Author: cba

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Fully automated image updating for brain shift compensation after dural opening

J Neurosurg 144:206–216, 2026

This study presents a fully automated intraoperative image-updating system that compensates for brain shift after dural opening by assimilating intraoperative stereovision (iSV) data into a biomechanical finite element model to deform preoperative MR (pMR) images into updated MR (uMR) images. The pipeline integrates FastSAM segmentation, vessel/sulcus feature registration, and FEM-based whole-brain deformation to produce clinically usable uMRs.

In fifteen open cranial cases, automated updates reduced mean target registration error from 6.2 mm (pMR) to 1.9 mm (uMR) and completed without user intervention in 3.9 ± 0.6 minutes. Results demonstrate robust segmentation (DSC 0.93), submillimeter iSV reconstruction accuracy, and potential for broader adoption, while noting limitations in small or featureless openings and need for deeper-structure validation.

Fully automated image updating: Developed and validated a fully automated system to update preoperative MRI images for brain shift compensation after dural opening in open cranial surgery, eliminating user intervention and expertise requirements.

Intraoperative stereovision (iSV) integration: Utilized iSV images to capture high-resolution surface deformation data, which was processed by deep learning-based segmentation (FastSAM) and registered with preoperative MRI using vessel and sulcus features.

Two-step registration process: Employed translation-only cross-correlation for global alignment and Demons deformable registration for local nonrigid deformation between iSV and preoperative MRI surfaces.

Biomechanical modeling: Assimilated extracted nonrigid cortical displacements into a finite element model to estimate whole-brain deformation and generate updated MR images (uMR).

Accuracy improvement: Achieved significant reduction in target registration error (TRE) from 6.2 ± 1.2 mm (pMR) to 1.9 ± 1.0 mm (uMR), with overall mean computational time of 3.9 ± 0.6 minutes and no user intervention.

Robustness and efficiency: System was robust across a range of surgical conditions (lesion type, craniotomy size, brain shift magnitude), and performance was not significantly affected by these variables.

Limitations: Current system requires clear iSV images (free of instruments/blood), is limited to initial post-dural opening updates, and surface accuracy was primarily evaluated; further development is needed for autonomous updates during resection and deeper structure validation.

Potential for broad adoption: Elimination of user dependency and minimal workflow interruption suggest strong potential for integration into routine open cranial 

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Clinical Outcomes of Decompressive Spine Surgery for Painless Cervical Myelopathy

Neurosurgery 98:161–173, 2026

This multicenter retrospective study analyzes 407 patients from the Michigan Spine Surgery Improvement Collaborative who underwent decompressive surgery for cervical spondylotic myelopathy presenting without neck or arm pain. Patient-reported outcomes (mJOA, PROMIS PF, EQ-5D) and clinical endpoints were assessed at baseline, 90 days, 1 year, and 2 years to quantify functional and quality-of-life changes after surgery.

Results show modest but clinically meaningful improvements in function and quality of life for a subset of patients, with peak MCID rates at one year and sustained patient satisfaction above 80% at two years. Severe preoperative myelopathy predicted worse immediate disposition and higher readmission, although some severe cases still achieved early functional gains.

Painless Cervical Myelopathy (CSM) Surgery: Decompressive spine surgery in patients with CSM but without neck or arm pain led to clinically significant improvements in myelopathic symptoms and physical function for a modest proportion of patients.

Quality of Life Gains: Surgery resulted in increased quality of life, with mean EQ-5D scores higher at all postoperative time points compared to baseline, and over 80% of patients reported sustained satisfaction up to two years after surgery.

Severity-Dependent Outcomes: Patients with severe myelopathy had worse immediate surgical outcomes (lower rates of discharge to home, higher 90-day readmission) and lower quality of life at two years compared to those with mild myelopathy.

Incidence of Postoperative Pain: Despite presenting without pain, 20% of patients developed persistent postoperative neck pain and 14% developed arm pain at two years, rates comparable to those seen in typical CSM surgery cohorts.

Functional Improvement Metrics: At one year, 49% achieved clinically meaningful improvement in physical function (PROMIS PF), 36% in mJOA, and 42% in quality of life (EQ-5D); these improvements were most pronounced at one year and declined by two years for some metrics.

Surgical Approach Differences: Anterior approaches were associated with higher postoperative satisfaction and lower rates of complications like dysphagia compared to posterior or combined approaches.

Study Limitations: Limitations include lack of radiological data, possible misclassification of myelopathy severity, and significant loss to follow-up, affecting long-term outcome interpretation.

Clinical Implication: Surgery may halt progression and provide functional and quality of life benefits even in painless CSM, but patient selection remains challenging and further objective, randomized studies are needed.

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Lumbar Multifidus Intramuscular Fat Concentrations are Associated With Recovery Following Decompressive Surgery for Lumbar Spinal Stenosis

Spine 2026;51:25–33

This longitudinal cohort study investigates whether preoperative intramuscular fat (IMF) in lumbar paraspinal muscles predicts five-year recovery and surgical success after decompressive surgery for lumbar spinal stenosis causing intermittent neurogenic claudication. Using automated MRI segmentation and quantitative IMF thresholds, outcomes included global perceived effect, Zurich Claudication Questionnaire-based surgical success, pain VAS, and disability scores.

Key findings show lower preoperative multifidus IMF (but not erector spinae IMF) was associated with higher rates of perceived recovery, surgical success, and reduced long-term disability over five years. No consistent relationship was found between IMF and leg or back pain trajectories; results were adjusted for age, BMI, sex, smoking, reoperation, and surgical technique.

Lumbar multifidus intramuscular fat (IMF): Lower preoperative IMF in the lumbar multifidus muscle is associated with higher rates of perceived recovery and surgical success after decompression surgery for lumbar spinal stenosis (LSS) over a five-year period.

