Executive Summary
This week's digest highlights: Consider using dual-polymer gel during single-level discectomy to enhance pain relief in patients with severe leg and back pain. PEEK or UHMWPE are recommended as preferred alloplastic materials for cranioplasty when autologous bone is not an option. Preliminary evidence suggests that collateral circulation and etiology may influence functional outcomes in endovascular thrombectomy...
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
Brain metastases from colorectal cancer - a retrospective dual center study.
Research • Tumor / Skull Base • Journal of neuro-oncology • 2026-03-24
Preliminary evidence; confirm full-text methods and endpoints before changing practice.
OWhile surgical resection of brain metastases from colorectal cancer may improve survival in select patients, clinicians should exercise caution and await further validation of these findings before altering treatment protocols.
Study snapshot
Design
Retrospective dual-center cohort study
Population
Patients with colorectal cancer and brain metastases treated at two German cancer centers
Intervention
Surgical resection of brain metastases
Comparator
No surgical resection
Primary outcome
Overall survival from brain metastasis diagnosis
Why it matters
Brain metastases from colorectal cancer are rare but increasing, with limited evidence to guide management. This large dual-center study confirms that surgical resection and performance status are key determinants of survival. Clinicians should consider aggressive local therapy for selected patients with good performance status and limited extracranial disease.
Practice change
Confirms current practice of considering surgical resection for selected patients with good performance status.
More context
Key details
- Retrospective dual-center study (2000-2024)
- 61.6% male, mean age at BM diagnosis 65.1 years
- Synchronous BM in 11.1%, metachronous BM mean interval 40.5 months
- Liver metastases in 50.9%, lung in 64.2%, bone in 22.6%
- KRAS mutations in 54.2% of tested cases
- Multivariable analysis showed surgical resection (HR 0.51) and KPS as independent prognostic factors
High-yield
Surgical resection of brain metastases in colorectal cancer patients is associated with improved survival.
Clinical context
Brain metastases from colorectal cancer occur in 1-4% of patients and indicate advanced systemic disease with poor prognosis. Optimal therapeutic strategies remain uncertain.
Limitations
Retrospective design with potential selection biasSubstantial missing data for multivariable analysis (only 39.1% complete cases)
Methodological critique
Retrospective design with referral bias between centers affects generalizability.
Teaching pearl
When considering surgery for colorectal brain mets, look beyond the intracranial disease—patients with better KPS and fewer extracranial metastases are the best candidates.
Funding and COI
Not stated
Functional
Between Surgery and Science: Patient Journeys in Deep Brain Stimulation Local Field Potential Research.
Research • Functional • Neuromodulation : journal of the International Neuromodulation Society • 2026-03-30
Preliminary evidence; confirm full-text methods and endpoints before changing practice.
OWhile most patients report high satisfaction with externalized DBS LFP research participation, clinicians should communicate potential practical burdens and ensure transparency about the study's preliminary nature before altering patient care practices.
Study snapshot
Design
Mixed-methods survey study
Population
47 patients with Parkinson's disease, essential tremor, or dystonia who participated in externalized DBS LFP research
Intervention
Participation in postoperative externalized DBS LFP research
Comparator
None
Primary outcome
Patient satisfaction, motivations, and perceived burden
Why it matters
Patient experiences in externalized DBS research were previously underexplored, despite decades of LFP studies. This study adds that participants report high satisfaction (88.7% positive) primarily motivated by altruism, with minimal drawbacks for most (80.4% none). Clinicians should ensure thorough communication of trial findings to participants, as they value this dissemination.
Practice change
Confirms current practice of transparent communication with research participants.
More context
Key details
- Mixed-methods study using telephone surveys and semistructured interviews
- Altruism and wanting to give back were primary motivations
- Most participants did not perceive personal benefits
- Some experienced reassurance, knowledge gain, and minimal discomfort
- Main burdens included experimental paradigms, travel, costs, and longer hospital stays
- Participants emphasized importance of receiving information about trial findings
- Conducted at St George's Hospital, London between 2019-2024
High-yield
Most patients (88.7%) reported positive experiences participating in externalized DBS LFP research, driven by altruism rather than personal benefit.
Clinical context
LFP recordings from DBS leads provide insights into PD, ET, and dystonia pathophysiology. Patient experiences in these studies are underexplored.
Limitations
Single-center design limits generalizabilityRelies on self-reported experiences without objective measures
Methodological critique
Single-center design with self-reported data.
