Author: cba

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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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Customized Titanium Implants for Cranial Fibrous Dysplasia: A Personalized Surgical Approach and Single-Center Experience

Operative Neurosurgery 30:100–108, 2026

This single-center clinical series reports on 33 patients with monostotic cranial fibrous dysplasia treated with computer-assisted resection and reconstruction using patient-specific, 3D‑printed titanium cranioplasty implants. Methods detail high-resolution CT planning, surgeon‑engineer collaboration for CAD/CAM templates, intraoperative guidance, standardized perioperative care, and long-term radiological and FACE-Q patient‑reported outcome follow-up.

Results show complete tumor resections, favorable cosmetic outcomes, no postoperative complications or recurrences across extended follow-up, and high patient satisfaction; discussion addresses material selection, cost (≈$3000 per implant), production time, accessibility in low-resource settings, and the need for comparative studies.

Patient-Specific Titanium Implants: Customized, computer-aided design (CAD) and manufacturing (CAM) titanium implants enable precise resection and effective reconstruction for cranial fibrous dysplasia (CFD), resulting in excellent cosmetic outcomes and no postoperative complications or recurrences in a 33-patient series.

Surgical Process: Preoperative high-resolution CT scans and 3D modeling are used for surgical planning, including mirrored contralateral anatomy for symmetry; intraoperative templates guide tumor resection, and implants are secured with miniscrews.

Clinical Outcomes: All patients achieved complete tumor removal, satisfactory cosmetic results confirmed by postoperative CT, and no surgical site infections or cerebrospinal fluid leaks during a mean follow-up of 76–108 months.

Patient Satisfaction: High patient-reported satisfaction was observed, with FACE-Q scores indicating 84.8% of patients highly satisfied (score ≥85) and no patients dissatisfied with surgical outcomes.

Material Advantages: Titanium implants are favored for their biocompatibility, mechanical strength, and low infection rates compared to other materials like PEEK and PMMA, making them especially suitable for CFD reconstruction.

Cost and Accessibility: Average total cost per implant was $3000, with a 4-week production time; while feasible in middle-income settings, access remains limited in low-resource environments due to financial and infrastructural barriers.

Limitations: The study’s retrospective, single-center design, absence of a comparative cohort, and variable follow-up duration limit generalizability and long-term conclusions.

Future Directions: Broader adoption of CAD/CAM and patient-specific implants in craniofacial surgery may improve outcomes, but further comparative and cost-effectiveness studies are needed, especially in resource-constrained settings.

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Spinal versus general anesthesia in robotic minimally invasive transforaminal lumbar interbody fusion: a comparative study on surgical outcomes

J Neurosurg Spine 44:99–107, 2026

This clinical study compares spinal anesthesia (SA) versus general anesthesia (GA) for robot-assisted minimally invasive transforaminal lumbar interbody fusion (RA‑MIS TLIF), reporting retrospective outcomes from 209 patients treated 2018–2024. Primary findings show SA patients had significantly shorter operative times, lower immediate postoperative pain scores, reduced estimated blood loss, and shorter hospital length of stay after propensity score matching and regression adjustment.

The authors contextualize results within advances in robotic spinal surgery and awake spine techniques, discuss safety and potential cost and opioid‑reduction benefits, and acknowledge limitations including retrospective design, single‑center data, and reduced matched cohort size. Conclusions support SA as a safe, efficient approach for RA‑MIS TLIF with calls for larger prospective studies and formal patient‑selection guidelines.

Spinal Anesthesia (SA) vs General Anesthesia (GA): In robot-assisted minimally invasive transforaminal lumbar interbody fusion (RA-MIS TLIF), SA significantly reduces operative times, postoperative pain, and hospital length of stay compared to GA, with no increase in complications or adverse outcomes.

Robotic Assistance Benefits: Robotic technology in spine surgery improves pedicle screw placement accuracy, reduces radiation exposure, and is associated with lower complication and revision rates, enhancing surgical safety and efficiency.

