Abstract:
A fixture and method is provided for in vitro storage of a cornea. The fixture includes a platform having a corneal-sceral rim receiving surface, a clamp having a mating surface for the cornel-scleral rim and handles. A locking mechanism is provided to secure a donor cornea between the clamp and platform. The combination cornea, platform and clamp are placed in a storage unit having a fluid preservation media. In one embodiment, the storage unit includes a vial having an optically clear closed end and an opened end. A lid is secured to the open end of the vial and engages the handles in order to stabilize the clamped cornea within the vial.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/622,234, filed Oct. 26, 2004. 
     
    
     FIELD OF INVENTION  
       [0002]     This invention relates to an apparatus and a method for the use and transplantation of human and animal corneas. In particular, it relates to the in vitro storage, securing, testing, preservation, and transportation of the corneas for use in medical and scientific procedures and research.  
       BACKGROUND  
       [0003]     Typical organ transplantation and storage usually requires cumbersome and somewhat inefficient apparatus. Often the individuals transporting human or animal organs employ large containers, packing materials and other items useful for storage of the organ. For example, such containers include: moisture resistant containers, plastic liners and/or Styrofoam crates. While these devices often provide stability and support for the organ, the bulkiness and lack of mobility, limit the functionality of the storage devices. Moreover, in cases where the organs are particularly smaller, such as corneas, these bigger storage units often fail to provide sufficient support to the organ, which increases the risk of damage to the organ during transport and also at the time of retrieval for a contemplated surgical procedure.  
         [0004]     Prior art attempted to address the issues associated with smaller organs by using smaller size containers to insert the organs. The smaller containers provided easier and more efficient transportation, but did not provide any easier access and still failed to provide complete support for the organ. These smaller containers often made retrieval of these donor corneas more difficult at the time of the surgical procedure.  
       SUMMARY OF THE INVENTION  
       [0005]     This invention offers an alternative to the more traditional approaches to organ transportation and storage. In particular, the invention relates to the transportation and storage of an animal or human cornea.  
         [0006]     In one embodiment of the invention, a ring or platform has a receiving surface upon which the donor cornea rests. The platform is stabilized by legs connected to the bottom side of the platform. The platform is designed so that a retainer or locking mechanism can be snapped onto the platform, trapping the cornea, with simple downward pressure.  
         [0007]     The outside diameter of the platform is sized to accommodate a 13-16 mm diameter donor corneal-scleral unit. The inside diameter is sized to allow viewing of the endothelial layer of the cornea, the average diameter of which is approximately 11-12 mm. Essentially, the cornea sits on the upper surface of the platform, which also functions as part of the securing feature of the invention, by engaging a clamp and holding the cornea in position.  
         [0008]     The clamp attaches to the platform to hold the cornea in place. In this one embodiment, the clamp is generally cylindrical in shape and the cylinder has side portions that include cutaways. The cutaways provide the ability to flex the clamp and allow the movement of preservation media, which in one embodiment is a specialized cornea tissue preservative solution, into and out of the cylinder. The bottom side of the clamp includes a mating surface that is a split ring with two halves and a locking mechanism, which consists of two pawls. When the clamp is placed above the receiving surface for mating, the pawls attach on the bottom side of the receiving surface when the clamp is in the open position and the ring halves are spread apart. Each pawl then overlays, but not does not lie on top of, the receiving surface, and secures the clamp, the platform and the cornea. Ultimately, the cornea lies on the receiving surface, in between the receiving surface and the two halves of the mating surface.  
         [0009]     In another embodiment, the cornea receiving surface and the cornea mating surface are located towards a generally more central location of the apparatus. This further embodiment may provide the locking mechanism displaced downwardly away from the cornea receiving and mating surfaces. The mating surface is generally annular but it may not take the form of a split ring configuration. A stepped web portion may extend around at least a portion of the mating surface, and may include notches in the stepped web portion.  
         [0010]     In addition, a storage unit is provided, which, in one embodiment, is a glass or plastic vial into which an operator places the clamp and platform combination. The vial is filled with the preservation media and, since the vial is transparent, the cornea can be seen in the vial. The top of the vial has threads that engage a lid. The lid has an inside, outside, top and bottom and has internal threads that start at the bottom interior of the lid and go half way to the top of the lid. The lid has a flange protruding downwards from the top of the inside of the lid. The flange aids in the stabilization and securitization of the clamp-platform combination by engaging the top of the clamp so that the top of the clamp sits in the interior of the lid.  
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a perspective view of the apparatus containing a donor cornea, in accordance with a first embodiment of the present invention.  
         [0012]      FIG. 2  is an exploded view of the apparatus shown in  FIG. 1 .  
