Making a case for programmable pumps over fixed rate pumps for the management of fluctuations in chronic pain and spasticity: a literature review.

This paper reviews data supporting the existence of individual, predictable, and unpredictable fluctuations in the severity of chronic pain and spasticity. It also evaluates what is known on the use of implantable programmable drug delivery systems for the management of predictable fluctuations in pain and spasticity. In addition to fixed rate infusion pumps, programmable drug delivery systems have been developed over the past 20 years for the management of predictable pain or spasticity fluctuations. The published literature on experimental and clinical studies of those topics is reviewed and evaluated. Programmable drug delivery systems can tailor dosing to a patient's individual pattern of symptoms, providing more medication during peak intensity of symptoms and less medication when symptoms are reduced. Fluctuations in either pain or spasticity are difficult to predict precisely, and therefore even programmable pumps cannot administer the appropriate amount of medication at any particular time. Ideally, the patient should be able to treat unpredictable fluctuations in symptoms, and a combination of patient controlled analgesia (PCA) with programmable drug delivery systems is currently in development. The future management of unpredictable fluctuations in the intensity of chronic pain and spasticity was subjected to critical evaluation. There seems to be a general agreement on the clinical importance of these phenomena, but stronger evidence is needed for a widespread change in the current management of most chronic pain patients.