Study Design: A retrospective analysis of 209 patients (31 SA, 178 GA) from 2018–2024, with propensity score matching applied to control for confounders, allowing fair comparison between SA and GA cohorts for single-level procedures.

Key Outcomes (After Matching): SA cohort had shorter median total OR time (159 vs 283 min), procedure time (115 vs 201 min), lower intraoperative blood loss (25 vs 50 mL), lower first postoperative pain scores (median VAS 0 vs 5), and reduced mean length of stay (0.90 vs 2.64 days) compared to GA.

Patient Selection: The choice between SA and GA was based on patient preference and eligibility, with all SA cases being single-level procedures and comparable baseline demographics after matching.

Safety Profile: No increase in intraoperative or postoperative complications was observed with SA; screw placement accuracy remained high with robotic assistance.

Implications for Practice: Combining SA with RA-MIS TLIF offers a safe, efficient, and patient-centered approach that may lower healthcare costs and opioid requirements by reducing pain and hospitalization.

Limitations: Single-center, retrospective design with a relatively small matched cohort may limit generalizability; further prospective, multicenter studies are needed to validate these findings.

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Erector spinae plane block during standalone anterior lumbar surgery: impact on early ambulation, length of stay, and inpatient opioid use

J Neurosurg Spine 44:90–98, 2026

This clinical retrospective study assesses the impact of erector spinae plane block (ESPB) as an adjunct to multimodal analgesia in standalone anterior lumbar procedures (ALIF and lumbar TDR). Outcomes compared between ESPB and non-ESPB cohorts include in-hospital pain scores, opioid consumption (MME), time to ambulation, length of stay (LOS), and opioid-related complications.

Results show ESPB associated with lower day-of-surgery pain scores, earlier ambulation, and shorter LOS, with reduced in-hospital oral MME in univariate analysis; preoperative opioid use predicted higher perioperative opioid consumption and urinary retention despite ESPB. The authors emphasize ESPB as a component of enhanced recovery protocols and note limitations of retrospective design and sample size.

Erector Spinae Plane Block (ESPB): ESPB is a regional analgesic technique used as an adjunct in anterior-only lumbar surgeries, such as ALIF and total disc replacement, aiming to improve perioperative pain control and recovery outcomes.

Reduced Pain and Opioid Use: ESPB significantly lowers pain scores on the day of surgery and reduces in-hospital opioid use, especially oral morphine milligram equivalents (MMEs), compared to patients not receiving ESPB.

Shorter Hospital Stay: Patients receiving ESPB experience a significantly shorter hospital length of stay (LOS) and are more likely to be discharged earlier, including same-day discharge, than those without ESPB.

Faster Ambulation: ESPB is associated with a significantly shorter time to first ambulation after surgery, facilitating earlier rehabilitation.

Predictors of Opioid Use: Baseline (preoperative) opioid use is the strongest predictor of higher perioperative opioid requirements and is also linked to a higher incidence of postoperative urinary retention, regardless of ESPB administration.

Subgroup Benefits: Among ESPB patients, those with a shorter LOS (<2 days) had earlier ambulation, lower opioid use, and lower pain scores on postoperative day 1, indicating enhanced early recovery.

Multimodal Pain Management: ESPB should be considered as one component within a comprehensive multimodal pain management strategy (such as ERAS protocols), rather than as a standalone intervention.

Study Limitations: The findings are limited by the retrospective design, potential selection bias, lack of randomization, and incomplete data on preoperative opioid use, highlighting the need for larger, prospective studies

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Predicting Intracranial Pressure Levels: A Deep Learning Approach Using Computed Tomography Brain Scans

Neurosurgery 98:256–268, 2026

This clinical study evaluates deep learning models that predict whether intracranial pressure (ICP) exceeds 15 mm Hg from brain CT scans, integrating demographic and Glasgow Coma Scale data into image inputs. Four 3D architectures—including MobileNetV2 3D and DenseNet201 3D—were trained on 578 paired CT–ICP cases with preprocessing, augmentation, and explainability via class activation maps.

