Month: February 2026

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Intraoperative Evaluation of Dural Arteriovenous Fistula Obliteration Using FLOW 800 Hemodynamic Analysis

Operative Neurosurgery 30:250–259, 2026

This clinical study evaluates intraoperative indocyanine green videoangiography with FLOW 800 software to quantify hemodynamic changes during cranial and spinal dural arteriovenous fistula (dAVF) microsurgical obliteration. Using four FLOW 800 metrics across venous regions of interest, the authors compare pre- and post-obliteration measurements confirmed by intraoperative digital subtraction angiography.

Key findings identify increased Delay Time and decreased Speed as consistent, significant markers of successful dAVF obliteration, supported by nonparametric tests, logistic and Bayesian regression, and PCA visualization. The study suggests FLOW 800 as a practical adjunct to intraoperative imaging, while acknowledging limitations from small sample size and ROI selection variability.

Key Hemodynamic Parameters: Intraoperative FLOW 800 analysis of indocyanine green videoangiography quantifies four hemodynamic parameters—Delay Time, Speed, Time to Peak, and Rise Time—across venous drainage regions before and after dAVF (dural arteriovenous fistula) obliteration.

Most Sensitive Indicators: Delay Time (time for dye to reach ROI) and Speed (rate of dye flow) are the most sensitive and consistent hemodynamic indicators of successful dAVF obliteration, with Delay Time increasing and Speed decreasing significantly post-obliteration.

Statistical Significance: Delay Time increased from a median of 2.07s to 7.86s (P = .020), and Speed decreased from 13.5 s⁻¹ to 5.5 s⁻¹ (P = .029), both changes being statistically significant; Time to Peak and Rise Time showed no significant association.

Predictive Value: A 50% increase in Delay Time is associated with 2.16 times higher odds of achieving obliteration (OR = 4.59), while a 50% decrease in Speed is associated with 1.28 times higher odds; Delay Time and Speed are the strongest predictors in regression analyses.

Clinical Utility: FLOW 800 provides real-time, semiquantitative intraoperative feedback, supporting its use as a noninvasive adjunct to traditional imaging (like intraoperative DSA) for confirming dAVF obliteration, especially where DSA is unavailable.

Study Limitations: The study is limited by small sample size (8 patients, 14 ROIs), single-center design, and possible variability in ROI selection; findings require validation in larger, multicenter studies.

Practical Considerations: Complete visualization of venous outflow is necessary for FLOW 800 utility; current evidence supports its use as a complementary tool rather than a replacement for DSA.

Clinical Outcome: All patients in the study had successful dAVF obliteration confirmed by intraoperative DSA, no complications or recurrences at median 19.4 months follow-up, and FLOW 800 changes were consistent with successful surgical outcomes.

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Predicting chronic subdural hematoma risk in elderly patients with mild traumatic brain injury

Acta Neurochirurgica (2026) 168:40

This study develops and validates a concise bedside risk score to predict chronic subdural hematoma (CSDH) within 2–12 weeks after mild traumatic brain injury in patients aged 65+. Using a large retrospective cohort (7,246 events) and multivariable modeling, pathological CT at presentation, male sex, older age, and renal failure emerged as key predictors.

The score-based model (including anticoagulant use by expert choice) achieved AUROC 0.76 and 86% sensitivity at the chosen threshold, classifying ~61% as high-risk. Authors propose this tool to guide targeted surveillance and earlier intervention, while noting limitations from retrospective data and need for external validation.

Pathological CT Findings: Pathological findings on initial head CT after mild traumatic brain injury (TBI) are the strongest predictor for developing chronic subdural hematoma (CSDH) within 2–12 weeks in elderly patients.

Key Risk Factors: Older age, male sex, and renal failure are also significant independent predictors for CSDH following mild TBI.

Anticoagulant Use: Chronic use of anticoagulant medications showed a trend toward increased risk but was not statistically significant in this cohort; antiplatelet use was not associated with increased risk.

Prediction Model: A simple score-based risk model was developed, incorporating pathological CT (14 points), male sex (4), renal failure (4), anticoagulant use (4), and age (1 point per 5 years over 65), with a threshold of 5 points or higher identifying high-risk patients.

Model Performance: The risk model achieved an area under the ROC curve (AUROC) of 0.76 and a sensitivity of 86% for detecting CSDH, but the positive predictive value was low (1.6%) due to the rare occurrence of the outcome.

Clinical Implications: Early identification of high-risk patients may enable targeted surveillance, timely CT scanning, and consideration of non-surgical management options such as corticosteroids or middle meningeal artery embolization.

Population Impact: The incidence of CSDH is rising globally due to population aging and increased use of antithrombotic agents, with elderly adults being particularly at risk.

Study Scope: The findings support the use of bedside risk stratification in the emergency department for elderly patients with mild TBI, but further research is needed before widespread clinical implementation.

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Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Surgical Resection for the Treatment of Patients With Vestibular Schwannomas: Update

Neurosurgery 98:272–277, 2026

These updated Congress of Neurological Surgeons guidelines review surgical management of sporadic vestibular schwannomas using literature from 2015–2022, reaffirming many prior recommendations and highlighting persistent evidence gaps. Key recommendations address approach selection (middle fossa, retrosigmoid, translabyrinthine), hearing-preservation surgery options, and counseling patients about outcomes after prior stereotactic radiosurgery.

The document details systematic review methods, inclusion criteria, and evidence grading, noting most data are class III and insufficient to prove superiority of specific surgical approaches for many questions. It emphasizes individualized treatment decisions, need for multicenter registries or trials, and future research priorities to resolve unanswered clinical issues.

Surgical Approach Selection: No surgical approach (middle fossa, retrosigmoid, or translabyrinthine) has proven superiority for facial nerve preservation or gross total resection in sporadic vestibular schwannoma; choice depends on individual patient factors and tumor characteristics.

Hearing Preservation: Hearing preservation surgery via middle fossa or retrosigmoid approach may be considered for patients with good preoperative hearing as an alternative to observation, but evidence for long-term superiority is limited.

Subtotal Resection and Radiosurgery: Subtotal resection followed by stereotactic radiosurgery does not have sufficient evidence to support better facial nerve or hearing outcomes compared to complete resection.

