Category: hydrocephalus

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Idiopathic normal pressure hydrocephalus: validation of the DESH score in the Capital Region of Denmark

Acta Neurochirurgica (2026) 168:155

This study validates the DESH radiological scoring system as a predictor of shunt surgery response in 127 patients with idiopathic normal pressure hydrocephalus (iNPH) at a Danish neurosurgical center, showing a significant positive association at a mean 7.4-month follow-up. The analysis adjusted for age, sex, and imaging modality, with blinded radiologic assessment and multivariate logistic regression demonstrating increased odds of a positive outcome per DESH point.

The paper also examines whether CT versus MRI confounds DESH grading, finding no evidence of modality-driven bias in this cohort but noting that formal equivalence requires paired within-patient imaging. Limitations include selection bias from preselected tested patients and lack of paired imaging, while strengths are external validation, cohort size, and blinded scoring.

Objective External validation of the DESH score as a prognostic marker for shunt response in idiopathic normal pressure hydrocephalus (iNPH), and assessment of whether CT vs MRI confounds DESH grading/outcome association.

Cohort Retrospective study of 127 shunt-operated iNPH patients (2013–2020) with preoperative CT and/or MRI and ≥2 months follow-up; mean follow-up 7.4 months.

Predictors assessed Radiologic markers (Evans’ index, callosal angle, Sylvian fissure dilation, tight high convexity, focal sulci) and their combined DESH score were compared against shunt response.

Primary finding Higher DESH score was significantly associated with objective shunt response after adjustment for age, sex, and modality (OR 1.35, p=0.036).

Modality impact No significant difference in DESH score assessments between CT and MRI, and including/excluding modality did not meaningfully change regression coefficients.

Outcome rate 81.9% of patients had a positive response to shunt surgery in this cohort.

Interpretation CT may be a practical alternative for DESH-based initial evaluation when MRI is impractical, but formal equivalence of CT vs MRI DESH scoring requires paired-imaging studies.

Key limitation Cohort was preselected based on prior diagnostic testing (e.g., infusion/tap testing), increasing pretest probability and limiting generalizability (potential selection bias).

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Predictive Values of Lumbar Infusion Testing in Idiopathic Normal Pressure Hydrocephalus Diagnosis

Neurosurgery 99:50–59, 2026

This study evaluates lumbar infusion testing (LIT) as an adjunctive diagnostic tool for idiopathic normal-pressure hydrocephalus (iNPH) in a cohort of 165 patients, defining an optimal Rout threshold (≈12 mm Hg·mL−1·min−1) with good sensitivity and specificity. It reports LIT’s role in multidisciplinary decision-making, its safety, and its contribution to selecting patients for ventriculoperitoneal shunting and improving postshunt outcomes.

The authors detail standardized clinical, radiological, and hydrodynamic assessments, show outcome rates after shunting across pretest probability groups, and propose a diagnostic algorithm positioning LIT as a reproducible, low-morbidity adjunct when clinical and imaging data remain inconclusive.

Goal Evaluate lumbar infusion testing (LIT) performance to support shunt decision-making in suspected idiopathic normal-pressure hydrocephalus (iNPH), given no single reliable diagnostic test exists.

Cohort 201 referred; 165 had interpretable LIT results (mean age 79), assessed with combined clinical, radiological, and hydrodynamic workup.

Symptom profile In the 165-patient LIT cohort, gait disturbance was present in 98.8%, cognitive impairment in 86.6%, and urinary disturbances in 58.8%.

Key metric CSF outflow resistance (Rout) differed significantly across diagnostic probability groups, and the optimal cutoff was ~12 mm Hg/mL/min (AUC 0.8441), yielding 78.1% sensitivity and 74.3% specificity for shunt-response prediction.

Clinical utility (borderline cases) In patients initially classified as possible iNPH who were shunted based on LIT findings, 75.6% improved clinically.

Outcomes (high-probability cases) In the probable iNPH group, 87.1% of shunted patients showed improvement.

Safety No complications (e.g., intracranial hypotension syndrome or infection) were observed after LIT in this cohort.