Results show MobileNetV2 3D achieved the best generalization (AUC 0.883, recall 81.8%), with demographic embedding improving performance; limitations include single-center data, class imbalance, and lack of external validation, and authors recommend multicenter expansion and refined region-specific feature extraction before clinical deployment.

Intracranial Pressure (ICP) Risk: Elevated ICP is a critical, potentially fatal condition requiring rapid diagnosis and intervention, but current gold-standard invasive monitoring methods carry risks and are not always feasible in emergency settings.

Noninvasive ICP Assessment Challenge: Existing noninvasive methods (e.g., CT-based qualitative markers) lack sufficient accuracy and reliability for routine emergency use, highlighting the need for improved approaches.

Deep Learning Solution: Four deep learning models were trained on a custom dataset of 578 paired brain CT scans, demographic information, and Glasgow Coma Scale (GCS) scores to classify whether ICP exceeds 15 mm Hg, addressing the gap in noninvasive, rapid ICP estimation.

Data Integration Innovation: Demographic and GCS data were embedded and merged with CT imaging, creating a multimodal input that improved model performance compared to imaging-only approaches.

Best Model Performance: The MobileNetV2 3D model with demographic data achieved the highest test AUC of 88.3% and recall of 81.8%, outperforming other architectures and showing promise for high-sensitivity emergency applications.

Explainability: Class Activation Maps (CAMs) were used to visualize which regions of the brain CT scans influenced model predictions, enhancing transparency and interpretability of the AI system.

Limitations: The study’s main limitations include a relatively small, single-center dataset with class imbalance, lack of external/multicenter validation, and potential inconsistencies due to timing mismatches between CT and ICP measurements.

Clinical Impact & Future Directions: This AI approach could reduce reliance on invasive monitoring and accelerate ICP triage in neurocritical care; further multicenter studies, prospective validation, and expansion to multiclass classification are needed for clinical deployment.

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Determinants of survival after re-resection for recurrent glioblastoma: a meta-analysis

Acta Neurochirurgica (2026) 168:11

This systematic review and meta-analysis examines prognostic factors affecting survival after re-resection for recurrent glioblastoma, synthesizing data from 30 studies (1,741 pooled patients). Key findings identify gross total resection and MGMT promoter methylation as strong positive predictors, while age and low preoperative KPS associate with poorer outcomes; adjuvant therapies and time to re-resection showed inconsistent effects.

The paper details search methods, risk-of-bias assessment, statistical approaches, sensitivity analyses for IDH status, and study heterogeneity limitations. Conclusions emphasize patient selection for re-resection based on functional status and molecular markers and call for prospective, standardized trials and individual-patient data analyses to refine management of recurrent glioblastoma.

Gross Total Resection (GTR): Achieving GTR at re-resection for recurrent glioblastoma is significantly associated with improved survival compared to subtotal resection (pooled HR ~0.52–0.70, p < 0.001).

MGMT Promoter Methylation: Patients with methylated MGMT promoter status at recurrence have significantly better survival following re-resection (multivariate HR = 0.45, 95% CI: 0.27–0.76, p < 0.01).

Preoperative Karnofsky Performance Status (KPS): A KPS score <70 before re-resection is strongly associated with poorer survival outcomes (HR = 2.25, 95% CI: 1.59–3.19, p < 0.001).

Age: Older age is modestly associated with worse survival after re-resection, but the effect size is small (HR = 1.02, 95% CI: 1.01–1.03, p < 0.001); age alone should not preclude aggressive treatment.

Adjuvant Chemotherapy and Radiotherapy: No significant survival benefit was found for adjuvant chemotherapy (HR = 0.69, p = 0.33), radiotherapy (HR = 0.62, p = 0.50), or combined chemoradiotherapy after re-resection.

Time to Re-resection: Longer time intervals between initial surgery and re-resection did not show a statistically significant association with improved survival (HR = 0.69, p = 0.16).

