Factors Affecting the Success of Intravesical Onabotulinum Toxin a Injection in the Treatment of Idiopathic Overactive Bladder

Abstract Purpose: Onabotulinum toxin A injection is an option recommended by the guidelines in the treatment of overactive bladder (OAB) that is resistant to medical treatments. Although success does not occur in every patient, the factors affecting success are not clearly known. The aim of this study is to evaluate the factors affecting the success of onabotulinum toxin A injection in the treatment of idiopathic OAB. Methods: Data of patients diagnosed with resistant idiopathic OAB and administered 100IU onabotulinum toxin A (BOTOX®, Allergan, Dublin, Ireland) between January 2019 and August 2023 were included in the study. Demographic data of the patients and duration of symptoms were recorded. The patients were followed up before the procedure and 1 month after the procedure using the overactive bladder symptom score (OABSS) inquiry form and 3-day bladder diaries. Patients who improved by 50% or more compared to the pre-procedure were considered satisfied with the treatment. Botox injection was applied to 20 points (5 IU per application) with a 22 Fr rigid cystoscope under sedoanesthesia in each patient. Results: A total of 210 patients were included in the study. 80.5% of patients were women (169/210). The average age of the patients was 53.76±14.90 (19-87). Symptom duration was 39.82±22.28 (6-120) months. A total of 175 patients were diagnosed with wet type OAB (83.3%) and 35 patients were diagnosed with dry type OAB (16.7%). The mean OABSS score of the patients before the procedure was 9.18±1.31 (6-13), the mean daily micturition was 8.67±1.52 (6-15), the mean urge urinary incontinence (UI) attack was 2.57±1.28, the average of nocturia was 1.87±0.75 (0-4), and the average number of pads per day was 2.44±1.24 (0-5). The success rate after onabotulinum toxin injection was 82.4% (173/210). Conclusion: The most important factors affecting the success of botulinum toxin A injection in the treatment of idiopathic OAB are affected by the high degree of complaint of the patient. Especially patients with high frequency of daily micturition complaints may not benefit from Botox treatment and may need advanced treatments.