Abstract:
A device for circulating fluid to a target site within a living body, comprises a longitudinal member including an inlet lumen supplying fluid to the target site and a return lumen withdrawing fluid from the target site, the return lumen surrounding the inlet lumen and a screen coupled to a distal end of the longitudinal member, the screen including a plurality of openings extending therethrough from a radially inner surface forming a radially outer wall of a distal portion of the return lumen to an outer surface thereof.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the priority to the U.S. Provisional Application Ser. No. 61/100,972, entitled “Fluid Recirculation Debris Handling System” filed on Sep. 29, 2008. The specification of the above-identified application is incorporated herewith by reference. 
     
    
     BACKGROUND 
       [0002]    Endometrial ablation is a procedure conducted to reduce or eliminate excessive uterine bleeding by ablating the innermost lining of the uterus, known as the endometrium. One method of ablating the endometrium is by using the HydroThermAblator® System (HTA) which circulates heated fluid in the uterus. A sheath is inserted into the uterus via the cervix to introduce and circulate the heated fluid and to maintain a target ablation temperature through the uterus. An ablation sheath generally includes an inlet lumen via which the heated fluid is introduced into the uterus and a return lumen via which the fluid may be returned, heated and circulated back into the body to maintain the target ablation temperature. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is directed to a device for circulating fluid to a target site within a living body, comprising a longitudinal member including an inlet lumen supplying fluid to the target site and a return lumen withdrawing fluid from the target site, the return lumen surrounding the inlet lumen and a screen coupled to a distal end of the longitudinal member, the screen including a plurality of openings extending therethrough from a radially inner surface forming a radially outer wall of a distal portion of the return lumen to an outer surface thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  shows a perspective view of a device according to a first exemplary embodiment of the present invention; 
           [0005]      FIG. 2  shows a longitudinal cross-sectional view of the device of  FIG. 1 ; 
           [0006]      FIG. 3  shows a lateral cross-sectional view of the device of  FIG. 1 ; 
           [0007]      FIG. 4  shows a perspective view of a distal end of the device of  FIG. 1 ; 
           [0008]      FIG. 5  shows a longitudinal cross-sectional view of a device according to a second exemplary embodiment of the present invention; 
           [0009]      FIG. 6  shows a perspective view of a distal end of the device shown in  FIG. 5 ; 
           [0010]      FIG. 7  shows a perspective view of a device according to a third exemplary embodiment of the present invention; and 
           [0011]      FIG. 8  shows a perspective view of a device according to a fourth exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The present invention, which may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals, relates to devices for treating an endometrial lining of a uterus. In particular, the present invention relates to devices for circulating heated fluid through hollow organs such as the uterus to treat tissue therein (e.g., the endometrium). As the endometrial lining is ablated, debris is often generated in the uterus. Exemplary embodiments of the present invention provide a device for circulating fluid, including a distal tip that prevents the debris from returning into and occluding the device, thereby preventing any impedance of the circulatory flow of the fluid. As would be understood by those skilled in the art, although this invention is described in conjunction with the ablation of the endometrium, the invention may be used in conjunction with the treatment of the tissue of any hollow organ. 
         [0013]    As shown in  FIGS. 1-4 , a device  100 , according to an exemplary embodiment of the invention comprises a longitudinal member  102  and a screen  104  located at a distal end  106  thereof. The device  100  may be sized and shaped to be inserted into an internal space of a living body, in particular, to be inserted into a uterus via a cervix. In a preferred embodiment, an outer diameter of the device  100  may range from approximately 7.0 mm to 7.7 mm to ensure ease of insertion of the device  100  into the uterus via the cervix. As shown in  FIGS. 2-3 , the longitudinal member  102  comprises a first sleeve  108  housed within a second sleeve  110  which is housed within a third sleeve  112 . The sleeves  108 ,  110 ,  112  in this example are co-axial. An inlet lumen  114  within the first sleeve  108  extends from a proximal end (not shown) connectable to a supply of ablation fluid so that, when in a desired position within the body, fluid introduced thereinto flows into the uterus via a distal opening  122 . The first sleeve  108  may be formed of a metal such as, for example, stainless steel. It will be understood by those of skill in the art that the metal will provide mechanical stability and stiffness of the longitudinal member  102 , while providing an optimal cross-sectional fluid flow area. A hysteroscope  116  may also be introduced into the body via the lumen  114  with fluid continuing to flow in an annular space between the hysteroscope and the wall of the lumen  114  as shown by the arrows in  FIG. 2 . The metal material of the first sleeve  108  guides a sometimes sharp tip of the hysteroscope  116  without catching on or damaging the material of the first sleeve  108 . 
