Neuraxial techniques for cancer pain: An opinion about unresolved therapeutic dilemmas

Background and Objectives. Epidural and intrathecal techniques are well est ablished for minimizing cancer pain. However, several issues remain unresol ved. Methods. A review of studies published in the last 10 years regarding neuraxial techniques in cancer pain management was made. The following issu es were assessed: appropriate indications; techniques and delivery systems; conversion from systemic to spinal administration; route and modes of admi nistration; choice of opioids, analgesic response and adverse effects of op ioids; use of local anesthetics; use of adjuvants; technical complications; and possible problems only recognized at home. Results. Indications for th e use of neuraxial opioids include patients treated with systemic opioids w ho received effective pain relief bur with unacceptable side effects or uns uccessful treatment despite escalating doses with sequential, strong opioid drug trials. The choice of exteriorized or implanted delivery systems is b ased on different clinical considerations. The use of externalized, tunnell ed intrathecal catheters has not been proven to be associated with higher r ates of complications, and they may be easier to place and use at home in d ebilitated patients late in the course of their disease. Intrathecal admini stration has a lower incidence of catheter occlusion, lower malfunction rat e, lower dose and volume requirements, and more effective pain control. Adv antages of continuous infusion techniques are more evident when using local anesthetics, because intermittent administration of bupivacaine often resu lts in motor paralysis and hemodynamic instability. Morphine appears to be the opioid of choice, and an epidural dose of 10% of the systemic dose is o ften used. Bupivacaine-induced adverse effects have been reported infrequen tly with bupivacaine doses less than 30-60 mg/d. Adjuvant drugs, such as cl onidine and neostigmine, may further improve analgesia. Varied ranges of te chnical complication rates have been reported in the literature, with most being associated with epidural catheters. Conclusions. A subcutaneous tunne lling and fixation of the catheter, bacterial filters, minimum changes of t ubings, weekly exit site care, site protection, and monitoring for any sign s of infection are suggested for advanced cancer patients. Areas still need ing clarification include the optimum use of spinal adjuvants, the appropri ate spinal morphine-bupivacaine ratio, methods to improve spinal opioid res ponsiveness, and long-term catheter management during home-care programs.