Endoscopic Skull Base Routes to the Hippocampus in Children with Pharmacoresistant Epilepsy: CT/MRI Morphometric Evaluation of the Maxillary Sinus

Introduction: Amygdalohippocampectomy remains a key option for epilepsy treatment in children, yet the choice of surgical corridor may be limited by age-related anatomical development. Transmaxillary and endoscopic endonasal approaches offer minimally invasive access to the hippocampus, but the impact of the size and pneumatization of the pediatric maxillary sinus on their feasibility is unknown. This study aimed to define age-based eligibility for these approaches by analyzing maxillary sinus development on pediatric CT and MRI. Methods: A retrospective radiological morphometric study was performed on 12 pediatric patients and 1 adult patient (ages 3–19 years) who had undergone transcranial epilepsy surgery with available preoperative CT and/or MRI scans. Bilateral maxillary sinus dimensions—including height, width, and anteroposterior length—were measured using multiplanar reconstruction in axial, coronal, and sagittal planes. Additional parameters, such as maxillary sinus operative aperture sizes and maxilla–skull base relationships, were recorded. Age at the time of surgery was correlated with morphometric parameters to identify developmental thresholds for potential endoscopic endonasal and transmaxillary access to the hippocampus. Results: Twenty-six sides were analyzed. Maxillary sinus dimensions demonstrated progressive, age-dependent increases. In early childhood, the maxillary sinus and its aperture typically exhibited a slit-shaped configuration; with increasing age, both evolved toward a quadrangular shape. Based on this morphology, we deemed slit-shaped sinuses not feasible for endonasal/transmaxillary surgery, whereas quadrangular sinuses provided feasible working corridors. Dimensions for children