Extensive sensory block caused by accidental subdural catheterization during epidural labor analgesia.

A 32-year-old parturient requested epidural analgesia for labor. A lumbar epidural block was performed at the L1-2 interspace. Thirty minutes after the loading dose of the local anesthetic mixture, she suffered numbness in both arms and high sensory block up to the C6 dermatome without significant motor blockade. The retained epidural catheter was later confirmed radiologically to be in the subdural space. Accidental subdural catheterization is a rare complication of epidural block. Due to the smaller potential space, a subdural injection usually produces a high level block disproportional to the volume injected. Thus, patients receiving epidural block should be closely monitored following injection of local anesthetics regardless of the concentration or volume administered.