ABSTRACT

The aim of this retrospective study was to determine the effect of the number of fusion levels on the clinical results of adult isthmic spondylolisthesis patients who had undergone posterior instrumentation and fusion.

This retrospective study comprised 37 (20 male, 17 female) patients. Radiological evaluation was made by anteroposterior, lateral, oblique and lateral flexion-extension x-rays. The mean age of the patients was 36.4± 9.2 years and the mean follow-up period was 34.3 months. Three segment fusion was applied to 22 patients and two segment fusion was applied to 15 patients.

In the single-level group screw loosening occurred in 3 patients and screw breakage in 1 due to the pseudoarthrosis. This study has demonstrated that two-level posterior instrumentation and fusion with local bone grafts and demineralized bone matrix have significantly better clinical and radiological results than single-level surgery. To avoid potential complications of posterolateral interbody fusion, two-level posterolateral fusion can be an alternative treatment option.