Microsurgery After SRS: Patients undergoing microsurgical resection after prior stereotactic radiosurgery should be counseled about increased risk of subtotal resection and worse facial nerve function.

Trigeminal Neuralgia: Surgical resection may provide better relief of trigeminal neuralgia symptoms compared to stereotactic radiosurgery in patients with sporadic vestibular schwannoma.

Balance and Observation: There is insufficient evidence to support surgery or radiosurgery for improving preoperative balance problems, and no clear evidence that surgery should be primary treatment for small tumors eligible for observation.

Evidence Quality: All reviewed evidence is class III (retrospective series, flawed controls), with significant potential for bias and limitations in drawing strong conclusions.

Future Directions: Improved data from multicenter registries or randomized trials are needed to clarify optimal management, as current recommendations reflect standard practice but lack high-level evidence for many questions.

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Shifts in epilepsy treatment: a 12-year review of surgical approaches and outcomes in lesional and nonlesional epilepsy

J Neurosurg 144:259–272, 2026

This study analyzes national inpatient trends from 2009–2020 comparing lesional and nonlesional epilepsy patients who underwent surgical or neuromodulation treatments. Using NIS data with propensity score matching, it reports demographic differences, socioeconomic disparities, and shifting utilization patterns across VNS, RNS, DBS, resection, radiosurgery, and LITT.

The findings reveal increasing adoption of RNS and LITT, declining VNS and radiosurgery, higher costs for most interventions, and shorter length of stay with LITT. Persistent racial and income-based inequities in access and differing outcomes by lesion status prompt calls for tailored care and further cost-effectiveness and long-term outcome studies.

Distinct Patient Profiles: Lesional epilepsy patients are older, more likely male, have higher comorbidity burdens, and higher income/Medicare coverage compared to nonlesional epilepsy patients, who are more prevalent in lower income quartiles and rely more on Medicaid or private insurance.

Surgical Treatment Trends: Use of responsive neurostimulation (RNS) and laser interstitial thermal therapy (LITT) increased significantly for both lesional and nonlesional epilepsy from 2009–2020, while vagus nerve stimulation (VNS) declined for nonlesional epilepsy; deep brain stimulation (DBS) and radiosurgery declined for both groups.

Resective Surgery Patterns: Resective surgery utilization increased significantly for nonlesional epilepsy, but not for lesional epilepsy, indicating a growing acceptance of surgery in nonlesional cases despite the absence of overt lesions.

Healthcare Disparities: White patients, and those in higher income quartiles, have higher probabilities of receiving advanced treatments (VNS, RNS, DBS, resective surgery, radiosurgery); Black patients have persistently lower access regardless of income, and Hispanic patients show variable, income-dependent access.

Outcomes by Modality: RNS and LITT are associated with shorter or unchanged length of stay (LOS) and higher likelihood of routine discharge, while DBS and resective surgery increase LOS and costs; all surgical interventions increase hospital charges.

LITT Advantages: LITT is linked to decreased LOS and improved routine discharge rates, especially for lesional epilepsy, but incurs higher total charges compared to other modalities.

Mortality Impact: None of the interventions (VNS, RNS, DBS, resective surgery, radiosurgery, LITT) significantly affected mortality in either lesional or nonlesional epilepsy groups.

Need for Tailored Approaches: Persistent demographic, socioeconomic, and clinical differences between lesional and nonlesional epilepsy patients highlight the importance of individualized treatment strategies and further research on long-term and cost-effectiveness outcomes.

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Unraveling the cause of microspurs in spontaneous intracranial hypotension type 1: discogenic origin or calcified Hofmann’s ligament?

J Neurosurg Spine 44:315–319, 2026

This clinical study investigates the origin of ventral spinal microspurs causing spontaneous intracranial hypotension (SIH) type 1, comparing discogenic lesions with fibrotic tissue consistent with Hofmann’s ligament. Retrospective histopathological reanalysis of 27 surgically resected microspurs showed both discogenic and fibrotic origins, with 13 discogenic, 9 fibrotic, and 5 unclassifiable cases, and no significant differences in spur length, location, or CT density.

The authors conclude that ventral CSF leaks can arise from calcified intervertebral discs as well as calcified or fibrotic Hofmann’s ligaments, expanding the pathophysiological understanding of SIH and highlighting limitations from retrospective design, small sample size, and histological classification challenges.

Etiology of Microspurs: Microspurs causing ventral CSF leaks in spontaneous intracranial hypotension (SIH) type 1 can originate from both calcified intervertebral discs (discogenic) and calcified fibrous tissue associated with Hofmann’s ligament, not exclusively from disc material.

Histopathological Classification: Microspurs were histopathologically classified as either discogenic (cartilage/fibrocartilaginous tissue, often with secondary calcification) or fibrotic (hypercellular fibrous tissue with or without calcification, suggestive of Hofmann’s ligament).

Distribution: Most microspurs were located in the thoracic spine, with about one-third found at the cervicothoracic or thoracolumbar junctions, and the rest in the midthoracic region.

Imaging Findings: There was no statistically significant difference in microspur length or CT density (Hounsfield units) between discogenic and fibrotic (Hofmann’s ligament) origins, limiting the ability of imaging to distinguish between them preoperatively.

Clinical Implications: Both discogenic and fibrotic origins should be considered in the diagnosis and surgical planning for SIH with ventral CSF leaks, as relying solely on the discogenic theory may overlook alternative etiologies.

Pathophysiological Mechanism: Calcified microspurs, whether from discs or Hofmann’s ligament, may cause dural tears due to mechanical stress at spinal junctions or in regions with a narrow spinal canal.

Limitations: The study’s retrospective design, small sample size, and challenges in histopathological classification (lack of specific markers, possible sampling errors) limit the generalizability and precision of findings

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Are there distinct patterns of clinical deficits in cervical deformity? A discriminant analysis of health-related quality of life measures

J Neurosurg Spine 44:242–252, 2026

This clinical study analyzes preoperative health-related quality of life (HRQOL) measures in 134 adults with cervical deformity (CD) to identify distinct clinical deficit patterns and their association with radiographic morphotypes. Using factor and cluster analyses on NDI, mJOA, and SWAL-QOL items, four patient clusters emerged: sleep/fatigue, low neck disability, dysphagia with severe neck disability, and myelopathy.

