Endoscopic Botulinum Toxin Injection for Refractory Enuresis Based on Urodynamic Assessment.

Purpose This study aimed to determine the urodynamic characteristics of refractory enuresis and explore whether they can be managed through differential endoscopic injection with botulinum toxin. Methods A total of 27 patients with nonmonosymptomatic enuresis who showed no response after conservative treatment for more than 12 months were included herein. Patients then underwent videourodynamic study and received a differential endoscopic injection of botulinum toxin within the same day. Reduced capacity, detrusor overactivity, and bladder neck widening were the three major abnormal findings assessed during the filling phase, while sphincter hyperactivity was the only abnormality assessed during the emptying phase. Intravesical or intrasphincteric injection of botulinum toxin was attempted according to videourodynamic study findings. Follow-up was conducted 1, 3, 6, and 12 months after treatment. Results The median age was 10 (7–31) years. Although 19 and 8 patients had preoperative diagnosis of overactive bladder or dysfunctional voiding, respectively, urodynamic diagnosis was different in more than half of them. Those showing detrusor overactivity benefited from intravesical botulinum toxin injection, whereas those with only sphincter hyperactivity benefited from both intravesical and intrasphincteric injections. Treatment resistance to botulinum toxin seemed to have been attributed to bladder neck widening. Time had no apparent effect on efficacy, which remained 6 months after the injection. More than 80% of the patients retained the benefits of injection after 1 year. Conclusions Videourodynamic study was useful in identifying reasons of refractory nonmonosymptomatic enuresis and helpful in determining appropriate sites of botulinum toxin injection.