Spasticity may defend skeletal muscle size and composition after incomplete spinal cord injury.

Design:Cross-sectional.Objectives:(1) To determine the effects of the level of spinal cord injury (SCI) on skeletal muscle, intramuscular fat (IMF) cross-sectional areas (CSAs) and relative IMF; (2) to determine the relation, if any, of spasticity to each of these variables after incomplete SCI.Settings:In-patient study at the Shepherd Center, Atlanta, GA, USA.Methods:Thirteen individuals with incomplete SCI were classified according to their level of injury into a high level of injury group (HLI, C5–C7, n=8) and a low level of injury group (LLI, T12–L2, n=5). Spasticity was determined for thigh muscles using a modified Ashworth scale at 6 weeks post-injury. T1-weighted magnetic resonance (MR) images were taken 6 weeks post-injury to measure thigh skeletal muscle and IMF CSAs.Results:Spasticity was significantly evident in the HLI group compared to the LLI group (P=0.023). Six weeks post-injury, muscle CSA was 103±18 cm2 in the HLI group and 80±20 cm2 in the LLI group (P=0.042). Relative IMF was 3.6±2.0% in HLI and 7.5±4.0% in LLI (P=0.021). Additionally, spasticity accounted for 54% of the variability in muscle CSA for all subjects (r 2=0.54, P=0.006).Conclusions:Spasticity may be an important factor in defending skeletal muscle size and indirectly preventing IMF accumulation early after incomplete SCI.Spinal Cord (2008) 46, 96–102; doi:10.1038/sj.sc.3102087; published online 17 July 2007 [ABSTRACT FROM AUTHOR]