For each patient, utilisation of health care services will be recorded prospectively, using Case Record Forms, including urodynamic testing, surgery for SUI, re-operations, medical treatment for detrusor instability, care for urinary incontinence, and care for urinary retention. By multiplying these volumes of care with unit cost prices, direct medical costs incurred by SUI during the follow up period will be calculated for each patient. For unit cost prices, national guidelines will be used (CVZ, 2004). For costs of care for urinary incontinence and urinary retention, data from the literature will be used, converted to 2006 prices. We incorporated the health related quality of life questionnaire euroqol 5D in our study to be able to calculate QALYs (quality-adjusted life-years), which is a measure of health outcomes. A QALY is the change in quality of life induced by the treatment multiplied by the duration of the treatment effect and it provides the number of QALYs gained. QALYs can then be related to medical costs to arrive at a final common denominator of cost/QALY. This parameter can be used to compare the cost-effectiveness of the treatment.