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.

 

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.

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

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.

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

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.

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.

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.

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.

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.

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.

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.

Nighttime surgery increases complication risk in chronic subdural hematoma: a population‑based cohort study

Acta Neurochirurgica (2025) 167:311

This population-based retrospective cohort study of 2,860 adults undergoing chronic subdural hematoma (CSDH) evacuation at a tertiary neurosurgical center (2006–2023) examines whether nighttime procedures increase postoperative risk. Nighttime surgery—defined by local shift boundaries—was independently associated with higher moderate-to-severe complications (OR 1.58), with risk peaking during final night-shift hours, while adjusted recurrence differences were not statistically significant.

The paper details standardized surgical protocols, staffing patterns, sensitivity analyses using alternative nighttime definitions, and multivariable models adjusting for comorbidity and neurological status. Authors conclude that when clinical stability permits, deferring CSDH evacuation to daytime hours may reduce significant complications, while acknowledging retrospective limitations and potential residual confounding.

Nighttime surgery: Undergoing chronic subdural hematoma (CSDH) surgery at night is independently associated with a higher risk of moderate-to-severe postoperative complications compared to daytime surgery (OR 1.58; 95% CI 1.04–2.37; p = 0.028).

Complication risk timing: The risk of complications increases gradually overnight and peaks during the final hours of the night shift, suggesting a circadian or fatigue-related effect.

Absolute risk increase: Nighttime surgery results in a 1.6% absolute increase in moderate-to-severe complications, with a number needed to harm (NNH) of 63, indicating a modest but clinically meaningful risk.

CSDH recurrence: Although recurrence rates were higher after nighttime surgery in unadjusted analysis, this difference was not statistically significant after adjusting for confounders (adjusted OR 1.28; 95% CI 0.98–1.65; p = 0.067).

Complication types: The most common moderate-to-severe complications include subdural empyema (1.4%), surgical site infection requiring revision (0.3%), and cerebral herniation (0.3%).

Clinical recommendation: When feasible and the patient is stable, deferring CSDH surgery to daytime hours is advised to minimize complication risk.

Prior research limitations: Previous studies were often underpowered, used inconsistent nighttime definitions, and found mixed results regarding the safety of nighttime CSDH surgery.

Study limitations: Retrospective design, possible unmeasured confounding, small differences in baseline severity, and limited generalizability to other healthcare settings with different resources or scheduling practices.

Lumbar Puncture or External Ventricular Drainage as Initial Treatment for Acute Hydrocephalus in Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 97:1308–1315, 2025

This two-center cohort study compares lumbar puncture (LP) versus external ventricular drainage (EVD) as initial treatments for acute hydrocephalus after aneurysmal subarachnoid hemorrhage, analyzing rates of permanent ventriculoperitoneal shunts (VPS), procedure-related complications, and 3-month functional outcomes. Patients eligible for LP had similar admission severity, and outcomes were adjusted for baseline predictors to compare strategies across centers.

Results show markedly fewer permanent VPS implantations (10% vs 68%) and lower short-term complication rates with LP, while unfavorable functional outcomes at 3 months did not differ significantly. The authors conclude LP is a viable initial option for selected patients, recommending future studies on cognitive and quality-of-life effects.

Initial Treatment: Lumbar puncture (LP) as initial treatment for acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH) resulted in significantly fewer patients requiring permanent ventriculoperitoneal shunt (VPS) implantation compared to external ventricular drainage (EVD) (10% vs 68%).

Complication Rates: LP was associated with lower short-term complication rates than EVD (21% vs 38%), including lower rates of intracerebral hemorrhage and infection, especially when LP alone was sufficient.

Functional Outcomes: No statistically significant difference was observed in unfavorable functional outcomes (Glasgow Outcome Scale 1-3 at 3 months) between LP and EVD groups, though the trend favored LP (40% vs 49%).

Patient Selection: LP is suitable as first-line treatment only for selected patients (e.g., GCS ≥7, no space-occupying hematoma, no intraventricular obstruction), while EVD remains necessary for those with contraindications to LP or requiring intracranial pressure monitoring.

