Intrathecal morphine for chronic benign pain.

In the treatment of chronic benign pain, the administration of an intrathecal opioid produces a potent analgesia without interfering with the motor and sensory functions of the lower extremities. An intrathecal opioid should be considered only when pain control with conventional oral and systemic administration is inadequate or is associated with unmanageable side effects. A trial period and a psychological evaluation are mandatory prior to implantation of a permanent device. About 40% of the patients need surgical revision for various complications. Hormonal changes may influence sexual behaviour. Catheter granulomas can form with high concentrations of morphine. Adjuvant drugs such as bupivacaine, clonidine and ketamine might be necessary to deal with the development of tolerance to morphine. The sophistication of available technology for intrathecal infusion today far exceeds our knowledge of the potential neurological effects of this treatment modality.