The objectives of this study are to evaluate the effectiveness, long-term safety, tolerability, satisfaction with treatment, and health-related quality of life (HRQoL) associated with Intrathecal PRIALT use for severe chronic pain of varying etiologies.

Inclusion Criteria:

• Patient is at least 18 years of age at the time of study entry.
• Patient who has severe chronic pain, whom IT therapy is warranted, and who is intolerant of, or refractory to other treatments, such as systemic analgesics, adjunctive therapies, and/or IT morphine.
• Patient is planned to be initiated on IT PRIALT as the sole agent in the pump at a participated site.
• Patient has not received PRIALT treatment administered continuously via Medtronic SynchroMed® II pump within the past 30 days.
• Patient has a life expectancy >6 months as determined by the physician.
• Patient is able to read, understand, and voluntarily sign the IRB-approved informed consent document prior to the performance of any study-specific procedures.
• Patient is able to understand and complete required assessments.

Exclusion Criteria:

• Patient has a known hypersensitivity to PRIALT or any of its formulation components.
• Patient has a pre-existing history of psychosis.
• Patient has infection at the microinjection site, uncontrolled bleeding diathesis, or known spinal canal obstruction that impairs circulation of cerebrospinal fluid.
• Patient is being initiated with PRIALT in conjunction with other IT agents.
• Patients with any other concomitant treatment or medical condition that, in the opinion of the clinician, would render IT administration hazardous.

Up to 140 patients will be enrolled at approximatley 50 sites in the United States.