These HRQOL-derived clusters correlated with specific radiographic types among severe deformities: cervicothoracic, focal, and flat-neck morphotypes. The findings support integrating patient-reported clinical dimensions into CD classification systems to guide tailored surgical planning and outcome assessment.

Distinct HRQOL Patterns: Four distinct patterns of health-related quality of life (HRQOL) deficits were identified in patients with cervical deformity: sleep/fatigue impairment, low neck disability, severe dysphagia and neck disability, and predominant myelopathy.

Cluster Analysis: Principal component and cluster analyses using NDI, mJOA, and SWAL-QOL questionnaires grouped patients into four homogeneous outcome clusters, each reflecting a unique constellation of clinical deficits.

Radiographic Associations: Each HRQOL deficit pattern was significantly associated with specific cervical deformity morphotypes: severe dysphagia/neck disability with cervicothoracic deformity, myelopathy with focal deformity, and sleep/fatigue or low disability with flat neck deformity.

Clinical Implications: Recognizing these HRQOL patterns may inform tailored management strategies, surgical planning, and prognosis for different cervical deformity subtypes.

Measurement Tools: The study utilized validated patient-reported outcome measures: Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) scale, and Swallowing Quality of Life (SWAL-QOL) questionnaire.

Radiographic Parameters: Comprehensive imaging assessments included cervical and spinopelvic alignment measures, such as cervical SVA, T1 slope, C2–7 lordosis, and T1S-CL mismatch.

Demographic Factors: No significant differences in age, sex, BMI, or most comorbidities were found across clusters, except for higher rates of depression and prior spine surgery in those with the most severe clinical deficits.

Classification Framework: Findings support integrating HRQOL measures with radiographic parameters for a more comprehensive, patient-centered cervical deformity classification system.

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Minimal Clinically Important Difference and Relative Change in Patient-Reported Outcomes After Surgery for Cervical Spondylotic Myelopathy: A Nationwide Study of 1,700 Patients

Neurosurgery 98:358–364, 2026

This nationwide registry study of 1,756 patients evaluates minimal clinically important difference (MCID) versus minimal clinically important relative change (MCIRC) for patient-reported outcomes after surgery for degenerative cervical myelopathy. Using anchor-based ROC analyses, the authors derive MCID and MCIRC thresholds for NRS neck/arm pain, EQ-5D index, EQ VAS, and NDI, and compare predictive accuracy for patient satisfaction at one year.

Key findings show MCIRC outperforms absolute MCID for NRS neck and arm pain and NDI, while MCID is superior for EQ-5D index and EQ VAS; selected thresholds are reported (e.g., NRS neck MCID −3 and MCIRC −47%). The study recommends incorporating MCIRC in future spine outcome guidelines to improve individualized assessment.

Minimal Clinically Important Difference (MCID): MCID represents the smallest absolute change in patient-reported outcome measures (PROMs) that signifies meaningful improvement for the patient after cervical spondylotic myelopathy surgery.

Minimal Clinically Important Relative Change (MCIRC): MCIRC is a proportional measure that reflects the minimum relative change in PROMs from baseline, making it more sensitive to changes in patients with extreme baseline values.

Calculation Methods: MCID and MCIRC values were determined using anchor-based approaches (with patient satisfaction as the anchor), ROC curve analysis with the Youden index, minimal detectable change (MDC), and mean change methods.

Key Thresholds Identified: MCID values were −3 for NRS neck pain, −2 for NRS arm pain, 0.09 for EQ5D index, 7 for EQ VAS, and −12 for NDI; MCIRC values were −47% for NRS neck pain, −40% for NRS arm pain, 386% for EQ5D index, 52% for EQ VAS, and −32% for NDI.

Predictive Accuracy: Relative change (MCIRC) provided greater predictive accuracy for identifying patient satisfaction in NRS neck/arm pain and NDI, while absolute difference (MCID) was superior for EQ5D index and EQ VAS.

Clinical Implication: MCIRC is recommended for PROMs influenced by baseline severity (like pain and disability scores), as it better accounts for individual variability and may enhance individualized patient assessment.

Study Population: The study analyzed 1,756 patients from the Swedish Spine Registry who underwent surgery for degenerative cervical myelopathy, with 59% reporting satisfaction at one year postoperatively.

Practical Recommendation: Incorporating MCIRC thresholds into future spine surgery outcome guidelines could improve evaluation of individualized patient recovery.

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Maximizing Tumor Resection and Managing Cognitive Attentional Outcomes: Measures of Impact of Awake Surgery in Glioma Treatment

Neurosurgery 98:365–375, 2026

This clinical research article compares awake surgery (AwS) and asleep surgery (AsS) in 64 glioma patients, focusing on attentional outcomes, extent of resection, and survival. Using neuropsychological testing at preoperative, 1-week, and 1-month intervals, combined with structural MRI, lesion-symptom mapping, and lesion network mapping, the study quantifies transient attentional decline and its anatomical correlates.

Results show AwS enables greater supramaximal resection of non–contrast-enhanced tumor tissue and improved overall survival for IDH wild-type glioblastoma, but is the sole predictor of transient postoperative attentional worsening at 1 week that recovers by 1 month. Analyses implicate left prefrontal/default mode network regions and large-scale attention networks in postoperative attentional changes, supporting tailored patient selection and development of intraoperative attention monitoring.

Awake Surgery (AwS) vs. Asleep Surgery (AsS): AwS enables a more extensive (supramaximal) resection of non–contrast-enhanced tumor areas in glioma patients compared to AsS, which correlates with improved oncological outcomes but higher transient attentional deficits postoperatively.

Transient Attentional Decline: Patients undergoing AwS experience a significant, temporary decline in attentional performance 1 week after surgery, with recovery to preoperative levels after 1 month; this effect is not observed with AsS.

Predictors of Attention Outcome: The only significant predictor of postoperative attentional deterioration is undergoing AwS; other factors such as age, sex, tumor location, grade, IDH mutation, and MGMT methylation do not significantly influence attentional decline.