Erector spinae IMF: Preoperative IMF levels in the erector spinae muscle are not significantly associated with recovery or surgical success following LSS surgery.

Disability outcomes: Patients with nonsevere IMF in the right lumbar multifidus experience less postoperative disability for up to five years compared to those with severe IMF.

Pain outcomes: No significant association exists between preoperative paraspinal IMF (either muscle) and the clinical course of leg or back pain intensity after surgery.

IMF quantification method: Automated MRI-based quantification and categorization of IMF (<50% = nonsevere, ≥50% = severe) using computer vision models enables objective assessment of paraspinal muscle health.

Prognostic value: Assessing lumbar multifidus IMF preoperatively can improve prediction of which patients are at risk for poor recovery and help tailor individual interventions.

Study limitations: Missing data (up to 32% at five years), dichotomized IMF classification, and limited field-of-view for some muscles may affect precision; more detailed and larger studies are needed.

Clinical implication: Routine IMF assessment may enhance clinical decision-making and rehabilitation strategies for patients undergoing lumbar decompressive surgery.

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Skull Base Anatomy Presented in 360° Photogrammetry 3-Dimensional Models

Operative Neurosurgery 30:124–136, 2026

This article presents the creation of seven photorealistic 360° photogrammetric 3D models of the central skull base derived from stepwise dissections of a formalin-fixed, vessel-injected cadaveric head. The workflow—dissection stages, smartphone-based image capture, cloud photogrammetry, refinement in Blender, and VR/MR upload—enables immersive visualization of cranial nerves, ICA/vertebral segments, and regional anatomy.

The models offer progressive exocranial-to-endocranial perspectives for education and preoperative planning, highlighting cavernous sinus, infratemporal and pterygopalatine fossae, petrous bone, and foraminal relationships. Limitations include a single-specimen dataset, color variations from fixation, and resolution constraints in deep cavities; nevertheless, the freely accessible VR models complement traditional dissection and anatomical atlases.

360° Photogrammetric 3D Models: Realistic, photogrammetry-based 3D models of the central skull base were created from cadaveric dissections, offering immersive 360° visualization of complex neuroanatomical structures for enhanced spatial understanding.

Stepwise Dissection and Scanning: Seven progressive anatomical models were generated by systematically dissecting and scanning a formalin-fixed, vessel-injected head specimen, documenting both exocranial and endocranial perspectives.

Key Structures Visualized: The models detail the courses of cranial nerves, major vessels (including all internal carotid artery segments), skull base foramina, infratemporal and pterygopalatine fossae, paranasal sinuses, and deep neck spaces.

Technical Workflow: High-resolution images were captured using a smartphone multi-camera system, processed via cloud-based photogrammetry, refined in 3D software, and made accessible through web, VR, and MR platforms.

Educational Value: The interactive models allow customizable, layered exploration of anatomy, overcoming limitations of traditional 2D images and static atlases, and are freely accessible for educational and preoperative planning purposes.

Limitations: The study used a single specimen, which may not represent anatomical variants; image quality in deep/narrow regions could be further improved with advanced imaging and fixation techniques.

Broad Accessibility: Smartphone-based and cloud photogrammetry methods make high-resolution anatomical modeling more accessible and less resource-intensive, facilitating widespread dissemination.

Conclusions: 360° photorealistic 3D models significantly enhance comprehension of skull base anatomy and are a valuable adjunct to traditional teaching, with potential to improve neurosurgical training and patient outcomes.

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A pilot randomized control trial comparing posterior paramedian versus midline incisions for interbody fusions of the lumbar spine

The Spine Journal 26 (2026) 85−93

This single-center pilot randomized controlled trial compares posterior midline versus posterior paramedian (Wiltse/minimally invasive) approaches for 1–2 level lumbar interbody fusions, assessing feasibility, infection rates, and reoperation. One hundred-one patients were randomized, with reported differences: higher deep infection (9.6% vs 4.1%) and greater reoperation rates (25% vs 6.1%) in the midline group, alongside improvements in PROMs for both groups.

Methods, perioperative care, and outcome measures are detailed, including CDC-defined deep infection, PROMs (ODI, SF-12, EQ-5D, VAS), and feasibility metrics for a multicenter RCT. The authors conclude the pilot supports a larger trial, recommend an interim analysis for reoperation differences, and outline limitations related to single-surgeon data, recruitment disruptions, and clustering effects.

Pilot RCT Findings: A single-center pilot randomized controlled trial compared posterior paramedian and midline incisions for lumbar interbody fusion, finding potential differences in deep infection and reoperation rates, with both groups showing improvement in patient-reported outcomes.

Infection Rates: Deep infection occurred in 9.6% of midline patients versus 4.1% in the paramedian group within 3 months post-surgery.

Reoperation Rates: 25% of midline patients required revision surgery compared to 6.1% in the paramedian group during follow-up.

Patient Outcomes: Both surgical approaches led to improvements in disability, pain, and quality of life scores at 6–18 weeks and 1 year postoperatively, with slightly greater improvements noted in the paramedian group.

Intraoperative Metrics: The paramedian group had lower average blood loss (268ml vs. 313ml) and a shorter average hospital stay (3.3 vs. 4.2 days) compared to the midline group.

Feasibility: The trial demonstrated high protocol adherence, low loss to follow-up, and good participant acceptance, supporting the feasibility of a larger multicenter RCT.

Limitations: The pilot was limited by single-center design, small sample size, protocol violations, and short follow-up; results may not be generalizable until confirmed by a larger trial.

Next Steps: The pilot data will inform sample size calculations and study design for a multicentered RCT to clarify whether paramedian approaches offer significant clinical advantages over midline incisions.

