Transient lower limb pain following accidental thoracic subarachnoid insertion of an epidural catheter

Transient sensory disturbances, including dysesthesia or neurologic deficits in the lower extremities or buttocks have been described as complications of neuraxial anesthesia. We report a case of transient lower limb pain following the accidental placement of an epidural catheter into the thoracic subarachnoid space. A 31-year-old woman was scheduled to undergo laparoscopic myomectomy. An epidural catheter was accidentally inserted subarachnoid at the T12-L1 intervertebral space with a 2-ml test dose of 2% lidocaine, and was promptly removed. Fulgurant pain and allodynia extending over the L2-5 areas of the left lower limb and buttock started immediately postoperatively. We treated the persistent pain in our patient with epidural infusion of local anesthetics and steroids during her hospital stay, and with carbamazepine and a tricyclic antidepressant after her discharge from the hospital. All signs of allodynia had disappeared on postoperative day 25. Sagittal and axial T2-weighted magnetic resonance imaging (MRI) at the Th12 level revealed a small high-intensity area without mass effect in the ipsilateral dorsal column. The patient's clinical course and MRI diagnosis suggested the inhibition of descending inhibitory pathways resulting from a lesion of the spinal cord as the possible etiology of the transient lower limb pain and allodynia.