Conclusion LIT is not definitive for iNPH diagnosis but is a safe, reproducible adjunct that helps in diagnostic uncertainty, supports earlier decision-making, and can help avoid unnecessary surgery when combined with clinical and radiological assessment.

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The Lumboperitoneal Shunt Study: A Systematic Review and Single-Arm Meta-Analysis of 2696 Patients

Neurosurgery 99:3–18, 2026

Scope Systematic review + single-arm random-effects meta-analysis of 49 studies including 2696 patients who underwent lumboperitoneal shunt (LPS) placement.

Search/eligibility Databases: PubMed, Embase, Web of Science (through Sept 2023); included observational studies reporting LPS complications; excluded case reports (≤4 patients), non-English, overlapping cohorts, prior non-LPS shunts; study was not prospectively registered.

Main etiologies Largest indication groups were communicating hydrocephalus (693), normal pressure hydrocephalus (631), and idiopathic intracranial hypertension (275) (1599 combined).

Revision risk Overall pooled risk of requiring shunt revision: 25% (95% CI 18%–32%; I²=93%) at median mean follow-up 19.2 months; by etiology: CH 21%, IIH 46%, NPH 10%.

Complication risks Infection: 1% (95% CI 1%–2%; I²=25%); shunt-related mortality: 0.1% (3 deaths).

Overdrainage/tonsillar herniation Overdrainage occurred in 119 patients with high heterogeneity (I²=75%); tonsillar herniation in 19 patients with significant heterogeneity (I²=50%), both reported as minimal pooled risk.

Revision causes Most common reasons for revision were obstruction (30%) and migration/slippage/fracture (20%).

Overall conclusion LPS shows acceptable revision and complication rates and appears comparable to ventriculoperitoneal shunts (VPS), but substantial heterogeneity limits confidence; supports broader integration of LPS in Western practice and calls for randomized trials.

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Diagnosing Cerebrospinal Fluid Shunt Failure: Systematic Review and Meta-Analysis of Noninvasive and Minimally Invasive Tests in Children and Adults

Neurosurgery 98:1206–1220, 2026

This systematic review and meta-analysis evaluates diagnostic performance of noninvasive and minimally invasive tests (X-ray shunt series, CT, MRI, nuclear scintigraphy, thermal flow) for cerebrospinal fluid shunt failure in pediatric and adult patients, synthesizing 33 studies and 8,077 patients. Pooled accuracy was 82%, sensitivity 67%, and specificity 88%, with X-ray series showing lower sensitivity but higher specificity compared with CT.

The analysis highlights substantial study bias—especially in patient selection and reference standards—and concludes no existing test is adequate as a standalone diagnostic for shunt failure, underscoring the need to optimize diagnostic pathways, reduce harm, and develop improved point-of-care functional tests.

Objective Assess diagnostic performance of noninvasive/minimally invasive tests (X-ray shunt series, CT, MRI, nuclear scintigraphy, thermal flow evaluation) for suspected CSF shunt failure in pediatric and adult patients.

Methods Systematic review/meta-analysis (PROSPERO CRD42024596142) including patients with permanent CSF shunts who underwent the above index tests; performance (accuracy, sensitivity, specificity) modeled via meta-regression incorporating test type, age group, follow-up timeframe, and shunt type.

Evidence base PubMed search (Oct 22, 2024) screened 465 articles; 33 studies included, totaling 8077 patients.

Pooled performance Overall pooled accuracy 82%, sensitivity 67%, specificity 88% across included tests.

Key comparative finding (sensitivity) X-ray shunt series had significantly lower sensitivity than CT (OR 0.106, 95% CI 0.056–0.201; overall effect of test type on sensitivity P = .013).

Key comparative finding (specificity) No overall effect of test type on specificity (P = .192), but X-ray shunt series showed higher specificity than CT in subgroup analysis (OR 4.04, 95% CI 1.938–8.424).

Covariates No significant effects of age group, follow-up timeframe, or shunt type on accuracy, sensitivity, or specificity.

Conclusion/limitations No test performed well enough to serve as a standalone diagnostic for shunt failure; evidence limited by high risk of bias, especially in the reference standard domain for most studies.

