Spasticity is caused by an increase in muscular tone resulting in stiffness of the muscles and a restriction of movement. Patients may develop pain, permanent contraction of the muscles and alterations in posture. Often, quality of life is impacted substantially due to these symptoms. Spasticity usually develops in patients with spinal cord injury, cerebral palsy, multiple sclerosis or stroke. Treatment may involve a regimen of medication, exercise and physical therapy, and may be supplemented by botulinum toxin injection or surgery. Surgical treatments may include relaxation of muscles by release of tendons, implantation of a baclofen pump or cutting nerve fibers (selective dorsal rhizotomy)