The evaluation of lumbosacral dysplasia in young patients with lumbosacral spondylolisthesis: comparison with controls and relationship with the severity of slip

Abstract

Introduction: Comparison of lumbosacral dysplasia between normal individuals and patients with low and high grade spondylolisthesis has not been done previously. The objective of this study is to evaluate the relationship between lumbosacral dysplasia and severity of slip in young patients with lumbosacral spondylolisthesis.

Methods: Postero-anterior and lateral radiographs of 120 normal individuals and 131 patients with developmental spondylolisthesis (91 low and 40 high grades) were reviewed. Quantitative evaluation of lumbosacral dysplasia was done using 6 criteria involving the degree of laminar dysplasia, degree of facet dysplasia, size of L5 transverse processes, L5/S1 disc height, type of sacral doming and L5 lumbar index. Subjects were categorized as having no/low, moderate or severe dysplasia based on the total dysplasia score. Comparisons in total dysplasia score between normal, low grade and high grade groups were performed and the correlation between degree of dysplasia and percentage of slip was assessed.

Results: Most normal individuals (88.3%) had no/low dysplasia; most patients with low grade spondylolisthesis (61.5%) had moderate dysplasia, while most patients with high grade spondylolisthesis (72.5%) had severe dysplasia. There was a significant difference in dysplasia between normal individuals and patients with spondylolisthesis. Dysplasia also varied significantly between low and high grade spondylolisthesis. There was a strong positive correlation (r = 0.63) between severity of dysplasia and percentage of slip.

Conclusion: There is a significant relationship between the severity of spondylolisthesis and lumbosacral dysplasia, with mainly no/low dysplasia observed in controls and increasing total dysplasia scores in higher grades of spondylolisthesis. In addition, a variable degree of dysplasia was found within groups with low or high grade spondylolisthesis, suggesting that different subgroups of patients exist with regard to dysplasia. Thus the degree of dysplasia varies in spondylolisthesis and it is possible that different grades of dysplasia could relate to different prognoses or outcomes with treatment.

Fig. 1

Criteria for assessment of lumbosacral dysplasia

Fig. 2

Radiographs of a control subject with no/low dysplasia (total dysplasia score of 0). He has normal laminae, facets, L5 transverse processes, L5–S1 disc height and upper sacral endplate. The lumbar index is 0.94

Fig. 3

Radiographs of a patient with low-grade spondylolisthesis and moderate dysplasia (total dysplasia score of 5). The patient has spinal bifida occulta, normal L5 transverse processes, hypoplastic facets, a lumbar index of 0.60, normal L5/S1 disc height and moderate anterior doming of sacrum

Fig. 4

Radiographs of a patient with high-grade spondylolisthesis and severe dysplasia (total dysplasia score of 11). The patient has absent laminae, almost absent L5 transverse processes, aplastic facets, a lumbar index of 0.57, L5/S1 disc height between 25 and 75% of L4/L5 disc height, and a high centered doming of S1

Fig. 5

Radiographs of a patient with high-grade spondylolisthesis and no/low dysplasia (total dysplasia score of 4). The patient has spina bifida occulta, normal transverse processes of L5, normal L5/S1 disc height, lumbar index of 0.76, normal facets, and moderate anterior sacral doming