Author: cba

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Sarcopenia Predicts Early Adjacent Segment Disease Development After Anterior and Oblique Lumbar Interbody Fusion

Operative Neurosurgery 29:667–677, 2025

his clinical study evaluates whether sarcopenia, measured by psoas-to-vertebral body morphometrics on preoperative MRI, predicts early adjacent segment disease (ASD) within three years after anterior or oblique lumbar interbody fusion (ALIF/OLIF). Retrospective analysis of 104 patients found sarcopenia strongly associated with ASD, with sarcopenic patients showing markedly higher ASD rates and greater muscle fat infiltration.

The paper reports that psoas area, P:VBR ratios, and age remained significant predictors on multivariate analysis, while spinopelvic parameters lost significance after adjustment. The authors propose routine preoperative morphometric screening to guide surgical planning, risk counseling, and targeted perioperative optimization for high-risk patients.

• Sarcopenia: Preoperative sarcopenia, defined by reduced psoas muscle area relative to vertebral body area, is a strong independent predictor of early adjacent segment disease (ASD) within 3 years after anterior or oblique lumbar interbody fusion (ALIF/OLIF) ().

• ASD Incidence: 24% of patients developed ASD within 3 years post-ALIF/OLIF; 84.21% of sarcopenic patients developed ASD compared to 10.59% of nonsarcopenic patients.

• Morphometric Assessment: Psoas:vertebral body ratio (P:VBR) at L4 on preoperative MRI provides a simple, objective screening tool for sarcopenia and ASD risk stratification.

• Spinopelvic Parameters: Postoperative pelvic tilt (PT) and pelvic incidence-lumbar lordosis (PI-LL) mismatch were associated with ASD in univariate analysis, but not after multivariate adjustment; sarcopenia remained the strongest predictor.

• Other Risk Factors: Older age, higher preoperative disability (ODI), more instrumented/interbody levels, and prior lumbar surgery also increased ASD risk, while gender, BMI, and comorbidities did not.

• Instrumentation vs. Stand-alone Cages: Patients with stand-alone ALIF/OLIF (no posterior instrumentation) had lower rates of ASD, possibly due to less mechanical stress on adjacent segments.

• Clinical Implications: Identifying sarcopenia preoperatively can inform surgical planning, patient counseling, and may guide targeted pre- and postoperative interventions to improve outcome.

• Future Directions: Further research is needed to determine if interventions like resistance training or dietary modification can reduce ASD risk in sarcopenic patients, and to establish standardized diagnostic criteria for sarcopenia in spine surgery.

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Does the Presence of Preoperative Myelomalacia Impact Outcomes Following ACDF?

Spine 2025;50:1539–1546

This retrospective cohort study examines whether preoperative cervical myelomalacia on MRI influences patient-reported outcomes after anterior cervical discectomy and fusion (ACDF) in 518 adults. Results show similar modified JOA (mJOA) recovery between groups, with myelomalacia not independently predicting worse mJOA up to one year postoperatively.

Secondary findings reveal myelomalacia patients had lower baseline pain/disability and less frequent NDI MCID achievement, but multivariable analysis attributed those differences to baseline scores, smoking, and demographics rather than myelomalacia itself. Multilevel myelomalacia correlated with worse baseline mJOA but did not independently affect long-term improvement.

• Preoperative Myelomalacia: Presence of myelomalacia on MRI before anterior cervical discectomy and fusion (ACDF) in patients with mild-moderate myelopathy does not predict worse postoperative mJOA scores or overall patient-reported outcomes at any time point up to one year after surgery.

• Functional Outcomes: Both patients with and without preoperative myelomalacia achieve similar improvements in functional outcomes (mJOA), with no significant difference in the likelihood of reaching the minimum clinically important difference (MCID) for mJOA.

• Neck Disability Index (NDI): Patients with myelomalacia less commonly achieve MCID for NDI at one year, but this is attributable to less severe baseline symptoms and higher rates of current smoking, not the presence of myelomalacia itself.

• Multilevel Myelomalacia: Patients with two or more levels of myelomalacia have worse preoperative mJOA scores but show greater short-term improvement, resulting in similar one-year outcomes compared to single-level myelomalacia; preoperative severity, not the extent of myelomalacia, predicts improvement.

• Baseline Differences: Patients with myelomalacia tend to have lower baseline pain and disability, possibly due to earlier surgical intervention prompted by MRI findings rather than symptom severity.

