Symptomatic spinal metastasis of a supratentorial glioblastoma in a pediatric patient: a case report and comprehensive review of the literature.

Spinal metastasis of Glioblastoma is a rare occurrence, especially in pediatric patients, and extremely rare to become symptomatic. The pathology is poorly understood and remains with unclear dissemination mechanisms. The treatment approaches are varied and multimodal therapy (surgery, chemotherapy, and radiotherapy) can be employed to manage this type of metastasis. We report a case of a 17-year-old female who underwent a gross-total resection of a right frontal glioblastoma and had adjuvant therapy with chemo- and radiotherapy. In the sixth month of follow-up, the patient presented a paraparesis, and a distant recurrence at T7-T8 was detected. The patient was treated with gross-total resection of the tumor through a laminectomy. The histopathological results were consistent with an isocitrate dehydrogenase (IDH) wildtype GBM metastasis. The patient was treated with multimodal therapy, including surgery, radiotherapy, and chemotherapy. A complementary comprehensive review of current available literature on this topic is also presented.

A Tailored Combined Petrosal Approach for the Resection of a Petroclival Meningioma With Pneumatized Apex: Checkmate to the Trigeminal Nerve: 2-Dimensional Operative Video.

Petroclival meningiomas are a challenge in skull base surgery, despite the advances in the knowledge of this pathology, there are still many controversies regarding their optimal treatment.1 The proximity and adherence to cranial nerves, major vessels such as the basilar artery, and brainstem compression explain the significant surgical risk.2,3 We present the case of a woman with a petroclival meningioma (WHO grade I) and pneumatization of the petrous apex. A tailored combined petrosal approach with a wide pedicled flap was performed for reconstruction of the pneumatized petrous apex. The decision to choose an appropriate surgical approach in this type of tumor depends on multiple factors including the surgeon's skill. We believe that in this particular case the pneumatization of the petrosal apex and the involvement of the trigeminal nerve by the tumor demanded a surgical approach that allowed a 360-degree view of the trigeminal nerve and at all angles of attack on the site of tumor implantation, we call this a checkmate of the trigeminal nerve. Transposition of the trigeminal nerve may be necessary in cases such as the one we present for adequate visualization of the petroclival region. This surgical video discusses the nuances of technique, surgical pearls, and anatomic landmarks in the combined petrosal approach. The patient consented to the procedure and to the publication of her image, and appropriate consent was obtained for publication of the cadaver's image.

The M-Point A Novel Landmark in Middle Fossa Surgery: A Cadaveric Morphometric Study.

BACKGROUND: The arcuate eminence (AE) is an anatomically consistent bony protrusion located on the upper surface of the petrous bone that has been previously studied as a reference for lateral skull base approaches. There is a paucity of information in the neurosurgical literature seeking to improve the safety of the extended middle cranial fossa (MCF) approach using detailed morphometric analysis of the AE. OBJECTIVE: To evaluate the use of the AE as an anatomical landmark to help with early identification of the internal acoustic canal (IAC) in MCF approaches by means of a cadaveric study, using a new morphometric reference termed the "M-point." METHODS: A total of 40 dry temporal bones and 2 formalin-preserved, latex-injected cadaveric heads were used. The M-point was established as a new anatomic reference by identifying the intersection of a line perpendicular to the alignment of the petrous ridge (PR), originating from the midpoint of the AE, with the PR itself. Subsequent anatomical measurements were performed to measure the distance between M-point and IAC. Additional distances, including PR length and the anteroposterior and lateral AE surfaces, were also measured. RESULTS: The mean distance between the M-point and the center of the IAC was 14.9 mm (SD ± 2.09), offering a safe drilling area during an MCF approach. CONCLUSIONS: This study provides novel information on identification of a new anatomic reference point known as the M-point that that can be used to improve early surgical identification of the IAC.

Preoperative tractography algorithm for safe resection of tumors located in the descending motor pathways zone.

Background: Diffusion tensor imaging (DTI) tractography facilitates maximal safe resection and optimizes planning to avoid injury during subcortical dissection along descending motor pathways (DMPs). We provide an affordable, safe, and timely algorithm for preoperative DTI motor reconstruction for gliomas adjacent to DMPs. Methods: Preoperative DTI reconstructions were extracted from a prospectively acquired registry of glioma resections adjacent to DMPs. The surgeries were performed over a 7-year period. Demographic, clinical, and radiographic data were extracted from patients' electronic medical records. Results: Nineteen patients (12 male) underwent preoperative tractography between January 1, 2013, and May 31, 2020. The average age was 44.5 years (range, 19-81 years). A complete radiological resection was achieved in nine patients, a subtotal resection in five, a partial resection in three, and a biopsy in two. Histopathological diagnoses included 10 patients with high-grade glioma and nine with low-grade glioma. A total of 16 perirolandic locations (10 frontal and six frontoparietal) were recorded, as well as two in the insula and one in the basal ganglia. In 9 patients (47.3%), the lesion was in the dominant hemisphere. The median preoperative and postoperative Karnofsky Performance Scores were 78 and 80, respectively. Motor function was unchanged or improved over time in 15 cases (78.9%). Conclusion: This protocol of DTI reconstruction for glioma removal near the DMP shows good results in low-term neurological functional outcomes.