Volume of CSF Drainage: Lower cerebrospinal fluid (CSF) volumes drained with LP (typically 25-30 mL per procedure) compared to EVD (hundreds of mL over days) may contribute to reduced VPS dependency.

Study Limitations: Differences in overall management strategies, patient selection, and treatment protocols between centers limit the ability to attribute outcomes solely to the initial hydrocephalus treatment modality; results should not be interpreted as definitive evidence that LP is superior to EVD.

Implications for Practice: LP can be considered as an initial treatment for acute hydrocephalus after SAH in eligible patients, but there is currently no evidence that it improves long-term functional outcomes; further research is needed to assess effects on cognition and quality of life.

Research Needs: More robust, prospective studies are required to clarify optimal patient selection, CSF drainage strategies, and comparative benefits of LP versus EVD in post-SAH hydrocephalus management.

A Multicenter Study of Noninvasive Wireless Assessment of Cerebrospinal Fluid Shunt Function in Hydrocephalus Patients

Neurosurgery 97:1397–1405, 2025

This multicenter prospective study evaluates a wearable, wireless thermal anisotropy sensor for noninvasive detection of cerebrospinal fluid (CSF) shunt flow in symptomatic hydrocephalus patients. Using a random forest algorithm on data from 112 validated subjects, the device showed high sensitivity (88.9%) and a very high negative predictive value (96.8%), though specificity was modest (49.2%) and a 37.5% no-result rate occurred.

Methods, usability, and comparative analyses are detailed: device design, algorithm development, blinded validation, and 7-day surgical follow-up with intraoperative confirmation as ground truth. Ease-of-use was rated highly, adverse events were minor skin reactions, and combined use with CT/MRI improved specificity and overall accuracy, supporting adjunctive clinical application.

Device Purpose: A novel, noninvasive, wireless wearable device was developed to assess cerebrospinal fluid (CSF) shunt flow in hydrocephalus patients presenting with possible shunt failure, using thermal anisotropy measurements to detect flow through the shunt tubing.

Study Design: The prospective, blinded, multicenter study included both pediatric and adult patients with existing ventriculoperitoneal shunts and symptoms suggestive of shunt failure; subjects underwent device evaluation alongside standard-of-care assessments.

Algorithm Performance: The device’s random forest algorithm demonstrated high sensitivity (88.9%) and negative predictive value (NPV, 96.8%) but moderate specificity (49.2%) for detecting complete shunt failure, indicating strong ability to rule out failure when flow is confirmed.

Clinical Utility: The high NPV suggests the device could help identify patients whose shunts are functioning, potentially reducing unnecessary surgical interventions or additional invasive tests.

Comparison with Standard Tests: Standard imaging tests (CT/MRI) showed moderate-to-high sensitivity and specificity but require radiation or sedation, whereas the device is noninvasive, wireless, and does not require such resources.

Combined Diagnostic Approach: When device results were combined with CT or MRI findings, specificity increased to 93.3% and NPV to 96.6%, supporting a potential workflow where the device is used to complement imaging for risk stratification.

Safety and Usability: The device was rated as easy to use by clinicians, with a low rate of mild, self-resolving skin redness and no serious adverse events reported.

Limitations: The device is not suitable as a stand-alone diagnostic tool due to moderate specificity and a substantial rate of incomplete measurements; further studies are ongoing to optimize performance and generalizability.

Update and Evaluation of a Preoperative Scoring System to Predict Long-Term Outcomes After Microvascular Decompression in Trigeminal Neuralgia

Operative Neurosurgery 29:824–831, 2025

This clinical research article evaluates and compares two preoperative scoring systems predicting long-term pain freedom after microvascular decompression (MVD) for trigeminal neuralgia (TN). Using a retrospective cohort of 410 patients with mean 63-month follow-up, the study tests the Panczykowski score (system A) and proposes a new four-variable Preoperative TN Scoring System (system B) incorporating age, TN type, neurovascular compression, and response to carbamazepine.

Results show both systems reliably stratify likelihood of pain freedom without medication, with higher scores predicting better outcomes; immediate and late complication rates are reported and limitations—including selection bias and evolving diagnostic criteria—are discussed, emphasizing need for broader external validation before widespread adoption.