Teaching pearl
When discussing externalized DBS research participation with patients, emphasize that most find it positive and are motivated by helping others, not personal gain—but be transparent about practical burdens like travel and longer stays.
Funding and COI
Not stated
General Neurosurgery
Complications of Alloplastic Graft Materials Used in Cranioplasty: Systematic Review and Network Meta-Analysis.
Research • General Neurosurgery • Medical science monitor : international medical journal of experimental and clinical research • 2026-03-10
Consider PEEK or UHMWPE as preferred alloplastic options for cranioplasty when autologous bone is not feasible.
OWhen selecting alloplastic materials for cranioplasty, prioritize PEEK or UHMWPE to reduce complication rates, while also considering individual patient factors such as defect characteristics and cost.
Study snapshot
Design
Systematic review and network meta-analysis
Population
Adult patients requiring cranioplasty with alloplastic materials
Intervention
Various alloplastic materials (PMMA, titanium, PEEK, hydroxyapatite cement, etc.)
Comparator
Direct and indirect comparisons between materials
Primary outcome
Post-cranioplasty complications (infection, implant exposure, re-surgery)
Why it matters
Cranioplasty complication rates are substantially higher than routine neurosurgical procedures, but comparative effectiveness of alloplastic materials remained unclear. This network meta-analysis demonstrates that PEEK and UHMWPE show the best performance profiles for minimizing complications. Neurosurgeons could consider PEEK or UHMWPE as preferred options when alloplastic materials are indicated.
Practice change
Could consider PEEK or UHMWPE as preferred alloplastic options when autologous bone is not feasible for cranioplasty.
More context
Key details
- Systematic review and network meta-analysis of 24 studies (2777 patients)
- Compared PMMA, titanium, PEEK, hydroxyapatite cement, and other alloplastics
High-yield
PEEK and ultra-high-molecular-weight polyethylene (UHMWPE) demonstrated the best performance profiles for minimizing cranioplasty complications in network meta-analysis.
Clinical context
Cranioplasty has higher complication rates than routine neurosurgical procedures. Various alloplastic materials are available, but their comparative effectiveness remains unclear.
Limitations
High heterogeneity among included studies prevented network meta-analysis for overall complicationsOver half of included studies had moderate to high risk of bias
Methodological critique
High heterogeneity prevented network meta-analysis for overall complications.
Teaching pearl
When choosing cranioplasty materials, remember that PEEK and UHMWPE consistently rank best for minimizing complications—but always balance this with patient-specific factors like defect location and cost constraints.
Funding and COI
Not stated
From the Preprint Wire
Mechanical Dynamics of Glioblastoma Invasion in 3D Matrigel
Preprint • From the Preprint Wire • biorxiv • 2026-04-03
Why it matters
This preprint offers a quantitative mechanical analysis of glioblastoma (GBM) invasion using patient-derived neurospheres in 3D Matrigel, which could inform strategies to limit tumor spread and improve surgical outcomes. As an unreviewed preprint, it provides novel insights into the cytoskeletal mechanisms driving GBM invasion, but its findings require validation before clinical application.
More context
Key details
- Patient-derived GBM neurospheres showed elongated, protrusion-rich morphology with F-actin at the periphery and microtubules along shafts, indicating mesenchymal-like invasion.
- 3D traction force microscopy revealed progressive bead clustering, increasing cumulative traction forces, and hotspots near protrusion tips during invasion.
- Perturbation studies identified actin polymerization as essential for invasion, myosin II for traction generation, and microtubules for directional persistence, with residual invasion persisting under myosin II inhibition without MMP dependence.
Patient-Specific CFD Analysis of Carotid Webs: Hemodynamics and Viscosity Effects
Preprint • From the Preprint Wire • medrxiv • 2026-03-20
Why it matters
This preprint investigates carotid webs (CaWs), a known but understudied cause of ischemic stroke, using computational fluid dynamics (CFD) to analyze hemodynamic metrics that could inform stroke risk stratification and surgical decision-making. For neurosurgeons managing carotid pathology, it offers preliminary insights into potential biomechanical markers for symptomatic vs. asymptomatic CaWs, though it is crucial to note this is an unreviewed preprint and findings require validation.
More context
Key details
- Carotid webs showed greater inter-patient variability in hemodynamic metrics than normal bifurcations, but with substantial overlap between groups.
- Blood viscosity models (Newtonian, Carreau-Yasuda, Casson) had minimal impact (<2% differences) on flow patterns in the simulations.
- Recirculation zones predicted by CFD corresponded to delayed contrast clearance on digital subtraction angiography (DSA), supporting model validity.