Stone retriever for flexible endoscopes having small diameter working channels

A stone retrieval system for use within a working channel of a flexible endoscope, said endoscope having an optical system for transmitting images proximate a distal end of said endoscope, said working channel having an inner diameter of less than 3.7 Fr, said stone retrieval system comprising:

• a lithotripsy device adapted to be inserted in said working channel of said flexible endoscope;
• a medical retrieval device adapted to be inserted into said working channel of said flexible endoscope, said medical retrieval device including:
• a basket formed from a plurality of flexible elements and having a substantially tipless configuration, at least one of said flexible elements are distally joined non-parallel when said basket is open, in which said flexible elements having a plurality of different cross sectional shapes along a longitudinal length of said flexible element, each of said cross sectional shapes being generally uniform along a first portion of said longitudinal length and along a second portion of said longitudinal length with said cross sectional shapes along said first portion having a different corresponding thickness than said cross sectional shapes along said second portion, said thickness being a cross sectional dimension of said flexible element along a line defined perpendicular to said flexible element and coplanar with a longitudinal axis of said basket;
• a sheath comprising a lumen, a distal end and a proximal end, said sheath having an average outside diameter range of less than 1.7 Fr;
• and
• a drive wire slidably disposed within said sheath and operably attached at a distal end to said basket such that said drive wire operably manipulates said basket by sliding said drive wire within said sheath;
• and
• a source of irrigation fluid fluidly coupled to said endoscope to introduce irrigation fluid into a proximal portion of said working channel at an irrigation flow rate,
• wherein said irrigation flow rate exiting a distal portion of said working channel is sufficient for stone visualization via said optical system when both said lithotripsy device and said medical retrieval device are simultaneously positioned in said working channel.

A medical retrieval device for use within a working channel of a endoscope comprising:

• a basket formed from a plurality of flexible elements and having a substantially tipless configuration, in which said flexible elements are distally joined non-parallel when said basket is open, at least two of said flexible elements having a plurality of different cross sectional shapes along a longitudinal length of said flexible element, each of said cross sectional shapes being generally uniform along a first portion of said longitudinal length and along a second portion of said longitudinal length with said cross sectional shapes along said first portion having a different corresponding thickness than said cross sectional shapes along said second portion, said thickness being a cross sectional dimension of said flexible element along a line defined perpendicular to said flexible element and coplanar with a longitudinal axis of said basket;
• a sheath comprising a lumen, a distal end and a proximal end, said sheath having an average outside diameter of less than 1.7 Fr where said sheath is operably engaged within said working channel;
• and
• a drive wire slidably disposed within said sheath and operably attached at a distal end to said basket such that said drive wire operably manipulates said basket by sliding said drive wire within said sheath;
• whereby said outside diameter of said medical retrieval device provides reduced flow resistance to irrigation fluid within said working channel.

A medical retrieval device for use in a medical procedure for extraction of a stone, the device comprising:

• a sheath having a proximal end and a distal end and defining a lumen there between:
• a basket formed of a plurality of wires having:
• a closed configuration when said basket is retracted within said distal end of said sheath, and
• an open configuration when said basket is extended from said distal end of said sheath to define an entrapment space for entrapping a stone, said open configuration including a proximal portion and a distal position having a substantially tipless configuration,
• at least two of said wires having a plurality of cross sectional shapes, said cross sectional shapes being generally uniform along a longitudinal portion of the wire, and each of said cross sectional shapes having a different corresponding thickness, said thickness being a cross sectional dimension of said wire along a line defined perpendicular to said wire and coplanar with a longitudinal axis of said basket;
• a drive wire which is able to move within said sheath and is connected to said basket at said distal portion such that said drive wire is able to push said basket out of said sheath into said open configuration or pull said basket into said sheath into said closed configuration.