Magnetic resonance imaging (MRI) is routinely used to assess extent of resection after pediatric brain and spine tumor surgery and is commonly performed intraoperatively (ioMRI) or postoperatively (postopMRI). This study describes the implementation, feasibility, and workflow characteristics of end-of-surgery MRI (eosMRI), performed after wound closure but before termination of general anesthesia within a single-center pediatric neurosurgical practice and reports procedural and patient-related parameters observed over a 10-year period. We conducted a retrospective, single-center observational study including all pediatric brain and spine tumor surgeries performed with eosMRI, ioMRI, or postopMRI between July 2013 and September 2022. MRI modality selection followed institutional workflow patterns and surgeon judgment rather than predefined allocation criteria. Recorded variables included anesthesia time, surgery duration, imaging duration, patient age, tumor location, imaging-guided additional resection, and extent of resection (EOR). A total of 129 surgeries in 106 children (mean age 9 years, range 0.3–18) were analyzed: 45 eosMRI (35

BACKGROUND AND OBJECTIVES:Unruptured intracranial aneurysms (UIAs) are increasingly detected and require careful management to prevent rupture. No externally validated score currently predicts procedural risk to guide treatment decisions. We developed and validated 2 predictive scores for complications after endovascular treatment (EVT) or neurosurgical treatment (NT) of UIA using routinely collected clinical and aneurysmal features. METHODS:We conducted a multicenter retrospective study including patients with UIA treated with EVT or NT across 15 neurovascular centers (2014-2024). Predictive models were built using multivariable logistic regression, with variables derived from Delphi consensus. The primary outcome was a composite safety end point: new neurological deficits, modified Rankin Scale (mRS) worsening (≥1 point or mRS 2-5 within 30 days), or procedural death. Internal validation used bootstrapping, and external validation was performed temporally and institutionally. Model performance was assessed using area under the receiver operating characteristic curve (AUROC) and calibration. Final scores, named Morbidity and Mortality Associated Risk in the Treatment of UIAs (MARTA)-EVT and MARTA-NT, were compared with existing models identified through systematic review. RESULTS:Among 2647 patients (1907 EVT and 740 NT), procedural complications occurred in 6.3% (EVT) and 12.8% (NT). Independent predictors included age, baseline mRS, aneurysm location, size, morphology, and procedural factors. MARTA-EVT (AUROC = 0.68, 95% CI = 0.57-0.78) and MARTA-NT (AUROC = 0.65, 95% CI = 0.54-0.77) showed moderate discrimination and good calibration. MARTA-EVT outperformed existing models; MARTA-NT performed similarly to SAFETEA. Predictive models are available open-source: https://martascoreapp.shinyapps.io/martascoreapp/ . CONCLUSION:MARTA-EVT and MARTA-NT are validated tools for predicting procedural risks in UIA treatment and may support patient counseling and clinical decision making.

Objective: We evaluated whether metric 3D geometry of neurosurgical operative exposure can be recovered from standard monocular operating-microscope images combined with microscope pose data. Methods: In a phantom-based laboratory study, two aneurysm training phantoms were imaged with a ZEISS Pentero 800 microscope integrated with Brainlab Cranial Navigation. Microscope images from the standard composite video output were stored with synchronous microscope poses. After intrinsic and extrinsic calibration, depth was estimated with the pretrained Depth Anything 3 model without task-specific fine-tuning. Fused point clouds were converted to meshes using Poisson surface reconstruction. Reconstructions were compared with reference surfaces from structured-light scanning and fine-slice CT. Results: For phantom A, representing a deeper surgical corridor, reconstruction accuracy ranged from 1.95 $\pm$ 1.70 mm to 2.33 $\pm$ 2.15 mm. For phantom B, representing a directly exposed surface, accuracy ranged from 1.02 $\pm$ 0.93 mm to 1.52 $\pm$ 1.21 mm. Larger image sets mainly improved completeness, while accuracy remained within a narrower range. Corridor analysis showed preservation of overall geometry with local deviations in incompletely reconstructed regions. Conclusions: Standard monocular microscope images combined with navigation-derived pose data can reconstruct millimeter-range 3D surfaces using a foundation-model-based pipeline. These results show technical feasibility in a controlled phantom setting and support further development toward objective quantification of operative exposure, image fusion, and characterization of working spaces for future surgical instrumentation.

