Tumor Model for Endoscopic Endonasal Microsurgical Simulation: A Step-By-Step Guide
Background: Endoscopic endonasal skull base surgery is a major challenge for residents and non-experienced neurosurgeons; it has a steep learning curve and the pathology is highly variable both in frequency and degree of invasiveness. Different models for endoscopic training have been described, with different advantages and weak points, such as costs, feasibility and availability.
Objective: Describe a stepwise construction of a feasible and economically viable tumor model for endoscopic endonasal surgery simulation in cadaveric specimens.
Methods: Commercial use polyurethane foam was prepared and placed in a 10 ml plastic syringe. The syringe was attached to a 20 cm long catheter. A frontotemporal craniotomy was performed in a human cadaveric head specimen, and the catheter placed in the suprasellar, sellar, anterior cranial base, petroclival and clival regions with endoscopic guidance. The foam was instilled with a flow of 1 ml per minute, thus controlling its shape, involvement and displacement of surrounding structures. The catheter was withdrawn and the specimen stored for 24 hour in a -20°C refrigerated environment. Subsequently, an expanded endoscopic endonasal approach to the anterior skull base, sellar, clival and petroclival regions was performed. The tumor model was dissected with microsurgical techniques, following a four-hand / two-surgeons disposition. The adherence, consistency and shape of the tumor model were assessed and tested by senior endoscopic skull base surgeons.
Results: The characteristics of the foam were suitable for endoscopic microsurgical dissection. The adherence to surrounding structures is enough to demand a careful dissection by the surgeon, without being so excessive that makes it impossible.
Conclusions: As demonstrated, the tumor model presented is an economic viable, simple and feasible way to train residents and non-experienced surgeons in endonasal tumor removal, to improve the steep learning curve of endoscopic skull base surgery.