Abstract:
A multi-piece punctal plug has one a superficial plug removably connected to an anchor plug deeper in the naso-lacrimal canaliculus. The anchor is fixed to the wall of the lacrimal duct while the superficial plug is axially and detachably secured to the anchor plug so that the multi-plug complex may be inserted or removed together as one, or the superficial plug may be detached separately and replaced securely without disturbing the anchor. Removal and insertion is accomplished by a specific tool having an end for reversibly engaging the plugs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. patent application Ser. No. 12/326,622 filed Dec. 2, 2008, which application is incorporated herein by reference and is now U.S. Pat. No. 8,______ issued ______. 
     
    
     FIELD AND BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to the field of ophthalmology, and in particular to a new and useful punctal plug that is made up of multiple parts to enhance its effectiveness. 
         [0003]    US Patent Application 2005/0232972 to the same inventor as the present application, is incorporated here by reference, and discloses a method and an apparatus for administering an active agent to a subject by applying the active agent to at least one surface of an ocular implant such as a punctal plug, and installing the implant, e.g. inserting the punctal plug into a punctal aperture of the subject. 
         [0004]    Although the use of punctal plugs to deliver a drug to the eye, or to the body, or for other purposes, is known, retention of the plugs over time continues to be problematic since the plugs tend to fall out prematurely. 
       SUMMARY OF THE INVENTION 
       [0005]    It is accordingly an object of the present invention to overcome the retention problem of current punctal plug delivery designs by providing a multi-piece punctal plug for any appropriate function, that has an anchoring component which is designed to be securely anchored in the lacrimal duct near the punctum, to receive a superficial plug component that, in turn, can be attached securely and detached at the practitioner&#39;s discretion, in a controlled fashion. 
         [0006]    This may be accomplished, according to the invention, and for example, by threading the superficial plug component to the anchoring component for a “screw in” and “unscrew” technique, or a mechanical spring loaded latching structure and process may be used, or a bayonet connection, or other reversible and controllable attachment mechanism and method that is currently known or that is here after discovered, may be used. 
         [0007]    The invention is directed to the punctal plug in general and may be embodied, for example as follows. 
         [0008]    1. A punctal plug of multi-piece design, specifically with an anchoring piece which sits deep within the canaliculus and is firmly attached to the walls using any method, e.g. a mechanical method with an expansile element to wedge the anchoring plug permanently in position, spring loaded prongs which emerge from the anchoring plug and fix it in position reversibly, or a chemical method which bonds it in place. 
         [0009]    2. A punctal plug of multi-piece design with a superficial part which is designed to attach, reversibly, to the deeper anchoring plug. Two possible but not limiting embodiments are using a screw-in method or a spring-loaded latching method as noted above, both enabling the removal of the superficial plug at the practitioner&#39;s discretion, while leaving the anchoring plug in place deeper in the canal. 
         [0010]    3. A punctal plug of multi-piece design in which the anchoring plug is designed to receive the superficial plug or plugs. This might include a screw in opening or a shape to receive a spring-loaded latch. 
         [0011]    4. A punctal plug of multi-piece design wherein either or all parts are imparted with medicine to deliver to the eye or the systemic circulation. 
         [0012]    5. A punctal plug of multi-piece design in which all pieces are possessed of a radio-opaque element which allows for identification on X-ray/imaging procedures. 
         [0013]    The invention includes the method for unscrewing or other wise disconnecting the superficial plug component from the anchoring plug or anchor component, as this has not been described previously. 
         [0014]    Accordingly, a further object of the invention is to provide a punctal plug that comprises an anchor for being received in a lacrimal duct and a plug for extending into the anchor, the anchor being fixed to the wall of the lacrimal duct and the plug being axially and detachably secured to the anchor so that with the plug connected to the anchor, the plug and anchor can be inserted into, and removed from the lacrimal duct using a tool having an end for engaging the plug. 
