Abstract:
A method includes providing an inflatable implant formed of a flexible polymer material suitable for residence in the body. The implant includes a slit valve provided in its wall. The slit valve includes an elastomeric valve body with an open internal chamber being in fluid communication with a proximal opening of the valve, a concave section at its distal end, and a normally closed slit in a solid portion of the valve body connecting the concave section and the distal end of the valve body. An inflation tube having an injection tip with a distal end and an insertion stop is provided. The injection tip is inserted into the internal chamber of the slit valve until the insertion stop positively engages the proximal opening. Then, the implant with the inflation tube is delivered to a body cavity. Once delivered, fluid is introduced through the inflation tube and into the implant.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 13/667,617, filed Nov. 2, 2012, which is a divisional of U.S. patent application Ser. No. 12/785,710, filed May 24, 2010, now abandoned, which is a continuation of U.S. patent application Ser. No. 10/561,515, filed Dec. 20, 2005, now U.S. Pat. No. 7,749,254, which is a national stage application under 35 U.S.C. §371 of PCT Patent Application No. PCT/US2003/019414, filed Jun. 20, 2003, each of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is directed to a slit valve that enables two-way fluid flow, and in particular a slit valve for use with implantable, inflatable medical devices such as gastric balloons for the treatment of obesity. 
         [0004]    2. Description of the Related Art 
         [0005]    There are a wide variety of known inflatable devices that can be implanted in the body. One such inflatable implantable medical device is a gastric balloon, as described in U.S. Pat. No. 5,084,061, or commercially available as the BioEnterics Intragastric Balloon System (sold under the trademark BIB®). These devices are designed to provide therapy for moderately obese individuals who need to shed pounds in preparation for surgery, or as part of a dietary or behavioral modification program. 
         [0006]    The BIB System, for example, consists of a silicone elastomer gastric balloon that is inserted into the stomach and filled with fluid. Commercially available gastric balloons are filled with saline solution or air. The gastric balloon functions by filling the stomach and enhancing appetite control. Placement of the gastric balloon is non-surgical, usually requiring no more than 20-30 minutes. The procedure is performed endoscopically in an outpatient setting, using local anesthesia and sedation. Placement is temporary, and gastric balloons are typically removed after six to twelve months. 
         [0007]    There are known in the prior art a variety of valves for use with such gastric balloons. For example, the valve described in U.S. Pat. No. 5,084,061, shown in  FIG. 1 , consists essentially of a leaf valve (also known as a duckbill valve) comprising two relatively flat pieces of silicone elastomer bonded along their longitudinal edges and affixed by adhesive to the end of the valve stem. In operation, a filler tube, which is usually a plastic or silicone tube containing a stainless steel stiffening rod, is inserted through an X-shaped slot, through a hole, through a tubular valve stem, through a second X-shaped slot in the membrane, and through the leaf valve until the filler tube itself is in the interior of the shell. In such a position, both addition and withdrawal of fluid can be accomplished. For addition of fluid only, the filler tube does not need to penetrate through the leaf valve. 
         [0008]    However, valves of this sort have several disadvantages. Initially, these valves are prone to leaking One way in which a duckbill valve may develop leaks is through the initial filling of the balloon when one of the flat pieces of elastomer becomes kinked or develops a curvature through which the fluid can pass. Another way is through the fluid removal process, which requires the insertion of the filler tube completely through the valve and into the interior of the shell. Following removal of a portion of the fluid and the filler tube, the leaf valve can remain partially open. This causes even greater amounts of the fluid to be released from the implant. Accordingly, there is a need for a valve that does not leak following either filling or removal of fluid from the shell. 
         [0009]    Second, the prior art leaf valves face opposing problems in that it is necessary to reduce the pressure necessary to insert the filler tube into the valve to ease in installation and filling, but if there is not a sufficiently tight fit between the filler tube and the valve, then the pressure of the fluid in the balloon or valve may force the filler tip out of the valve before filing is complete. Further, it is necessary to consider the amount of force necessary to remove the fill tube from the valve. Current designs, such as that discussed above, often require too much pressure to insert the filler tube into the valve and too much pressure to remove the filler tube from the valve. Alternatively, in instances where the pressure necessary to insert and remove the filler tube are not great, the filler tube may pop out of the valve while filling the balloon. Accordingly, there is a need for a valve that promotes easy insertion and removal of the filler tube, but does not force the filler tube out of the valve while filling the balloon. Prior art leaf valves are also unsuitable at fluid inflation pressures above 30 psi, which may damage the valve. 
