PATENT ABSTRACT
A method for using a trocar assembly for transstomal endoscopic procedures. The method comprises the steps of providing a trocar comprising a handle and a tubular cannula extending from the handle, the handle defining an operating channel continuous with a lumen of the cannula, wherein an annular balloon is disposed on the outside of the cannula; inserting the distal end of the trocar cannula into the stoma and advancing the trocar until the annular balloon is inside the stoma; and inflating the annular balloon to sealingly engage the opening of the stoma.

PATENT DESCRIPTION
[0001]     This is a non-provisional application claiming the priority of provisional application Ser. No. 60/597,229, filed on Nov. 17, 2005, which is fully incorporated herein by reference. 
     
    
     FIELD  
       [0002]     The present invention relates generally to endoscopic tools and more particularly, but without limitation, to endoscopic trocar assemblies, and methods of using trocar assemblies for transstomal endoscopic procedures.  
       BACKGROUND  
       [0003]     Mechanical trocars typically include a cannula defining a working channel and a housing, which encloses valves that function to inhibit the escape of gas or fluids. Typically, the cannula of the trocar is adapted to be positioned across the abdominal wall of a patient using an obturator, which is initially inserted into the working channel and then removed once an entry site through the abdominal wall has been made and the cannula is in place. Various elongated instruments can be inserted through the working channel of the trocar to reach and perform operative functions at a site within the abdomen.  
         [0004]     In most patients, the obturator creates an entry site into the body cavity through with the cannula of the trocar is inserted. In patients who have had a prior colostomy or iliostomy, however, the stoma provides a pre-existing entry site into the body for examination and/or treatment of intestinal or urological structures.  
         [0005]     A stoma is an opening to the intestine on the abdominal wall, usually created by a surgeon. A stoma is necessary when parts of the normal intestine must be bypassed, for example when bowel surgery has removed important lengths of the intestine. There are several types of stoma, which take their name from the part of the intestine that forms the opening. These include gastrostomy, an opening from the skin directly into the stomach; jejunostomy, an opening from the first part of the small bowel, ileostomy, an opening from the small bowel, and colostomy, an opening from the large bowel. Another type of stoma, called a urostomy, is an artificial connection between the urinary tract (the kidneys, bladder and tubes that connect them) and the abdominal wall, sometimes referred to as a ‘urinary conduit’.  
         [0006]     Transstomal endoscopic procedures may play an important role in the management of patients who have undergone procedures such as colonostomies. For example, at least one study has shown that transstomal endoscopic exploration in rectal cancer patients who have undergone a colonoscopy is a safe and effective tool in monitoring for recurrence of cancer, as rectal cancer patients are at high risk for metachronous large-bowel primaries. See, Zilli, L. Pietroiust, M. and Bertario, L. (1987) Dis. Colon Rectum 30(9): 687-691. However, endoscopic procedures on intestinal structures in patients with colostomies and on urological structures in patients with iliostomies are problematic because there is no sphincter in the stoma to contain the air or fluid in the colon or conduit typically introduced during endoscopic procedures. In addition, the trocar sleeve on the conventional trocar assembly is too long for effective use in a stoma. The present invention is directed to an apparatus and a method of conducting endoscopic procedures through a stoma, which address these problems.  
       SUMMARY  
       [0007]     The present invention comprises a trocar assembly for transstomal endoscopic procedures and a method for using the same. The assembly comprises a handle and a tubular trocar sleeve extending from the handle. The handle defines an operating channel continuous with the lumen of the sleeve. An annular balloon is disposed on the outside of the sleeve. Also included is an inflation system to connect the balloon with a source of fluid. The trocar may also include a seal near the opening to the operating channel in the handle for sealing the opening during use of the trocar.  
         [0008]     The present invention also comprises a method for inserting a cannula through a stoma in the wall of a body cavity for use in transstomal endoscopy, comprising the steps of: providing a trocar comprising a handle and a tubular cannula extending from the handle, the handle defining an operating channel continuous with a lumen of the cannula, wherein an annular balloon is disposed on the outside of the cannula; inserting the distal end of the trocar cannula into the stoma and advancing the trocar until the annular balloon is inside the stoma; and inflating the annular balloon to sealingly engage the opening of the stoma.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a side elevational view of a trocar assembly constructed in accordance with the present invention. The balloon on the trocar sleeve is deflated. Only the tip of the introducer is shown.  
         [0010]      FIG. 2  is a side elevational view of the trocar assembly of  FIG. 1  with the balloon inflated.  
         [0011]      FIG. 3  is a perspective view of the trocar assembly of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0012]     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices and materials are now described.  
