Low back pain is frequently seen in the adolescent age group, with a prevalence approaching that of the adult age group. The most common type is non-specific, self-limiting low back pain. LDH is rare in children and adolescents and generally presents with low back pain, with or without radiculopathy. The condition is usually unilateral (especially L4-5 or L5-S1). LDH is also mostly central type. Although there are many studies that have investigated the relationship between paraspinal muscle volumes and LBP and/or LDH in the adult age group, there are very few studies in adolescents. The principal aim of this study was to compare MF, ES, and PM volumes in adolescents with LBP with and without LDH using magnetic resonance imaging (MRI) and to determine whether these two conditions cause paraspinal muscle volume loss.

The medical records of 229 patients who underwent MRI due to low back pain persisting for a minimum of twelve weeks between January 2018 and January 2020 were evaluated retrospectively. Twenty-four patients were excluded due to the presence of spondylolysis-listhesis, spinal alignment disorders including scoliosis and kyphosis, inflammatory diseases, or histories of spinal surgery and multilevel disc hernia. Two hundred five patients were finally enrolled. Age, gender, weight, and height were recorded, and BMI was calculated as weight/(height)². Participants were divided into two groups - with LDH (Group A) and without LDH (Group B). Right- and left-side PS, MF, and ES muscle volumes at intervertebral disc levels L4-L5 and L5-S1 were measured on Axial T2-weighted fast spin-echo sequences. All cross-sectional images at both levels (L4-5 and L5-S1) were generated by means of multiplanar reformat images. The muscles were identified by means of manual contouring at both disc levels. The fat components were then eliminated by application of the threshold technique, based on visual differences in pixel signal intensities. Volume measurement from cross-sectional images was based on the use of an automatic volume calculation tool.

Inclusion Criteria:

• Aged 10-18
• LBP persisting for a minimum of twelve weeks

Exclusion Criteria:

• spondylolysis-listhesis
• spinal alignment disorders including scoliosis and kyphosis
• inflammatory diseases
• histories of spinal surgery
• multilevel disc hernia

The patients (aged 10-17) with low back pain persisting for a minimum of twelve weeks