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Long-Term Mortality of Patients With Head Injuries—A 10-Year Follow-up Study With Population Controls Study Performed at Tampere University Hospital

Neurosurgery 98:105–114, 2026

This study reports a 10-year follow-up comparing survival and causes of death between 1,930 patients treated for head injuries at a Finnish university hospital and 9,605 matched population controls. After excluding deaths within the first year, patients had a hazard ratio of 1.84 for mortality, with excess deaths concentrated in the first five years and elevated unintentional/traumatic and alcohol-related causes.

Multivariable analysis found age, male sex, pre-existing conditions, chronic alcohol use, and substance abuse—rather than injury severity or CT-positivity—were independently associated with reduced survival, though greater TBI severity remained linked to additional mortality risk when comparing patient severity subgroups to their matched controls.

Long-term Mortality: Patients with head injuries have significantly reduced long-term survival compared to matched population controls, with a hazard ratio (HR) for death of 1.84 after excluding those who died in the first year post-injury.

Acute vs. Long-term Risk: Death rates are notably higher among patients with head injuries for up to 5 years after injury, then approach control levels thereafter.

Causes of Death: Unintentional and traumatic causes (9.6% vs 4.4%) and alcohol-related causes (8.4% vs 1.9%) are significantly more common among head injury patients than controls.

Patient Characteristics: Age, male sex, pre-existing conditions, chronic alcohol use, and regular substance abuse are independently associated with decreased survival, whereas injury severity and CT findings are not significant predictors in multivariate analysis.

TBI Severity: Even patients with no documented traumatic brain injury (TBI) have reduced survival compared to controls; increasing TBI severity is associated with additional mortality risk.

Lifestyle and Pre-existing Factors: Much of the reduced survival is linked to patient characteristics and lifestyle factors (such as substance abuse), not solely to injury-related factors.

Immediate Causes of Death: Aspiration pneumonia and epileptic causes are significantly overrepresented as immediate causes of death in head injury patients who survive more than one year.

Control Group Limitations: Use of population controls and lack of detailed control data may overestimate associations between head injury and mortality due to unmeasured confounders.

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Functional status in long-term survivors after mapping-guided surgery for diffuse low-grade glioma

J Neurosurg 144:139–150, 2026

This clinical study reports long-term functional outcomes in 103 consecutive patients with diffuse low-grade glioma who underwent mapping-guided resections and were followed for at least 15 years. Key findings include high overall survival (83.5%), mean postoperative KPS of 94.8, and 90% return-to-work rate, with low permanent neurological morbidity across 205 resections.

Comparative analysis shows patients who sustained employment had smaller pre/postoperative tumor volumes, greater extent of resection (including more supratotal resections), and less exposure to radiotherapy. The data support early maximal safe resection and postponement of radiotherapy to preserve long-term functional status and professional activity.

Functional Preservation: Long-term survivors of diffuse low-grade glioma (LGG) surgery had high rates of preserved functional status, with 90.7% of surviving patients maintaining a Karnofsky Performance Scale (KPS) score ≥ 80 after an average of 18.2 years follow-up.

Return to Work: 90% of patients were able to return to work after mapping-guided resection, and maintaining professional activity was strongly associated with higher preoperative KPS and greater extent of resection (EOR).

Extent of Resection (EOR): Greater EOR, particularly supratotal or total resections, correlated with better long-term functional outcomes and higher rates of continued employment.

Radiation Therapy Impact: Early or any radiotherapy (RT) was linked to lower rates of return to work and a reduced proportion of patients with KPS ≥ 80 at last follow-up, while chemotherapy did not show this negative association.

Timing of Surgery: Early surgery at diagnosis, especially in patients with higher KPS and smaller tumor volume, increased the chance for maximal resection and long-term preservation of functional status.

Low Neurological Morbidity: Permanent postoperative neurological deficits were rare (1.5% after 205 resections), supporting the safety of maximal resection with intraoperative mapping.

Malignant Transformation: The risk of malignant transformation was lower in patients with greater EOR and those who continued to work, suggesting oncological benefit from radical resection.

Adjuvant Therapy Strategy: A wait-and-watch strategy after maximal safe resection, postponing adjuvant treatments unless necessary, helped preserve long-term quality of life and autonomy.

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Guidelines for the Diagnosis and Clinical Management of Cavernous Malformations of the Brain and Spinal Cord

Neurosurgery 98:3–22, 2026

These guidelines present updated, evidence-based recommendations for diagnosing and managing cavernous malformations (CMs) of the brain and spinal cord, produced by an expert multidisciplinary panel convened by the Alliance to Cure Cavernous Malformation. The document summarizes systematic literature review methods, evidence ratings, and 53 consensus recommendations across epidemiology, genetics, imaging, neurosurgery, and neurology.

Key clinical guidance addresses diagnostic MRI protocols, genetic testing for familial CM (KRIT1/CCM2/PDCD10), surgical/radiosurgical indications including pediatric and geriatric considerations, seizure and headache management, and lifestyle and medication factors potentially affecting hemorrhage risk. Recommendations highlight evidence limitations and prioritize further research.

Diagnosis: MRI with susceptibility-weighted sequences is the gold standard for diagnosing cavernous malformations (CMs); CT may be used in emergencies, but MRI is preferred for follow-up and detailed assessment.

Genetic Testing: Genetic testing for KRIT1 (CCM1), CCM2, and PDCD10 (CCM3) is recommended for individuals with multiple CMs, a family history, or suspected familial CM (FCM); founder mutations exist in certain populations.

Hemorrhage Risk: Annual risk of symptomatic intracranial hemorrhage (ICH) from CMs ranges from 0.7% to 7.5%, with higher risk for recurrent bleeds and in familial cases, especially with CCM3 mutations.

Surgical Management: Surgery is generally reserved for symptomatic, accessible CMs or those causing drug-resistant epilepsy; conservative management is preferred for asymptomatic or deep/eloquent area lesions unless recurrent bleeds occur.

