Patent Publication Number: US-2019192272-A1

Title: Gallbladder implants and systems and methods for the delivery thereof

Description:
RELATED APPLICATION/S 
     This application claims the benefit of priority under PCT Article 8 of U.S. patent application Ser. No. 15/147,080 filed on May 5, 2016, and is related to PCT application PCT/IL2015/051051, filed on Oct. 27, 2015, which claims the benefit of priority under PCT Article 8 of Provisional Patent Application No. 62/069,164 filed Oct. 27, 2014; this application is also related to pending U.S. patent application Ser. No. 15/140,505 filed on Apr. 28, 2016, and PCT application PCT/IL2017/050384 filed on Mar. 28, 2017, the contents of all of which are incorporated by reference herein in their entireties. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates generally to treating medical conditions involving ducts and/or body lumens, for example by preventing occlusion of portions of the biliary tree during treatment device deployment. 
     “Stones” in the gallbladder and bile ducts are found in the entire population, some of them being asymptomatic, and some—symptomatic. In the U.S., 10-15% of the adult population (more than 20 million people) suffer from bile duct stones (about 20% of the population above 65 years of age suffer from gallstones), with more than two million new cases diagnosed annually, and more than 1,800,000 cholecystectomy procedures performed annually. Patients with gallstones are classified according to three groups: symptomatic, asymptomatic and those suffering from complications caused by the gallstones, such as cholecystitis, pancreatitis or obstructive jaundice. 
     SUMMARY OF THE INVENTION 
     There is provided in accordance with an exemplary embodiment of the invention, a filter device for implantation in a gallbladder, comprising: a filtering portion configured to filter gallstones of a certain minimum size to prevent them from exiting the gallbladder through an opening of the gallbladder; a tail extending from the filtering portion away from the opening of the gallbladder and towards a distal wall of the gallbladder; and, a stopper located at a distal end of the tail, near the distal wall of the gallbladder when the filter device is implanted; wherein the filtering portion, stopper and the tail are configured to be of sufficient overall length within the gallbladder that they, when taken together, prevent migration of the filtering portion away from the opening of the gallbladder. 
     In an embodiment of the invention, the filtering portion, tail and stopper are configured to fit entirely and substantially uncompressed within the gallbladder. 
     In an embodiment of the invention, the filtering portion is comprised of spherical, circular, ovoid or oblong leaves. 
     In an embodiment of the invention, at least some of the leaves overlap at least partially. 
     In an embodiment of the invention, the stopper is split into at least two tails, each tail configured with its own stopper. 
     In an embodiment of the invention, the stopper is mushroom-shaped, biased towards the opening of the gallbladder. 
     In an embodiment of the invention, the stopper is coil-shaped. 
     In an embodiment of the invention, the stopper is resilient. 
     In an embodiment of the invention, the stopper is configured with at least two concentric circles. 
     In an embodiment of the invention, the filter device is comprised of a single filament. 
     In an embodiment of the invention, two loose ends of the single filament are attached together. 
     In an embodiment of the invention, the two loose ends are welded together. 
     In an embodiment of the invention, the filter device is configured such that the two loose ends are attached together along the tail. 
     In an embodiment of the invention, the device is made from at least one of a metal, a shape memory alloy and a polymer. 
     In an embodiment of the invention, the device is adapted for eluting a pharmaceutical after implantation. 
     In an embodiment of the invention, the device is at least one of bioabsorbable and biodegradable. 
     In an embodiment of the invention, at least one of the stopper and filtering portion are configured to prevent bio-film growth. 
     In an embodiment of the invention, the filtering portion is configured to filter gallstones 5 mm or greater in diameter. 
     In an embodiment of the invention, the stopper is configured to push gallstones of a certain minimum size away from the opening of the gall bladder. 
     There is further provided in accordance with an exemplary embodiment of the invention, a system for delivery of a filter device for implantation in a gallbladder, comprising: a filter device including a stopper; a guiding rod around which the filter device is at least partially wrapped; and, a catheter with an opening at a distal end, through which the guiding rod and filter device are inserted, configured for transit to the gallbladder. 
     In an embodiment of the invention, the filter device is wrapped on a side of the guiding rod, such that the filter device is deployable in the gallbladder without retraction of the guiding rod. 
     There is further provided in accordance with an exemplary embodiment of the invention, a method for implanting a filter device in a gallbladder, comprising: navigating the filter device wrapped around a guiding rod through an opening to the gallbladder for implantation, the filter device including at least a filtering portion, a tail and a stopper; withdrawing at least partially a catheter, through which the guiding rod and filter device are inserted, from the implantation site; expanding at least a portion of the filter device at least partially; and, withdrawing the guiding rod from the implantation site, leaving the expanded filter device entirely within the gallbladder and substantially uncompressed, wherein the filtering portion is disposed proximal to the opening of the gallbladder and the stopper is disposed proximal to a distal wall of the gallbladder opposite the opening after implantation. 
     In an embodiment of the invention, the expanding includes expanding the stopper then pushing gall stones towards the distal wall prior to expanding of the filtering portion. 
     In an embodiment of the invention, the pushing is performed by at least one of the guiding rod and the stopper. 
     In an embodiment of the invention, the filter device is implanted such that an attachment between two loose ends of the single filament filter device does not abut a wall of the gallbladder. 
     There is further provided in accordance with an exemplary embodiment of the invention, a filter device for implantation in a gallbladder, comprising: a filtering portion configured with a plurality of at least partly overlapping leaves to prevent gallstones of a certain minimum size from exiting the gallbladder through an opening of the gallbladder; at least one tail extending from the filtering portion away from the opening of the gallbladder and towards a distal wall of the gallbladder; and, at least one stopper located at a distal end of the at least one tail, near the distal wall of the gallbladder when the filter device is implanted; wherein the filtering portion, stopper and the tail are configured to be of sufficient overall length within the gallbladder that they, when taken together, prevent migration of the filtering portion away from the opening of the gallbladder, and, wherein the filter device is constructed of a single wire with two loose ends attached together. 
     There is further provided, a method of deploying a filtering device in a gallbladder, comprising: navigating a guide wire to an implantation site in the gallbladder; placing an external catheter containing the filtering device over the guide wire; advancing the external catheter and the filtering device in a distal direction along the guide wire to the implantation site; and, deploying at least a blocking portion of the filtering device out of the external catheter. 
     In an embodiment of the invention, the deploying includes pushing at least one gall stone away from a gallbladder opening towards a distal wall of the gallbladder with the blocking portion. 
     In an embodiment of the invention, placing further comprises placing over the guide wire, a tip on the distal end of the external catheter. 
     In an embodiment of the invention, the advancing further comprises using the tip to assist with the advancing to the implantation site. 
     In an embodiment of the invention, the method further comprises using medical imaging to image the guide wire and verify proper placement of the guide wire at the implantation site. 
     In an embodiment of the invention, the method further comprises retracting the external catheter to deploy at least the blocking portion of the filtering device. 
