Characteristics of fresh lumbar spondylolysis in elementary school students: a comparison between early elementary grade group and late elementary grade group.

Fifty-one elementary school students who were diagnosed with fresh lumbar spondylolysis using MRI between March 2015 and March 2022 were enrolled. Study 1 included 10 patients in the early grade group and 41 patients in the late grade group. The patients' characteristics at disease onset (sex, presence or absence of spina bifida occulta (SBO) in the affected vertebra, vertebral level, unilaterality or bilaterality of lesions, presence of a contralateral terminal stage, and disease stage) were compared between the two groups. Study 2 included 34 patients in whom the success or failure of bone union was confirmed. The bone union rates in both groups were compared, and factors that affected bone union in the entire study cohort were examined. In study 1, the proportion of patients with SBO, those with bilateral lesions, and those with advanced stages was significantly higher in the early grade group than in the late grade group. In study 2, the bone union rate was significantly lower in the early grade group than in the late grade group. Multivariate analysis revealed that in all the enrolled patients, advanced disease stage were factors that affected bone union. [ABSTRACT FROM AUTHOR]