Objective: We describe 2 cases of Horner syndrome after epidural test dose injections in thoracic surgery patients. The Horner syndrome was transient and did not recur with full epidural activation and infusion.

Case Report: Two patients undergoing thoracic surgery procedures received preoperative midthoracic epidural catheters for postoperative analgesia. Following the 3-mL 1.5% lidocaine test dose, a unilateral Horner syndrome was observed. No other signs and symptoms of high epidural blockade were seen, and the Horner syndrome subsequently resolved. After epidurogram confirmation of proper catheter position and at the conclusion of surgery, the epidural was activated with an appropriate bolus and infusion dose without recurrence of the Horner syndrome.

Conclusions: Two cases of Horner syndrome presenting after administration of an epidural test dose are reported. This uncommon initial finding could not be reproduced with subsequent epidural activation, perhaps suggesting that initial conditions within the epidural space had been altered. Successful utilization of neuraxial regional analgesia was achieved with careful postoperative monitoring of the patients.