Prevention of deep tissue injury through muscle contractions induced by intermittent electrical stimulation after spinal cord injury in pigs

Solis et al, 2013 [pre-clinical; pigs] aimed to assess the long-term effectiveness of IES in pigs that had received a partial spinal cord injury that paralyzed one hindlimb. The pigs recovered for 2 weeks post-surgery, and subsequently, their paralyzed limbs were loaded to 25% of their body weights 4 h/day for 4 consecutive days each week for 1 month. One group of pigs received IES during the loading, whereas another group did not. Stimulation was delivered through a pair of electrodes placed on the skin (5 × 10 cm; Pure Care, Sherwood Park, AB, Canada) and a hand-held stimulator (BioStim NMS+ Stimulator; Biomedical Life Systems). The active electrode was placed over the motor point of the superficial gluteus muscle, whereas the return electrode was placed over the middle gluteus muscle. Stimulation consisted of trains of biphasic, charge-balanced, square pulses. Pulse width was 250 μs and pulse frequency 35 Hz. Pulse amplitude was adjusted individually for each pig to generate a visible fused contraction in the targeted muscle. The IES cycle consisted of 10 s of stimulation (“on” period) followed by a 10-min period of no stimulation (“off” period). The authors found that in the group that did not receive IES, MRI assessments revealed signs of tissue damage in 48% of the volume of the loaded muscle. In the group that did receive IES, only 8% of the loaded muscle volume showed signs of tissue damage. Similar findings were found through postmortem histology. Which demonstrated that IES may be an effective technique for preventing the formation of DTI in loaded muscles after spinal cord injury.