The primary end-point is the change of Patient Perception of Bladder Condition (PPBC) at 4 weeks after the initial injection. If patients have a PPBC improved by two scales, they are considered as successfully treated, otherwise failed treatment. The subjective symptom score, quality of life score and urodynamic parameters will be compared at baseline and 4 weeks after BoNT-A injection within and between the treatment group and control groups. For the patients who do not have significant improvement 4 weeks after BoNT-A injections, a second injection with 100 units of BoNT-A will be performed at 4 weeks after the initial injection regardless the patient's initial grouping. These patients will be followed up at the same interval until the return of voiding dysfunction.