all of the following embodiments of the invention generally have at least one thing in common , a basket of a medical retrieval device having a substantially atraumatic tip according to the invention . the basket 10 , shown by way of example in fig1 f , is the type that can be collapsed within a sheath 12 for entry into the body . a medical device or extractor that includes the basket 10 of the invention also includes the sheath 12 and a proximal handle 8 . the handle 8 , sheath 12 , and basket 10 illustrated in fig1 e and 1 f are not shown in their correct size or proportion to each other . the size of the entire sheath is dimensioned to fit the requirements of its application in the body . for example , for urological applications , the size of the device is typically 1 . 7 - 8 . 0 fr . the sheath 12 has at least one lumen 14 therein , may be made from a single material , and extends from the handle 8 to a distal sheath end 16 . an elongated member such as a cable , coil , shaft , guidewire or mandril wire 18 extends within the lumen 14 from an actuating mechanism 4 at the device handle 8 to the base 20 of the basket 10 , where the cable 18 is attached to the basket base 20 . operation of the actuating mechanism 4 by an operator causes the basket 10 to move in and out of the sheath 12 between a collapsed position within the sheath 12 as illustrated in fig1 f to an extended position outside of the sheath 12 where the basket 10 is open / expanded and extending beyond the distal end of the sheath 16 as shown in fig1 e . alternatively , the mechanism 4 can cause movement of the sheath 12 to advance the sheath 12 over the stationary basket 10 and cable 18 combination , to thereby collapse the basket 10 within the sheath 12 , and the mechanism 4 can slide the moveable sheath 12 back to expose the stationary basket 10 and allow it to open / expand . in general , both types of basket / sheath movement configurations and related handle mechanisms are known , and can be seen in existing product designs available from , for example , boston scientific corporation ( natick , mass .). with the basket collapsed within the sheath 12 as shown in fig1 f , the sheath 12 can be inserted into the body by an operator to a site in the body where the material to be retrieved is located ( e . g ., a stone in the ureter ). by putting the basket 10 into its open / expanded position , as illustrated in fig1 e , the basket 10 dilates the body tract in which it has been placed and can be manipulated by the operator to entrap or capture material within the basket 10 . the basket 10 and / or the sheath 12 can then be moved to cause the legs 11 a , 11 b , 11 c , 11 d of the basket 10 to close around the material and capture it . the captured material is then withdrawn from the body along with the sheath and the basket that is holding the material . in one aspect , according to the invention , a basket 10 of a device for retrieving biological or foreign material from a body has a plurality of legs , for example , as shown in fig1 b , four legs 11 a , 11 b , 11 c , 11 d . an end - on view of the basket 10 in fig1 d illustrates a substantially tipless or atraumatic distal end 100 . a small , insubstantial protrusion or depression may remain at the distal tip as a result of the manufacturing process . such features on the basket tip do not poke , tear , pierce , perforate , bruise or otherwise inflict injury or cause trauma to the tissue and may enhance basket performance . in one embodiment , for example , the legs 11 a , 11 b , 11 c , 11 d and the atraumatic basket 10 can be cut , etched , stamped or otherwise removed as a single shape or profile from a substantially flat piece of material 101 as illustrated in fig1 a . in another embodiment , referring to fig1 e , 1 g and 6 b , just the distal end portion 5 of the basket 10 is removed as a single shape or profile from a single piece of substantially flat material . alternatively , the basket 10 or distal end portion 5 can be injection molded into the desired shape by , for example , plastic injection molding , metal - injection - molding ( mim ) or by compression of metal powders . as illustrated in fig1 a and fig1 c , the starting profile for the basket 10 or the basket end portion 5 can be an x - profile or x - shape . after removal of the x - profile from the flat material , the three - dimensional basket or distal end portion 5 of the basket 10 can be formed by bending and shaping the legs of an x - profile . the starting profile may be asymmetrical . for example , in other embodiments , the starting profile of the basket 10 or the