         [0014]    A return lumen  118  formed in an annular space between an outer surface of the first sleeve  108  and an inner surface of the second sleeve  110  opens to the outside of the device  100  via a plurality of slots  130  extending through a screen  104  which is mounted over the distal end  106 . The screen includes an opening  126  through which fluid from the distal opening  122  of the lumen  114  passes into the uterus. Negative pressure may be applied to the return lumen  118  to draw fluid from the region surrounding the distal end  106  through the screen  104  into the return lumen  118  for withdrawal from the body. In an alternative embodiment, a positive pressure may be applied through the lumen  114  elevating the pressure within the uterus and forcing fluid out of the uterus through the screen  104  and into the distal end  124  of the return lumen  118 . After removal from the body, the fluid from the return lumen  118  may be filtered, reheated and returned to the uterus via the lumen  114  or may be withdrawn from circulation and replaced by fresh fluid as desired. The screen  104  facilitates the return of this fluid by providing an initial filtering of the fluid to reduce particles suspended therein. In one embodiment, an area of the return lumen  118  may be approximately 0.009 sq. inches. 
         [0015]    An insulative gap  120  is formed in an annular space between an inner surface of the third sleeve  112  and an outer surface of the second sleeve  110 . The insulative gap  120  may be filled with air to minimize heat transfer from the fluids flowing through the inlet lumen  114  and the fluid return lumen  118  to non-targeted tissue adjacent to the device  100  to prevent burns and/or other damage to this surrounding tissue. It will be understood by those of skill in the art that the second sleeve  110 , which forms part of insulative gap  120 , may be formed of a plastic or other thermally insulative material. As would be understood by those skilled in the art, one or more additional layers of insulation may be provided if desired. 
         [0016]    As shown in  FIG. 2 , the first sleeve  108  extends distally past the second sleeve  110  such that an opening  122  of the inlet lumen  114  is distally beyond a distal opening  124  of the return lumen  118 . Thus, fluid entering the return lumen  118  will do so via the screen  104  at locations proximal of the distal opening  122  of the lumen  114 . it will be understood by those of skill in the art that a staggered flow pattern is established such that all of the fluid flow through the inlet lumen  114  is forced into the uterus and back to the return lumen  118 . This staggered flow pattern creates greater turbulence within the uterus and allows for better heat distribution through the uterus. The screen  104  is coupled to the distal end  106  of the device such that a distal end  126  of the screen  104  is substantially aligned with the opening  122  of the inlet lumen  114  formed by the first sleeve  108 . The screen  104  may be coupled to the longitudinal member  102  by any number of coupling means. For example, the screen  104  may include a male mating component  132  that is receivable within the insulative gap  120  between the second and third sleeves  110 ,  112 , which acts as a female mating component. The male mating component  132  and the female mating component of the insulation gap  120  may be locked together. 
