Treatment of Brain Arteriovenous Malformations.

Brain arteriovenous malformations (AVMs) are a rare entity of vascular anomalies, characteristic of anatomical shunting where arterial blood directly flows into the venous circulation. The main aim of the active treatment policy of brain AVMs is the prevention of haemorrhage. There are well-established treatment strategies that continually improve in their safety and efficacy, primarily due to the advances in imaging modalities, targeted and novel techniques, the development of alternative treatment approaches, and even better experience with the disease itself. There are interesting imaging novelties that may be prospectively applicable in the decision-making and planning of the most effective treatment approach for individual patients with intracranial AVM. Surgery is often considered the first-line treatment; however, each patient should be evaluated individually, and the risks of the active treatment policy should not overcome the benefits of the spontaneous natural history of the disease. All treatment modalities, i.e., surgery, radiosurgery, endovascular embolization, and observation, are justified but need to be meticulously selected for each individual patient in order to deliver the best treatment outcome. This chapter deals with historical and currently applied dogmas, followed by introductions of advances in each available treatment modality of AVM management.

Comparison of decline in different cognitive domain in patients with normal pressure hydrocephalus.

We sought to describe the cognitive profile of patients with Idiopathic Normal Pressure Hydrocephalus (iNPH) using a comprehensive neuropsychological battery. Based on age and education correlated norms, we aimed to compare performance in each measured cognitive domain: executive functions (EFs), verbal memory (VM), non-verbal memory (nVM), visuoconstructional abilities (VA) and attention/psychomotor speed (A/PS). Patients diagnosed with iNPH underwent comprehensive neuropsychological evaluation before shunting. Their performance was compared to the age and education correlated norms. Correlation of different cognitive domains in iNPH profile was performed. A total of 53 iNPH patients (73.21 ± 5.48 years) were included in the study. All of the measured cognitive domains were significantly damaged. The most affected domains were EFs and VM (p<0.001 and p<0.001, respectively). A/PS domain was affected milder than EFs and VM (p<0.001). The least affected domains were nVM (p<0.001) and VA (p<0.001). Patients with iNPH are affected in all cognitive domains and the cognitive decline is uneven across these domains. The impairment of memory was shown to depend on the presented material. VM was shown to be much more severely affected than nVM and along with VM, EFs were shown to be the most affected. A/PS speed was shown to be less affected than VM and EFs and the least affected domains were nVM and VA.

Diffusion tensor imaging helps identify shunt-responsive normal pressure hydrocephalus patients among probable iNPH cohort.

The aim of this study was to investigate whether white matter changes as measured by diffusion tensor imaging (DTI) can help differentiate shunt-responsive idiopathic normal pressure hydrocephalus (iNPH) patients from patients with other causes of gait disturbances and/or cognitive decline with ventriculomegaly whose clinical symptoms do not improve significantly after cerebrospinal fluid derivation (non-iNPH). Between 2017 and 2022, 85 patients with probable iNPH underwent prospective preoperative magnetic resonance imaging (MRI) and comprehensive clinical workup. Patients with clinical symptoms of iNPH, positive result on lumbar infusion test, and gait improvement after 120-h lumbar drainage were diagnosed with iNPH and underwent shunt-placement surgery. Fractional anisotropy (FA) and mean diffusivity (MD) values for individual regions of interest were extracted from preoperative MRI, using the TBSS pipeline of FSL toolkit. These FA and MD values were then compared to results of clinical workup and established diagnosis of iNPH. An identical MRI protocol was performed on 13 age- and sex-matched healthy volunteers. Statistically significant differences in FA values of several white matter structures were found not only between iNPH patients and healthy controls but also between iNPH and non-iNPH patients. ROI that showed best diagnostic ability when differentiating iNPH among probable iNPH cohort was uncinate fasciculus, with AUC of 0.74 (p < 0.001). DTI methods of white matter analysis using standardised methods of ROI extraction can help in differentiation of iNPH patients not only from healthy patients but also from patients with other causes of gait disturbances with cognitive decline and ventriculomegaly.

Congenital internal carotid artery hypoplasia: A systematic review.

