Abstract:
Method for implanting a percutaneous endoscopic jejunostomy tube in a patient and access needle for use in the method. In one embodiment, the method comprises the steps of (a) providing an access needle wherein the distal end of the stylet extends distally for an appreciable distance beyond the distal end of the cannula; (b) inserting the stylet, but not the cannula, into the jejunum; (c) grabbing the stylet with an endoscopically-positioned snare; (d) anchoring the jejunum against the abdominal wall using the snared stylet; (e) loosening the snare slightly while advancing the cannula into the jejunum and into the loosened snare; (f) tightening the snare around the cannula; (g) removing the stylet from the cannula; (h) inserting a guide wire or suture through the cannula into the jejunum; and (i) proceeding in the conventional fashion to implant a PEJ tube into the patient using the guide wire or suture.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional of U.S. application Ser. No. 10/300,702, filed Nov. 20, 2002, now abandoned which claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Serial No. 60/335,681, filed Nov. 21, 2001, and of U.S. Provisional Patent Application Ser. No. 60/418,990, filed Oct. 15, 2002, all of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to percutaneous endoscopic gastrostomy (PEG) tubes and percutaneous endoscopic jejunostomy (PEJ) tubes and methods for their implantation in a patient and relates more particularly to a novel method for implanting a PEG tube or a PEJ tube in a patient and to a novel access needle for use in said method. 
     Certain patients are unable to take food and/or medications transorally due to an inability to swallow. Such an inability to swallow may be due to a variety of reasons, such as esophageal cancer, neurological impairment and the like. Although the intravenous administration of food and/or medications to such patients may be a viable short-term approach, it is not well-suited for the long term. Accordingly, the most common approach to the long-term feeding of such patients involves gastrostomy, i.e., the creation of a feeding tract or stoma between the stomach and the upper abdominal wall. Feeding is then typically performed by administering food through a catheter or feeding tube that has been inserted into the feeding tract, with the distal end of the feeding tube extending into the stomach and being retained therein by an internal anchor or bolster and the proximal end of the feeding tube extending through the abdominal wall. 
     Although gastrostomies were first performed surgically, most gastrostomies are now performed using percutaneous endoscopy and result in the implantation of a gastrostomy feeding tube assembly (also referred to as a percutaneous endoscopic gastrostomy (PEG) device) in the patient. Two of the more common techniques for implanting a PEG device in a patient are “the push method” (also known as “the Sacks-Vine method”) and “the pull method” (also known as “the Gauderer-Ponsky method”). Information regarding the foregoing two methods may be found in the following patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,391,159, inventors Hirsch et al., which issued Feb. 21, 1995; U.S. Pat. No. 5,167,627, inventors Clegg et al., which issued Dec. 1, 1992; U.S. Pat. No. 5,112,310, inventor Grobe, which issued May 12, 1992; U.S. Pat. No. 4,900,306, inventors Quinn et al., which issued Feb. 13, 1990; and U.S. Pat. No. 4,861,334, inventor Nawaz, which issued Aug. 29, 1989. 
     According to “the push method,” the distal end of an endoscope is inserted into a patient&#39;s mouth and is passed through the esophagus into the stomach. After distension of the stomach by inflation with air, an entry site on the abdomen is identified, and an incision is made by passing a needle (or stylet) with an outer cannula through the abdominal wall and into the stomach. The needle is then removed while keeping the cannula in place. Next, a snare is inserted into the stomach via the endoscope and is looped over the distal end of the cannula. A first end of a flexible guide wire is then passed through the cannula and into the stomach where it is grasped by the snare, the second end of the guide wire remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the guide wire. 
