Plate for covering a drill hole in a skull cap and for fixing a cranial bone cover

Abstract

A plate for covering a drill hole in a skull cap and for fixing a cranial bone cover comprises a plurality of vanes ( 16 a -16 e ) extending radially with respect to a center ( 12 ) and slots ( 20 a -20 e ) between the vanes. For receiving bone screws holes ( 18 a -18 e ) are provided in the respective region of the outer periphery of the vanes.

We claim:  
     
       1. A cranial implant for fixation to the cranial vault of a bone cover,  of a bone cover to the cranial vault, said bone cover being previously removed from said cranial vault by a procedure including drilling of at least one hole in said cranial vault at an edge of the bone cover, and for covering the drill hole, said implant comprising: 
       a plate formed of a body-compatible metal which is rotational-symmetrical with respect to a center and has a plurality of vanes which extend radially with respect to said center and are separated from each other by slots for providing visibility of at least some of the skull area  drill hole beneath a  said plate being implanted, at least some of said vanes each having a hole at its outer peripheral portion for receiving a bone screw, with said plate being adapted for centering over a drill hole during implentation  implantation whereby the holes in said vanes are so positioned relative to the drill hole that bone screws received through the holes are adapted to screw the plate to said bone cover and cranial vault surrounding the drill hole and thereby fix the bone cover to the cranial vault, wherein said plate has a central hole formed therein concentric with the center of said plate, and said plate has a plurality of holes therethrough, distributed around said central hole, for allowing blood and other fluids to flow through the plate following fixation of the cranial bone cover.  
     
     
       2. A cranial implant according to claim  1 , wherein the holes in said at least some vanes for receiving respective bone screws are arranged on a circle centered at said center of said plate. 
     
     
       3. A cranial implant according to claim  2   1 , wherein each hole for receiving a respective bone screw is located centrally onin a vane integral projection extending beyond the outer edge of the peripheral portion of a respective vane. 
     
     
       4. A cranial implant according to claim  3 , wherein each of said vanes has an integral ring formed centrally on said vane integral projection extending beyond the outer peripheral portion thereof and having a centrally located hole formed therein for receiving a respective bone screw. 
     
     
       5. A cranial implant according to claim  2   1 , wherein each of said vanes has a ring formed atin an integral projection extending beyond the outer peripheral portion thereof and having a centralcentrally located hole formed therein for receiving a respective bone screw. 
     
     
       6. A cranial implant according to claim  5 , wherein the slots separating said vanes from each other extend radially with respect to the center of said plate over substantially the outer half of the radius of said plate to enable visual centering of said plate over said drill hole. 
     
     
       7. A cranial implant according to claim  6 , wherein said plate has a central hole formed therein concentric with the center of said plate. 
     
     
       8. A cranial implant according to claim  7 , wherein said plate has a plurality of holes therethrough, distributed around said central hole, for allowing blood and other fluids to flow through the plate following fixation of the cranial bone cover. 
     
     
       9. A cranial implant according to claim  1 , wherein each of said vanes has a ring formed at  in an integral projection extending beyond the outer peripheral portion thereof and having a hole formed therein for receiving a respective bone screw. 
     
     
       10. A cranial implant according to claim  1 , wherein the slots separating said vanes from each other extend radially with respect to the center of said plate. 
     
     
       11. A cranial implant according to claim  10 , wherein the slots separating said vanes extend radially over substantially the outer half of the radius of said plate. 
     
     
       12. A cranial implant according to claim  11 , wherein said slots are conical tapered radially inwardly, being widest at their outer extremity. 
     
     
       13. A cranial implant according to claim  11 , wherein said slots are conically tapered radially inwardly, being widest at their outer extremity. 
     
     
       14. A cranial implant according to claim  1 , wherein said plate has an odd number of vanes. 
     
     
       15. A cranial implant according to claim  1 , wherein said plate has five vanes rotational-symmetrical with respect to the center of said plate. 
     
     
       16. A cranial implant according to claim  1 , wherein said plate is normally flat but is permanently deformable to the contour of the skull. 
     
     
       17. A cranial implant according to claim  1 , wherein said plate is shaped during manufacture to have a concavely curved bottom surface. 
     
     
       18. A cranial implant for fixation of a bone cover to the cranial vault to cover an open area caused by previously removed bone by a procedure including drilling at least one hole at an edge of the bone cover, said implant comprising: 
         a plate formed of a body - compatible metal;    
       
         a plurality of vanes extending radially from said plate;  
       
       
         said vanes being separated from each other by slots, said slots being of sufficient length for providing visibility of at least some of said drill hole beneath said plate being implanted;  
       
       
         a hole in an outer portion of at least some of said vanes for receiving a bone screw;  
       
       
         said plate being adapted for centering over said drill hole whereby the holes in said vanes are positioned relative to the drill hole so that bone screws received through the holes are adapted to screw the plate to said bone cover and said cranial vault surrounding the drill hole and thereby fix said bone cover to the cranial vault; and  
       
       
         a plurality of holes in said plate distributed around a center of said plate for allowing blood and other fluids to flow through said plate following fixation of the cranial bone cover. 
       
     
     
       19. A cranial implant according to claim  18 , wherein the holes in said at least some vanes for receiving respective bone screws are arranged on a circle centered at said center of said plate. 
     
     
       20. A cranial implant according to claim  18 , wherein the slots separating said vanes from each other extend radially with respect to the center of said plate over substantially the outer half of the radius of said plate. 
     
     
       21. A cranial implant according to claim  18 , wherein said plate has a central hole formed therein concentric with the center of said plate. 
     
     
       22. A cranial implant according to claim  18 , wherein said plate has an odd number of vanes. 
     
     
       23. A cranial implant according to claim  18 , wherein said plate is normally flat but is permanently deformable to the contour of the skull. 
     
     
       24. A cranial implant according to claim  18 , wherein said plate is shaped during manufacture to have a concavely curved bottom surface. 
     
     
       25. A cranial implant according to claim  18 , wherein each hole for receiving a respective bone screw is located centrally in a vane integral projection extending beyond the outer peripheral portion of a respective vane. 
     
     
       26. A cranial implant according to claim  18 , wherein each of said vanes has a ring formed in an integral projection extending beyond the outer portion thereof and having a hole formed therein for receiving a respective bone screw. 
     
     
       27. A method of covering a drill hole in the cranial vault of a patient, said method comprising the steps of: 
         forming a plate of body - compatible metal having a main body portion and that is rotationally symmetrical with respect to a center of said plate;    
       
         forming a plurality of vanes extending from said main body;  
       
       
         forming at least one of said openings in an integral projection extending beyond the outer edge of each of said vanes for receiving said bone screws;  
       
       
         substantially covering said drill hole with said main body portion of said plate; and  
       
       
         attaching said plate to said cranial vault with bone screws received through said plurality of openings. 
       
     
     
       28. The method of claim  27  wherein said main body would cover a drill hole of approximately  7  millimeters wide. 
     
     
       29. The method of claim  27  wherein said main body would cover a drill hole of approximately  14  millimeters wide. 
     
     
       30. The method of claim  27  further including the step of forming an opening in a central portion of said main body. 
     
     
       31. The method of claim  27  further including the step of forming a plurality of openings in said main body for allowing blood and other fluids to flow through said plate following attachment to the cranial vault.