TECHNICAL FIELDThe invention relates to minimally invasive medical devices and procedures, and, more particularly, to devices and procedures for removing kidney stones.[0001]
BACKGROUND INFORMATIONVarious methods exist to remove calculi from body cavities. Calculi, such as those formed in a gall bladder or kidney, can cause significant problems for a patient. For example, ureteral constriction and blockage can cause hydronepherosis, a condition characterized by the damming of urine in the kidneys. A frequent blockage site is the junction of the ureter and the renal pelvis. Acquired blockages are most commonly caused by kidney stones that root themselves in the ureteral lumen wall.[0002]
Often, kidney stone removal is performed using stone retrieval devices based on wire baskets, lithotrypsies, pharmaceutical therapeutics or surgery. For example, a cystoscope can be introduced into the ureter to remove an embedded stone. The cytoscope typically includes a wire basket disposed at the distal end. The stone is trapped in the basket, and the cystoscope and trapped stone are then removed from the body.[0003]
Existing methods have several deficiencies. These treatments can be difficult to perform, can lead to severe adverse events, and can entail high cost. For example, a retrieval basket can have difficulty trapping calculi of some sizes or shapes. Body tissues can be damaged while spreading the basket and attempting to grasp a stone. A basket may have difficulty grasping a stone that is embedded in a wall of a body lumen. Further, the size of the basket/stone combination may create difficulty in removing the apparatus from the body. Use of ultrasound or solvents can damage body tissues in the vicinity of the stone.[0004]
SUMMARY OF THE INVENTIONMethods and devices of the invention enable removal of objects from body lumens with relatively low cost and low incidence of adverse effects. Generally, methods and devices according to invention involve the use of a fluid dispensed into a body lumen to dislodge and/or propel an object in the body lumen. The body lumen can be distended to assist the release of an embedded object.[0005]
For example, a kidney stone can be propelled from a ureter into a bladder, without recourse to chemicals, drugs, wire baskets, lithotrypsy or surgery. The invention thus provides an out-patient procedure, that can be performed under a local anesthetic. Some procedures of the invention provide a less painful treatment than many conventional procedures.[0006]
Accordingly, in one aspect, the invention features a method for removing an object from a body lumen. The method includes dispensing fluid into the body lumen, and causing the dispensed fluid to propel the object along the body lumen. For example, the object can be a kidney stone lodged in a ureter, and the dispensed fluid propels the stone along the ureter, towards the bladder.[0007]
The method can include positioning a fluid dispenser in the body lumen to dispense the fluid. The flow of the dispensed fluid can be impeded in at least one direction through the body lumen. For example, when a kidney stone is being removed from a ureter, the flow of the dispensed fluid can be impeded through the ureter towards the kidney.[0008]
In one embodiment, a predetermined quantity of the dispensed fluid is confined within a portion of the body lumen. The portion of the body lumen contains the object. The fluid can be confined by impeding the flow of the fluid at a distal end and at a proximal end of the portion of the body lumen, for example, with clamps or expanded balloons. The predetermined quantity of fluid can be released through the proximal end of the portion of the body lumen to propel the object past the proximal end of the portion of the body lumen.[0009]
In some embodiments, the distance between the proximal end and the distal end of the portion of the body lumen is decreased to cause an increase in a fluid turbulence within the body lumen when the fluid is released. Dispensing and releasing predetermined quantities of fluid can be repeated to dislodge and/or propel the object in lumen.[0010]
The portion of the body lumen can be allowed to expand while confining the dispensed fluid, to ease the movement of the object through the body lumen.[0011]
The fluid can be dispensed at a predetermined pressure level, or dispensed until a predetermined pressure level is attained. The pressure of the dispensed fluid can be varied to dislodge the object from a wall of the body lumen.[0012]
The method can further include positioning a distal balloon within the body lumen at a distal end of a portion of the body lumen that contains the object, and positioning a proximal balloon within the body lumen at the proximal end of the portion of the body lumen. The dispensed fluid can then propel the object by pressurizing the proximal balloon to a lower pressure than a pressure of the distal balloon to permit a flow of the fluid past the proximal balloon.[0013]
In another embodiment, the pressure of the proximal balloon is decreased after the predetermined quantity of fluid is dispensed. The quantity of fluid can then flow past the proximal end of the portion of the body lumen, to remove the object.[0014]
In general, in another aspect, the invention features a device for removing an object from a body lumen. The device includes a fluid dispenser for dispensing a fluid into the body lumen, and a pump in fluid communication with the fluid dispenser, the pump comprising a fluid volume controller configured to provide a sufficient quantity of fluid to cause the object to move through the body lumen. The device includes a distal expansible member, for example, a balloon, in mechanical communication with the fluid dispenser to stabilize the location of the fluid dispenser within the body lumen when the distal expansible member is in an expanded state.[0015]
The fluid dispenser defines an aperture through which the fluid is dispensed into the body lumen. Also, a proximal expansible member can be in mechanical communication with the fluid dispenser, with the aperture disposed between the distal and proximal expansible members. Expansion and contraction of the proximal expansible member can then control a flow of the fluid past the proximal expansible member.[0016]
The distal expansible member can include a balloon that is inflated to a greater pressure than the pressure of the proximal expansible member, to permit the fluid to flow past the proximal expansible member.[0017]
The device can include a pump to pump the fluid to the fluid dispenser. The pump can include a non-positive displacement pump having a preset pressure limit, or a positive displacement pump having a relief valve with a preset pressure limit. The pump can be built into a handle. The pump can also include a pressure controller configured to provide a sufficient pressure to displace the object in the body lumen.[0018]
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.[0019]
BRIEF DESCRIPTION OF THE DRAWINGSIn the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.[0020]
FIG. 1 is a cross-sectional view of a body lumen containing a blockage, which illustrates a method of removing an object from the body lumen, according to general principles of the invention.[0021]
FIG. 2 is a cross-sectional view of an embodiment of a device for removing an object from a body lumen, with the device positioned in a body lumen that has an embedded object.[0022]
FIG. 3 is a cross-sectional view of an embodiment of a device that includes a fluid dispenser, which includes a catheter.[0023]
FIGS.[0024]4A-4E are cross-sectional views of the device of FIG. 3 in a body lumen, which illustrate steps in some embodiments of methods for removing an object from the body lumen.
