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Digest

The Weekly Signal

Published March 27, 2026

Executive Summary

This week's digest highlights: Flow diversion is a safe and effective treatment for selected distal cerebral aneurysms, especially in the anterior cerebral artery territory. In managing multiple pituitary adenomas, evaluate all lesions with endocrine correlation to avoid diagnostic pitfalls and enhance surgical strategies. Assessing self-image is crucial in adult spinal deformity patients, as it significantly...

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.

Endovascular / Vascular

Flow diversion for distal cerebral aneurysms: a systematic review and meta-analysis.

Research • Endovascular / Vascular • Journal of neurointerventional surgery • 2026-03-13

Flow diversion appears to be a safe and effective option for carefully selected distal cerebral aneurysms, particularly in the anterior cerebral artery territory.

OFlow diversion can be a safe and effective treatment for selected distal cerebral aneurysms, especially in the anterior cerebral artery territory, but clinicians should remain cautious of the 5.5% risk of covered branch occlusion.

High evidencePractice changing

Study snapshot

Design

Systematic review and meta-analysis

Population

Patients with distal cerebral aneurysms (located at or beyond ACA A2, MCA M2, and PCA P2 segments)

Intervention

Flow diverter treatment

Comparator

None (single-arm synthesis)

Primary outcome

Adequate and complete aneurysm occlusion, procedure-related morbidity and mortality

Why it matters

Flow diverters are increasingly used off-label for distal cerebral aneurysms, but comprehensive safety and efficacy data have been limited. This meta-analysis synthesizes current evidence, showing high occlusion rates and low complication rates for this application. Clinicians could consider flow diversion as a viable option for carefully selected distal cerebral aneurysms, particularly in the anterior cerebral artery territory.

Practice change

Could consider flow diversion as a viable option for carefully selected distal cerebral aneurysms, particularly in the anterior cerebral artery territory.

More context

Key details

  • Systematic review and meta-analysis of 18 studies with 441 patients (70% women)
  • 445 distal cerebral aneurysms, mostly unruptured (93.7%) and in ACA territory (78.4%)
  • Retreatment rate was 1.6% (95% CI, 0.2 to 3)

High-yield

Flow diversion for distal cerebral aneurysms achieved adequate occlusion in and complete occlusion in of cases, with procedure-related morbidity of 1.5% and mortality of .

Clinical context

Flow diverters are increasingly used off-label for distal cerebral aneurysms, but data on their safety and efficacy remain limited. This systematic review and meta-analysis synthesizes current evidence on FD treatment for DCAs.

Limitations

Included studies were observational with potential selection biasLimited long-term follow-up data on durability and delayed complications

Methodological critique

Limited to observational studies with potential selection bias.

Teaching pearl

When considering flow diversion for distal aneurysms, remember that ACA territory lesions dominate the literature and show promising results, but be particularly vigilant for covered branch occlusion which occurred in about 5.5% of cases.

Funding and COI

Not stated

Tumor / Skull Base

In multiple pituitary adenomas with functioning components, systematically evaluate all lesions with endocrine correlation rather than focusing solely on the most radiologically prominent mass.

OIn cases of multiple pituitary adenomas, prioritize a thorough evaluation of all lesions for endocrine activity, as the true source of hormonal excess may be smaller and less prominent than the dominant radiological mass, which could lead to missed diagnoses and suboptimal surgical outcomes.

High evidencePractice changing

Study snapshot

Design

Systematic review

Population

Patients with multiple pituitary adenomas, particularly those with functioning components

Intervention

Surgical identification and treatment strategy

Comparator

None (descriptive review)

Primary outcome

Identification of responsibility versus decoy lesions and surgical outcomes

Why it matters

Multiple pituitary adenomas with functioning components present diagnostic challenges when radiologically dominant lesions don't correspond to hormonally active ones. This review identifies that responsibility lesions are often less conspicuous on MRI and smaller than decoy lesions. Surgeons should systematically evaluate all lesions in multiple pituitary adenoma cases, not just the most radiologically prominent ones, to avoid missing the true source of hormonal excess.

Practice change

Surgeons should systematically evaluate all lesions in multiple pituitary adenoma cases with endocrine correlation, not just the most radiologically prominent ones.

More context

Key details

  • Systematic review of English-language case reports (2000-2024) plus 2 illustrative cases
  • 35 patients included in the review
  • Lesions classified as responsibility or decoy based on endocrine outcomes, radiology, and surgical findings
  • Responsibility lesions are less conspicuous on preoperative MRI and usually smaller than decoy lesions
  • Missed identification of responsibility lesion reported in substantial proportion of cases
  • Focus on diagnostic pitfalls and surgical strategies for multiple pituitary adenomas

High-yield

In multiple pituitary adenomas with functioning components, 43% of patients failed to achieve biochemical remission after initial surgery, often due to missed identification of the true responsibility lesion.

