Patent Publication Number: US-2021177540-A1

Title: Illuminated cannula

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application:
         a. is a continuation application of U.S. Non-Provisional patent application Ser. No. 16/248,037, filed Jan. 15, 2019, titled “Illuminated Cannula,” whose inventor is Niels Alexander Abt,   b. claims the benefit of priority of U.S. Provisional Application Ser. No. 62/626,325, filed Feb. 5, 2018, titled “Illuminated Cannula,” whose inventor is Niels Alexander Abt (U.S. Non-Provisional patent application Ser. No. 16/248,037 claimed the benefit of priority of U.S. Provisional Application Ser. No. 62/626,325), and   c. claims the benefit of priority of U.S. Provisional Application Ser. No. 62/713,190, filed Aug. 1, 2018, titled “Illuminated Cannula,” whose inventor is Niels Alexander Abt (U.S. Non-Provisional patent application Ser. No. 16/248,037 claimed the benefit of priority of U.S. Provisional Application Ser. No. 62/713,190).       

     All three applications (U.S. Non-Provisional patent application Ser. No. 16/248,037, U.S. Provisional Application Ser. No. 62/626,325, and U.S. Provisional Application Ser. No. 62/713,190) are hereby incorporated by reference in their entirety as though fully and completely set forth herein. 
    
    
     BACKGROUND 
     The human eye can suffer a number of maladies causing mild deterioration to complete loss of vision. While contact lenses and eyeglasses can compensate for some ailments, ophthalmic surgery is required for others. Generally, ophthalmic surgery is classified into posterior segment procedures, such as vitreoretinal surgery, and anterior segment procedures, such as cataract surgery. Vitreoretinal surgery may address many different eye conditions, including, but not limited to, macular degeneration, diabetic retinopathy, diabetic vitreous hemorrhage, macular hole, detached retina, epiretinal membrane, and cytomegalovirus retinities. 
     In vitreoretinal surgery, the surgeon needs to be able to see the posterior segment to properly address the eye condition. However, undesirable light, such as glare and/or glistening, from the surgical field may impact visibility of the posterior segment of the eye. Currently, vitreoretinal surgeons can work in a darkened operating room to decrease concerns with the undesired light. Alternatively, the operating room may not be darkened, but the vitreoretinal surgeon may then have difficulty visualizing the posterior segment due to the undesired light. Access to the posterior segment in vitreoretinal surgery can be provided by one or more cannulas inserted into the eye. 
     SUMMARY 
     In an exemplary aspect, the present disclosure is directed to an illuminated cannula system. The illuminated cannula system may include a cannula that includes a cannula hub at a proximal end of the cannula and a tube portion extending from the cannula hub towards a distal end of the cannula. The cannula hub may be operable to emit visible light. 
     In another exemplary aspect, the present disclosure is directed to a surgical system. The surgical system may include a surgical console, a microscope communicatively coupled to the surgical console, and a cannula operable to emit visible light. The cannula may include a cannula hub disposed at a proximal end of the cannula and a tube portion that extends from the cannula hub towards a distal end of the cannula. 
     In another exemplary aspect, the present disclosure is directed to a method for light projection. The method may include inserting a cannula into an eye; emitting visible light from at least one luminescent material disposed at a proximal end of the cannula; and disposing a surgical instrument through the cannula. 
     The different aspects may include one or more of the following features. The cannula may include a lumen extending a long a longitudinal axis of the cannula. A trocar having a shaft portion and a blade portion may also be included. The trocar may be configured to be receivable into the lumen such that the blade portion of the trocar extends distally from the tube portion of the cannula. The cannula hub may include at least one luminescent material selected from the group consisting of a fluorescent material, a phosphorescent material, a chemiluminescent material, and a radioluminescent material. The at least one luminescent material may be disposed in the cannula hub, and the cannula hub may include a material that is transparent or translucent. The at least one luminescent material may be disposed in a coating that is deposited on the cannula hub. The cannula hub may include a container including a radioluminescent material and a fluorescent material, the radioluminescent material being operable to release electrons that interact with the fluorescent material to generate the visible light. The cannula hub may include a luminescent container disposed at the proximal end of the cannula. The luminescent container may include a first reactant and a second reactant. The second reactant may be disposed in an interior container disposed within the luminescent container. The interior container may separate the second reactant from the first reactant, and the first reactant and the second reactant are operable to react to emit the visible light when the first reactant and the second reactant are combined. 
     The cannula may include a lumen extending along a longitudinal axis of the cannula. A trocar may be received within the lumen of the cannula. The trocar may include a shaft portion and a blade portion. The trocar may extend through the lumen such that the blade portion extends distally from the tube portion of the cannula. The shaft portion of the trocar may include a shoulder portion that is engageable with the luminescent container extending into the lumen. The visible light may be provided to the cannula hub through an optical fiber. 
     The different aspects may also include one or more of the following features. The cannula may include a container disposed in the cannula hub. The container may include a radioluminescent material and a fluorescent material, the radioluminescent material being operable to release electrons that interact with the fluorescent material to generate the visible light. The cannula may include a luminescent container disposed in the cannula hub and an interior container. The interior container may be disposed within the luminescent container. A first reactant may be contained within the luminescent container, and a second reactant may be disposed in the interior container. The interior container may separate the second reactant from the first reactant, the first reactant and the second reactant being operable to react to emit the visible light. An ultraviolet light source may be operable to emit ultraviolet light at the cannula. The cannula hub may include a fluorescent material that emits the visible light in response to the ultraviolet light. A light source and an optical fiber coupled to the cannula and the light source may also be included. The optical fiber may be operable to carry the visible light form the light source to the cannula. Ultraviolet light may be directed at the proximal end of the cannula to cause the at least one luminescent material to emit the visible light. The at least one luminescent material may include a fluorescent material. The optical fiber may include a modification. The modification may cause a portion of light passing through the optical fiber to be transmitted through the modification and into the cannula hub. Emitting visible light from at least one luminescent material disposed in a proximal end of the cannula may include activating a luminescent container by removal of a trocar from the cannula. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These drawings illustrate certain aspects of some of the implementations of the present disclosure and should not be used to limit or define the scope of the disclosure. 
         FIG. 1  illustrates an example surgical system that includes a cannula with illumination. 
