Horner syndrome after unintended subdural block. A report of 2 cases.

Horner syndrome is considered a common finding after epidural analgesia or anesthesia in obstetric patients. Conversely, Horner syndrome is very uncommon in nonobstetric patients. We report 2 cases of Horner syndrome after attempted epidural lumbar anesthesia in 2 patients undergoing peripheral vascular surgery. Spinal fluoroscopy with contrast medium showed subdural catheterization in both cases. Horner syndrome after lumbar epidural anesthesia can be an indicator of inadvertent subdural catheter placement.