Background: Bilateral thalamic lesions on MRI often suggest neoplastic or inflammatory processes. However, dural arteriovenous fistulas (dAVFs) with deep venous drainage may mimic such appearances and lead to diagnostic delays or iatrogenic complications. Case summary: A 46-year-old man presented with persistent left facial and hand paresthesia after minor elbow trauma. Initial MRI demonstrated right thalamic hyperintensities, bilateral patchy enhancement, and susceptibility artifacts, raising suspicion of a tumor. Stereotactic biopsy was scheduled. Upon preoperative re-evaluation, a prominently dilated vein of Galen prompted digital subtraction angiography (DSA), revealing a Borden type III/Lawton type 1 dAVF. The fistula was successfully treated endovascularly, leading to complete neurological recovery. Conclusions: This case highlights the importance of considering vascular etiologies in bilateral thalamic lesions. Prompt vascular imaging may prevent misdiagnosis, avoid unnecessary interventions, and facilitate curative therapy.

INTRODUCTION:Spontaneous intracranial hypotension (SIH) is characterized by distinctive brain imaging findings. The Bern SIH score integrates key imaging features to aid diagnosis and standardize radiological work-up. This cross-sectional study assessed the association between symptom duration at baseline MRI and the corresponding Bern SIH score. METHODS:All consecutive SIH patients evaluated at our department between January 2013 and January 2025 were retrospectively screened. The relationship between symptom duration at baseline MRI and Bern SIH score severity was explored by categorizing data into quartiles. Ordinal logistic regression with restricted cubic splines modeled the nonlinear association between symptom duration and the Bern SIH score. Common odds ratios were estimated relative to symptom onset and plotted over the first 52 weeks. RESULTS:In total, 220 SIH patients (mean±SD age 51±14 years; 65% female) were included. The median symptom duration at baseline MRI was 5 weeks [interquartile range (IQR) 2-19] with a median Bern SIH score of 7 (IQR 4-9). Baseline Bern SIH score increased from the first quartile (median symptom duration 1.0 week; median Bern SIH score 6) to the second (4.0 weeks, SIH 8) and third quartile (8.8 weeks, SIH 7), followed by a decrease in the fourth quartile (52.3 weeks, SIH 4). Imaging features followed a similar pattern, with higher prevalence of dural enhancement, venous distention, and subdural hygromas in the second and third quartiles and lower prevalence in the fourth quartile. The severity of SIH score demonstrated a nonlinear pattern over symptom duration, with an early increase followed by gradual improvement. While adjustment for clinical factors attenuated the association and statistical significance was lost, the observed temporal trajectory remained consistent and clinically meaningful. CONCLUSION:We observed a nonlinear trajectory of the Bern SIH score, with higher baseline scores in patients presenting in the first weeks after symptom onset and lower scores over subsequent months or years. These results underscore the dynamic nature of SIH and highlight the importance of interpreting diagnostic tests within the temporal context of symptom duration and disease evolution. A low Bern SIH score in patients with long symptom duration should not exclude SIH.

Aim Achieving maximal and safe tumour resection is a key goal in brain tumour surgery. Confocal laser endomicroscopy (CLE) enables real-time visualisation of the tissue microstructure at a cellular level, potentially helping neurosurgeons distinguish non-neoplastic from neoplastic tissue. The core aim of this study was to determine the baseline diagnostic accuracy that can be achieved with CLE alone, when assessed by neuropathologists without prior CLE training and without any additional clinical or contextual information, and to compare these findings to standard haematoxylin and eosin (H & E)-based histology in a blinded setting.Methods CLE images and corresponding H & E-stained slides from 100 brain tumour patients treated at the University Hospital Bern over a 22-month period were analysed. Five blinded neuropathologists with no prior CLE experience independently evaluated the data sets.Results Based on CLE images, neuropathologists differentiated neoplastic from non-neoplastic tissue in 70.7%. The specific tumour type was correctly identified in 47.5%: gliomas in 59.8%, meningiomas in 43.8%, and metastases in 25.7%. In contrast, H & E slides were correctly classified as neoplastic in 87.6%, with 89.1% tumour-type-level accuracy (gliomas 85.6%, meningiomas 94.6%, metastases 88.2%). Confidence levels for CLE diagnoses were generally low, and no learning curve was observed.Conclusions CLE shows potential to distinguish between neoplastic and non-neoplastic tissue, but diagnostic accuracy remains lower than with H & E-stained slides. Training in CLE image interpretation is recommended to improve diagnostic accuracy. CLE imaging may have the potential to become a valuable tool for delineating brain tumour borders.

