The role of focused ultrasound for pediatric brain tumors: current insights and future implications on treatment strategies.

INTRODUCTION: Focused ultrasound (FUS) is an innovative and emerging technology for the treatment of adult and pediatric brain tumors and illustrates the intersection of various specialized fields, including neurosurgery, neuro-oncology, radiation oncology, and biomedical engineering. OBJECTIVE: The authors provide a comprehensive overview of the application and implications of FUS in treating pediatric brain tumors, with a special focus on pediatric low-grade gliomas (pLGGs) and the evolving landscape of this technology and its clinical utility. METHODS: The fundamental principles of FUS include its ability to induce thermal ablation or enhance drug delivery through transient blood-brain barrier (BBB) disruption, emphasizing the adaptability of high-intensity focused ultrasound (HIFU) and low-intensity focused ultrasound (LIFU) applications. RESULTS: Several ongoing clinical trials explore the potential of FUS in offering alternative therapeutic strategies for pathologies where conventional treatments fall short, specifically centrally-located benign CNS tumors and diffuse intrinsic pontine glioma (DIPG). A case illustration involving the use of HIFU for pilocytic astrocytoma is presented. CONCLUSION: Discussions regarding future applications of FUS for the treatment of gliomas include improved drug delivery, immunomodulation, radiosensitization, and other technological advancements.

Medulloblastomas, CNS embryonal tumors, and cerebellar mutism syndrome: advances in care and future directions.

Central nervous system (CNS) embryonal tumors, commonly found in pediatric patients, represent a heterogeneous mix of lesions with an overall poor (though improving) prognosis. Medulloblastomas are by far the most frequently encountered and most widely studied subtype, though others include atypical teratoid/rhabdoid tumors (AT/RTs), embryonal tumor with multilayered rosettes (ETMRs), and CNS neuroblastomas, FOX-R2 activated. The classification, diagnosis, and treatment of these lesions have evolved drastically over the years as their molecular underpinnings have been elucidated. We describe the most recent 2021 WHO Classification system, discuss current understanding of the genetic basis, and demonstrate current thinking in treatment for these highly complex tumors. Since surgical resection continues to remain a mainstay of treatment, preventing and managing surgical complications, especially cerebellar mutism syndrome (CMS), is paramount. We describe the current theories for the etiology of CMS and two centers' experience in mitigating its risks. As our surgical toolbox continues to evolve along with our understanding of these tumors, we hope future patients can benefit from both improved overall survival and quality of life.

MN1 altered astroblastoma with APC and LRP1B gene mutations: a unique variant in the cervical spine of a pediatric patient.

PURPOSE: Astroblastomas (AB) are high-grade neoplasms which typically occur within the cerebral hemisphere. However, given the rarity of this neoplasm and the number of variants, the relevance of this molecular makeup is unknown. We sought to describe the clinical presentation, treatment, and pathological analysis of a novel MN1 (meningioma 1) cervical spinal cord astroblastoma variant presenting in a pediatric patient. METHODS: A retrospective review of electronic medical records was performed with an emphasis on neuroimaging, perioperative course, and pathological analysis. RESULTS: An 11-month-old male with no significant history presented with two weeks of neck stiffness and cervicalgia. Neurologically, the patient was intact without signs of infection or trauma. Cervical CT was unremarkable. A subsequent MRI demonstrated a heterogeneously enhancing intramedullary lesion extending from the craniocervical junction to T4. The patient was treated with perioperative steroids and underwent C1-C3 laminectomies and C4-T4 laminotomies for tumor resection. Upon completion of the durotomy, an exophytic gray-red tumor was appreciated within the epidural space and gross total resection was achieved (no change on intraoperative neurophysiological monitoring) and confirmed on post-operative imaging. Immunohistochemical analysis was consistent with an astroblastoma with atypical diffuse positivity of CD56, CD99, and nuclear OLIG2. Molecular analysis revealed not only MN1 alterations but also changes in genes encoding APC and LRP1B. Both alterations were not previously documented to be associated with an astroblastoma. CONCLUSION: Our case represents the first report of an infant with an MN1 astroblastoma with APC and LRP1B gene alterations in the cervical spine. Gross total resection paired with a detailed histopathologic analysis is vital for optimizing adjuvant treatment.

Comparison of Clinical and Radiographic Outcomes After Standalone Versus Cage and Plate Constructs for Anterior Cervical Discectomy and Fusion.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) has conventionally been performed using an allograft cage with a plate-and-screw construct. Recently, standalone cages have gained popularity due to theorized decreases in operative time and postoperative dysphagia. Few studies have compared these outcomes. Here, we directly compare the outcomes of plated versus standalone ACDF constructs. METHODS: A single-center retrospective review of patients undergoing ACDF after June 2011 with at least 6 months of follow up was conducted. Clinical outcomes were analyzed and compared between standalone and plated constructs. Multivariate regression analysis of the primary outcome, need for revision surgery, as well as several secondary outcomes, procedure duration, estimated blood loss (EBL), length of hospital stay, disposition, and incidence of dysphagia, hoarseness, or surgical site infection, was completed. RESULTS: A total of 321 patients underwent ACDF and met inclusion-exclusion criteria, with mean follow-up duration of 20 months. Forty-six (14.3%) patients received standalone constructs, while 275 (85.7%) received plated constructs. Fourteen (4.4%) total revisions were necessary, 4 in the standalone group and 10 in the plated group, yielding revision rates of 8.7% and 3.6%, respectively (P = .125). Mean EBL was 98 mL in the standalone group and 63 mL in the plated group (P = .001). Mean procedure duration was 147 minutes in the standalone group and 151 minutes in the plated group (P = .800). Mean hospital stay was 3.6 days in the standalone group and 2.5 days in the plated group (P = .270). There was no significant difference in incidence of dysphagia (P = .700) or hoarseness (P = .700). CONCLUSIONS: Standalone ACDF demonstrates higher, but not statistically significant, revision rates than plate-and-screw constructs, without the hypothesized decreased incidence of dysphagia or hoarseness and without decreased procedure duration or EBL. Surgeons may consider limiting use of these constructs to cases of adjacent segment disease. Larger studies with longer follow up are necessary to make more definitive conclusions. LEVEL OF EVIDENCE: 4. CLINICAL RELEVANCE: This study will help spine surgeons decide between using standalone or cage-and-plate constructs for ACDF.