Long Term Intrathecal Administration of Morphine: A Comparison of Bolus Injection via Reservoir with Continuous Infusion by Implanted Pump

Abstract

Twenty-six cases of chronic intrathecal morphine administration are described: 19 cases utilizing the Spinalgesic injectable subcutaneous reservoir and 7 cases utilizing the Infusaid implanted infusion pump. In 25 cases, the morphine was delivered into the spinal subarachnoid space, and in 1 case of thalamic pain it was delivered into the temporal horn of the ipsilateral cerebral ventricle. The average duration of usage of the system was 132 days. The efficacy of the method was excellent: 23 of 26 patients used no other analgesics or only minor ones such as aspirin, paracetamol, or dextropropoxyphene. The complication rate was low, with no infections under the author's care, and only 4 catheter blockages (1 by tumor). There have been no complications in the 7 patients with implanted pumps. From this experience, the author concludes that the implanted pump is now the method of choice in all patients who can afford it and for whom the life expectancy outside an institution is in excess of 60 days. A special and relatively absolute indication for the pump is the situation of pain in the arm, head, or neck areas, in which case the constant morphine levels likely to be achieved with the pump may prevent failure of the method due to intractable nausea or emesis. The subcutaneous reservoir is otherwise to be preferred if the patient's disease is progressing rapidly, if the patient is already institutionalized and likely to remain so, or where the cost of the implanted pump would cause hardship. Either method of delivery of morphine to the subarachnoid space can provide incomparable analgesia without clouding of consciousness, with a very low complication rate. (Neurosurgery 21:484-491, 1987)