Disc degeneration in patients with lumbar spondylolysis

The grade of intervertebral disc degeneration in 73 symptomatic patients with lumbar spondylolysis was evaluated with magnetic resonance imaging to assess the prevalence of disc degeneration. The results were compared with those of age- and sex-matched asymptomatic control populations and with patients with clinical back pain symptoms but without spondylolysis. The relationship between disc degeneration and age of patients, the duration and severity of clinical symptoms, and the grade of vertebral slip was evaluated. A five-point grading scale based on T2 signal intensity recommended by Gibson et al. was used to evaluate the degree of disc degeneration. The grade of disc degeneration below the spondylolytic defect in the patients was highly significantly related to the age of patients (p < 0.01) and was more severe than in the controls (p < 0.01), but there was no difference of disc degeneration above the defect between the patients and the controls (p > 0.05). Furthermore, the grade of disc degeneration below the spondylolytic defect in the patients was highly significantly correlated with the duration of clinical symptoms (p <0.01), although it was not associated with the severity of clinical symptoms or the grade of vertebral slip (p > 0.05). The results suggest that the degree of disc degeneration at the spondylolytic level is a more important determinant for choice of the fusion procedure than the age of the patients or the grade of vertebral slip, and that preoperative magnetic resonance examination is of great importance to evaluation of disc degeneration.