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Predictors of shunt responsiveness and outcomes in idiopathic normal pressure hydrocephalus: a retrospective cohort study

Acta Neurochirurgica (2026) 168:80

This retrospective cohort study from Tel-Aviv Medical Center evaluates predictors of clinical improvement after shunt placement in patients with idiopathic normal pressure hydrocephalus (iNPH) assessed between 2020–2022. The authors analyze clinical presentation, standardized gait testing, MRI features (including DESH), CSF biomarkers (notably total tau and protein), and PET findings to determine associations with lumbar puncture (LP) responsiveness and one-year post-shunt outcomes.

Key findings show 37% LP responsiveness among 167 patients, 38 underwent shunting, and 55% of shunted patients had favorable one‑year outcomes. Lower CSF total tau and presence of a DESH imaging pattern correlated with LP response and improved one‑year outcomes, while greater immediate post‑LP gait improvement predicted sustained benefit; vascular comorbidities and standard MRI metrics were less predictive.

Objective Identify clinical, imaging, and CSF biomarkers linked to favorable outcomes after shunt placement in suspected idiopathic normal pressure hydrocephalus (iNPH).

Cohort & pathway 183 patients were evaluated (2020–2022); 167 underwent high-volume lumbar puncture (≥30 mL removed); LP responders were referred for shunting and followed for 1 year.

LP responsiveness rate 62/167 (37%) improved after CSF drainage and were referred for shunt surgery; 38/62 (61%) ultimately underwent shunt placement.

Clinical pattern Gait disturbance was the most common presenting symptom (68%) and was more frequent in LP responders, while cognitive symptoms were more common among non-responders (29.5% vs 10%).

CSF biomarkers (LP response) LP responders had lower CSF total tau (t-tau) and protein than non-responders.

Imaging marker (LP response) The DESH pattern was more common in LP responders (73% vs 46%).

Shunt outcomes (1 year) 21/38 (55%) shunted patients had a favorable outcome at one year; favorable outcome was associated with more frequent DESH and lower t-tau (trend).

Overall takeaway Combining post-LP clinical response with DESH imaging and CSF t-tau may help refine selection for shunting and predict better outcomes.

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Predictors of shunt responsiveness and outcomes in idiopathic normal pressure hydrocephalus: a retrospective cohort study

Acta Neurochirurgica (2026) 168:80

This retrospective cohort study from Tel-Aviv Medical Center evaluates predictors of clinical benefit following shunt placement in idiopathic normal pressure hydrocephalus (iNPH). Among 167 patients undergoing high-volume lumbar puncture, 62 (37%) were LP responders and 38 proceeded to shunting; 21 of 38 (55%) experienced favorable outcomes at one year, with gait disturbance the commonest presenting symptom.

Key associations with LP responsiveness and positive one‑year shunt outcome included lower CSF total tau, lower CSF protein, younger age at symptom onset, pronounced immediate gait improvement after CSF drainage, and the presence of a disproportionately enlarged subarachnoid-space hydrocephalus (DESH) imaging pattern. The authors recommend a multimodal approach combining clinical response, imaging, and fluid biomarkers to refine patient selection for shunting.

Aim Identify clinical, imaging, and CSF biomarkers linked to LP responsiveness and 1-year shunt outcomes in suspected idiopathic normal pressure hydrocephalus (iNPH).

Cohort & pathway 183 evaluated (2020–2022); 167 underwent high-volume LP (≥30 mL removed); LP responders were referred for shunting and outcomes assessed at 1 year.

LP response rate 62/167 (37%) improved after CSF drainage and were referred; 38/62 (61%) ultimately received a shunt (others mainly declined surgery).

Clinical predictors (LP response) Gait disturbance was the most common initial symptom (68%) and was more frequent in LP responders, while cognitive symptoms were more common as the first symptom among non-responders.

CSF biomarkers (LP response) LP responders had lower CSF total tau (t-tau) and protein than non-responders.

Imaging predictor (LP response) DESH pattern was more common in LP responders (73% vs 46%).

Shunt effectiveness Among shunted patients, 21/38 (55%) had a favorable clinical outcome at 1 year.

Outcome predictors (post-shunt) Favorable 1-year outcomes were associated with more frequent DESH and a trend toward lower t-tau.

