Study design: A cross-sectional comparison of vertebral morphology and lumbar lordosis (LL) in adolescents with and without spondylolysis.
Objective: To test the hypothesis that in addition to LL, vertebral cross-sectional area (CSA) is also associated with spondylolysis.
Summary of background data: Recent data indicate that the CSA of the vertebral body is a determinant of LL, which has been shown to be associated with spondylolysis.
Methods: Using magnetic resonance imaging, we compared the degree of LL from L1 to L5 and the CSA of the lumbar vertebrae in 35 adolescents (16 females and 19 males) with spondylolysis and 86 healthy controls (36 females and 50 males) of similar sex, age, height, and weight.
Results: There were no significant differences in age, height, weight, or vertebral height between subjects with and without spondylolysis, regardless of sex. In contrast, LL angle in spondylolysis patients was 57% and 51% greater in girls and boys with spondylolysis; 44.1 ± 10.4° versus 28.1 ± 9.8° and 34.8 ± 5.9° versus 23.0 ± 6.0° for girls and boys, respectively (both P's < 0.0001). Additionally, values for vertebral CSA were on average, 8% and 10% smaller in females and males with spondylolysis; 7.6 ± 0.8 cmversus 8.3 ± 1.1 cm and 8.4 ± 1.6 versus 9.3 ± 1.6 for girls and boys, respectively (both P's ≤ 0.039). Multiple linear and logistic regression analyses indicated that the CSA of the vertebral body was negatively associated with LL angle and an independent predictor of the presence of spondylolysis. This was true regardless of whether girls and boys were analyzed together or independently, and whether LL angle was measured from L1 to L5 or S1.
Conclusion: We provide evidence that patients with spondylolysis have increased LL and smaller vertebral CSA.
Level of evidence: 4.