Extent of Resection and Attention: Greater extent of resection (EOR) of non–contrast-enhanced tumor (especially >61%) is associated with immediate postoperative attentional worsening, but also with improved survival outcomes.

Oncological Benefit: In patients with IDH wild-type glioblastoma, AwS leads to significantly longer overall survival (mean 887.73 days) compared to AsS (mean 553.71 days), mainly due to lower non-contrast-enhanced residual tumor volume after AwS.

Functional Neuroanatomy: Postoperative attentional deficits are associated with lesions in the left prefrontal region of the default mode network (DMN); attention relies on distributed large-scale networks, including dorsal and ventral attention networks.

Patient Selection: Proper selection for AwS is crucial, especially for tumors involving anterior regions of the left DMN, and preoperative attentional abilities should be considered to balance oncological benefits and cognitive risks.

Monitoring Limitations: There are currently no established intraoperative tools for direct monitoring of attention during AwS; development of standardized, quantitative attention monitoring could further optimize outcomes.

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Impact of Clinical Variables and Aneurysm Morphology on Hemorrhage Volume and Clinical Outcomes

Neurosurgery 98:394–403, 2026

This study investigates determinants of aneurysmal subarachnoid hemorrhage (aSAH) volume and its effect on early clinical outcomes using objective, semiautomated CT quantification in 200 ruptured intracranial aneurysms. Multivariate analysis identified older age, higher Hunt and Hess score, and bifurcation aneurysm location as independent predictors of larger aSAH volume, while sex (female) correlated with lower volumes.

Outcome analysis stratified by age showed that in patients 18–64 years greater aSAH volume increased risk of delayed cerebral ischemia, clinical vasospasm, and 7-day mortality; in patients ≥65 years larger volume was associated only with 7-day mortality. The authors recommend multicenter studies using objective quantification to validate age-specific clinical implications.

Hemorrhage Volume Predictors: Larger aneurysmal subarachnoid hemorrhage (aSAH) volumes are associated with older age, higher Hunt and Hess (HH) scores at admission, and ruptured aneurysms located at arterial bifurcations, especially the basilar tip; women have lower hemorrhage volumes than men.

Aneurysm Morphology: Aneurysm size, aspect ratio (AR), size ratio (SR), and irregular morphology do not significantly influence aSAH volume, although bifurcation location is a strong predictor of increased hemorrhage volume.

Hemodynamics Over Morphology: Hemorrhage volume appears to be more influenced by cerebral flow dynamics and aneurysm location (bifurcation vs. sidewall) than by traditional morphological parameters such as size or shape.

Age-Dependent Outcomes: In patients aged 18–64 years, larger aSAH volume is linked to increased risk of delayed cerebral ischemia (DCI), clinical vasospasm, and 7-day mortality; in patients ≥65 years, larger volume is only associated with increased 7-day mortality, not DCI or vasospasm.

Elderly Population Specifics: Lower risk of vasospasm and DCI in elderly patients may be due to arteriosclerotic changes and larger cisternal spaces, which allow greater blood accumulation without corresponding clinical symptoms.

Objective Measurement: Use of semiautomated, machine learning-based tools (e.g., MATLAB segmentation) provides more reliable and reproducible quantification of hemorrhage volume compared to subjective grading systems.

Clinical Implications: Objective hemorrhage quantification could improve risk stratification, facilitate personalized treatment, and enhance understanding of blood clearance and outcomes after aSAH.

Research Recommendations: Multicenter studies using objective quantification methods are needed for validation and to refine management strategies for ruptured aneurysms, considering age-specific differences

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Do all patients with adult scoliosis need instrumented fusion from T10 to the pelvis?

J Neurosurg Spine 44:195–204, 2026

This clinical review addresses whether adult scoliosis uniformly requires instrumented fusion from T10 to the pelvis, presenting diagnostic frameworks, radiographic assessment, and surgical decision-making. It contrasts full-length thoracolumbar–pelvic constructs with shorter, focal interventions, emphasizing individualized selection based on pain generators, balance, deformity location, and comorbidities.

The article reviews indications for extending fusions to upper thoracic levels, risks such as proximal junctional kyphosis, and evidence supporting limited fusion or decompression-only strategies when focal pathology (fractional curve, foraminal stenosis, olisthesis) explains symptoms. Multiple case examples illustrate practical application of the decision algorithm and outcomes.

Individualized Treatment: Not all adult scoliosis patients require instrumented fusion from T10 to the pelvis; surgical decisions should be based on the patient’s symptoms, pain generator, spinal balance, and radiographic findings rather than a one-size-fits-all approach.

Pain Source Identification: Careful identification of the pain generator (scoliosis-related, neurogenic, facet, or sacroiliac) is critical; many patients have back pain unrelated to scoliosis and may benefit from focal or limited procedures instead of extensive fusion.

Fusion Level Selection: The choice of upper instrumented vertebra (UIV) depends on curve characteristics, presence of kyphosis, risk of proximal junctional kyphosis (PJK), and patient-specific factors; fusion may end at T10, upper thoracic, or even lumbar levels as appropriate.

Limited/Focal Surgery: In select cases, limited fusion (e.g., of the major curve, concavity, or fractional curve) or even decompression alone can be effective, especially for patients with focal symptoms or significant comorbidities who cannot tolerate extensive surgery.

Fractional Curve Fusion: Fusion of only the fractional curve (typically L4–S1) is effective for radicular pain referable to this segment; careful preoperative assessment of coronal alignment and curve type is necessary to avoid postoperative imbalance.

Radiographic-Clinical Correlation: Surgical planning should integrate both radiographic parameters (sagittal vertical axis, pelvic incidence–lumbar lordosis mismatch, coronal balance) and the patient’s clinical presentation, as discordance may require further investigation.

Risks of Extensive Fusion: Long-segment fusions (T10–pelvis or longer) carry significant morbidity and complication risks; such approaches are best reserved for cases with severe, disabling symptoms, progressive deformity, or global imbalance.

