Expanded endonasal approach, a fully endoscopic transnasal approach for the resection of midline suprasellar craniopharyngiomas: a new classification based on the infundibulum

Craniopharyngiomas are notoriously difficult to treat. Surgeons must weigh the risks of aggressive resection against the long-term challenges of recurrence. Because of their parasellar location, often extending well beyond the sella, these tumors challenge vision and pituitary and hypothalamic function. New techniques are needed to improve outcomes in patients with these tumors while decreasing treatment morbidity. An endoscopic expanded endonasal approach (EEA) is one such technique that warrants understanding and evaluation. The authors explain the techniques and approach used for the endoscopic endonasal resection of suprasellar craniopharyngiomas and introduce a tumor classification scheme.The techniques and approach used for the endoscopic, endonasal resection of suprasellar craniopharyngiomas is explained, including the introduction of a tumor classification scheme. This scheme is helpful for understanding both the appropriate expanded approach as well as relevant involved anatomy.The classification scheme divides tumors according to their suprasellar extension: Type I is preinfundibular; Type II is transinfundibular (extending into the stalk); Type III is retroinfundibular, extending behind the gland and stalk, and has 2 subdivisions (IIIa, extending into the third ventricle; and IIIb, extending into the interpeduncular cistern); and Type IV is isolated to the third ventricle and/or optic recess and is not accessible via an endonasal approach.The endoscopic EEA requires a thorough understanding of both sinus and skull base anatomy. Moreover, in its application for craniopharyngiomas, an understanding of tumor growth and extension with respect to the optic chiasm and infundibulum is critical to safely approach the lesion via an endonasal route.