Patent Publication Number: US-2011077558-A1

Title: Ultrasound endoscopic system

Description:
FIELD OF THE INVENTION 
     Embodiments of the present invention relate to an endoscopic system. In particular, exemplary embodiments of the present invention relate to endoscopes to perform image guided hemostasis. Embodiments of the present invention also cover methods of using such devices. 
     BACKGROUND OF THE INVENTION 
     An endoscope is a flexible instrument introduced into the body for diagnostic or therapeutic purposes. Typically, these devices are inserted into the body through a natural opening, and are delivered to a work site inside the body through a body channel, such as, for example, the esophagus. Endoscopes are widely used for diagnostic and therapeutic purposes inside a body. There are many different uses for endoscopes, and typically, endoscope designs may be varied to optimize their performance for an intended application. For example, there are upper endoscopes for examination of the esophagus, stomach and duodenum, urethroscopes for examining the urethra and bladder, colonoscopes for examining the colon, angioscopes for examining the blood vessels and heart, bronchoscopes for examining the bronchi, laparoscopes for examining the peritoneal cavity, arthroscopes for examining joint spaces, sigmoidoscopes for examining the rectum and sigmoid colon, etc. Each of these devices may include features to optimize their performance for their application. Although embodiments of the current invention may be broadly applied to an endoscopic instrument used for any diagonostic or therapeutic procedure, for the sake of brevity, embodiments of the invention will be described as being applied to an endoscope especially configured to perform image guided hemostasis. 
     In typical applications, a distal end of an endoscope may be inserted into the body through a natural anatomic opening, such as, for example, the mouth, rectum, vagina, etc. In some embodiments, an endoscope may be inserted through an organ wall to access sites outside of a body lumen. In some embodiments, an endoscope may also be delivered percutaneously, through a trocar or a PEG tube, for example. The endoscope may be pushed into the body such that the distal end of the endoscope then proceeds from the point of insertion to a region of interest (work site) within the body by traversing a body channel. In the case of the exemplary embodiment described in this application, the work site may include a bleeding ulcer in the stomach. The endoscope may include one or more lumens extending longitudinally from the proximal end to the distal end of the endoscope. These lumens may deliver various diagnostic/treatment devices to the work site within the body. In some cases, an endoscopic device may be reused for different medical procedures after sterilizing the endoscope thoroughly after each procedure. Although sterilization of the endoscope may decrease the possibility of infection being transmitted from one patient to another, the potential for transmitting disease due to insufficient sterilization may still exist. Therefore, it may be desirable to develop a low cost single-use endoscope that is configured to perform a desired medical procedure. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention may include an endoscopic device. The endoscopic device may include an elongate section extending from a distal end to a proximal end. The elongate section may be configured to be inserted into a cavity of a body, and may include an end effector at the distal end of the elongate section. The end effector may have an end face. The end face may include a transducer configured to vibrate in response to an electric current. The elongate section may also include a conduit configured to circulate coolant to the end effector. 
     Various embodiments of the invention may include one or more of the following aspects: the transducer may be configured to vibrate in response to an electric current at RF frequency; the transducer may be one of a dome shaped, pyramid shaped and a frustoconical shape; the transducer may be configured to vibrate in response to laser energy; a front side of the transducer may be configured to contact a body tissue and a back side of the transducer may be in fluid communication with the conduit; the back side may form a wall of a reservoir configured to receive the coolant; the end effector may include an inlet channel and an outlet channel in fluid communication with the reservoir; the end effector may include a thermoelectric cooler; the end effector may include an imaging device configured to provide an image of a region within the cavity; the end effector may have a substantially cylindrical shape having a first diameter at a first end and a second diameter at a second end, the first diameter may be smaller than the second diameter; a diameter of the end effector may transition step-wise from the first diameter to the second diameter at a location between the first end and the second end; the distal end of the elongate member may be disposed circumferentially outwards the first end of the end effector; the transducer may be made of a piezoelectric material; the transducer may include a coating of a metal; the transducer may include a coating of a Teflon based material; the transducer may include a non-stick coating material; the end effector may include a reservoir configured to maintain a supply of a coolant, an inlet channel conduit configured to deliver the coolant to the reservoir, and an outlet channel configured to remove the coolant from the reservoir; the elongate member may include a fluid conduit that mates with the inlet channel and a separate fluid conduit that mates with the outlet channel; the inlet channel and the outlet channel may be configured to fluidly couple to a heat exchanger; the inlet channel and the outlet channel may be configured to be fluidly coupled to a pump; the device may further including one or more control mechanisms that are configured to control an operation of the endoscope; the one or more control mechanisms may include a power supply configured to deliver an electric current at RF frequency to the transducer; the end face may include one or more illumination devices configured to illuminate the cavity; and the device may be used for visualization in conjunction with another visualization means. 