Personalized Approach: Selection for re-resection should prioritize patients with good performance status, favorable tumor characteristics, and methylated MGMT promoter, with GTR as a key goal.

Evidence Limitations: Most included studies were retrospective with heterogeneity in definitions and reporting; high-quality prospective trials are needed to refine prognostic assessments and treatment strategies.

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Electrophysiological monitoring of trigeminal nerve sensory root using sensory-masseter response for microvascular decompression in trigeminal neuralgia

Acta Neurochirurgica (2026) 168:13

This study presents a novel intraoperative electrophysiological technique—the sensory-masseter response (SMR)—for localizing neurovascular compression (NVC) during microvascular decompression (MVD) for trigeminal neuralgia. In 34 patients, SMR was recorded in 82.4% and showed strong spatial correlation with intraoperatively identified NVC, with significantly lower stimulation thresholds at compression sites (median 0.3 mA).

The authors describe methodology, threshold analyses, mechanistic hypotheses linking focal demyelination and sensory-motor anastomoses to SMR, illustrative cases, safety considerations, and limitations. They conclude SMR offers high spatial specificity as a potential real-time adjunct for MVD, but recommend larger studies to validate clinical utility.

Sensory-Masseter Response (SMR) Technique: SMR is a novel intraoperative electrophysiological monitoring method that applies microcurrent stimulation to the intracranial trigeminal sensory root and records compound muscle action potentials (CMAPs) from the masseter muscle to localize neurovascular compression (NVC) during microvascular decompression (MVD) for trigeminal neuralgia (TN).

High Spatial Specificity and Correlation with NVC: SMR was successfully recorded in 82.4% of cases (28/34), with a strong spatial correlation between SMR-positive sites and intraoperatively identified NVC (p < 0.001).

Lower Stimulation Threshold at NVC Sites: The stimulation threshold required to elicit SMR was significantly lower at NVC sites (median 0.3 mA, IQR 0.2–0.4 mA) compared to distal, central, or non-compressed segments, indicating localized neural hyperexcitability likely due to demyelination.

Mechanistic Basis—Sensory-Motor Root Anastomoses: SMR is likely mediated by abnormal anastomotic pathways between the trigeminal sensory and motor roots at the NVC site, enabling direct excitation of the masseter muscle and bypassing the central reflex arc.

Clinical Utility and Limitations: SMR provides real-time functional feedback for intraoperative localization of NVC, but its clinical value and influence on surgical outcomes require further validation in larger, controlled studies.

Potential Pathogenic Insight: The ability to elicit SMR at NVC sites supports the hypothesis that focal demyelination and abnormal sensory-motor conduction contribute to TN pathogenesis and characteristic symptoms like chewing-triggered pain.

Safety Considerations: SMR stimulation can cause transient blood pressure elevation due to sympathetic activation; precautions include deepening anesthesia and monitoring hemodynamics during stimulation.

Study Limitations: The main limitations include small sample size, absence of SMR testing in non-TN or healthy controls, possible technical constraints in nerve exposure, and restriction of recordings to the masseter muscle only.

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Does segmental alignment matter? A novel understanding of segmental compensation and reciprocal change following single-level lumbar reconstruction

J Neurosurg Spine 44:72–79, 2026

This clinical study analyzes segmental compensation and reciprocal changes after single-level L5–S1 anterior lumbar interbody fusion in 100 adults with normal preoperative lumbar lordosis. Using intradiscal angle, motion segment angle, and disc heights, the authors show significant index-level lordosis restoration and correlated increases in overall lumbar lordosis at 1 month and 1 year.

The paper documents consistent reciprocal decreases in lordosis at adjacent L4–5 and L3–4 levels, provides predictive linear equations for adjacent-level change based on index-level IDA change, and argues that restoring segmental lordosis may prevent maladaptive compensation and reduce adjacent segment disease risk, while noting limitations and need for longer follow-up.