     In an embodiment of the invention, the method further comprises withdrawing everything but the filtering device from the gallbladder. 
     There is further provided, a filtering device for implantation in a gallbladder, comprising: an egg or ovoid shaped body configured to transition from a collapsed configuration to an expanded egg or ovoid shaped configuration; wherein the body is formed from at least one egg or ovoid shaped coil of wire forming an interior space within the coil for trapping gall stones. 
     In an embodiment of the invention, the body does not exert pressure, in the expanded configuration, on a wall of the gallbladder. 
     In an embodiment of the invention, the filtering device is comprised of a single wire. 
     In an embodiment of the invention, the coil of wire is denser on a proximal end of the filtering device near an opening of the gallbladder. 
     In an embodiment of the invention, the coil of wire is continuous. 
     In an embodiment of the invention, two ends of a linear coil of wire are welded together to form the ovoid or egg shape. 
     In an embodiment of the invention, the coil of wire is 0.05 mm-0.35 mm thick. 
     In an embodiment of the invention, the filtering device further comprises an internal blocking portion disposed in the interior space of the filtering device. 
     In an embodiment of the invention, the filtering device is comprised of a single wire. 
     In an embodiment of the invention, the internal blocking portion is egg or ovoid shaped. 
     In an embodiment of the invention, the filtering device further comprises a mesh structure disposed on a proximal side of the filtering device near a gallbladder opening. 
     In an embodiment of the invention, the mesh structure comprises a plurality of leaf or petal shapes. 
     In an embodiment of the invention, the body is formed from a plurality of wires, the ends of which are joined together by at least one joining ring. 
     In an embodiment of the invention, the filtering device further comprises at least one indentation formed by a curvature of the wires. 
     There is further provided, a filtering device deployment system, comprising: an external catheter formed in a hollow cylindrical shape; a central cylinder configured for insertion into and through the external catheter; a filtering device; and, a release wire, biased to be straight, disposed near a distal end of the central cylinder and within the external catheter, wherein the release wire is releasably hooked around a portion of the filtering device to retain the filtering device within the external catheter. 
     In an embodiment of the invention, the filtering device deployment system further comprises a ring disposed near and around the distal end of the central cylinder. 
     In an embodiment of the invention, the release wire is attached to the ring. 
     Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example, and not necessarily to scale, and are for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced. 
       In the drawings: 
         FIGS. 1A-1E  are side views of a schematic deployment sequence of a blocking device, in accordance with an exemplary embodiment of the invention; 
         FIGS. 2A-2C  are side views of a schematic deployment sequence of a filtering device after the blocking sequence shown in  FIGS. 1A-1E  has been performed, in accordance with an exemplary embodiment of the invention; 
         FIGS. 3A-3C  are side views of two tier filtering devices, in accordance with exemplary embodiments of the invention; 
         FIGS. 4A-4C  are top views of the filtering portion of filtering devices, in accordance with exemplary embodiments of the invention; 
         FIGS. 5A and 5B  are perspective views of a filtering device, in accordance with an exemplary embodiment of the invention; 
         FIG. 5C  is a side view of a filtering device delivery system, in accordance with an exemplary embodiment of the invention; 
         FIG. 5D  is a side view of a filtering device delivery system with the filtering device partially deployed, in accordance with an exemplary embodiment of the invention; 
         FIG. 6  is a top view of a filtering device in situ, in accordance with an exemplary embodiment of the invention; 
         FIG. 7  is a flowchart of a method of deploying a filtering device in a gallbladder, in accordance with an exemplary embodiment of the invention; 
         FIG. 8  is a flowchart of a method of deploying a filtering device in a gallbladder, in accordance with an exemplary embodiment of the invention; 
         FIG. 9A  is a side view of a filtering device with dense leaves and a split stopper, in accordance with an exemplary embodiment of the invention; 
         FIG. 9B  is a side view of a filtering device with large overlapping leaves, in accordance with an exemplary embodiment of the invention; 
         FIGS. 10A-10C  are side views of different stopper configurations, in accordance with exemplary embodiments of the invention; 
         FIGS. 11A-11C  are side views of a schematic deployment sequence of a filtering device, in accordance with exemplary embodiments of the invention; 
         FIG. 12  is a side view of an egg-shaped filtering device, in accordance with exemplary embodiments of the invention; 
         FIG. 13  is a side view of a double layered egg-shaped filtering device, in accordance with exemplary embodiments of the invention; 
         FIG. 14  is a side view of an asymmetrically meshed egg filtering device, in accordance with exemplary embodiments of the invention; 
         FIGS. 15A-15B  are side views of ringed, egg-shaped filtering devices, in accordance with exemplary embodiments of the invention; 
         FIG. 16  is a side view of a two layered filtering device, in accordance with exemplary embodiments of the invention; 
         FIGS. 17A-17D  are side views of a schematic deployment sequence of a filtering device, in accordance with exemplary embodiments of the invention; 
         FIG. 18  is a flowchart of a method of deploying of a filtering device, in accordance with an exemplary embodiment of the invention; 
         FIG. 19  is a plan view of at least a part of a filtering device, in accordance with an exemplary embodiment of the invention; 
         FIG. 20A-20C  are side views of filtering devices, in accordance with some exemplary embodiments of the invention; and, 
         FIGS. 21A-21B  are plate and tube cutting patterns for filtering devices, in accordance with exemplary embodiments of the invention. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
     The present invention relates generally to treating medical conditions involving ducts and/or body lumens, for example by preventing occlusion of portions of the biliary tree during treatment device deployment. 
     In an aspect of the invention, there is provided a filter device for implantation in a gallbladder, comprising: a filtering portion configured to filter gallstones of a certain minimum size to prevent them from exiting the gallbladder through an opening of the gallbladder; a tail extending from the filtering portion away from the opening of the gallbladder and towards a distal wall of the gallbladder; and, a stopper located at a distal end of the tail, near the distal wall of the gallbladder when the filter device is implanted; wherein the filtering portion, stopper and the tail are configured to be of sufficient overall length within the gallbladder that they, when taken together, prevent migration of the filtering portion away from the opening of the gallbladder. 
     In an aspect of the invention, there is provided a system for delivery of a filter device for implantation in a gallbladder, comprising: a filter device including a stopper; a guiding rod around which the filter device is at least partially wrapped; and, a catheter with an opening at a distal end, through which the guiding rod and filter device are inserted, configured for transit to the gallbladder. 
     In an aspect of the invention, there is provided a method for implanting a filter device in a gallbladder, comprising: navigating the filter device wrapped around a guiding rod through an opening to the gallbladder for implantation, the filter device including at least a filtering portion, a tail and a stopper; withdrawing at least partially a catheter, through which the guiding rod and filter device are inserted, from the implantation site; expanding at least a portion of the filter device at least partially; and, withdrawing the guiding rod from the implantation site, leaving the expanded filter device entirely within the gallbladder and substantially uncompressed, wherein the filtering portion is disposed proximal to the opening of the gallbladder and the stopper is disposed proximal to a distal wall of the gallbladder opposite the opening after implantation. 
