All the patients were vaccinated against pneumococci with Pneumovax 23 (Merck & Co Inc., Whitehouse Station, NJ, USA) two weeks before the operation. All patients received antibiotic prophylaxis (Sulbactam and ampicillin 1 g, intravenously). All patients received general anesthesia during surgery and a standardized analgesic regimen. HALS and OS were performed by the same surgical team. Post-operative analgesia was achieved by patient-controlled analgesia via a pump containing a standard narcotic analgesic solution. All patients received the same non-steroidal antinflammatory drug (lornoxicam 8 mg, twice a day, intravenously) and the same narcotic analgesic (pethidine 50 mg, twice a day, intramuscularly) on the first and second postoperative day.