Patent Publication Number: US-2006020269-A1

Title: Device to aid in stone removal and laser lithotripsy

Description:
FIELD OF THE INVENTION  
      This device relates generally to medical devices and procedures and more particularly to medical devices and procedures for assisting in the removal of stones from a body.  
     BACKGROUND OF THE INVENTION  
      Extraction devices have been used for the removal of stones or calculi from the urinary tract of the human body. Typically, the distal portion of existing devices includes wires or strips that can be manipulated inside the body to expand, forming an open basket. Through further manipulation, the targeted stone can be captured within the basket. The device is then withdrawn from the body, thereby removing the stone.  
      The baskets of existing devices are rigid as compared to the surrounding body tissue. Due to their rigidity, these devices can cause harm to the body tissue or body structure in which stones reside. For example, existing devices may not be flexible enough to conform to the contours of the treatment location during capture or removal of the stone. As a result, manipulation of the device in the body and removal of a stone residing in, for example, the ureter may damage the ureter wall. Such damage to the ureter wall may cause various trauma to the wall, necessitating the placement of a temporary stent within the ureter.  
      Existing devices may also use lasers or pneumatics to diminish the size of the stone before removing it. While being acted on by these devices, however, parts of the stone may break free and migrate to other parts of the body. They may also migrate to calyxes of the same body structure in which the stone resides.  
      The present disclosure provides a device that assists in stone removal that avoids some or all of the aforementioned shortcomings of existing devices.  
     SUMMARY OF THE INVENTION  
      In accordance with one aspect of the present disclosure, a medical device includes a delivery tube and a sponge configured for deployment from the delivery tube and into the urinary tract for assisting in the removal of a stone.  
      In accordance with another aspect of the present disclosure, a method for assisting the removal of a stone from a body includes deploying a sponge into the body and contacting the stone with the sponge to facilitate removal of the stone from the body.  
      In accordance with yet another aspect of the present disclosure, a method for assisting the removal of a stone from a body includes deploying a sponge into the body and prohibiting the stone from migrating distal the sponge while the stone is subject to a procedure.  
      It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a cross-sectional view of a stone removal assistance device according to an exemplary embodiment of the present disclosure;  
       FIG. 2  is a cross-sectional view of the device of  FIG. 1  positioned within the body;  
       FIG. 3  is an operational view of the device of  FIG. 1 ;  
       FIG. 4  is another operational view of the device of  FIG. 1 ;  
       FIG. 5  is a cross-sectional view of a sponge according to an exemplary embodiment of the present disclosure;  
       FIG. 6  is a cross-sectional view of a sponge according to another exemplary embodiment of the present disclosure;  
       FIG. 7  is a cross-sectional view of a sponge according to still another exemplary embodiment of the present disclosure;  
       FIG. 8  is a cross-sectional view of a sponge according to yet another exemplary embodiment of the present disclosure; and  
       FIG. 9  is a further operational view of the device of  FIG. 1 . 
    
    
     DETAILED DESCRIPTION  
      Exemplary embodiments of the present disclosure are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
       FIG. 1  illustrates a device  5  that assists in stone removal according to an embodiment of the present disclosure. The device  5  may include a delivery tube  10 , an urging member  15 , and a sponge  20  having at least one tethering member  25  extending through the sponge  20  and forming a first and second leg  27 ,  29 .  
      As shown in  FIG. 1 , the delivery tube  10  may provide a channel  30  within which the urging member  15  and the sponge  20  may move. The delivery tube  10  may be constructed of tubing commonly known in the art. Such tubing materials may include, but are not limited to, stainless steel or nitinol. They may also include plastics, composites, or polymers, such as urethanes, Teflon, polyimide, or nylons, depending on the desired rigidity or flexibility of the delivery tube  10 . Braiding or webbing made from these same materials could also be added to the delivery tube  10  to achieve a desired rigidity.  
      The delivery tube  10  or delivery member may be a tubular member, and may be cylindrical or some other like shape to facilitate easy insertion into the body, and easy manipulation once inside of the body. The delivery tube  10  may be hollow and may be relatively flexible as compared to the urging member  15 . The channel  30  of the delivery tube  10  may also provide one or more additional passages within which other medical devices such as, but not limited to, laser fibers  35  ( FIG. 9 ) used in intracorporeal laser lithotripsy may travel.  
      The sponge  20  may be any material that expands when coming into contact with a fluid. For example, the sponge  20  may be a polyvinyl alcohol sponge, or other sponge-like material commonly known in the art. As shown in  FIG. 2 , in its unexpanded state, the sponge  20  may be compressed to fit within the channel  30  of the delivery tube  10 . To minimize the size of the device  5 , it may be desirable for the delivery tube  10  to be as small as possible thereby limiting the size of the sponge  20  in its unexpanded state. The sponge  20  may be compressed to fit within the channel  30  by any means possible. For example, the sponge  20  may be compressed through radial compression in which it is twisted clockwise or counter-clockwise relative to the delivery tube  10  while being inserted therein. The sponge  20  may also be folded or pleated for insertion into the delivery tube  10 . As a further example, the sponge  20  may be compressed for insertion by pressing a rod or other implement on two or more of its sides.  
      On the other hand, the sponge  20  may be of any size in its expanded state and, as shown in  FIG. 4 , may be sized to extend fully across the ureter or other body structure of the patient. The sponge  20  may be slightly oversized relative to the body structure to impede the passage of material between the sponge  20  and the body tissue  45  ( FIG. 4 ). In its expanded state, the sponge  20  may have a diameter of approximately 2 mm to 10 mm, and may have a compression ratio (expanded state to unexpanded state) of approximately 10 to 1. It is understood that these diameters and ratios are merely exemplary and that the device  5  of the present disclosure may utilize sponges  20  that fall outside of these ranges.  
      The sponge  20  may be of any shape or design to facilitate the immobilization and removal of stones within the urinary tract. For example, the sponge  20  may form a cylindrical or drum-like shape in an expanded state as shown in  FIG. 4 . These shapes or designs may correspond to the body structure in which a stone  40  resides. They may also be designed to facilitate the compression of the sponge  20  and assist in stone retrieval and immobilization. For example, although not shown, a side of the sponge  20  may be concave. This shape may enable the user to compress the sponge  20  with less force or effort and may improve the immobilization and retrieval characteristics of the sponge  20  while in its expanded state.  
      In addition, the sponge  20  may also be shaped to facilitate re-entry of the sponge  20  into the delivery tube  10 . For example, a side of the sponge  20  may be angled or tapered to ease entry of the sponge  20  into the channel  30  of the delivery tube  10  after the sponge  20  has absorbed fluid and is in its expanded state. To accomplish re-entry, the sponge  20  may release at least some of the fluid absorbed.  
      Referring to  FIG. 2 , the stone  40  may be a kidney stone, a struvite, a uric acid stone, a cystine stone, or other solid deposit commonly removed from a body structure or passageway within the body. Such stones  40  may contain various combinations of chemicals including, but not limited to, calcium, oxalate, and phosphate. The stone  40  may be of any size, and could have a length or diameter of approximately 1 mm to 12 mm. It is understood that these lengths and diameters are merely exemplary and that aspects of the present disclosure may assist in the removal of stones  40  larger or smaller than those discussed herein.  
      It is further understood that stones  40  may be of any shape, and could be, for example, flat, round, smooth, or jagged. Although  FIGS. 2-4  and  FIG. 9  show a stone  40  in close proximity to body tissue  45 , the device  5  may assist in the immobilization and removal of stones  40  that are both impacted and free floating.  
      As illustrated in  FIGS. 2-4 , the sponge  20  may be urged from the distal end  50  of the delivery tube  10  by the urging member  15 . As used herein, the term “distal” means furthest from the user. The urging member  15  may be a solid rod or tube, and may be constructed from any material commonly known in the art including, but not limited to, stainless steel or nitinol mandrel tubing, or polymers, such as urethanes or nylons. The urging member  15  may be of a size and shape to fit within the delivery tube  10 . The urging member  15  may also be of a size, shape, and rigidity to urge the sponge  20  to exit from the distal end  50  of the delivery tube  10  once the device  5  has been delivered to a desired location within the urinary tract.  
      As noted above, the sponge  20  may be secured to the delivery tube  10  by a coupling member in the form of a tethering member  25 . The tethering member  25  may include, but is not limited to, a suture, wire, or nylon cord. The tethering member  25  may enable the user to manipulate or retrieve the sponge  20  once delivered inside of a body structure.  
      As illustrated in  FIG. 5 , the tethering member  25  may pass through the body of the sponge  20  and may thus be secured thereto. The tethering member  25  may be inserted through the body of the sponge  20  by using a needle or by other insertion methods or structures known in the art. For example, a hole (not shown) may be punched through the body of the sponge  20  before inserting the tethering member  25 . As noted above, the tethering member  25  may have a first leg  27  and a second leg  29 , and that the first and second legs  27 ,  29  may be controlled by the user of the device  5  to manipulate the sponge  20 .  
      As shown in  FIG. 6 , the tethering member  25  may pass through the body of the sponge  20  twice so as to form a loop  65 . As described above, the tethering member  25  may be inserted through the body of the sponge  20 , and the loop  65  may thus be formed, by using a needle or by punching a hole through the sponge  20 . Passing the tethering member  25  through the sponge  20  twice may improve the user&#39;s ability to manipulate or remove the sponge  20 .  
       FIG. 7  illustrates an embodiment of the present disclosure in which a first and second tethering member  70 ,  71  may be used. In such an embodiment, the first and second tethering members  70 ,  71  may each pass through at least a portion of the sponge  20  and may be inserted thereto as described above. It is understood that the first tethering member  70  may have a first and second leg  75 ,  80  and that the second tethering member  71  may also have a first and second leg  76 ,  81 .  
      As shown in  FIG. 8 , however, the first and second legs  75 ,  80  of the first tethering member  70 , and the first and second legs  76 ,  81  of the second tethering member  71  may be crimped, knotted, or other wise attached to each other such that each of the tethering members  70 ,  71  may be controlled by manipulating a single leg. Although not shown, it is understood that greater than two tethering members  70 ,  71  may be used to manipulate the sponge  20 .  
      Referring back to  FIG. 1 , the first and second legs  27 ,  29  of the tethering member  25  may travel external to the device  5  and may enter the delivery tube  10  through a tethering member orifice  85 . In some embodiments, the delivery tube  10  may include more than one tethering orifice  85 , arranged circumferentially around the distal end  50  of the tube  10  with one or more of the legs  27 ,  29  extending therethrough. The first and second legs  27 ,  29  may then exit the distal end  50  of the delivery tube  10 . As will be described below, this path of travel may assist in removing the sponge  20 . Alternatively, the first and second legs  27 ,  29  of the tethering member  25  may travel internal to the delivery tube  10 , along the length of the tube  10 , until exiting the distal end  50  of the delivery tube  10  when the sponge  20  is deployed.  
      The device  5  of the present disclosure may be used to retrieve stones and other foreign matter located in the bladder, ureter, kidney or other body structure, and may be used in an environment that is relatively fluid filled, or that is relatively dry. The device  5  may be inserted through the urethra of the patient, or alternatively, the device  5  may be inserted percutaneously. It is understood that the device  5  may be used in any location of the body in which a passageway or orifice is being at least partially blocked by a foreign object.  
      The device  5  may be advanced to a treatment site in a number of different ways. For example, the device  5  may be advanced to the treatment site over a guidewire passing through all or a part of channel  30 . This treatment site may correspond to the vicinity of the stone  40  to be removed. The device  5  may also be advanced to the treatment site through an access sheath, or other access or dilatation device known in the art.  
      Alternatively, the device  5  may be fed to the treatment site fluoroscopically, and may travel through the body without the use of a guidewire or access sheath. To facilitate fluoroscopic feeding the delivery tube  10  may include radiopaque marker bands (not shown) detectable by x-ray. Thus, the user may utilize the urging member  15  to guide the delivery tube  10  to the treatment site and may monitor the position of the device  5  and movement thereof through the use of an x-ray monitor.  
      As yet another alternative, the device  5  may be used in conjunction with an endoscope (not shown), or other type of intracorporeal scope known in the art. The endoscope may travel through the body to the treatment site in any conventional manner. Once the endoscope is positioned adjacent to the treatment site, the delivery tube  10  may be fed to through an access port of the endoscope to gain access to the stone  40 .  
      As illustrated in  FIGS. 2-4 , to deliver the sponge  20 , the delivery tube  10  may be placed distal the stone  40 . The urging member  15  may then be held in place while the delivery tube  10  is retracted. The relative movement of the urging member  15  and the delivery tube  10  serves to deliver the sponge  20  distal the stone  40  in the approximate location of the urging member  15 . Alternatively, the delivery tube  10  may be placed distal the stone  40  and held in place while the urging member  15  is advanced, thereby urging the sponge  20  distal the stone  40 . This alternative, however, may not deliver the sponge  20  as precisely as the first method described above.  
      The hydrated sponge  20  may serve several purposes once it has been deployed. For example, the sponge  20  may be used to sweep a stone  40 . As described above, and as illustrated in  FIG. 4 , when placed into a liquid environment, the overall size of the sponge  20  may increase substantially due to fluid absorption. In its expanded state the sponge  20  may expand to conform to the section of the body structure into which it was delivered. The expanded sponge  20  may be soft enough not to damage the surrounding body tissue  45  while expanding, being manipulated within, or being removed from the body structure. In this state, the sponge  20  may also be rigid enough to sweep a stone  40  through the body structure for removal.  
