The results at 6 months are less clear than those at 12 months. The results at 12 months for the experimental group are (1) the intervertebral disc height decreased at the caudad adjacent level and to a lesser extent at the cephalad adjacent level; (2) the MRI scores for the discs at the caudad and cephalad adjacent levels showed severe loss of signal intensity as compared to the discs at the same levels in the control group