Standardization of Strategies to Perform a Parafascicular Tubular Approach for the Resection of Brain Tumors in Eloquent Areas.

OBJECTIVE: The aim of this work is to define a methodological strategy for the minimally invasive tubular retractor (MITR) parafascicular transulcal approach (PTA) for the management of brain tumors sited in eloquent areas. METHODS: An observational prospective study was designed to evaluate the benefits of PTA associated with MITRs, tractography and intraoperative cortical stimulation. They study was conducted from June 2018 to June 2021. Information regarding white matter tracts was processed, preventing a potential damage during the approach and/or resection. All patients older than 18 years who had a single brain tumor lesion were included in the study. Patients with a preoperative Karnofsky Performance Scale (KPS) score greater than 70% and a Glasgow Coma Scale (GCS) score > 14 points were included. RESULTS: 72 patients were included in the study, the mean age was 49.6, the most affected gender was male, 12.5% presented aphasia, 11.1% presented paraphasia, 41.6% had motor deficit, 9.7% had an affection in the optic pathway, the most frequently affected region was the frontal lobe (26.3%), the most frequent lesions were high-grade gliomas (34.7%) and the measurement of the incisions was on average 5.58 cm. Of the patients, 94.4% underwent a total macroscopic resection and 90.2% did not present new postoperative neurological deficits. In all cases, a PTA was used. CONCLUSION: Tubular minimally invasive approaches (MIAs) allow one to perform maximal safe resection of brain tumors in eloquent areas, through small surgical corridors. Future comparative studies between traditional and minimally invasive techniques are required to further investigate the potential of these surgical nuances.

The Hibiscus Model: A Feasible Cadaveric Model Using Continuous Arterial Circulation for Intracranial Bypass Training and Its Validation.

OBJECTIVE: The frequency of intracranial bypass procedures has declined. Thus it is difficult for neurosurgeons to develop the necessary skills for this complex procedure. We present a perfusion-based cadaveric model to provide a realistic training experience with high anatomic and physiological fidelity, as well as instantaneous assessment of bypass patency. Validation was assessed by evaluating the educational impact and skill improvement of the participants. METHODS: Fourteen participants attended a hands-on revascularization course with 7 cadaveric models connected to a continuous arterial circulation system pumping a red-colored solution through the entire cranial vasculature, mimicking blood circulation. The ability to perform a vascular anastomosis was evaluated initially. Further, a questionnaire on prior experience was provided. At the end of the 36-hour course, the ability to perform an intracranial bypass was reexamined and the participants completed a self-assessment questionnaire. RESULTS: Initially, only 3 attendees were able to perform an end-to-end anastomosis within the time limit, and only 2 of these anastomoses showed adequate patency. After having accomplished the course, all participants were able to complete a patent end-to-end anastomosis within the time limit, thus demonstrating a significant improvement. Further, both overall educational gain and surgical skills were regarded as remarkable (n = 11 and n = 9). CONCLUSIONS: Simulation-based education is considered an important aspect of medical and surgical development. The presented model is a feasible and accessible alternative to the prior models used for cerebral bypass training. This training may serve as a helpful and widely available tool to improve neurosurgeons' development irrespective of financial resources.

Postnatal Surgical Correction of Myelomeningoceles: Preoperative and Intraoperative Risk Factors Associated with Postoperative Neurologic Outcomes.

OBJECTIVE: Open spina bifida or myelomeningocele (MMC) is a congenital defect that results from failure of caudal neurulation. We present a case series of patients who were treated with postnatal surgical correction for MMC, evaluating the possible preoperative and intraoperative risk factors associated with neurologic outcomes. METHODS: A retrospective chart review of patients who underwent postnatal surgical correction for MMCs over 11 years at our institution was performed. MMCs were classified based on their morphologic configuration into 3 types. Type I includes defects without a sac and there is cerebrospinal fluid (CSF) leak. Type II includes where there is a sac ≤4 cm, with or without CSF leak. Type III includes defects with a sac that are greater than 4 cm. RESULTS: Fifty patients were included. The median age of gestation at surgery was 37.4 weeks. There were 30 females (60%). All mothers received adequate folate supplementation. All patients underwent surgical correction in the first 48 hours. Lower extremity motor function at the last clinical follow-up was normal in 34 patients (68%). CSF leak, infection, and mortality were 8%, 2%, and 0%, respectively. Twenty-one patients (42%) underwent ventriculoperitoneal shunt for hydrocephalus. CONCLUSIONS: Despite there being no statistically significant associations with a timely closure, all cases were treated within the first 48 hours and this could influence the low complication rate. Individuals of Hispanic background who received appropriate folate supplementation still had high rates of MMC and we posit that this may be caused in part by a genetic/molecular predisposition.

Treatment Limitations for Pediatric Diffuse Intrinsic Pontine Gliomas in a Middle-Income Country.

