Patent Publication Number: US-2010121371-A1

Title: Non-endoscopic insertion and removal of a device

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application 60/927,101 to Brooks, entitled, “Non-endoscopic insertion and removal of a device,” filed Apr. 30, 2007, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to apparatus and methods for inserting medical apparatus. Specifically, the present invention relates to apparatus and methods for non-endoscopic insertion and removal of a device in the gastrointestinal tract. 
     BACKGROUND OF THE INVENTION 
     Intragastric balloons can be used to treat bariatric patients with Class 2 or Class 3 obesity (BMI&gt;30 kg/m2) and are designed to provide short-term therapy for moderately obese individuals who need to lose weight in preparation for surgery, or as part of a dietary and behavioral modification program. Generally, placement and removal of the intragastric balloon requires the use of endoscopy. In some cases, a hospital stay of one to two days is required to fit the balloon to the specific patient. 
     PCT Publication WO 06/070361 to Brooks, which is incorporated herein by reference, describes apparatus for use in a gastrointestinal tract of a subject. The apparatus includes a straightening rod, and a flexible tubular anchor having a distal end and an open proximal end, and sized to fit in the gastrointestinal tract. The anchor is described as comprising a material that has an elastic memory which biases the anchor toward assuming a pre-selected bent configuration. The anchor is described as being shaped so as to define a central core extending from the open proximal end toward the distal end. The anchor is configured to be straightened from the pre-selected bent configuration by insertion of the straightening rod in the central core. The apparatus further includes a device coupled to the anchor, selected from the list consisting of: a therapeutic device, and a transmitting device. Other embodiments are also described. 
     PCT Publication WO 07/110866 to Brooks, which is incorporated herein by reference, describes apparatus for use in a stomach of a subject. The apparatus includes a balloon, adapted for placement in the stomach, and an anchor, coupled to the balloon. The anchor is adapted to prevent the balloon from passing into a duodenum of the subject. The apparatus further includes an inflation tube, coupled to the balloon to permit inflation of the balloon, and is adapted to stretch from the stomach to a mouth of the subject to facilitate inflation of the balloon. Other embodiments are also described. 
     U.S. Pat. No. 6,569,173 to Blatter et al., which is incorporated herein by reference, describes compression plates and vascular anvils for anastomosis of structures including end-to-end and end-to-side anastomosis. Vascular anvils are described to cooperate in the opening of the anastomosis fenestra, engagement by a compression plate and subsequent eversion of the anastomosis fenestra contour, and also in establishing the contact engagement of the anastomosed structures. Compression plates are described as holding anastomosed structures while permitting their dilation and keeping the anastomosis leak-proof. One of the compression plates is described as assisting in the eversion of the anastomosis fenestra contour. These compression plates and vascular anvils are described as being used with or without catheterization in minimally invasive interventions. A non-endoscopic extravascular device (hereinafter referred to as “peripheral device”) is described as being used when there is no need to use a visual aid, such as an endoscope, in a peripheral procedure. An endoscopic or peripheral device is described as carrying a compression plate device and the graft vessel, and engages the extravascular portion of the wire. 
     US Patent Application Publication 2002-0055757 to Torre et al., which is incorporated herein by reference, describes a space occupying device for deployment within a patient&#39;s stomach and methods of deploying and removing the device. The device is described as including an expandable member and fasteners, such as sutures, that extend at least partially through the patient&#39;s stomach wall, and that anchor the device with the patient&#39;s stomach. The device is described as being deployed and/or removed through transesophageal approaches and/or through a combination of transesophageal and transabdominal approaches. 
     PCT Publication WO 05/009288 and US Patent Application Publication 2005/0033331 to Burnett et al., which are incorporated herein by reference, describe methods, devices and systems to facilitate intermittent and/or partial obstruction of a pyloric valve. Devices are described as including a support portion for preventing the device from passing through the pyloric valve and a tissue engagement portion for contacting tissue adjacent the pyloric valve to obstruct the valve. Some embodiments are also described as including a positioning member extending from the tissue engagement portion for helping position the device for obstructing the valve. A retaining member is described as being optionally included on the distal end of the positioning member for further maintaining a position of the device in the stomach. Some embodiments are deliverable into the stomach through the esophagus, either by swallowing or through a delivery tube or catheter. Some embodiments are fully reversible. Some embodiments self-expand within the stomach, while others are inflated or otherwise expanded. 
     PCT Publication WO 05/094257 to Birk, which is incorporated herein by reference, describes a gastric balloon and method of adding and removing fluid therefrom. The gastric balloon includes a shell, a receiver, and a retractable tubing housed in the receiver and extendable from the stomach of a patient to the mouth of the patient. The shell is inflated and deflated from outside the body of the patient. The method of adding or removing fluid from the implanted gastric balloon includes steps of inserting a gastroscopic tool into the stomach of a patient and grasping an end of a retractable tubing housed in a receiver of the gastric balloon. Further steps of the method include withdrawing at least a portion of the retractable tubing from the stomach and out of a patient&#39;s mouth and adding or removing fluid from the gastric balloon via the retractable tubing withdrawn from the patient. 
     The following patents and patent applications, which are incorporated herein by reference, may be of interest: 
     British Patent Application Publication GB 2139902 to Celestin et al. 
     Canadian Patent Application Publication 2483335 to Byrum et al. 
     Canadian Patent Application Publication CA 1233387 to Garren et al. 
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     The following articles, which are incorporated herein by reference, may be of interest: 
     Borowski A et al., “Minimally invasive, nonendoscopic saphenectomy for coronary bypass surgery,” J Card Surg 16(6):484-6 (2001) 
     Kadakia S C et al., “Esophageal dilation with polyvinyl bougies using a marked guidewire without the aid of fluoroscopy,” Am J Gastro 88:1381-86 (1993) 
     Fleischer D E et al., “A marked guidewire facilitates esophageal dilation,” Am J Gastro 84:359-61 (1989) 
     Dumon J R et al., “A new method of esophageal dilation using Savary-Gilliard bougies,” Gastro Endosc 31:379-82 (1985) 
     Werth et al., “A safe and quick method for endoscopic retrieval of multiple gastric foreign bodies using a protective sheath,” Surg Gynecol Obstet 171(5):419-20 (1990) 
     SUMMARY OF THE INVENTION  
     In some embodiments of the present invention, a method and apparatus are provided for non-endoscopic insertion and removal of intrabody apparatus. In some embodiments of the present invention, the intrabody apparatus is configured to be implanted within the body of the subject. Additionally, a non-endoscopic method of inflation tube retrieval is provided. 
     Typically, the intrabody apparatus comprises any device configured for insertion into a body of a subject. In some embodiments, the intrabody apparatus is designated for insertion into a stomach of the subject and comprises a non-inflated gastric balloon coupled to a core catheter. In such an embodiment, a pushing tube is configured to guide the apparatus into the body of the subject when the subject is sedated. An inflation tube is typically disposed within a lumen of the pushing tube during insertion of the apparatus into the stomach of the subject. Once the apparatus is inserted into the stomach, the inflation tube is configured to facilitate non-endoscopic inflation and deflation of the gastric balloon from a site outside the body of the subject. 
     Typically, a proximal end of the inflation tube is reversibly coupled to a distal end of an extension tube. A proximal end of the extension tube, or a string coupled to the extension tube, is typically tethered to a prosthesis comprising a mouth appliance. The extension tube is configured to remain disposed at least in part within the esophagus of the subject, coupled to the mouth appliance, to allow for multiple outpatient inflations of the gastric balloon while the subject is awake. Subsequently, e.g., once the gastric balloon is at a desired level of inflation, the extension tube is extracted by removing the mouth appliance tethered thereto. The inflation tube, still attached at its distal end to the gastric balloon, is pulled slightly out of the subject&#39;s mouth so that it can be capped and passively retracted into the stomach of the subject. In the event that future inflations of the gastric balloon are indicated, the inflation tube is extracted from within the stomach using endoscopy, non-endoscopic methods as described herein, or other methods. 
     In some embodiments, the inflation tube coupled to the gastric balloon is extracted from within the stomach using non-endoscopic methods, should a need for further inflation of the gastric balloon arise. The inflation tube is non-endoscopically accessed from within the stomach when a gastric tube comprising hook-and-loop fasteners (e.g., a nasogastric or orogastric tube comprising Velcro strips) at its distal tip successfully hooks and fastens to hook-and-loop fasteners coupled to the inflation tube. Alternatively, the inflation tube comprises a biocompatible and durable net or mesh that extends up to 360 degrees circumferentially around or in a vicinity of its proximal end. (In this context, in the specification and in the claims, “proximal” means closer to the mouth, and “distal” means further from the mouth.) The net or mesh of the inflation tube is non-endoscopically accessed by a hooking mechanism which expands from a retracted state within the lumen of the nasogastric tube. 
     In an embodiment, the core catheter coupled to the gastric balloon comprises silicone at least at its proximal end. During initial insertion of the gastric balloon, the proximal end of the core catheter is ensnared by distal pieces (e.g., wires or control rods) of the pushing tube, creating a temporary coupling which allows the pushing tube to push the device down the esophagus. The pushing tube is later disengaged from the core catheter by a releasing mechanism controlled at the proximal end of the pushing tube. 
     For some applications, the silicone at the proximal end of the core catheter comprises finger-like projections which project distally from the proximal end of the core catheter. These finger-like projections enable ensnaring of the core catheter by an extraction device (e.g., a polypectomy snare or any other tube configured to remove the core catheter from within the stomach). 
     During insertion, non-endoscopic identification that the intrabody apparatus is within the stomach of the subject is accomplished by receiving feedback via first and second openings disposed on a lateral portion of the distal end of the pushing tube. Air is forcefully injected through the first lateral opening of the pushing tube, and is passed into the gastrointestinal lumen, allowing identification of the presence (or absence) of the device within the stomach, by auscultation. 
     Injecting a fluid through the second opening inflates a verification balloon (e.g., a Foley catheter balloon, a Blakemore tube balloon, a Fogarty catheter balloon, or an internal bumper of a percutaneous endoscopic gastrostomy (PEG) tube) encircling or otherwise coupled to the distal end of the pushing tube. Identifying the location of the gastric balloon within the stomach is accomplished by pulling back on the pushing tube and sensing a resistance of the verification balloon against the gastroesophageal junction. For these purposes, 150-200 cc of fluid is typically used to inflate the verification balloon. The gastric balloon is then inflated and the verification balloon is deflated. 
