Magnetic resonance imaging findings after uneventful continuous infusion neuraxial analgesia: a prospective study to determine whether epidural infusion produces pathologic magnetic resonance imaging findings.

BACKGROUND: Magnetic resonance imaging (MRI) is considered the preferred diagnostic tool to determine whether postepidural neurologic symptoms are due to hematoma or abscess. However, there is currently no published information regarding the normal appearance of a MRI after a continuous epidural infusion. In this prospective cohort study, we defined the characteristic appearance of MRI findings after uneventful epidural analgesia. METHODS: Thirty women were prospectively enrolled to undergo a lumbar MRI after labor and delivery. The study group consisted of 15 women who received neuraxial analgesia with a combined spinal epidural technique followed by continuous epidural infusion, whereas the control group included 15 women who delivered without receiving neuraxial analgesia. All patients received a MRI within 12 h of delivery via a 1.5T scanner. MRIs were reviewed by two neuroradiologists who were blinded to the patient's study group allocation and asked to document the presence or absence of fluid collection, air collection, or soft tissue abnormalities. RESULTS: There were no radiologically significant fluid collections, hematomas, or mass effects noted on the thecal sac of any of the 30 MRI studies. A small amount of epidural air was seen in 77% of MRI studies after epidural analgesia, but there was no indention on the thecal sac. CONCLUSIONS: The lack of significant collections or mass effects seen in the MRIs of our patients after continuous infusion of epidural analgesia suggests that the presence of these findings in a patient with new neurologic symptoms after administration of epidural analgesia should be considered pathologic and warrant immediate attention.