BACKGROUND: Several dermatomes around the skin wound may need to be bldegrees Cked in order to provide pain relief with intercostal bldegrees Ckade after thoracotomy and chest tube insertion. METHODS: Twenty patients who had undergone elective thoracotomy were selected to provide continuous intercostal nerve bldegrees Ck by an extrapleural approach. Before the thoracic cavity was closed, appropriate spaces between parietal pleura and intercostal muscle were made with surgical dilators under direct vision. An epidural catheter was introduced cephalad with the distal end uppermost and in a caudal direction making a U-turn lowermost in the spaces. Bupivacaine 0.25%, with 1 : 200,000 epinephrine was injected in a 10 ml dose about 20 minutes before the end of anesthesia, and infused at a rate of 0.88 mg/kg/hour for 1 hour, 0.35 mg/kg/hour for 23 hours and 0.3 mg/kg/hour for the second day postoperatively. RESULTS: The degree of analgesia with coughing and deep breathing was satisfied with patients and thoracic surgeons. Average numbers of analgesic dermatomes obtained by pinprick test, VAS and Prince Henry pain score were 5.6+/-0.3, 1.8+/-0.3 cm and 1.6+/-0.3 respectively. Changes in mean arterial pressure showed insignificantly and heart rate increased at the postoperative hour of 1 and 4(P value<0.05). FVC and FEV1 were restored up to 71 and 75% of preoperative value at the postoperative hour of 48. CONCLUSIONS: These results suggest that continuous intercostal nerve bldegrees Ck through the extrapleural approach was effective and clinically useful for pain relief following thoracotomy.