Scoring Systems for Trigeminal Neuralgia (TN): Two preoperative scoring systems, the Panczykowski Score (A) and a new 4-variable Preoperative Trigeminal Neuralgia Scoring System (B), were evaluated for predicting long-term pain freedom after microvascular decompression (MVD) in TN patients.

Key Predictive Variables: Age over 45 years, classical TN type, positive response to carbamazepine, and presence/severity of neurovascular compression (NVC) significantly predict postoperative pain freedom without medication.

Scoring System A (Panczykowski): Utilizes three variables—TN type (classical/nonclassical), response to carbamazepine, and graded NVC—to assign a score from 1 to 5; higher scores correlate with greater likelihood of long-term pain freedom.

Scoring System B (Updated): Incorporates four variables—age (>45), TN type, response to carbamazepine, and NVC grade (with updated definitions)—assigning one point for each, for a total score of 0 to 4; higher scores predict increased chance of pain freedom.

Predictive Value: Both scoring systems reliably predict long-term pain freedom after MVD, with patients scoring higher on either system significantly more likely to be pain free without medication at long-term follow-up (up to 82% for highest scores).

Complication Rates: Immediate postoperative complication rate was 3.7% and late complication rate was 8.1%, with facial numbness, infection, and hearing loss among the most common complications.

Clinical Application and Limitations: These scoring systems can guide preoperative counseling and surgical candidate selection but may be limited by selection bias, changing TN diagnostic criteria, and potential oversimplification of complex patient profiles; external validation is needed before universal adoption.

Conclusion: Incorporating individual patient factors into preoperative scoring helps identify TN patients most likely to benefit from MVD, but further research and validation in broader populations are necessary for widespread clinical use.

Surgery of peritorcular meningiomas: the structural basis for preservation of torcular venous flow

J Neurosurg 143:1449–1457, 2025

This clinical and anatomical study defines the structural composition of the torcular Herophili and its implications for resection of peritorcular meningiomas, presenting histological evidence of a delaminable collagenous plane between venous endothelium and dural fibrous layers. The authors propose a four-type classification of tumor invasion based on endothelial integrity to guide operative strategy and preserve venous flow.

Clinical outcomes from 14 patients treated between 1997 and 2018 are reported, demonstrating feasibility of gross-total resection for type I–II tumors via layer-by-layer dissection with venous wall reinforcement, while types III–IV require preservation of collateral drainage and tailored reconstructive or adjunctive approaches.

• Torcular Anatomy: The torcular wall consists of two main compartments—an inner venous structure lined by endothelium and supported by elastic and smooth muscle fibers, and an outer fibrous dural layer, separated by a collagenous cleavage plane that enables surgical delamination.

• Meningioma Classification: Peritorcular meningiomas are classified into four types based on anatomical invasion: Type I (dural involvement only), Type II (dural involvement with sinus compression/displacement), Type III (endothelial layer disrupted, tumor penetrates lumen), and Type IV (complete sinus occlusion).

• Surgical Technique: For Type I and II tumors, gross-total resection is feasible by dissecting the tumor away from the inner venous wall at the cleavage plane, preserving venous integrity and flow; in Types III and IV, focus shifts to preserving venous collaterals due to disrupted or occluded flow.

• Preoperative Planning: Detailed imaging and identification of venous collaterals are critical for operative planning, especially when sinus flow is compromised or occluded.

• Outcomes: Gross-total resection was achieved in all patients with Type I and II tumors, with lower recurrence rates; subtotal resection and higher recurrence were associated with Types III and IV and higher-grade meningiomas.

• Complications and Mortality: No surgical mortality was reported; complications included wound infections and, rarely, recurrence or death related to aggressive tumor biology rather than surgery itself.

• Role of Radiotherapy: Radiation therapy was reserved for high-grade, residual, or recurrent tumors, particularly when total resection was not possible or in cases of sinus wall involvement.

• Clinical Significance: Preservation of the torcular venous wall and flow is paramount for favorable outcomes; anatomical understanding of the torcula enables safer, more effective resections and reduces recurrence in benign cases.

