Shape Deposition Manufacturing of a “Smart”, Atraumatic, Deployable Surgical Grasper for Robotic-Assisted Pancreas Operations

Ammara A Watkins1, Joshua Gafford2, Ye Ding2, Andrew Harris2, Terrence McKenna2, Panagiotis Polygerinos2, Donald Holland3, Conor Walsh4, Arthur J Moser1. 1Beth Israel Deaconess Medical Center, 2Harvard University, 3Trinity College Dublin, Ireland, 4Wyss Institute for Biologically-Inspired Engineering

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Objective: Current grasping devices for minimally-invasive surgery employ outdated “pinching” designs which are traumatic to soft tissue. We developed a multifunctional atraumatic grasper with “smart” on-board pressure sensors for manipulation and retraction of soft pancreas deployable through a 15 mm laparoscopic trocar.

Description of technology and method of its use or application: We created an innovative surgical grasper to manipulate the pancreas and liver during minimally invasive surgery. The design consists of (1) three multi-jointed cable-actuated fingers, (2) a “quick-release” handle, and (3) a “Smart” pressure sensing system with visual force- feedback. The grasper features a three-finger morphology with proportionally decreasing joint stiffness. The grasper can be closed with either laparoscopic or robotic forceps, and the mechanism features a ratchet system to maintain tension. The grasper has a “quick release” mechanism to allow rapid disengagement as a failsafe. The distal aspect of each finger has a pressure sensor that relays color-coded force information to the surgeon, and the pre-defined pressure for the transition of green (go) to red (stop) can be customized. The grasper is deployed through a 15 mm port and can be used in laparoscopic or robotic-assisted surgery. The fingers were fabricated from urethane-based polymers by means of shape deposition manufacturing, and the quick-release handle was fabricated from bronze-infused stainless steel by means of direct metal laser sintering. The current system incorporates a tether for the pressure sensing function.

Preliminary results: The device was evaluated in a simulated robotic procedure using a 50 g pancreas analog and two PrograspTM forceps controlled by the Intuitive daVinciTM Surgical System. The multi-jointed compliant nature of the deployable grasper allowed it to conform to the complicated geometry of the pancreas analog with easy, positive manipulation by the surgeon. The initial simulation suggested a re-design of the grasper to incorporate a more controllable twisting motion.

Conclusions/Future directions: Initial simulator testing was extremely promising. Future iterations will be made of biocompatible polymer instead of stainless steel greatly reduce overall weight. The pressure sensing function can be converted to RFID (radio frequency identification) technology. A twisting motion will be used to control the firing mechanism. A Patent application is pending.

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