A Sensorized Forceps Combining FBG Technology and FDM Manufacturing for Enhanced Force Feedback in Minimally Invasive Surgery

Despite the growing adoption of minimally invasive surgery (MIS), the absence of effective sensory feedback for surgeons during tissue manipulation, particularly regarding the applied gripping force (F), remains a major limitation, increasing the risk of unintentional tissue damage. This study presents the development of a sensorized forceps that combines the advantages of fiber Bragg grating (FBG) sensors (e.g., compact size and excellent metrological performance) and Fused Deposition Modeling (FDM) (e.g., rapid prototyping and the use of different materials adapted to specific functions) for enhanced F feedback in MIS surgery. A sensing element was developed in 3D-printed thermoplastic polyurethane, hosting an array of three FBGs suspended within a bridge-shaped structure to convert axial strain, generated by transverse loading during tissue gripping, into a measurable estimation of gripping F. Additionally, a fourth FBG was encapsulated in a silicone matrix and placed in a strain-free zone of the lower jaw to compensate temperature variations (ΔT). The MIS forceps prototype itself was entirely fabricated via FDM using polylactic acid. Metrological characterization revealed F sensitivities of 0.13 nm/N, 0.15 nm/N, and 0.21 nm/N for the three FBGs of the array in the 0 N – 2 N range, and a T sensitivity of 0.015 nm/°C for the sensor used for T compensation. Finally, preliminary tests on ex-vivo porcine organs demonstrated that the proposed system enhances gripping stability in the presence of real-time F feedback, confirming its potential for improving intraoperative F awareness in MIS procedures.