Development of a Physical Simulator Model for Developing and Evaluating Endoscopic Endonasal Surgical Skills

Introduction: Endoscopic endonasal surgical approaches are becoming an important option in skull base surgery, but require the development of a unique skill set in the context of a team approach. There is a need for developing and evaluating endoscopic endonasal surgical skills outside of the operating room for training purposes and for proficiency assessment as has been done in other surgical disciplines. In this study, we test the ability of five simulated surgical tasks to discriminate between surgeons based on skill level and also investigate surgeon perceptions of workload and validity.

Methods: Five tasks were developed by endoscopic skull base faculty to replicate basic surgical maneuvers performed in endoscopic endonasal surgery. These tasks, which were based in part on tasks used in a successful simulator for general surgery training, were tested by neurosurgeons and otolaryngologists of varying skill levels at two skull base workshops (NASBS workshop and Spetzler Rhoton course). The tasks included one-handed tasks (peg transfer and spiral tracing) and two-handed tasks (object slide, peg transfer, precision cutting). A scoring system which accounted for timeliness and accuracy was developed for each task. Exit surveys which included a modified NASA Task Load Index survey were conducted. Univariate GLM models were conducted to determine the discriminative ability of simulation tasks and survey results.

Results: Fifty-two surgeons participated in the initial validation of the tasks. Scoring on the cutting task was suspended after eight participants because it was judged to be too difficult. The remaining four tasks were completed by all participants. One-handed peg transfer (p = 0.001), spiral drawing (p = 0.047), and two-handed peg transfer (p = 0.059), and total score (p = .002) were able to discriminate between experts and novices, whereas object sliding did not (p = 0.16). Experts rated themselves as successful in completing simulation tasks (100%), indicated practice would be beneficial to their surgical skills (92%), and noted that the tasks replicated skull based maneuvers well (77%). Less experienced surgeons felt the tasks would be more beneficial than more experienced surgeons.

Conclusion: This study describes the development of three physical simulator tasks that were able to discriminate endoscopic surgeons by skill level. The final construct, which will include these tasks, could be used to develop surgical skills and also set proficiency benchmarks as has been done in other surgical specialties.