     A catheter assembly is then inserted over the first end of the guide wire and is pushed over the guide wire towards its second end. The catheter assembly typically comprises a gastrostomy feeding tube, the gastrostomy feeding tube having a dome-shaped internal bolster disposed at its trailing end and having a tubular dilator serially connected to its leading end. The gastrostomy feeding tube and the internal bolster are typically made of a soft, biocompatible material, like silicone rubber, and may form a unitary structure. The dilator, which tapers in outer diameter from its trailing end to its leading end, is typically made of polyethylene or a like material which is stiffer than silicone but which still possesses some flexibility. Advancement of the catheter assembly over the guide wire continues until the front end of the dilator reaches the cannula and pushes the cannula out through the abdominal wall of the patient. The front end of the dilator is then pulled through the abdominal wall until the front end of the gastrostomy feeding tube emerges from the abdomen and, thereafter, the internal bolster at the rear end of the gastrostomy feeding tube engages the gastric wall. 
     With the internal bolster in place against the gastric wall, a proximal portion of the implanted gastrostomy feeding tube is then typically cut and removed from the implanted tube to reduce the externally-extending portion of the tube to a desired length. An external bolster is typically secured to the remaining implanted portion of the feeding tube to engage the abdomen in such a way as to prevent longitudinal movement of the feeding tube within the stoma tract. Additionally, a “Y-port” adapter is typically attached to the proximal end of the implanted feeding tube, the Y-port adapter being adapted to receive a pair of connector tips through which food and/or medications may be dispensed. In addition, a detachable locking clip is typically secured to the implanted feeding tube at a point between the external bolster and the Y-port adapter to prevent gastric fluids from escaping through the proximal end of the feeding tube when the feeding tube is not in use. 
     “The pull method” differs from “the push method” in that, after removal of the entry needle from the cannula, a first end of a suture is passed through the cannula and into the stomach where it is grasped by the snare, the second end of the suture remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the suture. The first end of the suture is then coupled to the leading end of a catheter assembly comprising a gastrostomy feeding tube having an internal bolster at its trailing end and a plastic fitting at its leading end. The plastic fitting has a barbed rear portion mounted within the leading end of the feeding tube and a conical front portion that serves as a dilator, said conical front portion tapering in diameter from the leading end of the feeding tube to a front tip. A wire loop is fixed to the front tip of the plastic fitting, the first end of the suture being tied to the wire loop. Using the second end of the suture, the catheter assembly is then pulled retrograde through the patient until the gastrostomy feeding tube emerges from the abdomen of the patient and the internal bolster engages the gastric wall of the patient. Next, as is the case in “the push method,” the implanted gastrostomy feeding tube is typically cut to a desired length, an external bolster is typically secured to the cut implanted tube, a Y-port adapter is typically attached to the proximal end of the implanted feeding tube, and a detachable locking clip is typically secured to the implanted feeding tube at a point between the external bolster and the Y-port adapter. 
     Although gastrostomies are the most common approach to the long-term feeding of patients unable to swallow, there are situations in which it is desirable to provide food directly into a patient&#39;s jejunum without passing through the patient&#39;s stomach. This has typically been accomplished by using a technique similar to that described above to implant a feeding tube into the jejunum, instead of into the stomach. One difficulty, however, that has been encountered in implanting feeding tubes into the jejunum has been in the piercing of the jejunum by the needle/cannula assembly (said assembly also referred to in the art as “an access needle”) so as to create an insertion hole through which a guide wire or suture may be inserted. This difficulty arises, in part, because the jejunum is narrow and thus hard to locate externally and, in part, because the jejunum is not fixed within the body at any particular location. As a result, not only is it difficult to actually pierce the jejunum with an access needle (the access needle frequently missing the jejunum or just pushing the jejunum aside without penetrating it), but even if the jejunum is actually pierced by the access needle, subsequent movement of the jejunum may cause the access needle to become dislodged therefrom. Consequently, it is generally desirable to use as small a diameter needle as possible to pierce the jejunum. This maximizes the chance that the jejunum, if struck by the access needle, will be pierced thereby and also minimizes the size of the insertion hole (which is desirable for obvious reasons). 
