Patent Publication Number: US-2007112336-A1

Title: Protective Cover for Endoscopic Tool

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to endoscopy, and specifically to a protective cover for sheathing an endoscopic tool after its withdrawal from a body passage.  
      The present invention refers also to a protective cover assembly and to an endoscopic system, which employs such protecting cover.  
      2. Summary of the Related Art  
      The use of a disposable sleeve (also referred to as a sheath) to cover an endoscope is well known in the art. Flexible endoscopes, such as colonoscopes, are notoriously difficult to clean and disinfect thoroughly, leading to problems of cross-contamination between patients. These problems can be avoided by covering the endoscope with a single-use sleeve, which is discarded after use.  
      Endoscopes commonly have working channels, running from a proximal port outside the body to a distal port at the distal end of the endoscope. When the distal end of the endoscope is inserted into the body, the working channel may be used, inter alia, to pass a surgical instrument through to the distal end of the endoscope in order to perform a surgical procedure, such as a biopsy. The working channel serves also for supplying vacuum, when suction is required. Instruments that are used in this manner become contaminated with biological matter from inside the patient&#39;s body. As the instrument is withdrawn from the body, it can spread the contamination from the interior of the working channel to the proximal tool port of the endoscope and to the hands of an operator.  
      Silverstein (U.S. Pat. No. 5,695,491) discloses a containment system for containment of at least a major portion of the shaft of the working tool. However, this containment system is adapted to contain the shaft remote from the endoscope and it is not designed to cover that portion of the shaft, which is between the containment container and the endoscope.  
      Methods for sheathing an endoscope while providing working channels that protect the endoscope from contamination are described, for example, in Silverstein (U.S. Pat. No. 4,646,722) and Sidall (U.S. Pat. No. 4,741,326), whose disclosures are incorporated herein by reference. These patents attempt to prevent contamination of the endoscope, either by adding disposable working channels external to the endoscope itself (Silverstein—U.S. Pat. No. 4,646,722) or by adding a disposable liner inside a working channel of the endoscope (Sidall—U.S. Pat. No. 4,741,326). They do not address the problem, however, of contamination that may be spread to the area around the proximal end of the endoscope and to the operator&#39;s hands as the surgical tool is retracted from the proximal port of the working channel.  
      An attempt to solve this problem is described for example in Aizenfeld (U.S. Pat. No. 6,908,428), which is incorporated herein by reference. This patent discloses methods and devices for use in sheathing an endoscopic tool as it is removed from the patient&#39;s body. Such sheathing prevents contaminants that may adhere to the tool inside the body from contacting the operator&#39; s hands, the handle of the endoscope, or other objects outside the patient&#39;s body. As a result, the likelihood of cross-contamination between patients is reduced, and the job of cleaning and disinfecting the endoscope and ancillary equipment between uses is simplified.  
      In embodiments of this solution, a sheathing assembly is provided, which comprises a sleeve dispenser mating with the proximal port of an endoscopic working channel, outside the patient&#39;s body. A flexible sleeve is typically fixed by its distal end to the dispenser, with the remainder of the sleeve bunched inside or otherwise held in a vicinity of the dispenser. An elongate endoscopic tool is passed through the dispenser and the working channel, until the distal end of the tool protrudes from the distal end of the endoscope. While the shaft of the tool is advanced through the dispenser and the proximal port of the working channel, the sleeve remains bunched at the dispenser. When the tool is retracted, however, the proximal end of the sleeve engages the shaft of the tool, so that, as the tool is withdrawn, the sleeve unfurls from the dispenser to cover the shaft of the tool, up to and including its distal end. All contaminants on the tool thus remain within the sleeve, while the outside of the sleeve remains clean and can be handled freely without spreading contamination.  
      Unfortunately this solution suffers from the fact that, when the tool is being retracted from the working channel, there exists a possibility that the distal end of the sleeve might be inadvertently torn and detached from the location where it is anchored to the sheathing assembly. Accordingly the tool might become exposed and contaminations adhered to the tool would spread to the environment.  
      Another disadvantage of the above solution lies in the fact that after the tool has been already retracted from the working channel and is protracted therein again, the sleeve bunches immediate before the sheathing assembly and impedes the doctor&#39;s fingers to grasp the tool as close as possible to the proximal port as would be desirable for easy and sure advancement of the tool inside the port.  
      Moreover, since the tool shaft deflects within the bunched portion this opposes the advancement of the tool and renders it difficult.  
      The present invention seeks to eliminate the above-mentioned disadvantages of the known solution. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       FIG. 1  is a schematic, pictorial illustration of a system for performing an endoscopic procedure, in accordance with an embodiment of the present invention;  
       FIG. 2   a  is a schematic, sectional view of a protecting cover in accordance with an embodiment of the present invention;  
       FIG. 2   b  is an enlarged view of the distal extremity of the proboscis portion.  
       FIGS. 3   a  is a schematic, pictorial illustrations showing how an endoscopic tool passes within the protective cover in accordance with various embodiments of the present invention;  
       FIG. 3   b  is similar to  FIG. 3   a , but there is a bag with a longitudinal fold;  
       FIG. 4  depicts a “milking” movement in a forward direction, which should be carried out for displacement of the endoscopic tool through the protecting cover;  
       FIG. 5  depicts a “milking” movement in a backward direction, which should be carried out for displacement of the endoscopic tool through the protecting cover;  
       FIG. 6  shows how the tool shaft deflects and loops within the protecting cover;  
       FIG. 7  is a view similar to  FIG. 6 , but shows the tool shaft with loops and figure eights within the protecting cover;  
       FIG. 8   a  shows transfer of a tissue sample to a sample container where the tool has been retracted;  
       FIG. 8   b  is a view similar to  FIG. 8   a , but the tool is within the container;  
       FIG. 9   a  depicts an embodiment of a protecting assembly comprising protective cover of the invention with an internal guiding tube within the bag;  
       FIG. 9   b  is a view similar to  FIG. 2   a , but showing an internal guiding tube within the bag; and  
       FIG. 9   c  is a view showing the exit end of the storing portion and the proboscis portion. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION  
      The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings.  
       FIG. 1  is a schematic, pictorial illustration of an endoscopic system  20  for performing an endoscopic procedure, in accordance with an embodiment of the present invention. System  20  comprises an endoscope  22 , having a working channel  24  passing therethrough. Channel  24  passes through endoscope  22  from a proximal port  32 , typically in or near an operating handle  30  of the endoscope, to a distal port  34  at the distal end of the endoscope. An endoscopic tool  26  is inserted through channel  24  in order to access an area adjacent to the distal end of the endoscope, within the patient&#39;s body. Typically, the endoscopic tool  26  comprises an elongate shaft  28 , with a working element  36  at its distal end and with a working handle  29  at its proximal end, as is known in the art. In the example shown in  FIG. 1 , working element  36  comprises biopsy forceps, which are operable to take a tissue sample within the patient&#39;s body, adjacent to distal port  34 . Alternatively or additionally, channel  24  may be used to apply suction to a body passage through distal port  34  or to apply liquid or gas to the area outside the distal port, as is likewise known in the art.  
      A disposable sheath may cover insertion tube of endoscope  22 , and channel  24  may likewise be internally sheathed, in order to protect the endoscope from contamination, e.g. as described in Sidall (U.S. Pat. No. 4,741,326). Alternatively or additionally, although channel  24  is shown in the figure as passing inside the endoscope, the endoscopic working channel may comprise a separate tube, typically disposable, which is fixed alongside the endoscope, as described, for example, in Silverstein (U.S. Pat. No. 4,646,722). The present invention is suited for use with either of these types of working channels.  
      Since at least working element  36  of tool  26  comes into contact with tissue and other biological matter inside the patient&#39;s body, the tool and the interior of the working channel (or the internal sheath which provides lining for the working channel) necessarily become contaminated during use. Furthermore, the interior of the working channel could be contaminated during suction and accordingly the tool shaft will be also contaminated when it passes through a contaminated working channel.  
      In order to prevent the spread of contamination from tool  26  to operating handle  30 , to the operator&#39;s hands and to other areas outside the patient&#39;s body, a protective cover  38  is attached to port  32 . Protective cover  38  is connected to port  32  so that a passage through the cover is aligned with working channel  24 . Tool  26  is then inserted through the cover into working channel  24  and can be used in the usual manner.  
