Yoshitaka Nagashima

Chiari malformation type I is a structural anomaly of the posterior fossa characterized by cerebellar tonsillar herniation through the foramen magnum, often associated with disrupted cerebrospinal fluid dynamics and elevated intracranial pressure. Papilledema is a rare ophthalmic manifestation in Chiari malformation type I, typically linked to increased intracranial pressure. Isolated visual symptoms without signs of intracranial pressure in pediatric Chiari malformation type I are particularly rare and poorly understood. We report a rare pediatric case of Chiari malformation type I in a 9-year-old girl presenting solely with bilateral papilledema and visual impairment, without typical symptoms of raised intracranial pressure such as headache. Magnetic resonance imaging revealed cerebellar tonsillar descent and cervical syringomyelia. Due to progressive visual decline and the absence of alternative diagnoses, the patient underwent foramen magnum decompression with C1 laminectomy. Postoperatively, visual acuity significantly improved, although papilledema persisted at 9 months. This case challenges the conventional view that papilledema in Chiari malformation type I is solely caused by elevated intracranial pressure. Alternative mechanisms, such as localized venous congestion, mechanical stress on the optic nerve, or regional cerebrospinal fluid flow disturbances, may contribute to papilledema. Persistent papilledema despite clinical improvement supports the hypothesis of localized rather than global intracranial pressure elevation. Pediatric presentations may differ from adult cases in symptomatology and pathophysiology, requiring careful diagnostic and therapeutic considerations. Surgical decompression may lead to functional visual recovery even if anatomical signs such as papilledema persist. This case underscores the need for further research into atypical presentations and underlying mechanisms of Chiari malformation type I, especially in pediatric populations.

Background Spinopelvic fixation (SPF) is widely used for unstable sacral fractures with spinopelvic dissociation; however, conventional constructs often require complex implant configurations and extensive soft-tissue dissection. We evaluated the feasibility and clinical outcomes of a minimally invasive SPF (MIS-SPF) technique using an inline construct without offset connectors for the treatment of unstable sacral fractures. Methods The study included 5 consecutive patients with nonosteoporotic AO Spine Sacral Injury Classification Type C fractures who underwent MIS-SPF using an inline construct between September 2024 and March 2026. The construct consisted of lumbar pedicle screws connected to cranial iliac screws using bilateral longitudinal rods, whereas the caudal iliac screws were directly connected using a transverse rod. Perioperative variables, clinical outcomes, radiographic bone union, neurological recovery, and complications were retrospectively evaluated. Results The mean operative time was 200.2 ± 87.5 minutes, and the mean estimated blood loss was 154.6 ± 76.9 mL. When limited to the L4–iliac SPF procedures, the mean operative time was 149.0 minutes. Four patients completed at least 12 months of follow-up. All achieved radiographic bony union and regained independent ambulation. The mean Gibbons score improved from 3.3 ± 0.5 preoperatively to 2.0 ± 0.0 at final follow-up. No implant failure, surgical site infection, or revision surgery was observed. Conclusions In this preliminary case series, MIS-SPF using an inline construct without offset connectors was feasible and demonstrated encouraging short-term clinical and radiographic outcomes. Further comparative and biomechanical studies are warranted to clarify its role in the treatment of unstable sacral fractures. Clinical Relevance This technical report describes a simplified minimally invasive SPF technique using an inline construct without offset connectors, which may facilitate surgical procedures while providing stable fixation for unstable sacral fractures. Level of Evidence 4.

This report describes a rare and challenging case of severe lumbar spinal canal stenosis resulting from extensive, concurrent lumbar ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF). A 44-year-old female patient who initially presented with numbness and gait instability due to thoracic spinal cord compression was successfully managed by thoracic decompression and fusion. However, she subsequently developed lower back pain, buttock pain, and numbness along both legs due to severe multilevel lumbar stenosis from L2 to L5. Surgical management involved multilevel posterior laminectomy with careful removal of extensive ossified ligaments. Postoperatively, the patient's symptoms improved, and lumbar alignment was maintained without the need for fusion. This case highlights the surgical complexity of extensive multilevel lumbar ossification and the necessity of comprehensive whole-spine evaluations in managing spinal ligament ossification. Timely surgical intervention is also crucial in preventing permanent neurological deficits.

Objective: Maintaining the occipito-axial (O–C2) angle following occipitocervical fusion is crucial to prevent postoperative complications. Although automated O–C2 measurement has been reported, practical methods that provide rapid results for routine practice remain limited. This study aimed to develop a deep learning model using the YOLO (You Only Look Once) object detection algorithm to automatically identify anatomical landmarks and rapidly calculate the O–C2 angle.Methods: A retrospective analysis was conducted using cervical spine radiographs from 2 independent facilities. The internal dataset comprised 574 lateral cervical radiographs from 271 patients for model development, while the external validation dataset included 100 radiographs from 100 patients. Model performance was evaluated against manual measurements by 3 expert raters.Results: The model demonstrated excellent detection performance, achieving perfect metrics for the hard palate (F1 score: 1.00) and high performance for the occipital bone (F1 score: 0.97), anteroinferior corner of C2 (F1 score: 0.99), and posteroinferior corner of C2 (F1 score: 0.99). For O–C2 angle estimation, the mean absolute error was 2.35° and root mean squared error was 2.98°, with an accuracy of 94.7% for determining the presence or absence of the O–C2 angle (i.e., whether all 4 anatomical landmarks were simultaneously detected). Bland-Altman analysis revealed minimal bias (0.57°; 95% confidence interval, -0.06° to 1.12°) with limits of agreement from -5.19° to 6.33°. Inference time was approximately 0.14 s per image.Conclusion: Our deep learning model enables rapid and accurate O–C2 angle measurement on lateral cervical radiographs, demonstrating performance comparable to expert raters and potential clinical utility.