Clinical context

Multiple pituitary adenomas, particularly those involving functioning adenoma, represent a special subtype that pose dual challenges in diagnosis and treatment. The coexistence of hormonally active and silent lesions may result in diagnostic pitfalls.

Limitations

Based on case reports with inherent publication biasSmall sample size limits generalizability

Methodological critique

Based on case reports with publication bias.

Teaching pearl

In multiple pituitary adenoma cases, don't let the biggest MRI lesion distract you - the hormonally active lesion is often smaller and less conspicuous, so systematically evaluate all lesions with endocrine correlation.

Funding and COI

Not stated

Spine

Formally assess self-image when counseling adult spinal deformity patients, as it strongly influences both surgical decision-making and postoperative satisfaction.

OClinicians should incorporate formal assessments of self-image into the counseling process for adult spinal deformity patients, as it significantly influences surgical decision-making and postoperative satisfaction, despite the moderate evidence quality.

Moderate evidencePractice changing

Study snapshot

Design

Prospective, multicenter analysis

Population

Adult spinal deformity patients

Intervention

Operative versus nonoperative treatment

Comparator

Nonoperative treatment

Primary outcome

Factors correlating with treatment choice and treatment satisfaction

Why it matters

Adult spinal deformity outcomes have traditionally focused on pain and physical function, with limited data on self-image's role in treatment decisions and satisfaction. This study demonstrates that self-image is the strongest predictor of patients choosing surgery and correlates most with postoperative satisfaction. Clinicians should formally assess self-image when counseling ASD patients, as it significantly influences both treatment choice and ultimate satisfaction.

Practice change

May support formally assessing self-image when counseling adult spinal deformity patients, as it strongly influences both surgical decision-making and postoperative satisfaction.

More context

Key details

  • Prospective, multicenter analysis of ASD patients (2009-2020)
  • Minimum 2-year follow-up for treatment satisfaction assessment
  • Operatively treated patients had worse baseline PROMs than nonoperatively treated (p<0.0001)
  • Gradient-boosted decision trees, factor analysis, and logistic regression used
  • Nonoperative patients demonstrated deterioration of self-image and reported poor treatment satisfaction
  • Self-image improvement correlated most with post-treatment satisfaction in operative group
  • Data from physical exam, demographics, spinal alignment, and PROMs (SRS-22r, ODI, SF36, NRS)

High-yield

Self-image had the greatest correlation with patients choosing operative treatment (odds ratio=) and demonstrated the greatest health domain improvement postoperatively, correlating most with treatment satisfaction.

Clinical context

ASD outcomes traditionally focus upon pain and physical function. Self-image is an important outcome measure for pediatric spine deformity. Little data exists regarding the impact self-image has upon ASD treatment choice and outcomes.

Limitations

Observational design limits causal inferencePotential selection bias in treatment assignment

Methodological critique

Observational design limits causal inference about treatment effects.

Teaching pearl

When counseling ASD patients, ask specifically about self-image concerns - it's not just about pain and function, but how patients see themselves that most strongly predicts who will choose surgery and be satisfied afterward.

Funding and COI

Not stated

Functional

Fusion of Supervised Feature Selection and Unsupervised Clustering for Multinuclei Classification of MER Signals in DBS for Parkinson's Disease.

Research • Functional • IEEE transactions on neural networks and learning systems • 2026-03-27

Consider incorporating this hybrid machine learning framework as an adjunct tool to improve efficiency and accuracy when identifying STN, Zi, and SN during DBS electrode placement.

OWhile the hybrid machine learning framework shows promise in improving intraoperative identification of key nuclei during DBS for Parkinson's disease, its low evidence quality necessitates cautious integration into clinical practice until further validation is achieved.

Low evidencePractice changing

Study snapshot

Design

Journal article (design not specified)

Population

Not specified in source

Intervention

Three-class classification strategy for MER signals integrating supervised feature selection with unsupervised clustering

Comparator

Expert labeling

Primary outcome

Classification accuracy for distinguishing zona incerta, STN, and substantia nigra

Why it matters

Accurate intraoperative identification of key nuclei during DBS surgery for Parkinson's disease has traditionally relied on expert annotations and binary classification, limiting real-time recognition of complex neuroanatomy. This study introduces a hybrid supervised-unsupervised approach that achieves high classification accuracy for three nuclei while substantially reducing manual annotation burden. Neurosurgeons could consider this computational framework as a potential tool to enhance intraoperative targeting efficiency during DBS procedures.

