Abstract
Abstract: :
Purpose: To develop silicon microforceps for intraocular surgery using MEMS technology, the application of microchip fabrication techniques to produce movable, controllable three–dimensional devices on the micron scale. Methods: A variety of MEMS forceps prototypes were manufactured of single crystal silicon at the microfabrication facility of the Berkeley Sensor and Actuator Center. Designs using both thermoelectric actuators and conventional mechanical handles were employed to open and close the forceps. Forceps were tested for functionality in human cadaver eyes and rabbit eyes in vivo using standard vitreoretinal surgery. Results: MEMS forceps were constructed with tip sizes ranging from 200 microns to 2 mm. Scanning electron microscopy confirmed accurate construction of microfeatures such as forceps teeth designed as small as 10 microns. Surgical videos demonstrated that in cadaveric and rabbit eyes the forceps tips were sufficiently durable and rigid for repetitive vitreoretinal surgical maneuvers, including grasping retinal membranes and excising tissue. Heat dispersion plates in the thermoelectric actuator design were found to malfunction due to surface protein coagulation; mechanical spring–activated handles were successful in the environment of the vitreous cavity. While handheld operation was possible, the precision of the forceps was best exploited when mounted on a 3–axis micromanipulator. Conclusions: MEMS microforceps are feasible for conventional vitreoretinal surgery, and offer advances in small scale and precision.
Keywords: vitreoretinal surgery • retina • microscopy: electron microscopy