Progression of Preoperative Degeneration of the Adjacent Segmentafter Instrumented Lumbar Arthrodesis / 대한정형외과학회잡지

ABSTRACT

PURPOSE: Preoperative degeneration has not been clearly defined as a risk factor of adjacent segment disease (ASD). The aim of this study was to analyze the progression of preoperative degeneration at the adjacent segment after instrumented lumbar fusion. MATERIALS AND METHODS: Forty-eight patients (mean age 63.9, range 39-77) who underwent posterolateral fusion for a degenerative lumbar spine were reviewed. All the patients showed preoperative degenerative changes at the adjacent segment. The preoperative degeneration included disc degeneration (n=42), degenerative lumbar scoliosis (n=7), posterior translation (n=7), lateral translation (n=9), and spondylolisthesis (n=1). The patients were divided into the following three groups according to the progression of degeneration Group I, No progression; Group II, asymptomatic radiographic progression; and Group III, symptomatic progression. RESULTS: There were 22, 15, and 11 patients in Groups I, II and III, respectively. The incidence of symptomatic progression of degeneration was 22.9%. Of the 42 patients showing disc degeneration, 9 patients (21.4%) developed symptomatic progression. On the other hand, 3 out of 7 (42.9%) patients with posterior translation and 5 out of 7 (71.4%) patients with degenerative scoliosis developed symptomatic progression. The age and number of fused segments were not predisposing factors to progression. CONCLUSION: The incidence of symptomatic adjacent segment disease in patients with preoperative degeneration was 22.9%. Preoperative coronal malalignment and posterior translation might be risk factors for adjacent segment disease. Correct selection of the fusion level is important for reducing the incidence of adjacent segment disease.