     One approach that has recently been devised to address the above-identified problems with piercing the jejunum involves piercing the jejunum with a small diameter needle, grabbing the distal end of the needle with an endoscopically-placed snare, using said small diameter needle (with the snare secured thereto) to anchor the jejunum against the abdominal wall, piercing the thus-anchored jejunum with an access needle at a site proximate to the first piercing site, transferring the snare from the small diameter needle to the cannula of the access needle, removing the small diameter needle from the jejunum, and then proceeding in the conventional fashion by removing the needle of the access needle from its cannula, inserting a guide wire or suture into the cannula for grabbing by the snare, etc. 
     Access needles of the type that are typically used in percutaneous endoscopic gastrostomies and in percutaneous endoscopic jejunostomies have their genesis in radiology and cardiology and typically come in two different varieties. One such access needle is referred to in the art as a Seldinger needle and comprises a solid metal needle (or stylet) removably mounted within a metal cannula. A plastic needle hub is fixed to the proximal end of the metal needle, and a plastic cannula hub is fixed to the proximal end of the metal cannula. The needle hub and the cannula hub are sized and shaped to permit a portion of the needle hub to be removably inserted into the cannula hub in such a way as to delimit insertion of the needle through the cannula. A tab is provided on the needle hub and a corresponding slot is provided on the cannula hub, said slot being adapted to receive said tab in order to permit said needle and said cannula to be placed in a particular rotational orientation relative to one another. The cannula hub is also shaped to include a lateral flange upon which a user may rest, for example, his forefinger and middle finger. 
     The other type of access needle commonly used to perform percutaneous endoscopic gastrostomies and jejunostomies is referred to in the art as an Angiocath needle and comprises a hollow metal needle removably mounted within a plastic cannula. A plastic needle hub is fixed to the proximal end of the metal needle, and a plastic cannula hub is fixed to the proximal end of the plastic cannula. The needle hub and the cannula hub are sized and shaped to permit a portion of the needle hub to be removably inserted into the cannula hub in such a way as to delimit insertion of the needle through the cannula. No means is provided in an Angiocath needle for fixing the rotational orientation of the needle relative to the cannula when the needle hub is inserted into the cannula hub. 
     In both a Seldinger needle and an Angiocath needle, the lengths of the needle and the cannula are such that, with the needle fully inserted into the cannula, only the needle tip extends distally beyond the distal end of the cannula. Seldinger needles typically have a smaller diameter than do Angiocath needles (20 gauge needle and 18 gauge cannula vs. 16 gauge needle and 14 gauge cannula, respectively); however, more doctors have been trained using Angiocath needles and, therefore, are more comfortable with and use Angiocath needles. 
     In both a Seldinger needle and an Angiocath needle, it is possible for the needle to be withdrawn unintentionally from its respective cannula as no means is provided in either device for longitudinally securing the needle hub to its respective cannula hub. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a novel method for implanting in a patient a feeding tube, such as a PEG tube, a PEJ tube or the like. 
     It is another object of the present invention to provide a method as described above which, as applied to PEJ tube implantation, overcomes at least some of the difficulties described above in connection with conventional PEJ implantation methods. 
     It is yet another object of the present invention to provide a novel access needle adapted for use in the above-described method. 
     Therefore, according to one aspect of the invention, there is provided an access needle, said access needle comprising, in a preferred embodiment, a stylet and a cannula, the stylet being slidably mounted within the cannula. A stylet hub is secured to the proximal end of the stylet, and a cannula hub is secured to the proximal end of the cannula. The stylet hub and the cannula hub are correspondingly threaded to permit the stylet and the cannula to be removably secured to one another. The stylet and the cannula are dimensioned relative to one another so that, when the stylet and the cannula are secured to one another, the stylet extends distally beyond the distal end of the cannula for a considerable distance. The distal end of the cannula is marked (e.g., by chemical etching) so as to be easily identifiable when viewed endoscopically. The respective diameters of the stylet and the cannula of the subject access needle are small, e.g., 20 gauge and 18 gauge, respectively. 