Medical Management: Antiseizure medication is recommended after a first CM-related seizure; standard migraine therapy applies for nonhemorrhagic CMs, and nonaspirin NSAIDs can be used cautiously.

Pregnancy: Pregnancy does not increase the risk of CM hemorrhage compared to nonpregnant states; MRI without contrast is advised for new neurological symptoms during pregnancy.

Medication Risks: Antithrombotic agents (e.g., aspirin) do not increase and may actually lower CM hemorrhage risk, while female hormones may increase risk; thrombolytic use remains controversial and should be considered on a case-by-case basis.

Lifestyle and Emerging Therapies: Vitamin D supplementation, aerobic activity, and a diet low in processed foods are reasonable lifestyle recommendations; propranolol and statins show potential but lack definitive evidence for reducing hemorrhage risk.

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Single-Fraction Stereotactic Radiosurgery as Primary Management of Sporadic Meningiomas: A 25-Year Cohort Study

Neurosurgery 97:1267–1274, 2025

This study reports long-term outcomes of single‑fraction Gamma Knife stereotactic radiosurgery (SRS) as primary treatment for 653 sporadic intracranial meningiomas in 616 patients over a 25‑year period. With median margin dose 15 Gy and median imaging follow-up 6.3 years, progression‑free survival was excellent (99.8% at 5 years, 99.0% at 10 years), and raw tumor control reached 98.6%.

Treatment‑related neurological sequelae were uncommon (1.8% permanent/intervention), though larger tumor volume, higher V12, and greater number of isocenters increased complication risk. The authors conclude single‑fraction SRS at studied doses offers high long‑term control for small‑to‑medium sporadic meningiomas, emphasizing careful patient selection.

Stereotactic Radiosurgery (SRS) Effectiveness: Single-fraction SRS is highly effective as a primary treatment for sporadic, small- to medium-volume intracranial meningiomas, achieving a 99% tumor control rate at 10 years and 93% at 15 years progression-free survival (PFS).

Low Permanent Morbidity: The risk of permanent treatment-related neurological complications is low (1.8%), with most side effects being temporary or minor.

Key Predictors of Outcome: Larger tumor volume is the main predictor of both tumor progression and treatment-related complications, emphasizing the importance of patient selection for SRS.

Radiosurgical Parameters: Increased number of isocenters, higher 12-Gy volume (V12), larger tumor volume, and lower maximal dose are associated with higher risk of treatment-related complications.

Comparison to Observation: SRS provides superior tumor control compared to observation in patients with incidentally discovered, asymptomatic meningiomas, with similar rates of new neurological deficits.

Radiation Dose Recommendations: A median margin dose of 13–15 Gy balances long-term tumor control and risk of complications; doses below 12 Gy may increase recurrence risk, while higher doses increase morbidity.

Biological Effective Dose (BED): In this cohort, higher BED was not predictive of improved PFS, likely due to the already high dosing protocol; however, other studies suggest BED can be a useful predictor when a wider dose range is used.

Limitations: The study is retrospective and single-institution, with potential selection bias and incomplete follow-up; findings may not generalize to syndromic or radiation-induced meningiomas.

 

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Operative Microscope In-Field Visualization of Confocal Laser Endomicroscopy Interface (Zeiss CONVIVO )

Operative Neurosurgery 29:860–864, 2025

This study evaluates integrating the Zeiss CONVIVO confocal laser endomicroscopy interface into the operative microscope heads-up display to allow simultaneous visualization of the surgical field and real-time confocal laser endomicroscopy (CLE) images. A randomized cohort of 22 intra-axial tumor surgeries showed shorter CLE usage times, fewer total captures, and a trend toward higher usable-image proportion with heads-up integration.

The integration improved intraoperative ergonomics by reducing probe motion artifacts and image noninterpretability, streamlining workflow, and decreasing operative time while preserving diagnostic utility of CLE for margin assessment in gliomas and other brain lesions.

Confocal Laser Endomicroscopy (CLE): Provides real-time, in vivo microscopic imaging of brain tumors during neurosurgery, enabling identification of tumor margins without the need for traditional tissue extraction or frozen section analysis.

Zeiss CONVIVO® System: A CLE device recently introduced in neurosurgery, proven reliable for both ex vivo and in vivo applications, and undergoing further clinical refinement.

Technical Challenge: Standard CLE use requires the surgeon to shift attention from the operative field to a separate screen to assess image quality, potentially causing motion artifacts, prolonging surgery, and increasing the number of unusable images.

Heads-Up Display Integration: Visualization of the CONVIVO® interface was integrated as a picture-in-picture display inside the operative microscope, allowing simultaneous monitoring of the surgical field and CLE images without diverting gaze.

Study Findings: Use of the heads-up display significantly reduced CLE employment time (mean 61.1 vs. 201.6 seconds; P = .01), decreased the total number of images acquired, and increased the proportion of usable images, though the latter was not statistically significant (P = .06).

Workflow Efficiency: Direct intraoperative feedback enabled by the heads-up display led to fewer motion artifacts, more efficient image acquisition, and reduced overall operative time.

Clinical Implications: The integration supports more efficient and accurate intraoperative tumor assessment, potentially improving the extent of resection, especially in gliomas, and reducing reliance on frozen sections.

Limitations and Future Directions: Further refinement is needed for effortless image acquisition; artificial intelligence for artifact reduction and real-time interpretation by neurosurgeons are potential future improvements.

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Integrated insular phenotype (IIP) versus Berger–Sanai and Yasargil classifications: comparative prognostic value in surgery of insular gliomas

Acta Neurochirurgica (2025) 167:324

This study compares the Integrated Insular Phenotype (IIP), a three-level ordinal topographic classification of insular gliomas, with Berger–Sanai and Yasargil systems to evaluate prognostic performance for extent of resection, seizure control, and persistent neurological deficit at 90 days. Using retrospective analysis of 167 surgically treated patients, logistic regression and model metrics (AUC, AIC, LR χ2) assessed associations between classification complexity and outcomes.