     An embodiment of the invention may include a method of using an endoscopic device. The method may include inserting a distal end of the device into a cavity of a body. The device may include an end effector having a transducer. The transducer may be configured to mechanically vibrate in response to an electric current. The method may also include pressing the transducer against tissue within the body, and vibrating the transducer against the tissue to heat the tissue. The method may further include circulating a coolant through the end effector to remove heat, and retracting the endoscope from the body. 
     Various embodiments of the invention may include one or more of the following aspects: pressing the transducer against tissue includes pressing a front side of the transducer against bleeding tissue; retracting the endoscope includes retracting the endoscope after stopping the bleeding; circulating the coolant includes flowing the coolant against a back side of the transducer; circulating the coolant includes circulating the coolant through the end effector within the body, and a heat transfer device outside the body; the method may further include obtaining a visual image of a region of the cavity using the imaging device; the transducer may be a piezoelectric based material; circulating the coolant may include circulating the coolant to prevent excessive heating of the tissue; the transducer may vibrate in response to an electric current at RF frequency; the device may be inserted into the body intraluminaly, transluminaly, or percutaneously; the heating of the tissue may be part of a tissue ablation process, a process to activate/melt devices, a process to fasten tissue, a process of vessel occlusion, or a process of disease treatment; and the method may also include using the imaging device in addition to a different imaging device for visualization. 
     An embodiment of the invention may also include a method of using a medical instrument. The method may include inserting the medical instrument into a body cavity. The medical instrument may include a transducer coupled to a distal tip thereof. The method may also include pressing the distal tip against an anatomic stricture within the body cavity, and activating the transducer to vibrate the distal tip and allow the medical instrument to traverse the stricture. 
     Various embodiments of the invention may also include circulating a coolant in the medical instrument to remove heat from the transducer; modulating a flow of coolant in the medical instrument to control a stiffness of the medical instrument; and activating the transducer includes activating the transducer using an electric current at RF frequency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic view of an embodiment of an endoscope performing an exemplary endoscopic procedure. 
         FIG. 2  is an illustration of the endoscope of  FIG. 1 . 
         FIGS. 3A and 3B  are isometric and cross-sectional illustrations of an end effector of the endoscope of  FIG. 2 . 
         FIG. 4  is an illustration of a method of using an embodiment of the current invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  depicts an exemplary endoscope  20  performing an exemplary hemostasis procedure of a peptic ulcer  18  on a patient. Endoscope  20  may be inserted into stomach  12  through the esophagus  14 , and positioned in stomach  12  such that a distal end  22  of endoscope  20  may be positioned proximate a peptic ulcer  18  (work site) on stomach wall  16 . A proximal end  28  (see  FIG. 2 ) of endoscope  20  may extend out of the body of the patient and may be controlled to perform hemostasis of ulcer  18 . It should be emphasized that the medical procedure illustrated in  FIG. 1  is exemplary only, and that endoscopes of the current disclosure may be applied to any endoscopic application known in the art. It should also be emphasized that the illustration of the endoscope in  FIG. 1  is exemplary only, and that endoscopes  20  of the current disclosure may also be guide tubes, catheters or the like without limitation. 
