Endoscopy in Temporal lobe Glioma and Metastasis resection: Is there a Role?

BACKGROUND: Surgical access to the temporal lobe is complex with many eloquent white fiber tracts, requiring careful pre-operative surgical planning. Many microsurgical approaches to the temporal lobes are described, each with their own disadvantages. The adoption of the endoscope in neurosurgery has increased the options available when treating these difficult access tumors. OBJECTIVES: We present our experience of a novel, minimally-invasive, endoscopic approach to resect temporal lobe tumors. METHODS: All patients undergoing endoscopic temporal lobe tumor resection between 1 December 2011 and 1 December 2017, under a single surgeon, were included. Tumors were resected through a minicraniotomy using a high-definition rigid endoscope with a 0 and 30-degree viewing angle. Bimanual resection was performed using standard microsurgical technique. RESULTS: There were a total of 45 patients (22 males and 23 females) with a mean age of 53 years. There were 23 (51%) glioblastoma multiforme, 11 (24%) metastases, 7 (16%) Astrocytoma, 3 (7%) anaplastic astrocytoma and 1 (2%) WHO grade I glioneuronal tumor. In 82.2% of cases (37/45), >95% resection was achieved with 42.2% (19/45) patients achieving gross total resection. CONCLUSION: The endoscope has a role in temporal lobe intraparenchymal tumor surgery especially in three illustrative scenarios: 1) medial temporal, parahippocampal-gyrus low-grade non-enhancing gliomas, 2) subcortical high-grade glioma and metastases medial to the sagittal stratum and 3) recurrent gliomas with cystic resection cavity. The endoscope offers a safe and a useful adjunct to the surgeons' armamentarium in brain tumor surgery. A minimally invasive approach also reduces surgical morbidity and length of stay.