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Digest

The Weekly Signal

Published July 5, 2026

Executive Summary

This week's digest highlights: Preliminary evidence; confirm full-text methods and endpoints before changing practice. Preliminary evidence; confirm full-text methods and endpoints before changing practice. Routine postoperative activity restrictions after lumbar microdiscectomy are not supported by evidence; patients can be encouraged to resume normal activities as tolerated...

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

Preliminary evidence; confirm full-text methods and endpoints before changing practice.

High evidencePractice changing

Study snapshot

Design

Systematic review

Population

Patients undergoing transsphenoidal resection of sellar or parasellar lesions

Intervention

Transsphenoidal surgery (endoscopic or microscopic)

Comparator

None (single-arm synthesis)

Primary outcome

Postoperative visual outcomes (improved, normalized, unchanged, worsened)

Why it matters

Visual outcomes after transsphenoidal surgery for sellar/parasellar lesions were known to improve in many patients, but reporting was inconsistent. This systematic review of 236 studies found that 76% of patients with preoperative visual loss improved postoperatively, with 73% improvement in visual field defects and 64% in visual acuity. Clinicians should counsel patients that most experience visual improvement, but standardized outcome reporting is needed.

Practice change

Confirms current practice that transsphenoidal surgery improves vision in most patients, but highlights need for standardized reporting.

More context

Key details

  • Systematic review of 236 studies following PRISMA guidelines.
  • Pituitary adenomas accounted for 80% of cases, craniopharyngiomas 14%, meningiomas 4%.
  • Preoperative visual loss, field defects, and acuity impairment present in 55%, 51%, and 37% of patients, respectively.

High-yield

Postoperative visual improvement occurred in 76% of patients with preoperative visual loss, 73% with visual field defects, and 64% with visual acuity impairment.

Clinical context

Transsphenoidal surgery is the standard approach for sellar lesions, but visual outcome reporting is inconsistent. This review summarizes available data to guide patient counseling.

Limitations

High heterogeneity across studies in definitions and reporting of visual outcomes.Publication bias may overestimate improvement rates.

Methodological critique

High heterogeneity and incomplete outcome reporting limit the strength of pooled estimates.

Teaching pearl

When counseling patients with sellar lesions and visual deficits, you can expect improvement in about three-quarters of cases, but warn that 2-11% may worsen.

Funding and COI

Not stated

Spine

Routine postoperative activity restrictions after lumbar microdiscectomy are not supported by evidence; patients can be encouraged to resume normal activities as tolerated.

High evidencePractice changing

Study snapshot

Design

Multicenter, single-blind, randomized controlled trial

Population

Adults 18-75 years undergoing unilateral lumbar microdiscectomy for radiculopathy with concordant MRI findings

Intervention

Postoperative activity restrictions (limited sitting, bending, lifting, twisting for 1 month)

Comparator

No specific restrictions (encouraged to resume normal activities)

Primary outcome

Composite of ≥18-point VAS back improvement, ≥25-point VAS leg improvement, ≥15-point ODI improvement, and no reoperation at 12 months

Why it matters

Postoperative activity restrictions after lumbar microdiscectomy are common but lack evidence. This RCT found no difference in primary composite outcome (41.6% vs 36.4%, p=0.45) or reherniation rates (10.1% vs 14.1%, p=0.61) between restricted and unrestricted groups. Surgeons can consider eliminating routine activity restrictions, as they do not improve outcomes and adherence is poor.

Practice change

May support eliminating routine activity restrictions after lumbar microdiscectomy, as they do not improve outcomes.

More context

Key details

  • RCT at 3 centers in Australia; 200 patients randomized to restricted (n=101) or unrestricted (n=99) activity for 1 month post-microdiscectomy.

High-yield

See source article for primary outcome data.

Clinical context

Postoperative activity restrictions after lumbar microdiscectomy are commonly prescribed to prevent reherniation, but evidence is lacking. This trial aimed to assess their efficacy.

Limitations

High attrition (29%) and poor adherence to restrictions (10%) limit the ability to detect true differences.Single-blinded design (patients aware of group assignment) may introduce bias.

Methodological critique

High attrition (29%) and poor adherence weaken the intention-to-treat analysis.

Teaching pearl

Activity restrictions after lumbar microdiscectomy do not improve outcomes and patients rarely follow them anyway. Focus on early mobilization and reassurance.

Funding and COI

Not stated

Functional

Impact of Subthalamic Nucleus Deep Brain Stimulation on Gastrointestinal Symptoms and Gastric Emptying in Parkinson's Disease: A Systematic Review and Meta-Analysis.

Research • Functional • Neuromodulation : journal of the International Neuromodulation Society • 2025-09-05

STN-DBS may be considered for PD patients with significant GI symptoms, as it provides sustained improvement in gastric motility and symptom scores up to months.

