A Prospective, Randomized Trial of Intrathecal Injection vs. Epidural Infusion in the Selection of Patients for Continuous Intrathecal Opioid Therapy.

The objective of this study was to compare the cost and safety of intrathecal injection (IN) vs. epidural infusion (CE) trial and to provide a preliminary assessment of the prognostic value of each in the selection of patients for long-term continuous intrathecal opioid therapy (CIOT). Thirty-seven patients with chronic nonmalignant pain who were being considered for CIOT were randomized to morphine trial by IN or CE. Analgesic response and complications were monitored throughout trial. Sixty-seven percent of IN (12/18) and 79% (15/19) of CE subjects reported good pain relief (defined as ≥ 50% pain reduction) and were implanted with a permanent infusion system. Eighty-nine percent (24/27) of subjects provided six-month CIOT follow-up data. Cost of trial and health care utilization during six months of CIOT were compared between groups. Analgesic and functional response during CIOT was also compared between IN and CE groups. The cost of IN trial was significantly less than CE trial (p < 0.001). Complications were generally mild in both groups, although opioid-related side effects tended to be more common in the IN group. Successful pain relief after six months of CIOT was reported by 10 (60%) and 14 (64%) patients who underwent IN and CE trial, respectively (p = 0.32; Fisher's exact test). There was no difference between IN and CE groups in McGill Pain rating, quality of life (VAS), mood (Profile of Mood States), or function (Sickness Impact Profile) after six months of CIOT. We conclude that intrathecal injection is a safe procedure for use in selection of patients for CIOT and is less costly than epidural infusion. Differences in pain and functional response to long-term opioids among patients selected by either trial method are not large.