Abstract
Abstract: :
Purpose: To develop a more precise and less traumatic device to grasp and lift delicate tissues, such as the internal limited membrane (ILM) during vitreoretinal surgery. We present the concept of electrically–induced adhesion of tissue. Methods: Conductive microprobes of 50 µm in diameter and 0.2–0.6 mm in length were activated by bi–phasic burst waveforms with pulse durations varying in the range of 0.1 – 1 ms. Adhesive forces were measured on chick chorioallantoic membrane using a microdynamometer. The size of the collateral damage zone assessed histologically, and by staining with physiological markers. Results: The microprobe displayed adhesive properties after application of a pulse within the voltage range of 60–200V. Maximal adhesive force per unit length of the probe was about 2 mN/mm (or 0.2 g per mm of length), which is sufficient for any intraocular tissue manipulation. The adhesive force was stable over time with no further electrical pulses required to maintain it. To disconnect the probe from the tissue a single pulse at higher voltage is applied, which creates a few micrometers–thick transient vapor cavity around the electrode. This vapor cavity pushes the captured tissue away from the probe thus releasing it. Propidium iodide staining of the live tissue demonstrates that the collateral damage zone extends no more than 10–20 µm from the probe. Conclusions: Capturing and manipulation of thin and evasive membranes can be performed with electro–adhesive technique in an easier and less traumatic manner than with conventional forceps. This technique may be applicable to various types of ophthalmic microsurgery, including internal limiting membrane and lens capsule dissection.
Keywords: retina • vitreoretinal surgery