• Other Patient-Reported Outcomes: Myelomalacia patients may have better physical component scores (SF-12 PCS) and lower neck pain (VAS neck) at one year, but these differences are small and likely reflect baseline characteristics rather than effects of myelomalacia.

• Prognostic Value: Myelomalacia seen on MRI should not be used as a binary prognostic indicator for surgical outcomes in mild-moderate myelopathy; clinical decision-making should consider baseline function and other patient factors.

• Research Implications: Further studies are needed to clarify the impact of myelomalacia severity, chronicity, and timing on outcomes, especially in patients with more severe myelopathy or more extensive cord signal changes

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Awake surgery for IDH-mutant grade 2 glioma involving the corpus callosum: long-term onco-functional results after callosectomy in 157 consecutive patients

J Neurosurg 143:1280–1289, 2025

This clinical study reports outcomes from 157 consecutive patients with IDH‑mutant grade 2 gliomas infiltrating the corpus callosum who underwent connectome-guided awake surgery with callosectomy. It summarizes surgical technique, extent of resection, complication rates, return-to-work statistics, histology, adjuvant treatments, reoperations, and long-term overall survival.

Comparative analysis contrasts complete (total/supratotal) versus incomplete resections, showing higher extent of resection, greater reoperation potential, and longer median overall survival when callosal tumor was fully removed, while preserved function and a 96.8% return-to-work rate underline favorable onco-functional balance.

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Evaluating longitudinal changes of gait parameters following shunt placement in patients with idiopathic normal pressure hydrocephalus

J Neurosurg 143:1254–1261, 2025

This clinical study evaluates objective, longitudinal gait changes in 212 patients with idiopathic normal pressure hydrocephalus (iNPH) following ventriculoperitoneal shunt (VPS) placement, using serial instrumented motion analysis over a median 12-month follow-up. Short-term analyses show significant improvements in all measured gait metrics within three months, with gait velocity, stride length, and stability ratio demonstrating the largest gains.

Longitudinal modeling with generalized additive mixed-effects models reveals that improvements in velocity, stride length, and single support emerge early and plateau around six months, while cadence changes are minimal until later follow-up. The authors note persistent but incomplete recovery relative to healthy norms, discuss methodological limitations, and call for multicenter prospective studies linking objective gait metrics to patient-reported outcomes.

• Idiopathic Normal Pressure Hydrocephalus (iNPH) Characteristics: iNPH is marked by progressive gait disturbance, cognitive impairment, and urinary incontinence, with gait abnormalities increasing fall risk and often presenting as shuffling, short stride, and instability.

• Ventriculoperitoneal Shunt (VPS) Treatment: VPS placement is the standard of care for iNPH, aiming to improve symptoms by diverting cerebrospinal fluid (CSF) after confirmation of shunt responsiveness via CSF tap test.

• Objective Gait Assessment: Gait parameters—including velocity, cadence, stride length, step width, stability ratio, and support phases—were measured using a pressure-sensitive walkway before and at multiple intervals after VPS placement.

• Short-Term Gait Improvements: Statistically significant improvements in all gait parameters were observed within 3 months post-VPS, with the greatest changes in gait velocity (+27%), stride length (+17.5%), and gait stability ratio (−14.1%).

• Longitudinal Gait Outcomes: Improvements in gait velocity, stride length, and single support phase continued up to 6 months post-surgery, then plateaued and persisted through 24 months, although not reaching normative values seen in healthy controls.

• Majority of Patients Benefit: Over 80% of patients experienced improvement in most gait parameters, with durable benefits maintained through long-term follow-up.

• Limitations: The study’s retrospective, single-center design and specialized gait analysis setup may limit generalizability; potential biases include loss to follow-up and lack of control for comorbidities.

• Clinical Implication: Objective gait analysis validates durable improvement after VPS in iNPH, supporting its use for monitoring surgical outcomes and informing patient care.

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Machine Learning–Based Rupture Risk Prediction for Intracranial Aneurysms: A Systematic Review and Meta-Analysis

Neurosurgery 97:1072–1082, 2025

This systematic review and meta-analysis evaluates machine learning (ML) applications for predicting intracranial aneurysm rupture, comparing 124 ML models across 36 retrospective studies (22,462 patients) with the PHASES score. Results show ML—especially deep learning and SVM—achieves higher AUC and specificity than PHASES, with hemodynamic inputs improving test-set specificity but not external validation.

The authors highlight methodological heterogeneity, risks of bias, and overfitting concerns from retrospective single‑center data, urging prospective, standardized studies and external validation before clinical integration of ML rupture‑risk tools.