         [0015]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    In the drawings: 
           [0017]      FIG. 1  is a partial and schematic view of the eye and nose area of a patient who would benefit from the punctal plug arrangement of the present invention; 
           [0018]      FIG. 2  is an enlarged exploded view that is partly in section, of an embodiment of the invention; 
           [0019]      FIG. 3  is a view of the embodiment of  FIG. 2  in the lacrimal duct of a patient; 
           [0020]      FIG. 4  is a view similar to  FIG. 2  but of a further embodiment of the invention; and 
           [0021]      FIG. 5  is a view similar to  FIG. 2  but of a still further embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Referring now to the drawings, in which like reference numerals are used to refer to the same or similar elements,  FIG. 1  shows the eye and nose area of a patient who would benefit from the punctal plug arrangement of the present invention. To better understand the environment in which the invention will operate, the patient is shown to have an eye  10  above which are located lacrimal glands  12  for producing tears. The tears will wet and coat the eye and will eventually move to the upper and lower lid margins  14  and then be channeled to the upper and lower punctum  16 . The tears will then travel along the upper and lower canaliculus  18  and lacrimal ducts  20  (collectively referred to here simply as the lacrimal ducts), into the nasolacrimal duct  22  and then to the nasal cavity  24 . 
         [0023]    Referring now to  FIGS. 2 and 3 , a punctal plug arrangement  30  of the present invention is received in one of the lacrimal ducts  18 ,  20 , at or near the corresponding lacrimal punctum  16  of a patient. Since the patient has four such lacrimal ducts, up to four punctal plugs of the present invention can be used, each for a known mechanical purpose such as blocking the passage of tears or, with a passage through the plug, enhancing the passage of tears, or for a known medicating purpose such as supplying a medicament that is incorporated in the plug to the patient. According to the present invention, since each plug actually has two, or even more parts in some embodiments, and each can be loaded, using known technology, with a different medication, many more than four different medicaments can be supplied to one patient at the same time. 
         [0024]    Each punctal plug arrangement  30  of the invention includes at least one anchor  32 , and one plug  34 . The anchor  32  and plug  34  are each advantageously made of any bio-compatible material such as plastic, like silicone, or metal, like titanium, or metal impregnated plastic. It is also advantageous for either the anchor or the plug or both to be made of radio-opaque material or to be coated to be radio-opaque, so that the anchor and/or the plug are visible in an X-ray image. 
         [0025]    Referring now to  FIG. 2  in particular, the punctal plug arrangement  30  for placement in a lacrimal duct  20  of a patient, comprises the anchor  32  having an inner plug engaging recess  36  and an outer surface for engaging a wall of a lacrimal duct  20  for receiving the anchor. The plug  34  has a stem  38  for extending into the plug engaging recess  36  of the anchor  32 . The plug  34  also has a head  40  connected to the stem  38 , the head having a larger diameter then the stem for engaging around the lacrimal punctum  16  at an end of a lacrimal duct  18 ,  20 , in which the anchor is received. The head  40  includes a tool engaging recess  42  for receiving the end  52  of a tool  50  for placing and for removing the plug and anchor, to be described later in this disclosure. 
         [0026]    The anchor may have a radial skirt  44  to increase its fixation to the duct  20 , and, according to the invention, anchor fixing means  46  at the outer surface of the anchor  32 , such as a plurality of fixed or movable projections, provided for further fixing the anchor  32  to the wall of a lacrimal duct. The arrangement also includes plug fixing means such as a male thread on the stem  38  for treading into a female thread in the plug engaging recess  36 , for detachable and axially securely connecting the plug  34  to the anchor  32 , so that with the plug connected to the anchor, the plug and anchor can be inserted as a unit into, and removed as a unit from the lacrimal duct  20 . 
         [0027]    The arrangement of the invention includes the tool  50  having the end  52  for engaging the tool engaging recess  42  of the plug  34 , the end of the tool and the tool engaging recess being shaped for axial securement of the tool to the plug so that the tool can be used to positively hold the plug, to facilitate insertion and removal of the plug and connected anchor into and out from the lacrimal duct. 
         [0028]    In the embodiment of  FIG. 2 , this axial securement is achieved by making the tool engaging recess  42  of plug  34  larger at its base than at its entry end, and the end  52  of the tool to be radially expandable. Thus, with the tool end  52  in the tool engaging recess  42 , end  52  is expanded in the larger base of the tool engaging recess  42  so that the tool is axially fixed to the plug. With the plug  34  also axially fixed to the anchor  32 , e.g. by the threads, the plug plus the anchor, as a unit, can be securely held by the practitioner and inserted into the lacrimal duct through to punctum  16 . 
