Skeletal Muscle Size, Intramuscular Fat and Spasticity after Incomplete Spinal Cord Injury (SCI)

Abstract

0253 Individuals with lower levels of SCI (LLOI), typically below T10, appear to have lower skeletal muscle mass in the legs than those with higher levels of SCI (HLOI). Also, intramuscular fat (IMF) has been correlated to plasma glucose levels following oral glucose challenge in SCI. PURPOSE: To compare skeletal muscle cross- sectional area (CSA), (IMF) and spasticity in incomplete SCI individuals with high (C5-C7) vs low (T12-L2) SCI and determine the relation, if any, between each of the first two variables and spasticity. METHODS: Thirteen individuals with acute, incomplete SCI were studied. The HLOI group was C5–C7 (n = 8, 26 ± 14 yrs, 82 ± 14 kg and 181 ± 6 cm) and the LLOI group was T12 – L2 (n = 5, 36 ± 14 yrs, 77 ± 14 kg and 180 ± 13 cm). T1 weighted magnetic resonance images were taken of both thighs 5 ± 1 weeks post SCI and spasticity was assessed with a modifled Ashworth scale (MAS). RESULTS: Skeletal muscle CSA was different between the left (112 ± 16 vs 78 ± 15 cm2) and right (103 ± 18 vs 80 ± 20 cm2) thighs, in the HLOI vs LLOI group (P = 0.04). IMF% of either thigh was about 3.4 ± 2.5 vs 7.4 ± 4%, in the HLOI vs LLOI group (P < 0.05). The HLOI group had six times more spasticity than the LLOI group (MAS = 2.4 vs 0.4, P = 0.01). The r2 for skeletal muscle size and spasticity was about 0.50 for either thigh (P < 0.006). CONCLUSION: The de-innervated skeletal muscles after LLOI show less spasticity and more atrophy than those after HLOI. Spasticity maintains skeletal muscle size and fat content after incomplete SCI. Supported by NIH grants HD37439-S1 (GAD), HD39676 (GAD) and the Foundation for Physical Therapy (CSB).