Paraspinal muscle quality in chronic low back pain: a systematic review and meta-analysis of muscle atrophy and fat infiltration. - Kalli I; Niglas M; Naeini MK; Freidin M; Thomas L; Menni C; Williams F (European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2026)