         [0017]    As shown in  FIG. 4 , the screen  104  includes an open distal end  126  substantially similar in diameter to a diameter of the inlet lumen  114 . The screen  104  is substantially dome-shaped with an outer surface of the screen  104  curved and a proximal end  128  of the screen  104  shaped to be received within the insulative gap  120  between the inner surface of the third sleeve  112  and the outer surface of the second sleeve  110 . During endometrial ablation procedures, the cervix is generally dilated to approximately 8 mm to reduce the force required to insert an HTA device therethrough. As would be understood by those skilled in the art, the dome shape of the screen  104  and the tapered distal end  126  reduce the force required to insert the device  100  into the body possibly allowing the insertion of the device  100  with a lesser amount of dilation reducing trauma to the surrounding tissue. Additionally, the dome shape of the screen  104  may increase the structural stability of the screen  104 , as loads during insertion are distributed substantially evenly around a circumference of an outer surface of the screen  104 . It will be understood by those of skill in the art, however, that although the screen  104  is shown to be dome-shaped, the screen  104  may take a variety of shapes. These shapes will generally include a taper with the distal opening  126  being smaller than the proximal end  128  to facilitate insertion. For example, the screen  104  may be hemispherically shaped to provide an optimal level of strength. In an alternative embodiment, the screen  104  may have a truncated conical shape to facilitate insertion into the cervical cavity. In yet another embodiment, the screen  104  may be have a substantially parabolic dome shape such that the screen  104  may retain a level of strength, while still facilitating insertion into the cervical cavity. 
         [0018]    The distal end  126  of the screen  104  extends from a distal end  138  of the first sleeve  108  proximally past a distal end  140  of the second sleeve  110  such that return fluid must first pass through the screen  104  to access the opening  124  of the return lumen  118 . The screen  104  includes a plurality of slots  130  distributed around at least a portion of a circumference thereof with each slot extending along at least a portion of the length of the screen  104  (i.e., parallel to a longitudinal axis of the device  100 ) and passing from an opening in an outer surface  134  through an inner surface  136  of the screen  104 . A width of each slot  130  may be made smaller than a width of the return lumen  118  to ensure that any debris that is able to pass through the screen  104 , is too small to occlude the return lumen  118 . As the screen  104  extends distally past the distal end of the second sleeve  110 , the slots  130  increase the total area available for fluid to enter the return lumen  118  without substantially affecting the pressure in the return lumen  118 . In a preferred embodiment, the aggregate area of the slots  130  is approximately five times the cross-sectional area of the return lumen  118 . For example, if the cross-sectional area of the return lumen  118  is approximately 0.009 sq. inches, the aggregate area of the slots  130  may be approximately 0.05 sq. inches. This allows the pressure and the flow characteristics of the return lumen  118  to remain acceptable even if 80% or more of the screen  104  were occluded with debris. Additionally as will be understood by those of skill in the art, the distribution of the total area of the slots  130  over the surface of the screen  104  reduces the velocity and pressure with which fluid first contacts the longitudinal member  102  reducing the likelihood of large debris becoming embedded within the slots  130 . 
         [0019]    As shown in  FIGS. 5-6 , a device  200  according to another embodiment of the present invention comprises a longitudinal member  202  and a screen  204  coupled to a distal end  206  thereof. Similarly to the device  100 , the longitudinal member  202  includes a first sleeve  208 , a second sleeve  210 , and a third sleeve  212 , each of which share a longitudinal axis. In the device  200 , the first sleeve  208  extends slightly distally of the second and third sleeves,  210  and  212 , respectively, with an outer wall of a distal portion of the return lumen  218  being formed by an inner surface of a mating component  232  of the screen  204 . The mating component  232  is received within an annular space  220  between the outer surface of the second sleeve  210  and an inner surface of the third sleeve  212  and extends distally to a screen portion  234  of the screen  204 . As described above, this annular space  220  serves as an insulation gap minimizing heat transfer between the heated fluids in the longitudinal member  202  and surrounding tissue. When mated to the longitudinal member  202 , the mating component  232  ends at a point substantially aligned with the distal end  238  of the first sleeve  208  so that the return lumen  218  terminates at a point aligned with the distal opening  222  of the working channel  214 . As shown in  FIG. 5 , the working channel  214  is sized so that, when a hysteroscope  216  is inserted therein, an annular space surrounding the hysteroscope  216  functions as an inlet lumen  217  for the device  200 . 
         [0020]    The screen  204  may be substantially similar to the screen  104 . A distal opening  226  of the screen  204 , however, may be smaller than the distal opening  126  and the mating component  232  of the screen  204  may mate with the longitudinal member  202  such that a proximal end  228  of the screen portion  234  substantially aligns with the distal end  238  of the first sleeve  208 . The screen  204  covers the entire distal end  206  of the longitudinal member  202  to prevent debris from entering the debris lumen  218 . It will be understood by those of skill in the art, that the aggregate area of the slots  230  is preferably substantially greater than an aggregate cross-sectional area of the inlet and return lumens  217 ,  218 , respectively, so that the flow characteristics of these lumens may remain unchanged even when a significant portion of the area of the slots  230  is blocked by debris removed from the return fluid. 