         [0013]      FIG. 3  is a perspective view of a base of the present invention as shown in  FIGS. 1 and 2 .  
         [0014]      FIG. 4  is a bottom view of the base.  
         [0015]      FIG. 5  is a side view of the base.  
         [0016]      FIG. 6  is a perspective view of the combination clamp and handle of the present invention as shown in  FIGS. 1 and 2 .  
         [0017]      FIG. 7  is a side view of the combination clamp and handle of  FIG. 6 .  
         [0018]      FIG. 8  is a side view of the lid of the present invention as shown in  FIGS. 1 and 2 .  
         [0019]      FIG. 9  is a cross-sectional view of the lid of  FIG. 8 .  
         [0020]      FIG. 10  is a bottom view of the lid of  FIG. 8 .  
         [0021]      FIG. 11  is a perspective view of the apparatus containing a donor cornea, in accordance with a further embodiment of the present invention.  
         [0022]      FIG. 12  is a perspective view of the platform and clamp of  FIG. 11 , with the donor cornea in place.  
         [0023]      FIG. 13  is a perspective view of a base or platform of the present invention as shown in  FIGS. 11 and 12 .  
         [0024]      FIG. 14  is a top view of the base, of  FIG. 11 .  
         [0025]      FIG. 15  is a bottom view of the base of  FIG. 11 .  
         [0026]      FIG. 16  is a perspective side view of the base of  FIG. 11 .  
         [0027]      FIG. 17  is a side cross section view of the base taken along line  17 - 17  of  FIG. 16 .  
         [0028]      FIG. 18  is a perspective view of the clamp of  FIG. 11 .  
         [0029]      FIG. 19  is a first side view of the clamp of  FIG. 18 .  
         [0030]      FIG. 20  is a second side view of the clamp of  FIG. 18 , but taken along the line  20 - 20  of  FIG. 19 .  
         [0031]      FIG. 21  is a side cross section view of the clamp of  FIG. 18  taken along line  21 - 21  of  FIG. 20 .  
         [0032]      FIG. 22  is a top view of the clamp of  FIG. 11 . 
     
    
     DETAILED DESCRIPTION  
       [0033]      FIG. 1  is a perspective view of the fixture  10  containing a donor cornea  12  in accordance with one embodiment of the present invention.  FIG. 2  is an exploded view of the fixture and donor cornea of  FIG. 1 .  FIG. 2  includes a vial  14 , base  16 , donor cornea  12 , combination clamp and handle  18  and a lid  20 . The vial  14  includes a cylindrical side wall  22 , an optically clear closed end  24 , an opened end  26  having external threads  28 .  
         [0034]      FIG. 3  is a perspective view of the base. The base includes an annular ring-shaped portion  30  having an upper side  32  and a lower side  34 . The upper side includes a donor cornea receiving surface  36 . The lower side includes a plurality of legs  38  depending there from. The legs are spaced apart from one another to provide adequate circulation of a fluid preservation media. The annular ring-shaped portion includes a periphery  40  having a beveled side wall  42 . The legs are spaced inwardly away from the periphery of the annular ring-shaped portion. The external wall  44  of the legs is shown to be beveled, extending downwardly and outwardly to provide a larger footprint for stability.  
         [0035]      FIG. 6  shows a perspective view of the clamp  18 . The clamp defines a generally cylindrical shape.  FIG. 7  shows the clamp includes two opposing handles or levers  50  which extend in a direction parallel to the longitudinal axis of the clamp. The lower end of the clamp includes a split ring-shaped clamp  52 . The split ring-shaped clamp includes an upper side  54  and a lower side  56 . The lower side of the split ring-shaped clamp provides a cornea mating or receiving surface  58 . Each lever includes a proximal end  60  secured to a respective portion  62  of the split ring-shaped clamp. The distal end  64  of the levers are secured together by a stabilizing mechanism in the form of a ring  66 . A portion  68  of each lever between the distal and proximal ends are connected together by means of a first and second web portion  70 .  FIG. 6  shows one web portion. The other web portion is a mirror image of the web portion shown in  FIG. 6 . Between the portion  68  and distal end  64  is an upper side wall  72 . The proximal end of the handles extend further away from the distal ends and form a locking flange  74 .  FIG. 7  shows that each locking flange includes an under cut  76  with respectively define an abutment surface  78  which extends in a plane perpendicular to the longitudinal axis of the clamp. The clamp shown in  FIG. 6  is made of a resilient material.  