Practice change

Could consider as an adjunct computational tool to enhance intraoperative targeting efficiency during DBS procedures.

More context

Key details

  • Proposes three-class classification of MER signals to distinguish zona incerta, STN, and substantia nigra
  • Integrates random forest algorithm for feature selection with fuzzy c-means clustering for preliminary classification
  • Low-confidence samples undergo manual review, creating an efficient label-generation mechanism
  • Overall classification accuracy of 92.71% closely matches expert labeling accuracy
  • Method reduces manual annotation costs while maintaining high accuracy
  • Well-suited for real-time applications like intraoperative target localization
  • Shows strong potential for clinical translation in DBS procedures

High-yield

A hybrid machine learning approach combining supervised feature selection with unsupervised clustering achieved 92.71% accuracy in classifying three key nuclei from MER signals during DBS surgery, with only about 10% of samples requiring manual verification.

Clinical context

Accurate intraoperative identification of key nuclei is critical for DBS efficacy in Parkinson's disease. Current approaches depend on expert annotations and are typically limited to binary classification.

Limitations

Study design not clearly specified in source material, limiting assessment of methodological rigorNo information provided about sample size, patient demographics, or validation cohort characteristics

Methodological critique

Study design not clearly specified, limiting assessment of methodological rigor.

Teaching pearl

When reviewing MER signals during DBS, remember that computational approaches can now distinguish between three key nuclei with high accuracy, potentially reducing the cognitive load on the surgeon during real-time targeting.

Funding and COI

Not stated

General Neurosurgery

Comparative analysis of analgesic mechanisms in craniotomy pediatric patients: a scoping review.

Research • General Neurosurgery • Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery • 2026-03-23

Implement multimodal analgesic regimens for pediatric craniotomy patients, combining opioids with non-opioid agents while carefully monitoring for neurological side effects.

OIn pediatric craniotomy patients, employing a multimodal analgesic strategy that combines opioids with non-opioid agents is advisable, but clinicians must remain vigilant for potential neurological side effects due to the limited evidence on optimal pain management protocols.

Low evidencePractice changing

Study snapshot

Design

Scoping review following PRISMA-ScR guidelines

Population

Pediatric patients undergoing craniotomies

Intervention

Various postoperative analgesic approaches including opioids, NSAIDs, acetaminophen, and sedatives

Comparator

Different analgesic regimens compared across studies

Primary outcome

Synthesis of evidence on analgesic efficacy and safety in pediatric craniotomy patients

Why it matters

Postoperative pain management in pediatric craniotomy patients has lacked consolidated evidence and clear guidelines, with concerns about opioid side effects interfering with neurological assessments. This scoping review synthesizes available evidence on analgesic approaches and provides recommendations for multimodal pain management strategies. Clinicians should consider adopting multimodal analgesic approaches tailored to pediatric patients while monitoring for neurological side effects.

Practice change

Confirms current practice of considering multimodal analgesic approaches for pediatric craniotomy patients.

More context

Key details

  • Scoping review following PRISMA-ScR guidelines identified 709 articles, with 24 meeting inclusion criteria
  • Post-craniotomy pain in children is generally superficial and somatic, involving scalp, pericranial muscles, and dura
  • Multimodal approaches targeting different pain mechanisms show efficacy
  • Opioids were used in 70.7% of patients, primarily morphine and codeine
  • NSAIDs/acetaminophen combinations and sedatives were also reported
  • Effective analgesia can reduce stress responses and chronic pain risk
  • Review provides evidence-based recommendations for analgesic selection and utilization

High-yield

A scoping review of studies found that multimodal analgesic approaches are effective for pediatric craniotomy pain, with opioids remaining commonly used but requiring careful monitoring due to potential interference with neurological examinations.

Clinical context

Managing postoperative pain in pediatric craniotomy patients remains challenging with limited consolidated evidence and guidelines. Opioids have limitations due to potential adverse effects and interference with neurological examinations.

Limitations

Scoping review methodology provides synthesis but not quantitative meta-analysis of treatment effectsLimited data available on postoperative outcomes and complications in included studies

Methodological critique

Scoping review provides synthesis but not quantitative treatment effect analysis.

Teaching pearl

When managing post-craniotomy pain in children, remember that a multimodal approach combining different analgesic classes may provide better pain control with fewer side effects than high-dose opioids alone.

