Botulinum A Toxin Treatment of Urethral Sphincter Pseudodyssynergia in Patients with Cerebrovascular Accidents or Intracranial Lesions

Outcomes of sequential third-line therapies in patients with refractory overactive bladder

INTRODUCTION

Sacral neuromodulation (SNM) and onabotulinumtoxinA (BoNTA) injection are third-line therapies for overactive bladder (OAB). Although the efficacy of each third-line treatment has been well established in clinical trials, there is far less information about performing one third-line therapy after the other. Our aim is thus to investigate the outcomes of post-SNM BoNTA and post-BoNTA SNM as "second" third-line treatments.

METHODS

We retrospectively reviewed all OAB patients who had both SNM and BoNTA between 2013 and 2022. The primary endpoint was the response rates (>50% improvements) of the second third-line treatments. Secondary endpoints were the proportion of the patients who achieved total dry, the duration of treatments of patients who had significant responses, and risk factors that are associated with treatment response or duration of treatments.

RESULTS

A total of 172 patients had two third-line therapies. There were 104 patients who had post-SNM BoNTA and 68 patients who had post-BoNTA SNM. In the post-SNM BoNTA group, 62.5% (65/104) had significant responses after BoNTA treatment. In the post-BoNTA SNM group, 61.8% (44/68) had significant responses after SNM treatment. The proportions of patients who became dry were 21.2% and 23.5%, respectively. In the post-SNM BoNTA group, spinal pathology is associated with a lower probability of a significant response (48.9% vs. 73.7%, p-value = 0.0105).

CONCLUSIONS

BoNTA or SNM remains a viable option for refractory OAB after patients fail from one another. Spinal pathology is associated with a poorer response of post-SNM BoNTA.

Role of Urological Botulinum Toxin-A Injection for Overactive Bladder and Voiding Dysfunction in Patients with Parkinson's Disease or Post-Stroke

Botulinum toxin A (BoNT-A) paralyzes muscle by blocking acetylcholine release at the synaptic junction. BoNT-A has shown its therapeutic effects in neurological disorders such as Parkinson's disease (PD) and post-stroke spasticity. A high proportion of patients with PD and post-stroke develop neurogenic detrusor overactivity (nDO) and then develop urinary incontinence and overactive bladder (OAB) symptoms. This study aimed to disclose the safety and efficacy of BoNT-A injection in treating bladder and voiding dysfunction in PD and post-stroke patients by reviewing the current evidence. At present, intradetrusor injection of BoNT-A is a Food and Drug Administration (FDA)-approved third-line therapy for nDO and idiopathic OAB. Although intradetrusor injection of onaBoNT-A 200 U is already approved for nDO treatment, most researchers would like to manage PD and post-stroke patients by using onaBoNT-A 100 U intradetrusor injection to achieve long-term efficacy and reduce adverse effects. However, in contrast to its inclusion in the International Continence Society guidelines for PD treatment, the clinical use of BoNT-A for post-stroke patients is limited to experimental use due to the development of urinary retention in about one-fifth of patients. For treating urethral pseudodyssynergia, half of patients may respond to onaBoNT-A 100 U urethral injection. However, refinement is needed to reduce unwanted urinary incontinence.

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.

Real-World Data Regarding Satisfaction to Botulinum Toxin A Injection into the Urethral Sphincter and Further Bladder Management for Voiding Dysfunction among Patients with Spinal Cord Injury and Voiding Dysfunction

