Selection of Patients for Implantable Intraspinal Narcotic Delivery Systems

The use of intraspinal narcotics represents a major advance in the management of pain of malignant origin. For patients whose pain is uncontrolled by narcotic analgesics and adjunctive drugs, a trial of intraspinal narcotics is warranted. If the patient perceives adequate pain relief, an implantable intraspinal narcotic delivery system (INDS) may be indicated. The use of epidural narcotics to treat cancer pain was first described by Behar et al. in 1979 (1). More recently, a variety of implantable INDSs have been described (Table 1) for long-term intraspinal narotic administration (2-8). Most authors agree on the need for a preimplantation trial of intraspinal narcotics, but no mention is made of any patient selection process. We wish to describe the selection process that we have used prior to implanting one particular INDS, type I11 INDS, in 35 patients, and to review the factors that must be evaluated when considering a patient for an INDS. As with any pain management procedure, appropriate patient selection is crucial to ensure a successful outcome. The first factor to consider when selecting a patient for implantation of an INDS is whether intraspinal narcotics adequately relieve the patient’s pain. Not all pain is relieved by intraspinal narcotic (9-11). For this reason, an implantable INDS should never be implanted without first verifying the ability of intraspinal narcotics to relieve the patient’s pain on at least two occasions. Failure to do so could subject the patient to implantation of a delivery system that fails to achieve the desired results-namely pain relief.