Distal Force Sensing in 3D for Actuated Instruments: Design, Calibration and Force Computation

Unmet Need
Retinal microsurgery requires the careful manipulation of delicate tissues by exerting minute amounts of force which lie below the tactile sensory threshold of surgeons. Thus, motorized instruments with force sensing are needed to perform tasks such as membrane peeling - a process where the fibrous tissue is delaminated off the retina by applying very fine forces. There are existing ophthalmic surgery tools that accurately measure the forces in 2 dimensions, as well as static tools that can measure applied forces in 3 dimensions. However, these tools’ efficacy are limited in a surgery that requires active manipulation of the retina in a 3D environment. Thus, there is a need for an actuated (non-static) instrument that can measure forces in 3 dimensions to ensure that critical forces are maintained at a secure level during retinal microsurgery.

Technology Overview
This invention describes an actuated instrument that firmly grasps and relocates delicate tissues during microsurgery while accurately measuring device-tissue interaction forces in 3 dimensions. The device preserves the grasping functionality of micro-forceps, giving it less slippage due to its firm gripping potential. Additionally, its decreased tool diameter means it can fit through small openings and allows for more precise manipulation of the retinal surface. The accuracy of grip and force measurements of the tool decreases the attempts needed to initiate membrane peel, reducing risk of clinical complications due to excessive forces.

Stage of Development
Prototype validation.

Publications
K. Nakata et al Graefes Arch Clin Exp Ophthalmol. 241: 582-584, JUL 2003

Category(s):