10261- STMO-22 RADICAL SURGICAL RESECTION FOR THALAMIC TUMORS USING OCCIPITAL TRANSTENTORIAL APPROACH WITH INTRAOPERATIVE MRI

Abstract BACKGROUND Thalamic tumor has been one of the most challenging part to operate in neurosurgery due to its risks associated with surgical procedures. Occipital transtentorial approach (OTA) is adaptable not only pineal lesion but also thalamic tumor located at pulvinar part. Intraoperative MRI (iMRI) has proven to be highly useful in these procedures, providing real-time imaging that enhances the precision of tumor resection and minimizes the risk of damage to surrounding critical structures. OBJECTIVE To examine our surgical outcome and usefulness of OTA for thalamic gliomas. We present a retrospective review of our surgical experience with 4 patients presenting symptomatic thalamic gliomas. METHODS OTA was used by prone position with an ipsilateral entry. Following tent incision and dissecting arachnoid membranes around deep vein complex, resection of tumor was performed with making cleavage between tumor and normal brain. Neuronavigation and transcranial motor evoked potentials and intraoperative magnetic resonance imaging (iMRI) were used in all cases. RESULTS Four patients with intrinsic gliomas located at the thalamus and midbrain were operated on. One case with midbrain infiltration resulted in subtotal resection, while total resection was achieved in the remaining three cases. Pathological diagnoses are diffuse astrocytoma, pilocytic astrocytoma, pilomyxoid astrocytoma, and anaplastic pilocytic astrocytoma. Postoperative radiochemotherapy was added in one case of anaplastic pilocytic astrocytoma, respectively. The average follow-up period was 54.9 months, during which all cases maintained independent ADL without tumor recurrence. CONCLUSION OTA for thalamic gliomas who has main mass located at pulvinar part is a safe and reliable approach with the application of high resolution iMRI.