BACKGROUND/OBJECTIVE:Perimesencephalic subarachnoid haemorrhage (pmSAH) has traditionally been considered benign and of venous origin. However, advanced imaging increasingly identifies basilar artery perforator aneurysms (BAPAs) as a subset of cases historically labelled as non-aneurysmal, atraumatic (NAA) pmSAH. The objective was to compare clinical characteristics and outcomes of patients with NAA, BAPA and ruptured posterior circulation aneurysms (r-pc-AN), assessing the impact of pmSAH aetiology on patient outcomes. METHODS:This retrospective, multicentre, observational cohort study included BAPA cases from the international PERForator Aneurysm registry (2013-2025, 60 centres, 19 countries). Comparison cohorts were from a single high-volume tertiary care centre (2004-2025). The study included 444 patients (n=167 NAA, n=157 BAPA, n=120 r-pc-AN). Excellent outcome was defined as a modified Rankin Scale score of 0-1 at 3-6 months. RESULTS:Excellent outcomes were achieved in 137/167 (82%) of NAA, 96/140 (69%) of BAPA and 56/102 (55%) of r-pc-AN cohorts (p<0.001). Mortality rates were 1% (NAA), 11% (BAPA) and 18% (r-pc-AN). cCompared with BAPA, NAA patients had significantly higher odds of excellent outcome (adjusted OR, aOR 2.0, 95% CI 1.2 to 3.4, p=0.01), while r-pc-AN were associated with significantly lower odds of excellent outcome (aOR 0.5, 95% CI 0.3 to 0.9, p=0.01). Hydrocephalus and external ventricular drain rates were highest in r-pc-AN (83% and 87%), followed by BAPA (48% and 44%) and NAA (28% and 16%) (p<0.001). CONCLUSIONS:While pmSAH has been considered benign, our findings challenge this assumption. Patients with BAPA-related pmSAH demonstrated significantly worse outcomes than NAA but better outcomes than r-pc-AN. Further research is needed to distinguish BAPA-pmSAH from NAA-related pmSAH and to establish diagnostic and therapeutic guidelines. TRIAL REGISTRATION NUMBER:NCT06189014.