distal end portion 5 can be y - shaped , t - shaped or star - shaped . with continued reference to fig1 b and 1d , the distal end 100 of the basket 10 is uniform , contoured , and substantially without any protruding surface features . that is , in accordance with the invention , the distal end 100 of the basket 10 is substantially devoid of knobs , protrusions , fasteners , or outward projections . the distal end 100 of the basket 10 may be perforated 20 as illustrated in fig1 g to permit a guidewire ( not shown ) to extend through the sheath 12 and out the end of the basket 10 through the perforation 20 . referring to fig1 h , alternatively , a ram - rod , laser or other lithotriptic device 9 is longitudinally disposed in a channel 200 of sheath 12 . channel 200 extends through the proximal end 20 of the basket 10 . in operation , a stone 50 is captured in the lumen of the basket 10 . the lithotriptic device is advanced beyond the proximal basket end into the basket until the lithotriptic device approaches the stone 50 . the stone 50 is then fragmented by lithotripsy . the fragmented stones are removed from the body while entrapped within the basket 10 . no adhesive or any other attachment material or device is used at the distal end 100 of the basket 10 to hold the legs together as at least the distal ends of the legs are formed by a profile including distal leg portions extracted from a single piece of sheet - like material as illustrated in fig1 a and 1c to form a tipless atraumatic three - dimensional basket as illustrated in fig1 b . the distal end 100 of the basket 10 is substantially atraumatic in that it has no substantial outward projections or protrusions that might cause injury or trauma to tissue and / or that might present an impediment to contacting the distal end 100 of the basket 10 directly and intimately with tissue . in one embodiment , referring to fig2 a - 2e , a medical device of the invention includes a plurality of legs forming the basket 10 . the legs can have various cross - sectional shapes , for example , as shown in fig2 d and 2e . other cross - sectional shapes for the legs of the basket 10 include , but are not limited to , a d - shape , a v - shape , a b - shape , rectangular , and cylindrical ( not shown ). typically , the length of the legs 11 a , 11 b , 11 c , 11 d is about 0 . 5 to 3 . 5 inches , for example , 1 . 1 to 1 . 5 inches , the width of the leg is about 0 . 005 inches to 0 . 015 inches and the thickness of the legs is 0 . 028 inches to 0 . 045 inches . the ends 1 of the basket legs 11 may be modified by narrowing , enlarging or grooving the end for example , as shown in fig2 f , to ease assembly and / or strengthen the basket when the ends of the basket legs are brought together . referring to fig2 a - 2c and 2 e , a typical basket end portion may have the following features . the basket end portion can have four legs , the legs being approximately 90 ° apart . the leg length d 1 is 1 . 1 inches to 1 . 25 inches , leg width d 2 is 0 . 010 inches to 0 . 012 inches , leg width d 3 is 0 . 006 inches to 0 . 008 inches , and leg thickness d 4 is 0 . 005 ± 0 . 0003 to 0 . 0032 ± 0 . 003 inches . at the intersection 121 of the four legs , the four corners have a slight radius as shown in fig2 b . the ends 1 of the legs as illustrated in fig2 c have a full radius . notches or cut - outs 123 are located 0 . 100 inches ( d 6 ) from the end 1 of the leg and have a radius of 0 . 003 - 0 . 004 inches with a minimum distance ( d 5 ) of 0 . 004 inches between the apex of the notches . the “ x ” profile illustrated in fig2 a may be removed from a flat annealed , superelastic , nickel - titanium sheet having a pickled surface and active a f of 15 ± 5 ° c . the basket 10 or distal end 100 of the basket 10 can be formed from various materials such as stainless steel , metal alloys , superelastic materials , shape memory materials , powdered metals , ceramics , thermal plastic composites , ceramic composites , polymers , etc . also , combinations of these and other materials can be used . the atraumatic basket 10 can assume shapes more complex than one with three or more legs running parallel and longitudinally from the distal end of the basket to the basket base . for example , referring to fig3 a , a single - unit hourglass profile 22 can be removed from a single piece of sheet - like material 101 by stamping , etching , or cutting , for example , according to the invention . a three - dimensional basket 10 can be created by folding the single - unit hourglass profile , as illustrated by the arrows in fig3 a , into a substantially