Abstract: A spinal distraction apparatus has a distraction rod extending along an axis and having in turn a center part, a pair of end parts secured in, extending axially oppositely from, and rotatable about the axis relative to the center part, and a screwthread connection between each of the end parts and the center part. The screwthread connections are of opposite hand so that rotation of the center part in one direction moves the end parts axially toward each other and opposite rotation moves them axially apart. The end parts are axially nondisplaceable relative to the center part except on rotation of same about the axis. Respective anchors axially nondisplaceable on the end parts are adapted to be secured to respective vertebra. Formations between the anchors and the respective end parts prevent rotation of the end parts about the axis relative to the anchors.