['We assessed the generation of vesicoureteral reflux before and after injection of botulinum toxin A into the trigone of patients with nonneurogenic overactive bladder, and evaluated its short-term efficacy.', 'Adults with nonneurogenic overactive bladder resistant to behavioral treatments, pelvic floor exercises, medication and neuromodulation were included in the study. The initial evaluation (history, physical examination, 3-day urinary diary, V8 score, flowmetry and post-void residual) was repeated 6 weeks after botulinum toxin A injection. Videourodynamic study was performed 1 hour before injection and 6 weeks later. Botulinum toxin A (200 units) was injected into the detrusor in 10 sites over the bladder base including the trigone. The primary outcome was the presence or absence of vesicoureteral reflux before and 6 weeks after botulinum toxin A injection. The secondary outcomes were clinical and urodynamic parameter changes. Values were compared using the Wilcoxon test.', 'A total of 12 women were enrolled in the study (median age 76 years). The duration of symptoms was 7.5 years. One patient was excluded from analysis because of a urinary tract infection. There were 10 women with no vesicoureteral reflux at baseline and 1 had bilateral vesicoureteral reflux (grade 2 right, grade 1 left). At 6 weeks there was no induced vesicoureteral reflux and the patient with vesicoureteral reflux at baseline showed no change in vesicoureteral reflux grade. No local or systemic side effects related to botulinum toxin A were reported. In terms of efficacy, at direct questioning 6 weeks after treatment 4 of 11 patients reported an improvement that made them ask for another injection.'] Do botulinum toxin type a injections into the trigone to treat idiopathic overactive bladder induce vesicoureteral reflux?