Purpose: This study aimed to investigate improvement in voiding condition after the initial botulinum toxin A (BoNT-A) injection into the urethral sphincter among patients with chronic spinal cord injury (SCI) and voiding dysfunction. Moreover, subsequent surgical procedures and bladder management were evaluated. Materials and Methods: From 2011 to 2020, 118 patients with SCI and dysuria who wanted to void spontaneously received their first BoNT-A injection at a dose of 100 U into the urethral sphincter. Improvement in voiding and bladder conditions after BoNT-A treatment were assessed. Next, patients were encouraged to continually receive BoNT-A injections into the urethral sphincter, convert to other bladder managements, or undergo surgery. After undergoing bladder management and surgical procedures, the patients were requested to report improvement in voiding condition and overall satisfaction to bladder conditions. Then, data were compared. Results: In total, 94 male and 24 female participants were included in this analysis. Among them, 51 presented with cervical, 43 with thoracic, and 24 with lumbosacral SCI. After BoNT-A injections into the urethral sphincter, 71 (60.2%) patients, including 18 (15.3%) with excellent, and 53 (44.9%) with moderate improvement, had significant improvement in voiding condition. Patients with cervical SCI (66.6%), detrusor overactivity and detrusor sphincter dyssynergia (72.0%), partial hand function (80.0%), and incomplete SCI (68.4%) had a better improvement rate than the other subgroups. Only 42 (35.6%) patients continually received treatment with BoNT-A injections into the urethral sphincter. Meanwhile, more than 60% of patients who converted their treatment to augmentation enterocystoplasty (n = 5), bladder outlet surgery (n = 25), BoNT-A injections into the detrusor muscle (n = 20), and medical treatment (n = 55) had moderate and marked improvement in voiding dysfunction and overall satisfaction. Discussion: Although BoNT-A injections into the urethral sphincter could improve voiding condition, only patients with SCI who presented with voiding dysfunction were commonly satisfied. Those whose treatments were converted to other bladder managements, which can promote urinary continence, or to surgical procedures, which can facilitate spontaneous voiding, had favorable treatment outcomes.

Video-urodynamic characteristics of lower urinary tract dysfunctions in patients with chronic brain disorders

AIMS

Lower urinary tract dysfunction (LUTD) is common in patients with chronic brain disorders. This study investigated the video-urodynamic study (VUDS) findings of LUTD in patients with chronic brain disorders, including cerebrovascular accident (CVA), Parkinson's disease (PD), and early dementia.

METHODS

A total of 169 patients with a history of chronic brain disorders, including 84 with CVA, 55 with PD, and 30 with early dementia were enrolled. All patients had a comprehensive chart review, including brain disorder subtype, the period from diagnosis to VUDS, the VUDS parameters, and final LUTD.

RESULTS

The mean age of patients was 69.2 ± 10.5 years, and the interval from brain insult to VUDS was 61.3 ± 49.7 months. Urodynamic detrusor overactivity (DO) was noted in 73.4% of patients, detrusor underactivity in 10.1%, and detrusor overactivity with detrusor underactivity in 16.6%. Bladder outlet obstruction (BOO) was noted in 60.9% of patients, including bladder neck dysfunction in 21.3%, urethral sphincter dysfunction in 42%, and prostatic obstruction in 10.1% of male patients. Urethral sphincter dysfunction was noted in 60% of patients with PD, 32.1% with CVA, and 36.7% with dementia (p = 0.004). A low mean maximum flow rate increased post-void residual volume, and poor voiding efficiency was common in these patients, without significant differences among the subgroups.

CONCLUSIONS

Real-world VUDSs revealed that patients with chronic brain disorders not only had a high prevalence of DO but also impaired bladder contractility and a high rate of BOO at the level above the bladder neck and urethral sphincter.

Frontiers in the Clinical Applications of Botulinum Toxin A as Treatment for Neurogenic Lower Urinary Tract Dysfunction

Patients with neurogenic lower urinary tract dysfunction (NLUTD) experience urinary incontinence with or without difficult urination, which might promote recurrent urinary tract infection (UTI) and exacerbate upper urinary tract function. Nonetheless, appropriate bladder management has been shown to reduce urological complications and improve quality of life. In addition to pharmacological therapy and surgical intervention, botulinum toxin A (BoNT-A) has been widely utilized in NLUTD. The therapeutic efficacy of detrusor BoNT-A injections for neurogenic detrusor overactivity due to spinal cord injury (SCI), multiple sclerosis, or other central nervous system lesions, such as cerebrovascular accident, Parkinson disease, early dementia, and pediatric NLUTD due to myelomeningocele, has been well established, with repeated BoNT-A injections every 6 to 9 months being necessary to maintain its therapeutic effects. Urethral BoNT-A injection can decrease urethral sphincter resistance and facilitate efficient voiding in patients with NLUTD who wish to preserve self-voiding. Detrusor BoNT-A injection can also decrease the occurrence of autonomic dysreflexia in patients with SCI, even after failed augmentation enterocystoplasty, with additional benefits including reduced UTI episodes and preserved renal function with repeated injections. However, this treatment does have some side effects. Complete informed consent for BoNT-A injection therapy with full disclosure of its potential complications should therefore be obtained before this procedure is undertaken.

Therapeutic Effects of Botulinum Toxin A, via Urethral Sphincter Injection on Voiding Dysfunction Due to Different Bladder and Urethral Sphincter Dysfunctions

Botulinum toxin A (BoNT-A) urethral sphincter injections have been applied in treating voiding dysfunction but the treatment outcome is not consistent. This study analyzed treatment outcomes between patients with different bladder and urethral sphincter dysfunctions. Patients with refractory voiding dysfunction due to neurogenic or non-neurogenic etiology were treated with urethral sphincter 100 U BoNT-A injections. The treatment outcomes were assessed by a global response assessment one month after treatment. The bladder neck opening and urodynamic parameters in preoperative videourodynamic study were compared between successful and failed treatment groups. A total of 80 non-neurogenic and 75 neurogenic patients were included. A successful outcome was noted in 92 (59.4%) patients and a failed outcome in 63 (40.6%). The treatment outcome was not affected by the gender, voiding dysfunction subtype, bladder dysfunction, or sphincter dysfunction subtypes. Except an open bladder neck and higher maximum flow rate, no significant difference was noted in the other variables between groups. Non-neurogenic patients with successful outcomes had a significantly higher detrusor pressure, and patients with neurogenic voiding dysfunction with successful results had higher maximum flow rates and smaller post-void residuals than those who failed the treatment. However, increased urinary incontinence was reported in 12 (13%) patients. BoNT-A urethral sphincter injection is effective in about 60% of either neurogenic or non-neurogenic patients with voiding dysfunction. An open bladder neck during voiding and a higher maximum flow rate indicate a successful treatment outcome.

Therapeutic effect of urethral sphincter onabotulinumtoxinA injection for urethral sphincter hyperactivity

PURPOSE

Urethral sphincter hyperactivity resulting in voiding dysfunction is frequently encountered. Medical treatment might not achieve a satisfactory result. OnabotlinumtoxinA urethral sphincter injection relaxes sphincter tonicity and possibly resumes efficient voiding. This study analyzed the treatment outcomes and predictor for successful onabotulinumtoxinA treatment on these patients.

METHODS

Patients with voiding dysfunction due to urethral sphincter hyperactivity and treated with injections of 100 U onabotulinumtoxinA into the urethral sphincter were retrospectively reviewed. Treatment outcomes were assessed 1 month after injection using the Global Response Assessment and were analyzed by demographic and baseline video-urodynamic characteristics.

RESULTS

Of the 95 patients included, satisfactory outcomes were reported in 58 (61.1%) patients. Treatment outcome was not related to age, gender, or voiding dysfunction subtype. Patients with satisfactory outcomes had a significantly smaller volume at first sensation of filling (P = 0.046), greater detrusor pressure (P = 0.027), higher maximum flow rate (P = 0.017), and smaller post-void residual (P = 0.006). In multivariate analysis, an open bladder neck during voiding was the only predictor for successful outcome (88% in satisfactory outcome, 12% in failure outcome, P < 0.001). Patients with non-neurogenic voiding dysfunction had a significantly longer therapeutic duration than those with neurogenic voiding dysfunction (9.55 ± 4.18 vs 7.44 ± 2.91 months, P = 0.033). Increased urinary incontinence was reported in 18 patients, including 6 with stress urinary incontinence and 12 with urgency urinary incontinence.

CONCLUSION

Subjective improvement was reported in 61.1% of patients with voiding dysfunction due to urethral sphincter hyperactivity after onabotulinumtoxinA urethral sphincter injection. An open bladder neck during voiding at baseline predicts a successful outcome.

