| The Doctor’s Advocate | Second Quarter 2008 |
Medtronic Neuromodulation SynchroMed and IsoMed Implantable Infusion Pumps
by David B. Troxel, MD, Medical Director, Board of Governors
Formation of an inflammatory mass (granuloma) at or near the distal tip of intrathecal catheters has been reported with the intrathecal infusion of opioids, baclofen, pharmacy-compounded drugs, and other pharmacological admixtures. There is an association with use of morphine sulfate, other opioids, and analgesic admixtures—particularly when administered in relatively high doses and/or high concentration. The reported incidence of inflammatory mass formation is as high as 3 percent in one study. Some cases occurred within six months, while others occurred as long as 10 or more years after starting opioid therapy. The table below summarizes the frequency of symptoms reported through September 2007. The most frequently reported symptoms are:
- decreased therapeutic response/inadequate pain relief (reported in 33.5 percent of patients),
- pain (reported in 32.6 percent of patients), and
- neurological deficit/dysfunction (reported in 17.4 percent of patients).
Inflammatory mass formation has been associated with a wide range of doses and concentrations of opioids, and no dose and/or concentration of morphine sulfate can be considered completely free of risk. The risk appears to be cumulative over time and increases with higher concentrations of opioids. Therefore, intrathecal opioids should be administered to achieve adequate analgesia for as long as possible at the lowest effective dose and concentration.
Recommendations for Patient Management
Individual patient susceptibility to inflammatory mass cannot be predicted. Diligent patient management and increased awareness of inflammatory mass symptoms are essential. In patients with new neurological signs or symptoms, consider neurosurgical consultation and the prompt performance of an imaging procedure to confirm or rule-out an inflammatory mass.
Summary
- When administering intrathecal opioids, administer the lowest effective dose and concentration.
- In patients treated with intrathecal baclofen therapy, monitor them to identify the prodromal clinical signs and symptoms of inflammatory mass, especially if using pharmacy-compounded drugs or baclofen admixtures that include opioids.
- In patients with new neurological signs or symptoms, consider neurosurgical consultation and prompt performance of an imaging procedure to confirm or rule-out an inflammatory mass.
For Assistance and a Sample Informed-Consent Document
This alert can be found on our Web site at www.thedoctors.com/psalerts. For a copy of the sample informed-consent document, visit our resource center at www.thedoctors.com/consent.
Medtronic Neuromodulation Technical Services can be reached at (800) 707-0933. Additional information, including links to references and abstracts, can be found at www.medtronicconnect.com. Medtronic’s January 2008 letter to physicians about inflammatory mass can be found at www.medtronic.com/im.
Summary of Symptoms Reported for Cases of Inflammatory Mass
Click to view a larger image in PDF (13.5K)
Material in this Risk Management Alert was adapted from information contained in Medtronic’s January 2008 letter to the health care community.
About the Author
David B. Troxel, MD, is medical director of The Doctors Company. Dr. Troxel is clinical professor emeritus in the School of Public Health at the University of California at Berkeley. He is past president of the American Board of Pathology and the California Society of Pathologists.
The Doctor’s Advocate is published by The Doctors Company to advise and inform its members about loss prevention and insurance issues.
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