     Following deflation of the verification balloon, the pushing tube is disengaged from the proximal end of the core catheter. The extension tube and inflation tube are left within the esophagus of the subject as the pushing tube is extracted from the gastrointestinal tract of the subject. The extension tube is then coupled to the mouth appliance as described hereinabove, allowing for multiple inflations of the gastric balloon during the time that the extension tube is disposed within the subject. 
     In some embodiments, the extension tube is detached from the inflation tube. The inflation tube is later accessed endoscopically or non-endoscopically from within the stomach of the subject, if desired. A portion of the inflation tube is withdrawn from the subject&#39;s mouth, allowing a fluid-injection valve of the inflation tube to be opened and closed outside the subject&#39;s body, while leaving a portion of the inflation tube within the esophagus of the subject. Accessing the inflation tube comprises pulling the inflation tube from within the stomach of the subject and stretching the tube in order to expose its valve. As such, the inflation tube typically comprises silicone or another stretchable elastomer, or another biocompatible material capable of stretching to at least about 2.5-10 times its original length (e.g., 6 times its original length). 
     In some embodiments of the present invention, a short-acting sedative (e.g., propofol) and/or reversible drug (e.g., a benzodiazepine or a narcotic), is used to sedate the subject for the period of time that the intrabody apparatus is being inserted using the apparatus as described hereinabove. 
     In some embodiments of the present invention, a method for endoscopic insertion of the intrabody apparatus is provided. The apparatus, comprising a gastric balloon coupled to an inflation tube, is endoscopically guided into the gastric lumen of a subject when the subject is sedated by the short-acting sedative and/or reversible narcotic described hereinabove. 
     In some embodiments in which sedatives and/or reversible drugs are used, once the intrabody apparatus has successfully been inserted into the gastric lumen of the subject, the subject is revived by an antidote or due to the transient effects of the short-acting sedative. The gastric balloon is then inflated via the inflation tube while the subject is conscious. A desired level of inflation of the gastric balloon is achieved based on feedback from the conscious subject. 
     In some embodiments of the present invention, a portion of the inserted apparatus, such as the inflation tube or the core catheter, comprises appendages at its proximal tip which project into the gastric fundus. In some embodiments, the appendages are disposed at any suitable location along the inflation tube or the core catheter. Typically, the appendages mechanically stimulate satiety sensors in the fundus. The stimulation induces increased satiety of the subject in combination with the inserted gastric balloon. Alternatively, the stimulation induces increased satiety independently of, or in the absence of, the gastric balloon. In some embodiments, a first portion of the appendages project toward the fundus, while a second portion of the appendages project toward the antrum of the stomach. In such an embodiment, the first and second portions of the appendages are typically disposed upon the inflation tube or the core catheter at respective proximal and distal ends thereof. In embodiments not including a gastric balloon, the appendages may be disposed at any suitable site on the inflation tube or core catheter. 
     In some embodiments, the core catheter comprises or is coupled to at least one support element. In some embodiments, the support element comprises a pair of limbs at the proximal tip of the core catheter and/or a pair of limbs at the distal end of the core catheter. The proximal and distal limbs of the core catheter function as anchors, restricting passage of the device through the pyloric sphincter of the subject. The proximal limbs are configured to restrict the device from passing through the pyloric sphincter if the device is inverted within the stomach. 
     For some applications, the support element is coupled to a skirt which functions as an anchor once allowed to expand within the stomach of the subject. During the insertion procedure, the support element is secured in a closed configuration to allow for smooth passage of the catheter through the gastrointestinal tract. Upon entering the stomach, the support element assumes an open configuration. This open configuration restricts passage of the gastric balloon through a pyloric sphincter of the subject, and the skirt limits the extent to which the support element can open. 
     For some applications in which the support element comprises the proximal and/or the distal limbs, the limbs are configured to be retracted within and extended from the core catheter during insertion and deployment, respectively. For some applications, the proximal and distal ends of the core catheter comprise silicone which is configured to bifurcate, creating “Y” shaped limbs. 
     There is therefore provided, in accordance with an embodiment of the present invention, a method, including: 
     inserting a gastric balloon coupled to an inflation tube into a stomach of a subject without using an endoscope; 
     non-endoscopically identifying a presence of the gastric balloon within the stomach of the subject; and 
     inflating the gastric balloon in response to the identifying. 
     In an embodiment, identifying the presence of the gastric balloon includes injecting air into the stomach and identifying the presence of the gastric balloon by auscultation. 
     In an embodiment, identifying the presence of the gastric balloon includes injecting air into the stomach and identifying by auscultation a presence of a distal end of a balloon pushing tube distal to a gastroesophageal junction of the subject. 
     In an embodiment, inflating the gastric balloon includes passively allowing an inflation tube to retract into the stomach of the subject following the inflating. 
     In an embodiment, the method includes endoscopically accessing an inflation tube coupled to the gastric balloon subsequently to the inflating of the gastric balloon. 
     In an embodiment, the gastric balloon is coupled to a verification balloon, and identifying the presence of the gastric balloon includes: 
     inflating the verification balloon; 
     subsequent to the inflating, sensing resistance of the verification balloon against a gastroesophageal junction of the subject; and 
     identifying that the verification balloon is in the stomach of the subject in response to the sensed resistance. 
     In an embodiment, the method includes pushing the inflated verification balloon in a distal direction, and identifying that the verification balloon is in the stomach includes identifying an ease of the pushing. 
     In an embodiment, the method includes non-endoscopically accessing an inflation tube coupled to the gastric balloon subsequent to the inflating of the gastric balloon. 
     In an embodiment, non-endoscopically accessing includes: 
     inserting, into the stomach of the subject, a nasogastric tube including hook-and-loop fasteners; and 
     hooking the hook-and-loop fasteners to hook-and-loop fasteners coupled to the inflation tube. 
     In an embodiment, non-endoscopically accessing includes: 
     inserting, into the stomach of the subject, a nasogastric tube including a hook at its distal end; and 
     hooking the nasogastric tube to webbing at a proximal end of the inflation tube. 
     In an embodiment, the inflation tube is coupled to an intrabody device, and non-endoscopically accessing includes: 
     inserting, into the stomach of the subject, an ensnaring device; and 
     ensnaring a proximal end of the intrabody device by looping the ensnaring device around a distal end of at least one projection coupled at at least a proximal end thereof to the intrabody device. 
     In an embodiment, inserting the gastric balloon includes tethering to a mouth of the subject an extension tube coupled to an inflation tube, the inflation tube being coupled to the gastric balloon. 
     In an embodiment, tethering the extension tube includes maintaining the inflation tube within an esophagus of the subject. 
     In an embodiment, the method includes accessing the inflation tube from outside a body of the subject and inflating the gastric balloon while the extension tube is disposed within the body of the subject. 
     In an embodiment, inflating the gastric balloon includes periodically inflating the balloon over a duration selected from the group consisting of: at least one minute, at least one hour, at least one day, at least  48  hours, and at least one week. 
     In an embodiment, inflating the gastric balloon includes periodically inflating the balloon over a duration of at least one week. 
     There is further provided, in accordance with an embodiment of the present invention, a method, including: 
     administering a short-acting sedative to a subject; 
     guiding a gastric balloon coupled to an inflation tube into a stomach of the subject; 
     reviving the subject in response to an indication that the gastric balloon is within the stomach; and 
     inflating the gastric balloon in response to conscious feedback from the subject. 
     In an embodiment, reviving includes discontinuing the administering of the sedative. 
     In an embodiment, guiding the gastric balloon includes endoscopically guiding the gastric balloon. 
     In an embodiment, guiding the gastric balloon includes non-endoscopically guiding the gastric balloon. 
     There is still further provided, in accordance with an embodiment of the present invention, apparatus, including: 
     a gastric balloon; 
     an inflation tube coupled at a distal end thereof to the gastric balloon; 
     an extension tube coupled to a proximal end of the inflation tube and configured to facilitate inflation of the balloon while a proximal end of the extension tube is outside a body of a subject or in a mouth of the subject; and 
     a mouth appliance coupled to the extension tube, configured to maintain at least a portion of the extension tube and at least a portion of the inflation tube in an esophagus of the subject. 
     In an embodiment, the mouth appliance is configured to facilitate removal of the extension tube once the gastric balloon has reached a desired level of inflation. 
     In an embodiment, the extension tube is configured to be disengaged from the inflation tube once the gastric balloon has reached a desired level of inflation. 
     In an embodiment, the apparatus includes one or more appendages coupled to the gastric balloon, and the one or more appendages are configured to stimulate satiety sensors of a fundus of a stomach of the subject. 
     In an embodiment, the apparatus includes an extraction device, the inflation tube includes an accessing device at a proximal end thereof, and the extraction device is configured to engage the accessing device. 
     In an embodiment, the accessing device is configured to be non-endoscopically accessed from outside the body of the subject. 
     In an embodiment, the accessing device is coupled to at least one hook-and-loop fastener, and the extraction device includes a gastric tube coupled to at least one hook-and loop fastener. 
     In an embodiment, the at least one hook-and-loop fastener coupled to the gastric tube is configured to access the at least one hook-and-loop fastener coupled to the inflation tube. 
     In an embodiment, the accessing device includes a net, and the extraction device includes a gastric tube and at least one hook coupled to the gastric tube. 
     In an embodiment, the at least one hook is configured to access the net coupled to the inflation tube. 
     In an embodiment, the apparatus includes a core catheter, and the gastric balloon is coupled to a site along the core catheter. 
     In an embodiment, the core catheter includes one or more appendages. 
     In an embodiment, the one or more appendages are configured to stimulate satiety sensors of a fundus of a stomach of the subject. 
     In an embodiment, the one or more appendages are configured facilitate a sensation of satiety by occupying space within a stomach of the subject. 
     In an embodiment, the one or more appendages are configured to stimulate a gastric wall of the subject. 
     In an embodiment, the apparatus includes: 
     an appendage retraction tube configured to be disposed within a lumen of the core catheter and to be coupled to the one or more appendages, 
     the core catheter includes:
         a ring-shaped element; and   at least two support columns configured to support the ring-shaped element at the proximal end of the core catheter, and to define a space between the proximal end of the core catheter and the ring-shaped element.       

     In an embodiment, the one or more appendages are configured to project through the defined space. 
     In an embodiment, the appendage retraction tube is configured to be pulled in a proximal direction, and the ring-shaped element is configured to align the appendages against the appendage retraction tube subsequent to their passing through the defined space. 