Segmental Compensation: Adjacent lumbar spine segments compensate for loss of lordosis at a pathologic segment by increasing their own segmental lordosis to maintain overall lumbar lordosis (LL) within the normal range.

Reciprocal Change After Fusion: Restoration of lordosis at the L5–S1 level via anterior lumbar interbody fusion (ALIF) leads to a significant, measurable decrease in segmental lordosis at adjacent levels (L4–5 and L3–4), demonstrating a reciprocal relationship.

Predictive Model: The degree of reciprocal loss of lordosis at adjacent levels can be predicted using linear equations based on the lordosis gain at the fused segment (e.g., 1-year adjacent level decrease in IDA = −0.195 × [index level 1-year IDA change] + 0.332).

Global Alignment Maintenance: Despite significant increases in lordosis at the surgical level, total lumbar lordosis does not increase by the same amount due to compensatory decreases at adjacent levels, maintaining global alignment.

Clinical Implication: Proper restoration of segmental lordosis at the surgical level may help prevent negative consequences of persistent compensation at adjacent segments, potentially reducing the risk of adjacent segment disease.

Study Population: Findings are based on 100 adults with normal preoperative LL (PI–LL < 10°) who underwent single-level L5–S1 ALIF and achieved ≥5° increase in segmental lordosis postoperatively.

Correlation With Outcomes: Changes in lordosis at the surgical segment positively correlate with changes in overall lumbar lordosis at both 1 month and 1 year postoperatively.

Long-Term Impact: The persistence of reciprocal changes at adjacent segments up to 1 year suggests that segmental compensatory mechanisms are durable and may influence long-term spinal health and surgical planning.

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Minimally invasive lumbar decompression versus open decompression for lumbar spinal stenosis: a propensity score–matched analysis

J Neurosurg Spine 44:55–61, 2026

This propensity score–matched retrospective study compares minimally invasive lumbar decompression (mild) with open decompression for lumbar spinal stenosis at a tertiary multisite center from 2005–2024. Primary outcomes included pain change (NRS), reoperation, and perioperative complications, with MCID defined as 30% NRS improvement.

Results show open decompression yielded greater pain improvement, higher MCID attainment, and lower overall reoperation rates, while mild had fewer durotomies but more neurological deficits. The authors recommend independent prospective studies to validate comparative efficacy and cost-effectiveness and note limitations including retrospective design and incomplete radiographic severity data.

Open decompression is more effective than the mild (minimally invasive lumbar decompression) procedure for achieving clinically significant pain improvement in patients with symptomatic lumbar spinal stenosis (43.1% vs 22.2% reached MCID; p < 0.001).

Reoperation rates are higher after the mild procedure compared to open decompression (46.2% vs 29.3%; p = 0.008), indicating less durable symptom relief with mild.

Pain outcomes favor open decompression, with patients reporting lower pain scores at last follow-up (mean NRS 2.3 vs 5.4; p < 0.001) and greater overall improvement from baseline.

Complication profiles are similar overall, but mild is associated with higher rates of postoperative neurological deficits (6.3% vs 0.6%; p = 0.003), while open decompression has a higher rate of durotomy (2.9% vs 0%; p = 0.024).

Procedure characteristics: The mild procedure is performed percutaneously through a small incision, typically by pain medicine physicians, and targets debulking the ligamentum flavum without muscle dissection.

Study limitations include retrospective design, incomplete matching for stenosis severity and baseline pain, and missing data on some outcomes, suggesting a need for prospective studies.

Existing literature on mild is often industry-sponsored and lacks direct comparison to open decompression; independent studies show mild may be less effective and more likely to require further surgery.

Clinical recommendation: Open decompression remains the gold standard for patients with symptomatic lumbar spinal stenosis who fail conservative management, while the mild procedure may offer less pain relief and higher reoperation risk.

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Comparative Effectiveness of Conservative Management Versus Surgical Fixation in Acute Type II Odontoid Fractures

Neurosurgery 98:61–72, 2026

This retrospective single-center study compares radiological and functional outcomes of conservative versus surgical management for acute type II odontoid fractures in an elderly cohort treated from 2015–2023. Results show surgical fixation markedly increases radiographic union rates, while conservative bracing predominated and delivered superior early pain control with similar long-term functional independence.

