Abstract:
A method of controlling obesity by physically narrowing the lumen of the pylorus One embodiment includes injection of a bio-compatible bulking or stiffening material into the pyloric sphincter area of the stomach. The injection of this material bulks the pyloric sphincter, narrowing the lumen, retarding stomach emptying and producing a feeling of satiation in the patient. The method may be practiced or supplemented by cauterization of the pyloric sphincter or by suturing the sphincter to narrow the same and may be augmented by inducing flacid paralysis of the stomach by injecting botulinum toxin into the muscle tissue of the antrum or fundus of the stomach.

Description:
The present application is a continuation-in-part of U.S. patent application Ser. No. 10/343,668, filed Aug. 13, 2003, which is a U.S. National Phase Application of International Application No. PCT/US01/24971, filed Aug. 9, 2001, which claims priority of U.S. Provisional Application No. 60/224,324, filed Aug. 11, 2000. 
    
    
     FIELD OF INVENTION 
     The present invention relates to a method for controlling obesity by narrowing the pyloric sphincter area of the stomach. The narrowing of the pyloric sphincter retards stomach emptying and produces a feeling of satiation in the patient. 
     BACKGROUND OF THE INVENTION 
     Obesity is one of the major causes of heart disease, lipid abnormalities, hypertension and osteoarthritis. Treatment of obesity has the potential to lower the risk of all of these diseases as well as improve the condition of patients who already suffer from such illnesses. In addition, it is well known that a large percentage of Americans and Europeans are considered to be obese based on height and weight ratios issued by the World Health Organization (WHO). These numbers in conjunction with the dangerous diseases affiliated with or caused by obesity indicate that there is a substantial need for effective treatment. 
     Current weight reduction programs usually include administration of systemic medications, which suppress the appetite or reduce the fat and/or sugar uptake of the digestive tract. However, systemic medications often display side effects, some of which may be severe. Dietary changes that reduce caloric intake are also prescribed for the treatment of obesity, but such treatment requires rigorous compliance by the patient for effectiveness and is often ineffective as a result of non-compliance. In addition, surgery, which bypasses a portion of the stomach and/or the small intestine, is also used in the treatment of obesity. Surgical methods, however, are highly invasive and subject a patient to all the possible risks involved with major surgery including infection. 
     Safe and effective treatment is a long felt need in the treatment of obesity. Because of complications and/or ineffectiveness associated with current treatments a minimally invasive, effective treatment is preferred and is provided by the method of this invention. 
     SUMMARY OF THE INVENTION 
     The present invention provides a minimally invasive method for controlling obesity comprising narrowing the pyloric sphincter of the stomach sufficiently to cause the lumen of the pylorus to narrow and slow gastric emptying. The method is performed endoscopically, that is, through an use of an endoscope inserted into the lumen of the stomach itself. The method may be practiced by endoscopically injecting a bulking or stiffening material into the pyloric area of the stomach, cauterizing the pylorus, suturing the pyloric sphincter, or a combination of these techniques. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is a method of treating obesity in which gastric emptying is slowed by narrowing the pyloric sphincter or pylorus, thus narrowing the lumen of the pylorus through which food must pass from the stomach into the small intestine. The invention comprises narrowing of the pyloric sphincter or pyloric area of the stomach sufficiently to narrow the lumen of the pylorus and slow gastric emptying. By narrowing the pyloric opening of the stomach, the stomach will fill more quickly and empty more slowly as a patient eats. The clinical effect of this treatment will be to increase the time the patient feels satiated after eating, therefore decreasing the need and desire to eat and reducing the caloric intake of the patient. 
     In accordance with the present invention, the pylorus can be caused to narrow by several means, used either alone or in combination. These means are all minimally invasive in that they are performed through an endoscope inserted through the upper digestive tract into the lumen of the stomach. 
     One embodiment of the invention includes the injection of a bio-compatible bulking or stiffening material into the mucosal, submucosal or muscular area around the pylorus. Such an injection can be accomplished by a two step process wherein an endoscopy is performed to locate the pylorus and a needle is placed through the biopsy channel of the endoscope in order to inject the bulking material. Such an injection will increase the bulk and/or stiffness of the pylorus and thus narrow the gastric outlet from the stomach to the start of the small intestine. 