         FIG. 2  illustrates an example surgical system that includes a cannula with illumination, wherein the cannula includes a luminescent material. 
         FIG. 3  illustrates another example cannula with illumination, wherein the cannula includes a luminescent material. 
         FIG. 4  illustrates another example cannula with illumination, wherein the cannula includes a luminescent material. 
         FIG. 5  illustrates another example of a cannula with illumination, wherein the cannula includes a luminescent material. 
         FIG. 6  illustrates another example of a cannula with illumination, wherein the cannula includes chemiluminescent materials. 
         FIG. 7  illustrates an example of a luminescent container that holds chemiluminescent materials. 
         FIG. 8  illustrates a further example of a cannula with illumination, wherein the cannula includes a luminescent container including chemiluminescent materials, and also shows the corresponding trocar operable to interact with the luminescent container. 
         FIG. 9  illustrates an example of a trocar that interacts with the luminescent container holding the chemiluminescent materials. 
         FIG. 10  illustrates another example of a cannula with illumination, wherein the cannula includes chemiluminescent materials. 
         FIG. 11  illustrates another example cannula with illumination, wherein light is provided to the cannula with an optical fiber. 
         FIG. 12  illustrates another example cannula with illumination, wherein light is provided to the cannula with an optical fiber. 
         FIGS. 13A and 13B  illustrate embodiment further example of a cannula with illumination, wherein light is provided to the cannula with an optical fiber and a separate optical fiber provides light in the eye. 
         FIG. 14  illustrates another example of a cannula with illumination, wherein light is provided to the cannula and into the eye with an optical fiber. 
         FIG. 15  is enlarged detail view of the optical fiber shown on  FIG. 14 . 
         FIG. 16  illustrates another example of a cannula with illumination, wherein light is provided to the cannula with an optical fiber and a separate optical fiber provides light in the eye. 
         FIG. 17  illustrates another example of a cannula with illumination, wherein a surgical instrument includes a light to illuminate a cannula. 
         FIG. 18  illustrates another example of a cannula with illumination, wherein a surgical instrument includes a light to illuminate a cannula. 
         FIG. 19  is an example method of providing a cannula for use in a surgical procedure, the cannula being operable to emit visible light. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the implementations illustrated in the drawings and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with reference to one or more implementations may be combined with the features, components, and/or steps described with reference to other implementations of the present disclosure. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts. 
     The example cannula illumination implementations described herein generally relate to eye surgery. More particularly, the example implementations generally relate to illumination of a proximal end of a cannula. While the cannula illumination may be beneficial in a number of different applications, illumination of a proximal end of a cannula may be particularly beneficial in a darkened operating room during vitreoretinal surgery. In some implementations, a source of visible light may illuminate the proximal end of a cannula. The source of visible light may be the cannula, as the visible light may be emitted from the cannula itself. In other instances, the source of visible light may be external to the cannula, such as from a surgical instrument. In some implementations, the proximal end of the cannula may be considered illuminated as a result of visible light being emitted from the proximal end of the cannula as opposed to light being projected onto the proximal end. In some implementations, the proximal end may include a cannula hub that is operable to emit the visible light. For example, a tube portion may extend from the cannula hub toward a distal end of the cannula. A number of different techniques are described herein for illumination of the cannula hub. 
     The visible light emitted from the cannula permits a user, such as a surgeon, located in a darkened operating environment the ability to readily locate the cannula, such as when the user desires to insert a surgical instrument into the cannula. As a result, the illuminated cannulas described herein allows a surgeon to avoid disruptive activities that take the surgeon&#39;s attention away from the surgical procedure at hand, such as requiring the surgeon to zoom out a microscope being used by the surgeon to view a surgical site; switch on a microscope light in order to visualize the proximal end of the cannula and the instrument; or, once the instrument is introduced into the cannula, switching off the microscope lights before returning the surgeon&#39;s attention to the procedure at hand. The cannulas described herein also avoid the time associated with readjustment of the microscope delays the vitreoretinal surgery. 
       FIG. 1  illustrates an example of a surgical system  100  for illumination of a cannula  102 . As illustrated, the cannula  102  may include a proximal end  104  that emits visible light  106 , for example, providing visualization of the cannula  102  in an operating room environment  108  that may, for example, be darkened. Implementations of the surgical system  100  may further include a camera  110  that can collect information on an eye  112  and a microscope  114  that is operable to visually inspect the eye  112 . The surgical system  100  may also include a surgical console  116  that receives the information from the camera  110  and/or the microscope  114 . 
     The camera  110  may be any camera operable to collect information about the eye  112 . Example cameras  110 , include, but are not limited to, CMOS and CCD color cameras; monochromatic cameras with a broad wavelength in the visible range; cameras operable to detect near infrared or cameras operable to detect a specified wavelength in visible-near-infrared range. The camera  110  may be in signal communication with the surgical console  116  in any number of ways, such as, for example a wired or wireless connection. For example, the information collected by the camera  110  may be sent to the surgical console  116  for further processing. In some implementations, the information collected by the camera  110  may be sent to the surgical console  116  through a communication line  118  that communicatively couples the camera  110  to the surgical console  116 . As explained previously, the camera  110  may be in communication with the surgical console  116  in other ways. Thus, in other implementations, the camera  110  may be in wireless communication with the surgical console  116 . Consequently, the communication line  118  may be eliminated. In some implementations, the camera  110  may be optimized for use in low light levels, such as during vitreoretinal surgery where the operating room environment  108  may be dark. In some implementations, the eye  112  may be illuminated with light outside of the visible spectrum and still detectable by the camera  110  so as to avoid disturbing the surgeon. In some implementations, the camera  110  may be mounted on the microscope  114 , as shown. In other implementations, the camera  110  may be integrated into the microscope  114 . For example, the cameral  110  may be built into the optical path of the microscope  114 , such as, for example, with the use of a semi-transparent beam splitter. In some implementations, the camera  110  may receive information about the eye  112  and provide this information about the eye  112  to the surgical console  116 . 
