Spasticity is characterized by increased resistance to passive movement, hyperactive reflexes, and simultaneous activation of antagonistic muscle groups. Characteristic postures include scissoring of legs or hyperflexion of the thighs. These postures may be painful, or may disrupt the patient's ability to sit in a wheelchair, lay in bed, drive modified vehicles, or sleep. Results from lesions in upper motor neuron pathway, causing absence of inhibitory influence on alpha-motor neurons as well as on gamma motor neurons.
Treatment depends upon the extent of useful function present.
Myelotomy Selective dorsal rhizotomy - uses intraoperative EMG and electrophysiological stimulation to eliminate sensory rootlets involved in spasticity.