Pulsed Electron Avalanche Knife: Intraocular Microsurg.
Principal Investigator: D V Palanker
Abstract: DESCRIPTION: This application proposes the further advancement of a highly precise low cost electrical cutting instrument based on pulsed plasma-mediated discharges in a liquid medium. Applications include traction-free removal of vitreoretinal membranes to avoid the risk of mechanical damage to the underlying retina associated with forces exerted by mechanical instruments. This device will also be applied for capsulotomy with no risk of rupture and mechanical stress to zonular fibers exerted during capsulorhexis. Additionally, capsulotomies will be created simply in eyes with poor visualization of the capsule, or with a miotic pupil. Applications to non-penetrating trabeculectomy and other ophthalmic and non-ophthalmic microsurgical procedures will be explored. This device also has coagulation, electro-adhesion and injection operating capabilities. During the last two years they have developed a device called Pulsed Electron Avalanche Knife (PEAK) for cutting soft tissue with 100 ns-long pulses of high voltage applied via a pointed electrode. This instrument was capable of precise dissection of soft tissue in liquid media, but certain limitations were found due to the following factors: (1) Individual pulses produce a series of perforations, which did not always merge into a continuous cut. (2) Depth and width of the cut were linked due to spherical geometry of cavitation bubbles. (3) The instrument did not dissect more fibrotic tissue such as sclera and cornea. (4) Pointed microelectrodes were not able to coagulate tissue. A much more advanced version of the instrument is presented in this proposal, which overcomes those previous limitations by (1) Application of an elongated electrode dissecting tissue with its cutting edges rather than with its apex; (2) Applying a burst of pulses instead of a single sub-microsecond pulse thus avoiding strong cavitation (3) Changing the mechanism of interaction from mechanical fragmentation to rapid vaporization and ionization will extend applicability to fibrous tissues; (4) A coagulation capability that can be achieved due to sufficiently large exposed area of elongated electrode. Implementation of the described proposal should result in creation of the most precise and broadly-applicable tractionless surgical device that will not only strongly improve precision and safety of the current surgical procedures but may lead to development of new microsurgical techniques. This device, allowing for "cold" dissection, coagulation, electro-adhesive manipulation of tissue and microinjection will also include illumination, irrigation and suction. It is miniaturizable to a 25 gauge size and can be incorporated into an endoscope. The low cost and small size of this system combined with high precision, reliability and versatility should allow for a widespread acceptance into operating practice.
Funding Period: 1999-12-01 - 2008-07-31
more information: NIH RePORT
- Electrosurgery with cellular precisionDaniel V Palanker
Department of Ophthalmology and Hansen Experimental Physics Laboratory, Stanford University, 452 Lomita Mall, Stanford, CA 94305 4085 USA
IEEE Trans Biomed Eng 55:838-41. 2008..This technology may allow for major improvements in outcomes of the current surgical procedures and development of much more refined surgical techniques...
- Pulsed electrical stimulation for control of vasculature: temporary vasoconstriction and permanent thrombosisDaniel Palanker
Department of Ophthalmology, Stanford University School of Medicine, Stanford, California 94305 4085, USA
Bioelectromagnetics 29:100-7. 2008..Histology demonstrated a lack of tissue damage during vasoconstriction, but vascular endothelium was damaged during thrombosis. The temperature increase does not exceed 0.1 degrees C during these treatments...
- Tissue damage by pulsed electrical stimulationA Butterwick
Department of Applied Physics, Stanford University, 445 Via Palou, Stanford, CA 94305, USA
IEEE Trans Biomed Eng 54:2261-7. 2007..061 A/cm2 at 6 ms to 1.3 A/cm2 at 6 micros. The highest ratio of the damage threshold to the stimulation threshold in retinal ganglion cells occurred at pulse durations near chronaxie-around 1.3 ms...
- Anterior capsulotomy with a pulsed-electron avalanche knifeDaniel Palanker
Department of Ophthalmology and Hansen Experimental Physics Laboratory, Stanford University, Stanford, California 94305 4085, USA
J Cataract Refract Surg 36:127-32. 2010..To evaluate a new pulsed-electron avalanche knife design for creating a continuous curvilinear capsulotomy (CCC) and compare the CCC with a mechanical capsulorhexis...