Abstract:
An autoclavable flexible fiberscope for remote visualization. A flexible fiberscope shaft including a number of flexible fiberoptic image-transmitting fibers is attached to a video coupler for connection to a video camera or other external video device. High-temperature materials of fabrication and high-temperature seals are provided to resist damage during autoclave sterilization.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No.: 60/163,592, filed Nov. 5, 1999, the entire scope and content of which application is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to medical devices and procedures, and more particularly to a flexible fiberscope or endoscope that is constructed to withstand sterilization by autoclaving. 
     2. Description of Related Art 
     Medical practitioners often utilize fiberoptic endoscopes (interchangeably referred to herein as “fiberscopes”, “endoscopes”, “arthroscopes”, “laparoscopes”, etc.) in the performance of a variety of medical procedures. For example, fiberscopes in various forms are utilized with human or animal patients in arthroscopic procedures, laparoscopic procedures, cardiology, and diagnosis and treatment within the epidural space. Fiberscopes typically comprise a bundle of glass or other optical image transmission fibers, and one or more lenses for collecting and focusing an image. Flexible and rigid fiberscopes are known. 
     For economic reasons, it is typically desirable to reuse a fiberscope for more than one procedure. During use, however, the fiberscope typically becomes contaminated and must be cleaned and sterilized prior to reuse. A preferred method of sterilization of surgical implements is by way of exposure to elevated temperatures in an autoclave. While autoclavable rigid fiberscopes are known, it has proven difficult to produce a flexible fiberscope capable of withstanding sterilization by autoclave. 
     Accordingly, it has been found desirable to provide a flexible fiberscope capable of withstanding repeated autoclave sterilization. It is to the provision of an autoclavable flexible fiberscope meeting this and other needs that the present invention is primarily directed. 
     SUMMARY OF THE INVENTION 
     The present invention provides an autoclavable flexible fiberscope for optical image transmission. The autoclavable flexible fiberscope of the present invention can be adapted to use with a variety of medical procedures. In example embodiments, the autoclavable flexible fiberscope of the present invention is adapted for insertion into a lumen of a delivery vehicle such as a steerable catheter. 
     In one aspect, the invention is a fiberscope including a lens, a fiberoptic imaging bundle having a proximal end and a distal end, and a heat-resistant retaining sleeve mechanically coupling the lens to the distal end of the fiberoptic imaging bundle. 
     In another aspect, the invention is a video coupler for a fiberscope. The video coupler includes a scope coupling for connection to a fiberscope, a lens assembly including at least one lens, and high-temperature sealing means for isolating the lens assembly from an external environment. 
     In yet another aspect, the invention is a fiberscope and video coupling system including a fiberscope having a lens, a flexible fiberoptic imaging bundle having a proximal end and a distal end, a heat-resistant retaining sleeve mechanically coupling the lens to the distal end of the fiberoptic imaging bundle, and a scope housing including a bore engaging the proximal end of the imaging bundle. The fiberscope also includes a video coupler having a scope coupling for connection to the scope housing, a lens assembly including at least one lens, and high-temperature sealing means for isolating the lens assembly from an external environment. 
    
    
     These and other features and advantages of the present invention are described herein with reference to example embodiments shown in the appended drawing figures. 
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 shows a side view, in partial cross-section, of a fiberscope according to a preferred form of the present invention. 
     FIG. 2 is a perspective view, in partial cutaway, of a distal tip segment of the fiberscope of FIG. 1, according to a preferred form of the present invention. 
     FIG. 3 is a cross-sectional side view of a scope housing and video coupler according to a preferred form of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawing figures, wherein like reference numerals represent like parts throughout, preferred forms of the present invention will now be described. FIGS. 1-3 depict various components of a fiberscope and video coupling system of the present invention. As will be better understood with reference to the disclosure herein, the materials of fabrication of the fiberscope and video coupling system of the present invention are selected to withstand the temperature, pressure, moisture and chemical effects of autoclave sterilization. The components of the fiberscope and video coupling system of the present invention are constructed to minimize or avoid detrimental effect by thermal expansion differential between adjacent components of dissimilar materials. 
