Patent Publication Number: US-2009234281-A1

Title: Fluid feeder and balloon catheter

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fluid feeder and a balloon catheter which are employed by feeding fluid into a balloon. 
     2. Description of Related Art 
     In general, various types of balloon catheters provided with a balloon in the vicinity of a distal end of the catheters are employed in a medical field, for example, urological catheters provided with a balloon for medical use such as indwelled urinary catheters, endotracheal tubes, digestive tract catheters and cardiac balloon catheters for cardiac pumping. 
     When the balloon of the balloon catheters is inflated, in general, a fluid feeder (such as a syringe of medical use) is fitted onto a port located at a handheld side which is connected to the balloon so as to flow a fluid. The balloon is inflated to a required volume by injecting the fluid. 
     When a gallstone is removed with the balloon catheters described above, a balloon  100  is inflated with a slightly larger diameter than that of a bile duct  110 . Thereafter, a gallstone  111  is carried closer to the entry of the bile duct by scraping the gallstone  111  with the balloon  100 . 
     Due to the narrow diameter of the entry of the bile duct, the balloon catheters carrying the gallstone can not be withdrawn from the bile duct without reducing the diameter of the balloon  100 . Therefore, in normal practice, an assistant operates the fluid feeder in conjunction with the balloon  100  being pulled by a user; hence the pulling operation is performed by deflating the balloon  100 . 
     However, it is not easy to synchronize the operations of the user and the assistant. If the synchronized operation is not carried out correctly; in this case, if the deflation of the balloon  100  is too fast, the gallstones  111  is separated from the balloon  100  and left in the bile duct. 
     On the other hand, if the deflation of the balloon  100  is too slow, the balloon  100  may compress the exit of the bile duct  110 , or the balloon  100  may rupture. 
     Further, as the diameter of the balloon becomes smaller and smaller, the diameter will change significantly with a slight operation of the fluid feeder. This is problematic as adjustment of the diameter of the balloon to a desirable size becomes difficult as a result. 
     SUMMARY OF THE INVENTION 
     The present invention was conceived in view of the above-described circumstances, and has as its objective the provision of a fluid feeder which can adjust/control the diameter of a balloon to a desirable diameter regardless of the diameter of the balloon. 
     Another object of the present invention is the provision of a balloon catheter which can reliably adjust the diameter of the balloon to a desirable diameter. 
     According to a first aspect of the present invention, a fluid feeder which feeds a fluid into a balloon made of an elastic material so as to inflate, the fluid feeder provided with: a cylinder that is formed in a cylindrical shape provided with a first port and a second port on each end thereof, and contains the fluid; a plunger that is inserted into the cylinder via the second port in a freely advancing and retracting manner in an axial direction, in order to push out the fluid contained in the cylinder from the first port to the outside of the cylinder; an adjustor that is attached to the plunger and regulates a moving distance of the plunger so as to inflate the balloon to a predetermined diameter; and a fixing portion that is provided on the cylinder, and fixes the plunger onto the cylinder to a position which corresponds to the moving distance regulated by the adjustor; wherein: 
     the adjustor has a plurality of engaging members which regulates the moving distance corresponding to a plurality of the different inflated diameters, and the fixing portion has an engaged portion which engages with the engaging members to fix the plunger. 
     According to a second aspect of the present invention, a balloon catheter provided with a balloon made of an elastic material, and includes the fluid feeder of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the balloon catheter provided with the fluid feeder according to a first embodiment of the present invention. 
         FIG. 2  is a perspective view of the fluid feeder of the present invention. 
         FIG. 3  is a plain view of the fluid feeder of the present invention. 
         FIG. 4  is a cross-sectional view as seen from a line A-A of  FIG. 3 . 
         FIG. 5  shows an action of the plunger and the moving distance. 
         FIG. 6  is an example of a graph showing a relationship between the size of the diameter of the balloon and the moving distance of the plunger. 