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External Ventricular Drain Placement Using Active Augmented Reality Guidance

Operative Neurosurgery 30:414–421, 2026

This technical note presents a proof-of-concept augmented reality (AR) system that guides external ventricular drain (EVD) placement by integrating cloud-based automatic CT segmentation, PACS compatibility, trajectory planning, point-based image-to-patient registration, and real-time 3D AR guidance via an AR head-mounted display. The low-cost, end-to-end workflow and universal tracking tools aim to reduce attention shifts and improve accessibility compared with conventional neuronavigation.

The system was tested in a phantom study with 29 AR-guided EVD insertions by neurosurgical clinicians, yielding 69% optimal placements (Kakarla grade 1), a mean distance-to-target of 9.49 mm, mean angular deviation of 9.20°, an FRE of 4.00 mm, and mean procedural time of 22:45. Authors identify human–computer interaction, tracking fidelity, registration accuracy, and procedural time as primary areas for refinement before clinical adoption.

Augmented Reality (AR) Guidance: A low-cost, end-to-end AR system was developed for external ventricular drain (EVD) placement, integrating real-time 3D guidance, automated CT segmentation, and compatibility with standard hospital PACS infrastructure, all visualized through AR head-mounted displays (AR-HMDs).

Workflow Components: The system includes cloud-based image storage, automatic segmentation, trajectory planning, point-based image-to-patient registration, and real-time EVD tracking, aiming to reduce attention shifts and improve procedural integration.

Proof-of-Concept Results: In simulated procedures on anatomical phantoms with small ventricles, 69% of placements were optimal (Kakarla 1), with a mean distance to target of 9.49 mm and mean angular deviation of 9.20°, but accuracy is not yet at the level of best clinical standards.

Procedural Time: The mean workflow duration was nearly 23 minutes, which is longer than acceptable for emergency EVD placements, with most of the added time attributed to trajectory planning, marker attachment, and image-to-patient registration.

Usability and Interface Challenges: Users experienced difficulties with human-computer interaction, including issues with holographic controls, visual clutter, and marker tracking, which impacted both speed and accuracy.

Affordability and Accessibility: The AR-HMD system (approx. $4950) is significantly less expensive than traditional neuronavigation systems, potentially increasing access to advanced guidance in resource-limited settings

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

Acta Neurochirurgica (2026) 168:29

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

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

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

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

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

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

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

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

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

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

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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.

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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.

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

J Neurosurg 143:1254–1261, 2025

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

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

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

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

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

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

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

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

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

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

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The diagnostic value of the lumbar infusion test to predict symptomatic improvement after shunting for normal pressure hydrocephalus. A meta‑analysis

Acta Neurochirurgica (2025) 167:180

This meta-analysis found that the lumbar infusion test (LIT) has poor negative predictive value for predicting non-response to shunting in normal pressure hydrocephalus. LIT cannot reliably exclude patients from shunt surgery and should not be used for this purpose in its current form.

• The lumbar infusion test (LIT) is used to predict which normal pressure hydrocephalus (NPH) patients will benefit from CSF shunting.

• This meta-analysis pooled sensitivity, specificity, and negative predictive value (NPV) of LIT from 10 studies.

• Sensitivity of LIT (using Rout) was moderate (77–82%) at lower cutoffs (12–14 mmHg/ml/min), but specificity was low (34–37%).

• Higher Rout cutoff (18 mmHg/ml/min) increased specificity (78%) but decreased sensitivity (37%).

• NPV was consistently low for all cutoffs (≤33%), meaning LIT is poor at ruling out shunt responders.

• No other LIT parameters (e.g., plateau pressure, CSF amplitude) showed better diagnostic value.

• The test cannot be used to exclude patients from shunt implantation due to high false negative rates.

• Future research should focus on improving the negative predictive value of LIT for NPH.

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Prediction of Shunt Malfunction Using Automated Ventricular Volume Analysis and Radiomics

Neurosurgery 97:242–249, 2025

Automated ventricular volume analysis using convolutional neural networks and radiomics, combined with clinical features, improves accuracy in diagnosing hydrocephalus and shunt malfunction from CT scans, outperforming traditional 2D methods and enabling earlier, more reliable detection without requiring prior imaging.