Patient Preferences and Expectations: Surgical decisions must consider patient quality of life, goals, psychological profile, and willingness to accept surgical risks or possible reoperation, with shared decision-making emphasized

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Natural History of Sporadic Cerebral Cavernous Malformations by Zabramski Classification: Hemorrhage Risk and Functional Outcomes Over 5 Years

Neurosurgery 98:376–383, 2026

This prospective cohort study examines sporadic cerebral cavernous malformations (CCMs) categorized by Zabramski MRI types I–IV, reporting lesion features, presentation, hemorrhage rates, and mRS outcomes over a mean follow-up of 4.7 years. Type I lesions had the highest symptomatic presentation, largest size, brainstem predominance, and elevated hemorrhage risks.

Functional outcomes improved for some patients, but Type I had the poorest outcomes. Severe symptomatic hemorrhage was the strongest predictor of sustained disability (mRS ≥3). Types III and IV had low hemorrhage rates and favorable prognoses, supporting conservative management and tailored follow-up imaging.

Zabramski Classification: Stratifies cerebral cavernous malformations (CCMs) into Types I–IV based on MRI features, which correlate with clinical presentation, hemorrhage risk, and functional outcomes.

Type I Lesions: Show the highest annual symptomatic hemorrhage (SH) rate (13.9%), a 5-year cumulative risk of 50.6%, are mostly symptomatic at presentation, often located in the brainstem, and have the poorest long-term functional outcomes (mRS ≥2 in 35.4% at last follow-up).

Type II and III Lesions: Exhibit lower annual hemorrhage rates (2.9% and 1.8%, respectively), more frequently present with seizures or focal neurological deficits rather than hemorrhage, and have better long-term functional outcomes (Type II: mRS ≥2 in 11.2%; Type III: mRS ≥2 in 7.5% at last follow-up).

Type IV Lesions: Are exclusively asymptomatic, detected incidentally, have no observed hemorrhagic events during follow-up, and show no functional impairment (no cases of mRS ≥2).

Severe Symptomatic Hemorrhage: Is the strongest independent predictor of poor functional outcome (mRS ≥3), outweighing lesion type, age, location, or surgical intervention in multivariate analysis (HR 10.88, P < .001).

Dynamic Lesion Evolution: Zabramski type can change over time, particularly for Type I lesions, highlighting the need for longitudinal imaging and dynamic risk assessment rather than reliance on a single timepoint classification.

Clinical Management Implications: Conservative management is appropriate for most Type III and IV lesions due to their benign natural history, while Type I lesions require closer monitoring and individualized intervention strategies due to higher risk.

Study Limitations: Small sample sizes for Types III and IV, potential MRI protocol variability, and single-center design may limit generalizability; multicenter studies are needed for broader validation.

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Reduced risk of shunt revision with adjustable valves: a populationbased cohort study over three decades

Acta Neurochirurgica (2026) 168:29

This population-based retrospective cohort study compares shunt revision rates in 809 idiopathic normal pressure hydrocephalus (iNPH) patients treated with adjustable versus fixed-pressure ventriculoperitoneal valves at Kuopio University Hospital from 1991 to 2023. The study findings indicate a significantly lower overall revision rate and fewer hydrodynamic failures with adjustable valves. Peritoneal catheter malposition and infection were the predominant causes of revision in the adjustable group.

The study provides detailed methods, valve types, follow-up durations, and statistical analyses. It discusses the study’s strengths, such as the use of comprehensive national registries, and limitations, including the retrospective design and shorter follow-up period for adjustable valves. The authors conclude that adjustable valves improve revision-free survival and recommend their use in iNPH despite their higher cost.

Adjustable shunt valves significantly reduce the risk of shunt revision surgeries in idiopathic normal pressure hydrocephalus (iNPH) patients compared to fixed-pressure valves (14% vs. 30% revision rate, p < .001).

Hydrodynamic failures (overdrainage and underdrainage) are much less common causes of revision in adjustable valve patients than in those with fixed-pressure valves.

Revision-free survival is better in iNPH patients with adjustable valves, with a lower hazard ratio for first revision (HR = 1.76 for fixed-pressure valves, p < 0.001).

Peritoneal catheter malposition is the most common cause of revision with adjustable valves, while shunt underdrainage is most common with fixed-pressure valves.

Multiple revisions are less frequent in the adjustable valve group (27% of revised patients) compared to the fixed-pressure group (32%).

No significant difference in revision risk was found between adjustable valves with and without a gravitational unit.

Clinical improvement is possible after well-timed shunt revision surgery, emphasizing the need for rapid detection of malfunctions.

Recommendation: Adjustable shunt valves are advised for iNPH patients, as they decrease revision rates and improve revision-free survival, justifying their higher cost.

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Hurting More Than Helping? Decompressive Craniectomy in Patients With Symptomatic Intracerebral Hemorrhage After Mechanical Thrombectomy in Acute Ischemic Stroke

Neurosurgery 98:345–357, 2026

This multicentre registry study evaluates whether decompressive craniectomy (DC) improves 90-day functional outcomes in patients who developed symptomatic intracerebral haemorrhage (sICH) following mechanical thrombectomy for anterior-circulation acute ischaemic stroke. Using multivariable regression and propensity-score matching from 464 STAR registry patients, the authors compare clinical characteristics, procedural variables and mRS outcomes between DC and non-DC groups.

Findings indicate poor overall recovery (14% mRS 0–3; 56% mortality). After adjustment and matching, DC was associated with a lower odds of acceptable functional outcome and no consistent mortality benefit with similar results in low-ASPECTS subgroups. This suggests limited functional gains from DC in this population.

Decompressive craniectomy (DC) after symptomatic intracerebral hemorrhage (sICH) following mechanical thrombectomy (MT) for acute ischemic stroke (AIS) is not associated with improved functional outcomes at 90 days; only 11% of DC patients achieved a modified Rankin Scale (mRS) of 0-3, compared to 15% without DC (adjusted odds ratio [OR] 0.2, 95% CI 0.02-0.9, P = .045).

Mortality rates at 90 days were similar between DC and non-DC groups after multivariable adjustment and propensity score matching, despite a lower crude mortality in the DC group in univariable analysis (DC: 43%, non-DC: 59%; adjusted P = .5).

