Abstract: AIM: To evaluate the effectiveness and safety profile of implanted intrathecal drug (morphine) delivery system in treatment of patients with intractable pain.METHODS: 4 patients suffering from intractable pain were treated with intrathecal morphine using implanted drug delivery system for pain control.The clinical data were recorded and analyzed retrospectively.RESULTS: These patients included 2 cases of cancer pain, 2 cases of benign back pain after back operation (Failed Back Syndrome).All of them had tried big doses of oral or intravenous strong opioid, with poor pain relief and intolerable side effects.Before the implantation, all patients had trial test, i.e, certain amount of morphine (referring to the daily systemic dosage) were injected into intrathecal or epidural space to test whether the pain relief would be satisfactory without severe side effects.The VAS scale decreased up to 50% or more after the intrathecal morphine, suggesting the positive result of trial test.They were then operated and the intrathecal drug delivery systems were implanted.After the operation, the intrathecal morphine dosage was adjusted according to the pain VAS scale as well as the side effect profile.All the patients showed significant pain relief without serious side effect.CONCLUSION: The implanted intrathecal drug delivery system infusing analgesics directly into the target area (spinal cord and brain) proves to be effective for intractable pain control and have fewer side effects.As an invasive and expensive technique, its application should be cautious and trial tests should be done before the implantation.

Key words: intractable pain, implanted drug delivery system, morphine, opioid, trial test