Myoglobin and enzyme adaptations in erector spinae muscles in thoracal scoliosis

Bilateral biopsies from the erector spinae muscles were taken during surgery from 10 females and two males (mean age 14, range 13-17 years) with thoracal scoliosis for 6 years (range 2-11 years). The biopsies were analysed for myoglobin (MYO), citrate synthase (CS) and creatine kinase MB (CK-MB). The severity of scioliosis was estimated by Cobb's angle, the greater the angle the more severe the disease. The convex/concave side ratio (CVX/CCV) was for CS 1.3 +/- 0.4 (P less than 0.01), CK 0.9 +/- 0.1 (P less than 0.05), CK-MB 1.6 +/- 0.4 (P less than 0.01) and for MYO 1.1 +/- 0.2 (P greater than 0.05). No significant correlations were found between the CVX/CCV for CS, CK or CK-MB on the one hand and the Cobb's angle on the other. The CVX/CCV for MYO was, however, directly related to the angle (r = 0.80, P less than 0.01). For the lower range of angles (less than or equal to 59 degrees) the CVX/CCV for MYO was below unity (0.88, P greater than 0.05) and for the larger angles (greater than 59 degrees) above unity (1.23, P less than 0.05). In conclusion, a dissociation in the adaptive response of m. erector spinae in scoliosis between mitochondrial enzyme and myoglobin content was demonstrated.