     The microscope  114  may be any microscope operable to visually inspect the eye  112 , including, but not limited to, an ophthalmic surgical microscope or a stereo microscope, among others. A user, such as a surgeon or other medical professional, may operate the microscope  114  during surgery, for example, to visual the eye  112  (or specific portions thereof) in more detail. The microscope  114  may be in signal communication with the surgical console  116  via any number of connection methods, such as, for example, a wired or wireless connection. For example, the information collected by the microscope  114  may be sent to the surgical console  116  for further processing. In some implementations, the information collected by the microscope  114  may be sent to the surgical console  116  through the communication line  118  that communicatively couples the microscope  114  to the surgical console  116 . In other implementations, the microscope  114  may be wirelessly connected to the surgical console  116  such that information is communicated wirelessly therebetween. In such instances, the communication line  118  may be omitted. While not shown, the microscope  114  may include additional equipment, including, but not limited to, a light source. 
     With continued reference to  FIG. 1 , the surgical system  100  also includes a surgical instrument  120 . The surgical instrument  120  may include any instrument for use in the surgical procedure, including, but not limited to, an ophthalmic endoilluminator, a vitrectomy probe, forceps, scissors, a backflush, a soft tip cannula, a pic, and a scraper, among others. In some instances, the surgical instrument  120  couples to the surgical console  116  with a connection line  122 . In some instances, the connection line  122  may provide power to the surgical instrument  120 , data communication, or both. Power provided to the surgical instrument  120  may be in the form of electrical power, pneumatic power, hydraulic power, of in some other form. In other implementations (not shown), the surgical instrument  120  is not coupled to the surgical console  116 . Thus, in some instances, the connection line  122  may be omitted. 
     As illustrated in the example of  FIG. 1 , one or more cannulas  102  may be disposed in the eye  112 .  FIG. 1  shows two cannulas  102  disposed in the eye. However in other implementations, additional or fewer cannulas  102  may be disposed in the eye. 
     With the cannula  102  disposed in the eye  112 , the proximal end  104  of the cannula  102  extends from the eye  112 . The cannula  102  provides access into the interior of the eye  112 . For example, the cannula  102  includes a lumen through which an instrument, such as the surgical instrument  120  or a different instrument, may be inserted to access the interior of the eye  112 . The proximal end  104  of the cannula  102  may be operable to emit visible light  106 . As indicated above, while the present illustration shows two cannulas  102  disposed in the eye  112 , it should be understood that one, two, three, four, or more cannulas  102  may be used as desired by one of ordinary skill the art for a particular application. In some implementations, the cannula  102  may be a trocar cannula, an infusion cannula, or other desired cannula for use in the eye surgery. 
     In operation, the surgical instrument  120  may be inserted into the eye  112  through the cannula  102 . However, as previously described, the operating room environment  108  may be darkened, for example, so that ambient light in the operating room environment  108  does not interfere with visualization through the microscope  114 . Consequently, with the operating room environment  108  in a darkened condition, inserting the surgical instrument into cannula  102  may be challenging. In some implementations, the proximal end  104  of the cannula  102  may be operable to emit visible light  106 , thus allowing visualization (or improved visualization) of the proximal end  104 , even in the darkened condition of the operating room environment  108 , so that the surgical instrument  120  can be inserted into the cannula  102 . Thus, cannulas within the scope of the present disclosure are constructed and operable to emit visible light so that a user can more easily locate the cannula and a proximal end thereof in a darkened environment and insert an instrument into and through the cannula. 
       FIG. 2  is a schematic illustration of another example surgical system  200  used to explain an example technique for illumination of the proximal end  104  of the cannula  102 . In the examples described below, the proximal end  104  of the cannula  102  is described as having a luminescent material included therewith or applied thereto. However, the scope of the disclosure is not so limited. Rather, in other implementations, one or more luminescent materials may be added to other parts of the cannula  102  or to an entirety of the cannula  102 . Further, a luminescent material may be included with or applied to other types of medical instruments used in a surgical procedure to permit the instruments to be readily visible in a darkened surgical environment without disrupting a surgeon or other medical professional participating in the surgical procedure. 
     As illustrated in  FIG. 2 , the proximal end  104  of the cannula  102  may include or have applied thereto luminescent materials  202  as a source of visible light  106 . Example luminescent materials  202  include materials that exhibit luminescence, for example, by emitting light through fluorescence, phosphorescence, chemiluminescence, or radioluminescence. Examples of luminescent materials  200  within the scope of the present disclosure include, but are not limited to, fluorescent materials, phosphorescent materials, chemiluminescent materials, and radioluminescence materials. Some example fluorescent materials and phosphorescent materials within the scope of the present disclosure exhibit luminescent by emitting the visible light  106  after absorption of light. 
     In some implementations, the luminescent materials  202  may include fluorescent materials that emit the visible light  106  after absorption of light in the ultraviolet spectrum (e.g., UV light  204 ). By emission of the visible light  106  from the luminescent materials  202  that includes one or more fluorescent materials, the proximal end  104  of the cannula  102  may be visualized during the surgery. In some implementations, the luminescent materials  202  may include phosphorescent materials that emit the visible light  106  relatively slowly (as compared to fluorescent materials) after exposure to charging light  206 . One or more phosphorescent materials may be added or applied to the proximal end of the cannula  102  such that the proximal end  104  may be made visible during a surgical procedure. 
     Natural or artificial light, such as natural or artificial light present within the operating room environment  108 , may be used to charge luminescent materials (either fluorescent or phosphorescent) so as to cause the luminescent materials  202  to emit visible light. This natural or artificial light that may be used solely or in part to charge the luminescent materials  202  may be present in the operating room environment  108  prior to darkening of the operating room environment  108 . When the operating room environment  108  is in a darkened condition, the luminescent materials  202  emit the visible light  106  such that the proximal end  104  of the cannula  102  is visible during the surgery. 
     In some implementations, the luminescent materials  202  may include chemiluminescent materials that emit the visible light  106  as a result of a chemical reaction. The luminescent materials  202  in the form of one or more chemiluminescent materials may be applied to or included in the proximal end  104  of the cannula  102  and allowed to react such that the visible light  106  is emitted thereby. The visible light  106  emitted by the chemiluminescent material permits the proximal end  104  of the cannula  102  to be visible to a user in a darkened operating room environment  108  during a surgical procedure. 