parachute - shaped configuration as shown in fig3 b . heat treatment , cold - forming , or other shaping processes using a ball - shaped die is then performed on the parachute - shaped configuration to shape the profile into a three - dimensional basket 10 . the distal end 100 of this basket 10 is tipless and atraumatic . the proximal end 24 of basket 10 can be joined to a cable 18 within a sheath 12 as illustrated in fig3 c . the basket 10 is moveable relative to the sheath 12 from a collapsed basket position , shown in fig3 c to an open basket position shown in fig3 d . in another embodiment , the basket can be made by extracting a single unit web - shaped profile 26 , as illustrated in fig4 a , from a single piece of sheet - like material . the web - profile is removed from a single piece of sheet - like material by stamping , etching or cutting , for example . the web - profile is subsequently shaped and molded around a ball shape by heat treatment , cold - forming , or other shaping processes to achieve a basket 10 as illustrated in fig4 b . the distal end 100 of this basket 10 is atraumatic and substantially tipless . the proximal end 24 of basket 10 can be joined to a cable ( not shown ) and the basket can be moved within the lumen of a sheath relative to the sheath in a manner similar to the basket illustrated in fig3 c and 3d . referring to fig5 another embodiment of the basket can be made by extracting a single unit double - loop profile 28 from a single piece of material by stamping , etching , or cutting , for example . the double - loop profile 28 is shaped and molded around a ball shape by heat treatment , cold - formed , or by other shaping processes , to form the basket 10 illustrated in fig5 b . the distal end 100 of the basket 10 is substantially tipless and atraumatic . the proximal end 24 of the basket can be joined to a cable ( not shown ) and the basket can be moved within the lumen of a sheath , relative to the sheath in a manner similar to the basket illustrated in fig3 c and 3d . to manufacture a basket according to the invention , a single piece of flat material , such as a sheet of metal , or a single piece of material contoured to conform to the basket radius is used to form the distal basket tip . when starting with a single piece of flat material , at least the distal basket tip is defined by a shape or profile that is removed from the single piece of construction material . the profile can be removed from the material by a variety of methods including , for example , stamping , etching , photoetching , or laser cutting as illustrated in fig1 a or 3 a . the profile removed from the single piece of material is then shaped by heat treatment , cold - forming process or by other processes known in the art to form at least a distal end portion 5 as illustrated , for example , in fig1 g and 6b having an atraumatic distal tip , or a three - dimensional basket structure , for example , as illustrated in fig1 b , 3 b , 4 b and 5 b having an atraumatic distal tip . alternatively , the basket legs may be rotated or twisted slightly around their longitudinal axis to achieve a helical basket , for example , as shown in fig1 d . a basket according to the invention also can be formed by injection molding the distal basket portion or desired basket profile . alternatively , with a metal or plastic injection molding process , the three - dimensional distal basket portion or basket design can be injected into a three - dimensional mold thereby obviating the step of shaping the distal basket portion or basket structure following removal of the profile from a single piece of construction material by molding into a final shape . the basket 10 and basket designs described below are joined at the basket proximal end to the distal end of the elongated member 18 to form a subassembly . the basket / elongated member subassembly is inserted into the sheath 12 and joined to the handle 8 to form the medical retrieval device according to the invention . the “ x ” profile that is shown in fig6 a , for example , can be replaced by any other shape that lends itself to clinical efficiency and manufacturability and that results in a substantially tipless atraumatic basket . the “ x ” or other profiles can have a small , atraumatic protrusion or depression at the distal basket tip . also , the “ x ” profile or other profile , can be shaped to make a distal end portion 5 of the basket 10 , and leg extensions 3 a , 3 b , 3 c , 3 d can be added to end - sections 1 a , 1 b , 1 c , 1 d of legs 11 a , 11 b , 11 c , 11 d to form all of or a portion of the basket legs 11 a , 11 b , 11 c , 11 d as shown in fig6 b . alternatively , the end - sections 1 a , 1 b , 1 c , 1 d of the basket legs 11 a , 11 b , 11 c , 11 d of the “ x ” profile or any other profile can be secured together at the base 20 of the basket 10 illustrated in fig7 a . all or a portion of the inner surface ( side toward basket center ) of one or more of the basket legs can be treated to enhance the ability of the basket to grasp and hold material to be retrieved . for example , an anti - slip coating , such as a rubberized or plastic coating can be applied to at least a portion of the inner surface of at least one of the basket legs as illustrated on the inner surface 15 of leg 11 b in fig7 a . the coating can be applied directly to the single piece of sheet - like material from which the basket profile is extracted before basket formation or to the inner surface of the basket legs after basket formation . an enhanced grasping and / or fragmentation capability also can be achieved by adding texture to at least the inner surface of at least one of the basket legs by , for example , creating serrations , teeth , or points on the inner surface ( s ). this can be achieved by , for example , etching , pitting , bending , stamping or machining the texture / roughness into the inner surface ( s ) by application of these methods directly to the single piece of sheet - like material from which the basket or basket distal end shape is extracted before basket formation , or directly to the inner surface of the basket legs after basket formation . referring to fig6 a , 7 b , and 8 , according to one embodiment of the invention , a profile stamped from a single piece of sheet - like material has end - sections 1 that are brought together at a basket base 20 to form a three - dimensional basket 10 . alternatively , as illustrated in fig6 a and 6b , just the distal end portion 5 of the basket can be formed from the single piece of construction material with the legs of the basket extending from the end - sections 1 a , 1 b , 1 c , 1 d of the profile and then drawing the end - sections 1 a , 1 b , 1 c , 1 d down and bringing the end - sections together at the basket base 20 to form the basket 10 . as shown in fig8 it is possible to have more than three or four basket legs by forming the basket distal end from , for example , an eight - leg 11 a , 11 b , 11 c , 11 d , 11 e , 11 f , 11 g , 11 h star - shape profile 28 extracted as a single unit from a single piece of sheet - like material . the shape forming the distal end portion of the basket may be asymmetrical . baskets that are atraumatic and tipless may also have each leg 11 a , 11 b , 11 c , 11 d joined at the distal end 100 of the basket in a variety of ways such as by spot welding the legs at the distal end 100 as illustrated in fig9 or by looping two or more wires 17 a , 17 b together at the distal end 100 as illustrated in fig1 . the wires are looped together by forming a loop in a mid - portion of the first wire 17 a . second wire 17 b is passed through the loop of the first wire 17 a . the second wire 17 b is looped within and is held by the loop of the first wire 17 a . referring to fig1 a and 11b , in another embodiment of the invention , a tipless end 130 of the atraumatic basket 10 is constructed by using single wires to form loops 120 a , 120 b having legs 11 a , 11 b , 11 c , 11 d extending from the apex 130 a , 130 b of the loops 120 a and 120 b , respectively , the apex 130 a , 130 b positioned at the basket distal end 100 . a plurality of pre - formed wire loops is included in a three - dimensional , atraumatic basket . wire loops may be formed from plastics , superelastic materials , stainless steel , shape memory metals , ceramic composites , other composites , or other materials and may have any of a variety of cross sectional shapes such as d - shape , b - shape , u - shape , round , half - round , oval , rectangular or ribbon - like . in this embodiment of an atraumatic wire basket , two wire loops 120 a , 120 b , for example , may be used to form a basket with four legs 11 a , 11 b , 11 c , 11 d as shown in fig1 a , and three wire loops 120 a , 120 b , 120 c may be used to form a basket with six legs 11 a , 11 b , 11 c , 11 d , 11 e , 11 f as shown in fig1 b . additional wire loops may be used to form a basket with more than the four or six legs shown . the apex 130 of each wire loop 120 intersects the apex 130 of the other wire loops 120 of the basket 10 at the basket distal end 100 . the wire loops 120 at the basket distal end 100 are free to slide by one another , i . e ., they are not affixed , fused , soldered , welded , glued , joined , secured or attached to one another . the advantages of this configuration of the basket is that the basket end 100 is atraumatic and provides flexibility thereby enhancing the ease by which stones are captured . the two end - sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding , soldering , ligating , gluing , crimping or any other means known in the art . in one embodiment , the end - sections 1 , 1 ′ of the wire loops are affixed ( not shown ) to a cable , coil , shaft , mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in fig1 e and fig1 f . referring to fig1 c and 11d , the tipless end 100 of the atraumatic basket can also be constructed by using single pre - formed wires to form modified loops 120 , each modified loop having a pair of legs 11 a , 11 b extending from the apex 130 of the loop 120 , the apex 130 positioned at the basket distal end 100 . the apex 130 of a pre - formed wire loop 120 forming pairs of basket legs is modified to stabilize the basket tip . for example , as illustrated in fig1 c , the apex 130 of a wire loop 120 is modified by a protrusion 140 with a radius , such as a semi - circular protrusion . a basket may be formed by a plurality of wire loops 120 a , 120 b , each wire loop having a small protrusion 140 a , 140 b with a radius , as illustrated in fig1 d . each semi - circular protrusion on the basket wire has a convex surface 142 and a concave surface 144 as illustrated in fig1 c . in this embodiment , the convex surface 142 of the semi - circular protrusion 140 of wire loop 120 a meets the concave surface 144 of the semi - circular protrusion 140 of the outer wire loop 120 b where the wires of the basket cross one another at the basket distal tip 100 as illustrated in fig1 d . at the apex 130 where the loops cross one another at the distal end of the basket , the wires forming the loops are not adhered , affixed , fused , soldered , welded , glued or joined to one another . typically , two or more wires ( i . e ., loops ), each with a semi - circular protrusion , are used to form an atraumatic wire basket . wire loops 120 may be formed from superelastic materials , stainless steel , shape memory metals , ceramic composites , other composites , or other materials and may have any of a variety of cross sectional shapes such as d - shape , b - shape , u - shape , round , half - round , oval , rectangular , or ribbon - like . in this embodiment of an atraumatic wire basket , for example , two wire loops 120 a , 120 b may be used to form a basket with four legs as shown in fig1 c , or three wire loops may be used to form a basket with six legs ( not shown ), and so on . additional wire loops may be used to form a basket with more than the four or six legs shown . referring to fig1 c , the two end - sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding , soldering , ligating , gluing , crimping or any other means known in the art . the end - sections 1 , 1 ′ of the wire loops can be affixed as shown in fig1 d to a cable , coil , shaft , mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in fig1 e and fig1 f . a channel 200 may run through the sheath 12 and the proximal end 20 of the basket 10 to accommodate a ram - rod , laser or other lithotriptic device 9 as shown in fig1 h and described earlier . a basket of the invention having two or more wire loops 120 a , 120 b each with semi - circular protrusions 140 at the apex 130 of the loops 120 a , 120 b , has enhanced basket stability and dilatative strength without substantially compromising basket flexibility . in this embodiment of the invention ( fig1 c and 11 d ), the wires are unlikely to slide by one another at the distal tip . the semi - circular protrusions also help to reduce the stress on the basket legs while closing the basket . the legs of an atraumatic wire basket 10 illustrated in fig1 a - 11d and fig1 a - 12d may be gently curved or may have a plurality of angular bends . in one embodiment , illustrated in fig1 a , each of the legs 11 a , 11 b of a loop 120 a have five angular bends , 17 a , 17 a ′, 17 a ″, 17 a ′″, 17 a ″″ forming at least two shoulders 15 ′ and 15 ″ on each leg 11 a , 11 b of the wire loop 120 . a three - dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in fig1 a is shown in fig1 b . fig1 a illustrates a wire loop 120 configuration where all of the angles 17 of the loop are obtuse . a three - dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in fig1 a is shown in fig1 c . an infinite number of obtuse angles in both legs of the wire loop results in a smoothly curved loop as