       FIG. 2  illustrates endoscope  20  used in the hemostasis procedure of  FIG. 1 . Endoscope  20  may include a flexible elongate member  26  extending between the proximal end  28  and distal end  22 . Elongate member  26  may be flexible so as to enable endoscope  20  to bend and pass through tortuous body passages as distal end  22  of endoscope  20  advances to the location of ulcer  18  (see  FIG. 1 ). The proximal end  28  of endoscope  20 , in some embodiments, may include an actuation device configured to operate endoscope  20 . Distal end  22  of endoscope  20  may include an end effector  24  that may include devices/instrumentation suited for hemostasis of ulcer  18 . End effector  24  may be operatively coupled to, and controlled by, the actuation device. In some embodiments, in place of a discrete actuation device, cables and conduits extending from the proximal end  28  may be coupled to other devices, such as power supplies, pumps, and visual displays. 
     Elongate member  26  may include a plurality of lumens running longitudinally therethrough. These lumens may extend between distal end  22  and proximal end  28 . These lumens may serve as conduits for supplying electrical signal, suction, fluid, light, vision, and/or other supplies to distal end  22  and end effector  24 . 
       FIGS. 3A and 3B  illustrate embodiments of end effector  24  that may be coupled to distal end  22  of endoscope  20 .  FIG. 3A  illustrates an isometric view, and  FIG. 3B  illustrates a cross-sectioned view of the end effector  22 . In the discussion that follows, reference will be made to both  FIGS. 3A and 3B . Although end effector  24  is depicted as having a substantially cylindrical external shape with an end face  36  at one end, it is contemplated that end effector  24  may have any other shape, without limitation. 
     In some embodiments, end effector  24  may include a housing  21  that extends from a proximal end (hereinafter referred to as “first end  32 ”) having a first diameter to a distal end (hereinafter referred to as “second end  34 ”) having a second diameter, larger than the first diameter. The external diameter of the housing  21  may transition stepwise from the first diameter to the second diameter at a location between the first and the second end  32 ,  34 . The first end  32  of housing  21  of end effector  24  may be coupled to a distal end of elongate member  26 , and the second end  34  may be coupled to the end face  36 . In some embodiments, the distal end of elongate member  26  may be slid over the first end  32  of housing  21  such that an internal surface of the distal end of elongate member  26  may mate with, and slide over, an external surface of the first end  32  of housing  21 . In some embodiments, key ways or slots  23  on external surface of first end  32  may mate with corresponding features on the internal surface of the distal end of elongate member  26 , to align conduits in housing  21  to respective mating conduits in elongate member  26 . In the assembled configuration (shown in  FIG. 2 ), endoscope  20  may be substantially tubular having a substantially uniform external diameter from proximal end  28  to distal end  22 . 
     End face  36  may be fixedly or removably attached to housing  21 , and may include an imaging device  38  coupled thereto. Imaging device  38  may be configured to deliver a video image of an area in front of distal end  22  of endoscope  20 . This video image may enable endoscope  20  to be inserted and positioned proximate ulcer  18 , and perform hemostasis of ulcer  18  guided by the image. Although any device (such as, a CCD camera) capable of obtaining an image of the work site within the body may be used as imaging device  38 , in some embodiments, imaging device  38  may include a CMOS video chip and/or an optical fiber. One or more lumens extending through elongate member  26  may include cables that deliver electrical supply to power the imaging device  38 , and cables that deliver signals from imaging device  38  to proximal end  28  of endoscope  20 . These cables may be electrically coupled to video monitors or other display devices that are configured to display an image of the work site thereon. 
     Illumination devices  42 A and  42 B (such as bulbs, solid state light emitting devices (LEDs), etc.) may also be coupled to end face  36  to illuminate the work site. Cables, coupled to these illumination devices  42 A and  42 B, may also extend to proximal end  28  through lumens passing through elongate member  26 , to deliver electrical power and other signals to these illumination devices  42 A and  42 B. Although  FIGS. 3A and 3B  depicts two illumination devices  42 A and  42 B positioned on either side of imaging device  38 , it is contemplated that other embodiments of endoscope  20  may include a different number of illumination devices arranged in different patterns on end face  36 . 