• Automated ventricular volume analysis and radiomics were used to predict shunt malfunction and diagnose hydrocephalus from CT scans.

• Traditional 2D measurements are less sensitive than 3D volumetric analysis for detecting ventricular changes.

• A convolutional neural network (CNN) segmented ventricles, and volumes were compared to age- and sex-matched normative data.

• Volumetric analysis alone achieved up to 73% accuracy (AUC 0.772) for detecting pathology; combining radiomics and clinical data improved accuracy significantly.

• The best model (support vector machine) using selected radiomics features and clinical data reached an AUC of 0.92–0.93 and F1-score of 0.848.

• Automated segmentation is time-efficient, reduces observer variability, and may improve early and accurate diagnosis.

• Limitations include single-institution data, scanner variability, and need for external validation.

• Future work should expand datasets and improve model generalizability, including to MRI and other manufacturers.

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Comprehensive Morphometric Analysis to Identify Key Neuroimaging Biomarkers for the Diagnosis of Adult Hydrocephalus Using Artificial Intelligence

Neurosurgery 96:1386–1396, 2025

This study used AI and SHAP analysis to identify five key, easily measurable 1-D neuroimaging biomarkers—FTHR, MEI, MCMI, SMLH, and CPCA—for accurately diagnosing adult non-normal pressure hydrocephalus, offering a practical, standardized, and interpretable approach to improve early detection and clinical decision-making.

• Hydrocephalus diagnosis is often inconsistent due to reliance on clinical and qualitative radiological assessments.

• This study used artificial intelligence (AI) and SHAP analysis to identify key, easily measurable neuroimaging biomarkers for adult non-normal pressure hydrocephalus (non-NPH).

• A comprehensive set of 21 morphometric features was analyzed from MRI images of 42 adult non-NPH patients and 40 healthy controls.

• Gradient Boosting was the best-performing AI classifier, achieving 0.94 accuracy and 0.97 AUC.

• Ventricular volume is the most important biomarker, but measurement is complex for clinicians.

• Five key 1-D biomarkers identified are: frontal-temporal horn ratio (FTHR), modified Evans index (MEI), modified cella media index (MCMI), sagittal maximum lateral ventricle height (SMLH), and coronal posterior callosal angle (CPCA).

• These five markers are easily measurable and provide high diagnostic accuracy, supporting practical clinical use.

• The approach addresses multicollinearity and improves diagnostic standardization, but further validation with larger datasets is needed.

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Programmable gravitational valves in idiopathic normal pressure hydrocephalus: long‑term outcomes after a 3‑year follow‑up

Acta Neurochirurgica (2025) 167:151

This study evaluates the long-term outcomes of using programmable gravitational valves in treating idiopathic normal pressure hydrocephalus (iNPH). Results indicate significant clinical improvement, low complication rates, and no valve dysfunction, suggesting these valves are a safe and effective alternative to traditional fixed-pressure valves.

• The study evaluates the safety and effectiveness of adjustable gravitational valves (GVs) for treating idiopathic normal pressure hydrocephalus (iNPH) over a 3-year follow-up period.

• 76 patients were treated with ventriculoperitoneal shunts using programmable GVs, showing significant clinical improvement.

• The study found that 71.1% of patients required valve setting adjustments post-implantation, mainly for the differential pressure unit (DPU).

• No cases of valve dysfunction were reported, contrasting with previous literature findings.

• Postoperative complications were acceptable, with a low rate of overdrainage-related issues due to the use of GVs.

• The study suggests that GVs offer a higher therapeutic index than fixed differential pressure valves, despite higher costs.

• The addition of gravitational units to the shunt system significantly reduces overdrainage complications.

• The study calls for further investigation to confirm results and assess the cost-effectiveness of GVs in treating iNPH.

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Cognitive improvement after endoscopic third ventriculostomy surgery in long-standing overt ventriculomegaly in adults

J Neurosurg 142:875–883, 2025

Endoscopic third ventriculostomy (ETV) significantly improves long-term memory and visuospatial skills in patients with long-standing overt ventriculomegaly in adults (LOVA), especially those with higher premorbid IQ. The study highlights the role of cognitive reserve in facilitating cognitive recovery post-surgery.