illustrated in fig1 b . a largely oval or round , atraumatic three - dimensional basket shape 10 formed by two basket loops 120 a , 120 b of the type illustrated in fig1 b is shown in fig1 d . the legs 11 a , 11 b , 11 c , 11 d of the baskets illustrated in fig1 b , 11 d , 12 c and 12 d may be pre - formed , and their cross - section may be b - shaped , d - shaped , u - shaped , round , half - round , oval , rectangular , ribbon - like , or a variety of other cross - sectional shapes such as those shown in fig2 d and 2e . in yet another embodiment of an atraumatic wire basket illustrated in fig1 a , the distal ends 3 a , 3 b , 3 c , 3 d of the basket wires 3 insert into a cap 160 with a core 170 at the basket tip 100 as shown in fig1 c . the distal ends 3 a , 3 b , 3 c , 3 d of the wires are affixed to the cap 160 by soldering , gluing or any means known in the art . the wires emerging from the cap are bent and then drawn down proximally as indicated by the arrows in fig1 b to form basket legs 11 a , 11 b , 11 c , 11 d . the end - sections of the legs 1 a , 1 b , 1 c , 1 d are gathered together at the basket base 20 to form an atraumatic wire basket 10 as shown in fig1 a . the end - sections 1 a , 1 b , 1 c , 1 d can be joined to a cable , shaft or coil ( not shown ). in some embodiments of the invention , the sheath 12 of the medical retrieval device is manufactured from polyimide , ptfe , composites or similar materials . in order to prevent the distal end 16 of a polyimide sheath 12 from splitting , a metal ring 180 , as illustrated in fig1 , is inserted into the lumen 14 of the distal end 16 of a polyimide sheath 12 . the metal ring 180 is flush with the end 16 of the polyimide sheath or may protrude slightly beyond the end of the sheath as illustrated in fig1 . in yet another aspect , the invention relates to a method for retrieving material from a body such as a body tract or body canal . material ( e . g ., biological or foreign ) can be retrieved from a body by using a tipless basket where at least a distal portion of the basket is defined by a shape which comprises a single unit or by using an atraumatic wire loop basket , each basket wire forming a loop with a distal atraumatic protrusion . the basket of the retrieval device has a tipless or an atraumatic distal end and thus allows the capture of material that is located in pockets or other difficult - to - access areas within the body . because the distal basket end is atraumatic , it can make intimate contact with the surface of tissue , even the walls or lining of a pocket - type area , and allows the retrieval of stones or other materials that are unrecoverable with conventional tipped baskets that can cause tissue trauma and are limited , by the existence of the protruding tip , in how close the basket can approach the tissue . a method for retrieving material from a body includes inserting a retrieval device with an atraumatic basket into the body , moving the tipless basket into the extended position , maneuvering the basket via one or more actuators on the proximal handle ( which is located outside of the body ) of the retrieval device until the material ( e . g ., stone ) is entrapped within the three - dimensional basket structure , and capturing the material within the basket by moving the basket relative to the sheath to close the basket legs around the material . with the material so gripped or held by the basket , the basket can be withdrawn from the body to remove the material from the body . before the basket is withdrawn from the body with the captured material , the material can be broken apart by , for example , laser energy or lithotripsy . mechanisms for breaking up the material before its removal from the body can be part of the retrieval device or can be separate tools / devices that are also inserted into the body and utilized at the appropriate time in the stone removal procedure . the material that can be captured with tipless baskets according to the invention includes a thrombus , embolus , foreign body , calculus , or a stone , such as a kidney stone , a ureteral stone , a urinary bladder stone , a gall bladder stone , a stone within the biliary tree , tumor , polyp or foreign body . variations , modifications , and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed . accordingly , the invention is to be defined not by the preceding illustrative description but instead by the spirit and scope of the following claims .
baskets with atraumatic distal tips allow the capture of material from difficult - to - reach areas of the body , while reducing the risk of tissue damage .