Abstract:
An endoscopic biopsy device having an outer sheath that is transparent, at least along a portion thereof, to allow visualization of at least a portion of the inside of the device. A distal portion of the outer sheath may be relatively more opaque or relatively less reflective to avoid glare that may otherwise result due to the sheath reflecting light from the endoscopic light source.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of priority to co-pending Provisional U.S. Patent Application Ser. No. 60/288,335, filed May 3, 2001 entitled BIOPSY FORCEPS DEVICE WITH TRANSPARENT OUTER SHEATH, the entire disclosure of which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to endoscopic instruments. More particularly, the invention relates to biopsy forceps for use in endoscopic procedures. For purposes herein, the term “endoscopic” is to be understood in its broad sense to include laparoscopic, arthroscopic, and other microsurgical instruments whether or not used with an endoscope. 
     BACKGROUND OF THE INVENTION 
     Endoscopic biopsy forceps are medical instruments which are used in conjunction with an endoscope for taking tissue samples from the human body for analysis. These instruments typically include a long (e.g., 8 foot) slender (e.g., several millimeters in diameter) flexible coil, one or more control wires extending through the coil, a proximal actuating handle coupled to the coil and control wire(s), and a biopsy jaw assembly coupled to the distal ends of the coil and control wire(s). The actuating handle typically moves the control wire(s) relative to the coil to effect a tissue sampling operation by causing the jaws to open and close to bite a tissue sample. A known biopsy forceps instrument is disclosed in U.S. Pat. No. 5,707,392 to Kortenbach. 
     An endoscopic biopsy procedure is performed utilizing an endoscope which is inserted into a body and guided by manipulation to the biopsy site. The endoscope typically includes a long narrow flexible tube with an optical lens and a narrow lumen for receiving a biopsy forceps. The practitioner guides the endoscope to the biopsy site while looking through the optical lens and inserts the biopsy forceps through the lumen of the endoscope to the biopsy site. While viewing the biopsy site through the optical lens of the endoscope, the practitioner manipulates the actuating handle to effect a tissue sampling operation at the distal end of the instrument. After a sample has been obtained, the practitioner and/or an assistant carefully withdraws the instrument from the endoscope while holding the actuating handle to maintain the jaws in a closed position. 
     Biopsy forceps are typically designed for single use, wherein the device is discarded after its first use. In an effort to reduce expenditures, some hospitals reuse medical devices after they have been re-sterilized. Similarly, some companies sterilize used medical devices and attempt to resell them at a discount. However, the re-sterilization process is not always effective at fully cleaning biopsy forceps designed for single use. After a single use, human blood and tissue may become trapped in the biopsy forceps compromising their subsequent performance and sterility. 
     SUMMARY OF THE INVENTION 
     The present invention provides a way to discourage such reuse or confirm adequate cleaning by allowing the practitioner and/or assistant to see into the device and inspect it for trapped blood or tissue which would indicate that the device was previously used and inadequately cleaned. In some embodiments, this is accomplished by providing an outer sheath that is transparent (in the visible spectrum), at least along a proximal portion thereof. A distal portion of the outer sheath may be relatively more opaque (in the visible spectrum) to avoid glare that may otherwise result due to the sheath reflecting light from the endoscopic light source. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially broken elevational view of a biopsy forceps device in accordance with an embodiment of the present invention, showing the jaw in the closed position; 
         FIG. 2  is a is a partially broken elevational view of a distal portion of the biopsy forceps device shown in  FIG. 1 , showing an example of a jaw having serrated edges in the open position; and 
         FIG. 3  is a is a partially broken elevational view of a distal portion of the biopsy forceps device shown in  FIG. 1 , showing an example of a jaw having straight cutting edges in the open position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. 
     Refer now to  FIG. 1  which illustrates a partially broken elevational view of a biopsy forceps device  10  in accordance with an embodiment of the present invention. The biopsy forceps device  10  includes an elongate shaft  12  having a flexible coil  16  covered by an outer polymeric sheath  14 . Polymeric sheath  14  is designed to allow a clinician to easily determine if device  10  had been used previously and/or if device  10  has been adequately cleaned and sterilized. 
     The polymeric outer sheath  14  can include a proximal portion  14 A and a distal portion  14 B. The lengths of the respective portions may be varied in different embodiments. For example, the length of the distal portion  14 B may correspond to the length of the biopsy forceps device  10  which extends beyond the distal end of the endoscope. Moreover, in some embodiments, the composition or properties of the proximal portion  14 A and the distal portion  14 B may differ. Alternatively, the composition or properties may be the same or similar. 
     Polymeric sheath  14  may comprise polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyolefin, polyethylene, polycarbonate, or other suitable polymer material. In some embodiments, all or a portion of proximal portion  14 A does not include any colorant such that it remains substantially transparent. This allows the physician and/or assistant to inspect the inner workings of the elongate shaft  12  for foreign material and proper function. If foreign material, such as blood and/or tissue, appears under the transparent outer sheath  14 A, the physician and/or assistant will be able to ascertain that the device  10  was previously used and insufficiently cleaned. 
     In some embodiments, the entire length of outer sheath  14  (i.e., both proximal portion  14 A and distal portion  14 B) may be comprised of substantially transparent materials. Alternatively, only a distal portion  14 B may be substantially transparent. However, it may be beneficial to alter the relative opacity of the polymeric sheath  14  in some uses. For example, if the transparent material of the proximal sheath portion  14 A were utilized in the distal sheath portion  14 B, the transparent material may create a halo effect during certain endoscopic visualization procedures. In particular, because the distal shaft portion  14 B may extend beyond the distal end of the endoscope, light emitted from the light source may tend to reflect off the distal sheath portion  14 B if a transparent material is used, thereby creating glare which appears as a halo during visualization. This halo effect may interfere with the ability of the physician to distinguish between different colors and, therefore, compromise the ability of the physician to distinguish between different types of tissue being sampled. 