Machine Learning (ML) Models: ML techniques, including deep learning (DL), support vector machines (SVM), and regression models, show higher specificity and overall diagnostic accuracy than the traditional PHASES score for predicting intracranial aneurysm rupture risk, with comparable sensitivity.

• Deep Learning Performance: DL models achieved the highest sensitivity (up to 0.87), specificity (up to 0.86), and area under the curve (AUC-ROC up to 0.92) among all ML families, indicating strong discriminative ability in rupture risk prediction.

• PHASES Score Limitations: The PHASES score, though widely used, demonstrates lower specificity (0.51) and modest overall discriminative ability (AUC-ROC 0.66), and does not incorporate important risk factors like aneurysm morphology or family history.

• Hemodynamic Parameters: Incorporating hemodynamic variables (e.g., wall shear stress, flow patterns) into ML models improves specificity and accuracy in test sets, but benefits are less pronounced in external validation, possibly due to sample size and generalizability issues.

• Retrospective Data and Overfitting: All included ML models were trained on retrospective, post-rupture data, raising concerns about overfitting and the applicability of these models to pre-rupture clinical decision-making.

• Generalizability Concerns: ML models often perform less well on external validation data due to biases in patient selection, single-center data, and differences in imaging or clinical protocols, while the PHASES score maintains more consistent performance across settings.

• Need for Prospective Validation: There is a critical need for prospective studies and standardized protocols to confirm the clinical utility and reliability of ML-based rupture risk prediction models before integration into routine practice.

• Clinical Implications: ML approaches, especially DL and SVM, have the potential to enhance individualized risk stratification and reduce overtreatment, but methodological challenges and validation in diverse populations remain essential for safe clinical adoption.

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Afferent and efferent fiber systems of the human amygdala: anatomical, pathophysiological, and clinical significance

J Neurosurg 143:1202–1216, 2025

This paper presents a comprehensive neuroanatomical and radiological analysis of the human amygdala, detailing its nuclei, major afferent and efferent fiber systems, and spatial relationships using white matter fiber dissection and diffusion tensor tractography. The authors synthesize structural descriptions with functional roles in emotion, memory, olfaction, and seizure propagation, emphasizing clinical relevance for neuroclinicians.

The study maps key pathways—the ansa peduncularis, ventral and dorsal amygdalofugal routes, stria terminalis, medial forebrain bundle, olfactory striae, and stria medullaris thalami—correlating anatomy with neurosurgical applications such as deep brain stimulation and lesion resection. Anatomical findings are supported by illustrative dissections, tractography, and a clinical cavernoma case demonstrating surgical implications.

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Comparison of Sagittal Plane Correction With “Bullet” Versus “Banana” Type Transforaminal Lumbar Interbody Fusion Devices

Operative Neurosurgery 29:624–632, 2025

This clinical study evaluates whether “Banana” versus “Bullet” transforaminal lumbar interbody fusion (TLIF) devices produce different immediate postoperative segmental lordosis in one- and two-level degenerative lumbar fusions. Using 241 treated levels from 198 patients, the authors compare radiographic outcomes and perform multivariable regression to identify independent predictors of postoperative segmental lordosis and its change.

Findings show univariable advantages for “Banana” cages in small magnitudes, but multivariable analysis identifies preoperative segmental lordosis, implant-listed lordosis, pelvic incidence, and use of bilateral TLIF windows—not cage morphology—as primary predictors of immediate postoperative segmental correction. The paper recommends further work on subsidence risk and maintenance of correction.

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Five-year follow-up after minimally invasive transforaminal lumbar interbody fusion versus decompression alone for grade 1 spondylolisthesis: are there any differences in outcomes?

J Neurosurg Spine 43:547–556, 2025

This multicenter, prospective registry study compares 60-month outcomes after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) versus minimally invasive tubular decompression for Meyerding grade 1 degenerative spondylolisthesis. Patient-reported outcomes (ODI, NRS for back/leg pain, EQ-5D, NASS satisfaction) improved significantly in both cohorts, with MIS TLIF showing greater back-pain reduction and higher satisfaction rates.

Durability differs: MIS TLIF had a markedly lower 5-year reoperation rate than MIS decompression (2.8% vs 15.5%), and multivariable analysis found fusion reduced reoperation odds despite similar long-term PROs. Authors conclude both MIS approaches benefit selected patients, but fusion offers superior reoperation durability.