         FIG. 7  shows the balloon catheter fixing onto an endoscope. 
         FIG. 8  shows the action of the balloon catheter  2  during use. 
         FIG. 9  shows the balloon in an inflated state. 
         FIG. 10  shows a state in which the adjustor and the engaged portion are engaged. 
         FIG. 11  shows an action of the engagement between the adjustor and the engaged portion to change to an ‘OFF’ state. 
         FIG. 12  shows an action of the engagement between the adjustor and the engaged portion to change to ‘OFF’ state. 
         FIG. 13  is an enlarged view of the adjustor and the engaged portion of a fluid feeder according to a second embodiment of the present invention. 
         FIG. 14  is an enlarged view of the adjustor and the engaged portion of a fluid feeder according to a modified examples of the present invention. 
         FIG. 15  is an enlarged view of the adjustor and the engaged portion of a fluid feeder according to a modified examples of the present invention. 
         FIG. 16A  shows a state in which a gallstone is removed by a conventional balloon catheter. 
         FIG. 16B  shows a state in which a gallstone is left in the vicinity an entry of a bile duct. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A fluid feeder according to a first embodiment of the present invention will be explained with reference to  FIGS. 1 through 12 . 
       FIG. 1  is a view showing a balloon catheter  2  provided with a fluid feeder  1  according to the present embodiment. The balloon catheter  2  includes a long flexible sheath  3 , a balloon  4  provided in the vicinity of a distal end of the sheath  3 , and the fluid feeder  1  provided at a proximal end of the sheath  3 . 
     The sheath  3  is made of a flexible material, such as resin, and is provided with three lumens; a first lumen  5  for feeding fluid to a balloon  4 , a second lumen  6  for inserting a guidewire which guides a distal end of the balloon catheter  2  to a desirable position of a body cavity of a patient, and a third lumen  7  for transporting various fluid, such as a contrast agent, into the body cavity of the patient. 
     A distal end of the first lumen  5  passes through an outer periphery surface of the sheath  3 , and opens into the balloon  4 . Distal ends of the second lumen  6  and the third lumen  7  open to the distal end of the sheath  3 . However, the distal ends of the second lumen  6  and the third lumen  7  may also open at any position other than the distal end of the sheath  3 . 
     The lumens  5 ,  6 ,  7  do not integrate each other, rather, they are provided within the sheath  3  independently. The three independent lumens extend and separate from the proximal ends, forming three ports: a first port  8 , a second port  9  and a third port  10 . The fluid feeder  1  is connected to the first port  8 . 
     A proximal end of the sheath  3  also includes an anchor  11  which fixes the balloon catheter  2  at, for example, an endoscopic device or the like. 
     The balloon  4  is made of an elastic material so as to inflate by gradually expanding the diameter thereof when a fluid such as liquid or gas which is fed from the fluid feeder  1  accumulates inside thereof. As for the material made of the balloon  4 , for example, natural rubber, synthetic rubber, polyurethane, polyamide elastomer, silicone, and the like can be employed suitably according to its purpose. 
       FIG. 2  is a perspective view of the fluid feeder  1 ,  FIG. 3  is a plain view of the fluid feeder  1 , and  FIG. 4  is a cross-sectional view as seen from a line A-A of  FIG. 3 . As indicated in  FIGS. 2 through 4 , the fluid feeder  1  includes; a cylindrical-shaped cylinder  12 , a plunger  13  which is inserted into the cylinder  12 , an adjustor  14  provided on the plunger  13 , and a fixing portion  15  provided on the cylinder  12 . 
     The cylinder  12  is formed in a cylindrical shape, containing fluid inside a lumen thereof. The fluid contained may be a gas such as air, or a liquid, such as a saline solution. Both ends of the cylinder  12 , a first end  12 A at the distal end, and a second end  12 B at the proximal end, are opened. The first end  12 A engages with the first port  8  so that the shape of the first end  12 A is constructed in a manner so as to allow engagement with the first port  8 . 
     The plunger  13  includes a main body  16  which is inserted into the cylinder, and a grip  17  provided at a proximal side of the main body. A distal side of the main body  16  is inserted into the lumen of the cylinder  12 , so as to advance and retract the main body  16  inside of the cylinder  12  along a longitudinal direction thereof. A shape of the distal end of the main body  16  is substantially the same as the inner diameter of the cylinder  12 . As shown in  FIG. 5 , when the main body  16  is advanced toward the first end  12 A of the cylinder  12 , the fluid contained in the cylinder  12  is pushed out from the first end  12 A. 
     A grip  17  is a member gripped by a user when the plunger  13  is operated, and there are no limits in the shape and material. The grip  17  in the proceeding embodiment is formed in a cylindrical-shape, provided with a slip resistance  17 A for ease of gripping. 
     The adjustor  14  is a plate member extending from the grip  17  in a direction substantially parallel to the main body  16  of the plunger  13 . A convex portion  14 A is formed at a distal end of the adjustor  14  so as to prevent the plunger  13  from escaping from the cylinder  12 . 
     A plurality of engaging projections  18  which regulate an moving distance of the plunger  13  are formed on a surface of the adjustor  14  opposite to a surface facing to the main body  16 . A distance between each of the engaging projections  18  is set longer as the position of the projections  18  is closer to the proximal end of the plunger  13 . For example, as shown in  FIG. 5 , a distance L 2  between an engaging projection  18 B and an engaging projection  18 C located more closer to the proximal side of the plunger  13  with respect to the projection  18 B is longer than that of L 1  between an engaging projection  18 A and the engaging projection  18 B located closer to the proximal side of the plunger  13  with respect to the projection  18 A. 
     The distance between each of the engaging projections  18  is determined depending on the characteristics of the balloon  4  which are a target member for the fluid feeder  1  feeding a fluid thereinto.  FIG. 6  shows an example of a graph indicating the relationship between the size of a diameter of the balloon and the moving distance of the plunger  13 . 
     Note that ‘a moving distance’ refers to a distance D indicated by the same part of the plunger  13  in the fluid feeder  1  connected to the balloon catheter  2  in a state in which the balloon  4  is completely deflated. As shown in  FIG. 5 , the distance D is a distance between a reference position P 1  which is a starting position of the plunger  13  and a position P 2  after the movement of the plunger  13  completes. 
     It is preferable if the reference position P 1  of the plunger  13  is set such that the distal end of the plunger  13  is positioned in the vicinity of the second end  12 B of the cylinder  12 . In this way, a wider range of the moving distance can be achieved. However, the present invention is not limited thereto; any positions may be set as the reference position P 1 . According to the present embodiment, the convex portion  14 A of the adjustor  14  determines the position of the plunger  13  abutting a fall-off prevention portion of the fixing portion  15  as a reference position. 
     As shown in  FIG. 6 , the difference of the moving distance which is required by the plunger  13  for further inflating a pre-inflated balloon with a desirable diameter by a predetermined amount, for example by 1 mm, increases as the diameter of the pre-inflated balloon increases. Taking into consideration the relationship described above, if a distance (space) between the adjacent projections  18  is set so as to gradually increase as increasing a diameter of the balloon, it is possible to achieve an inflation of the diameter of the balloon which corresponds to each of the projections  18  with an equal interval, for example by 1 mm. Note that a position where the engaging projections  18  is formed may be altered depending on, for example, inflation and deflation characteristics of the balloon, an interval size for achieving a desirable diameter and a desirable size of diameter to be held after inflation, or the like. 
     The fixing portion  15  is disposed on an outer periphery of the cylinder  12 , provided with an engaged portion  19  which engages with the engaging projections  18  of the adjustor  14 , a switch  20  which changes the status of engagement between the engaged portion  19  and the adjustor  14  so as to engage and disengage, and a finger resting portion for a user to rest his/her fingers at the time of the operation. 
     The engaged portion  19  is positioned further outward in a radial direction of the cylinder  12  with respect to the engaging projections  18 , and a projection  19 A is protruded so as to oppose to the engaging projections  18 . When the plunger  13  slides through the inside of the cylinder  12  and a proximal side face of the engaging projections  18  and a distal side face of the projection  19 A comes into contact, a positional relationship between the plunger  13  and the cylinder  12  is maintained. At this time, the inflation of the balloon  4  is maintained with the inflated diameter corresponded to the moving distance of the plunger  13  which is regulated by the engaging projections  18 . 
     As shown in  FIGS. 2 and 3 , a frame-shaped fall-off prevention portion  19 B is disposed on the engaged portion  19 , and the adjustor  14  is passed through the fall-off prevention portion  19 B. When the plunger  13  is retracted toward the proximal end, the convex portion  14 A of the adjustor  14  abuts onto the fall-off prevention portion  19 B at a position where the distal end of the plunger  13  comes close to the second end  12 B of the cylinder  12 . As a result, the plunger  13  is no longer retracted further toward the proximal end so as to prevent the plunger  13  from escaping from the cylinder  12 . 
     One end of the switch  20  is attached to the engaged portion  19  in a freely rotating manner about the end. When the switch  20  is rotated so as to interpose between the engaged portion  19  and the adjustor  14 , the engaged portion  19  and the adjustor  14  are separated so as not to engage each other. This action will be described later. 
     The action of the balloon catheter  2  as designed above during use will not be explained. 
     First, an endoscope is inserted into a body cavity of a patient, and the distal end thereof is moved into the vicinity of a treatment target tissue. 
     At this time, the balloon catheter  2  should be ready for use. A user retracts the plunger  13  of the fluid feeder  1  toward the proximal side so as to position the plunger  13  at the reference point P 1  described above, resulting a fluid flowing into the cylinder  12  to accumulate therein. Then the first end  12 A of the cylinder  12  is connected to the first port  8 . 
     The user inserts the distal end of the balloon catheter  2  into an instrument channel of the endoscope (not shown) from a forceps port  121  of the endoscope  120  so as to protrude the distal end of the balloon catheter  2  from a distal end of the endoscope  120 . Normally, an assistant operates the fluid feeder  1  by standing close to the user; however, the user may directly operate the fluid feeder  1  by himself/herself, by fixing a handheld side of the balloon catheter  2  to the endoscope  120  with the anchor  11 , as shown in  FIG. 7 . 
     When the balloon  4  is inflated, the user grips the grip  17  of the plunger  13  resting his/her fingers on the finger resting portion  21 . The plunger  13  is advanced into the syringe  12  by pulling the syringe  12  relative to the plunger  13 . The projection  19 A of the engaged portion  19  advances toward the engaging projections  18  positioned further to the proximal side, by subsequently clicking into the space between the adjacent engaging projections  18  of the adjustor  14 . Simultaneously, a fluid contained in the cylinder  12  is pushed out by the plunger  13 , feeding into the balloon  4  via the first port  8  and the first lumen  5  so as to inflate the balloon  4  as shown in  FIG. 9 . 
     When the user stops the advancing operation of the plunger  13 , the balloon  4  is deflated so that a pressure which pushes the fluid back to the syringe  12  exerts onto the plunger  13 . As a result, the engaging projections  18  of the adjustor  14  move toward the proximal end. Then, a proximal side slant face of the engaging projections  18  positioning closer to the distal end with respect to the projection  19 A and closest to the projection  19 A, comes into a contact with a distal side slant face of the projection  19 A causing the plunger  13  to stop. Accordingly, the moving distance of the plunger  13  is maintained constant, so that the diameter of the balloon  4  is regulated and maintained as a set diameter size corresponding to the moving distance. 
     When the diameter of the balloon  4  is changed, the plunger  13  is advanced and retracted with respect to the cylinder  12  by the aforementioned action, so as to engage the projection  19 A of the fixing portion  15  and the engaging projections  18  of a desirable position. Hence, the moving distance of the plunger  13  is regulated by the set position of the corresponding engaging projections, and the diameter of the balloon  4  changes according to the moving distance. When the plunger  13  advances and retracts and the engaged portion  19  rides over the engaging projections  18 , the operator will feel a click. Hence, a user can easily recognise the number of levels shifted (in other words, a number of the engaging projections  18  in which the projection  19 A has ridden over) without actually seeing a manipulation of the device. Accordingly, a diameter of the balloon  4  can be easily regulated. Further, if the plunger  13  is quickly retracted and the projection  19 A of the fixing portion  15  is engaged to the engaging projections  18  at the position where the retraction of the plunger  13  is completed, in order to create a negative pressure state inside of the cylinder  12 . As a result, the balloon  4  can be deflated faster. 
     When the balloon  4  is completely deflated, the switch  20  is pushed in so as to insert between the projection  19 A and the engaging projections  18 , as shown in  FIGS. 11 and 12 . Then as shown in  FIG. 12 , the projection  19 A is pushed up so as to separate the projection  19 A from the engaging projections  18  by the switch  20 . Accordingly, the projection  19 A and the engaging projections  18  are no longer engaged, changing the status of the fixing portion  15  to ‘OFF’. As shown in  FIG. 11 , the ‘OFF’ state can be maintained by engaging an end portion  20 A of the switch  20  onto the convex portion  15 A provided on the fixing portion  15 . At this ‘OFF’ state, the plunger  13  can be smoothly slide within the cylinder  12 . 
     When the fixing portion  15  enters the ‘OFF’ state, the plunger  13  is pushed back by a deflation of the balloon  4  so that the balloon  4  completely deflates without the user operating the plunger  13 . Alternatively, the ‘OFF’ state may be employed when the plunger  13  is pulled toward the proximal end at the aforementioned preparation stage of the balloon catheter  2  prior to use. 
     According to the fluid feeder  1  of the present embodiment, the moving distance of the plunger  13  is regulated by the engaging projections  18  provided on the adjustor  14  so as to inflate the diameter of the balloon  4  to a size which corresponded to the moving distance. Then, by engaging the engaging projections  18  and the projection  19 A of the fixing portion  15 , the inflated diameter of the balloon  4  is maintained. By virtue of the engaging action, the diameter of the balloon can be accurately regulated, even within a relatively small range of a diameter such that a diameter changes significantly with slight movement of the plunger. 
     Furthermore, since a distance between adjacent engaging projections is set to be increased as the moving distance of the adjustor  14  increases, it is possible to set the change of diameter (the difference by which the diameter changes) of the balloon  4  to be the same. The change of diameter is caused by clicking the engaging projections  18  which engages the projection  19 A of the engaged portion  19  into the space between the next adjacent space toward the distal or proximal ends. Accordingly, the inflating diameter of the balloon  4  can be easily regulated at an equal interval, for example by 1 mm. 
     Furthermore, since the inflated state with a desirable diameter of the balloon  4  is maintained by the fixing portion  15 , it is not necessary to provide a mechanism such as a faucet and the like, between the fluid feeder and the first port  8  for preventing a back flow of a fluid into the cylinder  12 . Therefore, the structure of the balloon catheter  2  can be simplified, achieving lowering a manufacturing cost by employing the fluid feeder  1 . 
     The present embodiment described examples in which the balloon catheter  2  was inserted into the endoscope  120 . However, the present invention is not limited thereto; the balloon catheter  2  may be used without being fixed/inserted into the endoscope if a treatment is performed without the endoscope. 
     Next, a second embodiment of the present invention will be explained with reference to  FIG. 13 . A fluid feeder  31  according to this embodiment differs from the proceeding fluid feeder  1  with regard to the structure of the adjustor  14 . 
     In the following description, components that are the same as the first embodiment shall be provided with the same numeric symbol and redundant description shall be omitted. 
       FIG. 13  is an enlarged view of an adjustor  32  and the engaged portion  19  of a fluid feeder  31 . The size of each engaging projection  33  formed on the adjustor  32  differs and an engaging projection  33 A provided on a proximal side of the adjustor  32  is larger than an engaging projection  33 B provided on the distal side thereof. Accordingly, the size of the engaging projections  33  depends on its position on adjustor  32 . The size increases as the position of the engaging projections  33  is closer to the proximal end of adjustor  32 . 
     As the plunger  13  advances, the projection  19 A of the engaged portion  19  engages with the engaging projections  33  positioned closer to the proximal side. As a result, more fluid is supplied into the balloon  4  so as to increase the diameter of the balloon  4 . At this time, tension exerted on the balloon  4  increases so as to increase a force exerted toward the retracting direction of the plunger  13  in conjunction with the increase of the diameter of the balloon. 
     According to the fluid feeder  31  of the present embodiment, since the size of the engaging projections positioned closer to the proximal side of the adjustor  32  is designed to increase, an engagement force exerted between the projection  19 A and the engaging projections  33  (a force required for the projection  19 A rides over the engaging projections  33  abutted thereon) increases as a moving distance of the plunger  13  increases. 
     Therefore, although a stronger force exerts to the direction in which the plunger  13  is retracted with respect to the cylinder  12  by increasing a diameter of the balloon  4 , the positional relationship between the plunger  13  and the cylinder  12  is maintained so as to maintain the diameter of balloon. 
     While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. 
     For example, as shown in  FIGS. 10 and 13 , in the proceeding embodiment, the angle of slant faces of both distal and proximal sides of the engaging projections of the adjustor were the same. However, the shape of the engaging projections is not limited thereto. Modified examples are described herein below. 
       FIG. 14  is an enlarged view of an adjustor  34  as a modified example of the present invention. An angle formed by a first slant face  35 A (at a distal side) between a base of the adjustor  34  parallel to an axis of the plunger  13  (in other words, it is an angle formed by the first slant face  35 A between the axis of the plunger  13 ) is set smaller than that of a second slant face  3513  (at the proximal side). As a result of this design, lesser force is required for the projection  19 A to ride over the engaging projections  35  when the plunger  13  is advanced. Therefore, the inflation operation of the balloon  4  can be easily performed as well as having an advantage of reliably controlling the diameter of the balloon. 
     Alternatively, in the proceeding embodiment, the projection of the engaged portion and the engaging projections of an adjustor were engaged. However, in place thereof, it is also acceptable to design a concave portion  37  on an adjustor  36  which engages with the projection  19 A of the engaged portion  19  as shown in a modified example of  FIG. 15 . In this case, in order to increase the engagement force at the concave portion  37  as the moving distance of the plunger  13  increases, a depth of the concave portion  37  may be increased as the position is closer to the proximal end of the adjustor  36 . 
     Further, a fixing portion may be constructed by providing the concave portion at the engaged portion so as to engage with the engaging projections of the adjustor; or different angles may be formed at the first slant face and the second slant face between the axis of the plunger, as shown in the aforementioned modified example. 
     For example, the proceeding embodiments described examples in which a fluid feeder was used in the balloon catheter. However, the invention is not limited thereto; for example, the fluid feeder of the present invention may also be used in, for example, an inner diameter measuring device which measures an inner diameter of the tube by inflating a balloon in the tube so as to fit into. The inner diameter can be measured easily since the diameter of the balloon can be regulated at a desirable size. 
     Finally, the invention is not to be considered as being limited by the foregoing description and is only limited by the scope of the appended claims.