Apparatus and method for body tissue fixation

Abstract

A body tissue fixation apparatus includes a plate having oppositely disposed outer and tissue-contacting surfaces, and at least one fixation hole extending between the outer and tissue-contacting surfaces along a longitudinal axis. The fixation hole is defined in part by an inner hole surface having at least one serration. The plate is adapted for affixation to at least one body tissue member. At least one fixation device of the body tissue fixation apparatus has a shank and a head portion, the shank being insertable through the fixation hole in the plate to affix the plate to the body tissue member upon rotation of the head portion. At least one deformable member is connected to the head portion, the deformable member extending laterally in a direction substantially perpendicular to the longitudinal axis and being adapted to deflect to engage with at least one serration formed on the inner hole surface. Engagement between the deformable member and the serration helps to prevent displacement of the fixation device within the fixation hole. A method for using the body tissue fixation apparatus is also described.

1 - 21 . (canceled) 
     
     
         22 . A method for securing a plate to a body tissue of a patient, the method comprising the steps of:
 providing a plate having oppositely disposed outer and tissue-contacting surfaces and at least one fixation hole extending between the outer and tissue-contacting surfaces along a longitudinal axis, the fixation hole being defined in part by an inner hole surface having at least one serration;   placing the plate into a desired orientation with the body tissue;   providing at least one fixation device having a shank with spaced-apart first and second shank ends separated along the longitudinal axis, the fixation device having a head portion having top and bottom surfaces spaced apart by a main body, the first shank end extending from the bottom surface, the head portion including at least one void extending longitudinally through the main body between the top and bottom head surfaces to define at least one deformable member extending from the main body;   inserting the second shank end into the fixation hole and into engagement with the body tissue;   rotating the head portion to cause the shank to sink into the body tissue and the head portion to engage the plate;   deflecting the deformable member away from an initial position; and   engaging a serration with the deformable member to help prevent the fixation device from displacement within the fixation hole.   
     
     
         23 . The method of  claim 22 , wherein at least one serration on the inner hole surface is oriented in at least one of a lateral direction, a circumferential direction, and a longitudinal direction around the fixation hole. 
     
     
         24 . The method of  claim 22 , wherein the step of rotating the head portion includes the steps of:
 engaging the head portion with an insertion tool; and   actuating the insertion tool to drive the shank into the body tissue.   
     
     
         25 . The method of  claim 22 , wherein the step of rotating the head portion includes rotation in a first direction, and the step of engaging a serration with the deformable member helps prevent the fixation device from rotation within the fixation hole in a second direction opposite the first direction. 
     
     
         26 . The method of  claim 22 , including the steps of:
 engaging the head portion with a removal tool;   deflecting the deformable member toward the longitudinal axis with the removal tool; and   rotating the head portion to cause the shank to draw away from the body tissue and the head portion to disengage from the plate.   
     
     
         27 . The method of  claim 22 , including the step of selectively interlocking a blocking notch on a chosen one of the plate and the fixation device and a blocking lug on the other one of the plate and the fixation device responsive to a predetermined amount of rotation of the fixation device in a first direction about the longitudinal axis, the interlocking of the blocking notch and blocking lug being operative to substantially prevent at least one of further rotation of the fixation device in the first direction and longitudinal motion of the fixation device with respect to the plate. 
     
     
         28 . The method of  claim 22 , including the step of exerting a longitudinal spring force between the deformable member and the plate to hold the fixation device in longitudinal contact with the plate. 
     
     
         29 . A body tissue fixation apparatus, comprising:
 a plate having oppositely disposed outer and tissue-contacting surfaces, and at least one fixation hole extending between the outer and tissue-contacting surfaces along a longitudinal axis, the fixation hole being defined in part by an inner hole surface, the plate being adapted for affixation to at least one body tissue member;   at least one fixation device having a shank and a head portion, the shank being insertable through the fixation hole in the plate to affix the plate to the body tissue member upon rotation of the head portion; and   the plate including a chosen one of a blocking notch and a blocking lug, and the fixation device including the other one of the blocking notch and the blocking lug, the blocking notch and blocking lug selectively interlocking responsive to a predetermined amount of rotation of the fixation device in a first rotation direction about the longitudinal axis; wherein   the interlocking of the blocking notch and blocking lug is operative to substantially prevent at least one of further rotation of the fixation device in the first rotation direction and longitudinal motion of the fixation device with respect to the plate.   
     
     
         30 . The body tissue fixation apparatus of  claim 29 , wherein the blocking lug prevents the fixation device from insertion to a maximum desired engagement position within the fixation hole unless the fixation device is registered by at least one of the blocking notch and the blocking lug into a predetermined orientation with respect to the fixation hole during rotation of the fixation device in the first direction. 
     
     
         31 . A body tissue fixation apparatus, comprising:
 a plate having oppositely disposed outer and tissue-contacting surfaces, and at least one fixation hole extending between the outer and tissue-contacting surfaces along a longitudinal axis, the fixation hole being defined in part by an inner hole surface having at least one serration;   the plate being adapted for affixation to at least one body tissue member;   at least one fixation device having a shank and a head portion, the shank being insertable through the fixation hole in the plate to affix the plate to the body tissue member upon rotation of the head portion; and   at least one deformable member formed as a single piece with the head portion, the deformable member extending laterally in a direction substantially perpendicular to the longitudinal axis and being adapted to engage with at least one serration formed on the inner hole surface, wherein engagement between the deformable member and the serration helps to prevent displacement of the fixation device within the fixation hole.