Design and Fabrication of Soft Magnetic Manipulators for Clinical Applications

While endoscopic approaches offer advantages over open surgeries, they still suffer from numerous limitations. One of the biggest challenges is related to device miniaturization and access to deeper anatomy. The research presented here investigates methods for enhancing endoscopic technologies using Soft Magnetic Manipulators (SMMs), enabling the needed miniaturization through magnetic actuation. We explore a novel technique to mitigate torsional behavior in unstable actuation scenarios through a monolithic double helix reinforcement. Then, we investigate methods for simultaneously actuating two SMMs within a single anatomical and magnetic workspace. The first method entails employing the double helix reinforcement in conjunction with a specific magnetization profile of the SMMs to enable independent actuation of both. The second method involves applying local gradient fields, maintaining homogeneity in mechanical and magnetic designs between the agents. Cross-talk, cross activation and available area for each manipulator were experimentally evaluated for both methods. Clinical applicability of the proposed system was shown in a brain phantom, mimicking laser ablation of a lesion in a pituitary fossa. Evaluation of laser tip position showed the average positional error of 0.13 mm.
Furthermore, the double helix reinforcement is extensively examined in a characterization study. Nine prototypes with varied design parameters are compared to identify the ones that correspond to the most optimal response to unstable actuation cases.