Pediatric lumbar spine MRI: structural imaging findings and anatomical variants associated with disc herniation.

Abstract

This study aimed to evaluate the clinical indications, imaging findings, and structural factors identified on pediatric lumbar MRI, with a specific focus on non-traumatic low back pain and lumbar disc herniation (LDH). A retrospective review was conducted of 1,253 lumbar MRI examinations performed in pediatric patients aged 0-18 years between November 2022 and March 2024. Clinical indications were documented for all patients. Imaging findings were systematically analyzed in children presenting with non-traumatic low back pain. In patients diagnosed with LDH, the presence of lumbosacral transitional vertebrae (LSTV), spondylolysis, and spondylolisthesis was reassessed. LSTVs were categorized using the Castellvi classification. Low back pain was the most common indication for MRI (n=650, 51.9%). Among these children, 62.3% had normal examinations. Disc protrusion (15.1%), degenerative disc or endplate changes (8.9%), spondylolysis (5.5%), and spondylolisthesis (2.8%) were the most frequent abnormalities. LDH predominantly occurred at the L5-S1 level. LSTVs were identified in 52 patients (8%) with LDH, and higher-grade Castellvi types were significantly associated with LDH (p<0.001). Lumbarization of S1 was observed in 10 LDH patients, typically showing squaring of S1 and prominence of the S1-2 disc space. Although most pediatric lumbar MRI examinations performed for low back pain are normal, MRI remains essential for identifying clinically relevant structural abnormalities. LDH is more common in older adolescents and is associated with anatomical variants such as LSTV and lumbarization. Recognition of these variations, combined with adherence to evidence-based imaging recommendations, is crucial for accurate diagnosis and appropriate clinical management in children with low back pain.