The 2013 Sixto Obrador Award. A triple-axis topographical model for surgical planning of craniopharyngiomas. Part I: historical review of the topographical diagnosis and classification schemes of craniopharyngiomas

Abstract

This study reviews the historical evolution of pathological, neuroradiological and surgical evidence that influenced the topographical concepts and classification schemes of craniopharyngiomas. An extensive, systematic analysis of the surgical series of craniopharyngiomas reported in the literature was performed (n=145 series, 4,588 tumours) to describe the fundamental anatomical findings guiding the topographical classification schemes used for this tumour throughout history. These findings were compared with topographical relationships reported for well-described operated craniopharyngiomas (n=224 cases) as well as for non-operated cases studied in autopsies (n=201 cases). Two major variables define the topography of a craniopharyngioma: its position relative to the sellar diaphragm and its degree of invasion of the third ventricle floor. Suprasellar lesions displacing the third ventricle floor upwards (pseudointraventricular craniopharyngiomas) are amenable to safe, radical resection and must be differentiated from lesions developing primarily within the third ventricle floor (infundibulo-tuberal or not strictly intraventricular craniopharyngiomas). The latter group typically shows tight, circumferential adhesion to the third ventricle floor and represents approximately 40% of all cases. A triple-axis topographical model for craniopharyngiomas that includes the degree of hypothalamus invasion is useful in planning surgical approach and degree of resection. The group of infundibulo-tuberal craniopharyngiomas associates the highest risk of hypothalamic injury (50%). The endoscopically-assisted extended transsphenoidal approach provides a proper view to assess the topography of the craniopharyngioma and its degree of adherence to the hypothalamus.