     End face  36  may also include a transducer  44  coupled thereto. Transducer  44  may have any shape, geometry, and dimension (for example, dome shaped, pyramid shaped, frustoconical shaped, etc.) to suit the treatment. Transducer  44  may include a high intensity ultrasound transducer. Transducer  44  may be made of a piezoelectric ceramic material (such as, for example, PZT-8), which may respond mechanically to an electrical excitation. Transducer  44  may include a front-side  44 A and a back-side  44 B spaced apart from each other. In some embodiments, front-side  44 A and a back-side  44 B may be disposed substantially parallel to each other. One or both of front-side  44 A and back-side  44 B of transducer  44  may be plated with a metal (such as, for example, silver, gold, nickel, etc.). In some embodiments, front-side  44 A may alternatively or additionally be coated with a biocompatible material that may reduce stickiness of transducer  44  to body tissue (such as, for example, a Teflon based or other non-stick coating). In response to an electric current of RF frequency (such as, for example, from about 3 MHz-20 MHz), transducer  44  may generate mechanical vibrations. When front-side  44 A of transducer  44  is pressed against body tissue, these mechanical vibrations may penetrate into tissues. The tissues may absorb these mechanical vibrations and generate heat. When transducer  44  is pressed against a bleeding ulcer  18 , the heat and the pressure may make the walls of the surrounding tissue locally fuse together to seal ulcer  18  and surrounding blood vessels to stop the bleeding. Although transducer  44  is described in a procedure to seal ulcer  18 , in general, transducer  44  may be applied in any procedure to apply heat to an area. For example, transducer  44  may be applied in a procedure to provide heat to ablate tissue, activate/melt devices (fasteners, etc.), fasten tissue, vessel occlusion (cancer, etc.), disease treatment, etc. 
     To prevent over-heating of the surface of the body tissue at the contact area, and to inhibit heat related effects on transducer  44  and surrounding devices, transducer  44  may be cooled from the back-side  44 B. Cooling of transducer  44  may be achieved by keeping back-side  44 B of transducer  44  in contact with a circulating coolant. Back-side  44 B may form a wall of a reservoir  46 , enclosed by housing  21 , and configured to maintain a supply of the coolant in contact with back-side  44 B. The coolant may be circulated through reservoir  46  to transfer heat from distal end  22  within the body to proximal end  28  outside the body. At proximal end  28 , the coolant may be circulated through other devices, such as, a heat exchanger and a pump, which may help in circulating a cool coolant through reservoir  46 . An inlet channel  48 A may deliver the coolant from proximal end  28  to reservoir  46 , and an outlet channel  48 B may deliver the coolant from reservoir  46  to proximal end  28 . Inlet channel  48 A and outlet channel  48 B may comprise the lumens running longitudinally through elongate member  26 . 
     Any fluid (such as, for example, water, saline, oils, refrigerants, etc.) may be used as coolant. Although a liquid may typically be used as coolant, it is contemplated, that in some embodiments, a gaseous coolant may be used to cool transducer  44 . Using the coolant to prevent over heating of transducer  44  may reduce the likelihood of tissue charring and may extend the working life of transducer  44 . Although the description above, and  FIG. 3B , depicts the back-side  44 B of transducer  44  as forming a wall of reservoir  46 , other configurations are also contemplated. For example, in some embodiments, a discrete reservoir  46  may be eliminated, and heat from transducer  44  may be transferred to the coolant passing from a continuous inlet channel  48 A to outlet channel  48 B. Cooling of transducer  44  may also be affected or enhanced with a thermoelectric module situated in the vicinity of transducer  44 . 
