RESUMO
BACKGROUND: Magnetic resonance imaging (MRI) of the spine is the preferred diagnostic tool for pathologic conditions affecting the spine. However, in patients receiving epidural corticosteroid injection (ESI) for treatment of spinal diseases, there is a possibility of misreading of MR images because of air or fluid in the epidural space after the injection. Therefore, we defined the characteristics of abnormal changes in MRI findings following an ESI in patients with low back pain. METHODS: We reviewed the medical records of 133 patients who underwent MRI of the lumbar spine within 7 days after ESI between 2006 and 2015.All patients were administered an ESI using a 22-gauge Tuohy needle at the lumbar spine through the interlaminar approach. The epidural space was identified by the loss of resistance technique with air. RESULTS: The incidences of abnormal changes in MRI findings because of ESI were 54%, 31%, and 25% in patients who underwent MRI at approximately 24 h, and 2 and 3 days after ESI, respectively. Abnormal MRI findings included epidural air or fluid, needle tracks, and soft tissue changes. Epidural air, the most frequent abnormal finding (82%), was observed in 41% of patients who underwent MRI within 3 days after injection. Abnormal findings due to an ESI were not observed in MR images acquired 4 days after ESI or later. CONCLUSIONS: Pain physicians should consider the possibility of abnormal findings in MR images acquired after epidural injection using the interlaminar approach and the loss of resistance technique with air at the lumbar spine.
RESUMO
Epidural catheter migration is a well-known cause of failed anesthesia and complications. One of the factors that affect catheter movement is when patients change their position after skin fixation. We report a case of an epidural catheter placed without evidence of intravascular or subdural insertion that produced an insufficient block. A 36-year-old woman presented for ankle surgery under epidural anesthesia. Epidural block was conducted at the L3-4 intervertebral space with a catheter threaded 3 cm into the epidural space with the patient in a back flexion and lateral position. The total volume of injected anesthetic was 28 mL, including a 3-mL test dose. The final anesthesia level was L1. The planned operation was completed without a pneumatic tourniquet. A postoperative C-arm fluoroscopic image revealed that 1 side hole of the catheter had moved out of the epidural space. We think that a positional change after catheter fixation was the reason for catheter outmigration leading to insufficient analgesia, which was incompatible with the amount of local anesthetic injected.