       FIG. 2  is a schematic view of protective cover  38 , in accordance with an embodiment of the present invention. The protective cover is shown without the tool while being ready to receive it.  
      In the present embodiment, protective cover  38  comprises its main element, which is a storing portion  40  adapted for hosting therein shaft  28  of the tool during protracting thereof into or retracting from proximal port  32 . By virtue of this provision the tool is never exposed to the environment and any spreading of contamination therefrom is prevented.  
      The storing portion is configured as a flat, relatively wide, plastic bag, which has a proximal, entrance end  42  and a distal, exit end  44 . In practice the bag can be made of a high density polyethylene or other suitable plastic material and it has wall thickness of about 0.02-0.03 mm.  
      The tool can enter the bag through the proximal end and exit from the bag through the distal end. In practice the distal end can be temporarily closed by a disposable resilient plug to prevent the early exit of the tool shaft from the distal end.  
      The entrance end  42  of the bag is provided with a one-way plug  46 , which ensures that the tool shaft can be only protracted through the entrance end, while its retraction from the bag is prevented. Instead of the one-way plug one can use a means suitable for securing the rear part of the tool shaft at the entrance end and allowing only protracting of the tool shaft in the storing portion. An example of such a means could be a collet, similar to that used for holding cylindrical pieces in a lathe, or it could be an eccentric fixture.  
      The further component of the protective cover is a proboscis portion  50 , which is coupled to the exit end  44  of the storing portion.  
      It is seen that to the exit end  44  of the bag is coupled a proximal end  48  of the proboscis portion  50 . The proboscis portion is configured as a sleeve made from easily pliable plastic material. A distal end  52  of the proboscis portion is anchored to an adapter  54 , which, in its turn, terminates by a connecting fitting  56  attachable to proximal port  32 .  
      Proximal extremity  48  of the proboscis portion is connected by an appropriate connection to distal end  44  of the storing portion. The distal extremity  52  of the proboscis portion is anchored to adapter  54 , e.g. by an elastic ring  53  put over a groove made in the adapter. This arrangement is schematically depicted on enlarged fragment of  FIG. 2 . Alternatively the anchoring can be accomplished by a conical ring put over the distal extremity so as to be in snapping relationship therewith.  
      Referring now to  FIG. 3   a  it is shown the situation when the tool has been inserted into storing portion  40  through its proximal, entry end  42  and then advanced in the forward direction until distal end of the tool shaft with working element  36  has passed the exit end  44 , the proboscis portion  50  and protrudes outside the cover assembly through adapter  54 . The proboscis portion is made of a pliable plastic material and is preferably provided with corrugations or folds to enable easy and convenient squeezing by fingers. At the same time the material of the proboscis portion should provide good friction between the tool shaft and the proboscis portion. Examples of suitable plastic materials are polyurethane, polyethylene, etc. The wall thickness of the proboscis portion should be selected to permit easy squeezing and reliable grasping the tool shaft by fingers. In practice the wall thickness is about 0.5 mm.  
      Once adapter  54  is connected by fitting  52  to port  32 , the endoscopic tool can be protracted into the working channel, e.g. for taking a biopsy sample. Then the tool shaft can be retracted from the proximal port, the adapter can be disconnected from the proximal port and the biopsy sample can be transferred in a dedicated sample container. For protracting or retracting of the tool shaft through the storing portion one should grasp the tool shaft by fingers in an initial position close to the connecting fitting, as shown in  FIGS. 4 and 5 , and then to displace the tool shaft forward or backward while squeezing the corrugations of the proboscis portion. With reference to  FIGS. 4 and 5  it is shown how doctor&#39;s fingers  58 ,  60  initiate squeezing of the proboscis portion while grasping the tool shaft. Then the shaft is displaced in the forward or backward direction as designated by respective arrows F,B. The tool shaft is displaced by virtue of a “milking” movement, which comprises repetitive advancing the shaft forward or backward from the initial position, then release the shaft in a new position, while still grasping the proboscis portion, and then returning the fingers in the initial position along with the proboscis portion.  
