referring now to fig1 , a stone removal system 10 constructed in accordance with the principles of the present invention comprises a sweeping structure 12 and a dilating structure 14 . the sweeping structure 12 typically comprises a shaft 16 which slidably receives a rod 18 in a central passage thereof . a flat film 20 has a proximal end 22 attached to a distal end 24 of the shaft . the rod 18 extends through or over the length of the flat film 20 , typically being positioned within a lumen 26 formed in the film . usually , the rod 18 terminates in an atraumatic tip 28 , where a distal end 30 of the film is attached to the rod just proximally of the atraumatic tip 28 . as illustrated in fig2 a and 2b , the flat film 20 may be axially foreshortened and radially expanded by pulling or tensioning the rod 18 in a proximal direction relative to the shaft 16 . flat film 20 in its foreshortened , radially expanded configuration is illustrated in fig2 b . the film will usually have a width in the range from 7 mm to 15 mm when fully expanded . while a useful embodiment of the sweeping structure has been illustrated in fig1 , 2 a , and 2 b , a variety of other sweeping structures could be utilized , including in some instances balloons , expandable cages , expandable braid structures , and the like . other specific sweeping structures which employ compacted films and other lengths of material are described in copending application ser . nos . 12 / 041 , 242 ; 11 / 777 , 522 ; 10 / 888 , 886 ; and 11 / 777 , 515 , the full disclosures of which have been previously incorporated herein by reference . the dilating structure 14 is preferably configured in fig1 , to be coaxially introduced over the shaft 16 of the sweeping structure 12 . to facilitate such advancement , the proximal end of the sweeping structure will be configured to have a low profile , typically having a handle 32 having a diameter no greater than that of the shaft 16 . moreover , the maximum diameter of the handle and shaft will preferably be no greater than 2 mm , usually being no greater than 1 mm , requiring the dilating structure 14 to have a central lumen or passage which is only slightly greater than the outside diameter of the shaft 16 and handle 32 . the dilating structure 14 will typically comprise a hollow shaft 40 having a distal end 42 and a proximal end 44 . the shaft 40 will have a central passage or lumen extending its entire length in order to slidably receive a hollow rod 46 . the rod 46 extends distally of the distal end 42 and proximally of the proximal end 44 of the shaft so that a user may hold the shaft 40 and axially advance and retract the hollow rod 46 or conversely axially advance and retract the hollow shaft 40 over the hollow rod 46 using two hands . a wire element 50 is attached at a distal end 52 to a distal end 54 of the hollow rod 46 and at a proximal end 56 to the distal end 42 of the shaft 40 . in this way , the hollow rod 46 may be advanced distally relative to the shaft 40 to reduce the diameter of the wire 50 , as shown in fig3 a . by proximally drawing the rod 46 relative to the shaft 40 , as shown in fig3 b , the wire 50 can be radially expanded into a coil or loop configuration . the coil or loop , when expanded , will typically have a diameter in the range from 10 mm to 15 mm and can act to expand a ureter or other body lumen in which it has been placed . the coiled wire 50 will expand the body lumen but leave a generally open region within the body lumen to permit access therethrough , visualization therethrough , and the like . while the coiled loop embodiment of the dilating structure 14 is particularly useful , the dilating structure could comprise a variety of other expandable scaffolds or structures which can be opened or closed within the ureter or other body lumen . as shown in fig4 a and 4b , a malecot structure 60 could be attached at a distal end of the shaft 40 , where proximal end 62 of the malecot is attached to a distal end of the shaft and distal end 64 of the malecot is attached to the distal end of the rod 46 . by axially retracting the rod 46 in a proximal direction , as shown in fig4 b , the malecot is expanded , forcing individual elements 66 radially outward in order to open the body lumen in which they are placed . as a further alternative , the dilating structure could comprise a wire braid structure 70 , as illustrated in fig5 a and 5b . the wire braid structure is initially in a tubular or cylindrical configuration , as shown in fig5 a . the braid structure 70 is attached at its proximal end 72 to the distal end of the shaft 40 , while a distal end of the rod 46 is attached to the distal end 74 of the braid . by proximally retracting the rod 46 relative to the shaft 40 , as shown in fig5 b , the wire braid will be expanded providing the desired radial expansion about its midsection while ( for relatively open braids ) leaving substantial openings in an axial direction through the braid . as shown in fig5 c and 5d , a dilator structure comprising a self - expanding cone 90 can be mounted at the distal end of a dilation device 92 which further includes a hollow shaft 94 and a sheath 96 . the self - expanding cone 90 is maintained in a radially constrained configuration when the sheath 96 is advanced thereover , as illustrated in fig5 c . by retracting the sheath 96 in a proximal direction , as shown in fig5 d , the cone structure 90 will self - expand so that it has an open distal end 98 for receiving and capturing a stone ( or at least a leading edge of a stone ) in accordance with the principles of the present invention , as described in more detail with reference to fig8 below . the self - expanding cone 90 can have a variety of configurations , such as a rolled membrane , a corrugated membrane , a plurality of axial rods or elements having a mesh therebetween , or the like . most commonly , the conical structure 90 will comprise a woven nitinol wire braid including one , two , or more layers which are attached at their proximal ends to form a proximal tip at the distal end of the shaft 94 . other conical structures which can be deployed by everting or other protocols are described in parent provisional application ser . no . 