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Brain Bleeding Associated With Cavitation During Focused Ultrasound Ablation

Neurosurgery 97:1215–1218, 2025

This report presents two cases of symptomatic intracranial hemorrhage occurring during MR-guided focused ultrasound (MRgFUS) ablation for movement disorders, associated with persistent cavitation activity despite power reductions. Both patients developed contralateral motor deficits after sonications; one recovered substantially, the other remained significantly disabled, and imaging confirmed hematomas at the targeted sites.

The authors review procedural variables, cavitation mechanisms, mitigation strategies, and institutional experience (~500 cases, 0.4% incidence), recommending a conservative approach—including treatment termination—when uncontrollable cavitation arises, and urging further study of patient- and system-related risk factors to minimize bleeding risk.

• MRgFUS Complication: Symptomatic brain bleeding can occur during magnetic resonance–guided focused ultrasound (MRgFUS) ablation for movement disorders, although it is a rare complication (approximately 0.4% incidence in a center with over 500 cases).

• Cavitation Risk: Persistent cavitation—microbubble formation and collapse during sonication—is strongly associated with the occurrence of brain hemorrhage in MRgFUS procedures, even when standard mitigation steps (such as lowering power) are taken.

• Case Outcomes: In two reported cases, both patients developed contralateral motor weakness and brain hematoma following persistent cavitation during MRgFUS; one patient recovered functional independence, while the other remained severely disabled.

• Technical Mitigation: When cavitation is detected, the recommended strategy is to reduce sonication power and, if needed, increase duration to maintain energy delivery; however, if uncontrollable cavitation persists, treatment termination should be considered.

• Patient Factors: Bleeding can occur even in patients without traditional vascular risk factors, suggesting procedural factors like cavitation may be more critical than patient comorbidities in these cases.

• Incidence and Reporting: Over 20,000 MRgFUS procedures have been performed globally with very few reports of symptomatic brain bleeding, highlighting the importance of continued reporting to refine safety practices.

• Clinical Implication: MRgFUS is an effective and generally safe treatment for movement disorders, but it is not without risk; both clinicians and patients should be aware that severe complications, though rare, are possible.

• Best Practice: A conservative approach is advised if cavitation cannot be controlled during MRgFUS, and further study into both technical and patient-related risk factors for hemorrhage is warranted.

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Sixto Obrador (1911–1978), Spain’s father of neurosurgery: his quest to raise its practice to world-class scientific standards

J Neurosurg 143:1137–1148, 2025

Sixto Obrador Alcalde (1911–1978) is profiled as the architect of modern scientific neurosurgery in Spain, tracing his international training, prolific surgical career, and institutional leadership. The article documents his return from Anglo‑American mentorships to build neurosurgical departments, perform over 5,000 intracranial tumor surgeries, and publish extensively, emphasizing rigorous scientific practice and resident research training.

The paper reviews Obrador’s organizational achievements: founding Spanish neurosurgical units, cofounding SLEN, contributing to WFNS and EANS, and helping establish referral hospitals integrating clinical and basic neuroscience. It highlights his commitment to education, multidisciplinary collaboration, and translating Cajal’s scientific legacy into a national neurosurgical standard.

• Pioneer of Spanish Neurosurgery: Sixto Obrador (1911–1978) established neurosurgery as a distinct specialty in Spain, raising its scientific and clinical standards to international levels despite the country’s postwar hardships and late start due to the Spanish Civil War.

• Influence of the Cajal School: Obrador revived the scientific legacy of Santiago Ramón y Cajal and Pío del Río-Hortega, integrating neuropathology and neurophysiology into neurosurgical practice and emphasizing research as a core component of training.

• International Training and Mentorship: He received extensive training in neurophysiology and neurosurgery in the UK, US, and Mexico under renowned figures like Charles Sherrington, Hugh Cairns, Norman Dott, and John Fulton, which shaped his scientific approach.

• Institution Building: Obrador founded and organized several leading neurosurgical departments and hospitals in Madrid, including the first Institute of Neurosurgery, La Princesa Hospital, Fundación Jiménez Diaz, La Paz Hospital, and the Ramón y Cajal Hospital.

• Surgical and Scientific Output: He performed over 5,000 brain tumor surgeries, published more than 400 scientific papers, and authored Spain’s first neurosurgery textbook, establishing benchmarks for surgical outcomes and research in the field.