      In the prior art endoscopes, which do not employ protecting covers, the doctors are familiar with protracting the tool into the port and retracting it from the port by the same “milking movement” and therefore they should not change their habit while using the protective cover of the present invention.  
      It can be readily appreciated that, when the doctor&#39;s fingers advance the tool shaft forward to protract it into the port, the corrugations of the proboscis portion bunch between the initial position and the adapter. This situation is depicted in  FIG. 4 , in which the bunched region is designated by reference numeral  62 . The region of the proboscis portion behind the fingers is designated by reference numeral  64 . When the region  62  bunches, the region  64  straightens up. At the same time when the shaft is advanced backward, i.e. is retracted from the port, region  64  bunches and region  62  straightens up. It should be borne in mind, however, that, when either the region  62  or  64  bunches, it nevertheless does not provide a hindrance for protracting or retracting the tool shaft through the proboscis portion and the doctor&#39;s fingers can always remain close to the proximal port of the working channel. By virtue of this provision the advancement of the tool shaft through the port is easy, reliable and efficient.  
      Attention is now called to  FIGS. 6 and 7 , which show how the tool shaft  28  is gathered in the storing portion  40  and is stored therein being sheathed and thus prevented from exposure to the environment. In accordance with the present invention the storing portion is configured and dimensioned in such a manner that when the tool shaft retracts from proximal port  32  of the endoscope, the interior of the storing portion urges the tool shaft to elastically deflect and make loops  66  inside the storing portion. By virtue of this provision the tool shaft is compactly stored. Depending on the bag&#39;s size and configuration the tool shaft can deflect by making loops and even figure eights  68 . This situation is seen in  FIG. 7  depicting the shaft gathered in a compact configuration consisting of loops and figure eights.  
      In practice the protective cover of the invention is used as follows. First, the preparation step is carried out during which the tool shaft is entered into proximal end  42  of the storing portion and then pushed towards distal end  44  through proboscis portion  50  until working element  26  of the tool slightly protrudes outside from fitting  56 . For carrying this out distal end  42  of the storing portion should be aligned with its proximal end  44 . To make the alignment procedure easier it is advantageous to provide the bag with a longitudinal fold extending between distal end  42  and proximal end  44 . This situation is shown in  FIG. 3   b.    
      In an embodiment of the invention a tubular guide can be provided within the storing portion for aligning the distal and proximal end of the storing portion. The guide facilitates alignment between the distal end of the tool shaft and the proboscis portion and by virtue of this provision entering the tool shaft in the proximal end of the proboscis portion becomes easy and convenient. This embodiment will be explained in more details with reference to  FIG. 9 .  
      After inserting the tool in the storing portion the connection fitting  56  is attached to proximal port  32  of the endoscope and the tool is protracted thereinto until tool&#39;s operating handle  29  is in vicinity to proximal end  42  of the storing portion as shown in  FIG. 3 . In this position the rear portion of the tool shaft can be secured at the proximal end of the bag  40  (if instead of the one-way plug an alternative means for securing the tool is used).  
      After completing the preparation step the tool shaft can be either retracted from proximal port  32  or protracted thereinto by virtue of the above described “milking” movement applied to proboscis portion  50 .  
      It might be advantageous if the proboscis portion is made of a material, which is easily pliable and at the same time is also elastically stretchable. An example of a suitable material can be silicon or polyurethane. Since elastically stretchable proboscis portion would act as a spring, the probability for its detachment from adapter  52  is much less.  
      Up to now an embodiment of the protecting cover assembly has been described, in which the protective cover constitutes an item, which is independent from the endoscopic tool. This item can be supplied separately from the tool and for its use during the endoscopic procedure one should complete the above described preparation step.  
