Cranial bone flap fixation system and method

Abstract

A cranial bone and bone flap fixation device, comprising first and second caps between which portions of the cranial bone and bone flap are to be gripped; a mounting post located to allow relative cap movement lengthwise of an axis defined by the post, at least the first cap, which is movable lengthwise of the post, forming peripheral petals that are spaced apart about an axis and radially outwardly of a central body portion of the cap, whereby the petals are individually and resiliently movable relative to the central body portion in directions generally parallel to the axis, and in response to gripping.

1 . A cranial bone and bone flap fixation device, comprising 
 a) first and second caps between which portions of the cranial bone and bone flap are to be gripped,    b) a mounting post located to allow relative cap movement lengthwise of an axis defined by the post,    c) at least the first cap forming peripheral petals that are spaced apart about said axis and radially outwardly of a central body portion of the cap, whereby the petals are individually and resiliently movable relative to said central body portion in directions generally parallel to said axis, and in response to said gripping, said first cap being movable lengthwise of the post.    
   
   
       2 . The device of  claim 1  wherein said petals have widths which decrease in directions toward said axis to define flexure zones spaced between said axis and portions of the petals furthest from said axis.  
   
   
       3 . The device of  claim 1  wherein said petals have flexure zones spaced between said axis and portions of the petals furthest from said axis.  
   
   
       4 . The device of  claim 1  wherein said petals are one of the following: 
 i) metallic    ii) non-metallic.    
   
   
       5 . The device of  claim 1  wherein said petals consist essentially of titanium, titanium alloy, or other bio-compatible material.  
   
   
       6 . The device of  claim 1  wherein each of said first and second caps has peripheral petals as defined in sub-paragraph c) of  claim 1 .  
   
   
       7 . The device of  claim 1  wherein one of the caps is attached to an end of the post, and the other cap is adjustably movable along said post toward said one cap, the petals of each cap having peripheral portions angled toward the other cap.  
   
   
       8 . The device of  claim 7  wherein the post has axially spaced retention shoulders, and the other cap has tabs spaced about and projecting toward said axis, and which have ratcheting engagement with said shoulders as said other cap is moved toward said one cap, said retention shoulders angled to unidirectionally lock to the tabs.  
   
   
       9 . The device of  claim 8  wherein said tabs are spaced about said axis, and are individually resiliently flexible in directions generally parallel to said axis.  
   
   
       10 . The device of  claim 8  wherein said tabs have widths less than their lengths, and define tips that have said ratcheting engagement with said shoulders.  
   
   
       11 . The device of  claim 8  wherein the number of said tabs is less than the number of said petals.  
   
   
       12 . A cranial bone and bone flap fixation device, comprising 
 a) first and second caps between which portions of the cranial bone and bone flap are to be gripped,    b) a mounting post located to allow relative cap movement lengthwise of an axis defined by the post,    c) one of the caps being attached to an end of the post, the other cap being movable along the post toward said one cap,    d) the post having axially spaced retention shoulders, and the other cap has spaced tabs projecting toward said axis, and which have ratcheting engagement with said shoulders as said other cap is moved toward said one cap, said shoulders configured for blocking retraction of said other cap lengthwise of the post.    
   
   
       13 . The device of  claim 12  wherein said tabs are spaced about said axis, and are individually resiliently flexible in directions generally parallel to said axis.  
   
   
       14 . The device of  claim 12  wherein said tabs have widths less than their lengths, and define tips that have said ratcheting engagement with said shoulders.  
   
   
       15 . The method of affixing a bone flap to an adjacent cranial zone, that includes 
 a) providing first and second caps between which portions of the cranial bone and bone flap are to be gripped,    b) providing a mounting post located to allow relative cap movement lengthwise of an axis defined by the post,    c) providing at least the first cap with peripheral petals that are spaced apart about said axis and radially outwardly of a central body portion of the cap, whereby the petals are individually and resiliently movable relative to said central body portion in directions generally parallel to said axis, and in response to said gripping,    d) relatively displacing the caps toward one another to engage the petals of one cap with at least the bone flap or the adjacent cranial bone, and to conformingly retain the caps including said petals to opposite sides of the flap and the cranial bone,    e) tightening the caps relatively toward one another into positions wherein relative separation of the caps is blocked, petals are resiliently flexed, and post extent between the caps is tensioned, the lower cap pulled in an upward direction as the upper cap is tightened downwardly.    
   