• Advances in Neurosurgical Techniques: Obrador introduced and developed techniques such as the first successful hemispherectomy in Europe, stereotactic procedures for movement disorders, and the use of intraoperative hypothermia, contributing to reduced mortality rates.

• Professional Leadership and International Collaboration: He co-founded the Portuguese-Spanish Society of Neurosurgery (SLEN), played key roles in the World Federation of Neurosurgical Societies (WFNS) and the European Association of Neurosurgical Societies (EANS), and promoted Spanish neurosurgery internationally.

• Legacy in Education and Research: Obrador’s main legacy is the integration of scientific research and multidisciplinary training in Spanish neurosurgery, influencing generations of neurosurgeons and establishing Spain as a respected center for neurosurgical excellence.

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Comparative effectiveness of standalone middle meningeal artery embolization versus surgical evacuation in noncritical patients with nonacute subdural hematomas

Neurosurg Focus 59(4):E8, 2025

This retrospective propensity score–matched cohort study compares standalone middle meningeal artery embolization (sMMAE) with standard surgical evacuation for nonacute subdural hematomas (NASDH) in noncritical patients treated from 2017–2024. Primary outcome was reintervention for recurrence; secondary outcomes included hospital length of stay (LOS), new neurological deficits, and adverse events.

After matching 85 patients per group, reintervention rates did not differ significantly (IRR 1.38, p=0.41). sMMAE was associated with shorter median LOS (4 vs 6 days, p=0.003) and fewer noncardiorespiratory medical adverse events, suggesting sMMAE may be a less-invasive option in selected patients while larger trials are needed.

• Standalone Middle Meningeal Artery Embolization (sMMAE) vs. Surgery: sMMAE for nonacute subdural hematoma (NASDH) showed no significant difference in reintervention rates due to hematoma recurrence compared to surgical evacuation (incidence rate ratio [IRR] 1.38, p = 0.41).

• Hospital Length of Stay: Patients treated with sMMAE had a significantly shorter hospital stay (median 4 days) compared to those who underwent surgical evacuation (median 6 days, p = 0.003).

• Adverse Events: sMMAE was associated with a lower risk of other medical (non-neurological, non-cardiorespiratory) adverse events (1.1% vs 15.2%; relative risk [RR] 0.07, p = 0.013), with no significant differences in new neurological deficits or cardiorespiratory/neurological adverse events between groups.

• Patient Selection: The findings apply to noncritical NASDH patients (midline shift < 10 mm, no coma) who are eligible for either intervention; results do not extend to patients with larger or rapidly deteriorating hematomas.

• Propensity Score Matching: Groups were balanced for key confounders (age, sex, comorbidities, hematoma characteristics) using propensity score matching, enhancing comparability of outcomes.

• Mortality: Mortality rates during follow-up were similar between groups and deaths were unrelated to the primary outcome of recurrence.

• Study Limitations: Limitations include retrospective design, moderate sample size, incomplete long-term clinical outcome data, and potential residual confounding by indication or procedural heterogeneity.

• Clinical Implication: sMMAE may offer a less invasive alternative to surgery with shorter hospitalization and fewer medical complications for selected NASDH patients, but larger studies are needed to confirm noninferiority and guide patient selection.

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Microsurgical anatomy of the fiber tracts and vascular structures lateral to the internal capsule

J Neurosurg 143:1068–1076, 2025

This microsurgical study maps white matter fiber tracts and vascular anatomy from the brain’s lateral surface to the internal capsule using perfused cadaveric specimens and Klingler fiber dissection. Key tracts (AF, SLF II/III, FAT, MdLF, UF, IFOF) and vascular elements (MCA segments, LSAs, LSVs, venous drainage groups) are described with measurements and surgical landmarks.

Findings emphasize trajectories relevant to Kocher’s point, the spatial relationships of LSAs/LSVs to the putamen and internal capsule, and implications for minimizing functional and vascular injury during neurosurgical approaches and revascularization procedures.

• Anatomical Focus: The study investigates the microanatomy of white matter fiber tracts and vascular structures lateral to the internal capsule, using fiber dissection and vessel perfusion techniques on human cadaveric brains.

• Key Structures: Major fiber tracts identified include the arcuate fasciculus (AF), superior longitudinal fasciculus (SLF), frontal aslant tract (FAT), middle longitudinal fasciculus (MdLF), uncinate fasciculus (UF), and inferior fronto-occipital fasciculus (IFOF); the main vascular structures are branches of the middle cerebral artery (MCA) and lenticulostriate arteries (LSAs), each accompanied by lenticulostriate veins (LSVs).

