Intravesical botulinum type A toxin injection in patients with overactive bladder: Trigone versus trigone-sparing...

Botulinum toxin type A (BTX-A) has been successfully used in the treatment of patients with overactive bladder (OAB) symptoms refractory to anticholinergic therapy, with most studies performing trigone-sparing detrusor injections. Increasing evidence suggest that sensory nerve dysfunction contributes to the pathophysiology of OAB and, for this reason, targeting the afferent innervation of the bladder trigone during injection may provide clinical benefit.

We conducted a pilot study to assess the benefit of trigonal-inclusion during BTX-A injection. A total of 40 patients with OAB refractory to anticholinergic treatment received trigone or trigone-sparing injection of BTX-A. Patients were evaluated using UDI-6 and IIQ-7 questionnaires prior to the BTX-A applications, at 3 weeks and 6 months after treatment.

At 3-week follow-up, 15/24 (63%) and 10/16 (63%) patients showed improvement of symptoms in the trigone versus trigone-sparing groups, respectively. Combined 3-week UDI-6 and IIQ-7 scores improved from 37.3 prior to treatment to 27.4 (p < 0.05) and 35.5 to 27.2 (p < 0.05) in the trigone and trigone-sparing groups, respectively. Six-month follow-up demonstrated continued but diminished levels of symptom improvement when compared to pre-treatment and 3-week symptom scores. Improvement in symptom scores between the trigone and trigone-sparing groups was not significant.

No significant difference in symptom score or treatment response was noted between the trigone and trigone-sparing groups. Further study using pre- and post-operative urodynamic study is needed to evaluate possible benefit to trigonal injection in a select sensory urgency cohort, and to assess for urodynamic improvement following trigonal injection.