Outcome of intrathecal opioids in chronic non-cancer pain.

Eighty-eight patients (58 women and 30 men; mean age 53.4 years) with chronic non-cancer pain present on average for 9.8 years were evaluated following treatment with intrathecal opioids for an average duration of 36.2 months. Outcome measures were global pain relief, physical activity levels, medication consumption, work status, intrathecal opioid side-effects, proportion of patients who ceased therapy and patient satisfaction. The most common diagnosis in this group was lumbar spinal or radicular pain after failed spinal surgery (n= 55, 63%). At the time of follow-up, mean pain relief was 60% with 74% of patients (36 of 49) reporting increased activity levels. Oral medication intake was significantly reduced (Medication Quantification Scale Score prior to implantation 31.0+/-2.6 and at follow-up 12.7+/-1.4; n= 48; p< 0.0001). These gains were not accompanied by a change in work status (43 of 50 working age patients not working at follow-up). There were frequent reports of opioid side-effects, including sexual dysfunction and menstrual disturbance. Technical complications occurred with the drug administration device, most often catheter related, requiring at least one further surgical procedure in 32 patients (40%). Patient satisfaction with intrathecal opioids was high, with 45 of 51 (88%) reporting satisfaction. Mean intrathecal morphine dose increased from 9.95+/-1.49 mg/day (mean+/-SEM) at 6 months to 15.26+/-2.52 mg/day 36 months after initiation of therapy. Drug administration systems were permanently removed in five patients (6%). Intrathecal opioid therapy appears to have a place in the management of chronic non-cancer pain. Therapy does not seem to be significantly inhibited by the development of tolerance.