Method and apparatus for providing a retainer for a bone stabilization device

Abstract

A skeletal fixation apparatus includes: a plate having first and second spaced apart surfaces and a plurality of apertures extending through the surfaces of the plate, each aperture for receiving a respective fixation element for coupling the plate to one or more bones of a patient; and at least one retention element having an elongate member coupled to the plate at first and second ends thereof, wherein the first end of the elongate member is fixed in position and the second end of the elongate member is operable to rotate about the first end such that: (i) at least a portion of the elongate member overlies at least a portion of a first of the apertures when the second end is in at least one first rotational position to retain a first fixation element in the first aperture, and (ii) the elongate member does not substantially overlie the first aperture when the second end is in at least one second rotational position to permit the first fixation element to enter or exit the first aperture.

1 . A skeletal fixation apparatus, comprising: 
 a plate having first and second spaced apart surfaces and a plurality of apertures extending through the surfaces of the plate, each aperture for receiving a respective fixation element for coupling the plate to one or more bones of a patient; and    at least one retention element having an elongate member coupled to the plate at first and second ends thereof,    wherein the first end of the elongate member is fixed in position and the second end of the elongate member is operable to rotate about the first end such that: (i) at least a portion of the elongate member overlies at least a portion of a first of the apertures when the second end is in at least one first rotational position to retain a first fixation element in the first aperture, and (ii) the elongate member does not substantially overlie the first aperture when the second end is in at least one second rotational position to permit the first fixation element to enter or exit the first aperture.    
   
   
       2 . The apparatus of  claim 1 , wherein the second end of the elongate member is biased toward the first rotational position.  
   
   
       3 . The apparatus of  claim 1 , wherein the first end of the elongate member is coupled to the plate such that rotation of the second end of the elongate member toward the second rotational position causes a counter torsional force urging the second end of the elongate member toward the first rotational position.  
   
   
       4 . The apparatus of  claim 3 , wherein the first end of the elongate member is rigidly fixed to the plate and the counter torsional force is developed as a result of elastic material properties of the elongate member.  
   
   
       5 . The apparatus of  claim 3 , wherein the first end of the elongate member is rotationally fixed to the plate and the counter torsional force is developed as a result of elastic material properties of the elongate member as it bends and rotates about the first end.  
   
   
       6 . The apparatus of  claim 1 , wherein the second end of the elongate member is slidingly coupled to the plate.  
   
   
       7 . The apparatus of  claim 6 , further comprising a slot extending from the first surface and at least partially through the plate, wherein the second end of the elongate member is slidingly engaged in the slot.  
   
   
       8 . The apparatus of  claim 7 , wherein the slot extends longitudinally along an arc having a fulcrum thereof substantially where the first end of the elongate member connects to the plate, such that the second end of the elongate member slides along the arc as it rotates between the first and second rotational positions.  
   
   
       9 . The apparatus of  claim 7 , wherein the slot extends through the plate from the first surface to the second surface and the second end of the elongate member extends through the slot at least toward the second surface of the plate.  
   
   
       10 . The apparatus of  claim 9 , further comprising a recess extending from the second surface of the plate toward the first surface thereof, and communicating with the slot, such that the second end of the elongate member slidingly engages the recess as it rotates.  
   
   
       11 . The apparatus of  claim 10 , wherein the second end of the elongate member does not extend beyond the second surface of the plate.  
   
   
       12 . The apparatus of  claim 10 , wherein: 
 a first length of the second end of the elongate member extends transversely from the portion thereof overlying the aperture as it passes through the slot; and    a second length of the second end of the elongate member extends transversely from the first length to engage the recess such that the second end of the elongate member cannot disengage from the slot.    
   
   
       13 . The apparatus of  claim 10 , wherein: 
 the first fixation element is a bone screw having a head and the portion of the elongate member overlying the first aperture permits the head to engage a periphery of the first aperture when it is in the second rotational position; and    the portion of the elongate member overlying the first aperture prevents the head from disengaging the periphery of the first aperture when it is in the first rotational position.    
   
   
       14 . The apparatus of  claim 13 , wherein: 
 the elongate member is positioned off center relative to the aperture such that the head urges the elongate member aside thereby rotating the second end thereof to the second rotational position as the bone screw is driven into the bone toward the periphery of the first aperture; and    the elongate member rotates back to the first rotational position when the head of the bone screw clears the elongate member and engages the periphery of the first aperture.    
   
   
       15 . The apparatus of  claim 1 , comprising a respective retention element disposed at each of the plurality of apertures.  
   
   
       16 . The apparatus of  claim 1 , wherein at least some of the apertures are substantially round.  
   
   
       17 . The apparatus of  claim 1 , wherein at least some of the apertures are elongate.  
   
   
       18 . The apparatus of  claim 1 , wherein the plate is of a length sufficient to extend over an intervertebral space of the patient's spine and includes at least one aperture, and associated retention element, at respective longitudinal ends thereof for coupling the plate to respective vertebral bones.  
   
