The Evolution of Endoscopic Skull Base Surgery Outcomes: Defining the Edge of the Envelope

Background: Endoscopic skull base surgery is a relatively new approach in the neurosurgical armamentarium and its usefulness is still being explored. As the field has evolved, so too have the results. For this reason, it is important to re-examine the outcomes of surgery for a variety of diseases individually over time to determine the appropriate indications for these approaches. Methods: We performed a systematic review of recent literature (since 2012) of all studies using the endoscopic endonasal approach (EEA) for craniopharyngioma, olfactory groove, planum sphenoidale, tuberculum sellae meningioma, esthesioneuroblastoma, chordoma, and chondrosarcoma and discuss outcomes compared with a transcranial approach (TCA). These results are also compared with a series of reviews of the literature that were performed before 2012 to see how results have evolved over time. Results: For chordomas, craniopharyngioma and planum sphenoidale/tuberculum sellae meningiomas, EEA has shown superior outcomes to TCA for well-selected cases. Olfactory groove meningiomas still have a better outcome when performed using TCA. Esthesioneuroblastoma requires consideration of tumor stage and extent to select the appropriate approach, although with time, more advanced tumors have become approachable with EEA. Chondrosarcoma is a rare lesion that may be resectable by EEA when anatomy is favorable, although its rarity makes comparison difficult. Conclusions: Advances in EEA make it a useful tool that is at times superior to TCA for specific diseases based on recently published literature reporting rates of resection and complications. Ongoing re-evaluation of outcomes is essential to providing the best information to surgeons choosing an approach in each patient.