The Minimally Invasive Supraorbital Subfrontal Key-Hole Approach for Surgical Treatment of Temporomesial Lesions of the Dominant Hemisphere

Introduction: Surgery in the temporomesial region is generally performed using a subtemporal, transtemporal, or pterional-transsylvian approach. However, these approaches may lead to approach-related trauma of the temporal lobe and frontotemporal operculum with subsequent postoperative neurological deficits. latrogenic traumatisation is especially significant if surgery is performed in the dominant hemisphere. Methods: During a five-year period between January 2003 and December 2007, we have approached the temporomesial region in 21 cases via the supraorbital approach. In 15 cases, the lesion was located within the dominant hemisphere, all lesions had space-occupying effects. In all cases, meticulous approach planning was performed, demonstrating a close proximity of the lesion to the pial surface on the upper anterior mesial aspect of the temporal lobe. An extension within the parahippocampal gyrus or with deep temporobasal tumor growth below the sphenoid wing were considered as exclusion criteria for using the supraorbital approach. Results: in all cases surgery was performed without intraoperative complications. Pathological investigation showed 7 low-grade astrocytomas,4 high-grade astrocytomas, 2 gangliogliomas and 2 cavernomas. Early postoperative MRI scans confirmed a complete removal of the lesion in 14 cases. In one case of a subtotal resection, the residual tumor was removed through a posterior subtemporal approach. The postoperative neurological examination was unchanged in 14 cases. In one case a transient hemiparesis was observed. In patients with dominant-sided lesions no speech or mental deficits were present. Conclusion: In selected cases, the minimally invasive supraorbital craniotomy offers excellent surgical efficiency in the temporomesial region with no approach-related morbidity compared to a standard transtemporal or pterional-transsylvian approach.