Unraveling the Efficiency of Non-Navigated 2D Intraoperative Ultrasound in Glioma Surgery: Challenging the Demand for Increased Technological Sophistication in Intraoperative Imaging

Background: In an era characterized by rapid progression in neurosurgical technologies, traditional tools such as the non-navigated two-dimensional intraoperative ultrasound (nn-2D-IOUS) risk being overshadowed. Against this backdrop, this study endeavors to provide a comprehensive and rigorous assessment of the clinical efficacy and surgical relevance of nn-2D-IOUS, specifically in the context of glioma resections. Methods: This retrospective study undertaken at a single center evaluated 99 consecutive, non-selected patients diagnosed with both high-grade and low-grade gliomas. The primary objective was to assess the proficiency of nn-2D-IOUS in generating satisfactory image quality, identifying residual tumor tissue, and its influence on the extent of resection. To validate these results, early postoperative MRI data served as the reference standard. Results: The nn-2D-IOUS exhibited a high level of effectiveness, successfully generating good quality images in 79% of the cases evaluated. With a sensitivity rate of 68% and a perfect specificity of 100%, nn-2D-IOUS unequivocally demonstrated its utility in intraoperative tumor detection. Notably, in cases where total tumor removal was the surgical objective, a resection exceeding 95% of the initial tumor volume was achieved in 86% of patients. Additionally, in cases where residual tumor was not detected by nn-2D-IOUS, the mean volume of undetected tumor tissue was remarkably minimal, averaging at 0.29 cm3. Conclusion: Our study provides compelling evidence supporting the invaluable role and efficacy of nn-2D-IOUS in glioma surgery. The results underscore the potential of harnessing traditional, cost-effective technologies such as nn-2D-IOUS to achieve enhanced surgical outcomes, even in the face of more advanced alternatives. These insights carry significant implications, particularly for resource-constrained settings, emphasizing the importance of optimizing the use of existing tools to improve patient care in a practical and efficient manner. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was partially funded by a grant awarded by the "Instituto Carlos III, Proyectos I-D-i, Accion Estrategica en Salud 2022". Reference PI22/01680. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study received approval from the Institutional Review Board of the Rio Hortega University Hospital and the Ethics Committee for Drug Research (CEIm) of the West Valladolid Health Area (Ref. 21-PI085). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes A portion of the MRI scans used in this study will be made publicly available through The Cancer Imaging Archive at https://www.cancerimagingarchive.net/