Funding and COI

Not stated

Basic Science

Delay clazosentan initiation in SAH patients with active neurogenic pulmonary edema until pulmonary status stabilizes, as early administration may worsen lung injury.

OIn patients with subarachnoid hemorrhage and active neurogenic pulmonary edema, delay clazosentan administration until pulmonary status stabilizes, as early use may worsen lung injury based on preclinical findings.

Low evidencePractice changing

Study snapshot

Design

Laboratory investigation (preclinical)

Population

Male mice with endovascular perforation-induced subarachnoid hemorrhage

Intervention

Clazosentan administration at different time points after SAH

Comparator

Saline vehicle

Primary outcome

Lung water content and histopathological lung injury scores

Why it matters

Clazosentan is used to prevent cerebral vasospasm after aneurysmal SAH, but its safety in patients with neurogenic pulmonary edema has been uncertain due to pulmonary edema being a known side effect. This preclinical study suggests that early clazosentan administration exacerbates SAH-induced NPE, while delayed administration appears safe. Neurosurgeons should consider delaying clazosentan initiation in SAH patients with active NPE until pulmonary edema shows improvement.

Practice change

May support delaying clazosentan initiation in SAH patients with active neurogenic pulmonary edema until pulmonary edema shows improvement.

More context

Key details

  • Preclinical study using mouse endovascular perforation SAH model

High-yield

In a mouse model of SAH, early clazosentan administration significantly worsened neurogenic pulmonary edema, while delayed administration showed no detrimental effects on lung injury.

Clinical context

Clazosentan is used to prevent cerebral vasospasm following aneurysmal SAH, but its safety in patients with neurogenic pulmonary edema is unclear due to pulmonary edema being a known side effect.

Limitations

Preclinical mouse model may not fully translate to human pathophysiologySmall sample sizes typical of laboratory investigations limit statistical power

Methodological critique

Preclinical mouse model may not fully translate to human pathophysiology.

Teaching pearl

When considering clazosentan for vasospasm prophylaxis in SAH patients with pulmonary edema, remember that timing matters—early administration may exacerbate lung injury, while delayed treatment appears safer.

Funding and COI

Not stated

Trials to Know

Why it matters

This recruiting trial may offer eligible patients access to novel interventions.

Why it matters

This recruiting trial may offer eligible patients access to novel interventions.

From the Preprint Wire

Bariatric Surgery History Increases Portal Hypertension Risk in Alcohol-Associated Hepatitis

Preprint • From the Preprint Wire • medrxiv • 2026-03-14

Why it matters

This preprint suggests patients with a history of bariatric surgery who develop alcohol-associated hepatitis face a significantly higher risk of portal hypertension complications, which is crucial for neurosurgeons managing conditions like variceal bleeding or hepatic encephalopathy. As an unreviewed study, it highlights potential long-term hepatologic risks that could inform preoperative counseling and multidisciplinary care for neurosurgical patients with this history. However, neurosurgeons should interpret these findings cautiously until peer-reviewed validation.

More context

Key details

  • Study used TriNetX US Collaborative Network with 772 matched patients per cohort after propensity score matching on 44 variables.
  • Found significantly higher risk of portal hypertension events (HR 1.519, p=0.003) but no significant differences in liver transplantation or all-cause mortality.
  • Authors recommend enhanced postoperative counseling and liver surveillance for bariatric surgery patients, which could be relevant in neurosurgical preoperative assessments.

Spatial Immune Landscape of Mismatch Repair Deficient Endometrial Cancer

Preprint • From the Preprint Wire • medrxiv • 2026-03-14

Why it matters

This preprint explores the tumor microenvironment in dMMR endometrial cancer, which is relevant to neurosurgeons as these tumors can metastasize to the brain and may require neurosurgical intervention. Understanding immune cell spatial organization could help predict recurrence and response to immunotherapy, potentially guiding treatment decisions for metastatic cases. However, as a preprint, this work has not undergone peer review and should be interpreted cautiously.

More context

Key details

  • Used multiplex immunofluorescence imaging with a 36-antibody panel on 16 dMMR endometrial tumors to analyze immune cell composition and spatial relationships.
  • Non-recurrent tumors (n=10) had higher intratumoral CD8 T-cells, tumor cell enrichment around CD8+ T cells, and PD-1Low CD4 T-cell proportions.
  • Recurrent tumors (n=6) showed higher CD4+ T cell proportions and distinct macrophage spatial patterns, with ICI responders having more PD-1+Ki67+ CD8+ T cells and dispersed macrophages co-localized with PD-1+ CD8 T cells.