Efficacy and technical complications of long-term continuous intraspinal infusions of opioid and/or bupivacaine in refractory nonmalignant pain : A comparison between the epidural and the intrathecal approach with externalized or implanted catheters and infusion pumps

Objective: To compare efficacies, failure rates, and technical complication rates of intraspinal treatments in patients with refractory nonmalignant pain conditions in relation to the approach (epidural/intrathecal), the drug (opioid/opioid-bupivacaine or bupivacaine), and the type of system used (externalized/internalized). In these comparisons, recent data from a companion paper (Nitescu et al., Clin J Pain 1998;14:17-28) were used as a reference to be compared with data from a literature review of different intraspinal treatment modalities in nonmalignant pain. Design: Prospective, cohort, nonrandomized, consecutive trial. Setting: Tertiary care center, institutional practice, hospitalized, and ambulatory care. Patients: Five groups according to treatment modality: (a) externalized, long-term intrathecal nylon catheters, connected to external, electronic infusion pumps (companion paper), n = 90; (b) internalized, long-term intrathecal catheters (Silastic®) connected to implanted SynchroMed® pumps, n = 330 (literature review); (c) externalized, short-term epidural catheters for temporary infusions, n = 565 (literature review); (d) externalized. long-term epidural catheters, n = 50 (literature review); (e) internalized, long-term epidural catheters, n = 111, connected to implanted systems: Port-A-Cath® injection ports, n = 58; Infusaid® pumps, n = 46; and SynchroMed® pumps, n = 7 (literature review). Interventions: In reviewing the literature, we found 21 studies that reported on the intraspinal (epidural or intrathecal) administration of opioids with or without local anesthetics (usually bupivacaine). These studies were analyzed with respect to the rates of the variables satisfactory pain relief (efficacy), failures, and technical complications. A rate is the number of observations of a variable divided by the number of patients or the number of catheters or infusion systems, as logically indicated (e.g., the numbers of complications, such as epidural abscess and meningitis, were related to the number of patients and those of catheter occlusion or leakage to the number of the catheters). The variables were expressed as the means of the rates of a variable from studies belonging to various treatment modalities: approach (epidural vs. intrathecal), duration (short vs. long term), drugs administered intraspinally (opioid vs. opioid and/or local anesthetic), and type of infusion system (externalized vs. internalized). Further, the sums of all observations of one variable in different studies with various treatment modalities were related to the corresponding sums of the patients (alternatively, catheters or implanted devices). The proportions of these sums were tested for significance in relation to treatment modality. Main Outcome Measures: Comparative rates of successful intraspinal treatment and its failures and complications.