Spinal cord stimulation for the control of spasticity in patients with chronic spinal cord injury: I. Clinical observations.

The effectiveness of spinal cord stimulation for control of spasticity was studied in 59 spinal cord injury patients. SCS was markedly or moderately effective in reducing spasticity in 63% of the patients. We found that control of spasticity by SCS was not correlated with the severity of spasticity, the type of spasticity (flexor or extensor), or the ability to ambulate. However, stimulation was more effective in patients with incomplete cervical lesions than in complete cervical lesions. Stimulation below the lesion was more effective than above. We conclude that SCS was effective when electrodes were properly positioned below the lesion over the posterior aspect of the spinal cord in patients with some residual spinal cord function. We hypothesize that SCS controls spasticity by modification of activity of spinal-brainstem-spinal loops and by suppression of segmental excitation through antidromic activation of propriospinal pathways.