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Proceedings Paper

Optimization of the pulsed electron avalanche knife for anterior segment surgery
Author(s): Daniel V. Palanker; Alexander Vankov; Kalayaan Bilbao; Michael Marmor; Mark Scott Blumenkranz
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Paper Abstract

Precise and tractionless tools are needed for cutting and ablation of ocular tissue in such operations as vitreoretinal surgery, capsulotomy, non-penetrating trabeculectomy and many others. Previously we reported about the Pulsed Electron Avalanche Knife capable of tractionless dissection of soft tissue in liquid media using the 100 ns-long plasma-mediated electric discharges applied via a 25 um inlaid disk electrode. In this work we present a next step in the development of this technique, which dramatically improves its precision, the cutting rate and the scope of applicability. (1) Due to spherical geometry of the discharge with the disk-like microelectrode the width of the cut was equal to its depth. To overcome this limitation we apply now a thin cylindrical electrode where the width and the depth of the cut are controlled independently. (2) Cavitation accompanying the sub-microsecond explosive evaporation was a major limiting factor in precision of this technique. In a new modality we apply bursts of pulses, which allow for much higher energy deposition without increase in the size of the transient vapor cavity. (3) Coagulation regime for blood vessels larger than 25 microns in diameter was not possible in the initial approach. It is now available due to extension of the electrode in one dimension. (4) Increase in pulse duration up to several tens of microseconds allows for reduction in voltage and, consequently, in width of the insulator. This, in turn, enables development of the ultra-thin electrodes that can be applied via an intraocular endoscope or 25 G needles. The new device was found capable of rapidly and precisely dissecting virtually all types of ocular tissue: from soft membranes to cornea and sclera. In addition to vitreoretinal surgery it applications can now expand into anterior chamber surgery including capsulotomy and trabeculectomy.

Paper Details

Date Published: 14 July 2003
PDF: 6 pages
Proc. SPIE 4951, Ophthalmic Technologies XIII, (14 July 2003); doi: 10.1117/12.477954
Show Author Affiliations
Daniel V. Palanker, Stanford Univ. (United States)
Alexander Vankov, Stanford Univ. (United States)
Kalayaan Bilbao, Stanford Univ. (United States)
Michael Marmor, Stanford Univ. (United States)
Mark Scott Blumenkranz, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 4951:
Ophthalmic Technologies XIII
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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