Augmented reality (AR) is a technological tool that superimposes two-dimensional virtual images onto three-dimensional real-world scenarios through the integration of neuronavigation and a surgical microscope. The aim of this study was to demonstrate our initial experience with AR and to assess its application in oncological neurosurgery. This is a case series with 31 patients who underwent surgery at Santa Casa BH for the treatment of intracranial tumors in the period from March 4, 2022, to July 14, 2023. The application of AR was evaluated in each case through three parameters: whether the virtual images auxiliated in the incision and craniotomy and whether the virtual images aided in intraoperative microsurgery decisions. Of the 31 patients, 5 patients developed new neurological deficits postoperatively. One patient died, with a mortality rate of 3.0%. Complete tumor resection was achieved in 22 patients, and partial resection was achieved in 6 patients. In all patients, AR was used to guide the incision and craniotomy in each case, leading to improved and precise surgical approaches. As intraoperative microsurgery guidance, it proved to be useful in 29 cases. The application of AR seems to enhance surgical safety for both the patient and the surgeon. It allows a more refined immediate operative planning, from head positioning to skin incision and craniotomy. Additionally, it helps decision-making in the intraoperative microsurgery phase with a potentially positive impact on surgical outcomes.

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.

The cortical bone trajectory (CBT) technique has emerged as a minimally invasive approach for lumbar fusion but may result in pseudoarthrosis and hardware failure. This report presents a case of successful pedicle screw revision in a patient with previous failed L2 and L3 fusion using a novel \"two-step\" technique, including (1) drilling a new trajectory with Medtronic EM800N Stealth MIDAS Navigated MR8 drill system (Medtronic, Dublin, Ireland) and (2) placement of Solera 4.75 ATS (awl-tapped screws) with navigated POWEREASE™ (Medtronic), described here for the first time. This method involves utilizing neuronavigation and specialized instruments to safely place pedicle screws through the path of the old cortical screw trajectory, addressing the challenges associated with CBT hardware failure.

Intracranial metastasis disease (IMD) has proven to be a frequent secondary occurrence, usually for primary cancers such as lung, breast, and melanoma, which have a high possibility of metastasizing to the brain. Due to the reasons listed above, treatment and early diagnosis are incredibly challenging. In the past decade, medicine has developed much better imaging solutions and radiological and surgical approaches, increasing the postoperative survival prognosis and achieving more time-efficient results. It is still exceptionally difficult to be able to prevent what type of metastasis a patient might develop other than by using the tumor type or subtype. We present a case of a 51-year-old female patient entering the Neurosurgical Clinic at the University Hospital \"St. Ivan Rilski\" for operative treatment of a second metastatic lesion located on the left parietal lobe in January 2024. She had previously had an operative resection of an initial lesion located on the left temporal lobe in December 2023. Her medical history began in 2015 when her first diagnosis was a breast carcinoma, followed by operative treatment and radio-, chemo-, and targeted therapy. In 2020, due to metastases located in the bones, she had to undergo another treatment with chemotherapy as well as have a total hysterectomy done as a result of another metastasis. The patient did not provide any family history, nor did she confirm any past or current allergies to foods, drugs, etc. Under general inhalation anesthesia, the patient was placed in a park bench position to the right and had a Mayfield head holder applied. Through a left parietal craniotomy and neuronavigation, a tumor formation was revealed with the characteristic of a secondary lesion. A gross total resection was achieved through a microsurgical technique. Postoperatively, there were no further complications observed in the patient, and she was discharged on day five from the hospital with relief of her symptoms.

Augmented reality (AR) is an emerging technology that can display three-dimensional patient anatomy in the surgeons\' field of view. The use of this technology has grown considerably for both presurgical and intraoperative guidance. A patient diagnosed with breast cancer started to experience numbness in the left hand, which progressed to weakness in the left hand and arm. An MRI was performed demonstrating a 2.9 cm X 1.8 cm lesion with extensive surrounding edema in the posterior fronto-parietal lobes. Surgery was recommended for presumed metastatic disease. Preoperatively, an AR system and Brainlab navigation were registered to the patient. AR, traditional navigation, and ultrasound were all used to localize the lesion and determine the craniotomy site and size. The tumor was removed along the direction of the lesion. Intraoperatively, we used AR to reexamine the tumor details and could appreciate that we had to redirect our surgical trajectory anteriorly and laterally in order to follow along the main axis of the tumor. In doing this, we were able to more confidently remain with the tumor, which by this time was poorly defined by 2D navigation and by direct vision. Postoperative MRI confirmed gross total removal of the tumor. The patient had an uneventful postoperative course with resolution of preoperative symptoms and the final surgical pathology was grade 4 glioblastoma. Here, we describe the valuable use of AR for the resection of a glioma. The system has a seamless registration process and provides the surgeon with a unique view of 3D anatomy overlaid onto the patient\'s head. This exciting technology can add tremendous value to complex cranial surgeries.