• Vascular Territories: Superficial arteries supply only the gray matter of the lateral brain surface, while deeper white matter and basal ganglia receive blood from LSAs originating from the M1 segment of the MCA; there is no direct communication between insular arteries and LSAs, with the external capsule marking their vascular boundary.

• Surgical Implications: Kocher’s point, a standard neurosurgical entry site, traverses the posterior middle frontal gyrus, SLF III, external capsule, and basal ganglia, avoiding major arteries, veins, and critical fiber tracts such as the AF and internal capsule, thus minimizing functional risk.

• Clinical Relevance: Understanding the course of LSAs and LSVs is crucial for safe neurosurgical procedures in the basal ganglia and insular region, as injury to these vessels can cause severe neurological deficits; the study provides anatomical evidence supporting the safety of the Kocher’s point approach.

• Functional Anatomy: The AF is essential for language by connecting Broca’s and Wernicke’s areas; the internal capsule is critical for motor and sensory information transfer between cortex and brainstem/spinal cord.

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Impact of GLP-1 receptor agonists on idiopathic intracranial hypertension clinical and neurosurgical outcomes

J Neurosurg 143:1037–1047, 2025

This multicenter propensity-matched cohort study examines the association between glucagon-like peptide-1 receptor agonist (GLP-1-RA) therapy and clinical, neurosurgical, and mortality outcomes in adult patients with idiopathic intracranial hypertension (IIH) using the TriNetX electronic health record network. Outcomes at 6 months and 1 year include BMI change, new-onset headaches, visual and cognitive deficits, acetazolamide use, surgical interventions, and mortality.

Findings show greater weight loss and significantly lower odds of visual and cognitive deficits, acetazolamide use, shunt placement at one year, and markedly reduced all-cause mortality among GLP-1-RA users. The authors highlight biological plausibility, acknowledge limitations of retrospective administrative data, and call for randomized prospective trials to confirm causality and optimize treatment strategies.

• GLP-1 receptor agonists (GLP-1-RAs) are associated with significantly improved clinical outcomes in idiopathic intracranial hypertension (IIH), including reduced visual and cognitive deficits, headaches, acetazolamide use, need for shunt placement, and mortality compared to matched controls.

• Weight loss achieved with GLP-1-RAs is greater than with standard care: mean BMI reduction of 1.083 kg/m² at 6 months and 1.635 kg/m² at 1 year, versus 0.695 and 0.758 kg/m² in controls, respectively (p < 0.001).

• Odds of new-onset symptoms are significantly lower with GLP-1-RA treatment at 6 months for headache (OR 0.660), visual deficits (OR 0.423), cognitive deficits (OR 0.368), and acetazolamide use (OR 0.295); most effects persist at 1 year, including a significant reduction in shunt placement (OR 0.375).

• Mortality rates are substantially reduced in the GLP-1-RA group at both 6 months (OR 0.060) and 1 year (OR 0.115), with statistical significance confirmed by Kaplan-Meier survival analysis.

• Mechanisms of benefit may include both weight reduction and direct pharmacological effects, such as reduced cerebrospinal fluid secretion via GLP-1 receptors in the choroid plexus, and anti-inflammatory/neuroprotective actions in the brain.

• GLP-1-RA therapy allows for decreased reliance on acetazolamide, which is associated with more adverse effects, and offers a favorable safety profile—most commonly transient nausea.

• Study limitations include retrospective design, reliance on de-identified administrative data, inability to assess patient adherence, dosage, or causality, and residual confounding despite propensity score matching.

• Future directions call for larger, prospective randomized controlled trials to validate efficacy, clarify mechanisms (weight loss vs. direct CNS effects), and refine IIH treatment strategies.

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Decreasing delayed cerebral infarction after aneurysmal subarachnoid hemorrhage using active blood clearance and prevention of delayed cerebral ischemia: results of a 16-year patient registry

J Neurosurg 143:928–938, 2025

Active blood clearance and prevention of delayed cerebral ischemia (ABCD) after aneurysmal subarachnoid hemorrhage significantly reduced delayed cerebral infarction rates and improved outcomes in high-risk patients, using methods like intrathecal irrigation, urokinase, and nimodipine, according to a 16-year registry study.

Active blood clearance and prevention of delayed cerebral ischemia (ABCD) was introduced for patients with aneurysmal subarachnoid hemorrhage (aSAH) to reduce delayed cerebral infarction (DCI) using methods like intrathecal irrigation, fibrinolysis with urokinase, and intrathecal nimodipine.

