SURGICAL-TREATMENT OF SEVERE ISTHMIC SPONDYLOLISTHESIS IN ADOLESCENTS- REDUCTION OR FUSION INSITU

Twenty-two adolescent patients with severe (more than 50%) slip were s urgically treated. Eleven were reduced with Magerl/Dick transpedicular screw devices and fused posteriorly from L4 to S1, and 2 weeks later anteriorly L5-S1; the other 11 were fused in situ L4-S1 (6 patients) o r L5-S1 (5 patients) using a circumferential (6 patients), anterior (4 patients) or posterolateral (1 patient) technique without instrumenta tion. The two groups were comparable as to age at operation, age at fo llow-up, follow-up time, and preoperative radiologic measurement of th e slip, lumbosacral kyphosis, and clinical findings. The mean follow-u p times were 56.5 and 59.8 months, respectively. In the reduction grou p an improvement in the slip of 36.1 percentage points was achieved as compared with 7.7 percentage points in the in situ-fusion group. The sagittal rotation angle improved by 11 in the reduction group and wors ened by 2.8 in the in situ-fusion group. There were no differences bet ween the groups in the functional tests or clinical findings concernin g pain. Subjective assessment was good in both groups at follow-up; th at is, the pain had disappeared. Mean operation time and intraoperativ e blood loss were significantly higher in the reduction group. Reducti on procedures were also associated with a higher number of complicatio ns and reoperations. No neurologic complications, however, occurred in the reduction group. Based on this study, in situ fusions are to be p referred in adolescents with severe spondylolisthesis.