     In some implementations, the luminescent materials  202  may include radioluminescent materials that emit the visible light  106  as a result of ionizing radiation, such as alpha particles, beta particles, or gamma rays. An example of a radioluminescent material within the scope of the disclosure includes tritium, which may be used in combination with a phosphor material. In some implementations, tritium may release electrons that interact with the phosphor material to generate fluorescent light. Similar to the other examples describe herein, the tritium in combination with a phosphor material may be applied to or included with the proximal end  104  of the cannula  102 . 
     The example surgical system  200  shown on  FIG. 2  may also include an ultraviolet light source  208 . The ultraviolet light source  208  may be a black light, a short-wave ultraviolet light, gas-discharge lamp, and ultraviolet light emitting diode, or another light source operable to emit ultraviolet radiation. The ultraviolet light source  208  may be used, for example, when the luminescent materials  202  include the fluorescent materials. The UV light  204  emitted by the ultraviolet light source  208  is absorbed by the luminescent materials  202 , causing the luminescent materials  200  to emit the visible light  106 . The ultraviolet light source  208  may be disposed at any position in the operating room environment  108  where the UV light  204  may impinge upon the proximal end  104  of the cannula  102 . In the illustrated example of  FIG. 2 , the ultraviolet light source  208  is attached to the microscope  114 . The ultraviolet light source  208  may be attached to the microscope  114  in any manner, including an adhesive, a fasteners, magnets, hook and loop fasteners, or any other manner operable to attach the ultraviolet light source to the microscope  114 . In other instances, the ultraviolet light source  208  may be integrated into the microscope  114 . In still other instances, the ultraviolet light source  208  may be disposed on or incorporated into another piece of equipment or provided as a separate piece of equipment within the operating room environment  108 . 
       FIG. 3  illustrates an example cannula  102  in which a trocar  306  is inserted within a lumen  124  defined by the cannula  102 . The proximal end  104  of the cannula  102  includes the luminescent material  204  as a source of the visible light  106 . As illustrated, the proximal end  104  of the cannula  102  includes a cannula hub  300  and a tube portion  302  extending from the cannula hub  300  towards a distal end  304  of the cannula  102 . As illustrated, the trocar  306  is extends through the lumen  124  of the cannula  102 . The trocar  306  includes a shaft portion  308  and a blade portion  310 . The blade portion  310  extends distally from the shaft portion  308 . With the cannula  102  and trocar  306  assembled as shown in  FIG. 3 , the blade portion  310  may be used to pierce an eye and the assembly advanced into the eye until, for example, the cannula hub  306  abuts the exterior surface of the eye. Thereafter, the trocar  306  may be removed from the cannula  102 , leaving the cannula  102  resident in the eye such that the lumen  124  provides a passage through which a surgical device may be inserted into and recovered from the eye. 
     The luminescent material  202  is included in the proximal end  104  of the cannula  102 . In the example shown on  FIG. 3 , a coating  312  of the luminescent material  202  may be applied onto an outer surface of the proximal end  104 . By way of example, the coating  312  may be disposed on the cannula hub  300 . Non-limiting examples of the coating  312  include, but are not limited to, a paint, a sleeve, or other covering that may be applied onto a surface of the cannula  102 . In other implementations, the luminescent material  202  in the form of a coating may be disposed on other portions of the cannula  102 , either alone or in combination with those disposed in the cannula hub  300 . 
       FIG. 4  illustrates another example of the cannula  102 . As shown, a trocar  306  extends through a lumen  124  defined by the cannula  102 . The proximal end  104  includes the luminescent material  202  as a source of the visible light  106 . The proximal end  104  of the cannula  102  includes a cannula hub  300  and a tube portion  302  that extends from the cannula hub  300  towards a distal end  304  of the cannula  102 . The trocar  306  includes a shaft portion  308  and a blade portion  310 . The assembly of the cannula  102  and the trocar  306  functions similarly to that described above in  FIG. 3  in that the cannula  102  and trocar  306  may be used together to pierce and provide a passage into an interior of an eye. 
     In the example shown in  FIG. 4 , the luminescent material  202  is included in the cannula hub  300  at the proximal end  104  of the cannula  102 . Particularly, the luminescent material is embedded in the cannula hub  300 . In some instance, the luminescent material  202  may be disposed entirely within (i.e., encased by) an interior portion  400  of the cannula hub  300 . That is, in some implementations, some or all of the luminescent material  202  may be encased within the interior portion  400 . 
     The luminescent material  202  may be in the form of nodules or spheres embedded within the cannula hub  300 . In other instances, the luminescent material  202  may be in the form of a continuous or discontinuous strip embedded within the proximal end  104 , such as the cannula hub  300 . In still other instance, the luminescent material  202  may have any desired shape, including, but not limited to, ovular, discus, platelet, toroidal, polygonal, and rod-like. The cannula hub  300  may be translucent or transparent to allow the visible light  106  from the luminescent material  202  to be emitted through the cannula hub  300  and released into the environment. In other implementations, the luminescent material  202  in the form of nodules, spheres, or strips, may be disposed in other portions of the cannula  102 , either alone or in combination with those disposed in the cannula hub  300 . 
       FIG. 5  illustrates another example of the cannula  102  in which the proximal end  104  includes containers  500  that contain the luminescent material  202  to provide visible light  106  in a darkened operating environment. The containers  500  may be disposed on or at least partially in the cannula hub  300 . For example, one or more of the containers  500  may be disposed on the exterior surface of the cannula hub  300 . In some instances, an exterior surface of the containers  500  may be flush with the exterior surface of the cannula hub  300  so that the exterior surface of the proximal end  104  is continuous. In other instances, one or more of the containers  500  may be raised relative to the exterior surface of the cannula hub  300 . In other implementations, the containers  500  may be provided in other portions of the cannula  102 , either alone or in combination with the cannula hub  300 . Otherwise, the cannula  102  may be similar to the cannulas described above in reference to  FIGS. 3 and 4 . Thus, the cannula  102  shown in  FIG. 5  may be used in combination with a trocar, which may be similar to trocar  306 , to pierce an eye and provide a passage between the interior of the eye and the exterior of the eye. 
     With continued reference to  FIG. 5 , because some or all of the containers  500  are either located on an exterior surface of the cannula  102  or extend through the exterior surface of the cannula  102 , the material forming the cannula  102  (or the portion of the cannula  102  that includes the containers  500 ) need not be transparent or translucent. However, the material forming the cannula  102  or a portion thereof may be transparent or translucent. 
