Inclusion Criteria:  Proven dysfunctional voiding according to the ICCS criteria Signed informed consent by parents motivated to participate in the study Previous treatment by pediatricians in primary care with timed voiding, hydratation and constipation management for three months with no significant success  Exclusion Criteria:  Neurological disorders Monosymptomatic nocturnal enuresis Mental retardation Structural abnormalities of the lower urinary tract -