     In an embodiment, the apparatus includes a retraction device, the appendage retraction tube includes silicone configured to be ensnared by the retraction device. 
     In an embodiment, the core catheter includes at least one support element. 
     In an embodiment, the at least one support element is configured to apply an anchoring force to a pyloric sphincter of the subject. 
     In an embodiment, the apparatus includes at least one rotatable coupling configured to couple the at least one support element to the core catheter, and the coupling is configured to deploy the at least one support element from a constricted state. 
     In an embodiment, the apparatus includes a skirt, the at least one support element is coupled to the skirt. 
     In an embodiment, the skirt is configured to be coupled to the core catheter and to the at least one support element, and the skirt is configured to be disposed at a site proximal to the gastric balloon. 
     In an embodiment, the skirt is configured to surround the gastric balloon at least in part. 
     In an embodiment, a distal-most end of the skirt is configured to be disposed at a site proximal to a proximal-most tip of the gastric balloon. 
     In an embodiment, the core catheter includes at least one pair of limbs. 
     In an embodiment, the at least one pair of limbs is disposed within the gastric balloon. 
     In an embodiment, the at least one pair of limbs is configured to be retracted within a lumen of the core catheter during insertion thereof, and to expand subsequent to insertion of the core catheter. 
     In an embodiment, the at least one pair of limbs is configured to be disposed at a distal end of the core catheter. 
     In an embodiment, the core catheter includes silicone at the distal end thereof, and the silicone bifurcates to form the at least one pair of limbs. 
     In an embodiment, the at least one pair of limbs is configured to be disposed at a proximal end of the core catheter. 
     In an embodiment, the core catheter includes silicone at the proximal end thereof, and the silicone bifurcates to form the at least one pair of limbs. 
     In an embodiment, the at least one pair of limbs is configured to restrict passage of the gastric balloon through a pyloric sphincter of the subject, should the core catheter invert within a stomach of the subject. 
     In an embodiment, the at least one pair of limbs is configured to function as an anchor. 
     In an embodiment, the anchor is configured to restrict passage of the gastric balloon through a pyloric sphincter of the subject. 
     In an embodiment, the apparatus includes a pushing tube configured to push the gastric balloon down the esophagus of the subject. 
     In an embodiment, the pushing tube is shaped to define at least one lumen configured for passage of the extension tube and inflation tube therethrough. 
     In an embodiment, the apparatus includes a core catheter coupled to the gastric balloon, the pushing tube includes an engaging element configured to engage the core catheter. 
     In an embodiment, the engaging element includes at least one resilient wire configured to engage a proximal end of the core catheter. 
     In an embodiment, the engaging element includes at least one control rod configured to engage a proximal end of the core catheter. 
     In an embodiment, the engaging element is configured to disengage from the core catheter once the gastric balloon is inserted into a stomach of the subject. 
     In an embodiment, a lateral surface of the pushing tube is shaped to define a first hole and a second hole. 
     In an embodiment, the apparatus includes a tube configured to inject a gas into a gastrointestinal lumen of the subject and to allow for auscultation identification of a presence of the gastric balloon in the stomach. 
     In an embodiment, the apparatus includes a verification balloon coupled to a distal end of the pushing tube, and an inflation tube configured to provide access via the second hole to inject fluid into the verification balloon. 
     In an embodiment, the verification balloon includes at least one balloon selected from the group consisting of: a Foley catheter balloon, a Blakemore tube balloon, and a Fogarty catheter balloon. 
     There is yet further provided, in accordance with an embodiment of the present invention, apparatus, including: 
     an intrabody device configured for insertion into a body of a subject; and 
     at least one projection coupled at at least a proximal end thereof to a site along the intrabody device, and configured to facilitate non-endoscopic extraction of the intrabody device from within the body of the subject. 
     In an embodiment, a distal end of the at least one projection includes a flexible, biocompatible material configured to enable atraumatic passage of the intrabody device during extraction thereof. 
     In an embodiment, the at least one projection includes silicone. 
     In an embodiment, the intrabody device is configured to reside entirely out of a gastrointestinal tract of the subject. 
     In an embodiment, the intrabody device is configured for entering a gastrointestinal tract of the subject. 
     In an embodiment, at least a portion of the intrabody device is configured to reside within the gastrointestinal tract of the subject. 
     In an embodiment, the apparatus includes an ensnaring device configured to ensnare the at least one projection, and the at least one projection includes a generally rigid material at the proximal end thereof which maintains coupling of the ensnaring device to the at least one projection as the intrabody device is removed from within the body of the subject. 
     In an embodiment, a distal end of the at least one projection is spaced apart from the intrabody device by a distance of at least 1 mm, and the ensnaring device is configured to loop around the distal end of the at least one projection and engage the proximal end thereof. 
     In an embodiment, the ensnaring device includes a polypectomy snare. 
     There is additionally provided, in accordance with an embodiment of the present invention, apparatus, including: 
     an intrabody device configured for insertion within a stomach of a subject; and 
     at least one appendage coupled to a site along the intrabody device, configured to stimulate a gastric wall of the subject. 
     In an embodiment, the at least one appendage is configured to stimulate satiety sensors in a fundus of the stomach of the subject. 
     In an embodiment, the intrabody device is configured to reside in an antrum of the stomach of the subject. 
     In an embodiment, the intrabody device is configured to reside in a fundus of the stomach of the subject. 
     In an embodiment, the at least one appendage is configured to function as a space-occupying device. 
     In an embodiment, the intrabody device includes an anchor. 
     In an embodiment, the apparatus includes a gastric balloon, and the intrabody device is coupled to the gastric balloon. 
     There is also provided, in accordance with an embodiment of the present invention, apparatus for use in a stomach of a subject, including: 
     a gastric balloon; 
     a hollow, flexible tube coupled at a distal end thereof to the gastric balloon, a proximal portion of the tube, when in a relaxed position, being shaped so as to prevent the balloon from passing into a duodenum of the subject; and 
     an inflation conduit disposed in part within the distal end of the tube, the inflation conduit exiting the tube at a site proximal to the gastric balloon. 
     In an embodiment, the inflation tube is configured to be pulled independently of the proximal portion of the flexible tube. 
     In an embodiment, the apparatus includes at least one cross-bar element having ends which are positioned in a vicinity of the proximal portion, and the cross-bar element is configured to help maintain a shape of the proximal portion. 
     In an embodiment, the cross-bar element is configured to inhibit compression of the shape of the proximal portion. 
     In an embodiment, the apparatus includes at least one elastic band having ends which are positioned in the vicinity of the proximal portion, wherein the at least one cross-bar element is shaped to define a hollow lumen for surrounding the at least one elastic band, and wherein the at least one elastic band is configured to inhibit straightening of the proximal portion. 
     The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic illustration of a mouth appliance coupled to inserting apparatus, in accordance with an embodiment of the present invention; 
         FIG. 1B  is a schematic illustration of an alternate configuration of the mouth appliance of  FIG. 1A , in accordance with an embodiment of the present invention; 
         FIGS. 2A and 2B  are schematic illustrations of the inserting apparatus of  FIG. 1A , and intrabody apparatus, in accordance with respective embodiments of the present invention; 
         FIGS. 3 ,  4 A; and  4 B are schematic illustrations of the intrabody apparatus of  FIGS. 2A and 2B , in accordance with respective embodiments of the present invention; 
         FIGS. 5A-5C  are schematic illustrations of non-endoscopically accessing the intrabody apparatus, in accordance with an embodiment of the present invention; 
         FIGS. 6A and 6B  are schematic illustrations of the intrabody apparatus comprising an intrabody device coupled to appendages, in accordance with respective embodiments of the present invention; 
         FIGS. 7A ,  7 B,  8 A, and  8 B are schematic illustrations of non-endoscopically accessing the intrabody apparatus of  FIGS. 2A and 2B , in accordance with respective embodiments of the present invention; 
         FIG. 9  is a schematic illustration of the intrabody apparatus of  FIGS. 2A and 2B , in accordance with an embodiment of the present invention; 
         FIGS. 10A-C  are schematic illustrations of the intrabody apparatus comprising an anchor, in accordance with respective embodiments of the present invention; 
         FIG. 11  is a schematic illustration of the intrabody apparatus of  FIGS. 2A and 2B , in accordance with another embodiment of the present invention; 
         FIGS. 12A and 12B  are schematic illustrations of the intrabody apparatus comprising at least one rotatable limb, in accordance with an embodiment of the present invention; 
         FIG. 13  is a schematic illustration of the intrabody apparatus comprising an anchor, in accordance with another embodiment of the present invention; 
         FIG. 14  is a schematic illustration of the intrabody apparatus of  FIGS. 10A-C , in accordance with another embodiment of the present invention; and 
         FIG. 15  is a schematic illustration of a gastric balloon coupled to an inflation tube and a flexible tube, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Reference is now made to  FIG. 1A , which is a schematic illustration of a system  20  comprising a mouth appliance  22  coupled to inserting apparatus  70 , in accordance with an embodiment of the present invention. System  20  is configured to provide non-endoscopic insertion and removal of intrabody apparatus. In some embodiments, the intrabody apparatus comprises a gastric balloon. In such embodiments, system  20  facilitates non-endoscopic inflation and deflation of the gastric balloon. 
     Inserting apparatus  70  comprises a pushing tube  36 , having a lumen containing an extension tube  30  coupled at a distal end thereof to a proximal end of an inflation tube  32 . Pushing tube  36  is configured to guide a non-inflated gastric balloon  38  into a body of a subject, typically when the subject is sedated. 
     Extension tube  30  is typically tethered to a prosthesis comprising mouth appliance  22 . Typically, extension tube  30  is coupled at a proximal end thereof to a luer-lock configured for passage of fluid therethrough in order to inflate gastric balloon  38 . In an embodiment, the luer-lock coupled to extension tube  30  is coupled to a string  42 , which in turn is coupled to mouth appliance  22 . Mouth appliance  22 , in turn, comprises one or more bilateral molds  24 , typically personalized according to the molars of lower teeth  28  of the subject. For some applications, bilateral molds  24  are interconnected by a “U” shaped connecting portion  26 , which adds stability and comfort to mouth appliance  22 . 
