Abstract:
An illuminator film system may include one or more pre-cut sections of optical film applied to a waveguide to allow light to exit the waveguide through the film in a predetermined manner. The one or more pre-cut sections may be removed and reapplied during a procedure to redirect the light. A laminated illuminator film may be provided that uses a laminated optical film structure to direct light from a fiber optic input. Such a laminated illuminator film may be very low profile, low cost and easy to apply to a retractor for providing illumination during a surgical procedure.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 12/750,581 (Attorney Docket No. 40556-712.301, now U.S. Pat. No. ______), filed Mar. 30, 2010, which is a continuation of U.S. patent application Ser. No. 11/818,090 (Attorney Docket No. 40556-712.201, now U.S. Pat. No. 7,686,492), filed Jun. 12, 2007, which claims priority from U.S. Provisional Patent Application No. 60/813,391 (Attorney Docket No. 40556-712.101) filed Jun. 13, 2006, the full disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The inventions described below relate to the field of medicine and more specifically, to providing body cavity illumination for use in medical, dental and veterinary procedures. 
         [0004]    2. Background of the Invention 
         [0005]    Existing technology for illumination during surgical/medical procedures is often limited to overhead illumination. This illumination comes from either overhead lighting or head mounted fiber optic systems. Traditional overhead lighting systems face numerous limitations. Direct exposure of the field from the overhead source is required. Changes in patient or surgeon positioning requires repositioning of the light source. Frequent adjustments provide an inconvenience for the surgeon and disrupt the surgical flow. For deeper cavities, overhead systems provide poor quality illumination. Positioning of the surgeon, or the instruments may shield the overhead lighting and prevent illumination from reaching the field of the procedure. 
         [0006]    Head mounted fiber optic systems are used frequently for more limited surgical exposures, however, these devices also have numerous drawbacks. First, the surgeon is tethered by the light cord attached to the headset, limiting mobility in the operating room. Second, the devices are associated with head and neck fatigue with frequent or more prolonged use. Third, the devices require the surgeon to maintain a steady head and neck position to provide a constant and steady illumination of the field. Fourth, the use of remote light sources and fiber bundles introduces tremendous inefficiencies into the system. A six-foot fiber optic cable may lose 65% of the incoming light from a light source. The headlamp optical components may lose another 60% of the light from the fiber optic cable. In addition, surgeons using head mounted systems frequently complain of the heat generated by such systems. 
         [0007]    In addition, both headlamp and overhead systems provide inadequate illumination when used with less invasive surgical procedures with a limited incision to access a deeper or broader surgical cavity. For these cases, both overhead and headlamp systems only illuminate a fraction of the volume of the surgical space. 
         [0008]    The introduction of minimally invasive surgical techniques, has raised the demand for delivery of high intensity light through minimal surgical incisions into deep surgical fields. To address this demand, light delivery devices have been developed for delivery of light from remote, high intensity light sources to the surgical field. These devices generally consist of bundles of optical fibers that are integrated with or directly adhere to surgical retractors to illuminate the field and are connected via fiber optic cable to a high intensity light source. While these devices provide a way to illuminate the surgical field, they provide highly inefficient illumination. The small bundle diameter is susceptible to being completely blocked by any surgical debris or splatter such as blood or tissue, thereby requiring constant cleaning to maintain illumination. In addition, due to the limited divergence angle and highly Gaussian intensity profile, these devices only provide a small spot of light that requires constant repositioning to view the entire surgical area. In addition, these fiber optic light pipes are very expensive to manufacture, requiring significant amounts of expensive human labor. 
         [0009]    Waveguide illuminators are known in the art and typically allow light to exit the illuminator by using optical structures molded into the surface of the waveguide itself. Light injected into such waveguides is typically contained in the waveguide through total internal reflection. When the light strikes the optical structures, the reflection angle is interrupted such that the light now refracts out of the waveguide. Such systems may be useful for illumination of deep tissues, but often require the use of expensive, specialized tooling or manufacturing processes. Moreover, these waveguides are rigid and must be designed to fit particular instruments so different waveguides must be available to accommodate the variety of surgical instruments used in a given surgical procedure. 
