The grading model for the assessment of the total amount of epidural fibrosis in postoperative lumbar spine

Purpose To present a new model derived from Ross’s model for the assessment of the total amount of epidural fibrosis and to present inter- and intravariability study. Methods Two readers blinded to each other and blinded to their first and second reading retrospectively evaluated the magnetic resonance examinations in 32 postoperative spine surgery patients using this model. Results Paired and unpaired two-sided t tests showed no significant difference between the first and second reading, and interclass correlation coefficient revealed good interobserver reliability. Conclusion The proposed model enables estimation of the amount of epidural fibrosis in postoperative lumbar spine and does not require any additional software or hardware. It is designed for multi-centered clinical studies where it is necessary to compare the values of epidural fibrosis between the tested and control group. The use of the proposed model is fast and practical and helps to avoid complications arising from image format, calibration and software, which are often encountered in multi-centered studies.