Multivariable modeling identified surgery as the strongest positive predictor of union, whereas age ≥80, smoking, osteoporosis, higher frailty, and angulation ≥11° reduced union odds and lowered likelihood of surgical selection. Complication rates and hospital stays were higher after surgery, supporting individualized treatment decisions balancing union probability, pain, frailty, and perioperative risk.

Surgical fixation increases the odds of fracture union in acute type II odontoid fractures (adjusted OR = 6.6), but does not improve long-term functional independence or survival compared to conservative management.

Conservative management (mainly rigid collars) is preferred for elderly or frail patients and achieves similar functional outcomes (modified Rankin Scale ≤2: 75% vs 73%) and better early pain control (75% vs 47%) than surgery, despite lower union rates.

Fracture union rates are significantly higher after surgery (44% vs 10% with conservative treatment, P < .01), but most conservatively managed patients achieve stable nonunion without adverse functional impact.

Advanced age (≥80 years), frailty, smoking, osteoporosis, and fracture angulation ≥11° are all strong negative predictors of fracture union, regardless of treatment approach.

Surgical patients are typically younger, less frail, and have greater fracture displacement or posterior displacement, reflecting selection bias in surgical decision-making.

Complication rates are higher with surgery (40% vs 2% for conservative), and surgical patients have longer hospital stays (median 11 vs 3 days), but most complications do not require reoperation.

Mortality rates at five years are similar between conservative and surgical groups (52% vs 53%), indicating no survival advantage with operative intervention.

Conservative treatment is a safe, effective option for most elderly or frail patients with type II odontoid fractures, reserving surgery for younger, medically fit individuals or those with unstable fracture patterns

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Long-Term Outcomes of Surgical Clipping of Woven EndoBridge-Eligible Middle Cerebral Artery Bifurcation Aneurysms

Operative Neurosurgery 30:18–25, 2026

This clinical study evaluates long-term outcomes of microsurgical clipping for middle cerebral artery (MCA) wide-neck bifurcation aneurysms that meet radiographic criteria for treatment with the Woven EndoBridge (WEB) device. Using a retrospective review of a prospectively maintained registry, the authors compare functional outcomes, complication rates, recurrence, and retreatment against published WEB and clipping cohorts.

Results show high surgical efficacy: 99% treatment success, 94.1% of unruptured cases achieving final mRS ≤2, a 4.9% morbidity rate, and 0% mortality, with lower retreatment and higher complete occlusion rates than reported WEB series. The authors conclude microsurgical clipping remains a reliable option for MCA WNBAs and recommend location-specific subgroup analyses in future WEB studies.

Microsurgical Clipping Outcomes: Surgical clipping of WEB-eligible middle cerebral artery (MCA) wide-necked bifurcation aneurysms (WNBAs) achieved a 99% treatment success rate, 4.9% morbidity, 0% mortality, and 94.1% good functional outcomes (mRS ≤2) in unruptured cases, with low recurrence and retreatment rates.

Comparison to WEB Device: Clipping resulted in higher complete occlusion rates, lower retreatment rates, and lower thromboembolic complication rates compared to endovascular treatment with the Woven EndoBridge (WEB) device for MCA WNBAs.

Functional Outcomes: Both ruptured and unruptured aneurysms treated surgically showed excellent or improved functional status at follow-up, with 91.8% of unruptured and 94.1% of ruptured cases experiencing stable or improved mRS scores.

Complication Profile: Thromboembolic complications occurred in 5.9% of unruptured cases, with permanent neurological deficits in 4.9% and no surgical mortality; intraoperative rupture was rare (2.0%).

Limitations of WEB Evidence: Most WEB studies pooled multiple aneurysm locations, making it difficult to assess location-specific efficacy; at the MCA, WEB showed higher retreatment and thromboembolic rates than clipping, and lower rates of complete occlusion.