61 / 118 , 802 , the full disclosure of which is incorporated herein by reference . typically , the shaft 94 and / or sheath 96 will be relatively stiff for introduction over the shaft of the sweeping device , but other flexible configurations could also find use . referring now to fig6 a through 6e , use of the stone removal system 10 for removing a kidney stone ks from the lumen l of a ureter u will be described . initially , the kidney stone ks is lodged in the lumen l in such a way that it will not naturally expel into the bladder , as illustrated in fig6 a . initially , the sweeping structure 12 is introduced into the ureter through cystoscopic access to the bladder in a conventional manner similar to that used for introducing guidewires , catheters , urinary stents , and the like . flat film 26 is typically stretched or furled so that it lies very close to the shaft to facilitate advancement past the kidney stone ks , as shown in fig6 b . usually , the flat film will be coated or otherwise modified in order to enhance its lubricity . once the sweeping structure 12 has been advanced past the kidney stone ks , the rod 18 ( fig1 ) will be retracted relative to the shaft 16 so that the film is compacted into a conformable structure immediately on the bladder side of the kidney stone , as shown in fig6 c . usually , the physician will then pull axially on the shaft 16 to see if the kidney stone ks can be easily dislodged and drawn into the bladder without damaging the ureter . if it can be , the procedure will be essentially complete and no further action will be required . in the event that the kidney stone ks cannot be removed using the sweeping structure 12 alone , the methods of the present invention will further comprise dilating the lumen l of the ureter u on the bladder side of the kidney stone , as illustrated in fig6 d . to do so , the dilating structure 14 is coaxially advanced over the shaft 16 of the sweeping structure 12 , then expanded , as shown in fig6 d . the expansion is caused when shaft 40 ( fig1 ) of the dilating structure is advanced relative to the rod 46 in order to radially expand the wire 50 , thus opening the diameter of the lumen l of the ureter u . usually , such a dilation will dislodge or mobilize the kidney stone ks , allowing the stone to be drawn toward the bladder using the sweeping structure , as illustrated in fig6 e . in some instances , a single dilation will be sufficient to allow the kidney stone to be withdrawn into the kidney , typically with the sweeping structure 12 and expanded dilating structure 14 being drawn in tandem into the bladder . optionally , the dilating structure may be serially expanded and undeployed more than once in order to provide for sequential dilations down the ureter as the sweeping structure is used to stepwise draw the kidney stone out of the ureter . in some instances , however , even dilation of the lumen l of the ureter u with the dilating structure 14 will not be sufficient to dislodge the stone ks . in such instances , the kidney stone ks can be further treated using a lithotripsy device 80 or other supplemental treatment , as illustrated in fig7 . the dilating structure may be removed to allow unfettered access to the stone , or conveniently left in place to expand the working space below the stone . conveniently , the lithotripsy device 80 tip may be introduced through the open scaffold structure defined by the coiled wire 50 . the open structure also facilitates visualization of the kidney stone . optionally , the open scaffold structure provided by the coiled wire 50 or other dilating element allows for visualization and other access to the kidney stone which would be blocked by balloons or other dilating or treatment structures . once the kidney stone ks has been fragmented , the sweeping structure 12 may be used to draw the fragments through the lumen l of the ureter u and into the bladder . referring to fig8 , after the flat film 26 has been expanded and pulled back against the kidney stone ks , as generally shown in fig6 c , dilation device 92 ( fig5 c and 5d ) may be introduced coaxially over the shaft 16 of the sweeping structure . once in position immediately adjacent to the bladder side of the stone , the sheath 96 will be retracted to allow the cone 90 to expand . the compacted flat film sweeping structure 26 may then be used to draw the kidney stone down into the expanded cone 90 through open end 98 , as shown in fig5 d . as with the prior embodiments , the cone 90 and the kidney stone can be drawn distally back toward the bladder in tandem with the sweeping structure 26 . alternatively , the expanded cone 90 may be drawn distally first , followed by drawing the sweeping structure 26 , and alternating such actions , in order to move the kidney stone ks into the bladder . while the above is a complete description of the preferred embodiments of the invention , various alternatives , modifications , and equivalents may be used . therefore , the above description should not be taken as limiting the scope of the invention which is defined by the appended claims .
a stone removal system comprises a sweeping structure and a dilating structure . the sweeping structure is deployed on a kidney side of a urinary stone in the ureter . should the sweeping structure be unable to remove the kidney stone , the dilating structure is placed on the bladder side of the kidney stone and used to dilate the lumen of the ureter . the dilated lumen allows the sweeping structure to more easily remove the kidney stone . should the kidney stone still resist removal , a lithotripsy device may be introduced through the ureter and energy directed through openings in the dilation structure to fragment the stone .