• Endoscopic third ventriculostomy (ETV) surgery leads to cognitive improvement in patients with long-standing overt ventriculomegaly in adults (LOVA), particularly in long-term memory and visuospatial skills.

• Cognitive reserve (CR) plays a crucial role in predicting cognitive recovery post-surgery, with higher premorbid IQ linked to better outcomes.

• LOVA is a chronic form of hydrocephalus that becomes symptomatic in adulthood, often characterized by cognitive deficits and gait disturbances.

• ETV is favored over ventriculoperitoneal shunt (VPS) due to lower complication rates, making it the preferred treatment option.

• Preoperative cognitive profiles of LOVA patients show deficits primarily in long-term memory and visuospatial skills, while other cognitive domains remain unaffected.

• Postoperative improvements are significant and sustained over time, with the majority of patients reporting enhanced cognitive function and quality of life.

• Symptom duration does not hinder the efficacy of ETV, and longer symptom history may lead to better outcomes in visuospatial skills.

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When and how are complications suspected after shunt surgery in patients with normal pressure hydrocephalus?

Acta Neurochirurgica (2025) 167:6

The follow-up routine for patients with idiopathic normal pressure hydrocephalus (iNPH) after shunt surgery differs across medical centers. Shunt surgery is not without risks, with complications emerging at various times after the procedure. The aim was to explore the timing and methods of detecting complications following ventriculoperitoneal shunt surgery for iNPH.

Methods This retrospective study examined patients who underwent shunt surgery for iNPH at Uppsala University Hospital between 2011 and 2018. The cohort comprised 491 patients. Postoperative complications within the first 12 months were recorded from medical records. Complications were classified by type, and the method or event that first indicated the complication was documented.

Results Of the 491 patients, 102 (20.8%) experienced complications during the one-year follow-up period, with a shunt revision rate of 15.5% (76 patients requiring reoperation). Subdural hematomas/hygromas were the most common complications, with 27 cases; only three required surgical intervention. Most complications were identified through additional appointments triggered by patient-reported symptoms (31.4%), while the planned follow-up routine with CT scans and planned follow-up visits together accounted for 56% of the detections. The 3-month and 12-month follow-up visits detected similar proportions of complications (12.7% and 11.8%, respectively).

Conclusion The majority of the complications were detected at a planned visit or investigation. Given the cognitive impairments in iNPH patients and that signs of shunt dysfunction can be subtle, a structured follow-up routine is important for timely detection of complications. The findings suggest that both CT scans and planned follow-up visits are critical components of effective postoperative monitoring.

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Artificial Intelligence for Automatic Analysis of Shunt Treatment in Presurgery and Postsurgery Computed Tomography Brain Scans of Patients With Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 95:1329–1337, 2024

Ventriculo-peritoneal shunt procedures can improve idiopathic normal pressure hydrocephalus (iNPH) symptoms. However, there are no automated methods that quantify the presurgery and postsurgery changes in the ventricular volume for computed tomography scans. Hence, the main goal of this research was to quantify longitudinal changes in the ventricular volume and its correlation with clinical improvement in iNPH symptoms. Furthermore, our objective was to develop an end-to-end graphical interface where surgeons can directly drag-drop a brain scan for quantified analysis.

METHODS: A total of 15 patients with 47 longitudinal computed tomography scans were taken before and after shunt surgery. Postoperative scans were collected between 1 and 45 months. We use a UNet-based model to develop a fully automated metric. Center slices of the scan that are most representative (80%) of the ventricular volume of the brain are used. Clinical symptoms of gait, balance, cognition, and bladder continence are studied with respect to the proposed metric.

RESULTS: Fifteen patients with iNPH demonstrate a decrease in ventricular volume (as shown by our metric) postsurgery and a concurrent clinical improvement in their iNPH symptomatology. The decrease in postoperative central ventricular volume varied between 6 cc and 33 cc (mean: 20, SD: 9) among patients who experienced improvements in gait, bladder continence, and cognition. Two patients who showed improvement in only one or two of these symptoms had <4 cc of cerebrospinal fluid drained. Our artificial intelligence–based metric and the graphical user interface facilitate this quantified analysis.

