Anterior versus combined anterior and posterior fixation/fusion in the treatment of distraction-flexion injury in the lower cervical spine.

This study compared the results of combined anterior and posterior fixation/fusion with those of anterior fixation/fusion alone through a retrospective review of 50 patients with a distraction flexion injury of the cervical spine. Group A (n=28) had unilateral facet joint subluxation or dislocation (Allen stage I or II) and anterior fixation/fusion alone. Group B (n=10) had bilateral dislocation (Allen stage III) and anterior fixation/fusion alone. Group C (n=5) had unilateral subluxation or dislocation and combined anterior and posterior fixation/fusion. Group D (n=7) had bilateral dislocation or total dislocation (Allen stage III or IV) and combined anterior and posterior fixation/fusion. The following parameters were analyzed: the change in the vertebral height and Cobb's angle, neurologic recovery, fusion time, fusion rate, surgery time, and the rate of complications. The mean fusion time was 3.75+/-2.10, 6.00+/-2.82, 3.60+/-1.34, and 3.85+/-2.26 months in groups A, B, C, and D, respectively. Group B had a significantly longer mean fusion time than groups A and D (Mann-Whitney U-test, P=0,012, P=0.014). There was a significant difference in the operation time between groups A and B and groups C and D. There were no significant differences in the changes in vertebral height and Cobb's angle, fusion rate, and neurologic recovery. The complications encountered were three cases of distal screw loosening in group A (n=2) and B (n=1), and three cases of delayed union in group A (n=2) and B (n=1). There were no complications in groups C and D. In those with a bilateral dislocation, the fusion time was increased when only anterior fixation/fusion had been performed but the clinical results, such as neurologic recovery and complications, were similar in the four groups. Overall, anterior fixation/fusion alone in a bilateral dislocation is recommended as an alternative method.