         [0013]     All publications mentioned herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the structures and/or methodologies that are described in the publications which might be used in connection with the presently described invention. The publications discussed above and throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention.  
         [0014]     The present invention is directed to a trocar assembly for transstomal endoscopic procedures. A preferred embodiment of the inventive trocar assembly is shown in  FIGS. 1-3 , to which reference now is made.  
         [0015]     The trocar assembly is designated generally by the reference numeral  10 . The assembly  10  comprises a head or handle  12  by which the assembly  10  is controlled for atraumatic insertion of the trocar into the stoma. An operating channel  14  is provided for insertion of a colonoscope, cytoscope or other tools into the trocar. The opening into the operating channel  14  preferably includes a valve or seal, indicated at  16 , for forming an air seal with the tool being inserted into the trocar.  
         [0016]     A tubular cannula or sleeve  18  extends from the handle  12 . The lumen  20  of the sleeve communicates with the operating channel  14  in the handle  12 . The size and length of the sleeve  18  may vary. A preferred sleeve diameter for trocars used in patients having colostomies or iliostomies is a diameter of 19 mm, as this size will accommodate the easy introduction of most colonoscopes and cytoscopes. As one skilled in the art will readily appreciate, however, the diameter may be larger or smaller, depending on the type and size of the patient&#39;s stoma and the instruments to be used during the procedure.  
         [0017]     The sleeve  18  is shorter than the sleeve on a conventional endoscopic trocar. In one embodiment, the sleeve of the present trocar is about two to three (3) inches in length, preferably about three inches. Again, however, this length will vary depending on the type and size of the stoma, the patient&#39;s anatomy, the particular procedure being undertaken, and the like.  
         [0018]     The introducer used in the assembly  10  is of conventional design and, therefore, is not shown or described in detail. However, as will be understood from the drawings, the size of the introducer is adjusted to conform to the sleeve  18 . In addition, the end of the introducer  21  preferably is blunted to minimize the risk of trauma to the tissues during insertion. Unlike obturators used in conventional trocars, the end of the introducer does not provide a cutting function to provide an entry site through the body wall but instead serves to open the stoma to facilitate passage of the trocar sleeve or cannula through the stoma. The introducer&#39;s smooth or blunt tip  21  helps prevent damage to the stoma or to the intestine during insertion of the trocar.  
         [0019]     An annular balloon  22  is disposed on the sleeve  18 . The balloon may be adhesively affixed to the sleeve and/or disposed between a pair of brackets  23  that prevent movement of the balloon along the trocar sleeve. The balloon  22  is sized and positioned to sealingly engage the stoma when the sleeve is inserted into the stoma and the balloon is inflated.  
         [0020]     An inflation system  24  is included for connecting the balloon  22  to a source of fluid or gas, such as water or air. The inflation system  24  includes a valve  26  that may be mounted on the handle  12 . The valve  24  includes a port  28  connected by a passageway  30  to the balloon  22 . Preferably, the port  28  is adapted to receive the tip of a syringe (not shown). In this way, inflation and deflation of the balloon  22  is accomplished simply by injecting and withdrawing air (or other gas, or fluid) with a syringe.  
         [0021]     Given the above-described structure, the use and operation of the trocar assembly of the present invention should be readily apparent to those of skill in this art. Briefly, an introducer is inserted into the operating channel of the trocar and through the lumen so that the blunt tip of the introducer protrudes slightly from the rounded distal end of the trocar sleeve. The sleeve  18  is inserted a distance into the colon or ileal conduit through the stoma and the introducer is removed. Preferably, the sleeve is inserted into the colon or conduit until the deflated balloon is just inside the stoma opening, inside the lumen of the colon or conduit. Next, using a syringe, air or water is injected into the balloon  22  so that the balloon engages the inner wall of the colon or conduit to seal the opening of the stoma.  
         [0022]     With the trocar sleeve  18  positioned, the colonoscope or cytoscope or other tool is inserted into the opening into the operating channel  14  in the handle  12 . Once the tool is inserted a sufficient distance, air, water or another suitable fluid is introduced into the conduit or colon. The seal  16  at the opening of the operating channel prevents air or fluids from escaping through the trocar  10 , and the inflated balloon forms a seal between the intestinal wall or stoma and the trocar sleeve  18 .  
         [0023]     Although the present invention has been described in certain specific aspects, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that the present invention may be practiced otherwise than specifically described, including various changes in the size, shape and materials, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive. Also, all the examples provided throughout the entire description should be considered in all respects as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the following claims rather than by the foregoing description. All changes, modifications, and variations coming within the meaning and range of equivalency of the claims are to be considered within their scope.