         [0010]    Finally, the prior art duckbill valves have the shortcoming that they are only one-way valves. They cannot be used to direct fluid flow in both directions without inserting a tube completely through the valve. Situations arise where it is preferable to have a two-way valve. For example, when a device absorbs additional fluid through osmosis after being implanted in the body and filled to a proper volume, it may be desirable to reduce the fluid volume of that implant. In the duckbill valve described above, no amount of pressure on the interior of the balloon will permit egress of the fluid contained therein. Accordingly, there is a need to a valve that is capable, of permitting back flow of fluid (i.e., from the interior to the exterior), while generally preventing egress of fluid when under normal pressure. 
         [0011]    Another type of valve often used in implant technology is a diaphragm valve, such as a that discussed in U.S. Pat. No. 6,419,699 assigned to McGhan Medical Corporation. The diaphragm valve requires insertion of a rigid male component on the inflation tube to open the valve and allow fluid transfer. Upon removal of the inflation tube, fluid pressure within the implant forces the valve closed and creates a leak proof seal. As with the leaf valve, such a valve does teach any means for backflow through the valve. 
         [0012]    Other valves that are used in medical applications include a connector for an instrument insertion passage described in U.S. Pat. No. 5,599,327 (“the &#39;327 patent”), a non-binding surgical valve as described in U.S. Pat. No. 5,916,198 (“the &#39;198 patent”), and a needle less injection site as described in U.S. Pat. No. 6,261,268 (“the &#39;268 patent”). Each of these valves or connectors has shortcomings that are addressed by the present invention. Initially, both the &#39;327 and the &#39;268 patents contemplate an opening in the valve that forms a seal with the application of mechanical pressure by a medical instrument. Accordingly, both the &#39;327 and &#39;268 patents require the use of bulky components and mechanical force to create a seal. Such components and use of mechanical force are not conducive for use with implant technology. Further, the &#39;198 patent describes a one-way valve that is closed by insufflation gases acting on an interior surface of the valve via a passage in one of the valve segments. Accordingly, the valve contemplated by the &#39;198 patent does not overcome the shortcomings of the prior art discussed above. Therefore, the present invention is directed at overcoming these problems associated with the prior art valves. The present invention is related to a two-way valve that is usable in an implantable medical device such as a gastric balloon. These and other characteristics of the present invention will become apparent from the further disclosure to be made in the detailed description given below. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention is directed to a two-way valve having first and second ends. The two-way valve includes a substantially cylindrical valve body having a slit connecting the first and second ends of the valve and concave sections formed in the first and second ends. 
         [0014]    The present invention is further directed to a slit valve having a flange surface with an opening therein. The slit valve has a valve body connected to the flange surface and a chamber formed in the valve body for accepting an inflation tube inserted through the opening in the flange surface. The slit valve has a concave section at one or both ends, which are connected by a slit formed in the valve body. 
         [0015]    The present invention is also directed to an implantable, inflatable apparatus having a slit valve. The slit valve includes a flange surface having an opening. The slit valve also includes a valve body connected to the flange surface, a first chamber formed in the valve body for accepting an inflation tube inserted through the opening in the flange surface, a concave section located at one or both ends of the valve, and a slit formed in the valve body connecting the two ends. 
         [0016]    The present invention is also directed to a medical apparatus for the treatment of obesity. The medical apparatus includes a balloon formed of a suitable polymer or elastomer material for insertion into the stomach, and a slit valve for communication of a fluid from an inflation tube to the balloon. The slit valve includes a flange surface having an opening therein, a valve body connected to the flange surface, a first chamber formed in the valve body for accepting the inflation tube inserted through the opening in the flange surface, a concave section located at one or both ends of the valve, and a slit formed in the valve body connecting the two ends. 
         [0017]    Further characteristics, features, and advantages of the present invention will be apparent upon consideration of the following detailed description of the invention take in conjunction with the following drawings, and in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a cross sectional view of a prior art gastric balloon with a one-way valve; 
           [0019]      FIG. 2  is a cross-sectional view of a prior art one-way valve; 
           [0020]      FIG. 3  is a side view of a two-way slit valve according to one of the embodiments of the present invention; 
           [0021]      FIG. 4  is a cross-sectional view of the two-way valve shown in  FIG. 3 ; 
           [0022]      FIG. 5  is a close-up view of a portion of the two-way valve shown in  FIG. 4 ; 
           [0023]      FIG. 6  is a top view of the two-way valve according to another aspect of the present invention; 
           [0024]      FIG. 7  is side view of a filler-tube according to another aspect of the present invention; 
           [0025]      FIG. 8  is a side view of an inflation tip according to another aspect of the present invention; 
           [0026]      FIG. 9  is a cross-sectional view of the inflation tip of  FIG. 8 ; and 
           [0027]      FIG. 10  is a cross-sectional view of a two-way valve according to another aspect of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    A slit valve  10  in accordance with a first embodiment of this invention is shown in  FIG. 3 . The valve comprises a valve body  14  and a flange  12 . With respect to the description of this invention, the end of the valve  10  on which the flange  12  is located will be called the top of the valve and the opposite end the bottom. The valve  10  is preferably formed of an elastomeric material such as silicone; however, other materials may be used without departing from the scope of this invention. The valve body  14  is preferably molded in a substantially cylindrical shape. The cylindrical shape is preferred as it provides added rigidity and stiffness for the valve. 
