The minimal clinically relevant difference the study is looking for, is a Visual Analog Pain score difference of 3. The common standard deviation was estimated from a similar study by Caviggioli et al. in 2011, and set to be 2.96 on the Visual Analog Pain scale. We assume that our standard deviation (SD) will be the same. Using the following formula: N = (Za + Zb)2 x SD2 / dif2 where Za and Zb are the standardized normal deviations corresponding to the selected levels of significance, SD is Standard Deviation and dif is the minimal clinically relevant difference the study is looking for. The result is 16 patients in each arm, totalling 32 patients, when the significance level is set at 5% and the power of the study is set to 80%. Statistical analyzes will be performed in collaboration with a biostatistician from the Health Sciences Institution, Aarhus University, Denmark.