      To sweep a stone  40  from the body, the user may position the sponge  20  distal the stone  40 . The sponge  40  may begin to absorb body fluid and may expand to fit the body structure. Once expanded, the user may pull the sponge  20  in a direction proximal the stone  40  by manipulating the first and second legs  27 ,  29  of the tethering member  25 . As used herein, the term “proximal” means closest to the user. The sponge  20  may then come into contact with a free-floating stone  40 , and urge the stone  40  in a proximal direction. Alternatively, if the stone  40  is impacted within the body tissue  45 , contact with the sponge  20  may dislodge the stone  40  and urge the stone  40  in the proximal direction. In this way, the sponge  20  may urge the stone  40  through the urinary tract until the stone reaches an exit of the body or a location that otherwise facilitates the removal of the stone from the body. This location may be the bladder or some other body structure allowing for the natural removal of the stone from the body. It is understood that if the sponge  20  contacts a small or sharp stone  40 , the stone  40  may become lodged within the surface of the sponge  20 . The stone  40  may then be carried with the sponge  20  as the sponge  20  travels in the proximal direction. Also, the sponge  20  may optionally be used to pin the stone  40  between the sponge  20  and the distal end of the delivery tube  10 . In such a situation, the delivery tube  10 , the sponge  20 , and the stone  40  may be removed as one unit if the stone  40  cannot be made to re-enter the delivery tube  10  with the sponge  20 .  
      During the sweeping process, the user may wish to release the stone  40 . For example, the stone  40  may encounter a restriction in the body tissue  45  while being swept through the urinary tract. Such a restriction might include, but is not limited to, swelling, scar tissue, or other stones or foreign matter. The restriction may be sized or positioned so as to impede the stone&#39;s  40  progress through the urinary tract, thereby necessitating releasing the stone  40  from the sponge  20 .  
      To release the stone  40 , the delivery tube  10  may be tracked over the first and second legs  27 ,  29  of the tethering member  25  until it is positioned distal the stone  40  and the restriction. The user may then pull on at least one of the first and second legs  27 ,  29  of the tethering member  25  to draw the sponge  20  into the distal end  50  of the delivery tube  10 . The sponge  20  may release at least some of the absorbed fluid before entering the delivery tube  10 . In some embodiments, a re-capture tube (not shown) of the device  5  may have a larger diameter than the delivery tube  10  to facilitate the re-capture of the expanded sponge  20 . The device  5  may then be retracted proximal the stone  40 . It is understood that the stone  40  may also be released by manipulating the tethering member  25  so as to discontinue contact between the sponge  20  and the stone  40 .  
      In addition to assisting in stone removal, the device  5  may also assist in immobilizing a stone  40  during stone reduction processes. Such processes may include laser lithotripsy, pneumatic stone reduction, or other processes known in the art. As illustrated in  FIG. 9 , these processes may involve the use of a laser fiber  35 , an air delivery device (not shown), or another device known in the art, to reduce the size of the stone  40  before it is removed from the body.  
      For example, as described above, the sponge  20  may be located distal a stone  40  so as to prevent small particles of the stone  40  from migrating or escaping from the treatment site during or after a laser fiber  35  or other device acts to break up the stone  40 . It is understood that the sponge  20  may be more resistant to damage from the laser fiber  35  than conventional wire baskets or stone retrieval devices. In addition, using a first and second tethering member  70 ,  71  may increase the dependability of the device  5 . For example, if the first tethering member  70  is accidentally severed during laser lithotripsy, the user may still be able to retrieve the sponge  20  using the second tethering member  71 .  
      As shown in  FIG. 9 , the urging member  15  may be removed from the delivery tube  10  once the sponge  20  has been deployed, and the laser fiber  35  may be fed to the stone  40  through the delivery tube  10 . Alternatively, the laser fiber  35  may be fed through the access port of an endoscope, external to the delivery tube  10 , while the delivery tube is disposed within the access port. As yet another alternative, the laser fiber  35  may be fed through a different access port of the endoscope than the delivery tube. It is understood that the laser fiber  35  may be activated and otherwise controlled by the user while it is within the body of the patient, and that a proximal end of the laser fiber  35  may connect to a power source (not shown).  
      Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. For example, the delivery tube  10  may include more than one tethering member orifice  85  and more than one channel  30 , and the device  5  may include more than one sponge  20 . Alternatively, the device  5  may utilize a web in conjunction with or instead of the sponge  20 .  
      In addition, the device  5  may also include a handle or an actuator operatively attached to the delivery tube  10 . Moreover, the at least one tethering member  25  may be attached to the sponge  20  with adhesives such as, for example, waterproof glue. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.