BACKGROUND: Intraoperative ultrasound (IOUS) is a profitable tool for neurosurgical procedures\' assistance, especially in neuro-oncology. It is a rapid, ergonomic and reproducible technique. However, its known handicap is a steep learning curve for neurosurgeons. Here, we describe an interesting postoperative analysis that provides extra feedback after surgery, accelerating the learning process.
METHODS: We conducted a descriptive retrospective unicenter study including patients operated from intra-axial brain tumors using neuronavigation (Curve, Brainlab) and IOUS (BK-5000, BK medical) guidance. All patients had preoperative Magnetic Resonance Imaging (MRI) prior to tumor resection. During surgery, 3D neuronavigated IOUS studies (n3DUS) were obtained through craniotomy N13C5 transducer\'s integration to the neuronavigation system. At least two n3DUS studies were obtained: prior to tumor resection and at the resection conclusion. A postoperative MRI was performed within 48 h. MRI and n3DUS studies were posteriorly fused and analyzed with Elements (Brainlab) planning software, permitting two comparative analyses: preoperative MRI compared to pre-resection n3DUS and postoperative MRI to post-resection n3DUS. Cases with incomplete MRI or n3DUS studies were withdrawn from the study.
RESULTS: From April 2022 to March 2024, 73 patients were operated assisted by IOUS. From them, 39 were included in the study. Analyses comparing preoperative MRI and pre-resection n3DUS showed great concordance of tumor volume (p < 0,001) between both modalities. Analysis comparing postoperative MRI and post-resection n3DUS also showed good concordance in residual tumor volume (RTV) in cases where gross total resection (GTR) was not achieved (p < 0,001). In two cases, RTV detected on MRI that was not detected intra-operatively with IOUS could be reviewed in detail to recheck its appearance.
CONCLUSIONS: Post-operative comparative analyses between IOUS and MRI is a valuable tool for novel ultrasound users, as it enhances the amount of feedback provided by cases and could accelerate the learning process, flattening this technique\'s learning curve.

BACKGROUND: Transcranial focused ultrasound (tFUS) neuromodulation has shown promise in animals but is challenging to translate to humans because of the thicker skull that heavily scatters ultrasound waves.
OBJECTIVE: We develop and disseminate a model-based navigation (MBN) tool for acoustic dose delivery in the presence of skull aberrations that is easy to use by non-specialists.
METHODS: We pre-compute acoustic beams for thousands of virtual transducer locations on the scalp of the subject under study. We use the hybrid angular spectrum solver mSOUND, which runs in ∼4 s per solve per CPU yielding pre-computation times under 1 h for scalp meshes with up to 4000 faces and a parallelization factor of 5. We combine this pre-computed set of beam solutions with optical tracking, thus allowing real-time display of the tFUS beam as the operator freely navigates the transducer around the subject\' scalp. We assess the impact of MBN versus line-of-sight targeting (LOST) positioning in simulations of 13 subjects.
RESULTS: Our navigation tool has a display refresh rate of ∼10 Hz. In our simulations, MBN increased the acoustic dose in the thalamus and amygdala by 8-67 % compared to LOST and avoided complete target misses that affected 10-20 % of LOST cases. MBN also yielded a lower variability of the deposited dose across subjects than LOST.
CONCLUSIONS: MBN may yield greater and more consistent (less variable) ultrasound dose deposition than transducer placement with line-of-sight targeting, and thus could become a helpful tool to improve the efficacy of tFUS neuromodulation.

BACKGROUND: Surgical treatment for trigeminal neuralgia includes percutaneous techniques, including balloon compression, first described in 1983 by Mullan and Lichtor (J Neurosurg 59(6):1007-1012, 6).
METHODS: Here we present a safe and simple navigation-assisted percutaneous technique for balloon compression, which can also be used for glycerol injection.
CONCLUSIONS: The navigation-assisted percutaneous technique for balloon compression for trigeminal neuralgia is a quick and safe treatment for patients not candidates for microvascular decompression.

BACKGROUND: Non-invasive brain mapping using navigated transcranial magnetic stimulation (nTMS) is a valuable tool prior to resection of malignant brain tumors. With nTMS motor mapping, it is additionally possible to analyze the function of the motor system and to evaluate tumor-induced neuroplasticity. Distinct changes in motor cortex excitability induced by certain malignant brain tumors are a focal point of research.
METHODS: A retrospective single-center study was conducted involving patients with malignant brain tumors. Clinical data, resting motor threshold (rMT), and nTMS-based tractography were evaluated. The interhemispheric rMT-ratio (rMTTumor/rMTControl) was calculated for each extremity and considered pathological if it was >110% or <90%. Distances between the corticospinal tract and the tumor (lesion-to-tract-distance - LTD) were measured.
RESULTS: 49 patients were evaluated. 16 patients (32.7%) had a preoperative motor deficit. The cohort comprised 22 glioblastomas (44.9%), 5 gliomas of Classification of Tumors of the Central Nervous System (CNS WHO) grade 3 (10.2%), 6 gliomas of CNS WHO grade 2 (12.2%) and 16 cerebral metastases (32.7%). 26 (53.1%) had a pathological rMT-ratio for the upper extremity and 35 (71.4%) for the lower extremity. All patients with tumor-induced motor deficits had pathological interhemispheric rMT-ratios, and presence of tumor-induced motor deficits was associated with infiltration of the tumor to the nTMS-positive cortex (p = 0.04) and shorter LTDs (all p < 0.021). Pathological interhemispheric rMT-ratio for the upper extremity was associated with cerebral metastases, but not with gliomas (p = 0.002).
CONCLUSIONS: Our study underlines the diagnostic potential of nTMS motor mapping to go beyond surgical risk stratification. Pathological alterations in motor cortex excitability can be measured with nTMS mapping. Pathological cortical excitability was more frequent in cerebral metastases than in gliomas.

BACKGROUND: In assessing the clinical utility and safety of 3.0 T intraoperative magnetic resonance imaging (iMRI) combined with multimodality functional MRI (fMRI) guidance in the resection of functional area gliomas, we conducted a study.
METHODS: Among 120 patients with newly diagnosed functional area gliomas who underwent surgical treatment, 60 were included in each group: the integrated group with iMRI and fMRI and the conventional navigation group. Between-group comparisons were made for the extent of resection (EOR), preoperative and postoperative activities of daily living based on the Karnofsky performance status, surgery duration, and postoperative intracranial infection rate.
RESULTS: Compared to the conventional navigation group, the integrated navigation group with iMRI and fMRI exhibited significant improvements in tumor resection (complete resection rate: 85.0% vs. 60.0%, P = 0.006) and postoperative life self-care ability scores (Karnofsky score) (median ± interquartile range: 90 ± 25 vs. 80 ± 30, P = 0.013). Additionally, although the integrated navigation group with iMRI and fMRI required significantly longer surgeries than the conventional navigation group (mean ± standard deviation: 411.42 ± 126.4 min vs. 295.97 ± 96.48 min, P<0.0001), there was no significant between-group difference in the overall incidence of postoperative intracranial infection (16.7% vs. 18.3%, P = 0.624).
CONCLUSIONS: The combination of 3.0 T iMRI with multimodal fMRI guidance enables effective tumor resection with minimal neurological damage.

