Abstract:
A variable-view arthroscope or like instrument (endoscope, etc.) includes an elongated housing tube extending from an outer control end to an inner image input end that is closed by an input lens; the input lens preferably is a diverging lens. In the form shown in FIGS.  6 A- 6 C, the input lens has a concave inner surface and a concave outer surface. A lighting apparatus illuminates a surgical working area beyond the image end of the housing tube; the illumination may be projected outwardly through the input lens. A movable mirror intercepts light reflected from the surgical working area to produce a working image that is reflected to a fixed mirror that in turn reflects the working image to impinge upon the input end of a relay lens assembly. The working image is transmitted to a receptor, which is located near the outer (control) end of the housing tube. The relay lens applies the image to an image device, such as a conventional CCD unit, that transmits the image to a location exterior to the scope. A control member, shown as a control rod extending longitudinally within the housing tube, varies the position of the movable mirror between first and second limits, adding about 30° or more to the image available to a user of the instrument.

Description:
This application is a continuation of application Ser. No. 09/243,845 now U.S. Pat. No. 6,110,105, filed Feb. 3, 1999 which prior application is incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Arthroscopes and other like optical instruments, such as endoscopes, have long been known in the field of surgery and in other fields. In this specification and in the appended claims the term “arthroscope” means and should be interpreted to include an endoscope or any other like optical instrument, whether used for surgery or otherwise. In this application, the invention is described in connection with an instrument employed for surgery, as in human surgery. 
     Over the last fifteen or more years the nature of surgery has changed substantially, with minimally invasive surgery becoming a mainstay. Within the orthopedic community, in particular, arthroscopy and similar techniques have become the most common surgical procedures. Surgery using such techniques is less painful for the patient and, in most instances, can be performed more quickly and safely than with techniques that require greater invasion of the patient&#39;s body; anesthesia is also less complicated, the surgery can often be handled on an outpatient basis, and the procedures are better from the standpoint of cost effectiveness. Patients return to normal life more quickly, and hospital stays may be reduced in length or even eliminated. However, all of these benefits are available only if the minimally invasive surgery allows for better diagnostic capabilities, improved surgical techniques, and reduced iatrogenic damage. Similar benefits are available with other, non-surgical, instruments. 
     One problem in these minimally invasive techniques derives from limitations in the arthroscopes, endoscopes and other principal optical instruments employed. In particular, the rather limited field of view afforded by even the best instruments commercially available in 1998 has inhibited progress to at least some extent; available instruments and techniques have not changed dramatically since 1985. A substantial improvement in the field of view available to a person employing an arthroscope or like instrument for exploratory or repair procedures is much needed. 
     Several techniques for modification (widening) of the view offered by arthroscopic/endoscopic instruments have been proposed, but they have not been especially successful. Generally, such proposals have required packing a plurality of movable lenses or prisms into the input end of the instrument; the resulting problems of precision of construction, precision of relative movements, space requirements, optical distortions, and elimination of undesired “ambient” light have been substantial. This is not particularly surprising; interaction between the prisms and lenses involved, along with light loss, exacerbates the problem. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention, therefore, to provide a new and improved arthroscope that affords the user a broadened effective field of view with few or no added lenses or prisms, a minimum of movable parts, and no requirement for movement of the instrument to vary its scope of view. 
     A related object of the invention is to afford a new and improved arthroscope that is relatively simple and effective in construction, cost efficient and durable, yet has an improved and expanded field of view. 