         [0010]    Still other applications may involve woven fiber optic strands or fiber optic strands cut at various lengths to generate diffuse lighting. Light escapes the fiber either through a nick in the surface of the fiber or because a material has been applied to the surface of the fiber that disrupts total internal reflection, or the light merely escapes out of the cut ends of the fiber. This type of diffuse illumination is typically not suitable for illumination of deep tissues because it provides an insufficient level of illumination for tissues of interest and often shines light back into the surgeon&#39;s eyes, making viewing of the tissues difficult. Such systems are also expensive to manufacture. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    Light in medical applications may be used for illumination, diagnostic or therapeutic purposes. While this disclosure discusses primarily illumination applications, diagnostic and therapeutic applications are understood to be included as well. 
         [0012]    A film illumination system may include one or more pre-cut sections of optical film applied to a waveguide to allow light to exit the waveguide through the film in a predetermined manner. The one or more pre-cut sections may be removed and reapplied during a procedure to redirect the light. A laminated illuminator film may be provided that uses a laminated optical film structure to direct light from a fiber optic input. Such a laminated illuminator film may be very low profile, low cost and easy to apply to a retractor for providing illumination during a surgical procedure. 
         [0013]    In an illumination technique according to the present disclosure, a small, pre-shaped section of film is applied to the surface of a waveguide to allow light to exit the waveguide in a predetermined manner substantially only from the area to which the pre-shaped section of film is applied. Said pre-shaped section of film becomes a simple, stick-on illuminator film when applied to the waveguide or light guide. This pre-shaped section of film should have an area that is significantly smaller than the surface area of the waveguide or light guide on to which the pre-shaped or pre-cut section has been placed. 
         [0014]    A film illumination system according to the present disclosure may comprise one or more pre-cut sections of optical film, the pre-cut film sections including optical structures, for example, prismatic structures, for directing or focusing or diffusing light entering one side of the film as it exits the opposite side of the film. Said pre-cut section may also include one or more tabs for handling the pre-cut section and for removeably placing the pre-cut section on to a plastic waveguide. Pre-cut optical film sections may also include an adhesive layer for adhering to the waveguide. The composition of the adhesive layer may be selected to provide a refractive index specifically designed to enhance the leakage of light from the waveguide especially if the indices of the optical film layer and the waveguide are similar. 
         [0015]    Tabs may be color coded for the type of light directing function such as for example, diffuse, direction, focused, etc. The tab may also be used to show the directionality of a directional film. The waveguide may receive light from any suitable light source and may control and contain the light inside of the waveguide through total internal reflection. The waveguide may have polished surfaces and/or coated surfaces to promote internal reflection. 
         [0016]    A user may apply a pre-cut section or stick-on illuminator film to the waveguide to allow light to exit the waveguide. The stick-on illuminator film may also be removed and reapplied to a different part of the waveguide and/or in a different orientation to direct light as desired. Multiple pre-cut sections may be applied to the same waveguide to create a desired illumination area. 
         [0017]    For example, the waveguide or light guide may be a retractor made from a suitable light guiding material (e.g., acrylic, polycarbonate, silicone, glass, etc., that may be transparent or translucent) with a width greater than its thickness and a front surface that faces the surgical area. The light guide or waveguide may be a surgical instrument or may be attached to a surgical instrument. Two generally diffusing pre-cut sections may be placed near the lateral edges of the retractor up a desired distance from its tip to provide generally diffuse illumination of the surgical area, and a third pre-cut section may be placed between the first two pre-cut sections, said third pre-cut section providing a directional beam of light to illuminate a particular portion of the surgical area. The surgeon may perform some work, then move or rotate the directional pre-cut section to better illuminate another portion of the surgical area while keeping the other two diffuse precut sections in place. At the end of the procedure, the pre-cut sections may be removed from the plastic waveguide and discarded while the waveguide may be sterilized and reused. Damaged or occluded film sections may simply be removed and replaced. The user may employ any combination of stick-on illuminator films to achieve desired illumination. Pre-cut sections of a stick-on illuminator film may be provided at extremely low cost. 
