Methods. This is a retrospective analysis of FBSS patients with chronic intractable back pain implanted with IT pumps delivering hydromorphone and bupivacaine. Results. A cohort of 57 (26 males, 31 females) consecutively implanted FBSS patients was analyzed. The average age at implant was 65.4 years. Average pain scores were 8.4 +/- 0.2 (pre-implant), 4.9 +/- 0.4 (6 months), 5.2 +/- 0.5 (12 months), and 4.3 +/- 0.5 (24 months). Average oral opioid doses in morphine equivalents were 56 +/- 10 mg/day (pre-implant), 12.0 +/- 3.5 mg/day (12 months), 15 +/- 6 mg/day (24 months). Average IT hydromorphone doses were 79 +/- 6.8 mcg/day (at implant), 184 +/- 22 mcg/day (6 months), 329 +/- 48 mcg/day (12 months), and 487 +/- 80 mcg (24 months). IT hydromorphone dose escalation from baseline was 133% (6 months vs baseline), 78% (12 months vs 6 months), and 48% from 12 months to 24 months. Average IT bupivacaine doses were 5.8 +/- 0.3 mg/day (implant), 9.5 +/- 0.6 mg/day (6 months), 12.2 +/- 0.7 mg/day (12 months), and 12.6 +/- 0.9 mg/day (24 months). Conclusion. IT hydromorphone and bupivacaine are effective in treating chronic pain of FBSS, as demonstrated by the reduction of pain intensity and oral opioid consumption. However, an IT dose escalation phenomenon was observed, although at a reduced rate compared with what had been previously reported in the literature. It is possible that the local anesthetic combination delivered via a patient-activaed bolus device is an important factor. Despite demonstrating effectiveness, the clinical utility of myPTM-optimized IT therapy remains limited by a lack of prospective, placebo-controlled trials and comparative effectiveness research.