Masseter Sarcopenia and Mortality After Type II Odontoid Fractures in the Elderly: A 5-Year Follow-Up Study

Neurosurgery 97:1297–1307, 2025

This clinical retrospective study evaluates whether masseter sarcopenia, measured on routine head CT scans, predicts mortality after Type II odontoid fractures in elderly patients. Using masseter cross-sectional area (MCSA) thresholds, the authors found that lower MCSA is independently associated with increased 1-year mortality, while frailty indices and age drive longer-term risk.

The paper details methods, cohort characteristics (n=72, mean age 80.9), imaging measurement technique, multivariate Cox models, and Kaplan-Meier analyses. Results support MCSA as a practical prognostic marker to inform postinjury management and targeted interventions in high-risk geriatric trauma patients.

Minimally invasive surgical evacuation confers a mortality benefit in patients with moderate-sized putaminal hemorrhages

J Neurosurg 143:1514–1521, 2025

Minimally invasive surgical (MIS) evacuation of moderate-sized putaminal intracerebral hemorrhages (pICH, 10–50 mL) was retrospectively compared with matched maximal medical management in a single-center cohort. The study found similar utility-weighted functional outcomes but a marked reduction in 1-year mortality (3% surgical vs 24% medical) and shorter ICU length of stay for surgically treated patients, with an incremental cost-effectiveness ratio of ~$68,463 per QALY.

Detailed stereotactic volumetric mapping revealed that hemorrhage spatial distribution predicts outcome differently by treatment: anteromedial extension (caudate/anterior limb internal capsule) associated with worse surgical outcomes, while posterior/superior extension (corona radiata/frontal lobe) predicted worse medical outcomes. The authors propose imaging-based selection criteria for MIS candidacy and recommend validation in larger, multicenter studies.

• Mortality Benefit: Minimally invasive surgical (MIS) evacuation of moderate-sized putaminal intracerebral hemorrhages (pICHs, 10–50 mL) significantly reduced 1-year mortality compared to medical management (3% vs 24%, p = 0.010).

• Functional Outcome: Functional outcomes (utility-weighted modified Rankin Scale) were statistically similar between surgical and medical cohorts, with no significant difference detected (mean uw-mRS 0.44 vs 0.33, p = 0.174), possibly due to limited sample size.

• ICU Stay: MIS evacuation resulted in a shorter median ICU length of stay by 3 days compared to medical management (4 vs 7 days, p = 0.045).

• Cost-Effectiveness: Surgical evacuation was cost-effective with an incremental cost-effectiveness ratio of $68,462.55 per quality-adjusted life year (QALY), under the commonly accepted $100,000/QALY threshold.

• Anatomical Predictors: Poor functional outcomes after MIS were associated with anteromedial hemorrhage extension (anterior limb of internal capsule/caudate), while poor outcomes after medical management were linked to posterior/superior extension (frontal lobe/corona radiata).

• Patient Selection: Imaging-based spatial distribution of pICH can help predict which patients may benefit most from surgical versus medical management, suggesting a role for CT-based anatomical biomarkers in clinical decision-making.

• Study Limitations: Retrospective, single-center design, small sample size, and potential selection bias limit generalizability and statistical power, especially regarding functional outcome differences.

• Guideline Context: Current evidence and guidelines do not define optimal selection criteria for surgery in basal ganglia ICH, highlighting the need for further prospective, multicenter research to refine indications for MIS evacuation

Cognitive-Affective Improvement on Cerebellar Neuropsychiatric Rating Scale Scores in Adults and Children After Decompression of Chiari Malformation Type I

Neurosurgery 97:1450–1458, 2025

This clinical study assesses the Cerebellar Neuropsychiatric Rating Scale (CNRS) applied to adults and children with symptomatic Chiari Malformation Type I undergoing posterior fossa decompression. Preoperative and 8–24 month postoperative CNRS scores in 87 patients (56 follow-up) showed significant reductions in total, attentional, emotional, and autism-spectrum symptoms, with feasible administration under 15 minutes.

Correlations linked higher preoperative CNRS scores to worse neuropsychological test performance and poorer Chicago Chiari Outcome Scale subscores for attention and autism domains. Exploratory factor analysis supported five interpretable CNRS factors, suggesting CNRS as a practical perioperative patient-reported tool to capture cognitive-affective outcome domains complementary to standard functional metrics.