Abstract:
A device for inducing satiety including an elongated device for insertion through a natural orifice and into a stomach of the patient. The distal end of the device includes a means for occupying space between the submucosal and muscularis layers adjacent a pyloric sphincter. The means has a collapsed state for delivery to a target site and an expanded state for implantation thereof.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to obesity surgery. 
       BACKGROUND OF THE INVENTION 
       [0002]    Obesity is a medical condition affecting more than 30% of the population in the United States. Obesity affects an individual&#39;s personal quality of life and contributes significantly to morbidity and mortality. Obese patients, i.e. individuals having a body mass index (“BMI”) greater than 30, often have a high risk of associated health problems (e.g., diabetes, hypertension, and respiratory insufficiency), including early death. With this in mind, and as those skilled in the art will certainly appreciate, the monetary and physical costs associated with obesity are substantial. In fact, it is estimated the costs relating to obesity are in excess of 100 billion dollars in the United States alone. Studies have shown that conservative treatment with diet and exercise alone may be ineffective for reducing excess body weight in many patients. 
         [0003]    Bariatrics is the branch of medicine that deals with the control and treatment of obesity. A variety of surgical procedures have been developed within the bariatrics field to treat obesity. The most common currently performed procedure is the Roux-en-Y gastric bypass (RYGB). This procedure is highly complex and is commonly utilized to treat people exhibiting morbid obesity. In a RYGB procedure a small stomach pouch is separated from the remainder of the gastric cavity and attached to a resectioned portion of the small intestine. This resectioned portion of the small intestine is connected between the “smaller” gastric cavity and a distal section of small intestine allowing the passage of food therebetween. The conventional RYGB procedure requires a great deal of operative time. Because of the degree of invasiveness, post-operative recovery can be quite lengthy and painful. Still more than 100,000 RYGB procedures are performed annually in the United States alone, costing significant health care dollars. 
         [0004]    In view of the highly invasive nature of the RYGB procedure, other less invasive procedures have been developed. These procedures include gastric banding, which constricts the stomach to form an hourglass shape. This procedure restricts the amount of food that passes from one section of the stomach to the next, thereby inducing a feeling of satiety. A band is placed around the stomach near the junction of the stomach and esophagus. The small upper stomach pouch is filled quickly, and slowly empties through the narrow outlet to produce the feeling of satiety. In addition to surgical complications, patients undergoing a gastric banding procedure may suffer from esophageal injury, spleen injury, band slippage, reservoir deflation/leak, and persistent vomiting. Other forms of bariatric surgery that have been developed to treat obesity include Fobi pouch, bilio-pancreatic diversion and gastroplasty or “stomach stapling”. 
         [0005]    Morbid obesity is defined as being greater than 100 pounds over one&#39;s ideal body weight. For individuals in this category, RYGB, gastric banding or another of the more complex procedures may be the recommended course of treatment due to the significant health problems and mortality risks facing the individual. However, there is a growing segment of the population in the United States and elsewhere who are overweight without being considered morbidly obese. These persons may be 20-30 pounds overweight and want to lose the weight, but have not been able to succeed through diet and exercise alone. For these individuals, the risks associated with the RYGB or other complex procedures often outweigh the potential health benefits and costs. Accordingly, treatment options should involve a less invasive, lower cost solution for weight loss. 