         [0029]      FIGS. 4 and 5  show cross-sectional views of the valve  10 .  FIG. 6  shows a top view of valve  10 . Starting at the flange surface  12  of the top of the valve  10 , there is an opening  16  through the flange  12  that is in communication with interior surfaces of the valve  10 . Immediately below the opening  16  is a first chamber  18 . Beneath the first chamber  18  is a neck  19 . The neck  19  separates the first chamber  18  from a second chamber  26 . At the bottom of the second chamber is a concave surface  20 . The concave surface  20  is preferred because it provides guidance to a probe in the event that the sealing properties of valve  10  need to be overcome mechanically. The concave surface  20  assists in the guidance of a probe (not shown) that can be used to force the valve to open and allow for reverse flow of fluid contained by the valve  10 . 
         [0030]    Following the concave surface  20  is a slit  24  in a substantially solid portion of the body  14 . The slit  24  connects and is in fluid communication with a second surface  22 , which may be concave as shown, or flat. In an application such as a gastric balloon, fluid enters the balloon shell as it exits the bottom side of the slit  24 . The slit  24  may be lubricated with silicone oil. The use of silicone oil eases the insertion of a removal tip (not shown) in instances where it is desired to overcome the sealing properties of the valve  10 , and serves to reduce the chance of cross-linking where the valve body  14  is made of silicone. 
         [0031]      FIG. 7  depicts a filler tube  30 . The filler tube is comprised of a long flexible tube  34  having a lumen therethrough, an injection tip  32 , and a connector  35  for connecting the filler tube to a fluid supply (not shown). The flexible tube  34  may be provided with reference length markers  36  to provide medical personnel with a visual indication of the position of fill tube  30  inside the patient. As shown in  FIGS. 8 and 9 , the injection tip  32  has an orifice  37  extending therethrough that allows for fluid communication through the flexible tube  34 , and the injection tip  32 . One of the ends of the injection tip may be tapered into a wedge shape  38  having its smallest cross-section at the distal end of the injection tip  32 . The wedge shape  38  assists in the insertion of the injection tip  32  into slit valve  10 . Further, the injection tip may include a reduced diameter portion  40 , and an insertion stop  42  for positively engaging the opening  16  of valve  10 . The other end of the injection tip  32  is provided with barbs  44  to retain flexible tube  34  in fluid-tight engagement with the injection tip. 
         [0032]    In use, the filler tube  30  is connected to the valve  10  by inserting the injection tip  32  into opening  16  of the valve  10 . The injection tip  32 , upon full insertion into the valve, extends to a point approximately even with a top surface of the second chamber  26 . The substantial wedge shape  38  of the injection tip matches the orientation of the first chamber  18 , and the narrow cross-sectional portion of the injection tip  32  is held firmly by the neck  19  of valve  10  to form a seal preventing the egress of fluid from the second chamber  26  into the first chamber  18  and out through the opening  16 . The insertion stop  42  on the injection tip  32  prevents the injection tip from being inserted into the valve  10  beyond a pre-determined point. Upon full insertion, the insertion stop  42  rests against the flange  12  of valve  10 . The opening  16  is of a size that, upon insertion of the injection tip  32 , a second seal is formed by the interference of the flange  12  and the reduced diameter portion  40  of the injection tip. This second seal further insures that fluid does not exit the valve  10  and prevents other contaminants from entering the valve  10 . 
