Background/Objectives: Anterior cervical discectomy and fusion (ACDF) is a common procedure for treating cervical spondylotic myelopathy. Limited research exists on the predictors of subsidence following ACDF. Subsidence can compromise surgical outcomes, alter alignment, and predispose patients to further complications, making it essential to prevent and understand it. This study aims to identify key risk factors for clinically significant subsidence and evaluate its impact on cervical alignment parameters in a large, diverse patient population. Methods: We conducted a retrospective review of patients who underwent ACDF between 2013 and 2022 at a single institution. Subsidence was calculated as the mean change in anterior and posterior disc height, with clinically significant subsidence being defined as three millimeters or more. Univariate analysis was followed by regression modeling to identify subsidence predictors and analyze patterns. Subgroup analyses stratified patients by implant type, number of levels fused, and cage material. Results: A total of 96 patients with 141 levels of ACDF met the inclusion criteria. Patients with significant subsidence were younger on average (52.44 vs. 55.94 years; p = 0.074). Those with less postoperative lordosis were more likely to experience significant subsidence (79.5% vs. 90.2%; p = 0.088). Patients with significant subsidence were more likely to have standalone implants (38.5% vs. 16.7%; p < 0.01), taller cages (6.62 mm vs. 6.18 mm; p < 0.05), and greater loss of segmental lordosis (7.33 degrees vs. 3.31 degrees; p < 0.01). Multivariate analysis confirmed that standalone implants were a significant independent predictor of subsidence (OR 2.679; p < 0.05), and greater subsidence was positively associated with loss of segmental lordosis (OR 1.089; p < 0.01). Subgroup analysis revealed that multi-level procedures had a higher incidence of subsidence (35.7% vs. 28.1%; p = 0.156), and PEEK cages demonstrated similar subsidence rates compared to titanium constructs (28.1% vs. 29.4%; p = 0.897). Conclusions: Standalone implants are the strongest independent predictor of significant subsidence, and those that experience subsidence also show greater loss of segmental lordosis, although not overall lordosis. These findings have implications for surgical planning, particularly in patients with borderline bone quality or requiring multi-level fusions. The results support the use of plated constructs in high-risk patients and emphasize the importance of individualized surgical planning based on patient-specific factors. Further research is needed to explore these findings and determine how they can be applied to improve ACDF outcomes.

Relapsed medulloblastoma (MB) remains a significant cause of pediatric cancer mortality, accounting for approximately 10% of all childhood cancer deaths. Despite advances in molecular characterization and treatment of primary MB, no standardized protocol currently exists for managing recurrence. This case highlights a novel approach to treating relapsed MB and aims to contribute to the evolving understanding of optimal strategies in this setting. The authors describe the case of a pediatric patient with relapsed MB, characterized as group 4 MB, managed with a personalized treatment approach involving repeat craniospinal irradiation, chemotherapy, and bone marrow transplant. In parallel, they review current literature and ongoing clinical trials to contextualize this strategy within the broader landscape of relapsed MB management. The case underscores the heterogeneity in treatment approaches and the lack of consensus regarding best practices. At the time of this report, the patient is approximately 6 months post–bone marrow transplant and continues to be monitored for signs of disease recurrence. This case illustrates the importance of an individualized, multidisciplinary approach to relapsed MB, accounting for prior therapies, tumor biology, and patient goals. Ongoing research and collaboration are essential to establishing more effective, evidence-based standards of care for this challenging diagnosis. https://thejns.org/doi/10.3171/CASE25612

BACKGROUND: Ependymomas are one of the most common pediatric brain tumors. Cerebellopontine angle ependymomas (CPAEs) are a subset of ependymomas that pose unique surgical challenges due to their location and relationship to surrounding neurovasculature, and they are poorly documented in the current literature. This report discusses the unique tenets of these lesions and their implications for successful management. An illustrative case is presented. OBSERVATIONS: A 15-month-old male was found to have a 2021 classification WHO grade 2 ependymoma extending from the fourth ventricle into the cerebellopontine angle. The mass encased cranial nerves V, VII, VIII, IX, X, and XII and both vertebral arteries, and exerted mass effect on the brainstem. The patient underwent staged resections, and gross-total resection (GTR) was achieved. Post-GTR, adjuvant proton therapy was initiated. Postoperative cranial nerve deficits showed partial to full recovery at the 1-year follow-up. Imaging has shown no residual tumor or tumor recurrence. LESSONS: This experience highlights the success of multiple staged resections to maximize resection while preserving as much neurological functional as possible, but many strategies may be used on a case-by-case basis. This case contributes insight to a poorly documented subset of pediatric ependymomas, reinforcing the need for broader reporting of CPAE to guide future management. https://thejns.org/doi/10.3171/CASE25687

BACKGROUND: Pial arteriovenous fistulas (pAVFs) are rare vascular abnormalities in the subpial space, characterized by high-flow connections between pial arteries and draining veins, without an intervening nidus. This case report describes a left parietal pAVF feeding from the angular branch (M4) of the left middle cerebral artery, which presented as an acute subdural hematoma (SDH). OBSERVATIONS: The authors present the case of a 68-year-old neurologically intact male with 1-week history of progressive holocranial headache. Initial noncontrast CT imaging of the head revealed a left-sided SDH. Subsequent CTA confirmed the SDH with a spot sign in the posterior part of the SDH. Digital subtraction angiography identified a left parietal pAVF with an associated saccular aneurysm. The patient underwent successful microsurgical ligation and hematoma evacuation, with no residual fistula or vascular abnormality on follow-up angiography. LESSONS: This case highlights the importance of a lower threshold for advanced imaging in acute SDH with no known predisposing factors. It also focuses on the complexity of managing pAVFs with associated aneurysms, along with the importance of individualized treatment strategies integrating advanced imaging and microsurgical techniques. https://thejns.org/doi/10.3171/CASE25605

BACKGROUND: Relapsed medulloblastoma (MB) remains a significant cause of pediatric cancer mortality, accounting for approximately 10% of all childhood cancer deaths. Despite advances in molecular characterization and treatment of primary MB, no standardized protocol currently exists for managing recurrence. This case highlights a novel approach to treating relapsed MB and aims to contribute to the evolving understanding of optimal strategies in this setting. OBSERVATIONS: The authors describe the case of a pediatric patient with relapsed MB, characterized as group 4 MB , managed with a personalized treatment approach involving repeat craniospinal irradiation, chemotherapy, and bone marrow transplant. In parallel, they review current literature and ongoing clinical trials to contextualize this strategy within the broader landscape of relapsed MB management. The case underscores the heterogeneity in treatment approaches and the lack of consensus regarding best practices. At the time of this report, the patient is approximately 6 months post–bone marrow transplant and continues to be monitored for signs of disease recurrence. LESSONS: This case illustrates the importance of an individualized, multidisciplinary approach to relapsed MB, accounting for prior therapies, tumor biology, and patient goals. Ongoing research and collaboration are essential to establishing more effective, evidence-based standards of care for this challenging diagnosis. https://thejns.org/doi/10.3171/CASE25612