     Non-limiting examples of the container  500  include vials, such as plastic or glass, that contain the luminescent material  202 . In some implementations, the luminescent material  202  may include one or more radioluminescent materials, such as tritium, and a fluorescent material, such as a phosphor material. As explained above, the tritium may release electrons that interact with the phosphor material to generate the visible light  106  emitted from the proximal end  104 . 
       FIG. 6  illustrates another example of the cannula  102  that may similar to the cannulas described above with respect to  FIGS. 3-5 . For example, the cannula  102  includes a proximal end  104 , a cannula hub  300 , a tube portion  302 , a distal end  304 , and a lumen  124  than extends along a longitudinal axis  602  of the cannula  102 . However, the cannula  102  shown in  FIG. 6  includes a luminescent material  202  is in the form of a chemiluminescent material. 
       FIG. 7  shows a luminescent container  700  that contains a chemiluminescent material. The example luminescent container  700  contains an arrangement of a first reactant  701  and a second reactant  702 . In the illustrated example, the first reactant  701  surround the second reactant  702 . However, the arrangement of the first and second reactants  701  and  702  shown in  FIG. 7  is merely one possible arrangement, and other arrangements of the first reactant  701  and second reactant  702  are within the scope of the present disclosure. When the first reactant  701  and second reactant  702  of the luminescent arrangement  700  mix, a chemiluminescence reaction occurs so as to emit visible light. 
     To separate the first reactant  701  and the second reactant  702 , the second reactant  702  may be disposed in an interior container  704 . In operation, the combination of the first reactant  701  and the second reactant  702  may be combined at any desired time so that the visible light is emitted for visualization of the cannula  102 . For example, the first reactant  701  and the second reactant  702  may be mixed just prior to placement of the cannula  102  during surgery or after placement of the cannula  102 , but prior to darkening of an operating room environment, such as the operating room environment  108  discussed above. The moment when the first reactant  701  and the second reactant  702  are combined may depend on, for example, the particular luminescent materials chosen, the duration of time the combined reactants  701 ,  702  will emit visible light, and the expected duration of the surgical procedure. The first reactant  701  and the second reactant  702  may be combined in any way operable to generate the visible light  106 . The interior container  704  may be made from a material that is more fragile than the luminescent container  700  so that when the luminescent container  700  undergoes a selected level of stress, the interior container  704  may break to release the second reactant  702  for contact with the first reactant  700  while leaving the luminescent container  700  unbroken. 
     In some instances, the luminescent container  700  may be made from any material operable to provide resistance to fracture under a defined stress level or loading. Example materials include, but are not limited to, glass, plastics (such as, for example, polyethylene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, polyamide, and poly(methyl acrylate)), or other materials that are solid at room temperatures, such as gelatins. The luminescent container  700  may be translucent or transparent, for example, to allow the visible light  106  from the chemiluminescence reaction to be emitted through the luminescent container  700 . The interior container  704  may also be made from, for example, glass, brittle plastics (such as polyethylene terephthalate, poly(methyl acrylate), and polystyrene), or other materials that are solid at room temperatures. However, in the case of the interior container  704 , the material forming the interior container  704 , the physical characteristics (e.g., shape, wall thickness, etc.) may be selected so as to fracture and release the contents thereof at the defined stress level or loading that would otherwise leave the luminescent container  700  unbroken. 
     The cannula hub  300  of the cannula  102  shown in  FIG. 6  may be translucent or transparent, for example, to allow the visible light  106  from the chemiluminescence reaction to be emitted through the cannula hub  300 . The cannula hub  300  includes cavities  604  in which a luminescent arrangement  700  may be disposed. Particularly, in some implementations, each of the cavities  604  may receive one of the luminescent arrangements  700 . Although two cavities  604  are shown, other implementations may include additional or fewer cavities  604 . The luminescent containers  700  are sources of visible light  106  for illumination of the cannula  102 . When the chemiluminescent material is activated (e.g., by fracturing of the interior container  704  so that the first reactant  701  and the second reactant  702  mix), visible light  106  is emitted from the luminescent arrangements  700  so as to illuminate the cannula  102 . 
       FIG. 8  illustrates a cross-sectional view of the cannula  102  of  FIG. 6  taken along line  8 - 8 .  FIG. 8  also shows a side view of an example trocar  306  insertable into the cannula  102 . As illustrated, the cannula  102  includes a proximal end  104  with a cannula hub  300  and a tube portion  302  that extends from the cannula hub  300  toward a distal end  304  of the cannula  102 . The cannula  102  also includes a lumen  124  that extends along longitudinal axis  602  of the cannula  102 . In the illustrated example, luminescent containers  700  are shown disposed in cavities  604  in the cannula hub  300 . Although  FIG. 8  shows two luminescent containers  700 , other implementations may include fewer or additional luminescent containers  700 . 
     As illustrated, the luminescent containers  700  disposed in the cavities  604  in the cannula hub  300  protrude into the lumen  124 . As previously described the luminescent containers  700  each hold a first reactant  701  and a second reactant  702 . As also described above, the second reactant  702  may be disposed in an interior container  704 , the interior container  704  disposed within the luminescent container  700 . The interior container  704  forms a barrier between the first reactant  701  and the second reactant  702  and prevents premature mixing of the first reactant  701  and the second reactant  702 . 
     The trocar  306  is insertable into the lumen  124  defined by the cannula  102 . As shown, the example trocar  306  includes a trocar hub  800 , shaft portion  308 , and a blade portion  310 . The shaft portion  308  extends between the trocar hub  800  and the blade portion  310 . As illustrated, the shaft portion  308  includes an enlarged portion in the form of shoulder portion  802 . The shoulder portion  802  is configured to abut corresponding seat portion  804  in cannula hub  300 . The shoulder portion  802  and seat portion  804  cooperate to limit an amount by which the trocar  306  is permitted to be inserted into the lumen  124  of the cannula  102  when the trocar  306  is disposed in the cannula  102 . 
