gms | German Medical Science

Objective: In surgery of lateralized TSMs, the contralateral subfrontal approach reduces manipulation of the involved optic nerve and directly visualizes the inferomedial aspect of the compromised optic nerve which could result in improvement of post-operative visual outcomes. However, the possible risk of insult to the approach-side eye is an important issue that cannot be ignored and it is important to select the appropriate patients for this approach. In this study, we analyzed the surgical outcome with attention to visual function and propose the surgical indication of contralateral subfrontal approach. We also discuss the technical aspect for reducing the approach-related visual deterioration.

Method: Between 1999 and 2015, 101 patients with TSMs underwent surgical resection in our institute. Among them, 40 patients underwent via ipsilateral subfrontal approach, 4 patients underwent via bifrontal interhemispheric approach, and one patient underwent via endonasal transtuberculum approach. Remained 55 patients underwent surgical resection via contralateral subfrontal approach since 2005. Contralateral approach access the tumor from the opposite side of amblyopia. Using this technique, the tumor was separated from the non-compromised optic nerve with only internal debulking. The tumor was dissected from optic nerve without manipulation of compromised optic nerve under the direct view of inferomedial aspect of the optic nerve. The tumor extended into the optic canal could be removed easily via dural unroofing of the medial wall of the optic canal. Variable factors including tumor size, consistency of tumor, extent of resection, direction of approach and preoperative visual function of approach-side eye were analyzed with attention to the post-operative visual outcome on approach-side eye.

Results: The preservation of visual function (improve or stable) on affected eye was achieved 96.4% after surgery. However, the deterioration of approach-side eye was developed on 6 patients (10.9%). Interestingly, surgical approach-related visual deterioration was developed more frequently in cases of right-sided approach than left-sided approach. Visual deterioration of approach-side eye also occurred more frequently in patients with bilateral visual deficit than patients with unilateral one.

Conclusions: Based on our surgical experiences, eccentric located tuberculum sellae meningioma with unilateral visual disturbance is absolute indication for contralateral subfrontal approach. Midline located tuberculum sellae meningioma with asymmetric bilateral visual disturbance are thought to be relative indication for unilateral approach. Otherwise, in the case of patient with severe bilateral visual deficits, midline approach can provide a higher chance to improve visual outcome of both eyes than unilateral subfrontal approach.