   
       19 . The apparatus of  claim 1 , wherein the plate is of a length sufficient to extend over a plurality of intervertebral spaces of the patient's spine and includes at least one aperture, and associated retention element, at respective longitudinal positions thereof for coupling the plate to respective vertebral bones.  
   
   
       20 . A skeletal fixation apparatus, comprising: 
 a plate having first and second spaced apart surfaces and at least first and second apertures extending through the surfaces of the plate, each aperture for receiving a respective fixation element for coupling the plate to one or more bones of a patient; and    at least one retention element having an elongate member coupled to the plate at least at a first end, a plurality of intermediate positions, and a second end thereof, wherein:    the plurality of intermediate positions of the elongate member include at least a first intermediate position and a second intermediate position that are fixed in position, and the first and second ends of the elongate member are operable to rotate about the respective first and second intermediate positions such that: 
 (i) at least first and second portions of the elongate member overlie portions of the first and second apertures, respectively, when the respective first and second ends are in one or more first rotational positions, respectively, to retain respective fixation elements in the first and second apertures, and  
 (ii) the first and second portions of the elongate member do not substantially overlie the first and second apertures, respectively, when the first and second ends are in one or more second rotational positions, respectively, to permit the fixation elements to enter or exit the first and second apertures.  
   
   
   
       21 . The apparatus of  claim 20 , wherein: 
 the elongate member, between the first end and the first intermediate position, extends along the first surface of the plate;    the elongate member, between the first and second intermediate positions, extends along the second surface of the plate; and    the elongate member, between the second intermediate position and the second end, extends along the second surface of the plate.    
   
   
       22 . The apparatus of  claim 20 , wherein the elongate member is formed from a contiguous piece of wire.  
   
   
       23 . The apparatus of  claim 20 , further comprising at least first and second slots disposed at the first and second ends of the elongate member, respectively, each slot extending from the first surface and at least partially through the plate, wherein the first and second ends of the elongate member are slidingly engaged in the first and second slots, respectively.  
   
   
       24 . The apparatus of  claim 23 , wherein: 
 the first and second slots extend longitudinally along respective arcs, the arcs having fulcrums substantially where the first and second intermediate positions, respectively, connect to the plate; and    the first and second ends of the elongate member slide along the arcs, respectively, as they rotate between the first and second rotational positions.    
   
   
       25 . The apparatus of  claim 24 , wherein: 
 the first and second slots extend through the plate from the first surface to the second surface; and    the apparatus further comprises first and second recesses extending from the second surface of the plate toward the first surface thereof, and each communicating with one of the first and second slots, such that the first and second ends of the elongate member slidingly engage the first and second recesses, respectively, as they rotate.    
   
   
       26 . The apparatus of  claim 25 , wherein: 
 a first length of each of the first and second ends of the elongate member extends transversely from the portion thereof overlying the respective first and second apertures as it passes through the respective first and second slot; and    a second length of each of the first and second ends of the elongate member extend transversely from the first length to engage the respective first and second recesses such that the first and second ends of the elongate member cannot disengage from the first and second slots.    
   
   
       27 . The apparatus of  claim 26 , wherein: 
 the elongate member, between the first end and the first intermediate position, extends along the first surface of the plate;    the elongate member, between the first and second intermediate positions, extends along the second surface of the plate; and    the elongate member, between the second intermediate position and the second end, extends along the second surface of the plate.    
   
   
       28 . The apparatus of  claim 27 , wherein the elongate member is formed from a contiguous piece of wire.  
   
   
       29 . A tool for turning a bone screw, comprising: 
 a shaft having a first end and a second end, the second end operable to engage a head of the bone screw;    a sleeve having a first end and a second end and including a longitudinal bore sized and shaped to receive the shaft such that the shaft may rotate within and slide therethrough,    wherein the second end of the sleeve includes an engagement element operable to manipulate a bone screw retention element of a skeletal fixation apparatus while the second end of the shaft engages the head of the bone screw.    
   
   
       30 . The tool of  claim 29 , wherein the engagement element includes a tapered surface extending from an outer surface of the sleeve toward the second end of the sleeve.  
   
   
       31 . The tool of  claim 30 , wherein rotation of the sleeve about the shaft causes the tapered surface of the engagement element to urge the retention element of the skeletal fixation apparatus into a position to permit the bone screw to release from or be retained by the engagement element.  
   
   
       32 . The tool of  claim 29 , wherein rotation of the sleeve about the shaft causes the engagement element to urge the retention element of the skeletal fixation apparatus into a position to permit the bone screw to release from or be retained by the engagement element.  
   
   
       33 . The tool of  claim 32 , wherein the first end of the sleeve includes a thumb wheel operable to permit ease in rotating the sleeve about the shaft.