CONCLUSION: Proposed metric quantifies changes in ventricular volume before and after shunt surgery for patients with iNPH, serving as an automated and effective radiographic marker for a functioning shunt in a patient with iNPH.

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Antibiotic-Impregnated Ventriculoperitoneal Shunts Decrease Bacterial Shunt Infection: A Systematic Review and Meta-Analysis

Neurosurgery 95:1263–1273, 2024

Antibiotic-impregnated shunts seem to be beneficial in preventing bacterial infections and decreasing mortality by effectively inhibiting microbial growth in the shunt system and reducing the risk of shunt-associated infections. This study aimed to evaluate the efficacy of antibiotic-impregnated shunt catheters (AISC) in reducing the incidence of bacterial shunt infection in patients with hydrocephalus.

METHODS: The protocol was registered on PROSPERO. A meta-analysis was conducted by searching 3 databases (PubMed, Scopus, CENTRAL) for relevant randomized controlled trials and observational studies. We included all studies published until November 2022 in any language. The primary outcome was the rate of bacterial infections, whereas the rate of shunt failure was our secondary endpoint. Odds ratios (OR) with 95% CI were calculated using a random-effects model.

RESULTS: A total of 27 articles with 27 266 shunt operations were included in this study. The results indicated that using AISC is significantly associated with reduction in infections (OR = 0.42; 95% CI: 0.33-0.54). Regarding shunt failure, there was a tendency in favor of AISC use (OR = 0.73; 95% CI: 0.51-1.06).

CONCLUSION: Our study provided evidence that AISC is significantly associated with the reduction in the rate of bacterial ventriculoperitoneal-shunt infection. In addition, there was a tendency toward AISC to decrease shunt failure compared with the standard shunt.

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Effect of cranial entry site on the rate of proximal catheter misplacement in ventriculoperitoneal shunt insertion

J Neurosurg 141:1418–1426, 2024

The insertion of a ventriculoperitoneal shunt (VPS) is a common neurosurgical procedure, but the optimal entry site of the ventricular catheter is still under debate. In this study, the authors compare the parietal (Keen’s) and frontal (Kocher’s) entry sites in terms of the rate of revision surgery due to ventricular catheter misplacement, VPS dysfunction, and VPS infection.

METHODS The authors retrospectively analyzed the data on consecutive adults (age ≥ 18 years) who had undergone primary VPS insertion between 2010 and 2020 at two neurosurgical centers. One center regularly inserts the ventricular catheter frontally (frontal group); the other center, parietally (parietal group). The primary outcome of interest was the rate of ventricular catheter misplacement necessitating revision surgery. Secondary outcomes were functional outcome as measured by the modified Rankin Scale (mRS), rate of revision surgery for VPS dysfunction and infection, as well as early (≤ 30 days) and late (> 30 days) mortality rates. Propensity score matching was performed based on baseline variables, such as normal pressure hydrocephalus, postinfectious hydrocephalus, and idiopathic intracranial hypertension, which were identified as predictors of ventricular catheter misplacement using logistic regression analysis.

RESULTS Among 539 consecutive patients, 301 (55.8%) were in the frontal group and 238 (44.2%) in the parietal group. Postoperative rates of revision surgery due to misplacement were comparable in the two catheter entry site groups (frontal 14 [4.7%] vs parietal 11 [4.6%], p = 0.987). Rates of revision surgery for VPS dysfunction (14 [4.7%] vs 10 [4.2%], respectively, p = 0.802) and infection (22 [7.3%] vs 10 [4.2%], p = 0.13) exhibited no significant differences. Favorable functional outcomes (mRS score ≤ 2; 164 [76.3%] vs 174 [79.5%], respectively, p = 0.058) and early mortality rates (5 [1.7%] vs 6 [2.5%], p = 0.483) were similar between the groups. After propensity score matching, the primary and secondary outcome measures remained comparable between the groups.

CONCLUSIONS The entry site of the ventricular catheter in VPS surgery does not seem to affect proximal revision rates. Further, revision rates due to VPS dysfunction, VPS infection, and morbidity were comparable as well.

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