This is a prospective, multicentre observational study studying the learning curve of the HoLEP procedure, through auto-evaluation of the quality of the surgery by senior attending urologists introducing HoLEP in their current clinical practice. This is a single arm, not comparative study. The primary outcome is the ability of each surgeon to perform 4 HoLEP procedures successfully, according to a pre-defined surgical performance scale [varying from 0 to 5]. To be successful, a procedure must be scored 5/5. Each procedure is evaluated at the end of the surgical act by the surgeon himself. As secondary outcomes, the short term efficacy and safety parameters of the HoLEP technique will be evaluated through the following data prospectively collected: