ObjectivePrecise endoscopic skills are critical for endoscopic endonasal surgery (EES) to ensure patient safety, as well as to succeed as a surgeon. Among these skills, basic skills such as hand-eye coordination and bimanual dexterity are the most important skills for novice surgeons. However, there is no proficiency-based training for the basic skills in EES. In this study, we aimed to develop a proficiency-based training curriculum for beginners in EES using tractable tasks and to assess the curriculum's validity and educational benefits. MethodsTraining tasks for basic surgical skills of EES were created by experts, using a low-cost and simple simulator. Subsequently, a proficiency-based training curriculum was developed through a preliminary study. The face and content validity of the curriculum was evaluated by expert surgeons. The construct validity was confirmed by comparing the scores of the medical students with those of the experts. In addition, the educational benefits of the curriculum were assessed by comparing the scores of the medical students before and after the implementation of the curriculum. ResultsA proficiency-based training curriculum using six tractable tasks was developed in the preliminary study. Replication of real surgical situation, camera navigation, and instrument operability under endoscopy were all highly appreciated (4.6, 4.6, and 4.8 out of 5 points, respectively), which indicates face validity. The content validity of the curriculum was demonstrated by the results of the questionnaire (4.4 out of 5 points). The curriculum was implemented by 12 medical students. The initial student scores were significantly lower than the expert scores (mean score: 61.9 vs. 100.0, p < 0.001), and each coefficient of variation of the student scores was higher than that of the expert scores (p < 0.01), supporting the construct validity of the curriculum. The mean student composite scores were statistically improved after the training (61.9 vs. 93.3, p < 0.0001). In addition, improvement of five other medical students’ EES skills through this training curriculum was confirmed in cadaver dissection (1.7 vs. 3.7, p < 0.0001). ConclusionThe validity of the proficiency-based training curriculum developed through the preliminary study was established based on the questionnaire of experts and the difference between student and expert scores. In addition, the educational benefits were demonstrated by the students’ learning curves. The low-cost and simple simulator seems appropriate as an entry model for beginners in EES, and this curriculum can provide rapid intervention and objective assessment of basic skills in EES.