This review evaluates the current evidence for the clinical management of congenital internal carotid artery hypoplasia (CICAH). We summarise clinical presentations diagnostic standards, imaging recommendations, treatment and follow-up. The review was prompted by a case of CICAH in a 50-year-old female who presented to our neurosurgery clinic with an acute episode of vertigo. The patient underwent CT angiogram, which showed an unusually low right carotid bifurcation. The right internal carotid artery (ICA) was hypoplastic, and the A1 segment of the anterior cerebral artery (ACA) was absent. Skull base CT showed an ipsilateral hypoplastic carotid canal. To summarise current evidence for clinical management of CICAH we followed PRISMA guidelines to identify papers meeting our predefined inclusion criteria. We searched three databases using the terms 'ICA' and 'Hypoplasia'. We reviewed 41 papers meeting our criteria. 34 were clinical reports. We performed a data extraction and quality appraisal on these reports. We found that CICAH may be less rare than previously described. Blood pressure control in CICAH is crucial due to the increased risk of stroke and aneurysm formation. Follow-up imaging is strongly recommended. Carotid doppler sonography is a powerful and underutilised diagnostic tool, and carotid canal hypoplasia is not a pathognomic sign. In conclusion, clinicians should be alert to anatomic variations such as CICAH because these produce haemodynamic changes that may have serious clinical consequences. We recommend a central registry of patients with CICAH in order to understand the longer-term natural history of the condition.

Partial medial clinoidectomy with optic canal roof drilling for clipping of ophthalmic artery aneurysms: how I do it.

BACKGROUND: Clipping of ophthalmic artery (OA) aneurysms present one of the treatment strategies for long-term disease management. Existing surgical techniques primarily require extra/intradural removal of the anterior clinoid process, carrying a higher risk of infection, damage to surrounding structures or technical complications. METHODS: We present the technique of minimally invasive partial medial clinoidectomy with the unroofing of the optic canal for surgical clipping of OA aneurysms, and besides its pros and cons, we also discuss proper technical indications. CONCLUSION: The partial medial clinoidectomy improves manoeuvrability around the paraclinoid region, provides better protection for adjacent structures and renders excellent treatment outcome.

Boosting phase-contrast MRI performance in idiopathic normal pressure hydrocephalus diagnostics by means of machine learning approach.

OBJECTIVE: Phase-contrast MRI allows detailed measurements of various parameters of CSF motion. This examination is technically demanding and machine dependent. The literature on this topic is ambiguous. Machine learning (ML) approaches have already been successfully utilized in medical research, but none have yet been applied to enhance the results of CSF flowmetry. The aim of this study was to evaluate the possible contribution of ML algorithms in enhancing the utilization and results of MRI flowmetry in idiopathic normal pressure hydrocephalus (iNPH) diagnostics. METHODS: The study cohort consisted of 30 iNPH patients and 15 healthy controls examined on one MRI machine. All major phase-contrast parameters were inspected: peak positive, peak negative, and average velocities; peak amplitude; positive, negative, and average flow rates; and aqueductal area. The authors applied ML algorithms to 85 complex features calculated from a phase-contrast study. RESULTS: The most distinctive parameters with p < 0.005 were the peak negative velocity, peak amplitude, and negative flow. From the ML algorithms, the Adaptive Boosting classifier showed the highest specificity and best discrimination potential overall, with 80.4% ± 2.9% accuracy, 72.0% ± 5.6% sensitivity, 84.7% ± 3.8% specificity, and 0.812 ± 0.047 area under the receiver operating characteristic curve (AUC). The highest sensitivity was 85.7% ± 5.6%, reached by the Gaussian Naive Bayes model, and the best AUC was 0.854 ± 0.028 by the Extra Trees classifier. CONCLUSIONS: Feature extraction algorithms combined with ML approaches simplify the utilization of phase-contrast MRI. The highest-performing ML algorithm was Adaptive Boosting, which showed good calibration and discrimination on the testing data, with 80.4% accuracy, 72.0% sensitivity, 84.7% specificity, and 0.812 AUC. Phase-contrast MRI boosted by the ML approach can help to determine shunt-responsive iNPH patients.

Overview of cerebral cavernous malformations: comparison of treatment approaches.

OBJECTIVES: The comparison of treatment efficacy for cerebral cavernous malformations (CCMs) has not yet been well researched. DESIGN: PubMed, Cochrane Library, Science Direct, ISI Web of Science, Embase and additional sources were searched to identify cohort studies about the treatment of CCMs published between 1990 and 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed; the Newcastle-Ottawa Scale was used to assess the risk of bias and to evaluate limitations based on selection/outcome biases. The cumulative incidences with 95% CIs were calculated using the random effects model. The models of Poisson distribution were applied to evaluate risk factors of poorer treatment outcome by calculating rate ratios within 100 person-years with 95% CIs. RESULTS: A total of 100 cohorts yielding 8994 patients treated for CCMs within 41 098 person-years of follow-up were analysed. The efficacy of ensuring the prevention of haemorrhage was 97% in surgical, 86% in radiosurgical and 77% in the conservative treatment. The lowest mortality (1%) was after radiosurgery, and the highest persistent morbidity (22%) was in natural history series. Deep-seated and brainstem CCMs were associated with higher bleeding rates. Lobar localisation was a protective factor in all analyses. Patients with history of previous haemorrhage were exposed to higher risk of rebleeding. Male gender was a protective factor associated with lower risk of post-treatment haemorrhage. CONCLUSIONS: Surgical resection of CCM is effective in ensuring the prevention of haemorrhage with acceptable morbidity and mortality, but conservative and radiosurgical management is a justified treatment alternative. Brainstem and deep-seated CCMs are predominantly associated with higher haemorrhage rates.

First experiences with Miethke M.blue® valve in iNPH patients.

The literature on hydrocephalus treatment shows support for adjustable valves and devices which prevent the so-called "siphon effect". In our study, 21 probable iNPH patients were indicated to shunt surgery with the Miethke M.blue® adjustable gravitational valve. Outcomes at three months were measured using the following tests: Dutch Gait Scale, International Consortium on Incontinence Questionnaire (ICIQ-UI SF), SF12V2-Health Survey, Kiefer Scale, 3T MRI, and a neuropsychological testing battery. Preoperative parameters were studied for any signs of overdrainage risk. Valves were set according to the manufacturer's recommendations. Significant improvement at three months was seen in the Dutch Gait Scale, ICIQ-UI SF, Kiefer Scale, Mental Health Component of the SF12V2-Health Survey (MCS-12) and three neuropsychological tests: Rey-Osterrieth complex figure test (ROCFT 30 min), auditory verbal learning test (AVLT I-V) and the NKP version of verbal fluency test. Seven patients needed more than one adjustment of the valve. This subgroup significantly improved only in Walking Score and Step Score but the trend was toward significant improvement in other variables. Eight patients had subdural effusions that were completely managed with adjustments until the 3-month control. BMI was significantly lower in patients with ≥2 adjustments compared to those with a maximum of one adjustment. Implantation had low complication rates and no mortality. Initial results are promising however more studies are needed to provide rationale for gravitational valves in iNPH. We recommend increasing the initial valve setting by 2-4 cm H2O above manufacturer's recommendation, especially in lean patients.

Cerebral venous sinus thrombosis in infant with COVID-19.

We present a rare case of cerebral venous sinus thrombosis in a COVID-19-positive, 2-month-old infant, to this day the youngest described patient with this rare combination of findings. He was hospitalized with focal seizures. The first brain imaging showed subdural hematoma and focal ischemic changes. The subdural hematoma was successfully evacuated. The control imaging, done due to lethargy, showed an extensive cerebral venous sinus thrombosis. The thrombosis was managed with low molecular weight heparin leading to clinical and radiological improvement. With this case report, we would like to add to the information pool of COVID-19 neurological manifestations in children, particularly those younger than 1 year.

Prediction of Shunt Responsiveness in Suspected Patients With Normal Pressure Hydrocephalus Using the Lumbar Infusion Test: A Machine Learning Approach.