     In an aspect of the invention, there is provided a filter device for implantation in a gallbladder, comprising: a filtering portion configured with a plurality of at least partly overlapping leaves to prevent gallstones of a certain minimum size from exiting the gallbladder through an opening of the gallbladder; at least one tail extending from the filtering portion away from the opening of the gallbladder and towards a distal wall of the gallbladder; and, at least one stopper located at a distal end of the at least one tail, near the distal wall of the gallbladder when the filter device is implanted; wherein the filtering portion, stopper and the tail are configured to be of sufficient overall length within the gallbladder that they, when taken together, prevent migration of the filtering portion away from the opening of the gallbladder, and, wherein the filter device is constructed of a single wire with two loose ends attached together. 
     In an aspect of the invention, there is provided a method of deploying a filtering device in a gallbladder, comprising: navigating a guide wire to an implantation site in the gallbladder; placing an external catheter containing the filtering device over the guide wire; advancing the external catheter and the filtering device in a distal direction along the guide wire to the implantation site; and, deploying at least a blocking portion of the filtering device out of the external catheter. 
     In an aspect of the invention, there is provided a filtering device for implantation in a gallbladder, comprising: an egg or ovoid shaped body configured to transition from a collapsed configuration to an expanded egg or ovoid shaped configuration; wherein the body is formed from at least one egg or ovoid shaped coil of wire forming an interior space within the coil for trapping gall stones. 
     In an aspect of the invention, there is provided a filtering device deployment system, comprising: an external catheter formed in a hollow cylindrical shape; a central cylinder configured for insertion into and through the external catheter; a filtering device; and, a release wire, biased to be straight, disposed near a distal end of the central cylinder and within the external catheter, wherein the release wire is releasably hooked around a portion of the filtering device to retain the filtering device within the external catheter. 
     Generally, systems, devices and methods for deploying filtering devices in a gallbladder and filtering devices themselves are described. In some aspects of the invention, a blocking device and/or a blocking portion of a device are used to push gall stones away from the opening to the gallbladder in order to make space for proper deployment of a gall stone filtering device. In some embodiments of the invention, the blocking device and the filter device are components of a system. In some embodiments of the invention, the blocking device is separate from the filtering device. In some embodiments of the invention, the blocking is performed by a filtering portion of the filtering device. In some embodiments of the invention, the filtering device is two-tiered. Optionally, one tier is configured to block and/or filter. Optionally, one tier is configured to anchor the device. In some embodiments of the invention, the device is provided with a stopper, optionally on a distal end of a tail, wherein the tail, the stopper and/or the filtering/blocking section prevent substantial migration of the filter device away from an opening to the gallbladder. 
     In an aspect of some embodiments of the invention, some or all of a gallbladder filter device is constructed of a single wire or filament. In an embodiment of the invention, the single wire filter device is manufactured by placing a plurality of bends or curves in the wire (for example, forming the leaves of a filter portion and/or the curvature of a stopper). Optionally, the filter device is completed by attaching two loose ends of the wire together, for example by welding. It should be understood that an advantage of a single wire device is that there results in only one seam in the device which needs to be closed, representing an advantage in manufacturing. 
     It should also be understood that since seams may be more traumatic to body tissue than the rest of the device (which is probably smoother), the fewer the number of seams the better from a patient health and/or device utilization standpoint. In some embodiments of the invention, the junction between the two loose ends, which are attached to each other, occurs along a portion of the filter device that will not abut body tissue. In an embodiment of the invention, the filter device is implanted in the patient such that the seam is not proximal to, or does not abut, body tissue. 
     In some aspects of some embodiments of the invention, the devices described herein spare the patient from suffering and/or surgery, and are intended to prevent the complications of cholecystectomy and anesthesia, operative mortality, postoperative infections (wound infection and other infections), and/or delayed impacts of gallbladder absence (impaired absorption, abdominal pain, etc.) by relieving and/or preventing the symptoms of cholecystitis, pancreatitis or obstructive jaundice, and/or preventing and/or delaying the need for cholecystectomy in patients with gallstones. In some embodiments of the invention, temporary relief, for example of pain induced by gallstones, is provided. 
     It should be understood that exemplary filter devices described herein are intended to prevent gallstones from passing from the gallbladder into the cystic duct while still allowing for normal bile flow and/or bodily fluids and/or secretions through the biliary tree and into the duodenum. In some exemplary embodiments of the invention, filtering is achieved without exerting potentially harmful levels of expansive radial force on the walls of the cystic duct and/or gallbladder. In some embodiments of the invention, no radial force is applied on the walls of the cystic duct and/or gallbladder. 
     Throughout the description, “proximal” or “proximally” means in the direction closest to outside of the patient&#39;s body and “distal” or “distally” means in the opposite direction, that is in the direction further into the patient&#39;s body. 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. 
       FIGS. 1A-1E  are side views of a schematic deployment sequence of a blocking device  100 , in accordance with an exemplary embodiment of the invention. For efficiency, description of device embodiments of the invention ( FIGS. 1A-1E  and  FIGS. 2A-2C ) are described in conjunction with the methods of their deployment, in conjunction with  FIG. 7 . 
       FIG. 7  is a flowchart  700  depicting a method of implanting a filter device  200  in the gallbladder  104 , in accordance with an embodiment of the invention. In an embodiment of the invention, implantation may be performed without general anesthesia and is considered to be minimally invasive. In an embodiment of the invention, the filter device  200  and/or the blocking device  100  are inserted and/or navigated ( 702 ) into the GI tract via the mouth, through to the esophagus, through to the stomach and then into the duodenum. Navigation and/or insertion are accomplished using an endoscope and/or a flexible guide wire/guiding rod and/or an elongated tool, such as a catheter  106 , as chosen by the attending medical professional performing the procedure, in an embodiment of the invention. 
     The filter device  200  is advanced the Sphincter of Oddi/papila into the common bile duct, in an exemplary embodiment of the invention. A sphincterotomy of the Sphincter of Oddi is performed, if required and/or desired, similarly to the method commonly used in endoscopy and ERCP. The filter device  200  is implanted at a desired implantation site by navigating the filter device  200  from the common bile duct through to the cystic duct and/or the gallbladder  104 . Contrast material in used order to image the gallbladder  104  and/or the cystic duct and/or the gastro-intestinal tract, in some exemplary embodiments of the invention. Optionally, other commonly available imaging techniques are used for the implantation, for example X-ray and/or ultrasound. 
     In an exemplary embodiment of the invention, the filter device  200  and/or the blocking device  100  are inserted and/or navigated ( 702 ) into the patient in a contracted form. In some embodiments of the invention, the blocking device  100  precedes the filter device  200  such that during implanting, the blocking device  100  enters ( 704 ) the gallbladder  104  first (shown in  FIGS. 1A-1B ), radially expands ( 706 ) in the gallbladder  104  (shown in  FIGS. 1C-1D ) and pushes ( 708 ) any gallstones  102  in the gallbladder  104  down to or at least towards a distal end of the gallbladder  104  and away from the gallbladder opening (shown in  FIGS. 1D-1E ), thereby clearing a space within the gallbladder for proper and/or full expansion of the filter device. 