Propensity score–matched analysis confirmed that patients undergoing DC had significantly lower odds of achieving an acceptable functional outcome (8% vs 24%, P = .045), with no significant mortality difference (P = .10).

Patients selected for DC were generally younger, more likely to be female, and had higher-grade hemorrhages (parenchymal hematoma type 2) compared to those not undergoing DC.

Subgroup analysis of patients with large infarct cores (ASPECTS <6) showed that DC was not associated with improved functional outcome or mortality, suggesting limited benefit in this population.

Overall prognosis for sICH after AIS treated with MT is poor, with only 14% of all patients achieving mRS 0-3 at 90 days and 56% mortality, regardless of DC.

Findings challenge previous smaller studies and recent guidelines suggesting benefit of DC in malignant MCA infarction or spontaneous sICH, highlighting the unique poor prognosis in post-MT sICH.

Study limitations include retrospective design, lack of standardization in DC decision-making, missing imaging data, and potential selection bias, which could influence the observed associations.

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The Role of Intraoperative Imaging Modalities in Surgical Resection of Supratentorial Gliomas: A Review of 300 Cases

Operative Neurosurgery 30:278–288, 2026

This retrospective study of 300 supratentorial glioma surgeries compares outcomes using intraoperative MRI (iMRI), navigated intraoperative ultrasound (iUS) and no intraoperative imaging. It reports higher gross total resection rates and greater contrast-enhancement extent with iMRI and iUS, with iMRI achieving the highest contrast-enhanced extent of resection (CE-EOR) but longer operative times.

Clinical outcomes show fewer postoperative weaknesses and better overall survival when intraoperative imaging is used. Postoperative cognitive and sensory deficits varied by modality; progression-free survival differences were not significant. Study limitations include a retrospective design, the temporal rollout of modalities and differing surgeon experience.

Gross Total Resection (GTR) Rates: GTR was significantly more common with intraoperative MRI (iMRI, 56.9%) and intraoperative ultrasound (iUS, 57.1%) than without intraoperative imaging guidance (34%) in glioma surgery.

Extent of Resection (EOR): The mean EOR of contrast enhancement was highest with iMRI (96.6%), followed by iUS (93.2%), and lowest without intraoperative imaging (92%).

Postoperative Neurological Deficits: Patients without intraoperative imaging had significantly higher rates of postoperative weakness compared to those with iMRI or iUS (odds ratio = 0.520, CI = 0.272-0.994, P = .048).

Overall Survival (OS): Overall survival was significantly worse in patients without intraoperative imaging guidance (odds ratio = 1.534, CI = 1.058-2.225, P = .024) than in those with iMRI or iUS.

Progression-Free Survival (PFS): No significant differences in progression-free survival were found between the subgroups using iMRI, iUS, or no intraoperative imaging.

Surgery Duration: Mean surgery duration was longest with iMRI (260 minutes), intermediate with iUS (194 minutes), and shortest without intraoperative imaging (175 minutes).

Postoperative Functional Status: Karnofsky Performance Status (KPS) at 1 year was lowest in patients without intraoperative imaging guidance, indicating worse functional outcomes.

Study Limitations: The retrospective design, differing periods of iMRI and iUS use, learning curves, and unequal subgroup sizes limit the ability to fully compare all factors and may affect recurrence rate assessments.

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Percutaneous modified iliac screw fixation: technique and clinical experience

Acta Neurochirurgica (2026) 168:20

This study reports clinical experience with a percutaneous modified iliac screw (PMIS) technique for sacropelvic fixation, developed to reduce soft-tissue dissection and avoid limitations of conventional iliac and S2 alar-iliac screws. Ten patients treated between 2014 and 2025 for mainly metastatic spinal disease underwent PMIS under C-arm fluoroscopy with virtual reference lines guiding intra-iliac cancellous screw placement.

Outcomes showed no wound infections, screw prominence complaints, sciatic notch or acetabular violations, or radiographic loosening (except one case requiring removal for progressing infection unrelated to PMIS). Spinopelvic alignment remained stable, and authors conclude PMIS is a safe, minimally invasive alternative warranting larger studies for broader validation.

Percutaneous Modified Iliac Screw (PMIS) Technique: PMIS is a minimally invasive method for sacropelvic fixation that uses fluoroscopic guidance and virtual reference lines to safely insert screws into the intra-iliac cancellous corridor, aiming to overcome drawbacks of conventional iliac screw (CIS) and S2 alar-iliac (S2AI) techniques.

Clinical Outcomes: In a retrospective series of 10 patients, PMIS showed no cases of infection, screw prominence, or screw-related complications, with only one revision required due to unrelated infection progression.

Spinopelvic Stability: Radiographic evaluation demonstrated that spinopelvic parameters (pelvic incidence, pelvic tilt, sacral slope) remained stable from preoperative to final follow-up, indicating maintenance of alignment.

Advantages Over Traditional Methods: PMIS avoids the need for offset connectors, reduces soft tissue dissection, minimizes screw head prominence, and potentially lowers infection and wound complication rates compared to CIS and S2AI methods.

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A Scoping Review of Focused Ultrasound- Blood-Brain Barrier Opening for Treatment of Chronic Pain

Neurosurgery 98:328–338, 2026

This scoping review evaluates focused ultrasound–mediated blood–brain barrier opening (FUS‑BBBO) as a targeted drug‑delivery strategy to treat chronic pain, summarizing systematic literature screening and preclinical evidence. It outlines how FUS parameters, microbubbles, and regional targeting can transiently permit delivery of drugs and particles otherwise excluded by the BBB, potentially improving efficacy and reducing systemic toxicity.

The document surveys candidate therapeutics (opioids, peptides, antibodies, gene therapies) and particle vehicles (nanoparticles, liposomes, niosomes, AAVs), highlights preclinical successes and delivery challenges, and stresses safety, parameter optimization, and the need for human trials. It concludes that FUS‑BBBO combined with advanced delivery platforms holds promise but requires systematic clinical evaluation.

Blood-brain barrier (BBB) challenge: The BBB restricts most drugs from entering the brain, impeding effective pharmacological treatment of chronic pain, with only small, lipophilic molecules (<400–500 Da) able to cross easily, while 98% of small molecules and nearly all large molecules are excluded.

