Implanted drug delivery systems for spinal administration of morphine in cancer pain relief

The results of long term epidural and intrathecal use of opioids by drug delivery systems are compared in this study. Epidural ports (Periplant® or Cordis®) were implanted to 147 patients whereas intrathecal implant systems (PAR®, Secor, Cordis®) were implanted to 58 patients. The dose and concentration of morphine were adjusted according to the patients' report of pain intensity. Pain severity, pump or port function, spinal morphine requirements, adverse side effects were evaluated. Initial daily dose of morphine was 8.9±2.9 mg for epidural ports and 2.6±0.5 mg for intrathecal drug delivery systems. Mean duration of analgesia was 6.5±3.2 h in epidural ports whereas 12.8±4.1 h in intrathecal systems. Mean duration of epidural morphine treatment was 130.8±70.1 days. The drug delivery system remained with an average of 3.2 months in the intrathecal group. Most of the patients (80% of epidural ports and 90% of intrathecal pumps) had significant pain relief. Device-related complications in the epidural group were catheter occlusion (2.0%), disconnection (2.7%), infection (7.5%), skin necrosis (3.4 %), port damage (2.0%). Drug-related complications in the epidural group were nausea-vomiting (25.9%), constipation (25.9%), urinary retention (11.6%), pruritis (8.8%), burning pain on injection (12.2%), and headache (3%). Device-related complications in the intrathecal group were seroma (6.9%), infection (3.4%), skin necrosis (1.7%). Drug-related complications in the intrathecal group were nausea-vomiting (17.2%), constipation (10.3%), urinary retention (8.6%), pruritis (6.9%), burning pain on injection (1.7%), headache (10.3%), and respiratory depression (3.4%). Implantable opioid delivery systems are useful adjuncts for cancer pain management. Proper selection of patients and delivery systems, good patient education and communication, good surgical and sterility techniques, and knowledge of risks and complications will increase the success of these systems.