G.P.19.03 Working under stress: Premature aging of paravertebral muscles

Abstract

Intervertebral disc disease and instabilities of the vertebral column result in painful conditions with or without neurological deficits. After informed consent paravertebral muscle specimens were taken during surgery from 37 patients with disc protrusion and 26 patients with spondylolisthesis. Although myopathy related symptoms were absent, all biopsies showed alterations ranging from mild to severe. Neurogenic atrophy was present in almost half of the patients in both groups. Ragged red fibers were detected in 8 cases (21%) of the disc protrusion group and in 21 cases (80%) of the spondylolisthesis group. Intrasarcoplasmatic lipid and glycogen accumulation as indicators of an impaired mitochondrial function was frequently observed and appeared associated with mitochondrial accumulation. At the ultrastructural level the numerical increase of mitochondria was confirmed. They showed different configurational abnormalities as circular cristae and paracristalline inclusions. Another frequent finding was intrasarcoplasmatic lipofuscin pigment accumulation which was noticed even in young patients. It can be assumed that a premature aging of the muscle may result from inappropriate chronic stress due to pain and/or contractions. This may induce mitochondrial pathology similar to the classic mitochondriopathies as well as mitochondrial alterations found in senescence. In contrast to mtDNA mutations which are responsible for the above mentioned conditions, the pathological findings in this series are supposed to be secondary to local distress.