OBJECTIVE: This study aims to assess the efficacy and limitations of Computed Tomography Angiography (CTA)-based 3D virtual models for preoperative simulation and intraoperative neuronavigation in the surgical treatment of Distal Anterior Cerebral Artery (DACA) Aneurysms.
METHODS: A retrospective observational study was conducted, analyzing patients who underwent surgical clipping of DACA aneurysms via an interhemispheric approach from 2016 to 2022. Outcomes measured included qualitative analyses of 3D reconstructions against actual intraoperative anatomy, neuronavigator accuracy, 6-month modified Rankin Scale (mRS), complete exclusion rates, and surgical complications. Patient demographics, clinical characteristics, surgical timing, and intraoperative data were meticulously documented for analysis.
RESULTS: Fifteen patients were included in the study, with a mean age of 52 years. The mean Hunt-Hess score at admission was 2.2, encompassing 2 unruptured and 13 ruptured aneurysms. Intraoperative anatomical visualization perfectly matched the preoperative 3D model in 13 cases, with discrepancies in two. Neuronavigation demonstrated a mean accuracy of 1.76 mm, remaining consistent in 14 patients, and accurately tracking the planned trajectory. Postoperative complications occurred in 26.5 % of patients, including two fatalities, with no navigation-related complications. Incomplete aneurysm occlusion was observed in one case. The mean mRS score at 6 months was 2.46.
CONCLUSIONS: The employment of 3D CTA for preoperative simulation and intraoperative neuronavigation holds significant potential in enhancing the surgical management of DACA aneurysms. Despite some discrepancies and technical limitations, the overall precision of preoperative simulations and the strategic value of intraoperative neuronavigation highlight their utility in improving surgical outcomes.

Due to a unique cortical venous drainage pattern without sinus drainage, ethmoidal dural arteriovenous fistula (DAVF) are uncommon cerebral vascular lesions that carry a high risk of brain bleeding and neurologic deficit. Surgical intervention has been found to have a lower complication rate and a more satisfactory obliteration rate than endovascular treatment among the various DAVF treatment options. The supraorbital keyhole subfrontal approach is one of the least invasive and appropriate surgical techniques for addressing the anterior fossa vascular lesion in eDAVFs. We describe two men, ages 60 and 71, who underwent this surgical intervention to treat asymptomatic Cognard type IV eDAVFs. Complete obliteration with a detached fistulous point and skeletonization was accomplished with the aid of intraoperative neuronavigation. Thus, we suggest that a suitable surgical method for the treatment of eDAVFs would be to use a supraorbital keyhole subfrontal approach.

UNASSIGNED: Pharmacoresistant epilepsy is a multicomponent disease that can be successfully treated surgically if the surgical tactics are properly defined. We present the first case of stimulation of anterior thalamic nuclei in pharmacoresistant epilepsy in Kazakhstan. This will be a new opportunity for Kazakhstanis diagnosed with epilepsy to achieve stable epilepsy remission.
UNASSIGNED: The patient was born in 2000. The first episode of tonic clonic seizures with loss of consciousness occurred in 2014. Repeatedly underwent therapeutic and diagnostic measures in the neurological department. The frequency of seizures increased in dynamics. The results of instrumental examination revealed the following morphological changes: Morphological changes: Focal cortical dysplasia (FCD) in the left cingulate gyrus, hypometabolism in the left thalamus and forehead, signs of hippocampal sclerosis on both sides. Electroencephalogram (EEG) shows activity in frontal areas on both sides, more on the right. Based on clinical and instrumental data according to the 2017 ILAE classification, the diagnosis was Structural focal frontal lobe epilepsy with bilateral tonic-clonic seizures. FCD of the left cingulate gyrus. Resistance to antiepileptic therapy.
UNASSIGNED: The patient was hospitalized in the department of neurosurgery. In light of the evidence indicating structural changes in the brain substance and ambiguous EEG findings, the indications for deep brain stimulation (DBS) of the anterior nucleus (ANT) were made. Electrode implantation was performed under general anesthesia, and preoperative computer tomography (CT) scans were performed using the CRW® stereotactic system in combination with magnetic resonance imaging (MRI) scans using Brainlab Neuronavigation with 3D Atlas to identify the anterior thalamic nuclei.
UNASSIGNED: The observed structural changes in the brain substance and the ambiguous EEG results call into question the efficacy of surgical procedures aimed at removing existing foci or destroying them. Based on the above, as well as the experience of foreign colleagues, the choice of neurosurgeons was DBS ANT. Although the selection of ideal candidates for thalamic stimulation is still controversial, in the described case we were able to achieve control of seizure activity. The patient was seizure free for 2 months after surgery. The patient was discharged on postoperative day 7.