BACKGROUND: Machine learning (ML) approaches can significantly improve the classical Rout-based evaluation of the lumbar infusion test (LIT) and the clinical management of the normal pressure hydrocephalus. OBJECTIVE: To develop a ML model that accurately identifies patients as candidates for permanent cerebral spinal fluid shunt implantation using only intracranial pressure and electrocardiogram signals recorded throughout LIT. METHODS: This was a single-center cohort study of prospectively collected data of 96 patients who underwent LIT and 5-day external lumbar cerebral spinal fluid drainage (external lumbar drainage) as a reference diagnostic method. A set of selected 48 intracranial pressure/electrocardiogram complex signal waveform features describing nonlinear behavior, wavelet transform spectral signatures, or recurrent map patterns were calculated for each patient. After applying a leave-one-out cross-validation training-testing split of the data set, we trained and evaluated the performance of various state-of-the-art ML algorithms. RESULTS: The highest performing ML algorithm was the eXtreme Gradient Boosting. This model showed a good calibration and discrimination on the testing data, with an area under the receiver operating characteristic curve of 0.891 (accuracy: 82.3%, sensitivity: 86.1%, and specificity: 73.9%) obtained for 8 selected features. Our ML model clearly outperforms the classical Rout-based manual classification commonly used in clinical practice with an accuracy of 62.5%. CONCLUSION: This study successfully used the ML approach to predict the outcome of a 5-day external lumbar drainage and hence which patients are likely to benefit from permanent shunt implantation. Our automated ML model thus enhances the diagnostic utility of LIT in management.

Meningiomas in dogs.

BACKGROUND: Meningiomas and gliomas are the two most common types of human intracranial tumors. However, meningiomas are not exclusively human tumors and are often seen in dogs and cats. METHODS: To present meningioma surgery in dogs and compare the surgical possibilities, tumor location, and to show the differences between human and veterinary approaches to tumor profiling. Eleven dogs with meningiomas were treated surgically for 5 years. All tumors except one were resected radically (Simpson 2). Localization of tumors mirrored that of human meningiomas. RESULTS: Two dogs died in direct relation to surgery. One died 14 months after surgery due to tumor regrowth. Three dogs died of unrelated causes 10-36 months after tumor resection and five dogs are alive and tumor-free 2-42 months after surgery. CONCLUSION: Radical surgery in dogs is as effective as in humans. Thus, we propose that it should be implemented as first-line treatment. The article is meant to please all those overly curious neurosurgeons in the world.

From head micro-motions towards CSF dynamics and non-invasive intracranial pressure monitoring.

Continuous monitoring of the intracranial pressure (ICP) is essential in neurocritical care. There are a variety of ICP monitoring systems currently available, with the intraventricular fluid filled catheter transducer currently representing the "gold standard". As the placement of catheters is associated with the attendant risk of infection, hematoma formation, and seizures, there is a need for a reliable, non-invasive alternative. In the present study we suggest a unique theoretical framework based on differential geometry invariants of cranial micro-motions with the potential for continuous non-invasive ICP monitoring in conservative traumatic brain injury (TBI) treatment. As a proof of this concept, we have developed a pillow with embedded mechanical sensors and collected an extensive dataset (> 550 h on 24 TBI coma patients) of cranial micro-motions and the reference intraparenchymal ICP. From the multidimensional pulsatile curve we calculated the first Cartan curvature and constructed a "fingerprint" image (Cartan map) associated with the cerebrospinal fluid (CSF) dynamics. The Cartan map features maxima bands corresponding to a pressure wave reflection corresponding to a detectable skull tremble. We give evidence for a statistically significant and patient-independent correlation between skull micro-motions and ICP time derivative. Our unique differential geometry-based method yields a broader and global perspective on intracranial CSF dynamics compared to rather local catheter-based measurement and has the potential for wider applications.

Bilateral cortical stimulation for bilateral refractory atypical trigeminal neuropathic pain: Case report.

BACKGROUND: Atypical trigeminal neuropathic pain (aTNP) is a disabling clinical entity. If conservative treatment fails neuromodulation could be indicated. Motor cortex stimulation (MCS) has emerged as an alternative advanced management of such cases. CASE REPORT: We report a case of a patient with bilateral aTNP effectively treated with bilateral MCS. We describe case history, preoperative planning, surgical technique, follow-up and stimulation settings. The surgical technique and the settings used were both gradually adjusted according to current knowledge. CONCLUSIONS: The bilateral MCS led to substantial pain relief in a patient for whom previous pharmacological management had failed. Initial VAS 10/10 with attacks of acute pain was reduced to median VAS 2/10 (maximum VAS 5/10) without acute attacks since the second electrode parameters were set. The reported results for MCS treatment of TNP in the literature demonstrate good long-term efficacy with low complication rates. Although MCS remains to be an off-label procedure, our case demonstrates that in a well-chosen candidate this option could provide impressive results. Although no clear evidence is currently given, we believe that future studies will elucidate indication criteria, surgical technique and stimulation parameters for MCS so it could be offered in a regular basis to patients with refractory pain.

