Cryosurgical instrument

Claim 1

A cryosurgical instrument comprising: means defining a body having opposing extremities and provided with an elongate bore therein extending through the surface of said body means to define a receiving opening in one extremity of said body means, said body means including a refrigerant fluid inlet passageway therein communicating with said bore at a first point spaced from said receiving opening and adjacent the opposite extremity of said body means, said refrigerant fluid inlet passageway being adapted to be coupled with a source of refrigerant fluid, said body means further including a refrigerant effluent outlet passageway therein communicating with said bore at a second point between said receiving opening and said first point; a kit including first and second, unitary, integrated cryotip assemblies, said first cryotip assembly having a distal and a proximal end and comprising (1) an outer, elongate, hollow tube having a distal and a proximal end, the distal end thereof being closed to define a gas expansion chamber, said outer tube having an exhaust opening therein adjacent the proximal end thereof, and (2) an inner, elongate, hollow tube for supplying refrigerant to said expansion chamber, having a distal and a proximal end and being concentrically disposed within said outer tube such that the distal end of the inner tube opens into said expansion chamber and the proximal end of said inner tube is located adjacent the proximal end of said outer tube, said inner tube being radially spaced from the outer tube to define an annular exhaust channel between said inner and outer tubes communicating with said exhaust opening in said outer tube, said inner tube being secured to said outer tube and having both ends thereof essentially open, said second cryotip assembly having a distal and a proximal end and comprising (1) an outer, elongate, hollow tube having a distal and proximal end a refrigerant fluid delivery opening in the distal end thereof, the proximal end of said last named tube being closed, and (2) an inner, elongate, hollow tube for supplying refrigerant to said delivery opening, having a distal and a proximal end, said last named inner tube being disposed within said last named outer tube such that the distal end of the inner tube opens into said delivery opening and the proximal end of said inner tube is located adjacent the proximal end of said outer tube and having each end thereof essentially open, said last named inner tube being secured to said last named outer tube; the proximal end of each of said cryotip assemblies being sized such that each of said cryotip assemblies may be received within said bore, manipulable means for selectively securely either of said first and second cryotip assemblies on said body means, said manipulable securing means including a first portion carried by each said first and second cryotip assemblies, and a second portion carried by said body means adjacent said receiving opening, the proximal ends of each of said cryotip assemblies being such that when either of said cryotip assemblies is secured to said body means said proximal end of said inner tube extends to a position within said bore between said first and second points, first means for providing a fluid seal between said inner tube and said body means at an area in said bore between said first and second points such that when either of said cryotip assemblies is secured to said body means refrigerant fluid entering said bore from said inlet passage is directed into said proximal end of said inner tube, the outer tube of said first cryotip assembly being such that when said first cryotip assembly is secured to said body means and said outer tube of said first cryotip assembly extends to a position within said bore between said receiving opening and said first fluid seal means such that said exhaust opening in said outer tube of said first cryotip assembly is in fluid communication with said outlet passage, second means for providing a fluid seal between said outer tube of said first cryotip assembly and said body means at an area in said bore between said second point and said receiving opening such that refrigerant fluid exhausted through said exhaust opening is directed to said outlet passage, said first and second portions of said manipulable securing means being releasably engagable with each other for releasably securing the corresponding one of said first and second cryotip assemblies on said body means, with said open end of said outer tube of said first cryotip assembly extending into said bore through said receiving opening when said first cryotip assembly is secured to said body means, and with the closed end of said outer tube of said second cryotip assembly extending into said bore through said receiving opening when said second cryotip is secured to said body means, each of said first and second cryotip assemblies being removable as an integral unit from said body means by operation of said manipulable securing means to permit interchangeably securing either of said first and second cryotip assemblies to said body means.