Results show increasing IIP complexity strongly predicted lower resectability, poorer seizure control, and higher persistent deficit risk; IIP produced more stable odds ratios, lower AIC, and higher LR χ2 than traditional systems. The authors propose IIP as a practical risk-stratification tool to balance oncological radicality and functional safety, recommending multicenter prospective validation and integration with molecular and intraoperative technologies.

Integrated Insular Phenotype (IIP): An ordinal classification system for insular gliomas that incorporates tumor topographic complexity and multizonal involvement, outperforming traditional Berger–Sanai and Yasargil systems in prognostic accuracy for surgical outcomes.

Prognostic Value: IIP demonstrates superior and more stable associations with key surgical outcomes—extent of resection, seizure control, and persistent neurological deficit at 90 days—compared to Berger–Sanai and Yasargil classifications, as shown by higher informativeness, lower AIC, and more reproducible odds ratios.

Surgical Complexity: Higher IIP complexity (IIP-M) is linked to reduced likelihood of total/subtotal resection, poorer seizure control, and increased risk of persistent neurological deficits, while simpler phenotypes (IIP-L) are associated with more favorable outcomes.

Traditional Classifications: Berger–Sanai and Yasargil systems provide limited prognostic value; Berger–Sanai yields high but unstable odds ratios with wide confidence intervals, while Yasargil offers consistent but less discriminative results.

Clinical Implications: IIP can guide individualized surgical strategies by balancing oncological radicality against functional safety, supporting the principle of maximal safe resection and informing risk stratification.

Seizure Outcomes: Multizonal and widespread IIP phenotypes (IIP-M) are associated with poorer postoperative seizure control, reflecting the challenge of eliminating diffuse epileptogenic networks.

Study Limitations: The findings are based on a single-center retrospective cohort; external validation and integration with molecular, histopathological, and neurocognitive factors are needed for broader applicability.

Future Directions: Prospective multicenter validation, integration with intraoperative technologies, and use of AI/ML for risk stratification and personalized planning are recommended to enhance the utility of IIP in clinical practice

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Randomized controlled trials comparing cervical disc arthroplasty and anterior cervical discectomy and fusion outcomes in degenerative spine disease: a systematic review and meta-analysis

J Neurosurg Spine 43:703–716, 2025

This systematic review and meta-analysis synthesizes randomized controlled trials comparing cervical disc arthroplasty (CDA) with anterior cervical discectomy and fusion (ACDF) for degenerative cervical disc disease. Across 25 RCTs (4530 patients), CDA demonstrated higher overall and neurological success, reduced adjacent-segment disease and fewer reoperations, but increased heterotopic ossification and longer operative times.

The authors performed multilevel meta-analysis and meta-regression to explore heterogeneity, finding myelopathy inclusion and follow-up completeness influenced results; sensitivity analyses excluding industry-funded trials showed consistent findings. Conclusions emphasize CDA’s potential benefits for selected patients while recommending longer-term and subgroup-specific trials.

Cervical Disc Arthroplasty (CDA) vs. Anterior Cervical Discectomy and Fusion (ACDF): CDA shows comparable or potentially greater overall and neurological success rates compared to ACDF for degenerative cervical spine disease.

Motion Preservation: CDA preserves cervical spine range of motion at the operated level, while ACDF is associated with loss of motion and potentially increased risk of adjacent segment degeneration (ASD).

Adjacent Segment Disease (ASD): CDA is associated with a significantly lower rate of ASD compared to ACDF, suggesting a protective effect against degeneration of adjacent spinal segments.

Reoperation Rates: CDA results in lower total reoperation rates compared to ACDF, indicating fewer subsequent surgical interventions.

Heterotopic Ossification (HO): CDA has a significantly higher rate of HO, a complication where bone forms in soft tissue, which can potentially reduce the motion-preserving benefit of the procedure.

Operative Time: CDA procedures are associated with significantly longer operative times than ACDF, with no significant difference in blood loss or hospital length of stay between the two techniques.

Pain and Disability Outcomes: No significant differences were found between CDA and ACDF in terms of improvement in arm pain, neck pain, or disability scores (Neck Disability Index) as measured by patient-reported outcomes.

Patient Selection: The benefits of CDA over ACDF are most applicable to patients with 1-2 level degenerative disease, preserved cervical alignment, and no significant instability or deformity; findings may not generalize to more complex cases.

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Role of surgical treatment of intracranial aneurysms in the era of endovascular therapy: a review

Neurosurg Focus 59(6):E2, 2025

This review evaluates the contemporary role of microsurgical clipping versus endovascular treatment (EVT) for intracranial aneurysms, comparing long-term durability, complication profiles, and anatomical or patient factors that guide modality selection. It synthesizes trial data (ISAT, BRAT), meta-analyses, and location-specific outcomes to highlight differences in occlusion, retreatment, and morbidity.

The article also outlines practical considerations—hybrid strategies, cerebral bypass, training needs, economics, and global disparities—arguing for individualized, multidisciplinary decision-making and preserving microsurgical expertise despite growing EVT adoption.

Treatment Goals: Exclusion of intracranial aneurysms from circulation while preserving parent vessels and neural function remains the primary objective; both endovascular treatment (EVT) and microsurgical clipping are core modalities.

Long-term Outcomes: Microsurgical clipping offers greater durability and lower rates of recurrence, rebleeding, and retreatment compared to EVT, which has higher retreatment rates despite lower short-term morbidity.

Procedure Selection: EVT is generally preferred for older patients and posterior circulation aneurysms, while microsurgery is favored in younger patients, those with hematomas, mass effect, and aneurysms of the middle cerebral and pericallosal arteries.