     According to another aspect of the invention, there is provided a method for implanting a PEJ tube in a patient, said method comprising, in a preferred embodiment, the steps of (a) providing an access needle wherein the distal end of the stylet extends distally for an appreciable distance beyond the distal end of the cannula; (b) inserting the distal end of the stylet, but not the distal end of the cannula, into the jejunum; (c) grabbing the distal end of the stylet with an endoscopically-positioned snare; (d) anchoring the jejunum against the abdominal wall of the patient using the snared stylet; (e) loosening the snare slightly while advancing the distal end of the cannula into the jejunum and into the loosened snare; (f) tightening the snare around the distal end of the cannula; (g) removing the stylet from the cannula; (h) inserting a guide wire or suture through the cannula and into the jejunum; and (i) proceeding in the conventional fashion to implant a PEJ tube into the patient using said guide wire or suture. 
     Additional objects, as well as aspects, features and advantages, of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration various embodiments for practicing the invention. The embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are hereby incorporated into and constitute a part of this specification, illustrate various embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings wherein like reference numerals represent like parts: 
         FIG. 1  is a side view of one embodiment of an access needle constructed according to the teachings of the present embodiment; 
         FIG. 2  is a partially exploded, perspective view of the access needle of  FIG. 1 ; 
         FIG. 3  is a side view of the stylet assembly shown in  FIG. 1 ; 
         FIG. 4  is a side view of the cannula assembly shown in  FIG. 1 ; 
         FIG. 5  is a fragmentary longitudinal section view of the cannula assembly shown in  FIG. 1 ; 
         FIG. 6  is a schematic view showing the access needle of  FIG. 1  just prior to its insertion into a patient during transillumination of the patient&#39;s jejunum; 
         FIG. 7  is a schematic view showing the access needle of  FIG. 1  inserted into the patient so that the distal end of the stylet of the access needle, but not the distal end of the cannula of the access needle, is inserted into the jejunum for capture by an endoscopic snare; 
         FIG. 8  is a schematic view showing the jejunum being held stationary against the abdominal wall by the combination of the access needle stylet and the endoscopic snare and also showing the access needle cannula being inserted into the jejunum; 
         FIG. 9  is a schematic view showing the loosened snare being moved from the distal end of the stylet to the distal end of the cannula; 
         FIG. 10  is a schematic view showing the snare tightened around the cannula, the stylet withdrawn proximally from the cannula and the distal end of an insertion wire about to be inserted through the cannula and into the jejunum; 
         FIG. 11  is a schematic view showing a PEJ tube coupled to an insertion wire and positioned in a patient using the pull method; and 
         FIG. 12  is a schematic view showing a PEJ tube implanted in a patient following practice of the present method. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to  FIGS. 1 and 2 , there are shown side and partially exploded perspective views, respectively, of a preferred embodiment of an access needle constructed according to the teachings of the present invention, said access needle being represented generally by reference numeral  11 . 
     Access needle  11  comprises a stylet assembly  13  and a cannula assembly  15 . 
     Referring now to  FIGS. 1 through 3 , stylet assembly  13  comprises a stylet (or sounding needle)  17  and a stylet hub  19 . Stylet  17 , which is preferably made of stainless steel, is a solid cylindrical member of small diameter, preferably  20  gauge, having a sharp, three-sided tip  21  at its distal end. 
     Hub  19  comprises a body  22  and a plug  23 . Body  22 , which is preferably made of plastic, is a generally cylindrical hollow member having a proximal end wall  25 , a circular side wall  27  and an open distal end. The outer surface of side wall  27  is provided with a plurality of longitudinally extending ribs  29  to facilitate the gripping of body  22 . The inner surface of side wall  27  is provided with a helical thread  31 , the purpose of which will be described below. Plug  23 , which is preferably made of plastic, is a generally cylindrical solid member fixedly mounted near its proximal end  33  within an opening (not shown) provided in end wall  25 , plug  23  extending coaxially with side wall  27  to define therebetween an annular space  28 . Stylet  17 , which extends coaxially with plug  23 , is fixed in distal end  35  of plug  23 , preferably by insert-molding. 