     In an embodiment of the invention, the filter device  200  is then introduced ( 710 ) to the gallbladder  104  (now that the area in the gallbladder  104  near the opening has been cleared or substantially cleared of gallstones  102 ) so that the filter device  200  can properly expand ( 712 ) to provide filtering. Introduction of the filter device  200  and expansion in a cleared area is schematically shown in  FIGS. 2A-2C . In some embodiments of the invention, the filter device  200  expands ( 712 ) to its intended size and shape upon arrival at the desired site of implantation. 
     In some embodiments of the invention, the filter device  200  is also provided with blocking capability and functionally operates to both block (to clear out gall stones to make room for filter expansion) and filter. Exemplary devices for performing both functions in the same device are shown and described with respect to  FIGS. 3A-3C  and  FIGS. 4A-4C , below. In some embodiments of the invention, the blocking device  100  also functions as a filter, in addition to and/or alternatively to the filtering device  200 . 
     In some embodiments of the invention, the filter device  200  expands ( 712 ) as a consequence of its own spring-like behavior, for example upon deployment from a catheter  106  which was used to pass the filter device  200  to the cystic duct and/or gallbladder  104 , the device  200  springs into designed shape and size once the catheter  106  is no longer holding the filter device  200  in a contracted state. Optionally, the filter device  200  expands ( 712 ) as a result of its shape memory characteristic. In some embodiments of the invention, an expansion balloon is used to expand the filter device  200 . Due to the special anatomic structure of the cystic duct in the gallbladder region, more than one balloon and/or one balloon inflation may be used, for example, using a flexible balloon for initial inflation and a rigid and/or a semi-rigid balloon for filter device fixation. 
     Optionally, the blocking device  100  is withdrawn after the filter device  200  has been deployed, for example through an opening in the filter device configured for passage of the blocking device  100  therethrough. Optionally, the opening is elastic, sphincter-like, and/or at least partially closes after the blocking device  100  passes through while being withdrawn. 
     Besides the implantation method described above, any other technique leading to the Sphincter of Oddi and/or the gallbladder  104 , such as laparoscopy or open surgery, may be used. 
     In an embodiment of the invention, the filter device  200  and/or the blocking device  100  can be removed or are designed to be bio-absorbed at any time. 
     In some embodiments of the invention, medical imaging is used for guiding the navigation of the biliary tree and/or implantation of the blocking device  100  and/or filter device  200  at the correct implantation site. Optionally, a scope is used to provide imaging. Optionally, x-ray is used to provide imaging. Optionally, ultrasound is used to provide imaging. 
       FIGS. 3A-3C  are side views of two tier filtering devices  300 ,  320 ,  340 , respectively, in accordance with exemplary embodiments of the invention. In an embodiment of the invention, the two tier filtering devices  300 ,  320 ,  340  are provided with a combination filter/blocker portion  302 ,  322 ,  342 , respectively and an anchoring portion  304 ,  324 ,  344 , respectively. 
     In an embodiment of the invention, the filter/blocker portion  302 ,  322 ,  342  is configured to enter the gallbladder  104  prior to the second tier, or anchoring portion  304 ,  324 ,  344 , which when the filter/blocker portion  302 ,  322 ,  342  expands pushes any gallstones away from the opening of the gallbladder  104 , both to prevent gall stones from entering the biliary tree and also to ensure proper deployment/expansion of the anchoring portion  304 ,  324 ,  344 . 
     In an embodiment of the invention, the anchoring portion does not exert radial force on the wall of the gallbladder  104  and/or does not anchor by attaching itself or latching onto a wall of the gallbladder  104 . In some embodiments of the invention, the anchor portion  304 ,  324 ,  344  works in combination with a stopper  306 ,  326 ,  346  which when taken together stretch substantially the length of the gallbladder  104 , preventing the devices  302 ,  320 ,  340  from moving axially in the gallbladder (that is, preventing the device from migrating away from the opening to gallbladder). 
       FIGS. 4A-4C  are top views of the filter/blocking portions  302 ,  322 ,  342  of filtering devices  300 ,  320 ,  340 , in accordance with exemplary embodiments of the invention. In some embodiments of the invention, at least the filter/blocking portion  302 ,  322 ,  342  is configured so that there is spacing between the wires sufficient for blocking gallstones of a specified minimum size, but are also far enough apart to avoid growth of bacterial films, and other bio-film growth, between the wires which could block the natural flow of material from the gallbladder into the biliary tree. 
     In some embodiments of the invention, the filter/blocking portion is configured to block gallstones approximately  5 mm or more in diameter. In some embodiments of the invention, spaces between wires form an opening no greater than 4 mm×4 mm. 
     In some embodiments of the invention, the filter portion and/or blocking portion and/or anchoring portion are mesh, spiral/coiled and/or a perforated sheet. In some embodiments of the invention, the device is shaped to allow for slight movement within the implantation site in order to prevent or delay bio-film growth via device motion. Optionally, the device is moved by movement of the gallbladder and/or the surroundings of the implantation site itself. In an embodiment of the invention, the device moves and/or flexes to cause any accumulation of bio-film to break, crack and/or at the very least create openings through the bio-film such that natural secretions of the gallbladder continue to flow. 
     The device material is selected to be biocompatible and/or bio-absorbable, in an exemplary embodiment of the invention. Optionally, the device is constructed of a polymer material. In some embodiments of the invention, the device is at least partly metal. Optionally, the device is at least a shape memory alloy such as nickel titanium, also known as Nitinol®. In some embodiments of the invention, at least a portion of the device is coated, for example with Teflon® or other similarly inert or highly non-reactive coating. Optionally, at least a portion of the device and/or the coating is adapted to elute a substance, for example a pharmaceutical. Optionally, an anti-bio-film agent, like an antibiotic, is eluted from and/or covers at least a portion of the device. 
     In some embodiments of the invention, the entire device is constructed of a single filament. In an embodiment of the invention, the blocking portion (if separate, such as in the case of the device shown in  FIGS. 1A-1E ) and/or the filter portion and/or anchoring portion are separately formed elements which are connected together. In some embodiments of the invention, at least two of the portions are connected by at least a single filament. Optionally, at least two of the sections are connected by a plurality of filaments. 
     Optionally, the anchoring portion  304 ,  324 ,  344  could have a configuration shown in any of  FIGS. 4A-4C . Optionally, a separate blocking or filter portion could have a configuration shown in any of  FIGS. 4A-4C . 
