Cryogenic surgical instrument
AssigneeErbe Elektromedizin GmbH
InventorJohannes T. M. van Gerven
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Abstract
To insulate the supply lines to an operating tip of a cryogenic surgical instrument, a coaxial assembly of tubes is provided, the inner one being connected to a supply of cryogenic liquid, such as liquid nitrogen; the space between the outer wall of the inner tube and the next tube forming a return line for evaporated cryogenic liquid which is vented to the atmosphere; and the space between the outermost one of the coaxial tubes and the intermediate tube containing a gas such as normal butane, introduced at atmospheric pressure and which has high heat-insulating properties, and which solidifies, or sublimates, to avoid a vacuum and make possible construction of the supply lines as plastic, preferably polyamide tubes, retaining flexibility in use.
Claims10
Cryogenic surgical instrument to supercool limited areas of biological tissue having
- a hollow tip (21) of thermally conductive material, a supply vessel (1) of supercooled cryogenic liquid,
- a supply line (11) connected to said supply vessel (1) and to the hollow interior of the tip (21),
- a return line coaxial with said supply line and surrounding the same, said return line comprising two coaxial tubes (13, 15) spaced from each other and defining a heat-insulating space (14) therebetween, the inner one of the coaxial tubes (13) being spaced from the supply line (11) to define a return space (12) for evaporated cryogenic liquid,
- and a filler material comprising n-butane in said insulating space (14).
Dependencies are inferred from the claim text.