[Analgesia with an implanted device for repetitive intrathecal injections of morphine]

The use of intraspinal narcotics has been widely accepted as pain relief treatment for intractable cancer pain. Intraspinal low doses of morphine induce a potent selective long lasting analgesia. To avoid repetitive lumbar puncture, a drug delivery device was surgically implanted in 41 patients. The surgical procedure is described. The mean amount of morphine needed was 1.48 +/- 0.25 mg per day at time of surgery, rising to 6.86 +/- 1.47 mg per day after a mean survival time of 65 days. Tolerance became a major problem in 18 patients, which nearly all were selected at a late disease stage and previously received narcotics for pain relief. However, no clear-cut prognostic factor had a predictive value for the appearance of tolerance. In some cases, it could be successfully treated by intraspinal injection of local anaesthetics or clonidine. CSF leakage was noted in 11 patients; this was a challenge for us, as no other authors reported such a high rate for this complication. Aseptic meningitis was noted three times. In all cases but one, the symptoms resolved with appropriate treatment.