Treatment Selection: MCA aneurysms are often suitable for surgical clipping due to their accessible location and favorable anatomy, especially at experienced centers, supporting a “clip-first” approach for many MCA WNBAs.

Study Limitations: Findings are based on a retrospective, single-center cohort at a high-volume academic institution, limiting generalizability and direct comparison to randomized or multicenter WEB trials.

Clinical Recommendation: Both clipping and WEB are effective for MCA WNBAs, but surgical clipping may offer superior durability and occlusion; treatment choice should be individualized through shared decision-making, not solely based on minimally invasive appeal.

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Artificial intelligence–based deep learning model for evaluating procedural consistency in microvascular anastomosis

J Neurosurg 144:1–10, 2026

This study presents an LSTM-based deep learning model that objectively evaluates microvascular anastomosis performance by predicting hand-motion trajectories from MediaPipe-derived hand landmarks. It quantifies consistency using Kullback-Leibler divergence and validates complementary metrics—economy and flow of motion—comparing two expert neurosurgeons (repeat sessions) and one trainee in simulated end-to-side anastomoses.

Results show low KL divergence for experts versus higher divergence for the trainee, reflecting greater consistency and efficiency. The authors discuss methodology, model architecture choices, limitations in generalizability, and potential integration into microsurgical training workflows for objective skill assessment.

Deep Learning Model: An LSTM-based neural network was developed to objectively assess consistency and precision in microvascular anastomosis by predicting and comparing suturing hand movements using video-based hand landmark tracking, eliminating the need for physical sensors.

Hand Tracking Technology: The model utilized MediaPipe Hand Landmarker, a CNN-based system that detects 21 hand landmarks from standard video, enabling detailed, sensor-free motion analysis during microsurgical simulation.

Performance Metrics: Three primary metrics were used: Kullback-Leibler (KL) divergence for consistency, economy of motion (mean Euclidean distance of hand movement), and flow of motion (median time per suture), providing quantitative, objective evaluation of surgical skill.

Experimental Setup: Two expert neurosurgeons performed microanastomosis simulations (interrupted and continuous suturing) in two sessions one year apart, and a trainee performed the same task for comparison; all sessions were recorded and analyzed using the AI pipeline.

Results and Interpretation: Experts showed low KL divergence (high consistency) and efficient, rhythmic motion, while the trainee had higher KL divergence, longer suture intervals, and more variable motion, reflecting less developed skill.

Model Application: The approach enables rapid, automated assessment of multiple trainees using standard video equipment, supporting objective tracking of skill progression and facilitating feedback in training environments.

Model Rationale: LSTM architecture was chosen for its ability to model long-term temporal dependencies in sequential hand movement data, making it suitable for predicting surgical motion patterns over extended timeframes.

Limitations and Future Directions: Current findings are based on a small sample of experts and one trainee in a simulated environment; broader validation, metric standardization (especially for KL divergence), and extension to real operative settings are needed for generalizability.

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Spatial patterns of fat within the deep multifidus as a biomarker for chronic low back pain

The Spine Journal 26 (2026) 106−118

This clinical study maps spatial fat infiltration (FI) within the lumbar multifidus (MF) of 230 chronic low back pain (cLBP) patients using 3T IDEAL MRI and statistical parametric mapping to identify level- and region-specific FI patterns. The authors introduce a novel “fat-map” method and define a deep15 FI% (deepest 15% of MF) to compare regional FI with overall whole‑muscle FI across L1L2–L5S1.

Key results show elevated FI in the deep MF at L4L5 and L5S1 is associated with higher pain (PEG scores) and adjacent disc degeneration independent of age, sex, and BMI, while overall FI% is more strongly linked to demographic factors. The deep15 FI% emerges as a potential biomarker for cLBP, suggesting regional MF degeneration may better explain pain mechanisms than whole‑muscle summary measures.