         [0021]    As shown in  FIG. 6 , the screen  204  includes a plurality of slots  230  substantially similar to the slots  130  of screen  104 . The slots  230  extend around at least a portion of a circumference of the screen  230 , and each slot  230  may extend along at least a portion of a length of the screen  204 . A width of each of the slots  230  is preferably smaller than a width of the opening  224  of the return lumen  218  so that any debris that passes through the screen  204  via the slots  230  will be too small to occlude the return lumen  218 . 
         [0022]    As shown in  FIG. 7 , a device  300 , according to an alternate embodiment of the present invention, comprises a longitudinal member  302  and a screen  304  coupled to a distal end  306  thereof. The longitudinal member  304  may be substantially similar to either of the longitudinal members  102  and  202 , respectively, described above in regard to devices  100 ,  200 . The screen  304  may also be substantially similar to the screens  104  and  204 , including an open distal end  326  that is smaller in diameter than a proximal end  328  of the screen  304 . It will be understood by those of skill in the art that although the screen  304  is shown to be substantially conically shaped, the screen  304  may take a variety of shapes so long as the distal opening  326  is smaller than the proximal end  328 . For example, the screen  304  may be dome-shaped. 
         [0023]    The screen  304  further includes a plurality of holes  330  distributed around at least a portion of a circumference and a portion of a length of the screen  404 . Each of the holes  330  extends from an outer surface  334  to an inner surface  336  such that return fluid must pass through the holes  330  to access a return lumen (not shown). Each of the holes  330  may be smaller in size than an opening of the return lumen to ensure that any debris that is able to pass through the holes  330  are too small to occlude the return lumen. It will be understood by those of skill in the art, that the aggregate area of the holes  330  is preferably substantially greater than an aggregate cross-sectional area of the inlet and return lumens of the longitudinal member  302  so that the flow characteristics of these lumens may remain unchanged even when a significant portion of the area of the holes  330  is blocked by debris removed from the return fluid. 
         [0024]    As shown in  FIG. 8 , a device  400 , according to an alternate embodiment of the present invention, comprises a longitudinal member  402  and a screen  404  attached to a distal end  406  thereof. The longitudinal member  402  may be substantially similar to either of the longitudinal members  102  and  202 , respectively, described above in regard to devices  100 ,  200 . The screen  404  may also be substantially similar to the screens  104 ,  204  and  304 , including an open distal end  426  that is smaller in diameter than a proximal end  428  of the screen  404 . It will be understood by those of skill in the art that although the screen  404  is shown to be substantially conically shaped, the screen  404  may take a variety of shapes. As indicated above, tapered shapes may be desired to facilitate insertion. For example, the screen  404  may be dome-shaped, conic, etc. 
         [0025]    The screen  404  further includes a plurality of slots  430  distributed along at least a portion of a length of the screen  404 , each of the slots  430  extending around at least a portion of a circumference of the screen  404 . Each of the slots  430  extends from an outer surface  434  to an inner surface  436  such that return fluid must pass through the slots  430  to access a return lumen (not shown). Each of the slots  430  may be smaller in width than opening of the return lumen to ensure that any debris that is able to pass through the slots  430  is too small to occlude the return lumen. It will be understood by those of skill in the art, that the aggregate area of the holes  430  is preferably substantially greater than an aggregate cross-sectional area of the inlet and/or return lumens of the longitudinal member  402  so that the flow characteristics of these lumens may remain unchanged even when a significant portion of the area of the slots  430  is blocked by debris removed from the return fluid. 
         [0026]    It will be understood by those of skill in the art that various modifications and variations can be made in the structure and the methodology of the present invention without departing from the sprit or the scope of the invention. Thus, it is intended that the present invention cover the modifications and the variations of this invention provided that they come within the scope of the appended claims and their equivalents.