     Referring now to  FIGS. 1 ,  2 ,  4  and  5 , cannula assembly  15  comprises a cannula  45  and a cannula hub  47 . Cannula  45 , which is preferably made of stainless steel, is a tubular member of small diameter, preferably 18 gauge, that is appropriately dimensioned for stylet  17  to be removably inserted thereinto. A circumferential band  51 , which may be produced, for example, by chemical-etching or the like, extends proximally a short distance (e.g., approximately 3/10 inch or more) from the distal end  53  of cannula  45 . Band  51 , which is readily distinguishable in appearance, e.g., by color, from stylet  17 , permits facile differentiation of stylet  17  and cannula  45 , which is desirable for reasons to become apparent below. 
     Cannula hub  47 , which is preferably made of plastic, is a unitary member shaped to include a distal portion  61 , an intermediate portion  63 , and a proximate portion  65 . A plurality of longitudinal ribs  62  are formed on the outer surface of distal portion  61  to engage a protective sleeve (not shown) removably mounted over cannula  45  and stylet  17  when needle  11  is not in use. A plurality of laterally extending gripping elements  64  are formed on the outer surface of intermediate portion  63  to facilitate the gripping of hub  47  by a user. Proximate portion  65  is appropriately dimensioned to be received in annular space  28  of stylet hub  19 . Threads  66  are formed on the outside surface of proximate portion  65  and are adapted to engage thread  31 , thereby permitting hub  19  and hub  47  to be screwed (or twist-locked) together so as to prevent undesired relative longitudinal movement between stylet  17  and cannula  45 . 
     A longitudinal bore  67  is formed in hub  47 , bore  67  having a distal region  69  disposed in distal portion  61 , an intermediate region  71  disposed in intermediate portion  63  and a proximal region  73  disposed in proximate portion  65 . Distal region  69  is appropriately dimensioned to securely receive therewithin the proximal end of cannula  45 . Proximal region  73  has a comparatively large diameter to facilitate the insertion of stylet  17  thereinto, and intermediate region  71  tapers in diameter from proximal region  73  to distal region  69  so as to facilitate the insertion of stylet  17  into cannula  45 . 
     Stylet  17  and cannula  45  are dimensioned so that, when hub  19  and hub  47  are coupled together in the twist-lock manner described above, stylet  17  extends distally beyond distal end  53  of cannula  45  for a sufficient distance so that, as will hereinafter be described, tip  21  of stylet  17  may be inserted into a jejunum, without also inserting cannula  45  thereinto, and a snare may be tightened around the thus inserted portion of stylet  17 . In the present embodiment, stylet  17  extends approximately 1.5 inch beyond distal end  53  of cannula  45 , cannula  45  having a length of about 2.5 inches. (It should be understood, however, that the above dimensions of stylet  17  and cannula  45  may be varied. For example, stylet  17  and cannula  45  could be dimensioned so that cannula  45  has a length that is about ⅔ the length of stylet  17 .) 
     The use of access needle  11  in the implantation of a PEJ tube in a patient in accordance with the teachings of the present invention will now be described. Referring now to  FIG. 6 , after properly administering an anesthetic to a patient, an endoscope  8  having an illuminating channel is inserted through the patient&#39;s mouth and into the digestive tract of the patient until it reaches the patient&#39;s jejunum. Scope  8  is used to transilluminate the jejunum through the abdominal wall, thereby identifying the location of the jejunum to a surgeon in order to facilitate the surgeon&#39;s insertion of access needle  11  through the abdominal wall  10  and into the jejunum  12  of the patient. 