     In addition to inlet channel  48 A and outlet channel  48 B, housing  21  of end effector  24  may also include other channels  49  that may deliver cables coupled to the illumination devices  42 A and  42 B, imaging device  38 , transducer  44 , and any other device on end face  36  to the actuation device or other control devices on proximal end  28 . The actuation device (or the other control devices) may include controls that control the operation of endoscope  20 . These controls may include switches or knobs that activate the devices (such as, illumination devices  42 A and  42 B, imaging device  38 , transducer  44 ) coupled to end face  36 , and initiate and regulate the amount of coolant circulated through end effector  24 . 
     A method  100  of using endoscope  20  in an exemplary hemostasis procedure of tissue, for example ulcer  18  of  FIG. 1 , will now be described.  FIG. 4  is a flow chart that illustrates the steps involved in the exemplary hemostasis procedure. Endoscope  20  may be prepared to be inserted into a body cavity (step  110 ). In some embodiments, this step may include cleaning endoscope  20  and/or coupling end effector  24  to the distal end of elongate member  26 . Typically end effector  24  may be permanently affixed to elongate member  26  during manufacture. The external surfaces of endoscope  20  may also be lubricated for ease of insertion into a body cavity. In some embodiments, this step may also include fluidly coupling inlet and outlet channels  48 A,  48 B to pumps and heat exchangers, and electrically coupling cables from illumination devices  42 A,  42 B, imaging device  38 , and transducer  44  to control devices. These control devices may include visual monitors electrically coupled to imaging device  38 , and power supplies electrically coupled to illumination devices  42 A,  42 B, and transducer  44 . The power supply coupled to transducer  44  may be configured to direct an electric current at RF frequency to transducer  44 . 
     The distal end  22  of endoscope  20  may be inserted into the mouth of the patient and pushed down the body of the patient through the esophagus  14  (step  120 ). The illumination devices  42 A,  42 B and imaging device  38  may be activated, and the endoscope  20  inserted into the body guided by the image of the body cavity obtained by the imaging device  38 . The image may help identify an ulcer  18  or a ruptured blood vessel within the body (step  130 ). In some embodiments, coolant flow through the endoscope  20  may now be initiated (step  140 ) and regulated to control the flexibility of the endoscope  20  during insertion. To reduce the stiffness of elongate member  26  as the endoscope  20  traverses through tortuous body cavities, coolant may be evacuated from endoscope  20 . In cases where an increased rigidity of endoscope  20  is desired (for example, to push through an anatomical stricture in a body cavity), a controlled amount of coolant may be circulated through the endoscope  20 . Increasing the amount of coolant in endoscope  20  may increase the rigidity of endoscope  20 . In some embodiments, a thermoelectric module may be used instead of or in conjunction with the coolant. Guided by the image from imaging device  38 , end face  36  of end effector  24  may be positioned in stomach  12  such that a distal end  22  of endoscope  20  may be positioned proximate ulcer  18  on stomach wall  16 . 
     The endoscope  20  may be further pushed into the body so that the front-side  44 A of transducer  44  may be pressed against ulcer  18  (step  150 ). With the transducer  44  firmly pressed against ulcer  18 , the transducer  44  may be activated to induce a mechanical vibration on transducer  44  (step  160 ). The mechanical vibration of transducer  44 , as the transducer is pressed against ulcer  18 , may penetrate and heat up the tissue surrounding ulcer  18 . The heat and the pressure of transducer  44  against the tissue may locally fuse the blood vessels surrounding ulcer  18  together, thereby sealing ruptured blood vessels, and stopping the bleeding (step  170 ). 
     As the tissue heats up, the coolant flow through the end effector may remove excess heat produced by the vibration of transducer  44  against body tissue, to prevent charring of the body tissue. The coolant in reservoir  46  may get heated due to the heat conducted from the back-side  44 B of transducer  44 . The hot coolant may be directed towards the proximal end  28  of endoscope  20  through outlet channel  48 B. At the proximal end  28 , outlet channel  48 B may be fluidly coupled to a heat exchanger to dissipate the heat of the coolant. The cooled coolant may then be pumped back to reservoir  46  through inlet channel  48 A, using a pump fluidly coupled to the circuit. The flow of coolant through reservoir  46  may thus cool transducer  44  and prevent excessive heating of transducer  44  and the tissue. The amount of coolant circulated through the endoscope  20  may be controlled to maintain a desired temperature of transducer  44 . 
