SynchroMed II Intrathecal Pump Memory Errors Due to Repeated Magnetic Resonance Imaging

Cancer patients with severe refractory pain are often managed with implantable drug delivery systems (IDDS). The only drugs with US Food and Drug Administration approval for intrathecal use are morphine, ziconotide, and baclofen. Other drugs used and mixed include, hydromorphone, bupivacaine, sufentanil, and fentanyl. These patients often undergo magnetic resonance imaging (MRI) for disease-related monitoring and diagnoses. Although uncommon, IDDS can fail to resume normal functioning after MRI, potentially causing complications. The magnetic field of an MRI will temporarily stop the rotor of the pump motor and suspend drug delivery for the duration of the MRI exposure. The pump should resume normal operation when removed from the MRI magnetic field, but there is a potential for a delay in the return of proper drug infusion and a delay in the logging of motor stall events after an MRI in the SynchroMed II pumps. A 57-yearold man who underwent multiple MRIs with an implanted IDDS experienced 2 separate memory failures leading to multiple complications. After the first pump malfunction, the patient developed withdrawal symptoms and was treated in the emergency department. The first time, a memory reset resolved the problem. The second time, 29 months later, the patient was admitted to the hospital to manage withdrawal symptoms and the pump had to be exchanged with a new device. Post-MRI pump interrogation should be performed on all patients with IDDS to ensure proper functioning of the pump. Special attention should be paid to patients receiving baclofen, as acute withdrawal can be very serious, even deadly. Key words: Cancer pain, MRI, IDDS, SynchroMed II, baclofen, withdrawal, stall.