     Accordingly, the invention relates to a variable view arthroscope comprising an elongated housing having an image input end spaced from an outer control end. An input lens, preferably a diverging type lens, closes (and usually seals) the image input end of the housing tube, which is beveled at an angle of 30° to 60°. Lighting means are provided for illuminating a working image area beyond the image input end of the housing tube. An input lens, located in the input end of the housing tube, intercepts light reflected back from the working area. That reflected light constitutes a working image. The light image reflected from the working area back through the input lens is directed to a movable mirror. The movable mirror may be rotatable or it may move linearly. There is a control member, usually an elongated control rod, for varying the position of the movable mirror to any position or to a series of fixed positions between a first limit position and a second limit position. A fixed mirror is positioned to intercept light from the movable mirror, re-directing that light toward a relay lens located near the fixed mirror position. A relay lens assembly directs the light image from the fixed mirror through the length of the relay lens assembly to impinge upon a focusing lens assembly. The focusing lens assembly consists of focusing and zoom lens and their controls and is preferably located in the control portion of the arthroscope. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a variable view arthroscope constructed in accordance with a preferred embodiment of the invention; 
     FIG. 2 is an elevation view of the instrument of FIG. 1; 
     FIG. 3 is a plan view, on an enlarged scale, of the control portion of the arthroscope of FIGS. 1 and 2; 
     FIG. 4 is an elevation view, on an enlarged scale, of the control portion of the instrument of FIGS. 1 and 2; 
     FIG. 5 is a detail view taken approximately as indicated by line  5 — 5  in FIG. 3; 
     FIG. 6A is a sectional, longitudinal elevation view, on an enlarged scale, of the image input end of the arthroscope of FIG. 1, adjusted for a maximum upward view; 
     FIG. 6B is a sectional elevation view, like FIG. 6A, of the image input end of the arthroscope of FIG. 1, adjusted for an intermediate view; 
     FIG. 6C is a sectional elevation view, like FIGS. 6A and 6B, of the image input end of the arthroscope of FIG. 1, adjusted for a maximum downward view; 
     FIG. 6D is a sectional view taken approximately along line  6 D— 6 D in FIG. 6A; 
     FIG. 7A is an elevation view, on an enlarged scale, of a slide member used in the arthroscope of FIG. 1; 
     FIG. 7B is a plan view of the slide of FIG. 7A; 
     FIG. 7C is an end view of the slide of FIGS. 7A and 7B; 
     FIG. 8A is a plan view, on an enlarged scale, of a cam/axle member used in the control end (FIG. 3) of the arthroscope of FIG. 1; 
     FIG. 8B is an end view of the cam/axle member of FIG. 8A; 
     FIG. 8C is an elevation view of the cam/axle member of FIG. 8A; 
     FIG. 9A is a plan view, on an enlarged scale, of two control knobs from the control end (FIG. 3) of the arthroscope of FIG. 1; 
     FIG. 9B is an end view of the control knobs of FIG. 9A; 
     FIG. 9C is a section view, taken approximately along line  9 C— 9 C in FIG. 9A, of the control knobs; 
     FIG. 10 is an elevation view, on an enlarged scale, of the lighting apparatus for the arthroscope of FIG. 1; 
     FIG. 11A is a longitudinal sectional elevation view, like FIG. 6A, of the input (viewing) end of an arthroscope comprising another embodiment of the invention, adjusted for a maximum upward view; 
     FIG. 11B is a sectional elevation view, like FIG. 11A, of the apparatus of FIG. 11A adjusted for an intermediate view; 
     FIG. 11C is a sectional elevation view, like FIG. 11A, adjusted for a maximum downward view; 
     FIG. 12A is a plan view of the slide and cam/axle member used in the control end (FIG. 3) of the arthroscope of FIG. 1 shown in a center position; 
     FIG. 12B is a cross-sectional view taken along line  12 B-D of FIG.  12 A and shown in a center position; 
     FIG. 12C is a cross-sectional view taken along line  12 B-D of FIG.  12 A and showing the slide in a moved position to the right of its position of FIG. 12A; and 
     FIG. 12D is a cross-sectional view taken along line  12 B-D of FIG.  12 A and showing the slide in a moved position of FIG.  12 A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One preferred embodiment of the invention is illustrated as an arthroscope  30 , shown in FIGS. 1-10. 
     As shown in FIGS. 1 and 2, arthroscope  30  includes an elongated housing tube  31 , which has an image input end  32  and a control end  33 . Housing tube  31 , and more specifically its control end  33 , may extend into the outer control portion  35  of arthroscope  30 , shown in greater detail in FIGS. 3-5. As shown in FIGS. 1-4, the control portion  35 , from which the control end  33  of the housing tube  31  of arthroscope  30  projects, ends with a CCD attachment  36 . The CCD attachment  36  is connected by appropriate means to an image screen (not shown) to be viewed by a person using arthroscope  30 . Because CCD attachment  36  may be of conventional construction and does not constitute a part of the present invention, it has not been shown in detail. 