Importance Chronic subdural hematoma (cSDH) is among the most common neurosurgical disorders in older adults. Although short-term outcomes after surgery are favorable, long-term survival and health-related quality of life (HRQoL) remain poorly characterized. Objective To evaluate long-term survival, excess mortality, and HRQoL 10 years after surgical treatment of cSDH. Design, Setting, and Participants This population-matched cohort study was conducted at a single tertiary referral center in Switzerland, with mortality follow-up through December 31, 2023 (mean [SD] follow-up, 9.55 [1.24] years), and cross-sectional HRQoL assessment through December 31, 2024 (mean [SD] follow-up, 10.05 [1.16] years). Analyses were conducted from October to December 2025. Adults surgically treated for cSDH between June 2012 and August 2016 were included, matched with the Swiss general population by age, sex, and birth month for mortality analysis. Among survivors, those completing HRQoL assessment were compared with age- and sex-weighted European reference values. Exposure Surgically treated cSDH. Main Outcomes and Measures The primary outcome was all-cause mortality, estimated using Kaplan-Meier analysis, with excess mortality expressed as absolute survival differences and standardized mortality ratios (SMRs). Secondary outcomes were the following HRQoL domains: cognitive functioning (CF), physical functioning (PF), role functioning (RF), emotional functioning (EF), social functioning (SF), and global QoL, compared using 2-sided z tests. Results A total of 359 adults surgically treated for cSDH were included; among survivors, 147 completed HRQoL assessment and were compared with age- and sex-weighted European reference values. Among 359 patients (mean [SD] age, 73.4 [11.0] years; 117 female patients [32.6%]), overall survival was significantly lower than matched controls (hazard ratio [cohort vs control], 2.02; 95% CI, 1.73-2.37; log-rank P < .001). One-year survival in the cSDH cohort was 92.8% (95% CI, 90.1%-95.5%) vs 98.8% (95% CI, 98.7%-98.8%) in controls, representing an excess mortality of 6.0 percentage points (SMR, 3.22; 95% CI, 2.10-4.72); 5-year survival was 76.6% (95% CI, 72.3%-81.1%) vs 88.2% (95% CI, 88.2%-88.3%), representing an excess of 11.6 percentage points (SMR, 1.19; 95% CI, 0.95-1.47); and 10-year survival was 55.5% (95% CI, 50.3%-61.3%) vs 73.5% (95% CI, 73.4%-73.6%), representing an excess of 18.0 percentage points (SMR, 1.12; 95% CI, 0.94-1.31). Men reported significantly lower mean (SD) PF scores (75.9 [26.8] vs control mean score, 83.22; P < .001), RF scores (74.9 [32.0] vs 84.87; P < .001), CF scores (77.6 [22.6] vs 87.38; P < .001), and SF scores (84.3 [24.0] vs 90.00; P = .02) than controls, and women reported lower mean (SD) RF (69.0 [30.9] vs 80.91; P = .02) and CF scores (70.2 [24.8] vs 86.50; P < .001). EF and global QoL did not differ significantly from European reference values. Conclusions and Relevance In this population-matched cohort study, patients surgically treated for cSDH experienced sustained excess mortality and clinically relevant HRQoL deficits 10 years after surgery. These findings call for structured postoperative and rehabilitative care beyond the acute phase.

Background:Dexamethasone (DEX) is routinely administered perioperatively to manage tumor-associated vasogenic edema in glioblastoma (GBM), yet increasing evidence suggests that corticosteroid exposure may adversely affect survival. The magnitude of this association during the initial neurosurgical phase of care remains unclear. Methods:We performed a retrospective cohort study of patients with histologically confirmed IDH-wildtype GBM treated at a single tertiary center between 2009 and 2020. All perioperative DEX doses from admission to discharge were extracted from daily medical records. Patients were stratified based on the cumulative dose into low-dose exposure (<34 mg) and high-dose exposure (≥34 mg) groups using maximally selected rank statistics. Overall survival was analyzed using Kaplan-Meier estimates with log-rank test and multivariable Cox proportional hazards models. Adjustment variables were selected using a prespecified, causally informed framework to address confounding. Results:A total of 420 patients were included. The majority (n = 341; 81.2%) received ≥34 mg DEX perioperatively. Median OS was 13.6 months in the high-dose group and 15.0 months in the low-dose group, with significantly shorter survival observed in the high-dose cohort (log-rank P = .0103). In the adjusted Cox model, cumulative DEX ≥ 34 mg remained independently associated with increased mortality (HR: 1.40, 95% CI: 1.07-1.83; P = .013). Conclusions:Higher perioperative DEX doses were independently associated with shorter overall survival in GBM patients, emphasizing the need for judicious perioperative use with prompt tapering. Prospective studies are warranted to guide evidence-based DEX management in GBM care.

BACKGROUND:Spontaneous intracranial hypotension (SIH) is typically recognized by orthostatic headache and characteristic neuroimaging findings such as brain sagging and dural enhancement, but atypical manifestations and long-term sequelae remain underreported. OBSERVATIONS:The authors present 5 cases that illustrate uncommon SIH presentations and complications, including reversible cerebral vasoconstriction syndrome, sinus vein thrombosis, ventral spinal cord herniation, thoracic meningocele, secondary Arnold-Chiari malformation type I, and superficial siderosis. LESSONS:SIH may present with diverse complications beyond orthostatic headache; awareness and follow-up imaging are important for timely diagnosis and management. https://thejns.org/doi/10.3171/CASE26236.

Background Vertebral hemangiomas are incidental and typically, asymptomatic lesions of the spine, present in 10-12% of the population. However, aggressive vertebral hemangiomas (AVHs) can compromise the spinal canal, leading to spinal cord or nerve root compression, and require timely treatment to prevent permanent neurological deficits. Surgical management is challenging owing to the high vascularity of AVHs, and carries a significant risk of perioperative blood loss. Intraosseous ethanol injection is commonly used for sclerotization, but may not adequately deal with epidural components.Objective To carry out a staged treatment with an image-guided puncture and ethanol injection of the epidural component in 12 patients.Methods We retrospectively analyzed 12 patients with symptomatic AVHs who underwent targeted epidural ethanol injection followed by vertebral body cement augmentation, between 2017 and 2024, at three tertiary hospitals. Data collection included pre- and post-treatment imaging and clinical outcomes.Results Among 12 patients (mean age 50, women 50%), all had extensive epidural involvement and were symptomatic, including spinal cord compression and pain. Reduction in size of more than 75% of the epidural hemangioma was achieved in 8 cases, with 11 patients experiencing complete symptom resolution. Laminectomy was performed in 3 cases, while corpectomy was avoided in all cases. Two patients had neurological worsening, with one achieving complete resolution and the other having mild residual impairment after rehabilitation due to a small spinal cord ischemic lesion. No other major complications occurred.Conclusion Direct epidural ethanol injection provides a minimally invasive alternative to surgery, such as corpectomy, including rapid size reduction of the compressive epidural component, and potentially, prevents retrograde flow into arterial collaterals. Adding vertebroplasty enhances vertebral stability.

Introduction:Intradural unruptured intracranial aneurysms (UIA) can rupture and lead to subarachnoid hemorrhage. Previous studies suggest aneurysm growth being a strong risk factor for rupture. The natural history and the individual risk of growth of aneurysms remain controversial. Research question:To analyze the time to growth and identify risk factors associated with growth of UIAs. Materials and methods:Prospectively collected data of 588 patients with a total of 858 UIAs followed up by imaging were analyzed. Patients and aneurysms were categorized in a growing or a stable cohort. Logistic and survival analyses were used to assess potential factors associated with UIA growth. Results:During a median follow-up of 3.4 years (IQR 1.3 - 6.6 years), 112 (13.1%) out of the 858 UIAs showed an increase in size or a change of morphology. Posterior circulation UIAs (OR 2.01 (1.15 - 3.52), p = 0.01), aneurysm size at diagnosis (OR 1.10 (1.04 - 1.16) per mm, p = 0.002) and arterial hypertension (OR 1.60 (1.03 - 2.49), p = 0.04) were significantly associated with growth. Survival analyses confirmed a time-dependent association with growth for posterior circulation UIAs (HR 3.9 (1.74 - 8.75), p = 0.002) and aneurysm size (HR 1.22 (1.13 - 1.31), p < 0.0001). Discussion and conclusion:UIA location in the posterior circulation, a larger size at diagnosis and the presence of arterial hypertension are significant risk factors associated with UIA growth.

Introduction:Postoperative visual deficits after glioma surgery may significantly reduce quality of life. Multiple techniques for intraoperative mapping of the optic radiation (OR) have been described, but no consensus exists regarding optimal strategies, particularly for novel neurophysiological recording techniques. Research question:We conducted a scoping review to systematically organize the existing paradigms for intraoperative OR mapping, distinguishing awake task-based approaches from evoked potential recording techniques, and to outline future directions for standardization. Material and methods:This scoping review was conducted following the PRISMA-ScR guidelines. Studies describing intraoperative mapping of the OR in any surgical setting were included. Stimulation and recording parameters, as well as intraoperative task paradigms, were extracted and synthesized. Results:Nineteen studies involving 212 patients were included: four reporting neurophysiological recording techniques, 14 describing awake mapping approaches, and one combining both. Three main technique categories were identified: subcortico-cortical evoked potentials (SCEP), subcortical recorded visual evoked potentials (sVEP), and awake task-based mapping. Discussion and conclusion:A modified picture-naming task during awake mapping, presenting two figures diagonally on a screen, has proven useful in estimating the OR boundary, allowing maximal safe resection while limiting postoperative deficits to an acceptable quadrantanopia in most low-grade glioma surgeries. Alternative awake paradigms show promise but require further validation. Intraoperative neurophysiological recording techniques are technically feasible, and their role could be relevant in the future, particularly for patients unsuitable for awake surgery. However, methodological standardization and clinical validation are needed.

Background The frontal aslant tract (FAT) is associated with speech initiation, though its surgical relevance remains debated. The arcuate fasciculus (AF) is linked to phonological and semantic processing, with a well-established role for lasting outcomes. Research question To investigate the impact of isolated and combined FAT and AF disruption on transient and lasting language deficits in glioma patients. Material and methods We retrospectively analyzed 23 patients with non-contrast-enhancing IDH-mutant gliomas affecting the left FAT. Language was assessed pre-, intra-, and postoperatively. Awake speech mapping using Penfield stimulation was performed in 15 (65.2%) and neurophysiological monitoring under general anaesthesia in 8 patients. The FAT and AF were reconstructed by diffusion tensor imaging tractography, and tract integrity was classified as intact, partially disrupted, or fully disrupted. Postoperative and follow-up language deficits were correlated with the degree of tract disruption. Results FAT disruption correlated with transient deficits (τ = 0.36, p = 0.059). AF involvement was associated with transient (τ= 0.30, p = 0.088) and persistent aphasia (τ = 0.53, p = 0.033). Combined FAT and AF damage was linked to an increased deficit of both immediate (τ = 0.44, p = 0.022) and lasting (τ = 0.49, p = 0.046) language outcomes. Discussion and conclusion FAT injury contributes to transient aphasic symptoms, whereas AF disruption reflects persistent impairment. Concurrent FAT and AF involvement amplifies both short-term and lasting deficits, supporting a network-based approach to tract preservation in glioma surgery.

Introduction:Following tumor resection in non-primary motor areas, patients may suffer from paresis. To distinguish between temporary and permanent deficits, our institution uses postoperative navigated transcranial magnetic stimulation (nTMS). Research question:We investigated the association of postoperative nTMS with motor recovery. Materials and methods:We retrospectively analysed the postoperative period in a cohort of 14 patients who underwent tumor resection in the supplementary motor area (SMA), suffered a postoperative paresis and underwent a single diagnostic nTMS session. The Medical Research Council Scale (MRCS) of the upper and lower limbs was added to obtain a MRCS-sum score (0-10). Patients were divided into early nTMS (<5 days after surgery) and late nTMS (≥5 days after surgery) groups, and changes in MRCS-sum scores were compared. Results:Following the nTMS session, MRCS-sum improvement was greater in the early nTMS group (2.1 ± 1.1; n = 9) than in the pre-stimulation interval in the late nTMS group (-0.3 ± 1.9; n = 5; Mann-Whitney U, p = 0.03). Improvements around the nTMS session were also larger in the early (2.1 ± 1.1) than in the late nTMS group (0.9 ± 0.9), although this difference did not reach statistical significance (p = 0.08). Linear regression identified the pre-nTMS MRCS-sum as the strongest predictor of post-nTMS improvement (p = 0.004). Discussion and conclusion:Following surgery for tumors in the SMA, our preliminary findings suggest an association between early nTMS (<5 days after surgery) and accelerated motor recovery from temporary paresis. Prospective trials are warranted.

Introduction: Multiple intracranial aneurysms (MIAs) pose diagnostic and therapeutic challenges, and widely used rupture-risk scores have not been validated for this subgroup. Research question: To develop expert-based recommendations for the diagnosis, rupture-risk assessment, treatment selection, and follow-up of patients with MIAs. Material and methods: A modified Delphi process was conducted. After topic generation from the literature, iterative questionnaires were administered anonymously online to invited experts. Consensus was prespecified as >= 70% agreement. Twenty-six of 35 invitees (74.3%) completed the survey. Results: Consensus identified the ruptured lesion in aneurysmal subarachnoid hemorrhage (aSAH) using computed tomographic angiography (CTA) and 3D rotational digital subtraction angiography (3D-DSA). Increased rupture risk factors included aneurysm size, irregular morphology, posterior circulation location, prior hemorrhage, smoking, and family history. Individualized management was endorsed, with decision drivers such as aneurysm characteristics, patient factors, and institutional expertise. For microsurgery, a unilateral frontolateral approach was preferred; for endovascular therapy, coiling was favored for unruptured lesions. Annual imaging for untreated MIAs was recommended, but no consensus was reached on a rupture-risk scale or followup protocols. Discussion and conclusion: This consensus emphasizes the importance of accurately identifying aneurysm sources in cases of aSAH and advocates for personalized, multidisciplinary care. While single-stage treatment is recommended when safe, gaps remain, such as the lack of MIA-specific risk score validation and the best practices for post-treatment surveillance. Further multicenter research is needed to address these issues.

