Introduction: The main limit of neuronavigation is the brain shift-phenomenon. This is responsible for a progressive loss of accuracy of neuronavigation during brain tumor surgery. We propose a new method to correct brain shift and update neuronavigation based on the combination of intraoperative Ultrasound (i-US) and intraoperative Computed Tomography (i-CT).
Methods: 8 patients underwent microsurgical resection of brain tumor (4 metastases, 4 gliomas). Navigated ultrasound system and portable small bore CT scanner were used to update neuronavigation data and to correct brain shift. Navigated B-mode ultrasound were used after dural opening to identify the lesion and to correct the brain shift due to CSF leak. After tumor resection, post-contrast iCT was performed in order to detect small tumor remnants and correct brain shift. A final i-US check was performed to verify the completeness of resection.
Results: Adjunctive resection was performed in 3 of 8 cases after i-CT. The progressive shifting of the brain was documented and recorded during all the procedures. Mean brain shift along the main vector was 15 mms comparing i-CT with pre-operative imaging. Final i-US control was useful to verify the completeness of remnants resection.
Conclusions: The combination of different intraoperative imaging modalities may increase the safety and the extension of resection of brain malignancies. Our preliminary experience is promising, but further studies are requested to validate this intraoperative imaging protocol.
Patient Care: The proposed protocol may increase the accuracy and safety of brain tumor resection.
Learning Objectives: By the conclusion of this session, participants should be able to:
- know the technical feasibility of intraoperative Ultrasound and Computed tomography
- discuss the indication for intraoperative imaging
- evaluate the importance of brain shift phenomenon as weakness of standard neuronavigation is corrective intraoperative imaging modalities are not used