Owing to the diverse treatment outcomes after a botulinum toxin A (BoNT-A) injection to the external sphincter, this study aimed to develop a new technique: an ultrasound-guided BoNT-A external sphincter injection. This single-center prospective cohort study was conducted at a tertiary medical center in Taichung, Taiwan. From December 2020 to September 2022, 12 women were enrolled. The patients were evaluated for lower urinary tract syndrome using patient perception of bladder condition (PPBC), international prostate symptom score (IPSS), uroflowmetry, post-void residual volume (PVR), cystometry, and external sphincter electromyography. We evaluated the patients the day before surgery and 1 week after the BoNT-A injection. For the patients requiring self-catheterization, we recorded the number of times they required clean intermittent catheterization (CIC) per day before the procedure and 1 month after the procedure. The IPSS, PPBC, and PVR were significantly better after the transvaginal ultrasound-guided BoNT-A external sphincter injection. The number of times the patients required daily CIC was also reduced after the injection. Only one patient developed de novo urge urinary incontinence. Our results demonstrated that a transvaginal ultrasound-guided BoNT-A injection was efficacious and safe in the treatment of underactive bladder.

Background: Treating an underactive bladder (UAB) is challenging. Previously, we introduced a more precise method of transvaginal ultrasound-guided botulinum toxin A (BoNT-A) injection into the external urethral sphincter as a treatment option for patients with UABs. Although many patients experience good results, those with an UAB and excessive residual urine still require catheterization. Therefore, we developed a new method that combines transvaginal ultrasound-guided BoNT-A injection with a transurethral bladder neck incision. Methods: A prospective study was conducted on 16 patients who experienced symptoms of UAB and chronic urine retention. The treatment consisted of a combination of transvaginal ultrasound-guided BoNT-A injection and a transurethral incision of the bladder neck (TUI-BN). The primary objective was to assess the efficacy of this combined treatment in improving symptoms in women with UABs. Results: Our study demonstrated significant improvements after treatment, including increased voiding volume, decreased post-void residual (PVR) urine, and improved voiding efficiency. The frequency of clean intermittent catheterization (CIC) decreased at 1 and 3 months post-surgery, along with improvements in the AUA symptoms score and the Patient Perception of Bladder Condition (PPBC) score. Conclusions: Our study showed significant improvements in the surgical treatment of UABs using a combination of transvaginal ultrasound-guided BoNT-A and TUI-BN.