1. Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Centre, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands
2. Department of Pharmacology and Toxicology, Maastricht University Medical Centre, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
3. Department of Methodology and Statistics, Maastricht University Medical Centre, P.O. Box 616, 6200 MD, Maastricht, The Netherlands