     In some implementations, movement of the trocar  306 , while disposed in the lumen  124 , relative to the cannula  102  (e.g., insertion of the trocar  306  into or removal of the trocar  306  from the cannula  102 ) may cause the trocar  306  to engage the luminescent containers  700 . This engagement of the trocar  306  with the luminescent containers  700  may cause the first reactant  701  and the second reactant  702  to combine or mix (such as by fracture of the interior container  704  that contains the second reactant  702 ). For example, with the trocar  306  disposed in the lumen  124  of the cannula  102 , removal of the trocar  306  from the cannula  102  the trocar  306  may interact with or otherwise disrupt the luminescent containers  700  to cause the first reactant  700  and the second reactant  702  to combine and generate light. In some instances, this interaction or disruption may case the interior container  704  to fracture or bust, releasing the second reactant  702  so as to combine with the first reactant  701 . 
     For example, withdrawal of the trocar  306  from the cannula  102  may cause the shoulder portion  802  of the trocar  306  to engage the luminescent containers  700 . In some implementations, this engagement may cause breakage of the interior containers  704 , as the interior containers  704  may be more fragile than the luminescent containers  700 , such that the first reactant  700  contacts and mixes with the second reactant  702  to generate light. It should be understood that  FIGS. 6-8  illustrate one technique for illuminating the proximal end  104  of the cannula  102  using a chemiluminescence reaction and that other configurations of the cannula  102  and trocar  306  may be used to achieve the desired chemiluminescence reaction. 
       FIG. 9  illustrates another example configuration of the trocar  306  that may be used with the luminescent containers  700  to produce a chemiluminescent reaction in response to movement of a trocar relative to a cannula. For the sake of clarity, the cannula  102  is not shown on  FIG. 9  and a single luminescent container  700  is shown. As illustrated, the trocar  306  includes a shaft portion  308  and a blade portion  310  that extends distally from the shaft portion  308 . In the illustrated example, the shaft portion  308  includes a cutout or notch  900  that forms a ledge  902 . In operation, movement of the trocar  306  relative to the cannula and, more particularly, to the luminescent container  700  (e.g., by removal of the trocar  306  from the cannula or insertion of the trocar  306  into the cannula) activates the chemiluminescence reaction in the luminescent container  700  such as by fracturing an interior container  704  within the luminescent container  700  to cause a first reactant to mix with a second reactant and produce light. 
       FIG. 10  is an example that illustrates the trocar  306  of  FIG. 9  disposed in a cannula  102 . As illustrated, the cannula  102  includes a proximal end  104  with a cannula hub  300  and a tube portion  302  that extends from the cannula hub  300  toward a distal end  304  of the cannula  102 . The cannula  102  also includes a lumen  124  that extends along longitudinal axis  602  of the cannula  102 . In the illustrated example, luminescent containers  700  (two in this example, although additional or fewer luminescent containers  700  are within the scope of the disclosure) are shown disposed in cavities  604  in the cannula hub  300 . As illustrated, the luminescent containers  700  protrude, at least partially, into the lumen  124 . 
     The trocar  306  is illustrated as residing within the lumen  124  of the cannula  102 . In this example also, a shaft portion  308  of the trocar  306  includes notches  900  that define ledges  902 . However, in the example shown in  FIG. 10 , the notches  900  have a smoother contour than those shown in  FIG. 9 . The ledges  902  are configured to interact with the adjacent luminescent containers  700 . As previously described the luminescent containers  700  each hold a first reactant  701  and a second reactant  702 . The second reactant  702  may be disposed in an interior container, such as interior container  704  described above. The interior container  704  is disposed in the luminescent container  700  to prevent premature mixing of the first reactant  701  and the second reactant  702 . 
     With continued reference to  FIG. 10 , movement of the trocar  306  may cause the trocar to engage the luminescent containers  700  such that combination of the first reactant  701  and the second reactant  702  occurs. For example, the cannula  102  may be provided with the trocar  306  received within the lumen  124  of the cannula  102 . When the trocar  306  is removed from the cannula  102 , the trocar  306  interacts with the luminescent containers  700  to cause the first reactant  701  and the second reactant  702  to combine. For example, the withdrawal of the trocar  306  may cause the ledge  902  formed by the notch  900  to engage the luminescent containers  700 . In some implementations, this engagement may cause breakage of the interior containers  704 , as the interior containers  704  may be more fragile than the luminescent containers  700 , resulting in a chemiluminescent reaction and production of visible light. 
     Assembly of a trocar (which may be similar to one or more of the trocars  306  described herein), a cannula (which may be similar to one or more of the cannulas  102  described herein), and a luminescent container (which may be similar to one or more of the luminescent containers  700  described herein) may be performed such that insertion of the trocar into the cannula prevents activation of the luminescent container (e.g., by the fracture of an interior container to cause a first reactant and a second reactant to mix to generate light). For example, in some implementations, one or more luminescent containers may be inserted or otherwise coupled to the cannula after insertion of the trocar thereinto. As a consequence, the trocar engages the one or more luminescent containers only when the trocar is withdrawn from the cannula, thereby causing activation of the one or more luminescent containers to produce light. 
     In other implementations, one or more luminescent containers may be installed in the cannula before the trocar is inserted thereinto without activating the one or more luminescent containers. For example, the trocar may be formed such that the trocar is able to pass by the luminescent container while being inserted into the cannula without activating the luminescent container. However, withdrawal of the trocar from the cannula disrupts the luminescent container such that the luminescent container activates and produces light. For example, the trocar may include a feature having a contour that gradually engages the luminescent container when the trocar is inserted into the cannula but otherwise prevents activation of the luminescent container. However, the features of the trocar may abruptly engage the luminescent container when the trocar is removed from the cannula, causing the luminescent container to activate (e.g., by fracturing an interior container to cause a first reactant and a second reactant to mix and produce light). 
       FIG. 11  shows a proximal end  104  of another example of the cannula  102 . In this illustrated example, the proximal end  104  emits visible light  106  that is transmitted to the proximal end  104  via an optical fiber  1100 . The optical fiber  1100  is coupled to the proximal end  104  of the cannula  102 . With reference to  FIG. 12 , the optical fiber  1100  is coupled to a light source  1200  that is remote from the cannula  102 . The optical fiber  1100  optically couples the light source  1200  to the cannula  102 . As illustrated, the optical fiber  1100  extends from the light source  1200  and connects to the cannula hub  300 . 
     The visible light  106  travels from the light source  1200 , through the optical fiber  1100 , to the cannula  102 , and is emitted from the proximal end  104 . As described above, the emitted visual light  106  permits the cannula  102  to be visible to a user in in an environment with low ambient light levels, such as a darkened operating room environment during a surgical procedure. 
