Trigonal injection of botulinum toxin A in patients with refractory bladder pain syndrome/interstitial cystitis

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic disease without an effective treatment, characterized by pain during bladder filling. Most nociceptive bladder afferents course in the trigone.

To evaluate efficacy and tolerability of trigonal injection of botulinum toxin A (BoNTA) in patients with BPS/IC. Urine concentration of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were also evaluated.

Women with refractory BPS/IC were included in an open, exploratory study.

Under sedation, 100 U of BoNTA (Botox) were injected in 10 trigonal sites (10 U per 1 ml saline). Retreatment was allowed 3 mo after injection.

Pain, urinary frequency, O'Leary-Sant score (OSS), quality of life, (QoL), and urodynamic testing at 1 and 3 mo and every 3 mo thereafter. Urine NGF and BDNF were assessed at the same points. Patients who were retreated were evaluated every 3 mo.

All patients reported subjective improvement at 1- and 3-mo follow-up. Pain, daytime and nighttime voiding frequency, OSS, and QoL improved significantly. Bladder volume to first pain and maximal cystometric capacity more than doubled. Treatment remained effective in >50% of the patients for 9 mo. Retreatment was also effective in all cases, with similar duration. A significant, transient reduction in urinary NGF and BDNF was observed. No cases of voiding dysfunction occurred. The low number of patients and the lack of a placebo arm are obvious limitations of this study.

Trigonal injection of BoNTA is a safe and effective treatment for refractory BPS/IC.