Recent years have seen the importance of early mobility and respiratory toilet to minimise complications and hospital stay. Newer methods of pain relief with fewer systemic effects have become even more important. Continuous wound infiltration catheters (CWI's) aim to deliver local anaesthetic agents directly into the wound (4). This technique goes back to 1994, and has been established in this hospital and is used in a non-structured manner in thoracic surgery. Recent studies have demonstrated that the addition of dexamethasone (a steroid) to local anaesthetic agents in similar nerve blocks significantly improves the analgesic affect and prolongs the duration of the analgesia. To the best of the investigators knowledge this has not been tested in a thoracic surgery cohort of patients, though it has been tested safely and effectively in the thorax in healthy volunteers and in postoperative analgesia in abdominal and musculoskeletal post op patients. The investigators aim is to assess whether the addition of perineural dexamethasone to the local anaesthetic in CWI's is superior to the local anaesthetic alone in thoracic post operative patients, and at which dose. They also want to assess the levels of pain experienced 1 month post op to evaluate the potential effect of dexamethasone on post thoracoscopy pain syndrome.