BACKGROUND: Ependymal cysts (EC) typically present supra-tentorially near the lateral ventricle, juxta ventricular, or temporoparietal regions. Previous cases have also identified infratentorial EC of the brainstem, cerebellum, and subarachnoid spaces. They are mostly asymptomatic. In this paper, we present the first-ever case of a symptomatic medullary ependymal cyst treated with surgery, along with a comprehensive review of the literature on EC of other parts of the brain stem.
METHODS: This 51-year-old female presented with hearing loss, dizziness, diplopia, and ataxia. Radiographic imaging indicated the presence of a non-enhancing lesion in the medulla with a mass effect on the brainstem. Pathological examination confirmed its characterization as an ependymal cyst. The patient underwent a suboccipital craniotomy for the fenestration of the medullary ependymal cyst under neuro-navigation, Intra-op ultrasound and intra-operative neuro-monitoring. Histopathological examination confirmed the diagnosis of an ependymal cyst. At one month follow-up, her KPS is 90, ECOG PS 1, and her ataxia has improved with complete resolution of diplopia.
CONCLUSIONS: Due to their rarity and potential similarity to other cystic structures, EC may be overlooked or incorrectly diagnosed resulting in mismanagement and surgical disaster. Therefore, a comprehensive understanding and awareness of their distinct characteristics are essential for accurate diagnosis and appropriate management.

OBJECTIVE: Robot-assisted biopsies have gained popularity in the last years. Most robotic procedures are performed with a floor-based robotic arm. Recently, Medtronic Stealth Autoguide, a miniaturized robotic arm that work together with an optical neuronavigation system, was launched. Its application in pediatric cases is relatively unexplored. In this study, we retrospectively report our experience using the Stealth Autoguide, for frameless stereotactic biopsies in pediatric patients.
METHODS: Pediatric patients who underwent stereotactic biopsy using the Stealth Autoguide cranial robotic platform from July 2020 to May 2023 were included in this study. Clinical, neuroradiological, surgical, and histological data were collected and analyzed.
RESULTS: Nineteen patients underwent 20 procedures (mean age was 9-year-old, range 1-17). In four patients, biopsy was part of a more complex surgical procedure (laser interstitial thermal therapy - LITT). The most common indication was diffuse intrinsic brain stem tumor, followed by diffuse supratentorial tumor. Nine procedures were performed in prone position, eight in supine position, and three in lateral position. Facial surface registration was adopted in six procedures, skull-fixed fiducials in 14. The biopsy diagnostic tissue acquisition rate was 100% in the patients who underwent only biopsy, while in the biopsy/LITT group, one case was not diagnostic. No patients developed clinically relevant postoperative complications.
CONCLUSIONS: The Stealth Autoguide system has proven to be safe, diagnostic, and highly accurate in performing stereotactic biopsies for both supratentorial and infratentorial lesions in the pediatric population.

Mucopolysaccharidosis type II (MPS II) results from the genetic deficiency of a lysosomal enzyme and is associated with central nervous system (CNS) dysfunction. In Japan, in addition to intravenous enzyme administration, intracerebroventricular enzyme delivery through the Ommaya reservoir has recently gained approval. Nevertheless, the ideal approach for safely implanting the reservoir into the narrow ventricles of infantile MPS II patients remains uncertain. In this report, we present two cases of successful reservoir placement in infantile MPS II patients using ultrasound guidance via the anterior fontanelle, coupled with flameless electromagnetic neuronavigation.

Odontoid fractures, frequently observed in patients over the age of 70, often involve the base of the axis (Anderson-D\'Alonzo type 2). For surgical treatment, posterior C1-C2 fixation is the traditional method, whose fusion rates range between 93 and 100%. However, morbidity and mortality rates are high. In addition, cervical motion, especially axial rotation, is postoperatively reduced. Nakanishi and Bohler introduced the anterior screw fixation approach for the surgical treatment of odontoid fracture type II. This procedure preserves the atlantoaxial complex motion, provides immediate stability and high fracture healing rates, and, most importantly, has a low incidence of complications with good fusion rates. The surgical strategy must take into account the patient\'s anatomy, the morphological characteristics of the fracture, the quality of the bone, and any concomitant injuries. In this chapter, we describe a C2 type II fracture treated via a neuronavigated anterior retropharyngeal approach.

A Meckel\'s cave tumor poses a great challenge because of the peculiar neurovascular structure of the area and the deep location. Multiple surgical approaches have been designed for this area. In this report, we describe a case treated with a combined one step single piece fronto-temporo-orbito-zygomatic craniotomy (FTOZ) endoscopic-assisted approach for the treatment of an epidermoid tumor of Meckel\'s cave. A 51-year-old woman presented with a clinical history of left trigeminal neuralgia and paresthesia. CT imaging revealed a left basal temporal tumor. MR showed a tumor located in Meckel\'s cave near the cavernous sinus, with a good enhancement after gadolinium administration. The tumor was resected through a lateral basal subtemporal extradural approach followed by an intradural approach using intraoperative neuronavigation, endoscopic assistance, neurophysiological monitoring, and an intraoperative ultrasound probe. The lesion was completely removed. No new onset neurological damage has occurred. The symptoms improved following surgery. The aesthetic appearance of the patient was respected. The combined approach with a single piece fronto-temporo-orbito-zygomatic craniotomy has enabled us to work on a wider operating field to completely remove the lesion avoiding blind spots.