Overactive bladder (OAB) is the name for a group of urinary symptoms. It is not a disease. The most common symptom is a sudden, uncontrolled need or urge to urinate (1). The physiologic basis of these symptoms is detrusor overactivity (DO), defined as spontaneous or provoked involuntary detrusor contractions. Possible side effects may include generalized weakness, dysphagia, diplopia, and blurred vision(2).
In this retrospective analysis, we aimed to evaluate the effect of intravesical botulinum toxin injection on the symptoms in patients with idiopathic overactive bladder (iOAB) with no response to medical therapy

In this single-center retrospective analysis, all patients with refractory iOAB who had urodynamic study treated with Onabotulinum toxin A (100UI) (Botox)  were included. The linguistically validated Turkish version of OAB-V8 questionnaire and urodynamic study  were completed in all patients who had refractory iOAB before Botox injection to the bladder.  İOAB patients were divided into two groups including patients with overactive detrusor and patients without overactive detrusor with respect to urodynamic study. Patients were re-evaluated with OAB-V8 questionnaire at 12 weeks after Botox injection. Mann-Whitney U, Wilcoxon Signed Rank and Chi-square tests were used in statistical analyses. A p-value<0.05 was considered statistically significant.

Eighty four patients (55 women and 31 men) were included. Mean age was 48.9 years. The mean score of OAB-V8 was 13.52 (0-37) after  Botox injection while it was 28.9 (2-45) before Botox injection. There was no difference between men and women for OAB score regarding Botox injection (OAB score in men; 26.97 to 15.42, OAB score in women ; 30.06 to 12.42). However, the decrease of OAB-V8 symptom score after Botox injection in women with overactive detrusor (OAD) was statistically significant compared to men with overactive detrusor (72% vs 38%, p<0.05). On the other hand, there was no difference for the result of Botox injection between patients with OAD and patients without OAD. No difference was observed for the effect of urodynamic parameters on OAB score regarding the response of Botox injection.

The treatment of Botulinum toxin injection for OAB is well known therapy for a while. However, the effect of urodynamics on the outcome of intradetrusor Botox injections is not clarified in patients with symptoms of İOAB. In this study, the decrease of OAB symptom score was significantly better in women with OAD  than men with OAD. Hormonal factors or any other things could be a reason for this result that needs to be clarified in future studies

Botulinum toxin significantly decreased OAB-V8 symptom score in patients with İOAB. The response rate of Botox treatment in women with OAD is much better than in men with OAD. Urodynamic parameters was not significantly correlated with OAB symptom score related to Botox treatment. However, to have a comment regarding  the effect of urodynamic parameters on OAB symptom score  is controversial as regards limited number of this study.

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