   
       16 . The device of  claim 1  including a protruding guide on at least one of said caps and configured to extend into a gap formed between the cranial bone and bone flap, to laterally orient the one cap so that petal portions thereof will lap, to approximately equal lateral extents, adjacent cranial bone and bone flap surfaces.  
   
   
       17 . The device of  claim 16  wherein said guide has an axially tapering surface to project into the gap between edges of said cranial bone and bone flap.  
   
   
       18 . The device of  claim 17  including a cover extending over a cavity formed by said protruding guide, and attached to said one cap.  
   
   
       19 . The device of  claim 16  wherein said guide has cup-shape.  
   
   
       20 . The device of  claim 16  wherein said protruding guide comprises guide tabs that are bent to protrude into said gap, said tabs spaced about said axis.  
   
   
       21 . The device of  claim 12  including a protruding guide on at least one of said caps and configured to extend into a gap formed between the cranial bone and bone flap, to laterally orient the one cap so that petal portions thereof will lap to approximately equal lateral extents adjacent cranial bone and bone flap.  
   
   
       22 . The device of  claim 21  wherein said guide has an axially tapering surface or surfaces to project into the gap between edges of said cranial bone and bone flap.  
   
   
       23 . The device of  claim 22  including a cover extending over a cavity formed by said protruding guide, and attached to said one cap.  
   
   
       24 . The device of  claim 21  wherein said protruding guide has cup-shape.  
   
   
       25 . The device of  claim 21  wherein said protruding guide comprises guide tabs that are bent to protrude into said gap, said tabs spaced about said axis.  
   
   
       26 . The method of  claim 15  wherein at least one of the caps has a protruding guide thereon, and including the step of causing said guide to orient the cap transversely as the cap petals approach or engage bone flap and cranial bone surfaces.  
   
   
       27 . A cranial bone and bone flap fixation device, comprising 
 a) first and second caps between which portions of the cranial bone and bone flap are to be gripped,    b) a mounting post located to allow relative cap movement lengthwise of an axis defined by the post,    c) and including a protruding guide on one of said caps and configured to extend into a gap formed between the cranial bone and bone flap, to laterally orient the one cap so that an outer portion thereof will lap, to approximately equal lateral extent, adjacent cranial bone and bone flap surfaces.    
   
   
       28 . The device of  claim 27  wherein said guide has an axially tapering surface to project into the gap between edges of said cranial bone and bone flap.  
   
   
       29 . The device of  claim 28  including a cover extending over a cavity formed by said protruding guide, and attached to said one cap.  
   
   
       30 . The method of affixing a bone flap to an adjacent cranial zone, that includes 
 a) providing first and second caps between which portions of the cranial bone and bone flap are to be gripped,    b) providing a mounting post located to allow relative cap movement lengthwise of an axis defined by the post,    c) relatively displacing the caps toward one another to first engage one cap with the underside of at least the bone flap or the adjacent cranial bone,    d) and then tightening the caps relatively toward one another into positions wherein relative separation of the caps is blocked, the lower cap pulled upwardly as the upper cap is tightened downwardly.    
   
   
       31 . The method of  claim 30  including providing a protruding guide on at least one of said caps and configured to extend into a gap formed between the cranial bone and bone flap, to laterally orient the one cap to have approximately equal lateral extents thereof adjacent cranial bone and bone flap surfaces.  
   
   
       32 . The method of  claim 31  wherein said guide is provided with an axially tapering surface to project into the gap between edges of said cranial bone and bone flap.