脊髄刺激を用いた重度脊髄損傷者における歩行機能再構築の試み

抄録

  Most patients with significant spinal cord damage have permanent symptoms and may be wheelchair-bound, depending on their residual motor function below the spinal cord lesion. Spinal cord damage, whether caused by injury or disease, is currently not repaired by any therapy. The sensory, motor, and autonomic functions of each segment depend crucially on connections with supraspinal sites for all conscious or voluntary actions. Damage to these connections leaves spinal segments caudal to the lesion site partially or totally isolated from the brain, resulting in debilitating consequences. Studies in humans have demonstrated, however, that the lumbosacral spinal circuitry retains an intrinsic capability to oscillate and generate coordinated rhythmic motor activity even when isolated from brain control. Although the anatomical architecture of locomotor central pattern generators remains poorly understood in mammals, the functional phenomenon of central pattern generation has been documented extensively. Techniques to stimulate spinal networks lend themselves as potent tools to facilitate locomotor recovery after severe spinal cord injury. Among several experimental strategies tested for activation of locomotor circuits in mammals after complete spinal cord transection, electrical stimulation has been investigated in human spinal cord injury. A recent clinical study demonstrated that some patients with complete paralysis were able to perform voluntarily controlled movements with epidural stimulation. In combination with epidural electrical stimulation of lumbosacral segments, activity-based rehabilitation can restore supraspinally mediated movements. Electrical neuromodulation therapies that activate spinal cord central pattern generators open up new avenues for treatment of spinal cord injury in human subjects.