Introduction:
Lumbar spondylolysis during growth is a fatigue fracture between the articular processes of the lumbar spine, due to the concentration of high stress during extension and rotation. The fusion rate of lumbar spondylolysis during growth has been previously reported. However, there is no consensus, possibly due to variations such as age, affected side, disease stage, and type of treatment brace. This study aimed to determine whether unilateral lumbar spondylolysis in adolescents can be effectively treated using semi-rigid braces. The fusion rate and time to fusion of lumbar spondylolysis with a semi-rigid brace by stage (morphology) of the disease were examined.
Method:
Patients with unilateral lumbar spondylolysis, who visited our clinic from 2015 to 2019, treated with a semi-rigid brace, and followed to treatment completion were retrospectively reviewed. The primary diagnostic criterion was the detection of high signal areas in the pedicle on magnetic resonance imaging (MRI). We also evaluated the morphological stage of the disease by computed tomography (CT). Based on CT findings, patients were categorized into ultra-early (no findings), early (cracks of the lamina on lateral view), progressive (no continuity of the lamina), and terminal (pseudarthrosis) stages. Bone fusion was determined using a CT scan following the resolution of extension back pain in patients.
Results:
The study included 127 patients (106 males and 21 females; mean age =14.8 ± 1.4 years). encompassing 134 sites. Of these, 7 were in the ultra-early stage, 121 in the early stage, 5 in the progressive stage, and 1 in the terminal stage. In 12 (9%), 41 (30.6%), and 81 (60.4%) of cases, the level of onset was at L3, L4, L5, respectively. There was a left-side predominance (right-sided in 53 [39.6%] vs. left-sided in 81 [60.4%]). Treatment was successful in 115 cases (90.6%). Treatment was considered to have failed in the remaining 12 (9.4%) patients showing persistent high signal areas in the post-treatment MRI. The fusion rate by stage is as follows: 100% for ultra-early (7/7), 94.2% for early (114/121), 40% for progressive (2/5), and 0% for terminal (0/1), indicating a slight decrease as the stage advanced. The average treatment duration was 9.6 weeks for the ultra-early stage, 14.4-21.7 weeks for the early stage, and 34.2 weeks for the progressive stage, indicating that a prolonged healing time is required as the condition progresses.
Discussion:
Treatment of unilateral lumbar spondylolysis in adolescents using a semi-rigid brace yielded an overall high fusion rate. Treatment effectiveness in the ultra-early and early stages was marked. However, as the disease stage progressed, the fusion rate declined, suggesting a need to reconsider treatment options based on disease staging. A semi-rigid brace appears to be particularly effective for early lumbar spondylolysis. For patients in advanced stages or those unlikely to benefit, alternative treatment strategies are warranted.