Objectives To evaluate the surgical management outcomes in pediatric patients with diffuse intrinsic pontine gliomas (DIPGs) who underwent intended biopsies and partial resections in a middle-income country, highlighting the barriers and challenges of these procedures for further investigation. Methods A retrospective review of a prospective acquired series of patients who underwent biopsy or resection for DIPG between January 2012 and June 2018 at our institution was performed. Results A total of 43 patients with posterior fossa tumors were identified. From these, seven pediatric DIPG cases were enrolled. Five were males. The median age was 5 years (range: 1-12 years). Only one patient (14.3%) had a ganglioglioma, while the others presented pilocytic and diffuse astrocytomas. Two (28.6%) patients had an intentional biopsy, and the other five (71.4%) had a partial resection. In the three (28.6%) patients who presented with associated hydrocephalus, the endoscopic third ventriculostomy was performed in the same surgical time. The median preoperative Lansky play-performance scale (LPPS) was 80 (range: 60-100), while the median postoperative LPPS was 23 (range: 7-52). Conclusion A decrease in overall survival was noted compared with data reported in other series. Multifactorial barriers were discussed including the social, geographic, and economic features that may influence on final outcomes.

Resección Tubular Microquirúrgica de un Subependimoma Extenso del Ventrículo Lateral Izquierdo: Video Operatorio en 2D / Microsurgical Tubular Resection of an Extensive Subependymoma of the Left Lateral Ventricle: Operative Video in 2D

Introducción: Los subependimomas intracraneales son raros, representan el 0.2-0.7% de todos los tumores del sistema nervioso central1,2 y se originan en los ventrículos laterales en el 30-40% de los casos.3 Los síntomas usualmente se asocian a hipertensión endocraneana secundaria a hidrocefalia obstructiva.4 La resección completa del tumor es curativa en esta patología.5 El abordaje trans-surcal es seguro para lesiones ventriculares profundas y el uso de los retractores tubulares minimizan la retracción del parénquima cerebral evitando la compresión directa con valvas. Esto permite disminuir la presión del tejido cerebral que puede ocluir los vasos y producir isquemia local generando una lesión neurológica permanente. Descripción del caso: Se presenta el caso de una paciente de 66 años, diestra, con cefalea crónica que aumenta en frecuencia en el último mes. La resonancia cerebral contrastada muestra un tumor extenso en el ventrículo lateral izquierdo con signos de hidrocefalia obstructiva. Intervención: Se coloca la paciente en posición supina. Se hace una incisión bicoronal y se hace un abordaje trans-surcal F1/F2 izquierdo. Se coloca un retractor tubular guiado con el puntero de neuronavegación, introduciéndolo directamente en el parénquima cerebral y fijándolo al soporte de Leyla. Se colocó un catéter de ventriculostomía contralateral y se retira a las 48 horas sin complicaciones asociadas. La resonancia contrastada postoperatoria demuestra una resección completa del tumor. El análisis de patología reveló un subependimoma grado I de la clasificación de la Organización Mundial de la Salud. La paciente presentó transitoriamente apatía y pérdida del control del esfínter urinario que resolvieron completamente a las 3 semanas después de la cirugía. Se firmó un consentimiento firmado para la publicación de la información utilizada en este trabajo. Conclusión: La resección completa microscópica de un subependimoma extenso del ventrículo lateral izquierdo es factible a través de un abordaje tubular transulcal.

Introduction: Intracranial subependymomas are rare, representing only 0.2-0.7% of all central nervous system tumors1,2 and arise in the lateral ventricles in 30-40% of the cases.3 Symptoms depend on tumor location and usually arise when the cerebrospinal fluid (CSF) is blocked, generating a consequent intracranial hypertension.4 Microsurgical gross-total resection is possible and curative for these tumors.5 The transcortical/trans-sulcal approach is a safe approach for the access of deep-seated intraventricular lesions. The use of tubular retractor systems minimizes retraction injury when passing through the cortex and deep white matter tracts. This allows a decrease in the pressure on brain tissue that can occlude the brain vessels and produce local ischemia and a consequent permanent neurological injury. Case description: This is a case of a 66-year-old woman who presented chronic headaches that increased in frequency in the last month. Enhanced-brain MRI demonstrated a large left ventricular lesion with signs of obstructive hydrocephalus. Procedure: Patient was positioned supine. A bicoronal incision was used to perform a left frontal craniotomy. An F1/F2 transcortical/trans-sulcal approach was used. A guided tubular retractor is placed with the neuronavigation pointer, inserting it directly into the brain parenchyma and fixing it to the Leyla support. Postoperative postcontrast MRI demonstrated a complete resection of the tumor. Histopathological analysis revealed a subependymoma (World Health Organization Grade I). The patient presented transient apathy and loss of urinary sphincter control that completely resolved 3 weeks after surgery. Written informed consent was obtained for publication of information used for this work. Conclusions: A complete microsurgical resection of a large left ventricular subependymoma is feasible through a trans-sulcal tubular approach.