         [0018]    Alternatively, a laminated film illumination assembly may be formed from an optical fiber having a suitable connector end for attaching to light source or light guide cable and a free end that is laminated with at least two layers of optical film. The optical fiber may be supplied as a mono-fiber or as a bundle of optical fibers. In a preferred orientation, the optical fibers are placed at one of the narrow ends of a rectangular shaped laminate structure with enough of the free optical fibers held in the laminate structure to hold the fibers securely and reduce the likelihood that the fibers can be pulled out during normal use. Preferably, the bottom layer of the laminate structure has an inside surface that is reflective or that has optical structures that serve to reflect light toward the top layer. The bottom layer also has a suitable adhesive on the outside surface for attaching the assembly to a surgical instrument, for example, a retractor. The upper layer preferably incorporates optical structures that serve to diffuse, shape, focus and/or direct light coming into that layer. The space between the upper and lower films is preferably occupied by an air layer, but an intermediate light guide layer, e.g., a suitably thick acrylic film or a thin molded polycarbonate or silicone piece, may occupy this space to promote total internal reflection or the two films may be adhered together thereby eliminating any substantial air space wherein an adhesive may promote internal reflection. The laminated film section may be made to be more or less flexible by employing such materials, or the film may be treated or structured to promote or restrict flexibility. Another protective transparent film may be placed on the upper film to protect the optical structures. Light exits the free optical fibers at one end of the laminate structure, travels along the laminate structure and is eventually reflected off of the lower layer and through the upper layer where it is directed as desired to illuminate tissue for surgical, diagnostic or therapeutic purposes. The user merely attaches a light source, e.g., a fiber optic light guide cable connected to a xenon, halogen or LED light source, to the connector end, peels a release liner from the adhesive on the bottom layer and attaches the assembly to a surgical instrument, e.g., a metal retractor. At the end of the procedure, the user may discard the assembly because of its low cost. A laminated illuminator film may be made very thin due to the thinness of the optical fibers and films of which it is made. A thin illuminator may be attached to a retractor and not take up valuable space needed to perform the surgery. It may be made in different sizes, thereby making the illuminator suitable for many types of surgical instruments and many types of surgeries. For example, a flat rectangular shape may be suitable for flat instruments such as a retractor blade. Alternatively, the flat film laminate may be formed as a cylinder, e.g., by attaching the two ends of the rectangular shaped film laminate, to slip over a round instrument such as nerve root retractor. Other instrument geometries may be accommodated by suitably shaping the film laminate. Furthermore, because the material is very inexpensive and the assembly process can be substantially automated, a laminated illuminator film may be very inexpensive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a surgical illumination system employing a pre-cut optical illuminator film. 
           [0020]      FIG. 2  is a perspective view of an alternate illuminator using pre-cut, stick-on film. 
           [0021]      FIG. 3  is a close up view of pre-cut illuminator films with directional beams. 
           [0022]      FIG. 4  is a close up view of pre-cut illuminator film with a combination diffuse and directional beam. 
           [0023]      FIG. 5  is a cross-section of an optical fiber termination formed from optical films. 
           [0024]      FIG. 5   a  is a cross-section of an alternative optical fiber termination formed from optical films. 
           [0025]      FIG. 6  is a cross-section of an optical fiber termination formed from optical films with an air gap. 
           [0026]      FIG. 6   a  is a cross-section of an alternative optical fiber termination formed from optical films with an air gap. 
           [0027]      FIG. 7  is a cross-section of an optical fiber termination formed from optical films with a light guide section. 
           [0028]      FIG. 8  is a perspective view of an illuminator assembly using a fiber optic ribbon cable and optical films. 
           [0029]      FIG. 9  is a perspective view of an optical film illumination assembly on a surgical retractor. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Surgical illumination system  10  of  FIG. 1  includes surgical retractor  12  with handle  12 H, waveguide  14  and fiber optic light guide cable  16 , which is attached to any suitable light source. Waveguide  14  functions to receive and conduct light from light guide cable  16  and the waveguide contains the light through total internal reflection. Without any surface interruptions, light energy contained in the waveguide would stay contained in the waveguide, subject to minor absorption, refraction and other losses as they occur over time. Stick-on illuminator film  17  is made from an optical film that changes the refractive index of the area of waveguide  14  to which the film is attached. Stick-on illuminator film  17  is provided with tab  18  to facilitate handling of the illuminator film. When stick-on illuminator film  17  is attached to waveguide  14 , directional light  20  is allowed to escape and illuminate a surgical area of interest. 