High evidencePractice changing

Study snapshot

Design

Systematic review and meta-analysis

Population

Patients with Parkinson's disease undergoing bilateral STN-DBS

Intervention

Bilateral subthalamic nucleus deep brain stimulation (STN-DBS)

Comparator

Pre-DBS baseline (medication on/off states)

Primary outcome

Changes in gastrointestinal domain of Non-Motor Symptoms Scale (NMSS-GI) and 13CO2 excretion time (Tmax)

Why it matters

Before this study, the effect of STN-DBS on gastrointestinal symptoms in Parkinson's disease was unclear. This meta-analysis of 379 patients shows that STN-DBS significantly reduces GI symptoms (NMSS-GI domain) and improves gastric emptying (Tmax13CO2) with sustained benefits up to 12 months. Clinicians should consider STN-DBS as a potential adjunctive therapy for PD patients with bothersome GI symptoms, though long-term data are needed.

Practice change

Confirms current practice; STN-DBS may be considered for PD patients with GI symptoms, but further long-term studies are needed.

More context

Key details

  • Systematic review and meta-analysis of 8 observational studies (N=379) evaluating bilateral STN-DBS for GI symptoms in PD.

High-yield

See source article for primary outcome data.

Clinical context

Gastrointestinal symptoms are common non-motor features in Parkinson's disease, affecting quality of life. The effect of STN-DBS on GI motility has been unclear.

Limitations

All included studies were observational, introducing potential selection bias.Heterogeneity in GI symptom assessment and gastric emptying measurement methods across studies.

Methodological critique

Meta-analysis of observational studies with moderate heterogeneity; no randomized controlled trials included.

Teaching pearl

When evaluating PD patients for DBS, consider autonomic symptoms like GI dysfunction as potential non-motor targets; STN-DBS may improve gastric motility beyond motor benefits.

Funding and COI

Not stated

General Neurosurgery

May consider adjunctive MMAE for cSDH evacuation in selected patients, but await full trial results for definitive guidance.

High evidencePractice changing

Study snapshot

Design

Randomized controlled trial (interim analysis) with systematic review

Population

Adults with symptomatic chronic subdural hematoma requiring surgical evacuation

Intervention

Burr hole evacuation plus middle meningeal artery embolization (MMAE)

Comparator

Burr hole evacuation alone

Primary outcome

Recurrence within 3 months (defined by volume, midline shift, or need for reoperation)

Why it matters

Before this study, MMAE for cSDH showed promise in retrospective series but lacked randomized evidence. This interim analysis of the G-MEMBRANE RCT and systematic review provides early randomized data suggesting MMAE may reduce recurrence. Clinicians should await full results before changing practice, but may consider MMAE for high-risk patients in experienced centers.

Practice change

May support considering MMAE as an adjunct to surgical evacuation for cSDH, but full results are needed before widespread adoption.

More context

Key details

  • G-MEMBRANE is a randomized controlled trial comparing burr hole evacuation alone vs evacuation plus MMAE for cSDH.
  • Interim analysis triggered early stopping due to significant reduction in recurrence (p<0.0031).
  • High dropout rate of 31.2% due to patient non-compliance and logistical issues.
  • Systematic review of RCTs on MMAE for cSDH was also performed.

High-yield

See source article for primary outcome data.

Clinical context

Chronic subdural hematoma recurrence after burr hole evacuation ranges from -40%. MMAE has been proposed as an adjunct to reduce recurrence.

Limitations

Interim analysis with high dropout rate (31.2%) limits generalizability.Single-center design and lack of blinding due to visible embolization material.

Methodological critique

High dropout rate and single-center design limit internal validity.

Funding and COI

Funded by German Social Accident Insurance (research project FR341)

Basic Science

TBI Biomarker Improvements Following Rodent Decompressive Craniectomy and Motor Outcome Validation of Early Cranioplasty.

Research • Basic Science • The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association • 2025-07-15

Preclinical evidence; no immediate practice change pending clinical validation.

Low evidencePractice changing

Study snapshot

Design

Basic science (preclinical)

Population

CD1 mice and Long-Evans rats with moderate-to-severe TBI

Intervention

Decompressive craniectomy followed by early or delayed alloplastic cranioplasty

Comparator

Sham, TBI only, TBI-DC without cranioplasty

Primary outcome

GFAP and UCH-L1 levels; motor performance on beam walk

Why it matters

Before this study, the utility of neuroinflammatory biomarkers GFAP and UCH-L1 in decompressive craniectomy (DC) patients and the optimal timing of cranioplasty for motor recovery were unclear. This study demonstrates that DC reduces acute biomarker elevation and that early cranioplasty improves motor outcomes in a rodent TBI model. Clinicians may consider early cranioplasty to enhance neurological recovery after DC, though human validation is needed.

