Minimum 10-year follow-up study of anterior lumbar interbody fusion for isthmic spondylolisthesis

The aims of the current study were to evaluate the long-term clinical and r adiologic results of anterior lumbar interbody fusion (ALIF) for isthmic sp ondylolisthesis. Between 1981 and 1988, a total of 35 patients underwent AL IF for isthmic spondylolisthesis. Of these, 23 patients were followed clini cally and radiographically for more than 10 years (average, 13.3 years). Th e Japanese Orthopaedic Association low-back pain score was used to evaluate the outcome of subjective symptoms and clinical signs. The preoperative an d postoperative percentage of slip, preoperative and postoperative interver tebral disk height, interbody graft union, and pars defect union were evalu ated by serial radiographs. The adjacent disk degeneration was also evaluat ed by radiographs and magnetic resonance imaging. Although the low-back pai n score worsened after 5 years, ALIF provides satisfactory overall long-ter m clinical results. The preoperative percentage of slip and the disk height were corrected after surgery, but at the time of interbody graft union, sl ip and disk height recurred as a result of grafted bone collapse. The rate of union in the grafted area was 83%. In the nonunion cases, the scores gra dually deteriorated with time, but the overall results were not different f rom those of union cases. Radiographs showed adjacent disk degeneration in 52% of cases in the upper adjacent level and in 70% of cases in the lower a djacent level, but these changes were not correlated with clinical outcomes .