Aneurysm Location: Surgical clipping achieves higher occlusion and lower recurrence, especially for anterior circulation, middle cerebral artery, and complex aneurysms; EVT is more suitable for posterior circulation and anatomically challenging cases.

Complications and Adjuncts: Microsurgery allows for evacuation of hematomas and cisternal blood (reducing vasospasm and hydrocephalus), while EVT avoids craniotomy risks but may induce mechanical vasospasm and requires antiplatelet therapy.

Hybrid and Advanced Techniques: Hybrid approaches (combining EVT and surgery) and cerebral bypass remain essential for complex, giant, or recurrent aneurysms not amenable to standard treatments.

Cost and Access: Microsurgical treatment incurs lower overall healthcare costs than EVT; global disparities exist, with surgical clipping dominating in low-resource settings due to limited endovascular infrastructure.

Decision-Making: Optimal management requires individualized, multidisciplinary evaluation considering patient factors, aneurysm characteristics, and resource availability; no single factor should solely dictate treatment choice

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Recurrence of initial angiographic occlusion in intracranial dural arteriovenous fistulas

J Neurosurg 143:1530–1538, 2025

This clinical study analyzes recurrence after angiographic cure of intracranial dural arteriovenous fistulas (DAVFs) using a single-center DREAM-INI cohort of 510 patients. It reports an overall recurrence rate of 8.0%, estimated cumulative recurrence of 13.9% at 36 months and 24.1% at 105 months, and an annual recurrence risk of 6.2%, with most recurrences occurring within 15 months but some delayed beyond 10 years.

The paper identifies independent risk factors including age <45 years, transverse–sigmoid sinus location, multiple fistulae, pial arterial supply, and venous congestion, distinguishes in situ versus remote-site recurrence, explores pathophysiologic mechanisms (venous hypertension, incomplete embolization, angiogenesis), and recommends angiographic follow-up beyond one year for high-risk cured patients.

Recurrence Rate: The overall recurrence rate of intracranial dural arteriovenous fistulas (DAVFs) after initial angiographic cure was 8.0%, with estimated recurrence rates of 13.9% at 36 months and 24.1% at 105 months; the annual recurrence risk was 6.2%.

Types of Recurrence: DAVF recurrence can be classified as in situ recurrence (at the original site) or remote site recurrence (at a different location); both are closely linked to unresolved venous hypertension and previously masked portions of the fistula.

Timing of Recurrence: Most recurrence events (76.6%) occurred within 15 months after initial cure, but delayed recurrences were observed, including cases more than 3 years and up to 10 years later.

Risk Factors: Key risk factors for recurrence included age younger than 45 years, transverse–sigmoid sinus location, multiple fistulae, pial arterial supply, and venous congestion.

Borden Classification: Recurrence was more frequently observed in Borden type II DAVFs, whereas Borden type III DAVFs had a lower recurrence rate when complete occlusion of the proximal draining vein was achieved.

Treatment Implications: Almost all recurrences occurred after endovascular therapy, highlighting the importance of ensuring complete occlusion of the draining vein to minimize recurrence risk.

Clinical Symptoms: There was no clear correlation between clinical symptoms and DAVF recurrence; many recurrences were asymptomatic, emphasizing the need for routine angiographic follow-up.

Follow-Up Recommendation: All patients with cured DAVFs, especially those with identified risk factors, should undergo angiographic follow-up beyond 1 year to detect and manage possible recurrences.

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The impact of Roussouly sagittal profile changes on postoperative outcomes

J Neurosurg Spine 43:609–615, 2025

This clinical study examines postoperative changes in Roussouly sagittal spinal profiles among 525 adult spinal deformity (ASD) patients and evaluates how shifts between Roussouly types influence mechanical complications and patient-reported outcomes up to two years after fusion surgery. Methods include radiographic classification (current SS-based and theoretical PI-based), HRQOL measures (ODI, SRS-22r, EQ-5D), and multivariate regression to link type changes with PJK/PJF and MCID attainment.

Key findings show 39–59% of patients experienced postoperative Roussouly shape changes, with certain transitions (R1→R2, R2→R4, R3→R4) associated with higher proximal junctional kyphosis/failure risk and R4→R3 linked to greatest mechanical complication risk. R2-mismatched patients had poorer ODI improvement and higher pelvic nonresponse, suggesting Roussouly matching should inform ASD surgical planning.

Roussouly Classification Changes: Postoperative changes in Roussouly sagittal profile are common after adult spinal deformity (ASD) surgery, with 39% of patients experiencing a change in Roussouly type at 6 weeks post-op; type 1 (R1) patients had the highest rate of change (59%) and type 4 (R4) the lowest (26.7%).

Mechanical Complication Risk: Certain Roussouly type changes significantly increase the risk of proximal junctional kyphosis (PJK) and mechanical complications, especially transitions from R1 to R2, R2 to R4, R3 to R4, and R4 to R3.

Health-Related Quality of Life (HRQOL): Overall, Roussouly type changes were not associated with significant differences in minimum clinically important difference (MCID) achievement for SRS-22r scores up to 2 years, except for a lower rate of ODI MCID attainment in R2-mismatched patients.

Surgical Invasiveness and Deformity Severity: R1 patients had the most severe baseline deformity and underwent more extensive surgery, which may contribute to higher rates of postoperative Roussouly type changes.

Matching Theoretical Roussouly Type: Only 48% of patients matched their theoretical (PI-based) Roussouly type postoperatively; those who matched, especially in the R2 group, had better functional outcomes and lower rates of pelvic nonresponse (PNR).

Clinical Implications: Maintaining or restoring the original Roussouly type during ASD surgery may reduce the risk of mechanical complications and improve early functional outcomes, particularly for R2 patients.

