Preliminary Study on a 3D Printed Sensorized Probe to Characterize Pituitary Adenoma Hardness

Endoscopic endonasal transsphenoidal surgery approach, is a new surgical technique used by otolaryngologists and neurosurgeons to resect pituitary adenoma (PA). The most challenging aspect is related to the fact that the strategy of the resection changes according to the hardness of PAs, which is mostly soft, but it can also be harder (fibrous adenoma). This work proposes a first attempt to develop an alternative and innovative sensorized probe capable to discern the different hardness of soft materials. The proposed solution can be implemented in training models in order to give feedback to the users. The probe was developed thanks to additive manufacturing Fused Filament Fabrication (FFF) technology. Inside the probe there is a magneto resistive sensor and a magnet that is glued on the tip in order to measure the variation of the magnetic field linked to the movement of the magnet. After a preliminary electrically characterization of the probe, tests were conducted with three different silicones with slightly different Shore A attested hardness in order to verify if the probe is able to discern the materials. The first results show a high repeatability with a mean variation < 1%. Future work will be conducted with ex-vivo samples of pituitary adenomas in order to characterize their hardness and to classify the different types of PAs with a hardness parameter, and also to find the best material to mimic the consistency for training models.