Preliminary study of a sensorized system for real-time feedback for arachnoid collapse during neurosurgical training

The transsphenoidal surgery approach is a new minimally invasive procedure used by neurosurgeons to treat pituitary adenomas. One of the most challenging aspects of the surgery is handling the arachnoid membrane when it starts collapsing, as it is a thin and fragile membrane that contains the cerebrospinal fluid (CSF). 3D-printed training models do not provide a system capable of mimicking the arachnoid collapse during surgery. This work reports the results of two tests on a specifically designed system capable of reproducing the arachnoid and the CSF within. The system consists of a jar filled with distilled water and sealed with a food film and a screw cap. In addition, a pressure sensor is inserted into the system to measure the change in pressure generated by an indenter connected to a load cell. The idea is to correlate the indentation force with the pressure variation. Data show a promising result in both tests, with a evident correlation between force and pressure. The first test shows a linear trend, with an R2 = 0.984 for the loading phase and a R2 = 0.999 for the unloading phase. The second test shows a linear trend with R2 = 0.954 from the unloading phase, while as for the loading phase, it has a nonlinear trend for values of applied force less than 1 N, which then tends to a linear trend above this value, with an R2 = 0.996. However, there is a low repeatability when comparing one test with another due to the initial conditions of the food film, residual stresses and deformations once positioned on the top of the jar and closed by the cap, and probable pressure losses in the system.