Clinical Results of Instrumentation Reduction and Posterolateral Fusion After Decompression of Symptomatic Lumbar Spondylolisthesis

From July 1990 to June 1993, 35 patients suffering lumbar spondylolisthesis (21 degenerative; 14 isthmic) were operated on and reviewed. They all had single-level involvement either L4-5 or L5-S1 and only this level was confined for operation. The operative procedures included decompression, posterolateral fusion and pedicle screw instrumentation for fixation and reduction of the vertebral slip. The age ranged from 42 to 65 years old, with an average of 55 years. There were 21 patients with grade 1 slip; 13 with grade II; and 1 with grade III. The follow-up periods ranged from 30 to 55 months with an average of 42 months. The clinical results were evaluated according to the improvement of low back pain, radicular pain, claudication and the incidence of fusion. Twenty-four patients (74%) were rated good to excellent and the fusion rate was 88%. However, there were 16 patients who still suffered from significant low back pain and who had reportd that such pain adversely affected the rating of clinical result. Loss of reduction were found in 16 patients, but there was no difference in clinical outcome between patients with or without reduction loss after the operation. The purpose of this paper is to report the clinical outcomes of the treatment of symptomatic spondylolisthesis with decompression, posterolateral fusion and instrumental reduction of the slip. The incidence of reduction loss and the prevalence of remaining low back pain are two important factors to consider in doing such reduction procedure. We inferred that slip reduction may not be a worthwile procedure in the treatment of adult spondylolisthesis if ordinary posterolateral fusion with short segment instrumentation is contemplated.