Practice change

Does not change current clinical practice but may inform future translational work.

More context

Key details

  • Rodent model used closed cortical impact to induce moderate-to-severe TBI.
  • GFAP and UCH-L1 were quantified in CD1 mice in sham, TBI, and TBI-DC groups.
  • Early cranioplasty group received alloplastic cranioplasty soon after DC.
  • Beam walk test assessed motor proficiency in Long-Evans rats.
  • 2-way ANOVA with Dunnett's post hoc test determined group differences.
  • By day 7, biomarker levels converged (P>.05), indicating acute neuroinflammation resolution.

High-yield

See source article for primary outcome data.

Clinical context

Decompressive craniectomy is used to manage moderate-to-severe TBI, but the utility of biomarkers GFAP and UCH-L and optimal cranioplasty timing are unclear.

Limitations

Preclinical rodent model may not fully replicate human TBI pathophysiology.Small sample sizes and lack of blinding or randomization details limit internal validity.

Methodological critique

Preclinical study with limited generalizability and no blinding or randomization details.

Teaching pearl

When counseling residents on TBI management, emphasize that decompressive craniectomy may reduce acute neuroinflammatory biomarkers, and early cranioplasty could be considered to optimize motor recovery, though these findings are preliminary and require clinical translation.

Funding and COI

Not stated

Trials to Know

Stereotactic Radiosurgery Dose Escalation for Brain Metastases

Trial • Trials to Know • ClinicalTrials.gov • 2026-07-05

Why it matters

This phase I trial evaluates dose escalation of stereotactic radiosurgery (SRS) for brain metastases, aiming to improve local control while minimizing toxicity. For neurosurgeons, it addresses the critical question of optimal SRS dosing in an era of increasing use of SRS alone, potentially expanding treatment options for patients with limited intracranial disease.

More context

Key details

  • Phase I, recruiting

IA Lidocaine and Methylprednisolone for Headache Associated With Subarachnoid Hemorrhage

Trial • Trials to Know • ClinicalTrials.gov • 2026-07-05

Why it matters

This Phase 2 trial tests intra-arterial lidocaine and methylprednisolone for refractory headache after subarachnoid hemorrhage (SAH), a common and debilitating complication with limited treatment options. If effective, this targeted intervention could reduce opioid use and improve recovery in SAH patients, addressing a significant gap in post-hemorrhagic pain management.

More context

Key details

  • Phase 2, recruiting

ASP2246 for Post-Stroke Movement Disorders

Trial • Trials to Know • ClinicalTrials.gov • 2026-07-05

Why it matters

This phase 1/2 trial evaluates ASP2246, a novel agent, combined with brain surgery and rehabilitation for chronic ischemic stroke patients with persistent movement problems. It addresses the gap in effective treatments for motor deficits beyond the acute phase, potentially offering a new surgical intervention strategy for neurosurgeons managing post-stroke disability.

More context

Key details

  • Phase 1/2, recruiting

From the Preprint Wire

Virtual RNS Implantation: From Intracranial Connectivity to Optimized Lead Placement

Preprint • From the Preprint Wire • medrxiv • 2026-06-22

Why it matters

This unreviewed preprint proposes a novel method using pre-implantation intracranial EEG connectivity to predict responsive neurostimulation (RNS) outcomes and generate patient-specific 3D maps for optimal lead placement. For neurosurgeons, this could transform RNS surgical planning from a trial-and-error approach to a network-guided strategy, potentially improving seizure outcomes in drug-resistant epilepsy.

More context

Key details

  • Developed a composite score combining standard deviation and kurtosis of interictal iEEG connectivity distributions to predict RNS outcome.
  • Validated across three independent epilepsy centers (HUP, NYU, UCSF) with 68% accuracy in the validation cohort (55% sensitivity, 88% specificity).
  • Generated patient-specific 3D maps of predicted RNS efficacy for 200 simulated lead configurations, showing responders had higher spatial scores in favorable regions.

DeepPLL: Synchronizing Non-Invasive Brain Stimulation with Deep Brain Stimulation

Preprint • From the Preprint Wire • medrxiv • 2026-06-22

Why it matters

This unreviewed preprint introduces a novel open-source device that synchronizes deep brain stimulation (DBS) with non-invasive transcranial alternating current stimulation (tACS) in real time. For neurosurgeons, this could enable multi-site network modulation without additional invasive implants, potentially expanding therapeutic options for conditions like Parkinson's disease.

More context

Key details

  • DeepPLL uses an isolated analog front-end to extract DBS EEG artifacts and a phase-locked loop for timing stabilization.
  • The system offers 1-degree phase resolution and low-jitter TTL outputs for driving external stimulators.
  • Feasibility was demonstrated in two individuals with Parkinson's disease undergoing subthalamic DBS.