         [0006]    With the foregoing in mind, it is desirable to have a surgical weight loss procedure that is inexpensive, with few potential complications, and that provides patients with a weight loss benefit while buying time for the lifestyle changes necessary to maintain the weight loss. Further, it is desirable that the procedure be minimally invasive to the patient, allowing for a quick recovery and less scaring. The present invention provides such a procedure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a needle assembly penetrating the mucosal layer of the gastric cavity; 
           [0008]      FIG. 2  is a perspective view similar to  FIG. 1 , showing a fluid being infused between the mucosal and muscularis layers of the gastric wall; 
           [0009]      FIG. 3  is a perspective view similar to  FIG. 2 , showing a fluid pocket formed within the gastric wall; 
           [0010]      FIG. 4  is a perspective view of a first embodiment of an implantable device; 
           [0011]      FIG. 5  is a schematic view of a needle tip penetrating the gastric wall; 
           [0012]      FIG. 6  is a schematic view of a stent device being ejected through the tip of a needle assembly; 
           [0013]      FIG. 7  is a schematic view showing the stent device fully implanted under the mucosal layer of the gastric wall; 
           [0014]      FIG. 8  is a schematic view showing the mucosal and muscularis layers deformed by the implanted stent; 
           [0015]      FIG. 9  is a diagrammatic view of a gastric cavity containing a ring of implanted devices; 
           [0016]      FIG. 10  is a perspective view of a spherical stent being deployed from a needle assembly; 
           [0017]      FIG. 11  is a perspective view of a gastric cavity, partially cut away to show a stent device implanted in the anterior antrum wall; 
           [0018]      FIG. 12  is a perspective view showing a second embodiment for an implantable device being implanted into the gastric wall; 
           [0019]      FIG. 13  is a perspective view showing the second implant embodiment being inflated to deform the cavity wall; 
           [0020]      FIG. 14  is a perspective view showing a third embodiment for an implantable device being introduced into a gastric wall; 
           [0021]      FIG. 15  is a perspective view of the third implant device embodiment, showing the device encircling within the gastric wall; 
           [0022]      FIG. 16  is a perspective view similar to  FIG. 15 , showing an additional length of the wire bunching up within the gastric wall; 
           [0023]      FIG. 17  is a perspective view of a gastric cavity, showing a fourth embodiment for an implantable device being implanted into the antrum cavity wall; 
           [0024]      FIGS. 18A-18C  show expansion of the fourth implantable device during release from a needle assembly; 
           [0025]      FIGS. 19A-19C  show expansion of the fourth implantable device beneath the mucosal layer of the gastric wall; and 
           [0026]      FIG. 20  shows a plurality of the fourth embodiment devices implanted about the periphery of the antrum. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Smooth muscle tumors of the stomach, also known as “stromal cell tumors”, typically originate in the smooth musculature of the gastric wall. Through clinical studies, it has been determined that when stromal cell tumors occur in the antrum and, particularly, in the anterior wall of the antrum, the tumors interrupt the normal contractions of both the circular and longitudinal bands of muscles within the gastric cavity wall. This interruption in muscular contractions slows stomach emptying, resulting in a loss of appetite. 
         [0028]    The present invention provides a method for treating obesity which simulates the effects of a stomach cell tumor in order to disrupt and slow gastric emptying. In the present invention, one or more devices are implanted between the mucosal and muscularis layers of the gastric cavity wall to disrupt the normal gastro-muscular movements. The devices may be implanted transesophageally in a minimally invasive procedure using a conventional endoscope with an optical viewing device. Alternatively, the devices may be implanted exogastrically in a minimally invasive laparoscopic procedure. The clinical effect of the implants will be to increase the time the patient feels satiated after eating, thereby decreasing the need and desire to eat, and reducing the overall caloric intake of the patient. 
         [0029]    Methods of implanting different device embodiments will now be described using a transesophageal procedure. With an endoscope  20  inserted transorally into the stomach cavity, a needle assembly is passed through the endoscope to the intended location of the implant. To produce optimum results, the implant is placed in the antrum portion of the stomach. Using the needle assembly  22 , as shown in  FIG. 1 , the mucosal layer  24  is penetrated with the needle tip at the intended implant location. With the needle tip  26  between the mucosal and muscularis layers, a fluid is injected through the needle, as shown in  FIG. 2 , to separate the cavity wall layers and form a fluid pocket or bleb  30  therebetween. Following the infusion of fluid, needle tip  26  is withdrawn from the mucosa  24 , as shown in  FIG. 3 . The needle assembly is then removed from endoscope  20  and replaced with a second needle assembly. This second needle assembly includes an implant device loaded within a needle lumen. 
         [0030]      FIG. 4  shows a first embodiment for an implantable device of the present invention. In this embodiment, the device comprises an expandable stent  32  composed of Nitinol, or another type of self-expanding, biocompatible material. In this embodiment, stent  32  is passed through a needle lumen in a compressed form, and then expanded into a spherical shape once implanted within the gastric wall. As shown in  FIG. 5 , to implant stent  32 , second needle assembly  34  is passed through endoscope  20 . The sharpened tip  36  of the needle assembly is maneuvered into contact with the mucosal layer  24  of the stomach at the location of bleb  30 . Tip  36  of the needle pierces mucosal layer  24 , so as to position the distal opening of the needle lumen inside of bleb  30 . With needle tip  36  between mucosal layer  24  and muscularis layer  40 , stent  32  is passed out of the needle lumen and into the pocket formed between the cavity layers. As stent  32  exits needle  34 , the stent expands into a ball-like shape. The expanded stent  32  deforms the surrounding mucosal and muscularis layers, as shown in  FIG. 6 . 
