Factors Influencing to Clinical Outcomes of the Surgically Treated Degenerative Lumbar Spondylolisthesis / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: To examine the factors considered in the selection of therapeutic methods, and the methods for accessing postoperative clinical outcomes, in degenerative lumbar spondylolisthesis. OBJECTIVES: In this retrospective study, patients who had taken only posterolateral fusion, and with a posterior lumbar interbody fusion, were evaluated. The analyses of the pre- and post-operative factors associated with the clinical outcomes of the surgery for degenerative lumbar spondylolisthesis were also performed. MATERIALS AND METHOD: Of the patients who had received the surgery for degenerative lumbar spondylolisthesis, between January 1995 and December 2000, there were 59 for whom follow-up observations were possible, and these were selected for the present study. The patients were comprised of 19 males and 40 females, with ages ranging from 42 to 74 years (58.4+/-8.4 years old). Of the 59 patients, 39, and 20, received a posterolateral fusion, or both a posterolateral fusion and a posterior lumbar interbody fusion, respectively. In the present study, the pre-operative factors considered were the surgical method, sex, age, L1 axis S1 distance (LASD), lordosis angle and the degree and duration of spondylolisthesis, with the degree of fusion, the lordosis angle of the fused body, the lordosis angle at the final follow-up and the lordosis angle of the fused body at the final follow-up, used as the post-operative factors. Each factor was statistically tested to see if it had a significant correlation with clinical outcomes (Recovery rate by Hirabayashi's method). A value of P < 0.05 was considered as being statistically significant. RESULT: The posterolateral fusion group showed a significantly lower recovery rate with an LSAD over 35 mm, a degree of spondylolisthesis over 10 mm and a pre-operative lordosis angle under 20 degrees, indicating that an additional posterior lumbar interbody fusion would provide a good clinical outcome. At the final follow-up, both groups showed significantly lower recovery rates with a lumbar lordosis angle under 20 degrees, and the posterolateral fusion group showed significantly lower recovery rates when the post-operative lordosis angle of the fused segment was under 18 degrees, and with a lordosis angle of the fused segment was under 18 degrees at the final follow-up. These post-operative factors showed significant correlations with the clinical outcomes. CONCLUSIONS: It is considered that an additional posterior lumbar interbody fusion is indicated in patients with a LSAD over 35 mm, an anterior slippage over 10 mm and a lumbar lordosis angle over 20 degrees. It is also considered that the lordosis angles of the fused segment, and the post-operative lumbar lordosis, are important factors that require peri-operative correction and maintenance.