Background/Objectives: Anti-calcitonin gene-related peptide monoclonal antibodies (CGRP-mAbs) are effective injectable medications for the treatment of migraine. This study aimed to evaluate continuation, resumption, and withdrawal rates of CGRP-mAb treatment under real-world clinical conditions. Methods: Treatment-naïve patients with at least 3 months of follow-up after starting CGRP-mAb treatment were included. The decision to continue, discontinue, or resume CGRP-mAb treatment was made freely by the patients. Headache Impact Test-6 (HIT-6) and the Migraine-Specific Quality of Life Questionnaire (MSQ) were administered before starting treatment and one month after each CGRP-mAb injection. The endpoints were as follows: continuation rates of CGRP-mAb treatment after treatment initiation; resumption rate; withdrawal rate; changes in HIT-6 and MSQ scores; and differences in background factors between the resumption and withdrawal groups. Results: Of the 1162 migraine patients, 146 were included in the analysis. Continuation rates of CGRP-mAb treatment at 3, 6, 9, 12, 18, and 24 months were 93.2%, 80.2%, 68.9%, 58.8%, 55.4%, and 51.7%, respectively. For the patients who discontinued, the resumption rate was 76.8%, and the withdrawal rate was 20.7%. HIT-6 and MSQ scores were significantly decreased at all assessment points compared with before CGRP-mAb treatment. There were no significant differences in factors between the resumption and withdrawal groups. Conclusions: Under real-world clinical conditions in which patients were free to choose their own treatment, the continuation rate of CGRP-mAb treatment 12 months after treatment initiation was 58.8%, and more than half of patients remained on treatment after 24 months. The resumption rate was 76.8% and the withdrawal rate was 20.7%.

Spontaneous intracranial hypotension (SIH) is a condition caused by cerebrospinal fluid (CSF) leakage, leading to low intracranial pressure (ICP), brain sagging, and subdural hematoma (SDH). Management of SIH complicated by SDH presents a clinical challenge: treating CSF leaks is performed by epidural blood patch (EBP), which elevates ICP, while SDH management typically requires hematoma evacuation, producing a reductive effect on ICP. Mismanagement can result in severe complications such as brain herniation or rebound intracranial hypertension. We report two cases of SIH-associated SDH successfully treated with simultaneous burr hole drainage and EBP, guided by continuous ICP monitoring. Both patients presented with significant SDHs and clinical signs of SIH. At the start of the procedure, subdural ICP was relatively low. After administration of autologous blood, ICP rose rapidly to over 30 mm Hg, reaching levels considered dangerously high if left unaddressed. The hematoma was evacuated without delay, and patients had no recurrence or complications. EBP under real-time monitoring facilitated timely intraoperative decisions and tailored responses to dynamic intracranial changes. This approach provides a framework for individualized and safe intervention in complex dual-pathology scenarios.

Spinal ependymomas are common intramedullary tumors that can show dynamic changes in magnetic resonance imaging findings over time. This study aimed to analyze these imaging changes and their implications for perioperative management. The retrospective study included patients diagnosed with World Health Organization grade 2 spinal ependymoma who underwent surgical resection and had at least 2 preoperative magnetic resonance imaging scans. Patients were divided into 2 groups based on the presence or absence of radiographic changes on magnetic resonance imaging. Magnetic resonance imaging analyses included non-contrast T1- and T2-weighted images, as well as gadolinium-enhanced T1-weighted images when available. Key features evaluated included intraparenchymal edema, hemosiderin deposition, syringomyelia, and cyst components. Changes in tumor size and contrast enhancement patterns were documented. Radiographic changes were identified in 4 out of 15 cases (26.7%). All cases with imaging changes exhibited hemosiderin deposition or hemorrhage, significantly higher than in cases without changes (100% vs. 18.2%, p < 0.05). No significant differences were observed in the presence of cystic components, syringomyelia, or edema between the groups. In the group with radiographic changes, the timeframe for these changes in the images ranged from 3 days to several years. Spinal ependymomas can demonstrate dynamic magnetic resonance imaging changes during the preoperative period, including both growth and reduction in tumor size. The presence of hemosiderin deposition or hemorrhage might be associated with these imaging changes. Proper timing of magnetic resonance imaging is crucial for informing surgical planning and optimizing treatment strategies for patients with spinal ependymomas.