     Extension tube  30  is configured to remain disposed at least in part within an esophagus  34  of the subject, and coupled to mouth appliance  22 , to allow (if desired) for multiple outpatient inflations of gastric balloon  38  while the subject is awake. Gastric balloon  38  may be inflated, for example, a few times over a period of a few days or weeks while extension tube  30  is disposed within esophagus  34 . Subsequently, e.g., once gastric balloon  38  is at a desired level of inflation, extension tube  30  is extracted by removing mouth appliance  22  tethered thereto. Inflation tube  32 , still attached at its distal end to gastric balloon  38 , is pulled slightly out of the subject&#39;s mouth so that it can be capped. Inflation tube  32  is then placed into the posterior pharynx, to be passively retracted into stomach  41  of the subject. In the event that future inflations of gastric balloon  38  are indicated, inflation tube  32  is extracted from within stomach  41  using endoscopy, non-endoscopic methods described herein, or other methods. 
     In some embodiments of the present invention, during use of system  20  and initial insertion of gastric balloon  38 , a short-acting sedative (e.g., propofol) and/or a reversible drug (a benzodiazepine or a narcotic) is used to sedate the subject. Once gastric balloon  38  has successfully been inserted into the gastric lumen of the subject, the subject is revived by an antidote or due to the transient effects of the short-acting sedative. Gastric balloon  38  is then inflated via inflation tube  32  while the subject is conscious. A desired level of inflation of gastric balloon  38  is achieved based on feedback from the conscious subject. 
     Reference is now made to  FIG. 1B , which is a schematic illustration of mouth appliance  22 , in accordance with an embodiment of the present invention, with the exception that mouth appliance  22  comprises a mold  25  of the entire lower teeth  28 , typically customized according to the lower jaw of the subject. 
     In some embodiments, mouth appliance  22  comprises any mouth appliance that is configured to be employed within the mouth or pharynx, e.g., a bite plate or a single or multiple tooth mold/cap, configured to be tethered to extension tube  30 . 
     Reference is now made to  FIG. 2A , which is a schematic illustration of inserting apparatus  70  and intrabody apparatus  80 , in accordance with an embodiment of the present invention. Intrabody apparatus  80  comprises a core catheter  40  coupled at its distal end to gastric balloon  38 . Inflation tube  32  passes from the lumen of pushing tube  36  into a lumen of core catheter  40  and ends at an opening at a distal end of core catheter  40 ; the opening allows for fluid injected through inflation tube  32  to inflate gastric balloon  38 . Extension tube  30  is coupled to inflation tube  32  by a valve  43 . Valve  43  is configured to remain open during the duration in which extension tube  30  is coupled to inflation tube  32 , allowing for gastric balloon inflation from a location outside of the body of the subject. A cap (not shown) is placed on the proximal tip of extension tube  30  following an inflation of gastric balloon  38 . The cap is configured to be removed at each successive inflation (if desired) and subsequently replaced for the duration in which extension tube  30  is disposed within esophagus  34 . 
     Core catheter  40  typically comprises silicone at its proximal end  64 . For some applications, during initial insertion of gastric balloon  38 , proximal end  64  of core catheter  40  is pierced by or otherwise coupled to pointed distal pieces or non-pointed pieces of pushing tube  36 , creating a temporary coupling which allows pushing tube  36  to push intrabody apparatus  80  down esophagus  34  (configuration not shown). 
     In some embodiments, one or more (e.g., two) resilient, semi-rigid wires  54  and/or one or more (e.g., two) control rods  56  are fastened to the proximal end of pushing tube  36 , run the length of pushing tube  36 , and emerge at the distal end of pushing tube  36 . In order to connect wires  54  and/or control rods  56  to proximal end  64  of core catheter  40 , wires  54  reversibly ensnare proximal end  64  of core catheter  40 , and/or control rods  56  engage grooves on the proximal end  64  of core catheter  40 . The two wires  54  and/or the two rods are later disengaged from core catheter  40  by a releasing mechanism at the proximal end of pushing tube  36 . 
     In some embodiments of the present invention, core catheter  40  is shaped so as to provide a first lumen and a second lumen (not shown). Typically, the first lumen is configured for passage of inflation tube  32  therethrough. The second lumen is configured for passage therethrough of a guidewire  55  such as a standard guidewire, e.g., a standard 0.028 inch guidewire, as is known in the art. In some embodiments of the present invention, a rigid element, e.g., a straightening rod or a stiff guidewire, is passed through the second lumen. A distal end of guidewire  55  is located at the distal end of core catheter  40  and runs the entire length of both core catheter  40  and pushing tube  36 , thus providing rigidity to system  20  and facilitating steering thereof, as intrabody apparatus  80  is advanced through esophagus  34  and into stomach  41  of the subject. Typically, guidewire  55  comprises a resilient material, e.g., 316 LVM stainless steel, 304 stainless steel, nitinol, or PTFE coated 304 stainless steel. Once gastric balloon  38  is advanced into stomach  41 , guidewire  55  is removed. 
     Guidewires are known in the art for use in the upper gastrointestinal tract for dilating esophageal strictures. In an embodiment, known techniques such as those described in the above-mentioned articles by Kadakia S C et al., Fleischer D E et al., and/or Dumon J R et al., are modified, mutatis mutandis, for use with embodiments of the present invention, for example so as to facilitate passage of an esophageal dilator over a guidewire without the need for fluoroscopy. 
     In some embodiments of the present invention, pushing tube  36  has a circumference slightly larger than the circumference of proximal end  64  of core catheter  40 , such that pushing tube  36  slides over and surrounds proximal end  64  of core catheter  40 . Typically, the distal end of pushing tube  36  slides over proximal end  64  of core catheter  40  up to a predetermined location on core catheter  40  (typically the location of the attachment of gastric balloon  38 ). A stopping element  60  is configured to impede relative proximal motion of core catheter  40  within the lumen of pushing tube  36 , and prevent continued distal sliding of pushing tube  36  beyond the predetermined location. Typically, stopping element  60  comprises a baffle disposed within pushing tube  36  and/or limbs or an anchor disposed upon a surface of core catheter  40  at a location proximal to gastric balloon  38  (as shown hereinbelow with reference to  FIGS. 10A-C  and  12 A- 13 ). Stopping element  60  is disposed with respect to pushing tube  36  such that element  60  allows pushing tube  36  to slide along core catheter  40  enough so that pushing tube  36  covers, at least in part, any expandable element coupled to core catheter  40  (other than gastric balloon  38 ). 
     In some embodiments of the present invention, pushing tube  36  and core catheter  40  are shaped to provide identical diameters. In such an embodiment, a distal end of pushing tube  36  pushes a proximal end  64  of core catheter  40 . For this particular application, a distal sheath, described hereinbelow, is typically coupled to the distal end of pushing tube  36 . During insertion of intrabody apparatus  80 , the sheath covers the expandable elements of intrabody apparatus  80 . 
     Identifying that intrabody apparatus  80  is within the gastric lumen of the subject is accomplished by receiving feedback via a first opening  46  and a second opening  48  which are situated on a lateral portion of the distal end of pushing tube  36 . First opening  46  is typically but not necessarily located slightly distal to second opening  48 . The first and second openings are accessed by respective fluid-injection tubes  50  and  52  that run the length of pushing tube  36 . Each fluid-injection tube  50  and  52  comprises a Luer-lock port at its proximal end (not shown). Air is forcefully injected into the luer-lock port connected to tube  52  accessing first lateral opening  46  of pushing tube  36 , and is passed into the gastrointestinal lumen, allowing for identification of the presence (or absence) of intrabody apparatus  80  within the stomach, via auscultation. 
     Fluid-injection tube  50 , which accesses second opening  48 , is configured to inflate a verification balloon  44  (e.g., a Foley catheter balloon, a Fogarty catheter balloon, a Blakemore tube balloon, or an internal bumper of a percutaneous endoscopic gastrostomy (PEG) tube) encircling or otherwise coupled to the distal end of pushing tube  36 . In response to the auscultation indication of intrabody apparatus  80  being located within stomach  41  of the subject, verification balloon  44  is partially inflated, e.g., to approximately 150-200 cc. Pushing tube  36  is pulled back until the inflated verification balloon  44  is impeded by the gastroesophageal junction, thereby validating the location, within stomach  41 , of core catheter  40 . Gastric balloon  38  is then inflated and verification balloon  44  is deflated. 
     Pushing tube  36  is disengaged from proximal end  64  of core catheter  40 , following deflation of verification balloon  44 . As pushing tube  36  is extracted from the gastrointestinal tract of the subject, extension tube  30  and inflation tube  32  are typically left within esophagus  34  of the subject. Extension tube  30  is then coupled to mouth appliance  22  as described hereinabove with reference to  FIGS. 1A and 1B , allowing for multiple inflations of gastric balloon  38  during the time that extension tube  30  is disposed within the subject, if desired. 
     The caliber of inflation tube  32  and that of extension tube  30  are typically selected to be sufficient to allow relatively rapid inflation of gastric balloon  38 , for example, having an inner diameter of about 1-2 mm. (Tubes  30  and  32  typically have a wall thickness of about 0.5-1 mm.) Balloon  38  is inflated to a volume sufficient to partially fill the gastric lumen, e.g., to between about 400 cc and about 1000 cc, depending on stomach size. 
     In some embodiments of the present invention, extension tube  30  attached to inflation tube  32  is accessed endoscopically and withdrawn from the subject&#39;s mouth, allowing valve  43  of inflation tube  32  to be opened and closed while it is outside the subject&#39;s body, and leaving inflation tube  32  within esophagus  34  of the subject. 
     Reference is now made to  FIG. 2B , which is a schematic illustration showing inserting apparatus  70  and intrabody apparatus  80 , in accordance with an embodiment of the present invention. The embodiment shown in  FIG. 2B  is similar to that described hereinabove with reference to  FIG. 2A , with the exception that proximal end  64  of core catheter  40  comprises a pair of proximal limbs  58 . Proximal limbs  58  function to prevent passage of intrabody apparatus  80  through the pyloric sphincter of the subject should intrabody apparatus  80  invert within stomach  41  of the subject, as described hereinbelow with reference to  FIGS. 9 ,  10 C, and  11 . 
