• The use of IV line during treatment with fentanyl ITS will be evaluated. Therefore we will document (24h, 48h, EOT) the amount of patients who have an IV line and compare the actual usage of the IV line with the intended use of the IV line.
  

• Patient, physician and nurses' satifaction of treatment
  

The purpose of this study is to evaluate in daily clinical practice the safety and efficacy of a fentanyl Iontophoretic Transdermal System (fentanyl ITS) for management of moderate to severe acute pain in postoperative patients who have undergone elective spine or orthopaedic surgery. There will be a focus on the analysis of the use of IV lines and the administration of intravenous medication for opioid related side effects or for additional analgesia during the use of fentanyl ITS. Therefore we will document (at each time point) the amount of patients who have an IV line and compare the actual usage of the IV line with the intended use of the IV line. The exact moment of first oral intake as well as the exact moment of discontinuation of the IV line will be recorded, if applicable.Patients are expected to require parenteral opioids for at least 48 hours postoperatively. This study will also evaluate patients', nurses' and physicians' assessment of fentanyl ITS under routine conditions.All adverse events will be documented. The delayed occurrence of application side reactions after removal of the device will be followed-up. The study treatment phase can last up to 72 hours.

40 mg fentanyl transdermally per on-demand dose, each delivered over 10 min for a maximum of 6 doses/h (240 mg/h) for 24 h or a maximum of 80 doses (3.2 mg). Each system will inactivate at 80 doses or 24 h, whichever occurs first. A new system will be applied every 24 h unless the patient has used 80 doses in less than 24 h. In this case a new system can be applied earlier. This system will be changed again at the 24 h time point. A maximum treatment duration of 72 h is allowed.