Deep multifidus fat infiltration (FI): Elevated fat content in the deepest regions (deepest 15%) of the multifidus muscle at the lower lumbar spine (L4L5, L5S1) is more strongly associated with chronic low back pain (cLBP) symptoms and adjacent disc degeneration than overall muscle FI%.

Regional specificity: FI in the deep multifidus at lower lumbar levels is less influenced by age, sex, and BMI compared to overall FI%, making it a more specific biomarker for cLBP.

Novel biomarker (deep15 FI%): The “deep15 FI%” (mean fat fraction in the deepest 15% of the multifidus at L4L5/L5S1) is a regionally specific muscle quality measure, showing a stronger association with pain and disc degeneration than traditional whole-muscle FI% measures.

Demographic factors: Older age and female sex are associated with increased FI throughout the multifidus, while higher BMI mainly affects FI in the superficial 60% of the muscle, not the deep region at lower lumbar levels.

Pain association: Higher deep15 FI% at the lower lumbar levels is significantly associated with higher pain and pain interference scores (PEG survey), while overall FI% is not.

Disc degeneration link: Adjacent disc degeneration is the only degenerative spine feature consistently associated with increased deep multifidus FI at lower lumbar levels; other features (e.g., Modic changes, facet osteoarthritis) do not show this association when controlling for age, sex, and BMI.

Clinical implications: Deep multifidus FI could serve as a more precise imaging biomarker for cLBP and may guide future targeted interventions, though further longitudinal and interventional studies are needed to confirm causality and reversibility.

Limitations: The study’s spatial FI analysis is limited to radial (deep-to-superficial) direction and cross-sectional design; further research is needed to clarify causal mechanisms and intervention effects.

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Segmental Lordosis After Open Transforaminal Lumbar Interbody Fusion Using Expandable Oblique Versus Static Anterior Banana Cages

Operative Neurosurgery 30:78–89, 2026

This clinical research article compares segmental and lumbar lordosis outcomes after open transforaminal lumbar interbody fusion (TLIF) with posterior column osteotomy using either static anterior “banana” cages or obliquely placed expandable cages. In a single-surgeon retrospective cohort of 210 patients (327 segments), expandable cages produced a significantly greater median change in segmental lordosis (ΔSL) by 2.0° at six months, persisting after multivariate adjustment and propensity matching.

The study also reports inconsistent effects of cage type on overall lumbar lordosis (ΔLL), with subgroup and matched analyses yielding differing results, and found no difference in subsidence or complication rates. Findings emphasize the influence of preoperative segmental lordosis, segment level (notably L5–S1), and construct length on achieved correction, while noting limitations including retrospective design and lack of clinical outcomes.

Expandable Cages: Expandable obliquely placed cages in open transforaminal lumbar interbody fusion (TLIF) with posterior column osteotomy (PCO) produce a significantly greater median increase in segmental lordosis (ΔSL) of 2.0° compared to static anteriorly placed banana cages, representing a 50% increase.

Statistical Robustness: The greater segmental lordosis achieved with expandable cages remained significant after multivariate regression analysis and propensity score matching, confirming the reliability of the finding.

Overall Lumbar Lordosis (ΔLL): No clear advantage was found between cage types regarding the change in overall lumbar lordosis, with results varying depending on the statistical method used.

Surgical Technique Consistency: All surgeries were performed open with a full PCO using a consistent technique, minimizing confounding variables related to surgical approach or technique.

Preoperative Segmental Lordosis Impact: Segments with lower preoperative segmental lordosis (<15°) experienced the greatest increase in lordosis postoperatively, regardless of cage type.

L5-S1 Segment Benefit: Expandable cages were especially favorable at the L5-S1 segment, likely due to anatomical constraints that make insertion of large static cages more challenging at this level.

Complication and Subsidence Rates: No significant differences were observed between cage types in rates of complications, cage subsidence, or spondylolisthesis correction.

Clinical Outcomes Unclear: The study did not assess clinical outcomes, so the impact of the observed radiographic differences on patient-reported outcomes remains unknown.

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