Methods

Patients were asked to prospectively complete visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores on the day of their MRI scan. All patients with primary disc herniation were included. Exclusion criteria included recurrent disc herniation, cauda equina syndrome, or any other associated spinal pathology. T2 weighted MRI scans were reviewed on picture archiving and communications software. The T2 axial image showing the disc protrusion with the largest cross sectional area was used for measurements. The area of the disc and canal were measured at this level. The size of the disc was measured as a percentage of the cross-sectional area of the spinal canal on the chosen image. The VAS leg pain and ODI scores were each correlated with the size of the disc using the Pearson correlation coefficient (PCC). Intraobserver reliability for MRI measurement was assessed using the interclass correlation coefficient (ICC). We assessed if the position of the disc prolapse (central, lateral recess, or foraminal) altered the symptoms described by the patient. The VAS and ODI scores from central and lateral recess disc prolapses were compared.