Abstract:
An endoscopic device adapted for use in both diagnostic and therapeutic procedures, comprising, one or more sheaths; one or more endoscopes disposed within the sheath; one or more return electrodes disposed within the sheath; and one or more working channels disposed within the sheath.

Description:
This application claim benefit to Provisional Application No. 60/102,806 filed Oct. 2, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to endoscopes and more specifically to an endoscope which can be used as a diagnostic instrument and a therapeutic device. 
     BACKGROUND OF THE INVENTION 
     Endoscopes, which accommodate a bipolar energy source and which deliver the electrosurgical radiofrequency within a saline medium, are known in the art. However, interruption of the irrigation flow in such endoscopes may cause severe thermal injury to the surrounding tissues. Moreover, utilization of the preferred irrigating media, physiologic 0.9N saline, with an endoscope using a standard monopolar energy source is not feasible because a substantial portion of the radiofrequency energy from an electrosurgical generator unit, (ESU), to the endoscope, is dissipated within the ionic nature of the sodium chloride. To avoid dissipation, more non-conducting irrigation solutions are used such as water, glycine or sorbitol. However, these latter solutions may cause hyponatremia. Thus, use of monopolar energy has fallen out of favor with most endoscopic surgeons, whether they are performing urologic, gynecologic, arthroscopic or laparoscopic procedures. 
     In addition, endoscopes to date are not adapted to act as combined diagnostic and therapeutic instruments, and endoscopes that utilize a radiofrequency energy source generally require a ground-dispersive pad. These ground pads increase costs and may cause flesh burns. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of this invention to provide an endoscope which provides bipolar capabilities without the risk of thermal injury. 
     It is a further object of this invention to provide an endoscope which enables a physician to use a physiological saline solution as the irrigant without problems associated with dissipating electrosurgical energy. 
     It is a further object of this invention to provide an endoscope which can be used for both diagnostic and therapeutic procedures. 
     It is a further object of this invention to provide an endoscope with a bipolar return electrode and a working channel. 
     It is a further object of this invention to provide an endoscope with a coaxial electrode which does not require a ground-dispersive pad. 
     It is a further object of this invention to provide an endoscope with a bipolar return electrode and a working channel through which items such as grasping and biopsy forceps, radiofrequency energy or injectables may be passed. 
     It is a further object of this invention to provide an endoscope in which the outflowing irrigant is used to cool the coaxial cable of a bipolar resecting device. 
     It is a further object of this invention to provide an endoscope which provides more energy to a cutting loop and thus more heat, which in turn provides quicker and more efficient tissue removal and improved cauterization. 
     It is a further object of this invention to provide an endoscope with a bipolar return electrode and a working channel with which conductive physiologic irrigation solution may be used. 
     The preferred embodiment of the endoscopic device of the invention adapted for use in diagnostic and therapeutic procedures, comprises: one or more sheaths; one or more endoscopes disposed within the sheath; one or more return electrodes disposed within the sheath; and one or more working channels disposed within the sheath. The endoscopic device may further comprise one or more irrigation channels disposed within the sheath capable of transporting one or more irrigation fluids through the channel; and a coaxial cable, disposed within the sheath, in which one or more of the return electrodes is disposed so that one or more of the electrodes surrounds one or more of the irrigation channels so that the irrigation fluid is capable of cooling the return electrode. The endoscopic device also preferably comprises an electrical conductor disposed within the working channel, one or more light source channels, and/or a means for steering. 
     Another preferred embodiment of the endoscopic device of the invention that is capable of use as both a diagnostic instrument and a therapeutic device, wherein at least a portion of the device is disposed within a sheath, comprises: one or more lenses, one or more internal working channels; and one or more internal bipolar return electrodes. Similarly, this embodiment may also comprise a coaxial cable comprising at least one irrigation channel, wherein at least one of the return electrodes is disposed within the cable and wherein the irrigation channel is capable of cooling the return electrode. Further, at least one of the working channels may carry one or more items selected from a group consisting of forceps, one or more electrical conductors and one or more injectables. 
     The invention may utilize any type or size endoscope used to perform urologic, gynecologic, arthroscopic or laparoscopic procedures, including but not limited to cystoscopes, gastroscopes, colonoscopes, hysteroscopes and choledocoscopes. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiments and the accompanying drawings in which: 
     FIG. 1 is a perspective view of the preferred embodiment of the device of this invention; 
     FIG. 2 is a perspective view depicting the physician end (proximal end) of the device of FIG. 1; 
     FIG. 3 is a cross-sectional view taken through the shaft of the device of FIG. 1; 
     FIG. 4 is an end view of the patient end (distal end) of the device of FIG. 1; and 
     FIG. 5 is a schematic view of the device of FIG. 1 in use. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The endoscope of the invention for use as both a diagnostic instrument and a therapeutic device is designed for a physician&#39;s out-patient site. FIG. 1 illustrates a preferred embodiment of the multi-channel device of the invention, generally referred to as device  10 , which is adapted for use with an electrosurgical generator unit (ESU). The device of the invention will enable an endoscopist to cauterize tumors and lesions and biopsy a site without the additional need for a ground dispersive pad. An internal coaxial cable will function as the return electrode for the radiofrequency energy delivered through a separate working channel. The internally located return electrode allows the endoscopist to use physiologic saline as the irrigating fluid because the energy will be transmitted at the surgical site from the tip of the cauterizing electrode to the return electrode located in the coaxial cable. 