     Reference is now made to  FIGS. 2A and 2B . In an embodiment of the present invention, deployment of intrabody apparatus  80  described herein is performed while intrabody apparatus  80  is encased by a distal sheath (not shown), e.g., a sleeve, a gastric overtube known in the art, or equivalent. Typically, the distal sheath comprises a flexible, biocompatible material, e.g., silicone, which provides atraumatic insertion of system  20  into and along the gastrointestinal tract of the subject. Typically, a proximal end of the sheath is coupled to a distal portion of pushing tube  36  while the sheath extends distally over intrabody apparatus  80 . This standard, well-established technique is adapted for use with the novel techniques and devices described herein. Typically, the sheath maintains a closed configuration of intrabody apparatus  80  as it is introduced into the gastrointestinal tract of the subject and is passed into stomach  41  of the subject. Pushing tube  36  is then disengaged from intrabody apparatus  80  and is subsequently extracted from within the body of the subject. As pushing tube  36  is being extracted, the sheath is slid proximally along intrabody apparatus  80  and is removed from the stomach thus allowing intrabody apparatus  80  to assume an open, relaxed configuration. 
     Reference is now made to  FIG. 3 , which is a schematic illustration of core catheter  40  comprising finger-like projections  66 , in accordance with an embodiment of the present invention. The silicone at proximal end  64  of core catheter  40  typically but not necessarily comprises three to six finger-like projections  66 , which project distally and outwardly from proximal end  64  of core catheter  40 . Finger-like projections  66  are typically but not necessarily spaced several millimeters apart from one another (e.g., 4 mm apart) around the circumference of core catheter  40 . Projections  66  typically comprise a soft tip, e.g., silicone or any such other material known in the art, which enables atraumatic passage of projections  66  through the gastrointestinal tract of the subject. 
     Finger-like projections  66  enable the ensnaring of core catheter  40  by an extraction device (e.g., a polypectomy snare, pushing tube  36 , a nasogastric tube  72 , hook catheter, grabbing forceps, or any other tube configured to retract core catheter  40  from within stomach  41 ). 
     Typically, a distal end  68  of each projection  66  is spaced apart from the body of core catheter  40  at a distance of about 1 mm. For applications in which a polypectomy snare (or any other looped tool known in the art) is used in order to extract intrabody apparatus  80  from within stomach  41  of the subject, the polypectomy snare slides around distal end  68  of projection  66  and advances toward a proximal end  69  of projection  66  until the polypectomy snare is impeded by the junction between core catheter  40  and proximal end  69 . Typically, proximal end  69  of each projection  66  comprises a rigid material, e.g., a metal such as nitinol or stainless steel, which maintains the coupling of the extraction device to projections  66  as intrabody apparatus  80  is being extracted from within stomach  41  of the subject. The rigid material is typically encased by a softer material, such as silicone. 
     It is to be noted that the location of projections  66  at proximal end  64  of core catheter  40  is by way of illustration and not limitation. In some embodiments, projections  66  are located at any suitable location along core catheter  40 , e.g., coupled to a middle portion of core catheter  40 . For some applications, proximal end  64  comprises a silicone crown, described hereinbelow with reference to  FIG. 13 , which is typically but not necessarily generally hyperbolic in shape, looking like crown  175  in  FIG. 13 . For this particular application, projections  66  are coupled at proximal ends thereof to the crown, while their distal ends extend away from the crown. 
     Reference is now made to  FIGS. 4A and 4B , which are schematic illustrations of intrabody apparatus  80  comprising an intrabody device  47 , e.g., core catheter  40 , coupled to a plurality of appendages  62 , in accordance with an embodiment of the present invention. Typically, appendages  62  are between 4 cm and 12 cm (e.g., 8-12 cm) in length, and comprise a flexible and durable biocompatible material (e.g., nitinol, silicone, or another known synthetic material), configured to withstand the acid environment of the stomach. Typically, distal ends of appendages  62  are coupled to proximal end  64  of core catheter  40 , and during initial insertion of intrabody apparatus  80 , the proximal ends of appendages  62  are disposed within pushing tube  36 . Such a configuration allows for atraumatic passage of appendages  62  through esophagus  34  of the subject. Following initial insertion of intrabody apparatus  80  within stomach  41 , pushing tube  36  is extracted from the body of the subject, exposing appendages  62  which project from proximal end  64  of core catheter  40  toward the fundus  61  of stomach  41 . 
     Appendages  62  stimulate satiety sensors in fundus  61 , which induces increased satiety of the subject in combination with inserted gastric balloon  38 . Alternatively, appendages  62  are utilized in the absence of gastric balloon  38 . In some embodiments, appendages  62  project from a surface of gastric balloon  38 . Appendages  62  assume a configuration, e.g., wavy or straight, that allows for appendages  62  to flex in a plurality of directions. The ability of appendages  62  to flex protects surrounding tissue of esophagus  34  from being damaged as intrabody apparatus  80  is being inserted into stomach  41 . For some applications, each appendage  62  is coupled to core catheter  40  by a hinge. For some applications, appendages  62  are retracted into the lumen of core catheter  40 . 
     Typically, appendages  62  comprise a biocompatible, atraumatic material, e.g., silicone. In some embodiments, in order to maintain resiliency of appendages  62  as they project toward fundus  61 , a resilient wire is disposed within and extends throughout each appendage  62 . The wire itself is typically configured to flex at the junction at which each appendage  62  is coupled to core catheter  40 . For example, each appendage  62  may be coupled to core catheter  40  by a hinge. In some embodiments, the wire disposed within each appendage  62  is configured to flex only at the coupling junction. Typically, appendages  62  are long enough to stimulate fundus  61  of stomach  41  even when intrabody apparatus  80  migrates toward the antrum of stomach  41 . 
     For some embodiments in which intrabody apparatus  80  migrates toward the antrum of stomach  41 , appendages  62  stimulate the antrum of stomach  41 . 
     For some applications, appendages  62  are also space-occupying objects configured to induce a sense of satiety of the subject. 
     In some embodiments, a first portion and a second portion of appendages  62  project in opposite directions. For example, the first portion of appendages  62  may project toward fundus  61 , while a second portion of appendages  62  may project toward the antrum of stomach  41 . In such an embodiment, the first and second portions of appendages  62  are disposed upon inflation tube  32  and/or core catheter  40  at respective proximal and distal ends thereof. 
     It is to be noted that appendages  62  may be disposed in any suitable configuration and/or at any suitable location along inflation tube  32  and/or core catheter  40 . For example, the first portion of appendages  62  may be disposed symmetrically with respect to the second portion of appendages  62 . 
     Reference is now made to  FIGS. 5A ,  5 B, and  5 C, which are schematic illustrations of non-endoscopically accessing intrabody apparatus  80 , in accordance with an embodiment of the present invention. Intrabody apparatus  80  comprises an intrabody device  49 , e.g., an appendage retraction tube  132 , coupled to appendages  62 . Typically, appendage retraction tube  132  is disposed within a lumen of core catheter  40 . 
     Proximal end  64  of core catheter  40  is coupled to at least two columns  130 , e.g., four columns (as shown). The distal ends of columns  130  are coupled to proximal end  64  of core catheter  40  while proximal ends of columns  130  are coupled to and support a ring-shaped element  134 , thereby defining a space between proximal end  64  of core catheter  40  and ring-shaped element  134 . Appendages  62  are configured to emanate from within core catheter  40 , and through the defined space. For this application, appendages  62  are coupled, at distal ends thereof, to any suitable location along appendage retraction tube  132 , while their proximal ends run through ring-shaped element  134 , project toward, and stimulate gastric cardia and fundus  61 . 
     Appendage retraction tube  132  typically comprises silicone at its proximal end. As shown, the silicone at the proximal end of appendage retraction tube  132  is shaped to define a slit through which a suitable retraction device  136  (as described hereinabove with reference to the extraction device of  FIG. 3 ) engages tube  132 . For some applications, the silicone at the proximal end of appendage retraction tube  132  comprises finger-like projections which project distally from the proximal end of appendage retraction tube  132 . These finger-like projections enable ensnaring of appendage retraction tube  132  by the retraction device  136 . In another embodiment, the silicone at the proximal end of appendage retraction tube  132  is shaped to define a ball which enables ensnaring thereof by an extraction device, as described hereinbelow with reference to  FIG. 13 . Typically, the ball is reinforced by a metal insert which maintains rigidity of the ball during ensnaring of appendage retraction tube  132  and extraction thereof from the body of the subject. 
     Typically, appendage retraction tube  132  is reversibly coupled to core catheter  40  such that once retraction device  136  engages appendage retraction tube  132 , the physician applies a slight force in order to disengage appendage retraction tube  132  from core catheter  40 . 
     Appendage retraction tube  132  is pulled in a proximal direction toward esophagus  34 , through ring-shaped element  134 , while the fundus-contacting tips of appendages  62  are simultaneously pushed in a distal direction by ring-shaped element  134  and are drawn closer to core catheter  40 . Appendage retraction tube  132  is pulled through ring-shaped element  134  and the distal ends of appendages  62  are concomitantly pulled through the defined space and subsequently through ring-shaped element  134 . Ring-shaped element  134  thus facilitates alignment of appendages  62  alongside the length of appendage retraction tube  132 , and enables atraumatic retraction of appendages  62  from stomach  41  of the subject. 
       FIGS. 6A and 6B  illustrate intrabody apparatus  80  comprising an intrabody device  51 , e.g., an anchor  1 , coupled to a plurality of appendages  262 , in accordance with respective embodiments of the present invention. Anchor  1  has a distal end  2 , a proximal end  4 , and a side wall  5 . The distal end is typically tapered for ease of insertion. Proximal end  4  is shaped so as to define an aperture  6  opening into a central core, which extends through substantially the entire length of the anchor. The distal end may be either open or closed. A rigid insertion rod (not shown) is inserted into aperture  6  and the central core during insertion of anchor  1  into the patient. Anchor  1  is made of a material that is flexible enough to be straightened, but has an elastic memory to conform to a pre-selected bent shape. The elastic memory may be imparted by the material itself, or alternatively, by the addition of another material. For example, the shape to which the anchor reverts may be determined by the inclusion of an additional material having a memory, such as spring steel or a plastic insert. The anchor material comprises a biocompatible material that can withstand the acid environment of the stomach, as is well known to those skilled in the art. 
     A guidewire canal  12  is typically formed in the wall of anchor  1  for inserting a guidewire during insertion of the anchor into the stomach. Alternatively, an overtube may be used in lieu of a guidewire during insertion of the anchor into the gastrointestinal tract. If the diameter of the anchor is sufficiently small, a biopsy channel of an endoscope may be used as an overtube to direct the anchor into the gastrointestinal tract. 
     Anchor  1  is shown having a “U” shape, however it is to be noted that anchor  1  may assume a “C”, “S”, or any other pre-selected bent shape that the anchor has been configured to assume. Appendages  262  comprise one or more elements which may comprise, for example, silicone, cord (e.g., suture), ribbon, sponges, other thin material, or a combination thereof. Appendages  262  typically comprise a biocompatible material, as described hereinabove with reference to appendages  62  of  FIGS. 4A-5C . Appendages  262  are adapted to occupy all or a portion of the antrum, thereby interfering with gastric emptying. 
