Disposable cryosurgical instrument

Claim 1

In a one-use, throw-away, leak-proof, syringe-type cryosurgical instrument of the type comprising: a longitudinal housing forming a cavity therein for holding a cryogenic fluid; means to conduct cold from said cavity inside of said housing to the outside thereof at one end of said housing, said means including a surgical probe formed of a thermally conductive material, said means being in contact with said cryogenic fluid on the inside of said housing when said instrument is in its operative position; means to trap cryogenic liquid within said housing, said trap means being located at the end of said housing opposite from said probe, said trap means comprising an axially directed internally projecting element having a large opening located at the end of said housing opposite said probe and a small opening located intermediate the two ends of said housing, said trap means having a thin elongated element for defining a large annular trap space thereabout within said cavity, said trap means aiding the insertion of cryogenic fluid within said housing while preventing said cryogenic fluid in liquid form from leaving said housing after said fluid has been inserted therein; and actuator cap means for feeding cryogenic liquid into said cavity through said elongated element while disposed in vertical position with said probe projecting upwardly, said actuator cap means comprising a receiver element for mating with the valve of an aerosol can, and a narrow elongated tube of length greater than the length of said thin elongated trap element; the improvement wherein a tip portion of said narrow elongated tube which extends beyond said thin elongated trap element into said cavity during cryogenic-liquid feeding has a radially directed opening therein for feeding cryogenic liquid into said housing radially without causing contact of the cryogenic fluid with said thermal conducting means during said feeding.