The effect of lumbar multifidus cross-sectional areas on transforaminal epidural steroid injection: An observational clinical study.

Abstract

Multifidus has an important role in spinal stability, and multifidus degeneration causes long-term disability and low back pain. This study aimed to investigate the effect of multifidus cross-sectional area on transforaminal epidural steroid injections (TFESI). Patients with single-level disc herniation were included in the study. Total multifidus cross-sectional area (TM-CSA) and functional cross-sectional area (FM-CSA) were measured from axial T2 MRI of the patients, and FM-CSA/TM-CSA ratio was calculated for determination of muscle degeneration or fat infiltration. Numerical Rating Scale (NRS) scores at the pre-injection, 3rd week, and 3rd month visits were recorded. A decrease of 50% or more in the NRS score in the 3rd month was accepted as a treatment success (TS), and patients were divided into TS and treatment failure groups. A total of 120 patients were included in the study; 57 of the patients were female, and 63 of them were male. Of the patients included in the study, 68 had herniation at the L5-S1 disc level and 52 had herniation at the L4-L5 disc level. FM-CSA and FM-CSA/TM-CSA ratio were found to be significantly lower below the disc herniation level on the affected side (p<0.05). The affected side TM-CSA and FM-CSA were higher in the TS group and TM-CSA/FM-CSA ratios were equal in both groups. Multifidus CSA was found to be lower on the affected side. However, the effect of multifidus CSA on the success of TFESI has not been determined.