     At least shaft  12  of device  10  is encased in outer sheath  28  which may comprise stainless steel and/or a hydrophilic coated silastic which defines a central hollow core  13  into which a variety of standard endoscopes would fit, including, but not limited to, cystoscopes, gastroscopes, colonoscopes, hysteroscopes and choledocoscopes. Suitable endoscopes are readily available from companies such as Storz, Olympus, Wolf and ACMI. The sheath of the invention is designed to engage any of these endoscopes in a manner which would be understood by someone of ordinary skill in the art using a locking mechanism. 
     The endoscope depicted in the drawings, endoscope  14  is a 35 cm cystoscope having an outer diameter of about 16 Fr, although, as noted, the invention may be adapted for any type of endoscope. The length of device  10  will vary depending on the primary surgical subspecialty requirements and the endoscope used. Endoscope  14  may be focused with focusing means  16  commonly known in the art and typically includes a steering device known in the art such as steering device  26 . 
     As shown in FIG. 4, sheath  28  defines all inner tubular space  13  having an inner diameter of sufficient size to serve as a sleeve around endoscope  14 . The diameter of sheath  28  may taper down from the proximal end to the distal end. Sheath  28  also contains within its inner tubular space, a plurality of channels, e.g. channels  18 ,  20 , and  22 . Channel  18  is a fiber optic channel for carrying light from a xenon light source located near the proximal end of the device to the surgical site. Channel  22  is a working channel which enables the device of the invention to be used as a therapeutic device, as well as the diagnostic instrument by virtue of the endoscope. Working channel  22  enables the passage of items such as grasping or biopsy forceps, radiofrequency energy using an energy conducting loop, and/or injectables. The term injectable is used in its broadest sense and includes, but is not limited to, any liquid or solid item capable of being injected through the working channel. Working channel  22  is preferably has an inner diameter of about 3 Fr. 
     Channel  20  is preferably a coaxial cable through which electrical conductor  32  is concentrically located around irrigation channel  30 . Electrical conductor  32  acts as the bipolar return electrode or path for the electrosurgical energy which has been supplied by electricalsurgical generator unit  34  and transmitted to the surgical site by a conductor, such as a loop, (not shown), which is fed through working channel  22 . The bipolar return path is housed within device  10  to prevent direct coaptation between the energy from the ESU and the patient&#39;s tissue. Irrigation channel  30  preferably transports a physiologic saline irrigant, although a standard irrigant such as glycine, sorbitol or water can be used, to and from, respectively, the surgical site. Endoscope  14  typically includes ocular lens  15  at the proximal end of endoscope  14  and a surgical site lens (not shown) proximate the distal end of endoscope  14 . 
     Irrigation channel  30  is provided with the irrigant inflow at the proximal end of the device and irrigation channel  30  is preferably used to carry the irrigant suction or outflow away from the surgical site at the distal end of the device. Any resistive heating of conductor  32  is dissipated by the irrigant flowing through irrigation channel  30  because irrigant flowing through channel  30  hydrocools the return electrode, thus protecting surrounding tissue and the device from thermal damage. Conductor  32  is preferably a coaxial cable provided with external cord  36  for connecting conductor  32  with ESU  34 . Sheath  28 , together with the coaxial cable, enables a physician to utilize a physiologic saline solution as the irrigant, instead of water, glycine or sorbitol, because the internal coaxial cable acts as a return electrode which allows ESU  34  to act as a bipolar energy source. This design solves the problem of energy dissipation associated with an ionic saline irrigant when used in connection with a monopolar energy source and a standard ground dispersion pad. 
     An optical video system in conjunction with continuous flow may be used. Normal saline and a fluid warmer delivers the irrigant at a height approximately 60 cm above the operative field. 
     The sheath of the invention functions to disperse the monopolar oscillating radio frequency wave from the ESU. The current path travels from the active loop electrode, through the tissue at the surgical site and also through the saline, subsequently traversing the bipolar sleeve and returning to the ESU. The bipolar sleeve is thus defined as a return electrode. Thus, a dispersive ground pad is not necessary since the current path travels through the sleeve and the ionic effects of the saline irrigant are minimized. It is imperative that any tissue to be biopsied or otherwise removed be interposed between the endoscope loop and the bipolar sleeve in order to optimize the cutting efficacy. The surrounding tissue is insulated from the conductive component of the sleeve by its outer insulation. Use of the sheath of the invention does not mandate any selection parameters on the physician based upon anatomy. The sheath may be used using direct vision and does not require ancillary imaging systems. 
     Although specific features of the invention are shown in some drawings and not others, this is for convenience only as some feature may be combined with any or all of the other features in accordance with the invention. 
     Other embodiments will occur to those skilled in the art and are within the following claims: