Efficacy and safety of botulinum toxin a injection into urethral sphincter for underactive bladder

Long-term Outcomes of Periurethral Sphincter Botulinum Toxin in Female Chronic Urinary Retention

PURPOSE

Nonneurogenic chronic urinary retention is an uncommon problem in young female individuals, and a well characterised causes is Fowler syndrome (primary disorder of urethral sphincter relaxation). Intermittent catheterisation is often challenging, and gold standard treatment sacral neuromodulation is not widely available. Urethral sphincter botulinum toxin injection has been shown to be effective cross-sectionally, however little is known about long-term outcomes.

METHODS

Female individuals presenting with urinary retention due to Fowler syndrome were reviewed retrospectively from a single tertiary referral centre over an 11-year period (2010-2021). One hundred units of onabotulinum toxin A (BoTX-A) was injected into the striated urethral sphincter in a divided dose by the periurethral approach. Efficacy and side effects were assessed 4 weeks after injection.

RESULTS

Thirty-three female individuals with a mean age of 40.1±14.1 years received 165 unique urethral sphincter BoTX-A injections over 11 years. Nineteen individuals (57.6%) presented in acute urinary retention, and 28 (84.8%) were reliant on catheterisation. Twenty-one individuals (64%) responded to BoTX-A injections and had a significantly raised baseline maximum urethral closure pressure (MUCP), compared to nonresponders (114.6 cm H2O, P=0.012). Side effects were reported following 19 injections (11.5%) however, were mild and transient. Fifteen individuals received more than 1 botulinum toxin injection (median, 3 injections), with a median interval of 112 days (interquartile range) and efficacy persisted following repeat injections and no safety concerns were seen.

CONCLUSION

Sphincter botulinum toxin through the periurethral approach is safe and effective following repeat injections, and offers a low-cost, minimally invasive alternative to managing female chronic urinary retention due to Fowler syndrome, particularly when there was a high baseline MUCP.

Biomimetic urine flow control can preserve bladder function in patients with indwelling catheterization

For patients with long-term indwelling catheterization, bladder function will be affected. It is necessary to explore whether biomimetic urine flow control (BUFC) can improve bladder function in patients undergoing indwelling catheterization. A retrospective, data-only, cohort study was carried out. The patients admitted to the intensive care unit, who had retained catheter and been continuously using a urodynamic monitoring system for over 30 days were selected. They were divided into 2 groups based on whether they were using BUFC function. The urodynamic monitoring data of the 2 groups were compared and analyzed. A total of 30 patients were included in the final analysis, including 15 in the BUFC group and 15 in the unobstructed group. The Urinary Volume and maximal urinary flow rate of the unobstructed group showed a continuous downward trend, while the BUFC group remained stable, and there was a statistical difference (P < .05) between the 2 groups since day 20. The bladder ultrasound imaging showed that the bladder volume of the BUFC group did not decrease significantly on the 30th day. BUFC technology, which provided by a urodynamic monitoring system, has potential protective effects of the bladder function after indwelling catheterization.

Botulinum Toxin Brings a Light to the Shadow of Functional Urology

Functional urology involves a large scale of lower urinary tract dysfunctions (LUTDs), including bladder dysfunctions and bladder outlet dysfunctions [...].

The Efficacy of Transvaginal Ultrasound-Guided BoNT-A External Sphincter Injection in Female Patients with Underactive Bladder

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.

Detrusor Underactivity in Men with Bladder Outlet Obstruction

Detrusor underactivity (DU) and bladder outlet obstruction (BOO) are both common troublesome causes of lower urinary tract symptoms (LUTS) and often impact on quality of life simultaneously in men. This article aims to focus on DU with BOO in male patients.

METHODS

Original articles concerning DU with BOO were identified through literature research from PubMed and EMBASE database. We selected 38 articles in our review, including those concerning pathophysiology, evaluation, treatment and predictors for a successful BOO surgery for DU.

RESULTS

DU from BOO can result from several pathophysiological mechanisms. Although urodynamic study (UDS) is considered as a precise method to diagnose DU and BOO, there are some previous studies which proposed a non-invasive method to identify DU related to BOO. The treatment goal of DU is restoring bladder contractility using medication or surgery. Releasing outlet obstruction and resistance is the main strategy to restore bladder contractility when medication to directly increase bladder contractility has had limited efficacy.

CONCLUSIONS

DU from BOO is poorly understood and is largely under-researched. The etiology and pathophysiology still need to be evaluated. Effective and safe medication to restore bladder contractility is also lacking. It remains valuable to perform further research to reveal the unknown aspects of DU.

Clinical Application of Botulinum Neurotoxin in Lower-Urinary-Tract Diseases and Dysfunctions: Where Are We Now and What More Can We Do?

Botulinum toxin A (Botox) had been considered a promising drug that has an effect on functional disorders of the lower urinary tract. Because Botox exhibits anti-inflammatory and antispasmodic effects, Botox injection into the bladder can decrease detrusor contractility, reduce bladder hypersensitivity, and eliminate painful sensations. Injecting Botox into the bladder outlet can relax the hyperactivity of the bladder neck, and of the urethral smooth and striated muscles. Based on these therapeutic effects, Botox has been widely applied to treat lower-urinary-tract dysfunctions (LUTDs) such as overactive bladder and neurogenic detrusor overactivity. However, this treatment has not been licensed for use in other LUTDs such as interstitial cystitis, voiding dysfunction due to benign prostatic hyperplasia in men, and dysfunctional voiding in women. Botox has also not been approved for the treatment of children with overactive bladder and dysfunctional voiding; in patients with spinal cord injuries with detrusor sphincter dyssynergia and autonomic dysreflexia; or for poorly relaxed external sphincter in non-neurogenic patients. This article reviews the current knowledge regarding Botox treatment for LUTDs and discusses the potential clinical applications of Botox, as well as work that can be conducted in the future.