The paravertebral muscle and psoas for the maintenance of global spinal alignment in patient with degenerative lumbar scoliosis

Abstract Background context Various factors are reported to affect the spinal alignment in degenerative lumbar scoliosis (DLS). Although trunk muscles also appear to affect spinal alignment, the role of the trunk muscles is not yet clear. Purpose The aim was to elucidate the role of the multifidus (MF) and psoas (PS) in maintaining global spinal alignment in patients with DLS. Study design This was a multicenter retrospective matched cohort study. Patient sample Surgically treated 60 paired DLS and lumbar spinal stenosis (LSS) female (120 patients), matched for age and body mass index (BMI; DLS age 68.0±6.8 vs. LSS 67.1±8.9 years; BMI 21.6±3.3 vs. 23.2±3.8 kg/m2 ), were included and were followed for at least 2 years. Outcome measures Spinal alignment, muscle area, and volume were measured from radiographs, magnetic resonance images (MRIs), and whole-body dual-energy X-ray absorptiometry (DXA) scans. Muscle strength was measured by grip power and peak expiratory flow (PEF). Methods As a surrogate of muscle area, we obtained the cross-sectional area (CSA) at the L5–S level from preoperative MRIs. Results The MF and PS CSAs were significantly smaller in the DLS group than in the LSS group (MF 477.7±192.5 vs. 779.8±248.6 mm2 , p