     Referring now to  FIG. 7 , the distal end of stylet  17 , but not cannula  45 , is then inserted through abdominal wall  10  and into jejunum  12  until it is visible to endoscope  8  through an observation channel therein. A snare  14 , which is inserted into the jejunum  12  through a snare channel of endoscope  8 , is then used to securely capture the inserted end of stylet  17  and to couple stylet  17  to snare  14 . With stylet  17  and snare  14  thus coupled, stylet  17  is pulled proximally so as to engage the wall of jejunum  12 . Further pulling of stylet  17  results in jejunum  12  being held stationary against abdominal wall  10 . 
     Referring now to  FIG. 8 , with jejunum  12  held stationary against abdominal wall  10  by snare  14  and stylet  17 , cannula  45  is de-coupled from stylet  17  (by unscrewing hub  19  from hub  47 ), and the distal end  53  of cannula  45  is then moved distally until it penetrates jejunum  12  through the opening previously created by stylet  17 . 
     Referring now to  FIG. 9 , snare  14  is loosened slightly from the inserted portion of stylet  17  and is then moved from stylet  17  to the inserted portion of cannula  45 . Snare  14  is then tightened around the inserted portion of cannula  45 . 
     Referring now to  FIG. 10 , with snare  14  now tightened around cannula  45 , stylet  17  is then withdrawn proximally from cannula  45 . At this point, it is the combination of cannula  45  and snare  14  that hold jejunum  12  stationary against abdominal wall  10 . With stylet  17  removed, the distal end of an insertion wire  16  (or a suture) is inserted through cannula  45  and into jejunum  12 . Snare  14  is then moved from around the inserted portion of cannula  45  to capture the distal end of insertion wire  16 . With snare  14  holding onto the distal end of insertion wire  16 , snare  14  and the distal end of insertion wire  16  are then withdrawn from the patient through the jejunum, the stomach and, ultimately, the mouth of the patient. 
     Referring now to  FIG. 11 , a PEJ tube  18  is then attached to the distal end of insertion wire  16 , which has previously been pulled out of the patient&#39;s mouth. The proximal end of insertion wire  16  is then pulled proximally, causing PEJ tube  18  to be pulled through the patient until its proximal end extends out through the abdominal wall of the patient and its distal end is disposed within the jejunum of the patient. 
     Referring now to  FIG. 12 , the distal end of PEJ tube  18  can be seen to have an enlarged end, which serves to anchor the distal end of PEJ tube  18  in jejunum  12 . An external bolster  20  may be positioned over PEJ tube  18  to hold PEJ tube  18  in place on the patient. With PEJ tube  18  thus implanted, liquid nutrition materials and/or medications may be fed into the jejunum through PEJ tube  18 . 
     It should be appreciated that, instead of positioning the PEJ tube in the patient by the pull-method as described above, the PEJ tube could alternatively be positioned in the patient using the push method. 
     It should also be appreciated that the foregoing method and device could also be used to implant a PEG tube in a patient or to implant other types of devices elsewhere in a patient. The present method and device could also be used, more generally, to position an organ within the body. 
     The embodiments of the present invention described above are intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. For example, although stylet  17  is described herein as being a solid member, stylet  17  could instead be hollow. In addition, although cannula  45  is disclosed herein as having a blunt distal end  53 , distal end  53  could instead be tapered. Moreover, whereas hubs  19  and  47  are described herein as being secured by a twist-lock, other removable securing means, such as a latch or a clip, could be used. Also, instead of using a band to differentiate stylet  17  and cannula  45 , stylet  17  and cannula  45  could be colored differently, stylet and/or cannula  45  could be provided with graduated depth markers, or stylet and/or cannula could be provided with surface markings, textures or patterns. It should also be understood that the diameters of stylet  17  and cannula  45  could be varied. In addition, barbs or like means could be provided on the distal end of stylet  17  and/or cannula  45  to facilitate the grasping thereof by the snare. Furthermore, various types of coatings (e.g., antithrombotic, antimicrobial, hydrophilic or hydrophobic) could be applied to access needle  11 . All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.