     After the ruptured blood vessels of ulcer  18  have been fused together, the front-side  44 A of transducer  44  may be backed off of ulcer  18 , and the endoscope  20  slowly retracted from the body of the patient (step  180 ). Although  FIG. 4  illustrate the steps being performed one after the other in a serial manner, in some embodiments, the order of steps may be different, and some or all of these steps may be performed in parallel. For instance, in some embodiments, the transducer  44  may be activated (step  160 ) before front-side  44 A of the transducer  44  is pressed against the ulcer (step  150 ). In some other embodiments, coolant flow may be initiated (step  140 ) along with activation of the transducer (step  160 ) and pressing of the transducer  44  against the ulcer  18  (step  150 ). 
     As indicated earlier, although an embodiment of the invention of the current disclosure is illustrated and described as being applied to an endoscope configured for hemostasis of a peptic ulcer, the invention may be broadly applied to any endoscopic or other suitable medical device. For instance, in some embodiments, a transducer  44  that vibrates in response to an electric current or other energy (such as, for example, laser energy) may be constructed as an add-on device. This add-on device may be coupled to the distal end of any catheter or like medical device to apply heat to an area to aid in any medical procedure. For example, transducer  44  may be used to deliver controlled focused heating to an area to aid in tissue ablation, activate/melt tissue devices such as fastening devices, disease treatment, etc. For instance, in the case of a biliary stricture, transducer  44  may be coupled (or embedded) in a distal tip of a duodenoscope, in the case of a colonic or esophageal stricture, transducer  44  may be coupled to the distal tip of a colonoscope or a gastroscope, respectively. Activation of transducer  44  may vibrate the distal tip of the catheter, endoscope, or other device as it tries to traverse a lesion in the body cavity. Such a device may also include a coolant being circulated past the transducer to remove the heat produced by the transducer. Vibration of the distal tip of the device may enable the device to more easily traverse the constricted body cavity proximate the lesion with minimal trauma to body tissue, thereby improving the procedural outcome and reducing the time needed to perform the procedure. In some embodiments, one or more transducers may also be coupled in different orientations (transversely, laterally, different angles, etc.) at a distal end of the endoscope to enable the endoscope to traverse constricted body cavities. 
     In another embodiment, a transducer  44  coupled to a transluminal device, such as an endoscope or a catheter, may be used as a mixing or a curing tool for injected or sprayed components. As a mixing tool, a two-part adhesive, delivered to a work site within the body, may be mixed by vibrating the mixture with transducer  44 . As a curing tool, a patch attached over a puncture using a heat curable adhesive may be cured by pressing a vibrating transducer over the patch. The combination of the pressure and the heat produced by the vibrating transducer may assist in the curing of the adhesive. 
     Conventional endoscopes are expensive reusable devices. Most conventional endoscopes include an imaging system (fiber-optic imaging bundle, fiber-optic illumination, etc.), which may account for most of the cost of the endoscope, and one or more working channels. In these conventional endoscopes, the imaging system and working channels may also take most of the room within the body of the endoscope and the front plane of the distal tip. In an embodiment of the endoscope of the current disclosure, the endoscope may be a disposable device that may include an inexpensive CMOS chip instead of the more expensive imaging fiber-optic bundle, and may include an ultrasound transducer as part of the endoscope. In some embodiments, such an endoscope may also not have any working channels and may be dedicated for the hemostasis procedure. In some embodiments, an endoscope of the current disclosure may be used for imaging in addition to the traditional means. In some embodiments of the current disclosure, an ultrasound transducer may be provided on a catheter which may be delivered through a working channel of a conventional endoscope. 
     The embodiments described herein are exemplary only, and it will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed systems and processes without departing from the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the invention being indicated by the following claims.