Spinal compression and distraction devices and surgical methods

Abstract

A spinal distraction device is provided that includes a body, a rack and a pinion-locking member. The body has a vertebral endplate engagement end and an opposite end. The body defines a chamber along its length and an opening at the opposite end in communication with the chamber. A gear bore is defined in communication with the chamber and has an axis perpendicular to the length. The rack is slidably disposed through the opening and within the chamber. The rack is slidable between a retracted position with the first end of the rack adjacent the vertebral engaging end of the body and the foot adjacent the opposite end of the body and a number of extended positions wherein the foot is at a distance from the opposite end of the body. The rack defines an engagement member with an engagement surface exposed to the gear bore. The pinion-locking member is rotatable within the gear bore to mesh with the engagement surface to convert rotary motion of the member to reciprocating motion of the rack. The member also includes a locking portion at one end of the member, which prevents rotation of the member within the gear bore. The member is slidable between a pinion position in which the pinion portion is disposed within the gear bore and a locked position in which the locking portion is disposed within the gear bore. The member is preferably biased to the locked position.