Long-term intraspinal infusions of opioids in the treatment of neuropathic pain.

Long-term intraspinal infusions of opioid drugs are being increasingly utilized in patients with noncancer pain. Despite this, there is a lack of long-term information, including success and failure rates for pain relief and technical problems. During a 5-year period, 18 noncancer patients underwent implantation of programmable infusion pumps for long-term intrathecal opioid infusion. Patients had (a) neuropathic pain, (b) had failed or been ineligible for noninvasive treatments, and (c) obtained greater than 50% pain relief with intrathecal trial infusions of morphine sulfate or sufentanil citrate. A disinterested third-party reviewer evaluated patients at the most recent follow-up. Sixty-one percent (11/18) of patients had good or fair pain relief with mean follow-up 2.4 +/- 0.3 years (0.8-4.7 years). Average numeric pain scores decreased by 39% +/- 4.3%. Five of the 11 responders required lower opioid doses (12-24 mg/day morphine) and the remaining six patients required higher opioid doses (> 34 mg/day morphine). Failure of long-term pain relief occurred in 39% (7/18) despite good pain relief in trial infusions and the use of both morphine and sufentanil. Technical problems developed in 6/18 patients but appeared to be preventable with further experience. Long-term intrathecal opioid infusions can be effective in treatment of neuropathic pain but might require higher infusion doses.