Focused ultrasound (FUS)-mediated BBB opening (FUSBO): FUSBO uses low-intensity ultrasound and microbubbles to temporarily, noninvasively open the BBB, enabling targeted drug delivery to specific brain regions without thermal damage.

Current pain therapies’ limitations: Opioids, gabapentin, cannabinoids, and other agents have limited efficacy and significant systemic side effects due to poor BBB penetration and susceptibility to efflux mechanisms like p-glycoprotein pumps.

Preclinical evidence, lack of human trials: While FUSBO has shown success in animal models for delivering pain therapies directly to the CNS and enhancing efficacy, no human studies have yet assessed FUSBO for chronic pain treatment.

Advancements in drug delivery particles: Nanoparticles, niosomes, polymeric nanoparticles, gold nanoparticles, and liposomes can be engineered to carry drugs across the BBB, improve bioavailability, and reduce toxicity, especially when combined with FUSBO.

Potential for biologics and gene therapy: FUSBO may enable delivery of monoclonal antibodies, single-chain fragment variable antibodies, and adeno-associated virus (AAV) gene therapies to the CNS, overcoming size and immune barriers.

Safety and technical considerations: FUSBO is generally safe in animal and early human studies, but potential risks include microglial activation, microhemorrhage, and neuronal suppression at high intensities; optimal parameters for various drugs and delivery systems remain to be established.

Outlook and clinical promise: FUSBO combined with advanced drug delivery particles could transform chronic pain management by bypassing the BBB, expanding the range of usable therapies, and improving the therapeutic window, but clinical trials are needed to confirm efficacy and safety in humans.

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Deep brain stimulation for obsessive-compulsive disorder: evolution of tractography-based targeting

J Neurosurg 144:293–304, 2026

This clinical study describes the development and prospective application of patient-specific tractography to refine anterior limb of the internal capsule (ALIC) deep brain stimulation (DBS) targeting for treatment-refractory obsessive-compulsive disorder (OCD). The authors generated a common responder connectivity map highlighting ALIC pathways to vmPFC/OFC, vlPFC, thalamus, STN, and midbrain, then used that map to guide implantation in a new cohort, achieving consistent and rapid Y-BOCS improvements.

The team also built a tractography-based stimulation model linking activation of specific unilateral ALIC pathways to symptom reduction, demonstrating selective prediction of obsessive–compulsive symptom improvement (but not mood or anxiety). Results suggest that tractography-guided “sweet spot” targeting at the ventral ALIC near the GPe can reduce trial-and-error programming and support precision ALIC DBS implementation.

Patient-specific tractography targeting: Using individualized diffusion MRI tractography to guide deep brain stimulation (DBS) lead placement in the anterior limb of the internal capsule (ALIC) for obsessive-compulsive disorder (OCD) enables more precise and consistent targeting of therapeutic white matter pathways.

Common responder map: A map of white matter connections shared by DBS responders was generated, highlighting key pathways to the ventromedial/orbitofrontal cortex (vmPFC/OFC), ventrolateral prefrontal cortex (vlPFC), and midbrain; targeting this “sweet spot” led to improved and predictable clinical outcomes.

Improved clinical efficacy: Tractography-based ALIC DBS resulted in an 80% response rate (≥35% Y-BOCS reduction) among prospective patients, with faster and more consistent OCD symptom improvement compared to prior methods.

Reduced trial-and-error programming: Targeting based on the common responder map minimized the need for multiple adjustments in stimulation parameters, streamlining clinical implementation.

Symptom specificity: Stimulation of the tractography-defined target selectively improved OCD symptoms (obsessions and compulsions) with less impact on mood or anxiety and minimal side effects such as hypomania.

Tractography-based predictive model: A quantitative model using patient-specific pathway activation predicted OCD symptom improvement (Y-BOCS reduction), with strongest predictive value for connections to vlPFC, vmPFC/OFC, thalamus, and midbrain, but not for depression or anxiety scores.

Updated common responder map validation: High-resolution 7T MRI data from additional responders confirmed the importance of connections to vlPFC, vmPFC/OFC, thalamus, and midbrain in therapeutic response.

Potential for clinical scalability: This precision targeting approach, if validated in larger cohorts, could enhance the predictability, effectiveness, and broader adoption of DBS for treatment-resistant OCD.

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Resectability of spheno-orbital meningiomas: surgical outcome in 93 cases and a proposed clinically relevant anatomical classification

J Neurosurg 144:336–345, 2026

This clinical study evaluates surgical outcomes for 93 patients with spheno-orbital meningiomas (SOMs) treated over two decades, proposing a four-grade anatomical classification based on orbital involvement. The paper reports presentation patterns, operative techniques, extent of resection, proptosis quantification with an exophthalmos index, and postoperative visual and surgical morbidity rates.

Using retrospective imaging and clinical data, the authors validate the grading system’s predictive value for resectability, proptosis improvement, and visual risk, showing higher gross-total resection rates in lower-grade tumors and substantial vision stabilization or improvement across grades. The work offers practical guidance for surgical planning and patient counseling in complex skull-base and orbital tumor management.

Anatomical Grading System: SOMs are classified into four grades based on orbital involvement: grade 1 (orbital hyperostosis), grade 2 (periorbital involvement), grade 3a/b (intraorbital involvement without/with rectus muscle invasion), and grade 4 (involvement of the orbital apex or optic nerve).

Surgical Resectability: Gross-total resection (GTR) is most achievable in grade 1 (88.5%) and decreases with higher grades (grade 2: 50.0%, grade 3: 16.7%, grade 4: 24.1%), primarily limited by critical neurovascular structures and functional vision considerations.

Presenting Symptoms: Proptosis (74.2%) and visual decline (57.0%) are the most common symptoms, with higher-grade tumors more likely to present with proptosis, vision loss, and cranial neuropathies.

Visual Outcomes: Surgery led to stable or improved vision in nearly 95% of patients across all grades, with no significant difference in visual morbidity between low- and high-grade tumors.

Proptosis Improvement: Correction of proptosis was most significant in grades 2 and 4, with overall exophthalmos index (EI) significantly decreasing after surgery; clinically significant enophthalmos was rare.