     FIGS. 1 and 2 depict a fiberscope  10  according to a preferred form of the present invention. The fiberscope  10  preferably comprises a flexible fiberoptic imaging bundle  12 , comprising a plurality of optically-transmissive flexible glass fibers. The fiberoptic imaging bundle  12  is preferably capable of withstanding temperatures up to at least about 275° F.-302° F. The flexible fiberoptic imaging bundle  12  has a proximal end  14  and a distal end or tip  16 . 
     The distal end  16  is shown in greater detail in FIG. 2 according to a preferred form of the invention. The fiberscope  10  preferably further comprises an imaging lens  20 , formed of optical grade glass or high-temperature plastic. In preferred form, the lens  20  and imaging bundle  12  are coupled by mechanical means only. For example, in a particularly preferred embodiment of the invention, the lens  20  and the distal end  16  of the imaging bundle  12  are coupled by a heat-resistant retaining sleeve  22 . The retaining sleeve  22  preferably comprises a stainless steel sleeve housing adapted to surround and tightly engage the distal end  16  of the imaging bundle  12  and the lens  20  to securely couple the lens to the imaging bundle. 
     The fiberscope  10  of the present invention preferably further comprises a protective image bundle sheath  28  enclosing the lens  20 , the retaining sleeve  22 , and at least a portion of the imaging bundle  12 . In preferred form, the protective sheath  28  comprises a braided polyimide flexible sheathing material. The protective sheath  28  is preferably pulled over the entire length of the retaining sleeve  22  and the imaging bundle  12 , to totally encase the flexible shaft portion of the fiberscope  10 . The outer surface of the retaining sleeve  22  is preferably continuously glued to the inner diameter of the distal tip end of the protective sheathing  28 , using a high-temperature epoxy or other high-temperature adhesive sealant, to form a continuous seal therebetween. 
     The fiberscope  10  of the present invention preferably further comprises one or more light fibers  30  for transmitting light from an illumination source (unshown) to the distal end  16  of the fiberscope  10  for illumination of the target tissue or other object to be observed. The light fibers  30  preferably comprise flexible glass fiberoptic fibers. An outer protective sheath  32  preferably encases the light fibers  30  and the imaging bundle  12  and lens  20  assembly within the protective sheath  28 . The outer protective sheath  32  preferably comprises a temperature-resistant, braided polyimide flexible sleeve. A high-temperature epoxy or other sealant is preferably provided between the protective sheath  28  and the outer protective sheath  32  to form a continuous seal therebetween. 
     The fiberscope  10  of the present invention preferably further comprises one or more strain-relief sleeves  40  at the proximal end  14  of the imaging bundle  12 . Two strain-relief sleeves  40   a ,  40   b  are depicted in FIG.  1 . Inner strain relief  40   a  encases the proximal end  14  of the imaging bundle  12  and outer strain relief sleeve  40   b  encases at least a portion of the inner strain relief sleeve. The strain relief sleeve(s)  40  preferably comprise a segment of heat-shrinkable tubing. The segment(s) of heat-shrinkable tubing are positioned onto the proximal end  14  of the fiberoptic imaging bundle  12 , and an appropriate amount of heat is applied thereto, causing the tubing to shrink and tightly encase and engage the imaging bundle  12  and/or any inner strain relief sleeve(s). 
     The fiberscope  10  of the present invention preferably further comprises a scope housing  50  engaging the proximal end  14  of the imaging bundle  12 . The scope housing  50  preferably comprises a body formed of aluminum, Ultem™ (by G.E. Plastics Structured Products, of Pittsfield, Mass.), or other high-temperature, substantially rigid material. The scope housing  50  preferably defines a bore  52  extending substantially therethrough, generally along its central, longitudinal axis. The bore  52  preferably comprises internal threads or surface features adapted to securely engage the proximal end  14  of the flexible fiberoptic imaging bundle  12 . A high-temperature epoxy or other high-temperature adhesive preferably secures the proximal end  14  of the imaging bundle  12  within the bore  52  of the scope housing  50 . The proximal end  14  of the imaging bundle  12  preferably extends substantially entirely through the scope housing  50 , and most preferably extends slightly beyond the proximal end  54  of the scope housing  50 . The proximal end  14  of the imaging bundle  12  is preferably polished to produce a satisfactory image. 
     The scope housing  50  preferably further comprises a locking screw  56  threadedly engaged within a cooperating bore formed in the scope housing. The locking screw  56  provides a position adjustment and locking mechanism for axial positioning of the fiberscope  10  within a delivery vehicle such as a steerable catheter (unshown). The locking screw  56  preferably engages a slotted docking member of the delivery vehicle, whereby the fiberscope  10  is longitudinally positioned by sliding the locking screw  56  within the slotted docking member to a desired scope position, and the scope is locked in position by tightening the locking screw against the docking member. 
     The proximal end  54  of the scope housing  50  preferably comprises a generally cylindrical outer surface for coupling with a video coupler, described in greater detail below. One or more circumferential O-ring grooves  58  are preferably provided in the outer surface of the proximal end  54  of the scope housing  50 , and a high-temperature O-ring  60  is preferably installed within each O-ring groove. 
     The present invention preferably further comprises a video relay coupling or video coupler  80  for coupling the fiberscope to a video relay module (VRM), a video camera head, an eyepiece, and/or other external video device(s). The video coupler preferably comprises a quick-connect-and-release bayonet coupling for connection to the video device. The video coupler preferably further comprises a scope coupling for connection to the proximal end  54  of the scope housing  50 . The video coupler  80  preferably comprises a coupler body formed from aluminum, Ultem™, or other high-temperature-resistant material of construction. In a further preferred form, the scope coupling of the video coupler  80  comprises a generally cylindrical internal bore adapted to receive the proximal end  54  of the scope housing  50 . The O-ring(s)  60  mounted to the scope housing  50  sealingly engage the inner surface of the bore of the video coupler  80  to form a continuous seal therebetween. Most preferably, a double O-ring seal is provided, as seen best with reference to FIG.  3 . The video coupler  80  is preferably releasably coupled to the scope housing  50  by means of one or more set screws  82  or other retention means. 
     The video coupler  80  of the present invention preferably further comprises a lens assembly including at least one optical lens. In the depicted embodiment of FIG. 3, the video coupler  80  preferably comprises a first lens  90  and a second lens  92 . A series of spacers and retaining rings are preferably provided for securing the lenses in place within the video coupler  80 , as seen best with reference to FIG.  3 . 
     In preferred form, the video coupler  80  of the present invention preferably further comprises a high-temperature sealing means for isolating the lens assembly from the external environment. For example, the high-temperature sealing means isolates the more temperature-sensitive internal components of the lens assembly from the potentially damaging environment of the autoclave during autoclave sterilization. The high-temperature sealing means preferably comprises at least one high-temperature-resistant window, formed of a generally transparent, temperature-resistant material such as, for example, optical grade glass, fused silica, and/or borosilicate. The window  100  is preferably secured in place on the video coupler  80  by means of a window retainer  102 . A high temperature resistant O-ring  104  is preferably provided to form a heat-resistant seal between the window  100  and the outer body of the video coupler  80 , thereby isolating the lens assembly and other internal components of the video coupler  80  from the external environment. 
     The video coupler  80  preferably further comprises a camera adapter  110  for releasable connection to a video camera (unshown). A focus ring  112  and bearing ring  114  are preferably provided on the video coupler  80  for focusing the image transmitted thereby. As seen best with reference to FIG. 3, all interfaces between components of the video coupler are preferably continuously sealed by high-temperature O-rings and/or high temperature epoxy. 
     The fiberscope  10  and video coupler  80  preferably cooperate to form a fiberscope and video coupling system. The fiberscope and video coupling system of the present invention is assembled by mating the proximal end  54  of the scope housing  50  into the bore of the video coupler  80 . The components are preferably semi-permanently connected by means of a threaded connection therebetween. The O-ring(s)  60  seal the interface between the video coupler  80  and the scope housing  50  against the temperature, pressure, moisture, and chemical effects of autoclave sterilization. 
     While the invention has been described in its preferred forms, it will be readily apparent to those of ordinary skill in the art that many additions, modifications and deletions can be made thereto without departing from the spirit and scope of the invention.