RecruitingDevice studyTranscutaneous Tibial Nerve Stimulation (TTNS) Treatment in Spina Bifida Pediatric Patients With Neurogenic BladderThe purpose of this research study is to determine the effectiveness of a treatment called "transcutaneous tibial nerve stimulation" or "TTNS" in the treatment of urinary leakage for patients with spina bifida. This treatment involves electrical stimulation of a nerve by the ankle. Participants will complete urodynamic testing and questionnaires prior to the treatments. Participants will then complete 6 weekly treatments of TTNS. Participants will learn how to do the treatment in the clinic, and then can complete the treatments at home. For patients with a good response, the treatments may be continued for another 6 weeks, for a total of 6 weeks.