Patent ID: 8523879

Claim:
A medical retrieval device for use within a working channel of a flexible endoscope, said flexible endoscope having a deflectable portion, said medical retrieval device comprising: a sheath having a lumen, a distal end and a proximal end; a drive wire slidably disposed within said lumen, said sheath and said drive wire each having a distal portion, a proximal portion, and an intermediate portion, said intermediate portion located between said distal portion and said proximal portion, each of said portions of said sheath being generally longitudinally aligned proximate with the corresponding ones of said portions of said drive wire; and a stone entrapping mechanism formed from a plurality of flexible elements and having a substantially tipless configuration and adapted to be deployed proximate said distal portion of said sheath and operably connected to said distal portion of said drive wire, at least two of said flexible elements are distally joined non-parallel when said stone entrapping mechanism 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; wherein said sheath has an average outside diameter of less than 1.9 Fr, said intermediate portion or said distal portion of said drive wire is more flexible than said proximal portion of said drive wire, and said intermediate portion of said sheath is generally similar in stiffness to said proximal portion of said sheath such that said intermediate portion of said medical retrieval device is sufficiently flexible so as to permit flexure of said deflectable portion of said flexible endoscope, whereby said outside diameter of said medical retrieval device provides reduced flow resistance to irrigation fluid within said working channel.