     As best shown in FIG.  2  and in the enlarged views of FIGS. 6A-6C, the image input end  32  of housing tube  31  is of beveled construction at its extreme end; the bevel is usually between 30° and 60°. The outer end of housing tube  31 , shown in enlargement in FIGS. 6A-6C, is closed by a diverging input lens  37  (plural lenses may be used). Input lens  37  is shown as having an outer concave surface  38  spaced from an inner concave surface  39 . Input lens  37  is preferably sealed into the tip of the input end  32  of housing tube  31 ; a suitable seal material to mount lens  37  in place in the end of housing tube  31  is any conventional sealing adhesive approved by the FDA for in vivo use. Input lens (or lenses)  37  may be formed of optical glass or any other suitable lens material. When a single input lens is used, input lens  37  preferably has a rim matched as closely as possible to the inside diameter of the housing tube  31  at its image input end  32  to assure a good seal between the housing tube and the input lens. Similar expedients should be employed if plural input lenses are utilized. 
     Arthroscope  30  includes, an outer control portion  35  and a light source  41  that is connected to a lighting means or apparatus  42 ; see FIGS. 2 and 4. The lighting assembly  42  includes one or more optic fiber bundles  43 ; the fiber optic bundle (or bundles) extend to the input end of the arthroscope; see FIGS. 4 and 6D. The optic fiber bundles  43  have been omitted in FIGS. 6A-6C (and in other Figures) because they may be conventional in construction. The lighting assembly  42  is utilized to illuminate a surgical working area (not indicated) beyond the image input end  32  of the housing tube; illumination of the surgical working area may be made through the input lens  37 . 
     A control member, shown in FIG. 4 as a control rod  45 , extends longitudinally through the housing tube  31  from outer control portion  35  to its input end  32 . Rod  45  is used to vary the position of a slidably movable mirror (See arrows A in FIGS. 6A-6C) having a base  46  and a mirror surface  47  along the axis of rod  45 . Mirror surface  47  is shown as planar in the drawings, but the movable mirror may be concave or other shapes. The mirror surface  47  is aligned with but spaced from the inner surface  39  of input lens  37 . See FIGS. 6A-6C. The end of control rod  45  is affixed to the movable mirror base  46 , as best shown in the enlarged views of FIGS. 6A-6C. A suitable commercially available adhesive may be used to join the end of rod  45  to the base  46  of the movable mirror; alternatively, soldering or brazing may be used if desired. The tip of control rod  45  may be polished and coated to afford a suitable movable mirror, eliminating the need for a separate part  46 . 
     At the control end  35  of the arthroscope  30  the control rod  45  extends into and engages a slide  48 . Slide  48  is driven linearly by means of two control knobs  49  and  50 , as described hereinafter in connection with FIGS. 9A-9C. 
     In the arthroscope  30 , as best shown in FIGS. 6A-6C, the base  46  of the movable mirror  46 ,  47  slides linearly between a maximum upward view position (FIG.  6 A), through an intermediate position (FIG.  6 B), to a maximum downward view position (FIG.  6 C). Of course, the movement of the movable mirror base  46  may be reversed, moving from its maximum downward position (FIG. 6C) toward its maximum upward position (FIG.  6 A). The images that may be provided to a surgeon by the arthroscope  30  all overlap. The maximum upward view of FIG. 6A, with movable mirror  46 ,  47  advanced by control rod  45  to a position immediately adjacent input lens  37 , has an overlap of about fifty percent with the maximum downward view (FIG. 6C) afforded when the sliding mirror  46 ,  47  is fully retracted. 
     At the top of the input end of arthroscope  30 , as seen in FIGS. 6A-6C, there is a fixed mirror comprising a. base  51  and a reflective (mirror) surface  52 . The fixed mirror surface  52  intercepts a light image from the movable mirror surface  47  and re-directs that light image to impinge upon the input end  53 A of a relay lens assembly  53 . Relay lens assembly  53 , FIGS. 6A-6C, may be of conventional construction having an outer stainless sleeve  54  for stability and directs the light toward a receptor, shown as a focusing lens assembly  55  (FIGS. 1,  2 ,  3  and  4 ). The focusing lens assembly  55  consists of focusing and zoom lens and is of conventional design. The focusing lens assembly  55  directs the light image in the customary manner, into the CCD attachment  36 ; see FIGS. 14. A slide  48  is located in the control portion  35  of arthroscope  30 ; the slide, shown in FIGS. 7A-7C, comprises a main body  57  having an axial relay lens opening  58 , the relay lens opening  58  also extends through an enlarged end  59  of the slide. A socket  61  also in slide  48 , formed to align and attach control rod  45  to slide  48 , is best shown in FIG.  7 B. The control rod socket  61 , in the illustrated embodiment, is located directly below the axial opening  58  for the relay lens. 
     The cam portion  65  of cam/axle member  62  is positioned in a central transverse opening  63  in slide  48 ; see FIGS. 7A-7C for opening  63 , FIGS. 8A-8C for cam/axle member  62 . 
     Opening  63  is not quite circular in cross-section; it is enlarged or “stretched” slightly, as is most apparent in FIG.  7 B. The cam/axle member  62  includes a large control knob shaft attachment segment  64  of circular cross-section, cam segment  65  contains a relay lens assembly slot  66 , and a small control knob shaft attachment segment  67 . This preferred construction is shown in detail in FIGS. 8A-8C. Two control knobs, shown in FIGS. 9A-9C, are mounted on the outer ends  64  and  67  of cam/axle member  62  (FIGS.  8 A- 8 C). The. control knobs include a right-hand control knob  49  that is fitted onto the large control wheel shaft attachment segment  64  of the cam/axle member  62 . The second or left-hand control knob  50  fits onto the smaller control knob shaft attachment segment  67  of cam/axle member  62 . See FIGS. 8A-8C,  9 A- 9 C and  12 A- 12 D. 
     The control knobs  49  and  50  and their shaft attachments  64  and  67 , respectively, may be connected to each other by conventional means. Either of the control knobs  49  and  50  can be used to rotate cam  65  within slide opening  63 , thus causing slide  48  and the attached control rod  45 , to move linearly in relation to the rotational motion of cam/axle  62  through a distance  68  as shown in FIGS. 12C and 12D. FIG. 12C shows the slide  48  moved to a rearward position closest to the control end  33  of the housing tube  31 . FIG. 12D shows the slide  48  moved to a forward position closest to the image input end  32  of the housing tube  31 . 
     The lighting assembly  42 , illustrated in FIG.  2  and shown in greater detail in FIG. 10, may include a condenser lens  71  to focus light from a suitable source  41  onto one end  72  of the light bundles  43  that extend to the input end of the arthroscope  30 . See FIG.  6 D. Actually, there may be two or more fiber optic light bundles  43 ; to supply light to the input end of arthroscope  30 . As previously noted, the lighting assembly may be quite conventional in construction and hence has been described only generally. 
     Operation of the arthroscope  30 , (FIGS.  1 - 10 ), can now be considered. At the outset, light from source  41  (FIG. 2) is focused upon the end  72  of one or more fiber optic bundles  43 , as by an appropriate lens  71  (FIG.  10 ). As a consequence, a surgical working area just beyond the input end  32  of the arthroscope  30  (FIGS. 1 and 2) is illuminated. In arthroscope  30 , illumination is effected through input lens  37  (FIGS.  6 A- 6 C). Light from bundle(s)  43 , at least in part, reflects from the fixed mirror  51 ,  52  onto the reflective surface  47  of the movable mirror, and through the input lens  37  into the area to be illuminated. 
     A light image reflected from the surgical working area, after passing through input lens  37 , impinges on the inclined reflective surface  47  of the movable mirror  46 ,  47 . That light image is directed from the movable mirror surface  47  to impinge upon the reflective surface  52  of the fixed mirror  51 . From the fixed mirror the light image is re-directed toward the input end  53 A of the relay lens assembly  53 ; see FIGS. 6A-6D. The relay lens system  53  supplies the image to the CCD attachment. 36 , through focusing lens assembly  55 , to be viewed by the surgeon or other person using the arthroscope  30 . 
