diameter in Laparoscopic Surgery

Trial • Trials to Know • ClinicalTrials.gov • 2026-04-19

Why it matters

This trial directly addresses how anesthetic choices during laparoscopic surgery affect intracranial pressure (ICP), as measured by optic nerve sheath diameter (ONSD), which is critical for neurosurgical patients at risk of secondary brain injury. It compares sevoflurane and desflurane to determine which better mitigates ICP elevation during pneumoperitoneum, filling a gap in evidence on optimizing perioperative management for neurosurgical cases involving abdominal procedures. The findings could inform anesthetic protocols to reduce neurological complications in vulnerable populations.

From the Preprint Wire

OSA Linked to Peri-Lead Edema After DBS for Parkinson's Disease

Preprint • From the Preprint Wire • medrxiv • 2026-04-06

Why it matters

This preprint identifies obstructive sleep apnea (OSA) as a potential risk factor for symptomatic peri-lead edema (PLE) following deep brain stimulation (DBS) surgery, a complication affecting up to 15% of cases that can lead to neurological deficits and prolonged hospitalization. If validated, this could prompt neurosurgeons to incorporate preoperative sleep evaluations and optimize perioperative oxygenation strategies to mitigate PLE risk. However, as an unreviewed preprint, these findings require confirmation through peer review and prospective studies before clinical implementation.

More context

Key details

  • PLE occurred in 9.9% of 121 PD patients undergoing DBS, with onset typically around 3.5 days postoperatively.
  • PLE severity correlated with sleep-related hypoxemia indices, and RBDSQ scores were positively associated with edema density (rho=0.86, p=0.024).
  • REM sleep behavior disorder (RBD) incidence was lower in PLE patients (20% vs. 60%), suggesting a potential protective effect against edema formation.

Theta-Range SEEG Stimulation for Temporal Lobe Mapping

Preprint • From the Preprint Wire • medrxiv • 2026-04-05

Why it matters

This preprint explores theta-range (7 Hz) electrical brain stimulation during SEEG for epilepsy surgery, which could enhance functional mapping and epileptic network identification in the temporal lobe. As an unreviewed study, it suggests that varying stimulation frequencies beyond conventional 1-Hz and 50-Hz protocols might reduce false positives/negatives, potentially improving surgical outcomes, but requires cautious interpretation pending peer validation.

More context

Key details

  • Analyzed 1,408 temporal EBS in 25 drug-resistant epilepsy patients, comparing 7-Hz, 1-Hz, and 50-Hz protocols across structures like amygdala and hippocampus.
  • 7-Hz stimulation showed higher afterdischarges and clinical signs than 1-Hz in some temporal areas (e.g., parahippocampal epileptogenic zone, p=0.014), but seizure induction effects were inconsistent.
  • No adverse events reported, suggesting safety, but results highlight the need for broader frequency exploration rather than reliance on standard protocols.

Conferences & Courses

AANS Annual Scientific Meeting 2026

Conference • Conferences & Courses • Event page • 2026-04-19

Why it matters

The 2026 meeting continues the AANS tradition of bringing together neurosurgeons for scientific exchange and education.