Abstract:
A medical instrument adapted for disposition a relative to an orifice defined in a body wall or for disposition in a passage in a body is provided. The medical instrument includes an elongate tube portion having a handle disposed at one end thereof, and an expandable section disposed near the other end thereof. The expansion member is expandable to form a seal between the expansion member and a surface of the body wall orifice or the body passage around substantially an entire circumference of the expansion member.

Description:
This is a continuation, of application Ser. No. 07/873,705, filed Apr. 22, 1992 now abandoned, which is a continuation of Ser. No. 07/574,454, filed Aug. 29, 1990 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to catheters adapted for sealing and/or occluding cavities and vessels, tubes or other body conduits. 
     2. Description of the Prior Art 
     Patients complaining of lower abdominal pain or hematuria (blood in the urine) are often suspect for blockages in the ureter, a relative long, narrow tube which extends from each of the kidneys to the bladder. These blockages may result from kidney stones, tumors, strictures or other obstructions. 
     The most noninvasive way for determining whether there is a blockage in the ureter is to perform an IV pyleogram. This procedure calls for the intravenous injection of a contrast media or dye into the arm of the patient. This dye eventually collects in the kidneys and passes into the ureters. By using known X-ray fluoroscopic methods, the path of the d ye can be determined. If there is a blockage in the ureter, the path of the dye stops at this blockage providing a contrast in the X-ray which shows the location of the obstruction. If there is more than one obstruction, the dye will be blocked at the first obstruction and may not flow beyond that point. Additional blockages further down the ureter would not be apparent using this intravenous procedure. 
     Under these conditions, it is sometimes desirable to perform a retrograde procedure which requires that dye be injected at the lower end of the ureter and forced upwardly from the bladder toward the kidney. Although this procedure is quite effective in providing a fluoroscopic view of the lower regions of the ureter, it is somewhat more invasive than the intravenous procedure in that it calls for introduction of an injection catheter through the urethra, into the bladder, and through the ureter orifice into the ureter. 
     In order to provide suitable visualization of this region, the injection catheter is typically introduced through the working channel of a cystoscope. After the catheter has been positioned, the dye is introduced at the lower end of the ureter and forced upwardly against the force of gravity toward the kidneys. This can present a problem as the dye tends to flow downwardly into the bladder rather than upwardly toward the kidney. In the past, some injection catheters have been provided with enlarged silicone bulbs at their distal ends. These bulbs have been held against the ureter orifice in order to seal the orifice against the downward flow of the dye. 
     The sealing bulbs have required a size such as fourteen French (14F), a diameter which is sufficient to extend across the normal width of a ureter orifice. While rigid cystoscopes have provided working channels of approximately 14F, the much preferred flexible cystoscopes have working channels of only 7F or 8F. In order to use the injection catheters with the flexible cystoscopes, the catheters have required frontloading, that is they have been introduced through the distal end of the cystoscope toward the proximal end of the cystoscope. After the dye has been injected it is desirable to remove the injection catheter. However, with the relative large seating bulb it has been impossible to withdraw the catheter through the relatviely small working channel of the cystoscope. As a consequence, in order to remove these injection catheters, it had been necessary to remove the entire cystoscope. 
     What is required is an injection catheter which can be introduced through the narrow channel of a flexible cystoscope, subsequently expanded to block the ureter orifice, and ultimately contracted to permit removal while the cystoscope is left in place. 
     Catheters of the past have included balloon as well as mesh structures which are expandable from a low profile state. However, the shape of these devices in their expanded state has tended to be round or spherical in cross-section so they have not provided suitable shapes for occluding an orifice. In the case of the mesh structures, the catheters have been adapted solely for embolectomy procedures wherein the expanded mesh structure is used to push blood clots through the vessels. Typically these catheters have not been suitable for injection purposes because the mesh has been porous. 
     SUMMARY OF THE INVENTION 
     These problems associated with the prior art have been overcome with the present invention which provides a catheter having a tube means adapted for insertion through a body orifice to dispense an injectate into a body conduit or cavity on the other side of the orifice. A mesh tube is provided proximally of the injection port at the end of the catheter tube means. In a particular embodiment this mesh is expandable from approximately 5F to 14F and presents a generally conical surface at its distal end. A suitable silicone can be applied to seal the mesh so that the injectate can flow through the mesh to the injection port at the end of the catheter. 