     If the person using arthroscope  30  is dissatisfied with the image available through the CCD attachment  36 , control knobs  49  and/or  50  may be used to vary the image. That is, the control knobs, through cam/axle member  62  (FIGS.  8 A- 8 C), slide  48  (FIGS.  7 A- 7 C), and rod  45  (FIGS. 6A-6C) can be used to advance the movable mirror  46 ,  47  toward the input lens  37  (see FIG.  6 A), or to retract the movable mirror from the input lens (see arrow A in FIGS. 6B and 6C) to a “lower” position. In this way the image supplied to the surgeon or other person using the instrument  30  can be and is varied to a substantial extent with no change in the position of the instrument. In effect, the overall viewing range of the instrument  30  is enhanced by at least thirty degrees with no need to reposition the instrument axially. Further correction of the image can be afforded by appropriate software. 
     FIGS. 11A,  11 B and  11 C afford sectional elevation views of the input end  132  of a modified instrument; thus, FIGS. 11A,  11 B and  11 C correspond to FIGS. 6A,  6 B and  6 C, respectively. In FIGS. 11A-11C, the reference numerals and illustrated elements correspond to those employed in FIGS. 6A-6C, except for those elements that have been modified. Thus, the instrument input end  132  of a housing tube  131  is beveled, as previously described, and is closed by an input lens  37 . The input lens  37  may have two concave lens surfaces, an outer surface  38  and an inner surface  39  as shown; other input lens structures may be used. A fixed mirror base  51  is mounted in the upper portion of housing tube  31 , immediately adjacent input lens  37 ; the fixed mirror base  51  has a reflective coating on its surface  52  that faces the input end  53 A of a relay lens assembly  53 . 
     In the modification shown in FIG. 11A, there is a pivotally movable mirror comprising a base  146  having a reflective surface  147 . The mirror base  146  is pivotally mounted on a shaft  148  that extends transversely of the instrument between the two sides  170  (only one shown) of a generally U-shaped support member  171  positioned in the lower part of housing tube  131 . The movable mirror base  146  is connected to the end of a control rod  145 , as by a pin  172 ; rod  145  is similar to rod  45 . The control rod  145  can be moved linearly as indicated by arrow B in FIGS. 11A, B and C. 
     The views of FIG.  11 B and FIG. 11C are the same as FIG. 11A except that FIG.  11 B shows the pivotally movable mirror  146 ,  147  at an intermediate position, for an intermediate image, and FIG. 11C shows the pivotally movable mirror  146 ,  147  positioned for a maximum “downward” view. It should be understood that FIGS. 11A-11C are assumed to be vertically oriented. They could equally well be horizontally oriented, as could FIGS. 6A-6C, so that references to “upward” and “downward” could equally well be modified to “right” and “left”, or vice versa. Because the control rod  145  acts as previously described for rod  45 , and because only the movable mirror has been changed, from linear movement to rotational movement, it is believed to be unnecessary to provide any further description, structural or operational, of the arrangement shown in FIGS. 11A-11C. 
     Several parts of instrument  30  can be changed from those illustrated without appreciable effect on overall operation of instrument  30 . For example, input lens  37 , the shape of the movable mirrors  46 ,  47  and  146 ,  147  and the illustrated relay lens assembly  53  can be changed, as can the lighting assembly  42 ,  43 . It will be recognized that the control rod  45  (or rod  145 ) may be modified; it constitutes a preferred mechanism for operating the movable mirror but any desired alternative that will move that mirror, whether linearly or along a pivotal or other required path, can be used. The angle of the level of the outer end of housing tube  31  may be varied as desired; a level of 30° to 60° is preferred, but may depend on the primary use for instrument  30 . It will be recognized that use of a CCD unit for a display is not essential. The “software” used for the display may vary appreciably. Any preferred technique to enable the instrument user to move the movable mirror over its operational range is acceptable.