Intra-Spinal Stimulation Leads to Activation of Motor Modules and Restoration of Monitored Movements in Spinally-Injured Rabbits

Abstract

Electrical stimulation of functional units (modules) in an injured spinal cord is the primary strategy to restore neuromuscular movements. The current study aims to evaluate the efficacy of the motor module activation in male Dutch rabbit models with injured spinal cord to mimic monitored movements using intra-spinal stimulation. Leg-angle movements were monitored in three rabbits before and after spinal injury using a digital camera with 40 frames/sec. To obtain the leg-movement model before injury, three movements were considered as monitored movements. Then the rabbits were anesthetized and a T7-L4 laminectomy was performed. After spinal injury, the leg-angle movement was mimicked in the anesthetized rabbits with a custom–made stimulator by scanning the spinal cord to locate the leg-angle movements related motor modules. Subsequently, three stimulating electrodes were fixed on the located modules for restoring monitored movements. Finally, the leg-angle movements were analyzed using paired t-student test. Root mean square tracking error was calculated between normal and mimicked leg-angle movements. Based on our data, a combination intra-spinal stimulation of three motor modules, led to no significant difference in hip, knee and ankle angles as compared to those recorded before induction of injury. The RMS errors were 6.26±1.17o, 6.07±1.20o and 6.70±0.92o for the hip, knee and ankle respectively. Overall RMS for our data was 6.12±1.27o. The detection of motor modules in spinal cord and their stimulation is able to restore the monitored movements with a good tracking performance; thus, it can be used to recover motion patterns in spinally-injured rabbits.