       FIGS. 5A and 5B  are perspective views of a filtering device  500 , in accordance with an exemplary embodiment of the invention.  FIG. 5B  shows an exemplary filtering device  500  configured with a filter/blocking portion  502  and a stopper  504 .  FIG. 5A  is a perspective view of a cross-sectioned gallbladder  104  with the filtering device  500  implanted within the gallbladder  104 . In an embodiment of the invention, filtering device  500  is deployed after a blocking device  100  has been deployed. Optionally, the blocking device  100  is removed after the filtering device  500  has been placed in the gallbladder  104 . In some embodiments of the invention, the filter/blocking portion  502  is located near an opening  506  to the gallbladder  104  to prevent gallstones  102  of a certain minimum size from leaving the gallbladder  104 . In some embodiments of the invention, the stopper  504  is configured to avoid puncturing a wall of the gallbladder, for example by having a rounded shape. In some embodiments of the invention, the stopper  504  (including the length of filament leading to the stopper) and the filter/blocking portion  502  operate in conjunction (by substantially stretching the length of the gallbladder) to reduce the chance of movement of the filter/blocking portion  502  from migrating away from the opening  506 . 
       FIG. 5C  is a side view of a filtering device delivery system  550  for implanting a filtering device, for example filtering device  500 , in accordance with an exemplary embodiment of the invention. For efficiency, the filtering device delivery system  550  of  FIGS. 5C and 5D  is described in conjunction with the a method of deploying a filtering device in a gallbladder shown in the flowchart  800  of  FIG. 8 . It should be understood, that while filtering device  500  is shown in  FIGS. 5C and 5D , any of the filtering devices or filtering device variations described herein could be used and/or deployed as described herein. In an embodiment of the invention, a conventional delivery system for a biliary stent is used for delivery of a filtering device  500  (or any of the filtering devices described herein). 
     In some embodiments of the invention, the delivery system includes a catheter  552 , within which a guiding rod  554  with a tip  556  mounted on a distal end of the guiding rod  554  is inserted. In some embodiments of the invention, the tip  556  is used for assisting with the navigation ( 802 ) of the catheter  552  within the patient to an implantation site, for example in the gallbladder. Optionally, the tip is configured to assist with the blocking of stones within the gallbladder during filter device  500  deployment, for example with reversibly deployable structures. In an embodiment of the invention, filtering device  500  is wrapped around guiding rod  554 , between the guiding rod  554  and the catheter  552  (so the body of the patient is shielded from the filtering device). In some embodiments of the invention, filtering device  500  is placed substantially on one side of the guiding rod  554  (and temporarily trapped there by the catheter  552 ), such that deployment of the filtering device  500  is from the side when the catheter  552  is retracted instead of longitudinally axially. A substantially side-mounted filtering device  500  is shown in  FIG. 5D , described in more detail below. It should be understood that side-mounting the filtering device  500  enables the retention of the guiding rod  554  in the implantation site while still allowing the device  500  to deploy. As described elsewhere, retention of the guiding rod  554  at least facilitates locating the device  500  within the implantation site or facilitates pushing stones distally in the gallbladder for unimpeded device  500  deployment, in an embodiment of the invention. 
       FIG. 5D  is a side view of the filtering device delivery system  550  with the filtering device  500  partially deployed, in accordance with an exemplary embodiment of the invention. In an embodiment of the invention, the catheter  552  has been withdrawn ( 804 ) partially in a proximal direction, leaving the guiding rod  554 , around which the filtering device  500  is wrapped, proximal to the implantation site. As the catheter  552  is withdrawn further, more and more of the filtering device  500  is deployed into the implantation site and at least partially expands ( 806 ) into shape. For example, the stopper  504  of filtering device  500  has assumed a loop configuration having been freed from the catheter  552 , whereas it was compressed for delivery when it was within the catheter  552  and wrapped around the guiding rod  554 . In some embodiments of the invention, the deployed stopper  504  (or other stoppers  1000 ,  1010 ,  1020  described herein) pushes ( 808 ) gall stones down in the gallbladder towards the distal wall of the gallbladder in order to provide sufficient space within the gallbladder near the gallbladder opening for unimpeded expansion of the filtering portion of the device  500 . In an embodiment of the invention, the filtering device  500  when fully expanded and deployed will resemble the filtering device  500  depicted in  FIG. 5B . In an embodiment of the invention, the guiding rod  554  is also withdrawn ( 810 ) from the implantation site, once the filtering device  500  has been fully deployed, leaving the filtering device  500  by itself within the implantation site, or gallbladder. 
     In some embodiments, pushing ( 808 ) is achieved by holding the catheter  552  in relative place while the filter device  500  is deployed stopper first and/or the guiding rod  554  is advanced distally. In some embodiments of the invention, the blocking portion/pusher are a part of the filter device, such as described herein, and/or are a part of the delivery system (e.g. the catheter or guiding rod). In some embodiments if the invention, the guiding rod  554  is used to assist with locating the filter device within the gallbladder or implantation site, for example where the filter device is wrapped around the guiding rod prior to deployment the guiding rod can located the filter device at a particular depth of insertion, or even direction of insertion, within the gall bladder. In some embodiments of the invention, the guiding rod is used for pushing ( 808 ) gall stones distally in the gallbladder prior to or during deployment of the filter device. 
       FIG. 6  is a top view of a filtering device  600  in situ, in accordance with an exemplary embodiment of the invention. In an embodiment of the invention, the device  600  is blocking/filtering gall stones  602  of a specified minimum size and preventing them from leaving the gallbladder. 
       FIG. 9A  is a side view of a filtering device  900  with leaves  906  of a filtering portion  902  and a split stopper  904 , where the filtering portion  902  and the stopper  904  are connected by a tail  912 , in accordance with an exemplary embodiment of the invention. In an embodiment of the invention, the leaves  906  are formed of the single wire of the device by repeated curves which give a leaf-like, but open, shape. In some embodiments of the invention, there are a plurality of formed leaves, for example anywhere from 2-7 leaves. Optionally, there are more leaves. In an embodiment of the invention, the number of leaves, which optionally overlap at least partially helps to determine the size of particles that are filtered by the filtering portion, wherein as the number of leaves increase, optionally overlapping, impede smaller and smaller stones are filtered. In some embodiments of the invention, the number of leaves helps to determine the amount of pressure exerted by the filter device on the surrounding body tissue, where generally the more leaves there are, the less pressure exerted on the body by any single one. In an embodiment of the invention, the leaves  906  are ovoid, spherical, circular or oblong shaped, as examples. In some embodiments of the invention, the tail  912 , or a portion of it, is welded to at least one of the leaves  906 . In some embodiments of the invention, any loose ends of the wire are attached, optionally by welding, such that there are no loose ends in a finished filtering device. 