• Four ABCD methods were developed: stereotactic catheter ventriculocisternostomy (STX-VCS), intraoperative cisternoventricular catheter (CVC), ventriculolumbar irrigation (VLI), and lumbo-lumbar irrigation (LLI).

• Implementation of ABCD in high-risk patients led to a significant reduction in DCI rates from 21.2% to 7.7% and a 70% decrease in per-patient DCI burden.

• Patients selected for ABCD had higher initial blood load and worse clinical status, but still showed improved outcomes, especially those with high Hijdra scores (≥30).

• Pressure-controlled VLI and intraoperative CVC emerged as the most practical and widely applicable ABCD techniques.

• Complication rates were low and ABCD was considered safe, with rare adverse events and no increase in infection rates.

• The study suggests ABCD outperforms previous DCI prevention strategies and recommends multicenter trials for further validation.

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Minimally invasive burr hole craniotomy versus drill hole craniotomy for the management of chronic subdural hematoma: a randomized clinical trial

Neurosurg Focus 59(4):E2, 2025

A randomized trial compared hollow screw (HS) trephination under local anesthesia to enlarged burr hole (BH) trepanation under general anesthesia for chronic subdural hematoma. HS showed similar recurrence and clinical outcomes, but with shorter operation time, hospital stay, and lower costs, supporting its use in older, comorbid patients.

• A randomized clinical trial compared hollow screw (HS) trephination under local anesthesia to enlarged burr hole (BH) craniotomy under general anesthesia for chronic subdural hematoma (cSDH) evacuation.

• 131 patients (mean age 77) were analyzed; both groups were similar in demographics and risk factors.

• HS had a higher, but not statistically significant, recurrence rate compared to BH (HS 47.8% vs BH 31.2%, p = 0.06).

• Clinical outcomes and complication rates were equivalent between HS and BH groups.

• HS procedures were significantly less invasive, with shorter operation times (median 21 vs 33.5 minutes) and shorter hospital stays (median 3.0 vs 4.3 days).

• HS treatment was less costly than BH (806 vs 1884.70 euros per case, excluding infrastructure).

• HS trephination is a reasonable alternative to BH, especially for elderly or multimorbid patients, given similar outcomes and improved efficiency.

• Study limitations include single-center design, limited sample size, and lack of blinding.

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Risk Factors Associated With Revision Microdiscectomy or Subsequent Spinal Fusion Within Two Years of Index Lumbar Microdiscectomy

Spine 2025;50:1392–1399

This large retrospective study found that within two years of lumbar microdiscectomy, 5.5% required revision surgery and 6.6% required spinal fusion. Age 40–59, female sex, and at least one Charlson Comorbidity Index (CCI) comorbidity significantly increased the risk of subsequent fusion, but not revision microdiscectomy.

Revision microdiscectomy rates after index lumbar microdiscectomy were 3.5% at one year and 5.5% at two years.

• Lumbar fusion rates were 2.9% at one year and 6.6% at two years after index surgery.

• Age 40–59, female sex, and presence of at least one Charlson Comorbidity Index (CCI) comorbidity significantly increased risk of lumbar fusion, but not revision microdiscectomy.

• Having ≥1 CCI comorbidity increased the likelihood of needing fusion by about 80%.

• Specific comorbidities (e.g., congestive heart failure, peripheral/cerebrovascular disease, diabetes) were strong predictors for time-to-fusion.

• Age, sex, and CCI score were not predictive of time-to-revision microdiscectomy.

• Results suggest CCI may help identify patients at higher risk for spinal fusion after microdiscectomy.

• Findings may guide surgeons in perioperative decision-making and patient counseling.

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Development and Validation of Interpretable Machine Learning Models Incorporating Paraspinal Muscle Quality to Predict Cage Subsidence Risk Following Posterior Lumbar Interbody Fusion

Spine 2025;50:1375–1385

This multicenter retrospective study developed and validated an interpretable LightGBM machine learning model incorporating paraspinal muscle quality and bone metrics to accurately predict cage subsidence risk after PLIF. Key risk factors included lower psoas muscle index, higher fat infiltration, reduced bone density, and suboptimal cage parameters.

• A machine learning model (LightGBM) was developed to predict cage subsidence risk after PLIF, achieving high accuracy (AUC 0.9752, 92% accuracy, F1 score 0.92).

