Device for postoperative fixation back into the cranium of a plug of bone removed therefrom during a surgical operation

Abstract

A device for rapid reattachment of a bone flap to a cranium after a surgical operation is provided. The device comprises a pin comprising an elongated shaft, an inner disk and an outer disk. At least the outer disk comprises a central bore. The pin and inner disk are adapted to be assembled together to form a pin and inner disk assembly such that the inner disk is located at one end of the pin. The outer disk is adapted to be mounted on the shaft of the pin with the shaft of the pin extending through the central bore of the outer disk. The device is operated by (i) positioning the inner disk on the inside of the cranium with the shaft of the pin extending through the kerf between the bone flap and the cranium, (ii) forcing the outer disk downwardly on the shaft of the pin toward the inner disk until the outer disk securely engages the outside of the bone flap and the cranium, such that the bone flap is securely held in place between the inner disk and the outer disk, and (iii) trimming off an excess portion of the shaft extending out beyond the outer disk.

1 . A device for postoperative fixation back into an opening in the cranium of a plug of bone removed therefrom during a surgical operation, wherein the plug is to be repositioned in the opening such that the space between the plug and the surrounding cranial bone is approximately the width of the kerf formed during the surgical operation and the internal and external surfaces of the plug are to be held in alignment with the adjacent internal and external surfaces of the surrounding cranial bone, the device comprising the following elements formed of a physiologically compatible substance: 
 a pin having a shaft that is extendable through the space between the plug and the surrounding cranial bone, the shaft having a proximal end and a distal end;    a substantially rigid first disk mounted centrally on the shaft of the pin at the proximal end, the first disk having an inner surface oriented toward the distal end of shaft and an opposite outer surface, the first disk being positionable interiorly of the opening in the cranium such that the inner surface faces the internal surface of the plug and the adjacent internal surface of the surrounding cranial bone;    a substantially rigid second disk mounted centrally on the shaft of the pin at the distal end, the second disk having a bore formed therein through which the shaft of the pin extends, an inner surface facing the first disk, and an opposite outer surface, the second disk being positionable exteriorly of the opening in the cranium such that the inner surface faces the external surface of the plug and the adjacent external surface of the surrounding cranial bone, the second disk being movable along the shaft towards the first disk from a first position wherein the first or the second disk is out of engagement with the plug and surrounding cranial bone to a second position wherein the first and second disks engage and align the internal and external surfaces of the plug and surrounding cranial bone; and    means for retaining the second disk in the second position.    
     
     
         2 . A device in accordance with  claim 1  wherein the first disk includes teeth formed on the periphery thereof that extend toward the second disk.  
     
     
         3 . A device in accordance with  claim 1  wherein the second disk includes teeth formed on the periphery thereof that extend toward the first disk.  
     
     
         4 . A device in accordance with  claim 1  wherein the retaining means comprises notches formed along at least a portion of the length of the shaft of the pin, the notches restraining movement of the second disk along the shaft in the direction opposite the first disk.  
     
     
         5 . A device in accordance with  claim 1  wherein the bore of the second disk is sized so as to fit snugly around the shaft, and said retaining means comprises frictional engagement between the second disk and the shaft.  
     
     
         6 . A device in accordance with  claim 1  wherein the pin has a substantially flat head formed at the proximal end of the shaft, the first disk includes a bore through which the shaft extends, and the outer surface of said first disk rests against the head.  
     
     
         7 . A device in accordance with  claim 1  wherein each of the first and second disks is concavoconvex in shape and each is oriented on the shaft such that its inner surface is the concave side.  
     
     
         8 . A device in accordance with  claim 7  wherein each of the first and second disks is deformed in its center in a direction opposite its concavoconvexity.  
     
     
         9 . A device as defined in  claim 1 , wherein said physiologically compatible substance is a metallic substance.  
     
     
         10 . A device in accordance with  claim 1 , wherein said first disk includes perforations uniformly distributed within the area of said first disk between the center and the circumference of said first disk.  
     
     
         11 . A device according to  claim 1 , wherein said second disk includes perforations uniformly distributed within the area of said second disk between the center and the circumference of said second disk.