Continuous Intrathecal Baclofen Infusion for Chronic Spasticity

Inclusion Criteria: The overall goal of this study is to choose patients most likely to experience therapeutic success while reducing the likelihood of risks, complications and adverse events. Patients meeting all of the following criteria will be eligible for enrollment in the study: 1. Patient with a history of severe chronic spastic hypertonia in the lower extremities lasting at least 6 months who: * fail to respond to maximum recommended doses of antispasmodic medications including baclofen, or * those who experience intolerable CNS side effects at effective oral doses 2. Patient is \>21 years of age 3. Patient, or legally authorized representative (LAR), has provided written informed consent to participate in the study 4. Investigator considers the patient willing and able to fulfill all study requirements 5. Investigator has documented attempts to eliminate factors that can contribute to an increase in spasticity (e.g. infection) 6. Patient has had a successful trial of Lioresal® for the management of the target spasticity. Exclusion Criteria: Patients meeting any of the following criteria are to be excluded from the study: 1. Patient has MRI of the spine documenting structural abnormality preventing adequate CSF flow. (If the patient has a medical condition that contraindicates screening MRI, the investigator should proceed with the closest appropriate study i.e. CT scan, X-ray, to rule out any spinal abnormalities that would prevent intrathecal drug administration.) 2. Patient's anatomy is not large enough to accommodate the pump's size and weight. 3. Patient has a systemic infection. 4. Patient has renal insufficiency as evidenced by a baseline serum creatinine of \>2.0 mg/dl. 5. Patient has a history of a bleeding disorder. 6. Patient has a history of blood clots such as deep vein thrombosis (DVT) or pulmonary embolism (PE) within 1 year of enrollment. 7. Patient is pregnant or breast-feeding, or is of child-bearing potential and not employing effective birth control. 8. Patient has known allergies or sensitivities to pump system materials (e.g., silicone rubber, titanium, polyphenylsulfone, acetal resin, polyvinylidene fluoride, tungsten). 9. Patient has known allergies to Lioresal® (baclofen), or would be contraindicated for Lioresal® based on the drug labeling. 10. Patient has other implantable electronic cardiac devices (i.e. pacemaker, defibrillator, CRT system) 11. Patient has an occupation where he/she would be exposed to high current industrial equipment, powerful magnets or transmitting towers, such as, electricians, electrical engineers or MRI technicians. 12. Patient is participating in another clinical trial.