     To reduce the potential halo effect, the distal sheath portion  14 B may be made relatively more opaque or relatively less reflective to visible light than the proximal shaft portion  14 A. Thus, the material or surface of the distal portion  14 B, relative to the proximal portion  14 A, may have modified pigmentation (color) or surface finish, which affect the opaqueness or reflectivity of the distal portion  14 B. As used herein, reflectivity is defined as the ratio of the light reflected from a surface to the total incident light. For example, the color of the distal portion  14 B may be black and the surface finish of the distal portion  14 B may be matte. The reflectivity of the distal portion  14 B may be less than about 0.50, preferably less than about 0.25, and ideally less than about 0.10. 
     The relatively high opaqueness or relatively low reflectivity of the distal portion  14 B may be provided by a number of means. In one embodiment, the distal portion  14 B comprises an extension of the proximal portion  14 A (e.g., a continuous homogenous extrusion) with a polymeric sleeve or coating disposed on the outside surface of the distal portion  14 B. An example of a suitable outer sleeve comprises a thin heat shrinkable tube made from a polymer mixed with a black colorant (e.g., black iron oxide). An example of a suitable coating comprises a permanent biocompatible black ink. Such outer sleeve or coating may have a relatively dark color (e.g., black) and a relatively low glare surface finish. The same type of polymeric sleeve or coating may be applied to the inside surface of the distal portion  14 B if the distal portion  14 B otherwise comprises a relatively transparent material. 
     In another embodiment, the proximal portion  14 A and distal portion  14 B are integrally formed by an alternating extrusion process or co-extrusion process. In this embodiment, the proximal portion  14 A and distal portion  14 B are formed in the same extrusion process wherein the proximal portion  14 A is formed by an extruded transparent polymer and the distal portion  14 B is formed by switching to an extruded opaque polymer. The opaque polymer may comprise the same transparent polymer loaded with a colorant or a different, but compatible, polymer loaded with a colorant. 
     In yet another embodiment, the distal portion  14 B comprises a separate tubular element thermally or adhesively bonded to the proximal portion  14 A. In this embodiment, the distal portion  14 B comprises an extruded opaque polymer tube segment or a tube segment having an opaque sleeve or opaque coating as discussed previously. Those skilled in the art will recognize that there are other suitable manufacturing processes conventional in the art to provide a functional distal sheath portion  14 B. 
     A distal effector assembly  40  is connected to the distal end of the elongate shaft  12 . Any one of a number of effector assemblies could be used without departing from the spirit of the invention. For example, effector assembly  40  may generally comprise a diagnostic or therapeutic device such as a biopsy device, a loop or snare, a cutting device, a needle or penetrating device, a device for delivering energy (such as cutting or ablating energy), an imaging device, a drug-delivery device, etc. In  FIG. 1 , the distal effector assembly  40  is shown as a biopsy forceps in a closed position, and in  FIGS. 2 and 3 , the distal effector assembly  40  is shown in the open position. 
     In some embodiments, a pair of control wires  18 A, 18 B are disposed in the flexible coil  16  extending through the elongate shaft  12 . The control wires  18 A, 18 B are axially displaceable relative to the flexible coil  16  and the outer sheath  14 . The proximal end of the control wires  18 A, 18 B are operably coupled to a proximal handle assembly  20  connected to the proximal end of the elongate shaft  12 . The distal ends of the control wires  18 A, 18 B are operably coupled to the distal effector assembly  40 . With this arrangement, the handle assembly  20  may be used to actuate the control wires  18 A, 18 B, which in turn actuate the distal effector assembly  40 . 
     The proximal handle assembly  20  includes a central shaft portion  22 , the proximal end of which includes a thumb ring  24 , and the distal end which includes a longitudinal bore  26 . A strain relief  30  extends across the junction between the proximal end of the elongate shaft  12  and the distal end of the proximal handle assembly  20 . A longitudinal slot  28  extends from the proximal end of the bore  26  to a point distal of the thumb ring  24 . The proximal handle assembly  20  also includes a displaceable spool  32  having a cross member  34  which passes through the slot  28  in the central shaft  22 . The cross member  34  includes a coupling means  36  for attaching the proximal ends of the control wires  18 A, 18 B. 
     Refer now additionally to  FIGS. 2 and 3  which illustrate partially broken elevational views of two different embodiments of a distal portion of the biopsy forceps device  10  shown in  FIG. 1 . The embodiment illustrated in  FIG. 2  shows a pair of jaws including serrated edges and a flat cutting knife. The embodiment illustrated in  FIG. 3  shows a pair of jaws having straight cutting edges without a cutting knife. 
     The distal effector assembly  40  includes a clevis  42  coupled to the distal end of the elongate coil  16 . The clevis  42  is coupled to a pair of forceps jaws  44 A, 44 B. The clevis  42  includes a pair of clevis arms  42 A, 42 B (see  FIG. 1 ) between which the jaws  44 A, 44 B are rotatably mounted on an axle pin  46 . Each jaw member  44 A, 44 B includes a distal cutting edge  48 A, 48 B, a proximal tang  50 A, 50 B, and a mounting hole  52 A, 52 B. The proximal tangs  50 A, 50 B are each coupled to the distal end of their respective control wires  18 A, 18 B, by way of holes  54 A, 54 B in the respective tangs  50 A, 50 B. With this arrangement, relative longitudinal movement between the central shaft  22  and the spool  32  of the proximal handle assembly  20  results in longitudinal movement of the control wires  18 A, 18 B relative to the coil  16 , such that the jaws  44 A, 44 B open and close, depending on the direction of relative movement. 
     Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departures in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.