     For some applications, and as shown in  FIG. 6A , appendages  262  are used in lieu of gastric balloon  238 . In these applications, appendages  262  may be coupled to a central portion of anchor  1 , for example. Alternatively, for some applications, as shown in  FIG. 6B , appendages  262  are used in combination with balloon  238 . In these applications, appendages  262  may be coupled to a lateral arm of anchor  1 , for example. 
     Anchor  1 , when in the U-configuration, typically has a total length of between about 30 and about 55 cm, e.g., approximately 40 cm. A central, generally straight, portion typically has a length of between about 15 and about 25 cm, e.g., approximately 16 cm or approximately 20 cm, and each end portion typically has a length of between about 8 and about 15 cm, e.g., approximately 10 cm or approximately 12 cm. These dimensions may, of course, vary depending on stomach shape and size. Other areas of the gastrointestinal tract utilize various shapes and sizes. Typically, distal end  2  of anchor  1  is closed and is tapered with a soft flexible tip to allow easy passage through the gastrointestinal tract. 
     Techniques described herein may be used in combination with techniques described in: 
     PCT Patent Publication WO 07/110866 to Brooks, filed Mar. 28, 2007, entitled “Floating gastrointestinal anchor”; 
     U.S. Provisional Patent Application 60/787,124 to Brooks, filed Mar. 28, 2006, entitled, “Floating gastrointestinal anchor”; and 
     U.S. Provisional Patent Application 60/815,624 to Brooks, filed Jun. 21, 2006, entitled, “Floating gastrointestinal anchor.” Each of these applications is incorporated herein by reference. 
     Reference is now made to  FIG. 7A , which is a schematic illustration of non-endoscopically accessing inflation tube  32  from within stomach  41 , in accordance with an embodiment of the present invention. Inflation tube  32  is non-endoscopically extracted from within stomach  41 , when further inflation of gastric balloon  38  is desired. Inflation tube  32  is coupled to an accessing device comprising one or more hook-and-loop fasteners  90  (e.g., Velcro strips) or other connection-facilitating elements. Inflation tube  32  is accessed when an extraction device such as a nasogastric tube  72  comprising hook-and-loop fasteners  90  at its distal tip successfully hooks and fastens to hook-and-loop fasteners  90  coupled to inflation tube  32 . 
     Typically, hook-and-loop fasteners  90  are coupled to inflation tube  32  in the vicinity of valve  43 , e.g., proximal thereto (as shown), and comprise loops  94 . Hook-and-loop fasteners  90  coupled to nasogastric tube  72  comprise hooks  96  which ensnare loops  94  of the hook-and-loop fasteners coupled to inflation tube  32 . 
     In some embodiments, hook-and-loop fasteners  90  are disposed within a lumen of nasogastric tube  72 , and are expanded therefrom once nasogastric tube  72  has entered stomach  41 . Once expanded, hook-and-loop fasteners  90  are arranged such that at least a portion of hook-and-loop fasteners  90  of nasogastric tube  72  align with hook-and-loop fasteners  90  coupled to inflation tube  32 . 
     During initial insertion of intrabody apparatus  80 , hook-and-loop fasteners  90  of inflation tube  32  are retracted within a lumen of inflation tube  32  and emerge therefrom once inflation tube  32  has been disconnected from extension tube  30  and allowed to retract into stomach  41  of the subject. In some embodiments, hook-and-loop fasteners  90  of inflation tube  32  are coupled to an outer surface of inflation tube  32  and are disposed within pushing tube  36  during initial insertion of intrabody apparatus  80 . Once pushing tube  36  is extracted from within the body of the subject, hook-and-loop fasteners  90  of inflation tube  32  are exposed and are allowed to expand. Following detachment of extension tube  30  from inflation tube  32  as described hereinabove, a cap  74  is placed on the proximal tip of inflation tube  32  proximal to hook-and-loop fasteners  90 , prior to its retraction into stomach  41  of the subject. 
     Reference is now made to  FIG. 7B , which is a schematic illustration of the hook-and-loop fasteners  90  of nasogastric tube  72 , as described hereinabove with reference to  FIG. 7A , with the exception that hook-and-loop fasteners  90  of nasogastric tube  72  are disposed in an array upon a carrier balloon  76 . During the passing of nasogastric tube  72  through esophagus  34 , carrier balloon  76  is retracted within the lumen of nasogastric tube  72 . Once inside stomach  41 , carrier balloon  76  expands from within the lumen, exposing hook-and-loop fasteners  90  and enabling their accessing of hook-and-loop fasteners  90  coupled to inflation tube  32 . 
     Reference is now made to  FIG. 8A , which is a schematic illustration of non-endoscopically accessing inflation tube  32  from within stomach  41 , in accordance with another embodiment of the present invention. Inflation tube  32  comprises an accessing device comprising a net  84  coupled to a site in a vicinity of the proximal end of inflation tube  32 . Typically, net  84  is arranged in a planar configuration, extending up to 360 degrees circumferentially around inflation tube  32 . Once nasogastric tube  72  has successfully entered stomach  41 , inflation tube  32  is non-endoscopically accessed by an extraction device comprising a hooking mechanism  82  which expands from a retracted state within the lumen of nasogastric tube  72  and is configured to hook net  84 . Net  84  comprises a flexible and durable biocompatible material, e.g., nitinol, silicone, or another synthetic material. 
     Reference is now made to  FIG. 8B , which is a schematic illustration of system  20  comprising a device for non-endoscopically accessing inflation tube  32  from within stomach  41 , as described hereinabove with reference to  FIG. 8A , with the exception that net  84  is arranged in a spherical configuration with respect to inflation tube  32 , in accordance with an embodiment of the present invention. Net  84  is a space-filling device which provides added area in which hook  82  can engage net  84 . 
     Reference is now made to  FIGS. 7A-8B . In some embodiments of the present invention, a short-acting sedative (e.g., propofol) and/or reversible narcotic (e.g., benzodiazepine or narcotics), is used to sedate the subject for the period of time that inflation tube  32  is accessed from within stomach  41  of the subject. Once inflation tube  32  has successfully been extracted from the gastric lumen of the subject, the subject is revived by an antidote or due to the transient effects of the short-acting sedative. Gastric balloon  38  is then inflated via inflation tube  32  while the subject is conscious. A desired level of inflation of gastric balloon  38  is achieved based on feedback from the conscious subject. 
     For some applications, net  84  comprises a mesh. 
     Reference is now made to  FIG. 9 , which is a schematic illustration of core catheter  40  comprising a pair of proximal limbs  58  and a pair of distal limbs  102 . During the insertion procedure, proximal limbs  58  and distal limbs  102  are secured together in a closed configuration to allow for atraumatic passage of core catheter  40  through esophagus  34  of the subject. During insertion and withdrawal of intrabody apparatus  80  from stomach  41 , limbs  58  and  102  are retracted within the lumen of core catheter  40 , thereby assuming the closed configuration. In some embodiments, proximal limbs  58  assume the closed configuration by being disposed within pushing tube  36  during insertion of intrabody apparatus  80 , while distal limbs  102  are surrounded by the distal sheath described hereinabove with reference to  FIG. 2A . Upon identifying that core catheter  40  has entered the gastric lumen of the subject, as described hereinabove, limbs  58  and  102  are extended from within the lumen of core catheter  40  and assume an open configuration thereof. 
     Limbs  58  and  102  function as “Y”-shaped anchors, minimizing the possibility for passage of intrabody apparatus  80  through pyloric sphincter  45  of the subject. Proximal limbs  58  are configured to prevent intrabody apparatus  80  from passing through pyloric sphincter  45 , should intrabody apparatus  80  invert within stomach  41 . 
     Gastric balloon  38  is disposed on the surface of core catheter  40  at a location between proximal limbs  58  and distal limbs  102 . Typically, gastric balloon  38  is wrapped around core catheter  40  during insertion thereof, and is unwrapped upon entering stomach  41  of the subject. For some applications, gastric balloon  38  is wrapped around core catheter  40  by a material configured to dissolve and release gastric balloon  38  upon entering stomach  41  of the subject. In some embodiments, gastric balloon  38  is surrounded by the distal sheath described hereinabove with reference to  FIG. 2A . 
     Reference is now made to  FIGS. 10A-C , which are schematic illustrations of core catheter  40  comprising an anchor  120  which comprises a skirt  122 , in accordance with respective embodiments of the present invention. Typically, skirt  122  is reinforced by one or more support elements. Typically, the support elements, once deployed within stomach  41  of the subject, have a tendency to assume an open configuration which restricts passage of intrabody apparatus  80  through pyloric sphincter  45  should balloon  38  deflate at least partially and migrate thereto. For some applications, a distal end of skirt  122  surrounds at least a portion of gastric balloon  38  (configuration not shown). In an embodiment, skirt  122  comprises silicone or another flexible material, which stretches as a consequence of inflation of gastric balloon  38 . 
     Typically, the support elements of anchor  120  flex less than 90 degrees toward proximal end  64  of core catheter  40  due to the resistance of skirt  122  against the support elements. For some applications, anchor  120  comprises a tether at the distal end of the two or more support elements, which is fastened to gastric balloon  38  or to core catheter  40 . The length of the tether is typically such that it allows the distal end of the two or more bars to rotate no more than 90 degrees away from core catheter  40 . 
     During extraction of intrabody apparatus  80 , the gastroesophageal junction of the subject impedes anchor  120 , thus drawing anchor  120  into a closed configuration by aligning expandable portions of anchor  120  alongside core catheter  40 . Such alignment enables atraumatic extraction of intrabody apparatus  80 . 
     As shown in  FIG. 10A , three support elements, e.g., limbs  160 , support an inner surface of skirt  122 . It is to be noted that three limbs are shown by way of illustration and not limitation, and that more than two limbs may be used. Typically, limbs  160  are coupled to core catheter  40  by a coupling, e.g., a hinge, a spring, or a shape-memory alloy. Typically, limbs  160  extend from a proximal end to a distal end of anchor  120  and are coupled to skirt  122 . Typically, limbs  160  comprise a semi-firm material configured to flex, but not bend fully. 
