Background and Aims Epidural catheter migration is a known complication, but migration to subarachnoid space is extremely rare, with only a few case reports in the literature.

Methods This case describes the intrathecal migration of a previously functioning epidural catheter.

Results 28 years old, GIP0 without relevant medical history, was admitted to the labor ward. After an unsuccessful attempt, the epidural catheter was placed at L3-L4 intervertebral space, using an 18G Tuohy needle with loss-of-resistance to saline technique. The aspiration test was negative. 8 ml ropivacaine 0.1% and 10μg sufentanil were given, with satisfactory pain relief. The epidural pump was programmed to administer a PIEB of 8 mL of 0.1% ropivacaine every hour with PCEA boluses of 5 mL. She was hemodynamically stable and without motor block.

Five hours later, she complained about motor block of lower extremities. The sensory level to cold was T4-T5. The epidural pump was stopped. A colorless liquid was aspirated through the catheter and the glucose test was compatible with liquor.

After reversal of motor block, the intrathecal catheter was successfully used to provide labor analgesia.The delivery was uneventful. She had no post-dural puncture headache or other postpartum complications.

Conclusions Since the epidural catheter is hardly able to penetrate an intact dura, in our patient there was probably an inadvertent dural puncture on the first attempt, with subsequent migration through the dura hole. Another possibility is the initial placement in subdural space, with pain relief for the first PIEB doses, and then migrated through the arachnoid mater into the intrathecal space.