         [0036]      FIG. 8  is a side view of the lid.  FIG. 9  is a cross-sectional view of the lid of  FIG. 8 .  FIG. 9  shows that the lid includes a cylindrical wall  80  and end cap  82  defining an interior compartment  84 . The interior compartment includes a thread  86  extending along the cylindrical wall. A conical shaped portion  88  extends from the end cap in a downward direction.  FIG. 10  is a bottom view of the lid of  FIG. 8  and shows the interior compartment, including the angled, conical wall  90  of the conical shaped portion and the end wall  92  of the conical shaped portion.  
         [0037]     In operation, the donor cornea  12  is placed upon the base  16 , with the endothelial layer facing the cornea receiving surface  36 . The user grasps the clamp at the upper side walls  72  of the clamp. The user presses the upper side walls together thereby causing the clamp to flex and pivot about the web portions  70  causing the split ring-shaped clamp  52  to separate and open. In this configuration, the clamp  18  is placed over the cornea  12  and base  16  with the abutment surfaces  78  extending below the lower side  34  of the base. With the clamp properly oriented with respect to the cornea and base, the pressure is removed from the upper side walls  72 , causing the locking flanges  74  to close upon the base with the abutment surfaces  78  coming into contact with the lower side  34  of the base  16 . In this manner, the clamp  18  and base  16  securely lock the cornea  12  there between.  
         [0038]     The combination clamp base and cornea are then placed into the vial  14  having a fluid preservation media. The legs of the base rest upon the optically clear closed end of the vial. The lid is then threaded onto the open end of the vial, with the conical shaped portion coming into contact with the ring-shaped stabilizing mechanism, thereby securing the clamp and securing the clamp and base between the lid and the closed end of the vial. This arrangement prevents the assembly from moving out of position for viewing in the vertical position for cell counting of the endothelia layer and also in the horizontal position for slit lamp inspection of the cornea.  
         [0039]     Later, at point of use, the lid is removed from the vial and the assembly is removed from the vial and placed on its feet in the sterile field. At this time, the flexible upper side walls of the levers are squeezed inward to remove the locking feature of the locking flanges and allowing the removal of the clamp. The donor cornea is now resting on the base of the unit with the endothelial side of the cornea fully protected and not in contact with any surface. The corneal-scleral unit is now available for use in the transplant procedure.  
         [0040]     The apparatus of the present invention secures the donor cornea in a vial for ease of access and to allow removal of the donor cornea without risk of damage to the donor cornea. The fixture allows for optical examination without removing the donor cornea from the vial. The fixture also allows for easy and safe retrieval of the donor cornea by the transplant surgeon. This eliminates risk of damage and eliminates the need to transfer the donor cornea into a fresh vial of preservation media.  
         [0041]      FIGS. 11-22  show another embodiment. Features which are similar to those of the first embodiment are identified with the corresponding reference numeral.  FIG. 16  shows that the leg or legs  38  of the base  16  are essentially an extension of the beveled side wall  42 . It will be appreciated that the embodiment of  FIGS. 11-22  provide greater stability than the embodiment of  FIGS. 1-10 . It will also be appreciated from  FIGS. 11-22 , particularly from  FIGS. 11 and 12 , that the further embodiment raises the cornea receiving surface  36  a greater distance from the end  24  of the vial  14 , in comparison to the first embodiment. Thus, the cornea is elevated from suspended particulate which may collect or accumulate at or near the end  24 , with the vial  14  in the upright position.  
         [0042]      FIGS. 18-21  show that the distal end  64  of the handles or levers  50  do not extend up to ring  66 . The distal ends  64  stop short of the ring  66 . Instead, four structures  100  extend downwardly from the ring  66  from a first end  102 . The second end  104  of the structures  100  connect to the cornea mating surface  58  via a stepped web portion  106  extending from either side of the handles or levers  50 .  FIG. 20  shows that the two structures  100  which connect at either side of a respective lever  50  are spaced apart from one another and the respective lever  50 . An opening  108  is defined by the two structures  100  shown in  FIG. 20 .  FIGS. 19 and 21  show that two structures  100  which connect to opposing levers  50 , define an opening  110  having an enlarged cutout  112  which extends downward to the cornea mating surface  58 . The combination clamp and handle  18  of  FIGS. 11-22  is designed to enhance a bellow like compression upon securing the lid  20  to the vial  14 , with the downwardly movement of the conical wall  90  upon the ring  66 . Extended arms  114  of the levers  50  include the locking flange  74  and operate independent from the compression action of the structures  100  and stepped web portion  106 .  
         [0043]     With reference particularly to  FIGS. 1 and 11 , it will be appreciated that, in one embodiment, the dimension of the fixture and vial are selected to provide a focal length appropriate for a microscope viewing the cornea  12  through the end  24  of the vial  14 .