Role of DESH, callosal angle and cingulate sulcus sign in prediction of gait responsiveness after shunting in iNPH patients.

Primary endpoint of this single-centre, prospective consecutive cohort study was to evaluate DESH score, CA, CSS and Evans index of suspected iNPH patients against the reference standard of lumbar infusion test (LIT) and external lumbar drainage (ELD) in prediction of gait response after VP shunt implantation in patients with idiopathic normal pressure hydrocephalus (iNPH). Patients were assigned to NPH and non-NPH groups based on LIT and ELD results. Age-matched controls were added for group comparison. 32 NPH, 46 non-NPH and 15 control subjects were enrolled in the study. There were significant differences in mean preoperative DESH scores of NPH, non-NPH and control groups (6.3 ± 2.3 ([±SD]) (range 2-10) vs 4.5 ± 2.4 (range 0-10) vs 1.0 ± 1.2 (range 0-4)). Differences in mean CA and Evans index were not significant between NPH and non-NPH groups. CSS showed 62.5% sensitivity, 60.87% specificity, 52.63% PPV and 70% NPV for differentiation of NPH and non-NPH groups. A CA of 68 degrees had 48.49% sensitivity, 76.09% specificity, 59.26% PPV 67.31% NPV and DESH score of 4 had 93.75% sensitivity, 41.30% specificity, 52.63% PPV and 90.48% NPV for differentiation between NPH and non-NPH groups. The groups of probable iNPH patients with gait impairment diagnosed by high DESH score or positive functional testing did not overlap and DESH score did not correlate with gait improvement after ELD. DESH score should not be used as a simple diagnostic or prognostic marker of iNPH and we could not confirm the benefit of measurement of callosal angle and cingulate sulcus sign.

Structural volumetry in NPH diagnostics and treatment-future or dead end?

To assess automated volumetric analysis as a potential presurgical diagnostic tool or as a method to potentially shed light on normal pressure hydrocephalus (NPH) pathophysiology. MRI imaging according to our protocol was performed in 29 NPH patients, 45 non-NPH (but suspected) patients and 15 controls. Twenty patients underwent a second MRI 3 months after ventriculoperitoneal (VP) shunt surgery. All structures relevant to NPH diagnosis were automatically segmented using commercial software. The results were subsequently tested using ANOVA analysis. Significant differences in the volumes of the corpus callosum, left hippocampus, internal globus pallidus, grey and white matter and ventricular volumes were observed between NPH group and healthy controls. However, the differences between NPH and non-NPH groups were non-significant. Three months after, VP shunt insertion decreased ventricular volume was the only clearly significant result (p value 0.0001). Even though a detailed volumetric study shows several significant differences, volumetric analysis as a standalone method does not provide a simple diagnostic biomarker, nor does it shed a light on an unknown NPH aetiology.

Normal pressure hydrocephalus-an overview of pathophysiological mechanisms and diagnostic procedures.

Normal pressure hydrocephalus (NPH) is an important differential diagnosis of neurodegenerative diseases. The prevalence of dementia is increasing in line with the worldwide increase in life expectancy. NPH can be divided into idiopathic (iNPH) and secondary (sNPH) which is important in terms of clinical symptoms, future progress, and the outcome of possible treatment. The full clinical triad is not prevalent in all of the cases and the pathophysiology of iNPH remains unclear. Diagnosis is based on the evaluation of clinical symptoms (Hakim's triad) combined with an MRI assessment, evaluation of CSF dynamic parameters by different methods such as a tap test, lumbar infusion test (LIT), and external lumbar drainage (ELD). Despite the development of diagnostic techniques and strategies in management, NPH remains to be a challenge for the specialists despite more than 50 years of research. However, results of this research have brought new opportunities in the diagnosis, therapy, and quality of life as well as survival time of NPH patients with improved symptoms. The aim of this article is to present the pathophysiological hypotheses of NPH and an overview of the diagnostic techniques used for the evaluation of NPH patients.