Radiographic natural course of lumbar degenerative spondylolisthesis and its risk factors related to the progression and onset in a 15-year community-based cohort study: the Miyama study.

BACKGROUND

The natural history and risk factors for lumbar degenerative spondylolisthesis (DS) remain unclear. Because it is important for physicians to take these factors into account to ensure accurate decisions regarding surgical methods, this study aimed to elucidate the natural course and risk factors for the progression of DS.

METHODS

This is a prospective observation and case control study of 15-year follow-up in a rural mountainous cohort in Wakayama, Japan. In 1990 and 2005, a total of 200 participants (baseline age, range 40-75) were subjected to anteroposterior and lateral radiographs of the lumbar spine, which were acquired with patients in a standing position. The prevalence of DS (slip ≥3 mm) at baseline and the incidence of DS at 15-year follow-up were recorded. Risk factors at baseline for progression of L4 slip (≥3 mm) over the 15-year period were determined by multiple logistic regression analysis.

RESULTS

The overall prevalence of DS in 1990 was 10 % (20/200), and by spinal level was as follows: one case at L3, 14 cases at L4, and five at L5. In 2005, the overall prevalence of DS had risen to 22.5 % (45/200). Thus the incidence of de novo DS during the 15-year period was estimated at 14 % (25/180). Progression of the L4 slip (≥3 mm), regardless of baseline condition, was observed in 23 participants after 15 years. In multiple regression analysis, significant risk factors for L4 slip progression were identified as age less than 60 years, female sex, lumbar axis sacral distance, facet sagittalization, and existence of slip at baseline.

CONCLUSIONS

We successfully elucidated the risk factors for the progression of DS in a general population. Moreover, the results of this study identified preventive factors as well as risk factors for slip progression. This study provides useful information for physicians treating DS.