         [0033]    The valve  10  may be attached to an inflatable medical device such as a gastric balloon, a mammary implant, such as a Becker-style breast implant, a tissue expander, or the like. Other non-inflatable applications of the valve include devices such as a shunt drug delivery or therapeutic delivery system, a feeding tube, or the like. Accordingly, these variations are contemplated within the scope of the present invention. Where the device is a gastric balloon, the valve  10  is attached to the shell substantially as shown in Prior Art  FIGS. 1 and 2 . The flange surface  12  is placed flush with the exterior surface of the balloon and may be covered by an elastomeric sheath material that bonds the components together forming an integral gastric balloon and valve combination. The gastric balloon is inserted into a patient in a deflated state and inflated after insertion. Following insertion of the gastric balloon, a fluid, typically sterile saline, is injected into the gastric balloon via the filler tube  30 . Other fluids, including air, silicone, pseudogel, oil, etc., may be used to fill an implant. 
         [0034]    To inflate the gastric balloon, the valve  10  must have a slit  24 . The slit  24  is preferably a single separation of two sides of the valve body  14 . The slit  24  is formed during manufacturing by inserting a sharp thin tool (not shown) into the valve body  14 . The length of the slit  24  is variable depending on the application of the valve and the desired opening pressure of the valve. In certain applications it may be necessary to insure that slit valve permits backflow more readily. In such instances, a shorter slit length would be used, whereas in instances where greater pressure must be contained by the valve, a longer slit length is desirable. 
         [0035]    To effectuate inflation via the filler tube  30 , the injection tip  32  is inserted into the opening  16  of the flange  12 . The distal end of injection tip  32  extends to form a seal with neck  19 . When pressurized fluid is injected through the filler tube  30  and orifice  37  of the injection tip  32 , a higher pressure is created in the second chamber  26  having two effects. The first is to increase the sealing pressure of the neck  19  on the injection tip  32 . The second effect is to force the slit  24  to open. The decreased wall thickness of the valve body  14  in the area of the second chamber  26  is more readily deformed by the pressurized fluid injected into the second chamber  26  than the area of the slit  24 . The increased pressure causes the second chamber  26  to expand in a direction substantially perpendicular to the direction of the slit  24 . This expansion in turn causes the slit  24  to be opened and permits the flow of fluid from the second chamber  26  through the slit  24  and into the implant. The opening of the slit is assisted by the concave surface  20 . Similarly, if the second surface  22  is also concave, sufficient pressure may be applied to the shell to overcome the backflow resistance of the valve to permit the flow of fluid through the slit  24  to the exterior of the implant. Due to the relative sizes of the second chamber  26  and the concave surface  22 , a far greater pressure is required to permit the backflow of fluid from the implant out of the valve than is required for inflation. For this reason the balloon or other implant may also be deflated or reduced in volume by inserting a small diameter probe or tube completely through the valve and into the interior of the implant shell. Concave surface  20  assists in guiding the small-diameter probe or tube into and through the valve body  14 . 
         [0036]    The valve  10  and the filler tip  32  when used in combination create a system that overcomes many of the shortcomings of the prior art. Through the use of the opening  16  and its interaction with the reduced diameter portion  40  of the injection tip  32 , and also because of the interaction of the neck  19  with the injection tip  32 , the injection tip is held firmly in place and is prevented from being forced out of the valve  10  during the injection of fluid through the valve  10 . Further, because of these same features, withdrawal of the injection tip  32 , when desired by the user, is greatly eased requiring less than 4 lb (17.8 N) of force to remove the tip from a balloon filled to 700 cm 3 . Still further, the valve  10  provides for a device that does not leak under normal operating conditions yet still allows for two-way flow. The valve of the present invention allows continuous fluid flow at 30 psi (2.11 Kg/cm2) and can safely withstand fluid fill pressures of up to 40 psi (2.81 Kg/cm 2 ) without damage to the valve. 
         [0037]      FIG. 10  depicts another aspect of the present invention.  FIG. 10  shows a valve  11  having many of the features of the valve  10  shown in  FIGS. 3-6 . Valve  11  has a first concave surface  20 , a second concave surface  22 , and a slit  24 , all housed in a body  14 . The valve  11  operates in a similar fashion to valve  10 . Upon application of a predetermined fluid pressure to one of either the first or second concave surfaces,  20  or  22 , the slit  14  will open and allow fluid to pass. However, at pressures below the predetermined value, the slit valve insures that there is no fluid flow. The relative geometries of the concave surfaces  20 ,  22 , the length of the slit  24 , and the valve body  14  determine the opening pressure of the valve  11  and whether a greater pressure is required for flow in one direction compared to flow in the other direction. Such a valve would be useful in applications where the use of a flange  12 , as shown in  FIG. 3 , is undesirable or unfeasible, for example in a feeding tube or a drug delivery shunt. 
         [0038]    Although the invention has been particularly shown and described with reference to certain preferred embodiments, it will be readily appreciated by those of ordinary skill in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention.