Transitioning to a Valve -Gated Intrathecal Drug Delivery System (IDDS)

This open-label, non-randomized, single-blind, multi-center study is designed to evaluate effects of a planned 20% dose reduction when converting to valve-gated from a peristaltic pump. Study participants will be blinded (single blind) to the dose reduction aspect of this trial and must remain blinded to this dose reduction information throughout the trial in an attempt to provide an unbiased assessment of the pain encountered by the patient with their pain pump medications used. This study will compare the historical pain medication dose and pain scores using the peristaltic pump at baseline as well as from the last pump refill visit prior to explant to the prospective pain medication dose and pain scores using the valve-gated pump and collected at refill visits 1, 2 and 3 after valve-gated pump implant (but not exceed 12 months).