Association Between Symptom Duration and Lesion Severity at Diagnosis in Symptomatic Adolescents with Lumbar Spondylolysis.

Abstract

Lumbar spondylolysis (LS) is a fatigue-related fracture commonly seen in adolescents. Progressive-stage lesions at diagnosis have been associated with poorer prognosis, including lower bone union rates and a longer time to return to sport. To clarify the association between symptom duration, lesion stage at diagnosis, and bilateral involvement in symptomatic adolescents with LS, and to determine the optimal symptom duration cutoff for predicting the presence of a progressive-stage lesion at diagnosis. Retrospective cross-sectional study. A total of 652 symptomatic adolescent patients with LS managed conservatively using a uniform treatment protocol at one hospital and four affiliated clinics between 2015 and 2023. Outcome measures included lesion stage based on computed tomography (CT) findings, lesion laterality (unilateral vs. bilateral). Symptom duration was defined as the interval from onset of low back pain to MRI-confirmed diagnosis of fresh LS. Patients were classified into three stages (very early, early, and progressive) based on CT findings. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal symptom duration cutoff for predicting the presence of a progressive-stage lesion at diagnosis. Median symptom duration was 1.1 weeks for the very early stage, 2.1 weeks for the early stage, and 5.7 weeks for the progressive stage. Patients with progressive-stage LS had significantly longer symptom duration than those with very early or early-stage lesions (both p < 0.001). Symptom duration was also significantly longer in patients with bilateral LS than in those with unilateral LS (3.9 vs. 2.0 weeks, p < 0.001). ROC analysis identified a symptom duration cutoff of 3.0 weeks for patients whose main lesion was classified as progressive (AUC = 0.775, 95% CI: 0.729-0.821). Longer symptom duration was associated with a more advanced lesion stage at diagnosis and bilateral involvement in adolescent LS. Early diagnostic interventions within 3-4 weeks of symptom onset may be critical for preventing stage progression and optimizing clinical outcomes.