Introduction: The role of transoral robotic surgery (TORS) in the skull base emerges and represents the natural progression toward miniinvasive resections in confined spaces. The accessibility of the sella via TORS has been recently described on fresh human cadavers. An anatomic study is mandatory to know if this approach would be feasible in the majority of patients regardless of their oral morphological features. Methods: Based on the 30 skull base CT scans obtained from patients who were asked to open their mouth as large as they can, we measured specific dimensions of the oral cavity and the skull base, such as length of the palate, mouth opening, and distance from the sella to the palate. All data were acquired on a sagittal midline plan and on a 25-degreerotation plan, which simulated the axis of the robotic instruments. We studied possible predictive factors of sellar accessibility and tried to bring objective data for surgical feasibility. We also proposed an angle α to study the working angle at the skull base. Results: We observed that the maximal mouth opening was a good predictive factor of sellar accessibility by TORS (p < 0.05). The mouth aperture threshold value for a good sensitivity, over 80%, was comparable to the mean value of mouth opening in our series38.9 and 39.4 mm, respectively. Conclusion: From these anatomical features and previous cadaveric dissections, we assume that TORS may be feasible on a majority of patients to remove pituitary adenomas.