      However, one can contemplate also a situation, in which the protective cover assembly and the tool are supplied as a protective cover assembly, i.e. as a ready for use combination, in which the endoscopic tool had been already deployed within the storing portion. In such protective cover assembly there is no need in preparation step and the endoscopic tool is ready for protracting into proximal port  32  of an endoscope upon connection fitting  56  to the proximal port  
       FIGS. 8   a  and  8   b  provide a schematic, pictorial illustration showing transfer of a tissue sample from working element  36  of the endoscopic tool to a sample container  70 . In  FIG. 8   a  is seen the tool when it has been retracted completely from the endoscope, and adapter  54  has been detached from port  32 . Then adapter  54  is coupled preferably by the same fitting  56  to a neck  72  of container  70 , as shown in  FIG. 8   b . At this point, assuming working element  36  to comprise biopsy forceps holding a biopsy sample captured inside the patient&#39;s body, for example, the operator may advance working element  36  into container  70  through neck  72 , and may then open the forceps, releasing the biopsy sample into the container. Thus, working element  36  and the sample that it captures are never exposed to the environment outside storing portion  40 , proboscis portion  50  and container  70 .  
      Now with reference to  FIG. 9  an embodiment of the protecting assembly will be explained, in which the storing portion is provided with an internal guiding tube.  
      Since the protecting assembly of this embodiment has the same main components as the assembly explained previously in connection with  FIG. 3   a , the similar components are designated by the same reference numerals. Among the similar components are storing portion  40  provided with respective entrance and exit end  42 ,  44  as well as the proboscis portion  50  provided with adapter  54 . As in the previous embodiment the storing portion comprises a plastic bag, which is shown in  FIG. 9   a  as being crumpled in a compact state such that the distance between the entrance end and the exit end can be shortened. Within the bag there is provided an inner guiding tube  74 , which bridges between the entrance end and the exit end and thus brings them in alignment with a possibility for fluid communication therebetween. The proximal end of the guiding tube is detachably connected to the entrance end  44  of the storing portion, while the distal end of the guiding tube is secured in the exit end  42  of the storing portion. The tube is made of a relatively rigid plastic material, e.g. PVC, and by virtue of this provision, as soon as the shaft is being protracted through the entrance end, it is guided within the guiding tube until it reaches the exit end and protrudes therefrom. During protracting of the tool, the proximal end of the guide tube detaches from the entrance end  44  and the storing portion unfolds from the crumpled state to the flat state. This situation is shown in  FIG. 9   b , in which it is seen that tool shaft  28  extends along the storing portion  40  and along the guiding tube  74 . Distal end  36  of the tool protrudes from the storing portion and proximal end of the tool is secured by a fixture  46  at the entrance end  44  of the storing portion. Proximal end of the guiding tube is detached from the exit end of the storing portion. The storing portion is flat and not crumpled.  
      By virtue of the guiding tube the shaft reaches the exit end and easily passes through the storing portion even in a situation when the storing portion is folded.  
      It might be advantageous if the proboscis portion consists of two sections, namely a long section  501  and a short section  502 . Both sections are corrugated and the diameter of the long section is more than the diameter of the short section. During the “milking” movement the operator&#39;s fingers grasp the short section and squeeze the long section.  
      In  FIG. 9   c  is shown the exit end of the storing portion and the proboscis portion. A disposable stopper plug  76  is provided at the distal end of the proboscis portion. The plug is made of a resiliently deformable material and is detachably connectable to adapter  54 . The plug is retained in place during the preparation step when the tool is being advanced along the storing portion until the distal end thereof reaches the distal end of the proboscis portion. To make the advancement easier, an auxiliary guiding tube  78  can be provided within the proboscis portion. When the tool reaches the distal end, the plug is taken out from the adapter and thus the storing assembly can be connected to the port of the endoscope and the tool can be protracted thereinto.  
      Protective cover of the invention is particularly suited for use with flexible endoscopes that are inserted into the gastrointestinal tract, such as colonoscopes and gastroscopes. Alternatively, the principles of the present invention may be applied to sheath tools that are inserted through lumens in medical probes of other types, such as endoscopes (both rigid and flexible) and catheters used in other body passages and in other therapeutic and diagnostic procedures.  
      One should bear in mind that the storing portion need not necessarily be configured as a flat bag, i.e. as a substantially two dimensional receptacle. One can contemplate an embodiment in which the storing portion is configured as a ball for rugby, i.e. as a three dimensional receptacle.  
      It will thus be appreciated that the embodiments described above are cited by way of example, and 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 which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.