       FIG. 10B  shows anchor  120  comprising support elements, e.g., bars  124 , in accordance with an embodiment of the present invention. Typically, bars  124  are disposed at an outer surface of skirt  122 , and are coupled to a ring which surrounds core catheter  40 . 
       FIG. 10C  shows anchor  120  comprising support elements, e.g., limbs  160 , in accordance with an embodiment of the present invention. In this particular embodiment, limbs  160  extend from and are flush with the material of core catheter  40 . As shown, skirt  122  is pleated in this particular embodiment. 
     Reference is now made to  FIG. 11 , which is a schematic illustration of core catheter  40  as described hereinabove with reference to  FIG. 9 , with the exception that both distal limbs  102  and gastric balloon  38  are disposed at a distal end  100  of core catheter  40 , in accordance with an embodiment of the present invention. During insertion of intrabody apparatus  80 , gastric balloon  38  is wrapped around limbs  102 , thereby maintaining limbs  102  in a closed configuration. As gastric balloon  38  is inflated, it unwraps from around limbs  102  and forms a cavity in which distal limbs  102  are allowed to expand. Distal limbs  102  prevent migration of intrabody apparatus  80  through pyloric sphincter  45  should gastric balloon  38  deflate. In the event of gastric balloon  38  flipping in a proximal direction, proximal limbs  58  function as the anchors that restrict migration of intrabody apparatus  80  through pyloric sphincter  45 . 
     Reference is now made to  FIG. 12A , which is a schematic illustration of core catheter  40  comprising at least one rotatable limb  140  (e.g., a first limb  141  and a second limb  142 , as shown) disposed at a location proximal to gastric balloon  38 , in accordance with an embodiment of the present invention. It is to be noted that although two limbs  140  are illustrated, core catheter  40  may be coupled to, for example, one, two, or three limbs. Rotatable limbs  140  comprise a soft, resilient, biocompatible material, e.g., silicone or any such other material known in the art, which facilitates atraumatic passage of intrabody apparatus  80  within the gastrointestinal tract of the subject. Typically, rotatable limbs  140  are between 3 cm and 8 cm in length, and are coupled to core catheter  40  via a coupling  92 , e.g., a hinge or a stainless steel spring, or are formed as an extension of core catheter  40 . In some embodiments, limbs  140  are coupled to core catheter  40  via a shape-memory alloy, which allows limbs  140  to expand to a predefined shape once intrabody apparatus  80  is within stomach  41  of the subject. 
     As described hereinabove, in some embodiments, pushing tube  36  has a circumference slightly larger than the circumference of the proximal end  64  of core catheter  40 . Pushing tube  36  slides over and surrounds proximal end  64  of core catheter  40  and limbs  140 , such that they align with core catheter  40 . When limb  141  is aligned with core catheter  40  during insertion and extraction of intrabody apparatus  80 , the distal-most tip of limb  141  aligns with core catheter  40  at a location proximal to a proximal-most junction  144  between balloon  38  and core catheter  40 . Such a configuration reduces interference between balloon  38  and limbs  140  during deployment of intrabody apparatus  80  once in stomach  41  of the subject. 
     Couplings  92  are configured to expand limbs  140  by rotating them counter-clockwise (in the example shown in the figure). A first of the two couplings  92  expands first limb  141  in a distal to proximal direction. Such rotation enables limb  141  to function as an anchor should balloon  38  deflate within stomach  41  and intrabody apparatus  80  migrate toward pyloric sphincter  45 . A second of the two couplings  92  expands second limb  142  in a proximal to distal direction once within stomach  41  of the subject. Second limb  142  functions as an anchor should intrabody apparatus  80  rotate within stomach  41  of the subject. 
     Reference is now made to  FIG. 12B , which is a schematic illustration of core catheter  40  comprising at least one rotatable limb  140  (e.g., two limbs  141  and  142 , as shown), disposed at a location proximal to gastric balloon  38  as described hereinabove with reference to  FIG. 12A , with the exception that both couplings  92  rotate in different directions, in accordance with an embodiment of the present invention. When limbs  140  are aligned with core catheter  40  during insertion and extraction of intrabody apparatus  80 , the distal-most tips of respective limbs  141  and  142  align with core catheter  40  at a location proximal to a proximal-most junction  144  between balloon  38  and core catheter  40 . 
     During deployment of intrabody apparatus  80  within stomach  41  of the subject, a first of the two couplings  92  shown rotates in a counter-clockwise direction in order to expand first limb  141  in a distal to proximal direction. A second of the two couplings  92  is configured to rotate in a clockwise direction, expanding the second limb in a distal to proximal direction. In this embodiment, should balloon  38  deflate within stomach  41 , both limbs  140  function as anchors, minimizing passage of intrabody device  80  through pyloric sphincter  45  by applying an anchoring force thereto. 
     Reference is now made to  FIG. 13 , which is a schematic illustration of intrabody apparatus  80  comprising a longitudinal anchor  172 , in accordance with an embodiment of the present invention. Anchor  172  is shaped so as to define a hole or slit configured to surround core catheter  40 . The hole enables lateral sliding motion of anchor  172  about the longitudinal axis of core catheter  40 . 
     A pair of limbs  170  coupled to core catheter  40  and to lateral ends of anchor  172  facilitate retraction and expansion of anchor  172  during respective insertion and deployment thereof. Typically, anchor  172  comprises a flexible, biocompatible material, e.g., silicone or any other suitable material known in the art, thus enabling anchor  172  to achieve a refracted state by compression thereof during insertion and extraction of intrabody apparatus  80  from within stomach  41  of the subject. Typically, a sleeve (described hereinabove) or pushing tube  36  surrounds intrabody apparatus  80  during insertion thereof and aligns limbs  170  along core catheter  40 . Aligning limbs  170  with core catheter  40  draws together the lateral-most ends of anchor  172 , thus compressing anchor  172 . Limbs  170  are reinforced by a resilient or rigid material, e.g., a metal strip or a wire, which stabilizes and supports anchor  172  should anchor  172  apply an anchoring force to pyloric sphincter  45 . 
     In the embodiment shown in  FIG. 13 , proximal end  64  of core catheter  40  comprises a crown  175 . In some embodiments, projections  66 , described hereinabove with reference to  FIG. 3 , are coupled to crown  175  to facilitate extraction of intrabody apparatus  80  from within stomach  41 . 
     Alternatively or additionally, proximal end  64  of core catheter  40  is coupled to a cap  174 . Cap  174  typically comprises a flexible, biocompatible material, which enables atraumatic extraction of intrabody apparatus  80  from within stomach  41  of the subject. Cap  174  is typically but not necessarily reinforced by a rigid material  176 , e.g., a metal or a wire, which supports cap  174  during extraction thereof. Typically, rigid material  176  forms a ball  178  at a proximal-most tip of cap  174 , which provides rigidity to cap  174  during ensnaring by an extraction device, e.g., a polypectomy snare or any other extraction device described hereinabove. 
     Additionally, a proximal end of inflation tube  32  is disposed within cap  174 . Cap  174  is removably coupled to core catheter  40  such that following ensnaring of cap  174  and application of a proximal force thereto, cap  174  detaches from core catheter  40 . When cap  174  is extracted, inflation tube  32  is concomitantly pulled therewith. Extraction of cap  174  from within the body of the subject exposes valve  43  at the proximal end of inflation tube  32 . Valve  43  is then opened and a fluid is injected therethrough in order to inflate gastric balloon  38 , which remains disposed within stomach  41  of the subject. 
     Reference is now made to  FIGS. 9-13 . For some applications, core catheter  40  comprises silicone at its proximal end  64  and distal end  100 . The silicone at either end is configured to bifurcate and provide “Y”-shaped proximal limbs  58  and distal limbs  102 , which function in a manner as described hereinabove with reference to  FIGS. 9-13 . 
     Upon insertion of intrabody apparatus  80 , a closed configuration of limbs  58  and  102  is achieved by wrapping gastric balloon  38  around either pair of the two limbs (not shown); gastric balloon  38  is configured to be unfolded and to release limbs  58  and  102  upon entering stomach  41  of the subject. 
     For some applications, limbs  58  and  102  are reversibly secured together by wrapping the limbs in material configured to dissolve upon entering stomach  41  of the subject. 
     For some applications, upon withdrawal of intrabody apparatus  80  from within stomach  41 , each pair of limbs  58  and  102  is drawn into a closed configuration by a snare that is inserted (e.g., via endoscopy, or without vision) into stomach  41  from a location outside of the body of the subject. The snare engages both limbs of either the proximal pair  58  or distal pair  102  of limbs to enable extraction of intrabody apparatus  80 . 
     It is to be noted that, by way of illustration and not limitation, both proximal limbs  58  and distal limbs  102  are shaped to define a “Y”-shaped anchor. The anchor can be coupled to core catheter  40  at any suitable location. Once inside stomach  41 , the anchor typically expands  60  to 90 degrees from core catheter  40 . 
     Reference is now made to  FIG. 14 , which is a schematic illustration of core catheter  40  comprising a proximal anchor  220  and a distal anchor  320 , each comprising a skirt  122 , in accordance with an embodiment of the present invention. Except as described, the embodiment shown in  FIG. 14  is typically configured for use in combination with any of the embodiments described hereinabove with reference to  FIGS. 1-13 . Anchors  220  and  320  comprise a soft, biocompatible skirt  122  which is reinforced by support elements, e.g. limbs  160 . Core catheter  40  comprises at least one limb  160 , e.g., two limbs  160  (as shown). Once deployed within stomach  41  of the subject, limbs  160  have a tendency to assume an opened configuration which restricts passage of intrabody apparatus  80  through pyloric sphincter  45 . Typically, distal skirt  320  restricts passage of intrabody apparatus  80  through pyloric sphincter  45 ; should intrabody apparatus  80  rotate within stomach  41 , proximal skirt  220  at least partially blocks pyloric sphincter  45  thus preventing migration of intrabody apparatus  80  therethrough. 
     Typically, limbs  160  of anchors  220  and  320  extend from and are flush with the material of core catheter  40 . Typically, anchors  220  and  320  are configured to flex less than 90 degrees away from respective proximal and distal ends of core catheter  40 , restricted from further flexing due to the pressure exerted by the stretched skirt. In some embodiments, this pressure occurs when substances within the stomach gather within skirt  122  of proximal anchor  220 . Such pressure pushes intrabody apparatus  80  toward the antrum of stomach  41 , allowing distal anchor  320  to apply an anchoring force to pyloric sphincter  45  should intrabody apparatus  80  migrate thereto. 