     In some implementations, the visible light  106  may be emitted from the cannula hub  300 . In some implementations, the cannula hub  300 may be translucent or transparent, to allow the visible light  106  transmitted by the optical fiber  1100  to be emitted through the cannula hub  300 . In some implementations, the cannula hub  300  may be made from a semi-transparent material with or without one or more diffusing additives. The diffusing additives may be distributed within the cannula hub  300  to provide uniform illumination of the entire cannula hub  300 . 
     The light source  1200  may be any light source including, but not limited to, a light-emitting diode (LED) light source, a phosphor light source, laser light source, halogen light source, xenon light source, or Mercury Vapor light source. Non-limiting examples of laser light sources include monochromatic (e.g., infrared, visible), multi-spectral, or supercontinuum white lasers. The optical fiber  1100  carries the visible light  106  from the light source  1200  to the cannula  102 . The optical fiber  1100  may be any optical fiber operable to transmit light, including, but not limited to, optical fibers made from glass or plastic. 
       FIGS. 13A and 13B  illustrate another example in which optical fiber  1100  transmits visible light to the cannula  102  so that the cannula  102  becomes illuminated and visible in a darkened environment.  FIG. 13A  is a top view of the cannula  102 , and  FIG. 13B  is a side view of the cannula  102 . As illustrated, the cannula  102  includes a cannula hub  300  at proximal end  104  thereof and a tube portion  302  that extends from the cannula hub  300  towards a distal end  304  of the cannula  102 . 
     As illustrated, an optical fiber  1100  is coupled to a lights source  1200  at a first end and is coupled to the cannula hub  300  at a second end. The optical fiber  1100  transmits light (in the form of visible light  106 ) from the light source  1200  to the cannula  102 . The visible light  106  is emitted from the hub  300  so that the cannula  102  may be visible in a darkened or low ambient light level environment, such as, for example, an operating room environment. In some implementations, the cannula hub  300  may be translucent or transparent, for example, to permit passage of the visible light  106  from the optical fiber  1100  out of the cannula hub  300 . In some implementations, the cannula hub  300  may be made from a semi-transparent material with or without one or more diffusing additives. The diffusing additives may be distributed within the cannula hub  300  to provide uniform illumination of the entire cannula hub  300 . 
     An additional optical fiber  1300  extends from the light source  1200  to the cannula  102 . The optical fiber  1300  is coupled to the light source  1200  as a first end. The light fiber extends along an exterior surface of a tube portion  302  of the cannula  102 . A distal end  1304  of the optical fiber  1300  is be disposed adjacent to the distal end  304  of the cannula  102 , as shown in  FIG. 13B . In some instances, the distal end  1304  of the optical fiber  1100  may be aligned with the distal end  304  such that the optical fiber  1100  does not extend distally beyond the distal end  304  of the cannula  102 . 
     Visible light provided by light source  1200  is transmitted through the optical fiber  1300  and emitted from the distal end  1304  in the form of visible light  1302 . The visible light  1302  provides illumination to an interior of an eye when the cannula  102  is disposed in the eye. Although not shown on  FIGS. 13A and 13B , in some instances, the optical fiber  1100  and the optical fiber  1300  may be bundled together. Further, in some implementations, the bundled optical fibers  1100  and  1300  may include a beam splitter. The beam splitter is operable to guide a portion of the visible light  106  generated by the light source  1200  into the optical fiber  1100  and also guide a portion of the visible light  106  generated by the light source  1200  into the optical fiber  1300 . The portion of the visible light  106  transmitted through the optical fiber  1100  is conveyed to the cannula hub  300 , while the portion of the visible light  106  transmitted through the optical fiber  1300  is conducted to the distal end  1304  and emitted therefrom. While only a single light source  1200  is shown on  FIGS. 13A and 13B , it is within the scope of the disclosure that multiple lights sources may be used. For example, in some instances, a first light source may be used to generate light for transmission through the optical fiber  1100 , and a second light source may be used to generate light for transmission through the optical fiber  1300 . 
       FIG. 14  illustrates another example cannula  102  in which a single optical fiber  1100  is used to provide illumination to both a cannula and to an interior of an eye. In the illustrated example, visible light generated by light source  1200  is introduced into and transmitted along optical fiber  1100 . The optical fiber  1100  is coupled to the hub  300  and releases a portion of the visible light into the hub  300 . This portion of the visible light, i.e., visible light  106 , is emitted from the hub  300  so that the cannula  102  is visible, such as in an environment having low ambient light (e.g., a darkened operating environment). A portion of the visible light passing through the optical fiber  1100  continues therealong until being released from the distal end  1400  of the optical fiber  1100 . This portion of the visible light, i.e., visible light  1302 , provides illumination, such as to an interior of an eye when the cannula  102  is inserted into the eye. As shown, the distal end  1400  of the optical fiber  1100  may be adjacent to the distal  304  of the cannula. In some instances, the distal end  1400  of the optical fiber  1100  may be aligned with the distal end  304  such that the optical fiber  1100  does not extend distally beyond the distal end  304  of the cannula  102 . 
       FIG. 15  is a detail view of an interface between the optical fiber  1100  and the hub  300  of the cannula shown on  FIG. 14  taken along circle  15 . As illustrated, light  1500  traveling along the optical fiber  1100  is transmitted into the hub  300  via a plurality of defects or modifications  1504  formed or introduced into the optical fiber  1100 . For example, the modifications  1504  may be formed or introduced into a cladding of the optical fiber  1100  and operate to permit some of the light traveling through the optical fiber  1100  to escape at the modifications  1504 . This portion of the light  1500  that is transmitted into the hub  300  is emitted from the hub  300  as visible light  106 . The remainder of the light  1500  is transmitted along the remainder of the optical fiber  1100  where the light  1500  is emitted from the distal end  1400 , as shown in  FIG. 14 . 