Surgical Morbidity: Overall morbidity increased with higher tumor grade but was not statistically significant; new ophthalmological cranial nerve neuropathies occurred in 11.8% of patients.

Surgical Approach: Aggressive removal of tumor and hyperostotic bone, with selective intraorbital dissection, optimizes functional outcomes and proptosis reduction; rigid orbital reconstruction is generally not required.

Clinical Utility: The grading system aids in predicting surgical risks, visual outcomes, and in guiding patient counseling and surgical planning for SOMs.

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Single-Session Middle Meningeal Artery Embolization With Concomitant Evacuation Surgery for Chronic Subdural Hematomas: A Multicenter Assessment of Feasibility, Safety, and Efficacy

Operative Neurosurgery 30:270–277, 2026

This multicenter retrospective cohort assesses feasibility, safety, and short-term efficacy of performing middle meningeal artery embolization (MMAE) concurrently with surgical evacuation for chronic subdural hematoma in a single anesthetic session. Among 157 patients, technical success was 97.4%, radiographic improvement occurred in 91.7%, and 63.1% achieved ≥50% hematoma reduction, with a 10.8% overall complication rate and 0.6% procedure-related mortality.

The report compares outcomes to recent randomized trials and existing series, noting similar intraprocedural complication rates and favorable reintervention and functional-independence outcomes (83.9% mRS ≤2 at median 54 days). Authors highlight potential resource and LOS advantages, acknowledge retrospective limitations, and call for prospective studies to define long-term benefit, cost impact, and selection criteria.

Single-session MMAE plus evacuation: Performing middle meningeal artery embolization (MMAE) and surgical evacuation for chronic subdural hematoma (cSDH) in a single anesthetic session is feasible and technically successful in 97.4% of cases, with no major intraprocedural failures reported.

Safety profile: The overall complication rate for the combined procedure is 10.8%, with a low intraprocedural complication rate of 2.5% and a procedure-related mortality of 0.6%, comparable to or better than staged approaches and recent randomized trials.

Radiographic and functional outcomes: Radiographic improvement is observed in 91.7% of patients, with 63.1% achieving at least a 50% reduction in hematoma thickness; 83.9% of patients maintain or achieve functional independence (mRS ≤2) at short-term follow-up.

Hospital length of stay (LOS): The median hospital LOS is 6 days, which is slightly shorter than reported in comparable studies using staged procedures, suggesting potential for reduced resource utilization.

Reintervention rates: Unplanned reoperations during the index hospitalization are low (2.5%), including for recurrent hematomas and subdural empyema, which favorably compares to other large studies and randomized trials.

Patient selection and anesthesia: Most procedures use general anesthesia (92%), but monitored anesthesia care (MAC) or conscious sedation may further streamline care in selected patients and reduce anesthesia-related risks.

Applicability to complex cases: The single-session approach is effective and safe even in patients with bilateral cSDH, who are often considered more complex.

Future directions: Prospective studies are needed to assess long-term outcomes, cost-effectiveness, ideal patient selection, and whether this approach reduces recurrence and enhances recovery compared to staged strategies.

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Added Value of Adjunctive Middle Meningeal Embolization to Surgical Evacuation for Chronic Subdural Hematoma: Comprehensive Meta-Analysis Based on Controlling Confounders

Neurosurgery 98:303–317, 2026

This meta-analysis evaluates whether adding middle meningeal artery embolization (MMAE) to surgical evacuation improves outcomes in patients with chronic subdural hematoma (CSDH).

Key Insights and Themes

Chronic subdural hematoma (CSDH) is a common neurological disorder with high recurrence rates after surgical evacuation, ranging from 2% to 37%.

Middle meningeal artery embolization (MMAE) has emerged as an adjunct or alternative to surgery, aiming to reduce CSDH recurrence by targeting the vascular supply of the hematoma membranes.

Systematic review and meta-analysis included 17 studies (1814 patients; 939 MMAE+S, 1440 S), comprising randomized trials, matched, and unmatched cohorts, with a mean follow-up of 3 months.

Baseline comparability between MMAE+S and surgery-alone groups was achieved except for higher antithrombotic use in the MMAE+S group (34.9% vs 22.4%).

Recurrence rates were significantly lower in the MMAE+S group compared to surgery alone (4.7% vs 17.7%; relative risk [RR] 0.31, P < .01), a benefit confirmed in randomized and matched studies.

Radiological outcomes (postoperative hematoma thickness, volume, and midline shift) were all significantly reduced in the MMAE+S group.

Functional outcomes, complications, mortality, and hospital stay were similar between groups, indicating no increased risk with adjunctive MMAE.

Timing of embolization affected outcomes: postoperative MMAE was associated with lower recurrence, while preoperative MMAE did not show significant benefit.

Embolic agent selection mattered: liquid embolic agents (e.g., Onyx, Squid) led to better outcomes than particles, with recurrence reduction seen only with liquid agents.

Antithrombotic use, a known risk factor for recurrence, was higher in the MMAE+S group, yet recurrence rates remained lower, suggesting a robust effect of adjunctive MMAE.

Surgical technique variability (burr-hole craniostomy, craniotomy, twist-drill) existed across studies, potentially influencing heterogeneity in outcomes.

Complication rates were low and comparable between groups; most complications were minor, and serious adverse events were rare.

Length of hospital stay did not differ significantly between groups, though some previous studies suggested longer stays with MMAE+S, possibly due to worse initial clinical status.

Cost-effectiveness may favor MMAE+S in the long term, as reduced recurrence and reoperation rates can offset higher initial costs.

Ongoing clinical trials (e.g., CHESS, MEMBRANE, EMPROTECT) are expected to clarify optimal timing, patient selection, and cost-effectiveness of adjunctive MMAE.

Limitations include heterogeneity in surgical and embolization techniques, retrospective study designs, and reliance on aggregate rather than individual patient data.

Areas for future research include optimal timing and materials for MMAE, patient selection, and cost-benefit analyses.

Conclusion

Adjunctive MMAE with surgical evacuation significantly reduces CSDH recurrence and improves radiological outcomes without increasing complications or mortality, supporting its use in high-risk patients.

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