     With the injection port positioned in the ureter, the catheter can be moved forward to bring the expanded mesh into contact with the ureter orifice. In this location the expanded mesh forms a seal with the walls of the ureter near the bladder. The seal prevents the injected dye from moving downwardly so that it tends to travel upwardly toward the kidneys. 
     In one aspect of the invention, the mesh tube has a distal end and a proximal end, and means is provided for the relative movement of the distal end toward the proximal end. This causes the intermediate regions of the tube to expand outwardly thereby providing the tube with an increased diameter and a preferred conical shape. Disposition of the silicone on the tubular mesh can facilitate various other shapes for the mesh in its expanded state. 
     In a preferred method for making the catheter, a section of the mesh tubing is disposed axially on a mandrel and its ends are bonded to inhibit fraying. The distal end of an injection catheter is moved onto the mandrel in abutting relationship with the mesh subassembly. A tubing sleeve can then be glued over the butt joint between the catheter and the tube. With the mandrel still in place, a coating of silicone can be applied over the mesh to seal the expandable structure. The mandrel is ultimately removed to clear the injection channel which extends through the catheter and the mesh tube. 
     Finally a wire, or other tension means, is introduced down the injection channel and crimped around the distal end of the mesh tube. In operation, this wire is pulled proximally within the catheter to draw the distal end of the mesh tube toward the proximal end of the mesh tube. This provides the desired expansion and shape for sealing/occluding an orifice, tube, or cavity. 
     These and other advantages associated with the instant invention would be more apparent with a discussion of preferred embodiments of the concept in reference to the associated drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial illustration of the kidneys, the bladder, and the ureters which extend therebetween; 
     FIG. 2 is an enlarged side elevation view of the cystoscope and an catheter associated with the present invention, operatively disposed in the bladder to perform a retrograde pylogram; 
     FIG. 3 is a perspective view of the catheter illustrating an expandable mesh section in a contracted state; 
     FIG. 4 is a perspective view similar to FIG. 3 illustrating the expandable mesh section in an expanded state. 
     FIG. 5 is a cross-sectional view of the catheter illustrating the expandable mesh section at the distal end of the catheter; 
     FIG. 6 illustrates a section of mesh disposed on a mandrel in the initial step of a preferred method for manufacturing the catheter; 
     FIG. 7 is a side view of the mesh tube and mandrel of FIG. 6 with adhesive applied to the ends of the mesh tube to form a mesh tube subassembly; 
     FIG. 8 illustrates a side elevation view of a catheter tube received over the mandrel forming a butt joint with the mesh tube subassembly; and 
     FIG. 9 is a further embodiment of the present invention including an expandable section formed from silicone and including a living hinge. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A human body is illustrated in FIG.  1  and designated by the reference numeral  10 . A pair of kidneys  12  and  14  are disposed in the lumbar region of the body  10  and function to filter the blood, excreting the end-products of body metabolism in the form of urine. This urine is introduced through a pair of ureters  15  and  16  which are associated with the kidneys  12  and  14 , respectively. From the ureters  15 ,  16  the urine flows into a common bladder  18  through respective ureter orifices  21  and  23 . The urine is emptied from the body through a urethra  27 . 
     In the following description, reference will be made primarily to the kidney  14 , ureter  16 , and orifice  23  on the left side of the body  10 . However, the comments may apply equally to the kidney  12 , ureter  15 , and orifice  21  on the right side of the body  10 . 
     In a procedure involving a retrograde ureter pylogram, a cystoscope  30  is introduced through the urethra  27  and into the bladder  18 . The cystoscope  30  provides means for visualizing the interior region of a body conduit or cavity from a location at the proximal end of the cystoscope. Fiberoptics provide light at the distal end of the cystoscope and communicate images back to an eyepiece (not shown) at the proximal end of the cystoscope  30 . 
     Of particular interest in the cystoscope  30  is a working channel  34  which extends through the cystoscope  30 . Although this working channel  34  is quite narrow, approximately 7F or 8F, it nevertheless is configured to receive various instruments such as brushes, clips, biopsy devices and stone removal baskets. In accordance with the present procedure, an injection catheter  36  is introduced through the working channel  34  in the cystoscope  30 . 
     The catheter  36  is perhaps best illustrated in FIGS. 3 and  4 . It can include a tube means comprising an elongate flexible tube  38  having a handle  41  disposed at its proximal end, and an expandable section  43  disposed near its distal end. An injection channel  45  extends from a Leur hub  47  at the handle  41 , through the tube  38  and the expandable section  43 , to exit the catheter  36  at an injection port  50 . 
     In a procedure involving a retrograde polyogram, the flexible tube  38  of the catheter  36  is introduced through the working channel  34  of the cystoscope  30 , and the distal port  50  of the catheter is directed through the ureter orifice  23  into the ureter  16 . With the injection port  50  thus positioned, the dye can be injected through the Leur hub  47  and the channel  45  to exit the injection port  50  into the ureter  16 . 
     Of particular interest to the present invention is the expandable section  43  of the catheter  36 . It is this section  43  which can be brought into sealing engagement with the ureter orifice  23  to inhibit a flow of the injected dye back into the bladder  18 . In FIG. 3, this expandable section  43  is illustrated to have a low profile with a diameter which is substantially equivalent to that of the flexible tube  38 . This low profile is particularly desirable when the catheter  36  is being introduced through the narrow working channel  34  of the cystoscope  30 . 
     Operation of the catheter  36  expands the diameter of the section  43  as illustrated in FIG.  4 . In the case of an embodiment adapted for sealing the ureter orifice  23 , it is particularly desirable that the section  43  expand in the shape of cone shown generally at  52  with the apex  54  of the cone  52  facing distally of the catheter  36 . This shape provides a generally concave surface  56  which faces the orifice  23 . In another aspect of the invention, the surface  56  of the cone  52  progresses radially outwardly with progressive positions from the apex  54  proximally to the base of the cone  52 . 
     Referring to the embodiment of FIG. 5, the section  43  is illustrated to include an expandable tube  58  having a distal end  61  and a proximal end  63 . Each of the ends  61  and  63  are provided with an adhesive coating  65  and  67  respectively. These coatings prevent the mesh tube  58  from fraying or unraveling. In a preferred embodiment the proximal end  63  of the tube  58  and the distal end of the catheter tube  38  form a butt joint  72 . This joint  72  can be covered with a sleeve  74  which is attached by a suitable adhesive to the catheter tube  38  and the expandable tube  58 . 
     In the expandable section  43 , the tube  58  is representative of any tubular material which has sufficient flexibility and elasticity to permit the ends of the tubes  61 ,  63  to be moved axially inwardly (toward each other) thereby causing the central regions of the tube  58  to expand radially outwardly. This of course increases the diameter of the tube  58 . 
     These characteristics are particularly apparent when the tube  58  is made from mesh as illustrated in FIG.  5 . In this embodiment, means for drawing the distal end  61  toward the proximal end  63  is provided in the form of a wire  76  which extends from the proximal end of the catheter  36 , through the channel  45  and the expandable tube  58 , to exit the catheter through the injection port  50 . Beyond the port  50 , the wire  76  can be bent back on itself around the distal end  61  of the expandable tube  58 . In a preferred embodiment, this end  78  of the wire  76  is held in place by a suitable adhesive  81 . 
     In other embodiments it may be desirable to attach the wire  76  at a more proximate position. In general, the wire  76  can accomplish its function if its distal end is attached to the catheter  36  at any location which is distal to the end  61  of the expandable tube  58 . 
     The wire  76  is representative of any tension means having properties for extending through a first end of a tube and engaging a second end of the tube to draw the second end toward the first end of the tube. The wire also functions as a compression means having properties for extending through the first end of the tube and engaging the second end of the tube to push the second end away from the first end of the tube. 
     At the proximal end of the catheter  36 , the wire  76  can be attached to a thumb slide  83  which is engagable by the thumb of the user. In a preferred embodiment, the slide  83  is movable on the handle  41  from a proximal position illustrated in FIG. 3 to a distal position illustrated in FIG.  4 . 
     With the wire  76  connected to the distal end  61  of the expandable tube  58 , movement of the thumb slide  83  from its distal position to its proximal position will draw the distal end  61  of the expandable tube  58  toward the proximal end  63 . Those regions of the tube  58  which are disposed between the ends  61  and  63  are forced to expand outwardly thereby increasing the diameter of the tube  58 . 
     Particularly in those embodiments relying upon the integrity of the channel  45 , it is desirable that the expandable tube  58  have solid walls so that the channel  45  extends through the tube  58  to the injection port  50 . When the expandable tube  58  is formed from a mesh material, it is desirable to provide the mesh with a coating  83  of a solid material such as silicone. 
     The expandable tube  58  can be formed from materials other than mesh and can even be configured to provide the tube  58  in its expanded state with shapes other than that of the cone  52 . For example, the expandable tube  58  may be formed from a silicone tube  58   a  having a distal end  61   a  and a proximal end  63   a.  As illustrated in FIG. 9, this tube  58   a  can be provided with an exterior circumferential cut out  85  to form an area of weakness between the ends  61   a  and  63   a.  Then when the ends  61   a,    63   a  are brought into proximity, the cut out  85  functions as a living hinge to facilitate the radial expansion and conical shape of the tube  58   a.    
     In a preferred method for manufacturing the catheter  38 , the subassembly  70  is initially formed by placing a section of the mesh tubing  58  over a mandrel  87  as illustrated in FIG.  6 . In this method the mandrel  87  is coated with Teflon® and provided with a diameter such as 0.020 inches. The mesh tube  58  can be formed from 5 mil. polyester fibers and provided with an inside diameter not less than the diameter of the mandrel  87 . The length of the tube  58  is approximately ¾″j in this embodiment. 
     This combination can be heated in an oven for a period of 15 to 20 minutes at a temperature of 150 degrees F. in order to heat set the polyester mesh. 
     The coatings  65  and  67  can be formed by coating the distal and proximal ends  61 ,  63  respectively with a suitable UV adhesive such as that manufactured by Loctite and sold under the trademark Improv®. At the distal end  61 , the coating  65  preferably has an axial dimension less than 0.060 inches. The coating  67  at the proximal end of the mesh tube  58  does not exceed 0.200 inches. The ends of the mesh tube  58  can then be cut so that the subassembly  70  has a length of about 0.550 inches. The adhesive coatings  65  and  67  can be cured by setting the subassembly  70  under a light source for approximately 40 seconds or until the adhesive has a glazed appearance. The outer diameter of the subassembly  70  does not exceed 0.050 inches in this preferred embodiment. 
     The tube  38  of the catheter  36  can be formed from polyvinylchloride tubing having an outside diameter such as 0.056 inches and cut to a length such as 2 feet. As illustrated in FIG. 8, the tube  38  can be guided onto the mandrel  87  and moved into abutting relationship at the proximal end  63  of the subassembly  70 . This forms the butt joint  72  with the mandrel  87  still in place. The sleeve  74  can be provided in the form of a polyamide tubing having an outside diameter such as 0.059 inches and a length such as 0.035 inches. The sleeve  74  can be positioned over the butt joint  72  and bonded with a suitable adhesive, such as cyaroacrylate, to the tube  38  and the subassembly  70 . 
     The silicone coating  83  which fills the interstitices of the mesh tube  58 , can be formed by brushing a silicone dispersion such as acetoxy onto the mesh and curing the dispersion in an oven for approximately 30 minutes at a temperature such as 160 degrees F. After this curing step, the catheter  36  can be cooled and the mandrel  87  removed from the channel  45 . 
     At this point, the wire  76  can be introduced into the channel  45  with its distal end extending beyond the injection port  50 . This wire in a preferred embodiment had a diameter of 0.009 inches and is formed from stainless steel. The distal end of the wire can be bent over the coating  65  at the distal end of the flexible tube  58  and fixed with the adhesive  81 . At the proximal end of the catheter  36 , the wire  76  is attached to the thumb slide  83  as previously discussed. 
     In particular embodiments of the catheter  36 , the silicone coating  87 , or the silicone tube  58   a  in the case of the FIG. 9 embodiment, can be scored or otherwise provided with the cut out  85  to facilitate a particularly desirable shape for the expandable tube  58  in its expanded state. 
     Although the invention has been described with reference to specific embodiments and preferred steps in a method of manufacture, it will be apparent to those skilled in the art that the invention can be otherwise embodied and the catheter can be otherwise constructed. These variations are all deemed to be part of the broad concept so that the scope of the invention should be ascertained only with reference to the following claims.