Suspected migration of cervical epidural catheter into the brainstem after a difficult catheter insertion.

We report a case of diplopia during continuous epidural injection presumably caused by catheter migration. A 61-year-old woman underwent shoulder surgery under general anesthesia with cervical epidural anesthesia. The epidural catheter was placed in the C6-C7 epidural space with some difficulty before general anesthesia. The depth of the catheter placed under the skin was 10 cm. On POD 2, the patient noticed diplopia and developed dysarthria despite of good pain control so far. She complained of sudden headache after the rate of continuous epidural infusion was increased to relieve postoperative pain. Computed tomography and T2-weighted cerebral magnetic resonance imaging revealed an air image and surrounding edema in the pons. Diplopia and dysarthria disappeared after ceasing continuous epidural injection. A 15-cm-long mark under the skin and leak of colorless clear fluid from the puncture site were noted at removal of the catheter. On POD 13, diplopia recurred, which improved gradually. On the 9-month radiologic follow-up, we considered that the symptoms on POD 2 were caused by migration of the epidural catheter into the pons and that her later diplopia was induced by intracranial hypotension syndrome. One should be aware that such an unexpected migration of the catheter can occur following a difficult insertion.