     It is to be noted that proximal anchor  220  and distal anchor  320  may be used in combination with or independently of gastric balloon  38 , and may function as space-filling objects themselves. 
     Reference is now made to  FIG. 15 , which is a schematic illustration of a system  200  comprising a core catheter  202  and a gastric balloon  220  sealed along a portion of catheter  202  in a vicinity of a distal end  206  thereof, in accordance with an embodiment of the present invention. Core catheter  202  is shaped to define a hollow lumen  212  for passage therethrough of at least a portion of an inflation tube  230 . A distal portion and distal end  206  of core catheter  202  is disposed within balloon  220 , while the remaining portion of catheter  202  is disposed outside balloon  220 . Core catheter  202  exits balloon  220  at only one location thereof, i.e., a proximal opening  222  of balloon  220 . In such an embodiment, balloon  220  has only one opening, as shown. 
     Core catheter  202  comprises a flexible, tubular material, e.g., silicone, having an elastic memory for assuming a relaxed, pre-selected bent configuration, as shown. 
     Inflation tube  230  comprises an elastic material, e.g., silicone, and has a proximal end  232  coupled to a luer-lock port  236 . Typically, a distal portion of inflation tube  230  is disposed within core catheter  202  while the remaining portion of inflation tube  230  is disposed outside catheter  202 . Inflation tube  230  exits core catheter  202  though an opening  216  in catheter  202  at a site proximal to proximal opening  222  of balloon  220 , and, for some applications, distal to the curve of a “U”-shaped portion  208  of catheter  202 . 
     Catheter  202  comprises an open proximal end  204  having a central lumen  212  extending toward distal end  206 . During the initial advancement and positioning of system  200  within the stomach of the subject, lumen  212  receives a straightening rod therethrough and catheter  202  is straightened from its pre-selected bent shape. During the advancement of system  200  toward the stomach, balloon  220  is in a deflated state. System  200  is advanced toward the stomach of the subject balloon-first so as to facilitate atraumatic advancement of system  200  toward the stomach. During the advancement, inflation tube  230  is advanced alongside and in parallel with core catheter  202 . 
     Once positioned within the stomach of the subject, the straightening rod is removed, and thereby core catheter  202  is allowed to assume its relaxed, pre-selected bent configuration (as shown). This pre-selected bent configuration enables catheter  202  to function as an anchor in order to prevent migration of system  200  through the pyloric sphincter. As catheter  202  assumes its bent configuration, the proximal portion of inflation tube remains disposed outside catheter  202  in a resting position thereof. A distal end  234  of inflation tube  230  is exposed from within core catheter  202  through an opening  207  defined in the portion of catheter  202  that is disposed within balloon  220 . Once system  200  is positioned within the stomach of the subject, fluid (e.g., liquid such as saline, air, or gas), foam, or any other filler known in the art is injected via luer-lock port  236  through inflation tube  230 , in order to inflate balloon  220 , as described hereinabove with reference to  FIG. 1A . 
     During the initial and subsequent inflations of balloon  220 , the proximal portion of inflation tube  230  is accessed endoscopically or non-endoscopically and is pulled from its resting position toward the mouth of the subject. As it is pulled, inflation tube  230  is stretched (as shown), and is pulled independently of core catheter  202 , which continues to maintain its pre-selected bent configuration during the pulling of inflation tube  230 . In some embodiments, inflation tube  230  is stretched to more than 2.5 times its resting position length in order to facilitate inflation of balloon  220  from a site outside the body of the subject. 
     The portion of catheter  202  that is disposed outside of balloon  220  is shaped to define “U”-shaped portion  208  and a pigtail, helical portion  210 . It is to be noted that these shapes are shown by way of illustration and not limitation, and that core catheter  202  may assume any given shape, e.g., an “S”-shape. 
     A cross-bar element  214  is shown bridging opposing portions of portion  208  of catheter  202  in a relaxed state thereof. Although one cross-bar element  214  is shown, it is to be noted that two or more cross-bar elements may be coupled to catheter  202  at any location along portions  208  and/or  210  of catheter  202 . 
     Cross-bar element  214  comprises a flexible material, e.g., silicone, such that during the advancement of system  200 , cross-bar element  214  is typically aligned approximately in parallel with the straightened core catheter  202 . Once the straightening rod is removed from within catheter  202 , cross-bar element  214  is allowed to assume its configuration as shown. 
     Typically, cross-bar element  214  is shaped so as to, define a lumen therethrough, and comprises an elastic coupling band  218  that passes through the lumen. Two portions of coupling band  218  protrude from cross-bar element  214 , and are coupled to portion  208  of catheter  202  at two respective points. For some applications, band  218  is generally rigid in central areas thereof, while elastic near the ends thereof. Alternatively, cross-bar element  214  does not comprise coupling band  218 , and is coupled directly to portion  208  of catheter  202 . Further alternatively, exactly one end of cross-bar element  214  is coupled directly to portion  208 . 
     Typically, cross-bar element  214  functions to prevent compression of portions  208  and  210  of catheter  202 , while coupling band  218  functions to inhibit the straightening of portions  208  and  210  of catheter  202  (e.g., in response to peristaltic motion of the stomach) by pulling the opposite portions of portion  208  into a curved configuration. It is to be noted that although coupling band  218  is configured to inhibit straightening of portions  208  and  210  of catheter  202  in response to peristaltic motion of the stomach, coupling band  218  is elastic enough such that catheter  202  may be straightened in response to a pulling force applied thereto (e.g., by an operating physician). 
     For applications in which catheter  202  comprises exactly two cross-bar elements  214  (configuration not shown), the two elements are typically approximately perpendicular to one another when catheter  202  is in its relaxed position. 
     Cross-bar element  214 , together with band  218 , helps maintain the shape of the catheter  202 , so that portions  208  and  210  of catheter  202  are not compressed and straightened, respectively, as they interfere with gastric emptying, and so that catheter  202  does not pass into the duodenum of the subject. For some applications, cross-bar element  214  comprises a rigid material, such as metal (e.g., stainless steel), or nylon, Pebax® (Arkema), Teflon® (DuPont), or another similar material, with or without metal inserts, while for other applications element  214  comprises a more flexible, but still somewhat rigid, material, such as plastic or silicone. For embodiments in which element  214  comprises the rigid material, the rigid material is configured to prevent crushing or compression of the pre-selected bent configuration of catheter  202 . 
     It is to be noted that portion  210  of catheter  202  may also be coupled to one or more cross-bar elements  214 . Techniques for use with cross-bar elements  214  described herein may be used in combination with techniques for use of the cross-bar elements as described in PCT Patent Application PCT/IL2007/000398 to Brooks, entitled “Floating gastrointestinal anchor,” which is incorporated herein by reference. 
     It is to be noted that techniques for non-endoscopically accessing intrabody apparatus  80  described herein may be used in combination with system  200  described herein with reference to  FIG. 15 . 
     It is to be further noted that embodiments described herein may be practiced in combination with other embodiments described herein. For example, projections  66 , as described hereinabove with reference to  FIG. 3 , may be coupled at a proximal end of core catheter  40  (described in  FIGS. 2A-2B ,  4 A- 5 C,  7 A- 14 ) and catheter  202  shown in  FIG. 15 . Projections  66  may also be coupled to appendage retraction tube  132  (described hereinabove with reference to  FIGS. 5A-5C ), in order to facilitate extraction of appendage retraction tube  132  from within core catheter  40  and out of the body of the subject. Additionally, crown  175 , described hereinabove with reference to  FIG. 13 , may be coupled at a proximal end of core catheter  40  (described with reference to  FIGS. 2A-2B ,  4 A- 5 C,  7 A- 14 ), and/or to a proximal end of appendage retraction tube  132  (described hereinabove with reference to  FIGS. 5A-5C ). In embodiments in which crown  175  is coupled to either core catheter  40  and/or appendage retraction tube  132 , projections  66  may be coupled to crown  175 . 
     It is to be further noted that cap  174  (described hereinabove with reference to  FIG. 13 ) may be coupled to proximal ends of core catheter  40  (described hereinabove with reference to  FIGS. 2A-4B ,  7 A- 12 , and  14 ), and/or to appendage retraction tube  132  (described hereinabove with reference to  FIGS. 5A-5C ). 
     It is to be noted that anchor shapes shown in the various figures are by way of illustration and not limitation. For example, limbs  58 ,  102  and  160  may function not only as “Y” shaped anchors, but in other embodiments as “T” shaped anchors or as anchors having other shapes. 
     Typically, non-endoscopic embodiments described hereinabove are performed without visualizing the interior of the gastrointestinal tract. For some applications, however, the techniques described herein are performed endoscopically, e.g., if deemed appropriate for a given patient. 
     The scope of the present invention includes the use of the method for non-endoscopic insertion described hereinabove for inserting devices other than a gastric balloon into the stomach of the subject. For example, intrabody apparatus  80  may be configured to reside entirely out of the gastrointestinal tract of the subject. Alternatively, a portion of intrabody apparatus  80  may be configured to reside within the gastrointestinal tract of the subject. 
     It is to be noted that systems  20  and  200  may be configured for insertion and removal of a device other than the particular medical intrabody apparatus described herein. 
     The scope of the present invention includes embodiments described in one or more of the following: 
     U.S. Provisional Patent Application 60/927,101 to Brooks, entitled, “Non-endoscopic insertion and removal of a device,” filed Apr. 30, 2007 
     PCT Patent Application PCT/IL2007/000398 to Brooks, entitled “Floating gastrointestinal anchor,” filed Mar. 28, 2007; 
     U.S. Provisional Patent Application 60/850,071 to Brooks, filed Oct. 6, 2006, entitled, “Radiopaque marking to detect balloon deflation”; 
     U.S. Provisional Patent Application 60/815,624 to Brooks, filed Jun. 21, 2006, entitled, “Floating gastrointestinal anchor”; 
     U.S. Provisional Patent Application 60/787,124 to Brooks, filed Mar. 28, 2006, entitled, “Floating gastrointestinal anchor”; 
     PCT Patent Application PCT/IL05/001381 to Brooks, filed Dec. 27, 2005, entitled Floating gastrointestinal anchor.” 
     All of these applications are incorporated herein by reference. Techniques described herein can be practiced in combination with techniques described in one or more of these applications. 
     For some applications, techniques described herein are practiced in combination with techniques described in one or more of the references cited in the Background section and Cross-References section of the present patent application. All references cited herein, including patents, patent applications, and articles, are incorporated herein by reference. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.