Exclusion criteria Anamnestic exclusion criteria are all contraindications for epidural anaesthesia (e.g. neurological deficit, skin infection of the puncture site, diseases leading to neurological impairment such as diabetes, coagulation impairment). Non-competent and non-cooperative patients as well as pregnant and breast-feeding women are also to be excluded. Same applies for patients with medicament- and drug abuse or problems in communication or those participating in parallel in another clinical study with experimental drugs or devices.