         [0029]    The radial expansion of tool end  52  can be provided by cutting a plurality of slots in the tool end  52  to form a plurality of prongs at the tool end, and by providing a central axial bore through the length of the tool  50 . The bore has a constant diameter at the top of the tool, and becomes slightly smaller or tapers inwardly at  58 , in the area of the tool end  52  and its slots and prongs. A cylindrical plunger  54  is slidably mounted into this cylindrical bore and has a top button end  56  that can be pressed by the practitioner. The lower end  60  of the plunger  54  stops just above the taper  58  in an initial condition of the tool  50 , so that the prongs defined by the slots at the tool end  52 , lay in the same plane as the six faces of the hexagonal tool body of tool  50 . In this initial condition the tool end  52  can be inserted into the tool engaging recess  42  which is also hexagonal so that rotation of the tool  50  can be used to screw the plug stem into the anchor. 
         [0030]    To axially secure the tool  50  to the plug  34 , button  56  is pressed downwardly with respect to the tool body so that the plunger end  60  will slide along the inside tapered surfaces  58 , and thereby cause the prongs to move radially outwardly into the enlarged base of tool receiving recess  42 . In this engaged condition the plug plus anchor unit can be securely held and manipulated by the practitioner using the tool. The prongs are maintained in the expanded state due to friction between the plunger end  60  and the surfaces  58 . Once the multi-part punctal plug  30  of the invention is in place, the practitioner will manually pull the plunger partly back out of the tool body to allow the prongs to spring back to their initial condition so that the tool end  52  can be released from the recess  42  and the plug  34 . 
         [0031]    The same procedure can be used to engage and extract the plug arrangement of the invention from the lacrimal duct. 
         [0032]    Referring now to  FIG. 4 , the multi-part punctal plug arrangement of the invention comprises an anchor  32 , plug  34  and tool  50 , but has plug fixing means for connecting the plug to the anchor that comprises at least one, but preferably two, three or four radially movable latches  66  on the plug stem  38 , and a latch seat  68  in the plug engaging recess  36  of the anchor, for detachably and axially securing the plug to the anchor. 
         [0033]    The tool  50  includes latch retracting means for retracting the latch  66 , radially inwardly to disengage the latch  66  from the latch seat  68  and disconnect the plug from the anchor. The anchor fixing means comprises a plurality of movable projections  47  on the outer surface of the anchor for engaging the wall of a lacrimal duct, the projections being radially movable and the tool including means for radially retracting the projections for facilitating removal of the anchor from the lacrimal duct. 
         [0034]    The latch retracting means for retracting the latch  66 , comprises an inner plunger  55  mounted for axial movement inside plunger  54  and having a lower end that engages the top of a pusher or push pin  70  mounted for axial movement inside plug  34 , when the tool is engaged to the plug head  40 . By pushing down on a second button  57  connected to the inner plunger  55 , push pin  70  will push down on a spring  72  connected on the inner side of each latch  66 , to pull the latch  66  radially inwardly, so it will clear latch seat  68  and allow the plug to be disconnected form the anchor. Since no rotational motion of the plug is needed, the body  51  of the tool  50  may be cylindrical rather than hexagonal and the tool engaging recess  43  is conical. Otherwise the tool end is expandable radially outwardly to engage the enlarged base of the tool engaging recess  43  by pushing down on button  56 , as in the embodiment of  FIG. 2 . 
         [0035]    The lower end of the push pin  70  will also transmit axial movement to a second spring  74 , e.g. a V-shaped spring connecting the projections  47  in anchor  32 , to pull the projections radially inwardly to disengage them from the walls of the lacrimal duct to allow the anchor to be pulled from the duct using the tool when the punctal plug arrangement is to be removed from the patient. 
         [0036]    Medicament sacks  80  and  82  are also schematically shown  FIG. 4 , as examples of where and how medicaments can be charged into the punctal plug of the invention. The material of the anchor can be semipermeable to allow the medicine to be dosed to the patient, or one or more small channels can be provided in the anchor for this purpose, or another known manner of dosing the patient can be used. 
         [0037]    As shown in  FIG. 5 , the multi-part punctal plug arrangement can build on the basic premise of the invention to provide more than two parts that can each be used for a different medicament in a single lacrimal duct. To this end the arrangement includes the anchor  32 , the plug  34  and at least one, but two, three or even more, intermediate punctal sections  90 , having an inner plug engaging recess  92  for receiving the stem  38  of plug  34 , and an outer surface for engaging a wall of a lacrimal duct, the intermediate section  90  also having a stem  94  for extending into the plug engaging recess  36  of the anchor  32  so that the intermediate punctal section can be detachably and axially secured between the plug  34  and the anchor  32 . 
         [0038]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.