FIG. 5 is a cross-sectional view of an embodiment of a device that is positioned within a ureter for removal of a kidney stone.[0025]
DESCRIPTIONNow referring to FIG. 1, general principles of an exemplary embodiment of the invention are described. FIG. 1 is a cross-sectional view of a body lumen containing a blockage. The lumen is defined by a[0026]duct15, for example, a ureter. Anobject10, for example, a kidney stone, partially blocks theduct15. According to a general principle of the invention, a fluid11 introduced into theduct15 serves to dislodge theobject10 from the lumen wall of theduct15 and/or propel theobject10 through the lumen.
If the[0027]object10 is embedded in the wall of theduct15, it can be dislodged by the flow of the fluid. The fluid can also distend the duct, to help dislodge theobject10, and/or to help move theobject10 through the lumen by increasing the width of the lumen.
Now referring to FIG. 2, an embodiment of a device for removing an object from a body lumen is described. FIG. 2 is a cross-sectional view of the[0028]device20 positioned in a body lumen. Anobject10 is embedded in the wall of the body lumen. Thedevice20 includes acatheter22, afluid lumen23 defined by thecatheter22, anaperture23A that is in fluid communication with thefluid lumen23, and amember21 located at a distal end of thecatheter22.
To remove the[0029]object10 from the body lumen, a portion of thecatheter22 is placed within the body lumen, with themember21 to one side of theobject10. Themember21 then serves to hold the device in position by pressing against the walls of the body lumen. Themember21 may be expansible, and can include, for example, a balloon or a gel. A fluid11, for example, a saline solution, is directed through thefluid lumen23. The fluid11 exits thelumen23 via theaperture23A. Movement of the fluid11 within the body lumen can dislodge theobject10, and can propel theobject10 through the body lumen. Themember21 can block the flow offluid11 in a direction that is away from theobject10.
The[0030]device20 can be configured to deliver fluid of a sufficient quantity or pressure to dislodge or propel the object. Further, the quantity of fluid and the pressure of the fluid can be restricted to levels that are unlikely to cause any undesirable side effects for a patient.
Now referring to FIG. 3, a preferred embodiment of a device for removing an object from a body lumen is described. FIG. 3 is a cross-sectional view of a[0031]device30. Thedevice30 includes a fluid dispenser, which includes afirst catheter32, and asecond catheter36. A portion of thefirst catheter32 is disposed within thesecond catheter36, and can slide with respect to thesecond catheter36.
The first catheter includes a[0032]fluid lumen33, through whichfluid11 can be delivered to a body lumen. Adistal expansible member31, is in mechanical communication with thefirst catheter32, and a proximalexpansible member38 is in mechanical communication with thesecond catheter36.
In a preferred embodiment, the[0033]expansible members31,38 are balloons. Thecatheters32,36 includelumens34,37 for delivery of inflation fluid to the balloons. A fluid, such as a saline solution, can be added or removed from aballoon31,38 to control the size of theballoon31,38, and to control the pressure of theballoon31,38 against the wall of the body lumen.
Now referring to FIGS.[0034]4A-4E, some illustrative embodiments are described of methods for removing an object from a body lumen, which utilize thedevice30 of FIG. 3. FIGS.4A-4E are cross-sectional views of thedevice30 in a body lumen, which illustrate steps in some embodiments of methods for removing an object for the body lumen.
A portion of the[0035]device30 is inserted into the body lumen, while theballoons31,38 are in a collapsed state (see FIG. 4A). The spacing between theballoons31,38 can be adjusted by sliding thecatheters32,36 relative to each other (see double arrow in FIG. 4A.) The distal balloon can then be expanded to secure the position of thefirst catheter32 within the body lumen (see FIG. 4B).
The[0036]proximal balloon38 can be expanded before, simultaneously with, or after the expansion of thedistal balloon31. In one embodiment, the proximal balloon is inflated to a lower pressure, P2, than the pressure, P1, of the distal balloon.Fluid11 is then dispensed into the >portion of the body lumen defined by theballoons31,38. When the pressure of the fluid11 exceeds that of the pressure of theproximal balloon38, the fluid11 begins to flow past theproximal balloon38. The flow of the fluid11 against theobject10 can dislodge the object and can propel the object through the lumen, past the proximal balloon38 (see FIG. 4C.)
In some embodiments, the pressure of the[0037]proximal balloon38 is decreased to enhance the flow offluid11, after depositing a predetermined quantity offluid11 into the portion of the body lumen, or depositingfluid11 to a predetermined pressure.
In some embodiments, a predetermined quantity fluid is dispensed while the balloons are fully inflated (see FIG. 4D.) The predetermined quantity of fluid causes the portion of the body lumen to become distended. This stretching of the body lumen can help dislodge the[0038]object10 from the wall of the body lumen. Theproximal balloon38 can then be reduced in size, for example, fully collapsed, to permit the dispensedfluid11 to flow past the proximal balloon38 (see FIG. 4E.) Thedistal balloon31 remains expanded, in part, to block fluid11 from flowing in a distal direction past the location of thedistal balloon31.
Dispensing a predetermined quantity of fluid, and releasing the predetermined quantity of fluid, can be repeated until the object is dislodged and/or flushed past the[0039]proximal balloon38. In some embodiments, the fluid11 is dispensed at a sufficient pressure while the fluid11 flows against theobject10 to dislodge theobject10 and/or to cause the object to move through the body lumen.
A device can further include aids to help the positioning of the device in the body lumen. For example, a balloon can include radio-opaque markers that provide visibility under fluoroscopic imaging devices.[0040]
A device can include balloons that are, for example, selected from those known in the catheter arts. A balloon can include various materials, for example, urethane, silicone or other elastomer. The balloons can have separate inflation supplies, to permit different balloon pressures. The fluid delivered to the body lumen can be a saline solution or other biocompatible materials, for example, other isotonic fluids, for example, a fluorocarbon.[0041]
Now referring to FIG. 5, embodiments of a device and method of removal of a kidney stone from a ureter are described. FIG. 5 is a cross-sectional view of a device that is positioned within a[0042]ureter55, which leads to akidney56, for removal of a kidney stone50.
The device is similar in construction to the device of FIG. 3. The device includes a[0043]catheter37, which has been inserted through the urethra andbladder57 into theureter55. Theureter55 is obstructed by the kidney stone50. Aproximal balloon38A, attached to a second catheter36A, and a distal balloon31A, attached to afirst catheter32A, have been positioned on either side of the stone50.
The[0044]catheter37 extends to apump53, which directs saline fluid11A under pressure to the portion of theureter55 that contains the stone50. Thepump53 is powered by amotor54, and is held within a handle52. The device also includes afluid source51, which supplies saline fluid11A to thepump53. In some embodiments, thepump53, themotor54, the handle52 and/or thefluid source51 remain outside the body.
In preferred embodiments, the[0045]pump53 includes features that prevent application of a damaging pressure to body tissue. In one embodiment, the pump is a non-positive displacement pump having a preset pressure limit. In another embodiment, the pump is a positive displacement pump having a pressure release, limiting valve.
A preferred embodiment of a method of using the device of FIG. 5 includes advancing the[0046]catheter32A through the urinary tract, under fluoroscopic guidance, to the site of an ingrown stone. The distal balloon31A is inflated with saline solution once the balloon31A is at the desired location. Theproximal balloon38A is then advanced with the second catheter36A, by sliding the second catheter36A relative to thefirst catheter32A, until the distance between the proximal anddistal balloons31A,38A is at a preferred separation. For example, upon release of a quantity of saline fluid11A, it is possible to obtain greater fluid velocity and turbulence through use of reduced separation between theballoons31A,38A.
A guidewire can be utilized to assist insertion of the device. A variety of suitable guidewires are known to those having experience in the catheter arts.[0047]
The[0048]proximal balloon38A is then inflated with saline solution until it exerts a pressure, on the ureter wall, that is less than the pressure exerted by the distal balloon31A. A tight seal at the distal balloon31A, and a loose seal at theproximal balloon38A are obtained. Warm, high-pressure saline is then flushed through the ureter, and the excess flows past theproximal balloon38A, and into thebladder57.
The fluid[0049]11A dislodges the stone, and flushes it into thebladder57. Theballoons31A,38A are then deflated, and the device is removed from the body. The stone50 can be removed from thebladder57 by, for example, conventional means.
A variable spacing between balloons has further advantages. For example, the spacing can be varied to include more than one stone in a body lumen portion, when needed. The spacing can be varied to provide variable saline flush pressures.[0050]
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. For example: an embodiment of a device can include fixed balloons to provide a more stable configuration and simpler manufacturing; a catheter can include a printed electroactive polymer to provide self-propulsion; balloons can be coated, for example, with hydrogels, drugs or polymers; and a drug can be delivered to the vicinity of an object via the fluid lumen. Accordingly, the invention is to be defined not by the preceding illustrative description but instead by the spirit and scope of the following claims.[0051]