         [0031]    Waveguide  14  may be connected to an external light source, such as a xenon light source through fiber optic light guide cable  16 , or it may have an integrated light source, such as an integrated LED including drive electronics and battery. Alternatively, waveguide  14  may be attached to a portable light source, such as a portable LED light source. 
         [0032]    The shape of stick-on illuminator  17  may be any suitable shape and the shape geometry may be determined, at least in part, by the desired illumination target. For example, a circular precut section may be more suitable for a round illumination target and a rectangular precut section may be suitable for a wide angle illumination target. Such suitable illumination target geometries may be combined to create a combined illumination target. For example, a precut section may include a rectangular portion for providing a percentage of the available light for wide angle illumination and a circular portion for providing a percentage of the available light for spot illumination. 
         [0033]    In an alternative configuration, waveguide retractor  22  of  FIG. 2  serves as the mechanical retractor and the light waveguide and is attached to any suitable light source through fiber optic light guide cable  23 . In this configuration, stick-on illuminator film  24  is not provided with a tab, and it also provides diffuse illumination  26  that may be suitable for illuminating a larger surgical area than stick-on illuminator film  17  of  FIG. 1 . In this instance, illumination  26  may be hemispherical, but it may be preferred to reduce the amount of light be reflected back up into a surgeon&#39;s eyes. Waveguide retractor  22  may be a rigid device formed of any suitable material, e.g., molded polycarbonate or acrylic, or may be a flexible device, e.g., molded silicone. Waveguide retractor  22  may be in any suitable shape, e.g., bar, tube, etc. and includes handle  22 H. 
         [0034]      FIG. 3  provides a close-up view of surgical illuminator  28  showing distal end  29  of waveguide  30 . Directional stick-on illuminator films  32  and  34  are shown with respective tabs  33  and  35  that also mark the direction of the respective directed light output  32 L and  34 L, i.e., the light output is in the direction opposite of the tabs. Tab  33  of stick-on illuminator film  32  is pointed to the right, indicating that the direction of illumination output  32 L is to the left to illuminate area of interest  36  that is to the left of waveguide  30 . Tab  35  of stick-on illuminator film  34  is pointed to the left, indicating that the direction of illumination output  34 L is to the right to illuminate a particular area of interest  37  that is to the right of waveguide  30 . 
         [0035]    Referring now to  FIG. 4 , combination pre-cut illuminator film  38  incorporates diffuse and focused illumination features. Pre-cut, stick-on film element  38  is attached to a light conducting waveguide such as waveguide  40 . Stick-on film element  38  has a diffuse light output portion  42  that creates diffuse light  43  to illuminate a general surgical area and has a directed light output portion  44  that creates directed light  45  that illuminates a specific surgical area such as area  46 . Pre-cut, stick-on film element  38  is fabricated using standard film converting techniques. Again, the user positions the waveguide, then applies the stick-on illuminator film, or the illuminator film may be pre-applied to the waveguide before positioning the waveguide into the surgical field. The diffuse output portion may be designed to provide any pattern of diffuse light, e.g., lambertian, planar, curved, etc. The directed output portion may be designed to provide any pattern of directed light, e.g., circular, polygonal, etc. The diffuse output portion may even be constructed using two or more directional optical films providing two or more directional illumination outputs, e.g., a circular spot of light to the right of the waveguide midline and a square spot of light to the left of the waveguide midline. 
         [0036]    Optical termination  48  of  FIG. 5  is formed of laminated optical film elements such as film elements  49  and  50  at the end of any suitable light guide such as fiber optic cable  52 . Optical film  49  is illustrated as the lower portion with adhesive layer  53  and preferably serves a reflective function sending light to the upper portion. Optical film  50  is the transmissive upper portion with adhesive layer  55  and may operate in a focused light directing function or a light diffusing mode or both. In this configuration, adhesive layers  53  and  55  are thick enough and have sufficient optical clarity to allow light from fiber  52 , which may be a fiber bundle or a fiber ribbon cable or other suitable arrangement of fibers, to propagate at least partially along the adhesive layers so that light exits substantially along output surface  54  of optical film  50  that extends beyond fiber  52 . 
