Outcomes and complications of continuous intraspinal narcotic analgesia for cancer pain control.
Preliminary reports of continuous intraspinal morphine analgesia have been enthusiastic regarding the resultant cancer pain control. Reports of continuous intraspinal infusion have not documented the duration of useful analgesia, need for concomitant analgesic therapies, or complication rates. Thus, the overall outcomes and complications of six chronic intrathecal and eight epidural morphine infusions were analyzed in the first 14 cancer pain patients implanted with continuous intraspinal morphine infusion reservoirs at this clinic. A five-point scale was used to assess the analgesic therapy required to maintain pain control during three consecutive intervals of intraspinal morphine infusion (zero to two months, two to six months, after six months). Comparison with pre-implant narcotic requirements revealed equal or reduced narcotic use for up to six months of therapy, with a definite trend toward escalation of intraspinal narcotics, systemic analgesia, and adjunctive procedures after two months. This occurred most likely due to narcotic tolerance and disease progression. Failure of pain control was the rule with continuous intraspinal morphine after six months. Three patients ultimately required neurolytic blocks. No clear difference was found in pain control requirements between epidural and intrathecal morphine infusion. No infection or respiratory depression occurred as a direct result of the intraspinal morphine implanted system.