     The optical fiber  1100  includes a cladding  1502 . A portion of the light  1500  traveling along the optical fiber  1100  may be emitted as visible light  106  through the cladding  1502 . In some instances, the cladding  1502  may be modified, such as during production of the optical fiber  1100  or some time thereafter, to include the plurality of modifications  1504 . Numerous techniques may be used to modify the cladding  1502 , including, but not limited to, inclusion of modifications  1504  in the cladding  1502  through which the visible light  106  may be emitted. Introduction of the modifications  1504  decreases the amount of light available for emission of visible light  1302  at the distal end  1400  (e.g., shown at  FIG. 14 ), but allows the visible light  106  to illuminate the cannula hub (e.g., shown on  FIG. 14 ). 
       FIG. 16  illustrates another example of a cannula that uses an optical fiber for illumination thereof. In the illustrated example, an optical fiber  1100  is coupled to a light source  1200  at a first end and to a cannula  102  at a second end. In the illustrated example, the optical fiber  1100  is coupled to a hub  300 , formed at a proximal end  104  of the cannula  102 . The optical fiber  1100  transmits visible light  106  generated by the light source  1200  to the cannula  102 . The visible light  106  travels from the light source  1200 , through the optical fiber  1100 , and to the cannula  102 . The visible light  106  is conducted to the hub  300  of the cannula  102  and is emitted therefrom. The emitted visible light  106  may be used to visualize the cannula  102  in a darkened environment, such as an operating room during a surgical procedure. 
     An illumination probe  1600  is disposed in the cannula  102 , and a tip  1602  of the probe  1600  extends from a distal end  304  of the cannula  102 . Light is provided to the illumination probe  1600  via an optical fiber  1300 . In the example illustrated, the optical fiber  1300  is optically coupled to the light source  1200  such that the light source  1200  provides light to the illumination probe  1600 . However, in other implementations, a light source separate from light source  1200  may be used to provide light to the illumination probe  1600 . In still other instances, the illumination probe  1600  may generate light internally. As illustrated, visible light  1302  provided by the light source  1200  and transmitted along the optical fiber  1300  is emitted from the tip  1602 . 
       FIG. 17  illustrates another example for illumination of a cannula  102 . As shown, a surgical instrument  120  shown inserted into the cannula  102  includes a light source  1700 . The light source  1700  emits visible light  106  for illumination of the proximal end  104  of the cannula  102 . The visible light  106  allows visualization of the cannula hub  300 , formed at the proximal end  104 , such as in a darkened environment, such as operating room environment  108 . The light source  1700  may be any light source, including, but not limited to, an incandescence lamp, a light-emitting diode, or a laser. The light source  1700  may be attached to the surgical instrument  120  in any number of ways, including, but not limited to, mechanical fasteners, adhesives, magnets, an interlocking feature, a threaded connection, etc. In the illustrated example, a clamp  1702  secures the light source  1700  to a portion of the surgical instrument  120 . As particularly shown, the clamp  1702  secures the light source  1700  to a handle  1704  of the surgical instrument  120 . While not shown, the light source  1700  may alternatively be integrated into the surgical instrument  120 . The surgical instrument  120  may be any instrument for use in a surgical procedure, including, but not limited to, an ophthalmic endoilluminator, a vitrectomy probe, forceps, scissors, backflush, soft tip cannula, pic, an irrigation handpiece, an aspiration handpiece, an integrated irrigation and aspiration handpiece, and scraper, among others. 
       FIG. 18  illustrates another example for illumination of a cannula  102 . In the illustrated example, an illumination probe  1600 , such as an endoilluminator, emits visible light  106 , a portion of which is used to illuminate the proximal end  104  of the cannula  102 . The illumination probe  1600  includes a handle  1800  and a sleeve  1802 . The sleeve  1802  extends from a distal end  1804  of the handle  1800  to a distal end  1806  of the sleeve  1802 . The visible light  106  is emitted from distal end  1806  of the sleeve  1802 . The visible light  106  is also emitted from distal end  1804  of the handle  1800  and received by the hub  300  of the cannula  102 . With the illumination probe  1600  fully inserted into the cannula  102  such that the distal end  1804  of the handle  1800  abuts the hub  300  of the cannula, the visible light  106  emitted from the distal end  1804  of the handle  1800  is received by the hub  300  and emitted therefrom. 
     A light source  1200  produces the visible light  106  that is emitted by the illumination probe  1600 . In the illustrated example, a first optical fiber  1808  is optically coupled the light source  1200  at a first end of the first optical fiber  1808  and to the illumination probe  1600  at a second end of the first optical fiber  1808 . Light transmitted to the illumination probe  1600  via the first optical fiber  1808  provides light that is ultimately emitted from the distal end  1806  of the sleeve  1802 . A second optical fiber  1810  is optically coupled to the light source  1200  at a first end of the optical fiber  1810  and optically coupled to the illumination  1600  at a second end of the second optical fiber  1810 . The second optical fiber  1810  transmits light produced by light source  1200  that is ultimately emitted from the distal end  1804  of the handle  1800 . Although  FIG. 18  shows a single light source  1200  that provides light to both the first optical fiber  1808  and the second optical fiber  1810 , other implementations may include separate light sources, one of the separate light sources to provide light to the first optical fiber  1808  and a second light source to provide light to the second optical fiber  1810 . 
       FIG. 19  is an example method  1900  for providing a cannula for use in a surgical procedure that is operable to emit visible light. The method  1900  includes inserting a cannula into an eye at  1902 . The cannula may be of a type as described herein, such as, for example, any of the cannulas  102  described herein. At  1904 , the cannula emits visible light from at least a portion of the cannula. The visible light may be produced by a luminescent material that is disposed in, disposed on, or otherwise contained within a portion of the cannula, such as, for example, a luminescent material of a type described herein or otherwise operable to emit visible light. In other instance, the visible light may be produced remotely from the cannula but transported to a portion of the cannula where the visible light is emitted from at least a portion of the cannula. At  1906 , the method  1900  also includes disposing a surgical instrument through the cannula. 
     The method  1900  may include additional or different steps than those described. For example, the method  1900  may include a step of visually identifying the cannula with the aid of the emitted visible light. A step may also include reducing an ambient light level within an operating environment in which the cannula is located, e.g., a surgical environment. Another step may include utilizing the surgical instrument disposed within the cannula to perform a surgical procedure or portion thereof. 
     It is believed that the operation and construction of the present disclosure will be apparent from the foregoing description. While the present disclosure presents apparatus and methods shown and described herein, various changes and modifications may be made therein without departing from the spirit and scope of the disclosure.