AP-translation in the proximal disc adjacent to lumbar spine fusion. A retrospective comparison of mono- and polysegmental fusion in 120 patients.

120 consecutive patients with painful spondylolisthesis underwent combined anterior and posterior fusion. Patients were divided retrospectively into two groups. In group I, 46 patients were treated with monosegmental fusion. In group II, 74 had polysegmental fusion. The mean follow-up time was 3 (2-7) years. Anterior posterior (AP)-translation in the first disc superior to fusion was measured according to Wiltse and Winter (1983). In group I, 3 and in group II, 10 patients developed an AP-translation of more then 3 mm in the disc adjacent to the fusion. AP-translation correlated with the number of fused segments and the follow-up time.