         [0037]    If the adhesive layers are not so configured, then the film layers may be shortened as shown in  FIG. 5A , showing alternative cable illuminator  58  which includes light cable  60 , upper light directing film  62  and lower light reflecting film  64 . Light exiting light cable  60  encounters lower reflecting film  64 , causing the light to be directed toward upper light directing film  62 , which may be configured to deliver diffuse light such as light  65 , directed light such as light  66  or some combination thereof. Depending on the thickness of upper light directing film  62 , the distribution of the light angles from light cable  60  and the paths that light rays take within the film laminate, some light may shine out the end of illuminator  58  and may actually shine downward direction past lower light reflecting film  64 . 
         [0038]    In an alternative configuration, lower light reflecting film  64  may be replaced with another piece of upper light directing film  62  to convert the highly Gaussian distributed light from light cable  60  to a more diffuse distribution that may be more useful in a diagnostic or therapeutic application or in an application where light shining in more than one direction is desired. 
         [0039]    Referring now to  FIG. 6 , laminated optical termination  68  is configured to engage any suitable light input structure such as an optical fiber bundle or a single core optical fiber or a length of polycarbonate, acrylic, silicone or other suitable light-conducting material such as light conduit or cable  70 . Light reflecting film  71  directs light from light cable  70  above to light output film  72 , which may provide diffuse illumination, directional illumination or a combination thereof. In this configuration, an air chamber such as air chamber  73  is created to allow all the light from light cable  70  above to be directed down the length of the optical film laminate structure created by joining films  71  above and  72  above along their edges. Films  71  above and  72  above are preferably cut in a rectangular shape, but may also be cut in any other suitable shape. 
         [0040]    As shown in  FIG. 6A , air chamber  74  of laminated optical termination  76  may be supported by a frame such as frame  77  made of a suitable material, e.g., plastic or metal, to help keep the air chamber open during use. Directing film  78  and reflecting film  79  perform the same function as the respective films in  FIG. 6 . Frame  77  may have a reflective surface at end  77 E opposite of the light input from input cable  80  or may have a layer of reflective film  81  to help ensure that light only exits directing film  78 . 
         [0041]    Referring now to  FIG. 7 , laminated film terminator  82  is sized to engage light input cable  84 , which is preferably a fiber optic ribbon with the fibers generally planar in a side by side orientation. The ends of the fibers, ends  86 , contact waveguide  88 , which propagates light along the length  82 L of the laminate structure. Reflecting film  89  serves to direct light toward output film  87 . Termination waveguide  88  may be fabricated from any suitable optical material such as polycarbonate, acrylic or silicone or another layer of optical film. In this configuration, the thickness of termination waveguide  88  is at least the same thickness as light input cable  84  to help ensure that all light from light input cable  84  enters termination waveguide  88 . Termination waveguide  88  may also incorporate optical structures, e.g., that are molded in or created via a hot stamp process that may help direct the light from light input cable  84  out to a surgical area to be illuminated. 
         [0042]    Alternatively, a laminated film termination such as termination  90  of  FIG. 8  engages a suitable light input element, for example, a fiber optic ribbon cable such as ribbon cable  92 . Output or top film  93  and reflective or bottom film  94  are adhered together along terminator edges  90 E. In this configuration, fiber optic ribbon cable  92  may have fibers extending the entire length of the laminated termination. In this case, the light may escape individual fibers where each fiber contacts top film  93  and/or bottom film  94 , or the fibers may be nicked or otherwise treated to allow light to escape the fibers directly without the need to contact either the top film or the bottom film. Fiber optic ribbon cable  92  may be a bundle of fibers whose cut ends are arranged in a particular shape, e.g., the bundle may be round at the input connector and may be rectangular or some other shape at the film laminate end, it may be a ribbon cable where fibers are typically arranged side to side, or it may be a single core fiber. 
         [0043]    Laminated illuminator system  96  of  FIG. 9  includes laminated film termination  97  on light input cable  98  attached to a retractor such as retractor  99  having handle  99 H. Input connector  100  serves to connect the illuminator system to a source of light. Light input cable  98  conducts light from connector  100  to the film laminate structure  97 , which directs light  101  to a surgical area  102  to be illuminated. Adhesive may be provided along light input cable  98  and/or film laminate structure  97  for attaching the illuminator film assembly to retractor  99 . 
         [0044]    While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.