Modeling Nasal Septal Flap Repair of an Anterior Skull Base Defect: A Pilot Simulation Study

Introduction: Mastering skills in endoscopic skull base surgery presents a daunting task for trainees. Conventional training relies heavily on hands-on patient experiences, the constraints of surgical volume, resident exposure, and patient safety. This limits the range and frequency of surgical techniques that can be practiced. Simulation-Based Medical Education (SBME) provides a controlled environment where residents can refine surgical techniques without jeopardizing patient safety. Here, we present a SBME simulation study utilizing 3D printed sinus models to rehearse nasoseptal flap repair of an anterior skull base defect.

Methods: Thirteen otolaryngology residents participated in simulated harvesting of a nasoseptal flap to close a standardized anterior skull base defect on a 3D printed model. All 3D models were created with multiple polymeric materials to simulate true mucosa, bone and sinus anatomy. All models had a prior ethmoidectomy followed by creation of a uniform 5-mm defect located in the cribriform plate to standardize the protocol. Participants first performed a timed unilateral nasal septal flap harvest and skull base defect repair without instruction. A leak test was then performed using 10 mL of saline placed above the defect to simulate cerebrospinal fluid. Watertight closure lasting greater than 30 seconds was considered successful repair, closure lasting 11 to 30 seconds was considered partial repair, and closure lasting < 10 seconds was considered inadequate repair. Participants were given immediate feedback on flap placement followed by detailed verbal and written instructions on surgical technique. An identical defect was then created on the contralateral skull base and participants repeated the task. Outcomes of interest included resident confidence level, time to harvest, time to insetting, pedicle survival, adequacy of repair, and resident-rated learning experience.

Results: The average time for procedure completion before feedback was 22.1 minutes (SD = 7.3). This decreased to 17.6 minutes (SD = 5.4) following feedback and instruction for an average improvement of 4.5 minutes (CI: 0.11–8.82; p = 0.045). Prior to completing the training simulation, average confidence level to complete the procedure was 4.38 (SD = 2.14) (on a scale from 1 to 10). Confidence levels improved to 7.46 (SD = 1.39) on average with a mean improvement of 3.08 (CI: 1.99–4.17; p < 0.01). The flap pedicle was avulsed in 6/13 septal flaps (46%) on the first attempt, but in only 1/13 flaps (7.6%) following feedback (p = 0.025). There was successful coverage of the defect in 1/13 defects (7.6%) on the primary side and in 7/13 defects (54%) following feedback (p = 0.034). Participants rated the applicability of this simulation highly and reported an average satisfaction score of 9.15 out of 10 for the overall learning experience.

Conclusion: SBME for endoscopic repair of anterior skull base defects allows resident surgeons to practice an important and complicated procedure in a safe and controlled manner. Participants in this study significantly improved in confidence, speed, and procedural adequacy with this simulated practice ([Figs. 1] and [2]).

Fig. 1

Fig. 2

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Artikel online veröffentlicht:
05. Februar 2024