     In some embodiments of the invention, the filtering device  900  has two stopper structures  908 ,  910  instead of one, such as shown in  FIG. 5B . In an embodiment of the invention, the two stopper  908 ,  910  stopper configuration increases the contact area (over having just one stopper) between the filtering device  900  and a distal wall of the gallbladder and/or reduce pressure exerted on the stopper, generally, and subsequently the amount of counter-force applied by the device  900  on the gallbladder. In some embodiments of the invention, the filtering portion  902 , the tail  912  and the stopper  904  are disposed entirely within the gallbladder, substantially uncompressed or shaped by the walls of the gallbladder, when implanted. In some embodiments of the invention, at least the two stopper structures  908 ,  910  and the tail  912  are all co-planar. In some embodiments of the invention, having at least two tails enables the filtering device  900  to adapt better to the size and/or shape of the gallbladder relative to a filtering device with only one tail, at least because the plurality of tails are more articulate. In an embodiment of the invention, the split tail/stopper configuration provides a deformation ability, optionally elastic deformation, to the filter device, for example upon the exertion of axial pressure on the device. Optionally, the stopper and/or tail represent 10%-4 0 % of the device&#39;s overall length. 
     In some embodiments of the invention, the tails are of different lengths, for example to bias the filtering device in the gallbladder and/or to adapt the filtering device to a shape of the gallbladder. In some embodiments of the invention, having a plurality of stoppers provides redundancy in case at least one stopper is blocked from reaching the distal wall of the gallbladder by debris (e.g. stones) within the gallbladder. 
       FIG. 9B  is a side view of a filtering device  920  with large overlapping leaves  926  of a filtering portion  922 , in accordance with an exemplary embodiment of the invention. In an embodiment of the invention, the leaves  926  are configured to have a wider minor axis, in relation to other embodiments described herein, for example device  900 . In an embodiment of the invention, the leaves  926  are ovoid or oblong shaped. In an embodiment of the invention, the tail/stopper are a variant of a leaf or petal, for example of generally similar shape to the leaves  926  but elongated. 
     In some embodiments of the invention, a leaf  926  occupies 30° to 120° in radial circumference around the longitudinal axis of the filter device, is between 1 cm and 10 cm in length and/or between 20% and 60% of a nominal gallbladder&#39;s length and/or up to 80% of a nominal gallbladder&#39;s maximal diameter. These ranges are given as guidelines only, and actual filter devices could be larger or smaller in any of the recited dimensions. 
     In an embodiment of the invention, the leaves  926  are configured to overlap in order to provide a filtering structure that will filter small diameter particulates, such as gallstones. It should be understood that as the amount of leaf overlapping is increased, the smaller the stones that will be filtered, in an embodiment of the invention. 
     In an embodiment of the invention, a stopper  928  of the device  920  is curved to minimize trauma to the patient and is connected to the filtering portion  922  by a tail  924 . 
     In some embodiments of the invention, the filtering portion  922 , the tail  924  and the stopper  928  are disposed entirely within the gallbladder, substantially uncompressed or shaped by the walls of the gallbladder, when implanted. 
       FIGS. 10A-10C  are side views of different stopper configurations, in accordance with exemplary embodiments of the invention. It should be understood that the stopper configurations described with respect to  FIGS. 10A-10C  could be used with any of the filter devices described herein. It should also be understood that in some embodiments of the invention, the stopper portion (for example, those described in  FIGS. 10A-10C ) of a filtering device is usable in a similar fashion to the blocking device  100  or portions  302 ,  322 ,  342  described elsewhere herein, that is, to push gallstones to the distal portion of the gallbladder prior to deployment and expansion of the filtering section at least to allow for unimpeded expansion of the filtering section. In some embodiments of the invention, the stopper and/or the tail is configured to deform to provide compliance with various gallbladder sizes and/or geometries. Optionally, the stopper and/or tail designs are also configured to deform in order to maintain or decrease force applied to the gallbladder wall. 
     In some embodiments of the invention, the stoppers deploy in either two dimensions or three dimensions. Optionally, three-dimensional stoppers provide more prevention of filter device movement, more pressure reduction against the gallbladder wall and/or more compliance to gallbladder shape and/or exerted forces during use. 
     In an embodiment of the invention,  FIG. 10A  shows a stopper  1000  with a mushroom-like configuration (biased towards the opening of the gallbladder) intended to increase the surface area of contact between the filtering device and the wall of the gallbladder, thus decreasing the pressure exerted by area of the device on the patient. 
       FIG. 10B  shows a stopper  1010  configured with a spring-like shape which could optionally be resilient, absorbing force to dampen pressure exerted on the wall of the gallbladder in which the filtering device is deployed. 
       FIG. 10C  shows a stopper  1020  which is configured with concentric circles. In an embodiment of the invention, the concentric circles extend in three dimensions, for example extending perpendicular to the tail, increasing the contact area between the stopper and the gallbladder wall. 
       FIGS. 11A-11C  are side views of a schematic deployment sequence of a filtering device  1100  using a delivery system  1150 , in accordance with exemplary embodiments of the invention. In some aspects, at least some aspects of the sequence shown in  FIGS. 11A-11C  is similar to that described with respect to the delivery system  550  of  FIGS. 5C-5D . In an aspect, the delivery system  1150  includes the use of a shaped tip  1152 , optionally similar to tip  556  described with respect to  FIGS. 5C and 5D , and follows a deployment methodology such as described with respect to  FIG. 7  and  FIG. 8 , which assists with navigating within the body to the implantation site in the gallbladder  104 . In an aspect, the delivery system  1150  also includes an external catheter  1154  and/or a guide wire  1156 . Optionally, the filtering device  1100  is side-loaded into the external catheter  1154 , on the side of an internal catheter on which the tip  1152  is disposed. Optionally, the filtering device  1100  is wrapped around the internal catheter. In some aspects, the tip  1152  is threaded through apertures  1104  in at least a blocking section  1102  (shown in  FIGS. 11B and 11C ) of the filtering device  1100  before loading into the external catheter  1154 . 
     In  FIG. 11A , the guidewire  1156  is inserted into the patient and navigated to the gallbladder  104  into which the filtering device  1100  is to be implanted, in an aspect. The external catheter  1154 , containing the filtering device  1100  (and/or any other component which needs to be delivered to the implantation site) is placed over the guide wire  1154  and advanced in a distal direction into and through the patient to the gallbladder  104 , in some embodiments. In some embodiments, the guidewire  1156  is used in conjunction with medical imaging to verify or determine proper/desired location of filtering device  1100  implantation. In some embodiments, the use of the guidewire  1156  enhances patient safety by reducing the likelihood of a part of the delivery system piercing and/or physically damaging the gallbladder  104  wall. In some embodiments, the use of the guidewire  1156  creates an ascertainable path of travel for the filtering device  1100  and/or the delivery system, enhancing various facets of implantation such as pushing gall stones  102  away from the gallbladder  104  opening along a known and/or desirable path (optionally coordinated with known location of gall stones  102 ). 
       FIG. 11B  shows the beginning of filtering device  1100  deployment out of the external catheter  1154 , wherein the blocking section  1102  has been advanced out of the external catheter  1154 , or the external catheter  1154  has been retracted, or both, and the blocking section  1102  has at least partially expanded to engage and push gall stones  102  away from the gall bladder opening.  FIG. 11C  shows the tip  1152  and the blocking section  1102  advanced distally and further into the gallbladder  104 , pushing the gall stones  102  farther away from the gall bladder opening. In some embodiments, the external catheter  1154  would be retracted and/or the filtering device  1100  would be pushed out of the external catheter  1154  to fully deploy within the gallbladder  104  (i.e. the blocking section  1102 , when the device  1100  is fully deployed, is disposed near the distal wall of the gallbladder  104  while the filtering section, shown in  FIGS. 11B and 11C  still contracted in the external catheter  1154 , expands and is disposed near the gallbladder opening). Subsequently, the tip  1152  and/or the guidewire  1156  would be withdrawn, optionally through apertures  1104  in the filtering device  1100 . 
