Supplementary Material for: Combined transtemporal and high parietal approach for large trigonal intraventricular tumor: A Case Report

Introduction Surgical removal of trigonal intraventricular tumors presents significant challenges. These tumors are primarily supplied by branches of the choroidal artery group arising from the inferior side. To access the vascular pedicles, the shortest and most direct surgical corridor to the trigone is generally preferred, making the transcortical transparietal approach a common choice. However, this approach carries a high risk of damaging critical subcortical white matter tracts. Injury to these tracts can result in language deficits (on the left side), spatial neglect syndrome (on the right side), as well as sensory disturbances and visual field deficits. To minimize disruption to these white matter tracts, the high parietal approach is often recommended. However, this technique presents its own challenges, particularly in achieving early control of arterial feeders, which becomes even more critical in larger trigonal tumors. Case Presentation We present the case of a 13-year-old boy with a large trigonal intraventricular tumor. Given his lack of significant symptoms and his young age, our surgical strategy focused on maximizing the preservation of his neurological function. We developed a novel combined transtemporal and high parietal approach. The small transtemporal approach allows early devascularization, followed by the high parietal approach, which facilitates tumor resection while preserving the vital white matter tracts along the lateral wall of the trigone. Conclusion We propose a novel combined technique that offers a balance between optimal tumor resection and functional preservation, particularly in cases of large and hypervascularized trigonal tumors.