Korpi, Tomi Paavo TuomasUniversity of Helsinki, Päijät-Hämeen Keskussairaala, Helsinki University Hospital Catchment AreaResearcher, Research Assistant, Physiotherapist-Rantala, ArjaOulu University of Applied SciencesPrincipal LecturerAnxiety, Children, Day Surgery, Fear, Gamification, Gamified Mobile Health Intervention, Meta-analysis, Non-pharmacological Pain relief Methods, Pain, Pain Assessment, Parental Anxiety, Qualitative Studies, Randomized Controlled Trial, Systematic Review