Utility of minimally invasive endoscopic skull base approaches for the treatment of drug-resistant mesial temporal lobe epilepsy: a review of current techniques and trends.

Mesial temporal lobe epilepsy (mTLE) is an important cause of drug-resistant epilepsy (DRE) in adults and children. Traditionally, the surgical option of choice for mTLE includes a frontotemporal craniotomy and open resection of the anterior temporal cortex and mesial temporal structures. Although this technique is effective and durable, the neuropsychological morbidity resulting from temporal neocortical resections has resulted in the investigation of alternative approaches to resect the mesial temporal structures to achieve seizure freedom while minimizing postoperative cognitive deficits. Outcomes supporting the use of selective temporal resections have resulted in alternative approaches to directly access the mesial temporal structures via endoscopic approaches whose direct trajectory to the epileptogenic zone minimizes retraction, resection, and manipulation of surrounding cortex. The authors reviewed the utility of the endoscopic transmaxillary, endoscopic endonasal, endoscopic transorbital, and endoscopic supracerebellar transtentorial approaches for the treatment of drug-resistant mesial temporal lobe epilepsy. First, a review of the literature demonstrated the anatomical feasibility of each approach, including the limits of exposure provided by each trajectory. Next, clinical data assessing the safety and effectiveness of these techniques in the treatment of DRE were analyzed. An outline of the surgical techniques is provided to highlight the technical nuances of each approach. The direct access to mesial temporal structures and avoidance of lateral temporal manipulation makes endoscopic approaches promising alternatives to traditional methods for the treatment of DRE arising from the temporal pole and mesial temporal lobe. A dearth of literature outlining clinical outcomes, a need for qualified cosurgeons, and a lack of experience with endoscopic approaches remain major barriers to widespread application of the aforementioned techniques. Future studies are warranted to define the utility of these approaches moving forward.