BACKGROUND AND PURPOSE:Localizing a CSF leak in a patient with spontaneous intracranial hypotension (SIH) is of utmost importance when pursuing a targeted therapy. The study aimed to evaluate the accuracy of dynamic myelography techniques in localizing spinal CSF leaks and report the number of examinations required, stratified by leak type and spinal level. MATERIALS AND METHODS:Consecutive patients with SIH with a spinal longitudinal extradural CSF collection (SLEC) investigated at our department from January 2013 to February 2025 were screened. All included patients underwent a dynamic myelography work-up to localize the level of spinal CSF leak using conventional dynamic myelography (CDM) and/or dynamic CT myelography (DCTM). RESULTS:In total, 198 SLEC-positive patients with SIH (mean age: 50 ± 12 years; 67% women, 133/198) were included. In total, 147 patients had a ventral (74%), 49 patients had lateral (25%), and 2 patients had a primary dorsal (1%) leak. The spinal CSF leak was localized with the first, second, third, or fourth dynamic myelography in 97 (49%), 70 (35%), 16 (8%), and 11 patients (6%), respectively. The median number of myelography examinations (CDM + DCTM) per patient to localize a CSF leak was 2 (interquartile range [IQR] 1-2; range 1-8), 1 (IQR 1-2; range 1-5) for ventral, 2 (IQR 1-2; range 1-6) for lateral, and 6 (IQR 5-7; range 4-8) for dorsal leaks. In total, 160 patients (81%) were referred for microsurgical closure. The dural leak was identified intraoperatively on the indicated vertebral level in 153 patients (96%); in 2 patients (1.3%), spontaneous sealing occurred, and in 5 patients (3%), wrong level surgery occurred. CONCLUSIONS:Dynamic myelography examinations accurately and reliably localize spinal CSF leaks in patients with SIH with SLEC. In about one-half of the patients, the level of the leak can be localized with the first CDM. In case of a repeat dynamic myelography, the technique and patient positioning can be adopted according to the results of the previous examination. Primary dorsal leaks are rare, but because of the low level of suspicion, they pose a diagnostic challenge.

BACKGROUND AND PURPOSE:Spontaneous intracranial hypotension (SIH) is caused by CSF leakage at the spinal level, resulting in craniospinal CSF depletion and often debilitating symptoms. While changes in intracranial CSF volume in SIH, particularly early depletion and normalization after treatment, are documented, reports of spinal CSF volumetry remain scarce. This study aimed to quantify intrathecal spinal CSF volume in patients with SIH before and after definitive leak closure and compare it with that in a non-SIH control cohort. MATERIALS AND METHODS:This retrospective, single-center study included 35 patients with SIH with confirmed spinal CSF leaks (types 1-3) and 10 non-SIH controls. All patients with SIH underwent surgical or endovascular leak closure and had high-quality pre- and posttreatment isotropic 3D T2-weighted MR imaging. Spinal intrathecal CSF volume was measured using semi-automated segmentation, excluding spinal longitudinal epidural fluid collections (SLEC), if present. Paired and unpaired statistical tests were applied. RESULTS:In total 18, SLEC-positive (+) and 17 SLEC-negative (-) patients and 10 non-SIH controls were evaluated. After successful leak closure, spinal CSF volume increased significantly in patients with SIH (+13%, P < .001). This increase was seen in both SLEC+ (+18%, P < .001) and SLEC- (+5%, P = .02) subgroups. No significant difference was observed between patients with SIH pretreatment and controls. However, posttreatment volumes in patients with SIH were significantly higher than those in controls (+13%, P = .04). CONCLUSIONS:Spinal CSF volumetry reliably detects a significant increase in intrathecal CSF volume following definitive leak closure in patients with SIH. Notably, posttreatment spinal CSF volumes exceeded those of non-SIH controls, suggesting a potential compensatory mechanism with overshooting CSF volume after prolonged CSF depletion.