         [0031]    After stent  32  is released, needle tip  36  is removed from the cavity wall, as shown in  FIG. 7 , and needle assembly  34  retracted back through endoscope  20 . 
         [0032]    The opening in mucosal layer  24  then closes around stent  32 , as shown in  FIG. 8 . This process of forming a bleb and inserting a stent may be repeated at one or more additional locations in the gastric cavity wall to implant additional stents. The additional stents may also be placed into the anterior wall of the antrum. Alternatively, the additional stents may be placed in a ring about the anterior and posterior walls of the antrum, as shown in  FIG. 9 .  FIGS. 10 and 11  provide additional views of an implanted stent  32 , showing the various layers within the gastric cavity wall, and the location of the stent between the mucosal and smooth muscle layers  24 ,  40 . The mesh-type structure of stent  32  promotes tissue ingrowth after implantation, inhibiting migration of the device within or out of the cavity wall. 
         [0033]      FIG. 12  shows an alternative embodiment for an implantable device, in which the device comprises an inflatable balloon  42 . Balloon  42  may be comprised of any bio-compatible material. As shown in  FIG. 12 , balloon  42  may be inserted via needle assembly  34  into the bleb  30  formed between the mucosal and muscularis layers. A catheter  44  extends through the needle lumen and through an opening in balloon  42 . After balloon  42  is inserted into bleb  30 , the balloon may be inflated via a fluid passed through catheter  44 , as shown in  FIG. 13 . After balloon  42  is inflated, catheter  44  is removed from the balloon, and the catheter and needle assembly are retracted back through endoscope  20 . Additional balloons  42  may be implanted into the anterior antrum wall, or into other locations about the antrum, to achieve the desired effect on the gastric muscular contractions. 
         [0034]      FIG. 14  shows a third embodiment for an implantable device in which the device comprises a length of thin, flexible material such as, for example, a biocompatible metal wire  50 . As in the embodiments above, wire  50  may be inserted via needle assembly  34  into the bleb  30  formed between the mucosal and muscularis layers. The tip of needle  34  penetrates the mucosal layer to provide an opening for injecting wire  50  into bleb  30 . As the length of wire  50  is passed into the gastric wall, as shown in  FIG. 15 , the wire is encircled about within bleb  30  to create a bunching effect, and thereby form a three-dimensional implant of increased spatial size. The disoriented arrangement of the encircled wire  50 , shown in  FIG. 16 , inhibits migration of the wire within the gastric layers to maintain the position of the implant. Wire  50  may be formed of Nitinol, titanium, or another type of semi-flexible, biocompatible material. As in the previous embodiments, a plurality of wire lengths  50  may be implanted at various locations within the antrum to achieve the desired effect on the gastric cavity. 
         [0035]      FIG. 17  shows a fourth embodiment for an implantable device in which the device comprises a molly bolt  54 . Bolt  54  has a compressed shape, shown in  FIGS. 18A and 19A , during entry through needle assembly  34  and mucosal layer  24 . As bolt  54  is released into bleb  30 , the sides of the bolt expand outward, as shown in  FIGS. 18B and 19B . Once bolt  54  is fully released from needle assembly  34 , the bolt assumes a maximum spatial capacity, as shown in  FIGS. 18C and 19C . The expanded size of bolt  54  within bleb  30  allows the bolt to deform the surrounding areas of the cavity wall. A ring of bolts  54  may be formed around the antrum, as shown in  FIG. 20 , to produce deformation of the gastric layers about the perimeter of the cavity. 
         [0036]    As described above, the implant devices of the present invention can vary as to shape and composition, with the goal that the implant interferes with the contraction of the longitudinal and circular gastric muscles during digestion. The devices&#39; interference with the normal muscle contractions increases gastric emptying times and, thus, prolongs the feeling of satiety. Each of the implants described above is formed of a bio-compatible material that resists migration within the stomach wall. Any number of the devices may be implanted during a procedure, depending upon the desired degree of muscular disruption. 
         [0037]    The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.