OBJECTIVE: Neuronavigation, explored as an intra-operative adjunct for brain tumor surgery three decades ago, has become globally utilized with a promising upward trajectory. This study aims to chart its success from idea to adoption and evolution within the US and globally.
METHODS: A three-pronged methodology included a systematic literature search, impact analysis using NIH relative citation ratio (RCR) and Altmetric scores, and assessment of patent holdings. Data was dichotomized for US and international contexts.
RESULTS: The first neuronavigation publication stemmed from Finland in 1993, marking its inception. Over three decades, the cumulative number of 323 studies, along with the significantly increasing publication trend (r = 0.74, p < 0.05) and distribution across 34 countries, underscored its progressive and global adoption. Neuronavigation, mostly optical systems (58%), was utilized in over 19,000 cases, predominantly for brain tumor surgery (84%). Literature impact showed a robust cumulative median RCR score surpassing that for NIH-funded studies (1.37 vs. 1.0), with US studies having a significantly higher median RCR than international (1.71 vs. 1.21, p < 0.05). Technological evolution was characterized by adjuncts, including micro/exo/endoscope (21%), MRI (17%), ultrasound (10%), and CT (7%). Patent analysis demonstrated academic and industrial representation with an interdisciplinary convergence of medical and computational sciences.
CONCLUSIONS: Since its inception thirty years ago, neuronavigation has been adopted worldwide, and it has evolved with adjunct technology integration to enhance its meaningful use. The current neuronavigation innovation pipeline is progressing, with academic and industry partnering to advance its further application in treating brain tumor patients.

UNASSIGNED: The advancement of pituitary surgery has rendered it a secure and efficient treatment method; nevertheless, the potential for incomplete tumor removal and cerebrospinal fluid (CSF) leak remains. Neuronavigation-assisted pituitary neuroendocrine tumor (PitNET) resections have been driving a rising number of attentions in recent years. However, there is currently a lack of comprehensive quantitative evaluation of the effectiveness of neuronavigation-assisted pituitary tumor resection. We aimed to assess the curative effects and complications with or without the use of an image-based neuronavigation in PitNET resection.
UNASSIGNED: A systematic review and meta-analysis was performed by searching PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus from inception until May 1, 2024 in English to identify any studies reporting gross total resection (GTR) or postoperative complications in patients who underwent neuronavigation-assisted PitNET resection, excluding conference abstracts and studies with fewer than five subjects. We also searched the reference lists of previous systematic reviews and other relevant publications in databases. We reviewed and analyzed the studies that investigated the operative effects and complications of neuronavigation in PitNET resection. Study quality was assessed by the Newcastle-Ottawa scale, and publication bias was evaluated by funnel plot. Review manager 5.3 was employed for meta-analysis. The results were expressed as odds ratio (OR) with 95% confidence interval (CI) of image-assisted techniques for the incidence of GTR and complications.
UNASSIGNED: A total of 42 publications that fulfilled the established searching criteria were obtained from the above-mentioned databases, all of which with the Newcastle-Ottawa Scale scores ≥ six ★. Among the included publications, 37 studies indicated that the OR of image-based neuronavigation was 2.29 (95% CI: 2.02-2.60, P<0.00001, I2=24%) for GTR. The other five studies compared the neuronavigation group (experimental group) and non-neuronavigation group (control group), exhibiting high heterogeneity (I2=91%). After sensitivity analysis, the results showed that the rate of the CSF leak of the neuronavigation group was slightly lower than that of the non-neuronavigation group (OR: 0.84, 95% CI: 0.73-0.97, P=0.01, I2=43%).
UNASSIGNED: According to the existing data, neuronavigation-assisted PitNET resection can increase the rates of GTR and reduce the incidence of postoperative complications. Our results provide a reference for the selection of surgical methods for PitNET resection in future clinical practice.