Methods: Ninety-seven patients (86 males, 11 females; mean age 56.37 years; range 34 to 86 years) were included in this prospective and randomized study. Patients were randomized into two groups to undergo either ON-Q elastomeric pump system (group 1, n=50) or thoracic epidural analgesia (group 2, n=47) for 24 hours. In both groups, continuous 0.125% bupivacaine infusion was performed from a catheter at a rate of 0.1 mL/kg/hour. Intravenous morphine was provided to all patients through patient controlled analgesia method. Postoperative pain was evaluated with visual analog scale during rest and coughing at baseline and postoperative first, sixth, 12^th, and 24^th hours.

Results: Although visual analog scale rest and coughing scores of group 1 at first, sixth, 12^th, and 24^th hours were significantly higher than group 2, its baseline values were similar to group 2. Total local anesthetic consumption of group 2 was higher than group 1. Although hypotension was not observed in any patient in group 1, significant hypotension was observed in seven patients (14.9%) in group 2. The incidences of nausea and vomiting were 4% (n=2) in group 1 and 17% (n=8) in group 2.

Conclusion: Thoracic epidural analgesia provides superior analgesia compared to ON-Q elastomeric pump system in pain treatment after thoracotomy. Still, having lesser incidence of hypotension and easier technical application, ON-Q elastomeric pump system may be considered as an alternative method to thoracic epidural analgesia.