       FIG. 12  is a side view of a filtering device  1200  with a generally egg-shaped or ovoid body, in accordance with exemplary embodiments of the invention. In an aspect, it is configured such that the filtering device  1200  is formed and/or configured to and/or assumes a shape that is approximately the same as the gallbladder  104  in which it is implanted and, typically, the gallbladder is  104  egg-shaped. As with other filtering devices described herein, filtering device  1200  is adapted to expand (e.g. shape memory, inflation balloon, elastic/springy characteristic) when expelled from a deployment system, such as an external catheter, as described elsewhere herein. The expandability of the filtering device  1200  enables the filtering device  1200  to expand to approximately the size and/or shape of the gallbladder  104 , trapping any gall stones  102  within or against the gallbladder  104  wall. In some embodiments, there is more structure of the device  1200 , more densely arranged near the gallbladder  104  opening such that a filtering function is performed by the structure at least at that point. In some aspects, it is also conceived that the egg or ovoid shape, which closely mimics the natural shape of the gallbladder  104 , reduces or eliminates (i.e. the filtering device  1200  free-floats, or nearly so, in the gallbladder  104  while also occupying nearly all of the empty space within the gallbladder  104 ) the chances of pressure or localized pressure being exerted on the wall of the gallbladder  104 , enhancing patient comfort and safety. 
     In some aspects, the filtering device  1200  is a continuous coiled wire or filament which is formed into an egg-like or ovoid shape, with at least one coiled loop to form a cage-like structure with a space therein for trapping gall stones  102 . In some aspects, such as what is shown in  FIG. 12 , two ends of a linear wire are welded  1202  together to form the device&#39;s shape. In other aspects, such as shown and described in more detail below with respect to  FIGS. 15A-15B , joining rings are used create the device shape from a plurality of wires or filaments. It should be understood that these are by way of example only, and that conceivably any mechanism and/or technique which would result in an ovoid or egg-like shape could be used. 
     As with other filtering devices described herein, filtering device  1200  (and any of the filtering devices or “wires” described below) could be made from a shape memory alloy like Nitinol®. They could also be made from metals, polymers, composites or any combination thereof. In some embodiments, wire means a wire or filament as conventionally understood, however, “wire” in some embodiments could mean material  2100 ,  2110  cut (e.g. laser) from a sheet  2102  or a tube  2112 , such as shown in  FIGS. 21A-21B , and optionally welded into shape. In some embodiments, there are layers of materials, for example a coating on the wires. The thickness of the material is typically 0.05 mm-0.35 mm, but could be thinner and/or thicker (that is, the device isn&#39;t all the same thickness of material) depending on the material being used and/or the shape and/or the configuration of the filtering device. 
       FIG. 19  is a plan view of at least a part  1900  of a filtering device, in accordance with an exemplary embodiment of the invention, which is what at least a part of a filtering device might look like in a semi-manufactured state, for example, having just been cut from a sheet like in  FIG. 21A . In an exemplary embodiment, the part  1900  includes a filtering and/or blocking portion  1902  and an anchoring/neck/tail (depending on how the part  1900  is used) portion  1904 . 
       FIG. 20A-20C  are side views which provide examples of filtering devices  2000 ,  2010 ,  2020  which could be made from one or more parts  1900 , in accordance with some exemplary embodiments of the invention.  FIG. 20A  shows a filtering device  2000  which has two parts  1900  welded  2002  together end to end at the neck portions  1904   i ,  1904   ii  such that the filtering portions  1902   i ,  1902   ii  are disposed on opposite ends of the overall device  2000 .  FIG. 20B  shows a filtering device  2010  where the neck portions  1904  are bent into a circle at their ends and optionally welded  2002  themselves (forming a “tail” similar to that shown in  FIG. 9A ).  FIG. 20C  shows a filtering device  2020  constructed of part  1900  where the ends of the neck  1904  are welded to each other to form a closed loop (forming a “tail” similar to that shown in  FIG. 9B ). 
       FIG. 13  is a side view of a double layered egg-shaped filtering device  1300 , in accordance with exemplary embodiments of the invention. In some aspects, the filtering device  1300  is similar to the filtering device  1200 , but with an internal blocking portion  1302  disposed in an interior space of the filtering device  1300  near the gallbladder  104  opening. The blocking portion  1302  operates to filter gall stones  102  alternatively and/or additionally to the outer portion (which is structurally similar to filtering device  1200 ) of the filtering device  1300 . In some aspects, the blocking portion  1302  and the outer portion are a continuous wire or filament. In some aspects, the blocking portion  1302  is a separate structure attached to the outer portion. Optionally, the blocking portion  1302  is also egg-shaped. In some embodiments, the blocking portion  1302  and the outer portion are sequential in space rather than axially overlapping. In some embodiments, at least a portion of the blocking portion  1302  is contained within the outer portion but not axially aligned. 
       FIG. 14  is a side view of an asymmetrically-meshed, egg-shaped filtering device  1400 , in accordance with exemplary embodiments of the invention. In some embodiments, an outer portion of the filtering device  1400  is similar to filtering device  1200 , however, there is additionally provided a mesh structure  1402  on the side  1404  of the filtering device  1400  which abuts the gallbladder  104  opening when the device  1400  is deployed. In some aspects, gall stones  102  remain entrapped within the outer portion of the filtering device  1400  and are preventing additionally and/or alternatively by the mesh structure  1402 . In some embodiments, the “mesh” structure  1402  comprises a plurality of leaf or petal shapes, optionally overlapping at least partially, such as other leaf shapes described herein (particularly with respect to  FIGS. 9A-9B ). In some embodiments, at least a portion of the mesh structure  1402  is located outside the outer ovoid or egg-shaped portion. 
       FIGS. 15A-15B  are side views of ringed, egg-shaped filtering devices  1500 ,  1550 , in accordance with exemplary embodiments of the invention.  FIG. 15A  shows a filtering device  1500  comprised of a plurality of wires, the ends of which are joined together by a joining ring  1506 . It should be understood that while an inner wire  1502  and an outer wire  1504  are shown, any number of wires could be used to construct filtering device  1500 . Further, it should be understood that this filtering device  1500  could optionally exhibit an egg or ovoid shape in three dimensions when it expands after deployment, rather than in the two dimensions shown. In an aspect, the joining ring  1506  is positioned near the gallbladder  104  proximal end  1508  of the filtering device  1500 , when the device  1500  is implanted. 
