Spinal Morphine in Nonmalignant Chronic Pain: A Retrospective Study in 39 Patients

Abstract

It was the purpose of this study to retrospectively test the safety and efficacy of the use of intraspinal analgesics in a diverse population of patients with chronic nonmalignant pain. This study was conducted in 39 patients, refractory to conventional therapies for intrathecal therapy. Twenty-two patients had neuropathic pain and 17 had nociceptive pain. The mean follow-up of this patient population was 2.2 years with a range of 36 months to 6.5 years. Analgesia with intraspinal morphine, initial and final dose of intraspinal agents used, stability of morphine dose over time, and side effects and complications with or without bupivacaine and/or clonidine was assessed after 6 months of treatment, and at the end of study. After 6 months, three patients discontinued the study for differing reasons, 28 patients (77.8%) reported excellent results, and five patients (14%) reported good results. One patient reported no pain relief with intraspinal morphine and bupivacaine and five patients reported insufficient or no pain relief. At final assessment, 20 patients (55.6%) reported excellent results with no differences based on pain type or pain syndrome and eight patients (22.2%) reported good analgesia. Morphine doses remained stable throughout treatment, with an average dose of 2 mg per patient. Ninety-one percent of patients were satisfied with the method used and considered it superior to all previous therapeutic techniques tried, improving their quality of life. As for complications, one patient developed a clostridial infection during the immediate postoperative period which required pump removal and one patient developed severe urinary retention requiring system removal. There were three catheter obstructions (two in the same patient) and one catheter disconnection. Other patient-reported side effects were not considered significant by the authors to be mentioned here. After more than 6 years of experience with spinal infusion of morphine, either alone or admixed with other spinal analgesics, in patients with pain of nonmalignant origin, we consider the technique to be helpful in selected patients not responding to oral treatment or when untoward side effects exist with oral treatment. The advantages, as regards to analgesic efficacy and quality of life, clearly outweigh the drawbacks of the long-term use of spinal morphine.