3D printed training model with sensorized arachnoid for endoscopic transsphenoidal surgery: development and initial validation

<h2>Abstract</h2><h3>Background</h3> Endoscopic transsphenoidal surgery is a relatively novel technique with a long learning curve: it is used to resect tumors that grow in the sella, which is located at the center of the skull base, immediately below the optic nerves and brain that are wrapped by the arachnoid, containing the cerebrospinal fluid (CSF). One of the challenging aspects of this surgery is to remove the tumor while not damaging the arachnoid to avoid the potentially life-threatening complication of post-operative CSF leak. <h3>Objective</h3> This work presents the development of a new 3D-printed CT-based training model with a sensorized tank capable of reproducing the descent in the sella of the suprasellar arachnoid pushed by the cerebrospinal fluid (CSF) during removal of a sellar tumor with endoscopic transsphenoidal surgery. The system provides real-time feedback about the force exerted by the operating surgeon through the pressure sensor integrated into the tank. <h3>Development</h3> The model and the tank were fabricated using additive manufacturing technologies and silicone mold casting to reproduce soft tissues like skin and mucosa. The arachnoid membrane and the CSF were mimicked with a polymeric film and distilled water, while the pituitary adenoma was mimicked with boiled egg white. <h3>Validation</h3> The correlation between the pressure of the CSF and the exerted force was investigated in characterization tests. Eleven experienced surgeons were asked to simulate the resection of a pituitary adenoma using the model. At the end of the experience, a survey was conducted amongst surgeons to evaluate the model and its usefulness as a tool for training. <h3>Conclusions</h3> The collected data allowed the definition of the force threshold values for the risk of CSF leak. The maximum force exerted by surgeons is 0.526 N. Surgeons considered the arachnoid well simulated and thought that the model could be a helpful training tool for endoscopic transsphenoidal surgery.