Limitations: The study was retrospective, single-center, and limited to 2-year follow-up, which may affect generalizability and long-term conclusions.

Surgical Planning: Accounting for Roussouly type changes and known risk factors (e.g., osteoporosis, advanced age) during surgical planning may help decrease postoperative complications.

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The Association of Area Deprivation Index and Spine Surgery Outcomes: A Systematic and Narrative Review

Operative Neurosurgery 29:775–784, 2025

This systematic review examines the relationship between neighborhood-level socioeconomic disadvantage, measured by the Area Deprivation Index (ADI), and outcomes after various spine surgeries. Ten North American observational studies (56,925 patients) indicate higher ADI is associated with increased readmissions, emergency visits, longer lengths of stay, higher costs, and worse patient-reported outcomes for cervical and lumbar procedures.

The review outlines potential mechanisms—limited health literacy, barriers to follow-up, comorbidity control, and access deficits—and proposes targeted interventions across education, income/employment, housing, and household support to mitigate disparities and improve perioperative optimization and outcomes.

Area Deprivation Index (ADI): ADI is a validated, neighborhood-level measure of socioeconomic disadvantage, incorporating 17 variables across education, income/employment, housing, and household characteristics, with scores ranked from 0 (least disadvantaged) to 100 (most disadvantaged).

Association with Spine Surgery Outcomes: High ADI is linked to worse outcomes after spine surgery, including higher rates of postoperative readmissions, complications, emergency room visits, longer hospital stays, and poorer patient-reported outcomes (PROs).

Cervical Spine Surgery: Increased ADI is associated with higher costs of care, increased surgical utilization, and longer hospital length of stay after anterior cervical discectomy and fusion (ACDF); some studies also report increased likelihood of 30-day readmission, though not always statistically significant.

Lumbar Spine Surgery: High ADI predicts worse preoperative pain, function, depression, and anxiety scores; patients with high ADI experience greater rates of complications (e.g., respiratory failure), longer hospital stays, increased emergency visits, higher costs, and are less likely to achieve clinically meaningful improvements postoperatively.

Mechanisms of Disparity: Poor health literacy, reduced access to primary and follow-up care, barriers to transportation, and poor control of comorbidities are key mechanisms by which high ADI leads to worse surgical outcomes.

Potential Interventions: Targeted interventions addressing education (health literacy outreach, transitional care), income/employment (public assistance, nutrition programs), housing (medical-legal partnerships, transitional housing), and household resources (home health, internet access, transportation assistance) may help mitigate disparities for high ADI patients.

Limitations: Evidence is limited by heterogeneity of included studies, moderate risk of bias, small sample sizes for some subgroups, and lack of generalizability across all spine surgery types.

Future Directions: ADI can serve as a prognostic tool for identifying at-risk patients; further research should validate these associations and evaluate the effectiveness of targeted interventions to improve spine surgery outcomes in disadvantaged populations.

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Optimal imaging follow-up strategies for conservatively managed cerebral cavernous malformations: a cost-effectiveness analysis

J Neurosurg 143:1555–1566, 2025

This study evaluates cost-effectiveness of MRI surveillance intervals for conservatively managed cerebral cavernous malformations (CCMs) using a Markov model and Monte Carlo simulations. It compares 0.5-, 1-, 2-, and 3-year follow-up strategies for brainstem versus nonbrainstem CCMs, calculating lifetime costs, QALYs, and net monetary benefit from a US societal perspective.

Results indicate annual MRI is most cost-effective for brainstem CCMs, while a 3-year MRI interval is preferred for nonbrainstem CCMs, with findings robust to sensitivity analyses that varied hemorrhage rates, mortality, and MRI costs. The authors emphasize individualized follow-up based on symptoms, Zabramski grade, family history, and lesion multiplicity, and note model limitations and US-centric cost data.

Optimal MRI Follow-up for Brainstem CCM: Annual MRI follow-up (every 1 year) is the most cost-effective strategy for conservatively managed, unruptured brainstem cerebral cavernous malformations (CCM), balancing cost and quality-adjusted life years (QALYs).

Optimal MRI Follow-up for Nonbrainstem CCM: MRI follow-up every 3 years is the most cost-effective approach for nonbrainstem CCM, with less frequent imaging justified by lower rupture and rehemorrhage rates.

Markov Model and Monte Carlo Simulation: A decision-analytic Markov model with Monte Carlo simulations was used to compare different MRI follow-up intervals (0.5, 1, 2, and 3 years) for both brainstem and nonbrainstem CCM, incorporating costs, effectiveness (QALYs), and net monetary benefit (NMB).

Key Drivers of Cost-effectiveness: The cost-effectiveness of follow-up strategies is highly sensitive to annual rates of CCM rupture, mortality after rupture, and the cost of MRI; higher hemorrhage or mortality rates favor more frequent imaging.

Individualization of Follow-up: Follow-up intervals should be tailored based on lesion location, symptoms, prior hemorrhage, Zabramski grade, family history, and multiplicity, as higher-risk patients may benefit from closer surveillance.

Brainstem Lesion Risks: Brainstem CCMs have higher annual rupture (2.8%) and rehemorrhage rates (32.3%) compared to nonbrainstem lesions, resulting in greater disability and loss of quality of life, justifying more vigilant follow-up.

MRI Cost Thresholds: As the annual MRI cost increases above $6,581 for brainstem CCM and $8,995 for nonbrainstem CCM, less frequent MRI follow-up (every 2 years) becomes more cost-effective than the previously optimal intervals.

Limitations: The model does not distinguish between cerebellar and supratentorial nonbrainstem lesions, does not account for comorbidities or detailed imaging findings (e.g., Zabramski grade), and uses US-based cost data, which may limit generalizability to other healthcare settings.