     The bio-compatible bulking materials suitable for the present invention include but are not limited to collagen, fibrin and elastin as well as other naturally occurring and synthetically derived bio-compatible polymers. Certain polymers such as collagen, fibrin glue, and plastic polymers have been demonstrated to be well tolerated when injected into lumen in humans. In addition, such materials are commercially available. For instance, collagen may be purchased from FribroGen, Inc., Cohesion Technologies, Inc., Hydromer, Inc., and Bard, Inc., and fibrin glue may be purchased from Abbott Laboratories, Inc. Suitable plastic polymers include Enteryx™, a flexible liquid polymer composition which may be purchased from Enteric Medical Technologies. Various other similar products for injection include, but are not limited to, Contigen® (Contigen is a registered trademark of the Collagen Corporation and is a protein composition for medical implants for relief of urinary tract disorders), Zyderm® (Zyderm is a registered trademark of the Collagen Corporation and is a protein composition for dermal implantation), Zyplast® (Zyplast is a registered trademark of the Collagen Corporation and is a collagen implant used for soft tissue augmentation), rh collagen, Dermalogen® (Dermalogen is a registered trademark of Collagenesis, Inc. and is injectable human tissue for treating wrinkles and scars), Autologen® (Autologen is a registered trademark of Autogenesis Technologies, Inc. and is processed collagen for implantation), and autologous fat. 
     Collagen for use in the present invention can be from several sources including porcine, bovine, or human. It can be either fibrillar or nonfibrillar. Collagen can be administered in aqueous solution form or in the denatured state as gelatin. In addition, it can be administered in either a crosslinked or a non-crosslinked form. 
     Although collagen is the most commonly used bulking material, other materials can be used and may have equal or better efficacy. For instance, Teflon paste, synthetic polymeric hydrogels, glycoaminoglycans, proteoglycans, silicone microimplants, Durasphere® (Durasphere is a registered trademark of Advanced UroScience, Inc. and consists of biocompatible, implantable microspheres for local tissue augmentation), Enteryx™ from Enteric Medical Technologies, and microbeads suspended in biological fluid lubricants such as dextran have been demonstrated to be tolerated when injected into human tissue. 
     The amount of bio-compatible bulking material injected into the pyloric area of the stomach will be dependent of a variety of factors. For instance, the size of the individual, the severity of the individual&#39;s obesity, and the shape and distension of the pylorus will all be determinative in calculating the amount of bulking material injected. It is estimated that the opening of the pyloric sphincter can be reduced at least 10% and up to 90% by the instant invention. 
     The injection of collagen or fibrin glue into the pylorus is expected to last for 3 to 12 months. If the body absorbs the bio-compatible bulking material, it can be re-injected by a repeat of the method described. However, a number of plastic polymer injectables may be permanent. If the narrowing of the pylorus is found to be too great, the opening can be increased by the use of a balloon, which can be inserted into the pylorus and inflated to increase the opening. This flexibility in adjusting the pyloric opening to accommodate specific patent requirements provides a unique advantage over present surgical procedures. 
     While the injection of the bio-compatible bulking material into the pyloric area will control obesity, the invention may encompass additional procedures for narrowing the pylorus. For instance, the pyloric area can also be narrowed by intentionally scarring the pyloric area with either a laser or a thermal device, such as a radio frequency probe, a monopolar electrocautery, or a bipolar electrocautery. In such an embodiment of the invention, a laser or heating device could be placed through the biopsy channel of the endoscope and used to cauterize an area of the pylorus. Such an embodiment may be used as an adjunct in addition to injection of a bio-compatible bulking material or may itself be used to narrow the lumen of the pylorus and thus narrow the gastric outlet from the stomach to the mall intestine. Thus, in another aspect the invention includes a method of treating obesity comprising cauterizing the pyloric area of the stomach sufficiently to cause the lumen of pylorus to narrow and slow gastric emptying. 
     In another embodiment of the invention, a sewing device can be placed through the biopsy channel of the endoscope or attached to an endoscope and used to sew the pylorus and narrow the opening of the pyloric sphincter. This may be accomplished by placing sutures anchored on opposing sides of the pylorus, in the pyloric muscle, mucosa or sub-mucosa, then drawing the sides together and securing the sutures with a desired degree of tension or at a desired length, suitably with a movable tensioning/retaining member This method has the advantage of providing excellent control over the degree of narrowing of the pyloric outlet of the stomach, enables the practitioner to adjust the sutures as needed to accommodate individual needs and variations, and may be used alone or in combination with the injection of a bio-compatible bulking material. Thus, this aspect of the invention includes a method of treating obesity comprising suturing the pyloric area of the stomach sufficiently to cause the lumen of pylorus to narrow and slow gastric emptying. 
     In yet another aspect of the invention, gastric emptying can be further delayed by inducing a flaccid paralysis of the of the stomach. Botulinum toxin will cause a paralysis of the stomach if it is strategically injected into either the muscles of the fundus or the antrum of the stomach. Paralyzing the stomach in this way will prolong satiety by further delaying gastric emptying. The effects of botulinum toxin is expected to last for a period of 9 to 18 months. This aspect of the invention may be utilized in combination with any of the above identified embodiments as desired.