Experimental Assessment of a 3D-Printed FBG-Based Forceps for Minimally Invasive Surgery: Gripping Tests on Ex Vivo Animal Tissues

One of the main limitations of minimally invasive surgery (MIS) is the restricted sensory feedback available to the surgeon, potentially compromising precision and increasing the risk of tissue damage. To address this issue, research has explored solutions for providing tactile and force (F) feedback. Among these, fused deposition modeling (FDM) has emerged as a promising technique for fabricating bridge-shaped structures that, under transverse loads—such as those generated during tissue gripping—can induce tension in fiber Bragg grating sensors (FBGs), enabling F feedback to the surgeon. Despite the multiple advantages of FBGs (e.g., compact size, immunity to electromagnetic interference) and FDM (e.g., low cost, use of biocompatible materials), the development of 3D-printed FBG-based sensorized forceps for $\mathbf{F}$ feedback remains relatively unexplored in the context of MIS. This study validates a MIS forceps prototype entirely fabricated using the FDM technique, integrating an FBG-based sensing element for real-time $\mathbf{F}$ feedback. The device was tested on ex vivo porcine tissues (i.e., lung, heart, trachea) characterized by different stiffness properties. Experimental results demonstrate that the presence of $\mathbf{F}$ feedback improves grip stability, leading to greater consistency across trials performed on the same porcine tissue. Furthermore, the analysis of the sensing element output distribution revealed greater variations during the gripping of stiffer tissues. These findings suggest that integrating FBGs within FDM-printed structures represents an effective strategy to improve F control in MIS, offering a viable approach to enhancing sensory feedback in MIS procedures.