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Institutional experience using the endoscopic endonasal approach for the treatment of 40 intracranial aneurysms: indications, outcomes, and technical considerations

J Neurosurg 143:1575–1587, 2025

This clinical series reviews 40 intracranial aneurysms treated via the endoscopic endonasal approach (EEA) over 20 years, outlining patient selection, operative techniques, reconstruction evolution, and outcomes. It emphasizes indications where EEA provides superior ventral access for paraclinoid and selected posterior circulation aneurysms, especially when endovascular therapy is unsuitable.

The report details complication rates—notably CSF leaks—and their temporal improvement, intraoperative adjuncts, follow-up imaging, illustrative cases, and statistical correlations identifying posterior location, age, and SAH as risk factors.

Endoscopic Endonasal Approach (EEA) Indications: EEA is reserved for carefully selected intracranial aneurysms—primarily medially projecting paraclinoidal/cavernous internal carotid artery (ICA) and posterior circulation aneurysms—especially when endovascular treatment is unsuitable and open surgery would risk cranial nerve or brain injury.

Advantages of EEA: Provides a direct ventral surgical corridor, enabling superior proximal/distal vascular control, avoiding brain retraction and cranial nerve manipulation, and facilitating treatment of concomitant sellar pathologies or multiple lesions in a single procedure.

Patient Selection and Outcomes: Out of 34 patients (40 aneurysms) over 20 years, most aneurysms treated were in the paraclinoid/cavernous ICA or posterior circulation; EEA was only used if it was considered safer than open or endovascular approaches, with less than 1% of aneurysm patients treated annually by EEA.

Complication Profile: The main complication was cerebrospinal fluid (CSF) leak (8 cases), particularly in posterior circulation or post-subarachnoid hemorrhage (SAH) cases; other complications included meningitis, clip exposure, lacunar infarcts, and transient cranial nerve palsies. No permanent cranial nerve deficits, visual loss, or procedure-related mortalities occurred since 2019.

Technical Evolution: Advancements in reconstruction techniques and instrumentation (e.g., dedicated endonasal clip appliers, multilayer closure) have reduced complications such as clip exposure and improved overall safety and outcomes over time.

Limitations of EEA: Not suitable for most anterior communicating artery (AcomA) aneurysms due to limited exposure and control; not feasible for revascularization procedures; requires a highly experienced, multidisciplinary team for optimal results.

Comparative Morbidity: EEA appears to reduce the risk of cranial nerve deficits and parenchymal injury compared to lateral (open) approaches, especially for midline lesions, but CSF leak remains the main limitation.

Clinical Recommendation: EEA should be considered only for selected cases where endovascular and open approaches are suboptimal, and only by experienced teams aware of the risks and reconstruction challenges, with all treatment options discussed in a multidisciplinary setting.

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To fuse or not to fuse: surgical strategies for recurrent lumbar disc herniation from a 16-nation study

J Neurosurg Spine 43:681–692, 2025

This international survey examines variability in surgical management of recurrent lumbar disc herniation across 515 spine surgeons from 16 countries, comparing redo discectomy versus various fusion techniques for six clinical scenarios. Findings reveal substantial inter- and intranational differences, specialty-related tendencies, and consensus only for simple first recurrences without back pain.

The study identifies key decision drivers—lumbar pain with radiculopathy and inflammatory disc disease—highlights gaps in high-level evidence, and calls for standardized research, registries, and improved training to harmonize indications and reduce practice heterogeneity.

Significant International Variability: Surgical strategies for recurrent lumbar disc herniation (LDH) vary widely among spine surgeons internationally, especially beyond the first recurrence without low back pain or instability, where decisions are more homogeneous.

Decision-Making Factors: Key factors influencing the choice for fusion over redo discectomy include the presence of low back pain with radiculopathy, radiological evidence of inflammatory disc disease, and the occurrence of second recurrences.

Surgeon Specialty Impact: Orthopedic surgeons are significantly more likely to propose procedures involving implants (fusion) compared to neurosurgeons, regardless of other demographic factors.

Country-Specific Patterns: Countries with low variability (e.g., Portugal, China, UK, Germany) favor posterior lumbar interbody fusion (PLIF/TLIF) and redo discectomy, while countries with high variability (e.g., France, Tunisia, US, Brazil) show more diverse approaches, including anterior and combined procedures.

Limited Influence of Experience and Practice Type: Duration of practice, annual surgical volume, and type of institution (public vs. private) generally do not significantly affect procedure choice, except in some first recurrence cases where public practitioners favor redo discectomy.

Lack of High-Level Evidence: There is a lack of strong, consistent evidence or guidelines favoring one surgical approach over another for recurrent LDH, contributing to the observed variability.

Patient and Surgeon Preferences: Decision-making is influenced by patient preferences, surgeon familiarity with techniques, desire for low-morbidity procedures, and adherence to literature, though economic factors play a lesser role.

Call for Standardization and Research: The findings highlight the need for high-quality studies, improved training, and international collaboration to reduce variability and improve decision-making in recurrent LDH surgery.

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Radiation exposure in XLIF surgery utilizing ultra-low radiation imaging with image enhancement software: a randomized controlled trial

The Spine Journal 25 (2025) 2692−2700

This randomized controlled trial evaluates ultra-low radiation imaging with image enhancement (mFluoro) versus conventional fluoroscopy during single-level XLIF lateral interbody fusion in 57 analyzed patients. Results show marked reductions in OR staff exposure (surgeon −72.1%, assistant −76.1%, scrub nurse −67.5%), lower patient DAP (−66.1%), fewer images, and shorter procedure times without increased complications.

The study used live dosimeters, standardized protocols, and optical reposition-assist technology (LessRay/PULSE) with Cios Spin. Findings support ULRI+IE as an effective strategy to decrease occupational and patient radiation during minimally invasive lateral spine surgery, noting limitations including lack of surgeon blinding and early learning-curve crossovers.

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