     In some embodiments, an indentation (shown as indentations  1558  in  FIG. 15B ) is created by the wires  1502 ,  1504  being curved around and linked together by the ring  1506 , which in  FIG. 15A  lies within the interior of the filtering devices  1500 . In some embodiments, the indentations and/or the rings act to resist shape change away from the expanded/deployed configuration and back to the compressed configuration exhibited when in the external catheter. For example, the proximal end  1508 , if it becomes lodged within the gallbladder  104  opening could feel pressure from the walls of the body lumen to compress, possibly to the point of losing its ovoid or egg-like shape. It is conceived that the indentation will counter this urge to compress. This indentation, and also possibly the indentations shown in  FIG. 15B , are optionally used to collect gall stones  102  which are loose outside the perimeter formed by the filtering device  1500 , in some embodiments. In some embodiments, the space created by the indentation enables the filtering device  1500  to distort/flex/adapt its shape upon deployment in the gallbladder  104 , for example if there are multiple gall stones  102  which obstruct full deployment of the filtering device  1500  or if the gall bladder  104  itself is smaller than the fully expanded device. In some embodiments, the indentation is not at an end, but located elsewhere around the exterior of the filtering device  1500 . It should be understood that any of these above described embodiments could also be applied to any of the other filtering devices described herein, and of particular note, filtering device  1550 . 
       FIG. 15B  shows a filtering device  1550  which includes a plurality of joining rings  1556 ,  1560  which are used together to impart a slightly different shape to filtering device  1550  than filtering device  1550 . Overall, the filtering device  1550  still exhibits an ovoid or egg shape, but is symmetrically shaped with at least two opposing indentations  1558  where the joining rings  1556 ,  1560  are located). As with the filtering device  1500 , filtering device  1556  exhibits a three-dimensional egg or ovoid shape, when expanded after deployment, in some aspects. In the filtering device  1550  of  FIG. 15B , the inner layer  1552  is formed from two wires, with each end joined at a joining ring  1556 ,  1560 , while the outer layer  1554  is constructed similarly. 
       FIG. 16  is a side view of a two layered filtering device  1600 , in accordance with exemplary embodiments of the invention. In some aspects, filtering device  1600  is provided with a gall stone pushing layer  1604  and a filtering layer  1602 . In some aspects, the pushing layer  1604  is deployed/expanded before the filtering layer  1602  to reduce the likelihood that a gall stone  102  passes into the biliary system before the filtering device  1600  can be properly/fully deployed, such as described with respect to other filtering devices described herein (e.g.  FIGS. 1A-4C ). In some embodiments, the pushing layer  1604  is used to move gall stones  102  away from the filtering device  1600  so that they do not impeded device  1600  expansion or block or contort expansion of the device. In some aspects, the pushing layer  1604  and the filtering layer  1602  work together to provide filtering, to prevent gall stones  102  from migrating into the biliary tree. Optionally, the pushing layer  1604  is a finer filter than the filtering layer  1602 . In some embodiments, the pushing layer  1604  is similar to blocking layers or portions described elsewhere herein. 
     In some aspects, the filtering device is provided with an anchoring portion  1606  or stopper, which spaces the pushing layer  1604  and the filtering layer  1602  away from a distal wall of the gallbladder  104 , and occupying the length of the gallbladder  104  such that the blocking layer  1604  and filtering layer  1602  remain close to, or abut, the gall bladder opening. A neck  1608  of the filtering device  1600  connects the anchoring portion  1606  to the blocking layer  1604 . In some embodiments of the invention, at least the neck  1608  is flexible to conform to a particular gallbladder&#39;s  104  geometry and/or to changes in size and/or shape of the gallbladder  104  due to being in a living being, and/or to debris or other materials within the gallbladder  104 . In some embodiments of the invention, the filtering device  1600 , and/or any of the other filtering devices described herein, do not apply any expansive force on the wall of the gallbladder  104 . In some embodiments, at least the anchoring portion  1606  and the neck  1608  are a single bent wire or filament. In some embodiments, the anchoring portion  1606  is comprised of multiple wires or other surface area increasing structures (such as at least one pad), to reduce localized pressure exerted by the filtering device  1600  on the gallbladder  104  wall. 
       FIGS. 17A-17B  are side views of a filtering device release configuration and a filtering device retained configuration of a filtering device deployment system, respectively, as described in more detail below. 
       FIGS. 17C-17D  are side views of a schematic deployment sequence of a filtering device using a filtering device deployment system, in accordance with exemplary embodiments of the invention. 
     For efficiency,  FIGS. 17A-17D  will be described in conjunction with  FIG. 18 , a flowchart of a method  1800  of deploying a filtering device using a filtering device deployment system including at least a release wire  1706 , in accordance with an exemplary embodiment of the invention.  FIGS. 17C-17D  show the progression of the deployment of a filtering device (e.g., any of the filtering devices described herein) wherein the release wire  1706  is used to releasably retain a filtering device  1700  within an external catheter  1702  during navigation and until the filtering device  1700  is to be deployed. In some aspects, the release wire  1706  is attached on a central cylinder  1708  (e.g. guiding rod) near a distal end of the central cylinder, proximal to a distal end of the external catheter  1702 . In some embodiments, the release wire  1706  is attached to a ring  1704  located near and around the distal end of the central cylinder  1708 . In some aspects, the release wire  1706  is biased to be straight, such as shown in  FIG. 17A , with a straight and un-tensed release wire  1706  but prior to deployment of the filtering device  1700  is hooked (such as shown in  FIG. 17B-17C ). 
     In use, the filtering device  1700  is retained ( 1802 ) by the release wire  1706  due to its configuration into a hooked shape (shown with the filtering device  1700  in  FIG. 17C  and without the device, for clarity, in  FIG. 17B ). Upon retraction ( 1804 ) of the external catheter  1702  and/or pushing ( 1806 ) of the central cylinder  1708  forward, the hooked release wire  1706  eventually clears the restraint put on it by the external catheter  1702 , thereby causing the release wire  1706  to assume its naturally straight configuration and subsequently releasing ( 1808 ) the filtering device  1700 , shown in  FIG. 17D . In some aspects, the hooked release wire  1706  is hooked through a filtering layer (or most proximal layer) such that a blocking layer (or most distal layer) is not retained by the release wire, and can expand/deploy to start pushing gall stones  102  away from the gallbladder  104  opening. In some aspects, the external catheter  1702  and/or the central cylinder  1708  and/or any guide wire or other part of the delivery system is retracted ( 1810 ) from the patient&#39;s body. In some aspects, it is conceived that holding the release ( 1808 ) of the filtering device  1700  allows the attending medical professional to be satisfied, using for example medical imaging, with the location of the device  1700  implantation before effectuating separation of the filtering device  1700  into the gallbladder. 
     The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”. 
     The term “consisting of” means “including and limited to”. 
     The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. 
     As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof. 
     Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. Further, described ranges are intended to include numbers outside any range described within statistical error and/or inherent measurement equipment limitations. 
     Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. 
     As used herein the term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts. 
     As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. 
     All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.