Background context: Sarcopenia, an overall reduction in skeletal muscle mass, was shown to correlate with pain and disabil i ty in pat ients with degenerat ive lumbar scol iosis (DLS). Previous s tudies report that paraspinal muscle morphology correlates with radiographic paramete rs of DLS. However , no s tudy investigated the effects of overal l core muscle morphology, including hip and abdomen muscles , on pain and disabi l i ty in these patients . Purpose: The pr imary goal of this s tudy was to investigate the correlat ion between core muscle morphology with pain and disabil i ty in DLS pat ients . The secondary outcome was the correlat ion between core muscle morphology and radiographic parameters . Design: Cross-sect ional s tudy Pat ient sample: Seventy -six women and f i fteen men (mean age 70.2 ± 8.4 years) with de novo degenerative lumbar or thoracolumbar scol iosis , referred to a s ingle ter t iary hospi tal , were ret rospect ively analyzed. Pat ients with complete cl inical quest ionnaires , whole spine radiographs and an avai lable t runcal computed tomography (CT) scan were included. Outcome measures: Pain was assessed uti l iz ing visual analog score for back (back VAS) and leg pain (leg VAS), whi le disabi l i ty was assessed using the Oswestry Disabi l i ty Index (ODI) and Short Form -36 (SF-36) scores . Coronal ver t ical a l ignment (CVA) and sagi t tal vert ical a l ignment (SVA) as wel l as Cobb angle (CA), lumbar lordosis (LL) and spinopelvic parameters , such as pelvic incidence (PI) , pelvic t i l t (PT) and pelvic obl iqui ty (PO) were measured. Methods: Relat ive cross -sect ional areas (rCSA) and intramuscular fatty inf i l t rat ion rat io (FI) were calculated for hip, abdomen, and paraspinal muscles . Univar iable and multivar iable l inear regression analyses were conducted for pain and disabi l i ty scores . Pearson ’s correlat ion analysis between muscle morphology and radiographic parameters was done. Results: In both univar iable and mult ivariable analysis , gluteus maximus FI was shown to affect back VAS (p=0.022; p=0.045, respectively) and SF-36 PCS (p=0.005; p=0.023, respect ively) , whi le gluteus medius FI was shown to affect SF -36 PCS (p=0.002; p=0.011, respectively) . Abdomen and paraspinal muscles did not show any s tat is t ical s ignif icance with pain and disabil i ty scores . Coronal ver t ical a l ignment was only associated with gluteus maximus FI (p=0.000) and gluteus medius FI (p=0.001) , whereas sagit ta l v er t ical al ignment was associated with gluteus maximus FI (p=0.022) , gluteus medius FI (p=0.022) , mult i f idus rCSA (p=0.000) and erector spinae rCSA (p=0.030) . Conclusions: Fat ty inf i l trat ion of hip muscles , gluteus maximus and gluteus medius, affect back pain and disabi l i ty in DLS pat ients , and correlate with global spinal malalignment . Paraspinal muscles does not s ignificantly affect pain and disabil i ty between DLS pat ient s , but correlates with lumbar deformity, multiple spinopelvic parameters and sagi t ta l spinal a l ignment . Abdomen muscles were not s ignif icant ly associated with neither radiographic nor cl inical parameters in DLS. Key word: Lumbar Vertebrae; Scoliosis; Muscles; Tomography, X -Ray Computed; Pain Measurement; Disabil i ty Evaluat ion; Cross -Sect ional Studies
