BACKGROUND: Sufficient accumulations of local anesthetics in the extrapleural space promotes effective access to several intercostal nerves and, consequently, analgesia. The total volume of leakage of these anesthetics from the space can depend on the technique of extrapleural catheter insertion which is chosen. METHODS: Twenty patients due for thoracotomy were randomly selected to be provided with postoperative pain relief 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 at a longitudinal lie in a cephalad direction, before the thoracic cavity was closed. 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 satisfactory to patients and thoracic surgeons. The average numbers of analgesic dermatomes obtained by pinprick tests, VAS, and Prince Henry pain scores were 5.2 0.5, 2.0 0.5 cm and 1.6 0.6, respectively. Changes in mean arterial pressure were insignificant, and heart rate increased at the postoperative hours of 1, 4 and 8 (P value < 0.05). FVC and FEV1 were restored to levels up to 67.2 and 71.0% of their preoperative values at the postoperative hour of 48. CONCLUSIONS: These results suggest that the technique of a catheter introduced at a longitudinal lie in a cephalad direction was effective and clinically useful for pain relief following thoracotomy regardless of some leakage of bupivacaine.