• Key independent risk factors include lower psoas muscle index (PMI), higher fat infiltration (FI), reduced bone density (HU value, VBQ), suboptimal cage position/height, and greater postoperative changes in intervertebral height (IH) and segmental angle (SA).

• Paraspinal muscle quality was a major contributor; removing muscle indicators reduced model accuracy substantially.

• Patients with cage subsidence had poorer paraspinal muscle and bone quality compared to those without subsidence.

• The model was externally validated and deployed as a web-based tool for real-time, individualized clinical risk assessment.

• Findings support personalized surgical planning and risk mitigation strategies for PLIF patients.

• The study emphasizes a multifactorial approach, integrating skeletal, muscular, and surgical parameters for optimal prediction.

• Limitations include retrospective design, use of a single cage type, and lack of comorbidity indices; further prospective studies are needed.

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Risk Factors for Postoperative Cerebrospinal Fluid Fistulas After Craniotomy and Craniectomy: A Systematic Review and Meta-Analysis

Acta Neurochirurgica (2025) 167:264

This systematic review and meta-analysis identified higher postoperative CSF fistula risk after infratentorial and tumor surgeries, and with primary closure. Patch grafts and watertight techniques reduce leak rates. CSF leaks are strongly linked to postoperative infections, highlighting the importance of preventive strategies in cranial neurosurgery.

Postoperative cerebrospinal fluid (CSF) fistulas are a common complication after craniotomy and craniectomy, with incidence rates ranging from 1% to 10%.

• Infratentorial surgeries have a higher CSF leak rate (7.9%) than supratentorial ones (4.6%).

• Tumor surgeries show greater risk of CSF leak than vascular procedures (odds ratio 1.82).

• Primary dural closure has a higher leak rate (12.3%) compared to patch grafts (8.5%).

• Watertight dural closure trends toward fewer leaks, but current evidence is not statistically significant.

• CSF leaks are strongly associated with postoperative infections (34.1%).

• Prevention of CSF leaks is crucial to reduce infection risk and improve surgical outcomes.

• Limitations include heterogeneous study definitions, inconsistent reporting of comorbidities, and lack of standardized data on closure techniques.

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Long-term outcomes of peripheral nerve field stimulation in patients with refractory trigeminal neuralgia: a cohort study

J Neurosurg 143:982–986, 2025

Peripheral nerve field stimulation (PNFS) for refractory trigeminal neuralgia showed high long-term treatment failure, especially in females, with frequent complications and revisions. Only half of male patients reported lasting benefit. PNFS should be considered cautiously for this condition.

Peripheral nerve field stimulation (PNFS) was studied for refractory trigeminal neuralgia with a long-term follow-up.

Fifteen patients (6 male, 9 female; median age 70) were included, with a median follow-up of 93 months.

PNFS had a high rate of long-term treatment failure, especially in females.

The median time to treatment failure was 2 years (5.1 years in males, 1.5 years in females; p = 0.003).

Only 3 patients (all male) reported ongoing benefit.

Complications and revision surgeries were common (4 patients, 7 revisions).

No significant differences in outcomes were found between classic and secondary trigeminal neuralgia or by patient age.

PNFS should be considered cautiously due to limited long-term efficacy and frequent complications.

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Resectability of White Matter Tracts in Patients With Language-Critical Gliomas

Neurosurgery 00:1–9, 2025 (Published Online, October 15, 2025)

Resection of white matter tracts (WMTs) in language-critical glioma surgery robustly predicts permanent postoperative language deficits, particularly when parietal and temporal segments are involved. Frontal lobe WMTs are often safely resectable. Anatomical stratification enhances prediction, supporting data-driven, segment-specific surgical planning.

Resecting language-associated white matter tracts (WMTs) in glioma surgery robustly predicts permanent postoperative language deficits (PLDs).

• Frontal lobe WMT segments (e.g., arcuate fasciculus, IFOF, UF, SLF, FAT) are often resectable without causing PLDs.

• Resections in the temporoparietal junction (TPJ) and middle temporal lobe (MTL) significantly increase the risk of PLDs.

• Anatomically stratifying resections to parietal and temporal tracts improves prediction accuracy for PLDs (PPV increases to 50%).

• Volume of tract resected does not correlate with risk of PLDs; specific tract location is more important.

• Broca area and underlying white matter can often be resected safely, challenging traditional localizationist models.

• Combining imaging data with intraoperative mapping remains essential due to some nonfunctional tract segments leading to low PPV.

• Study limitations include small sample size, operator variability in tractography, and need for multicenter validation.

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