Botulinun A toxin urethral sphincter injection for neurogenic or nonneurogenic voiding dysfunction

Voiding dysfunction due to detrusor underactivity or urethral sphincter dysfunction is a treatment challenge for urologists. Recently, urologists have used botulinum toxin A (BoNT-A) injection into the urethral sphincter to treat voiding dysfunction. This treatment has been found to decrease urethral pressure and postvoid residual volume, and increase voiding efficiency in patients with neurogenic detrusor sphincter dyssynergia, nonneurogenic dysfunctional voiding, and detrusor underactivity. Although not all patients can achieve excellent therapeutic outcomes, patients with idiopathic detrusor underactivity might have recovery of detrusor contractility after urethral sphincter BoNT-A injection. However, urinary incontinence might be a de novo adverse event after treatment. Repeat urethral injection is necessary to maintain therapeutic efficacy. Patients should be fully informed of the limited therapeutic efficacy and possible adverse events prior to treatment. This article reviews recent studies of urethral sphincter BoNT-A treatment for voiding dysfunction.

Current and potential urological applications of botulinum toxin A

Botulinum toxin subtype A (BoNT-A) is a potent neurotoxin that can selectively modulate neurotransmitter release from nerve endings, resulting in muscular paralysis. BoNT-A might also act on sensory nerves, and have an anti-inflammatory effect. In the first urological use of BoNT-A, injection into the urethral sphincters of patients with detrusor-sphincter dyssynergia resulted in a reduction of urethral resistance and improved voiding efficiency. Subsequently, intravesical BoNT-A injections have received regulatory approval for treatment of neurogenic detrusor overactivity owing to spinal cord lesions or multiple sclerosis, and idiopathic overactive bladder in adults. BoNT-A has also been widely used to treat patients with the off-label indications of neurogenic or non-neurogenic voiding dysfunction and male lower urinary tract symptoms owing to BPH and bladder-neck dysfunction. Other indications for which urologists have applied BoNT-A injections include interstitial cystitis/bladder pain syndrome, bladder oversensitivity and chronic pelvic pain syndrome. BoNT-A is currently delivered as an intravesical injection; however, use of liposome encapsulated formulations is also beginning to show some therapeutic potential.

Botulinum toxin injection for lower urinary tract dysfunction

Botulinum toxin has been recently accepted as a novel treatment for lower urinary tract dysfunctions refractory to conventional treatment. Review of the clinical trials in recent years, botulinum toxin type A has been widely used in the urethra or urinary bladder to treat voiding dysfunction due to detrusor sphincter dyssynergia, incontinence due to neurogenic or idiopathic detrusor overactivity, sensory disorders such as bladder hypersensitivity, overactive bladder, and interstitial cystitis/painful bladder syndrome. Intravesical botulinum toxin type A injection is effective in treatment of urinary incontinence due to detrusor overactivity in men and women, as well as in children. Currently botulinum toxin type A has also been applied to treat lower urinary tract symptoms due to benign prostatic hyperplasia in patients not suitable for surgery. This article reviewed the recent advances of botulinum toxin type A on lower urinary tract dysfunction.

Hitting below the belt (Bladder): Botulinum treatment of urethral and prostate disorders

Botulinum toxin type A (BTX-A) has been used to treat urethral and prostatic diseases (off-label uses). Injection of BTX-A into the external sphincter of patients with detrusor external sphincter dyssynergia has been shown to successfully lower postvoid residual volumes and detrusor pressures. Average efficacy is 3 to 4 months, but long-term effects on detrusor leak point pressures or renal function are unknown. Injection of BTX-A into the prostate has shown promising short-term results (< or = 12 months) in improving the symptoms, postvoid residual volumes, maximal urinary flow rates, and prostate sizes in patients with benign prostatic hyperplasia. The mechanisms of action and long-term durability of this treatment modality are unknown. Evidence supporting the use of BTX-A in treating detrusor hypocontractility, pelvic floor dysfunction, postpubovaginal sling retention, urethral stricture, prostatitis, and chronic pelvic pain syndrome in men is preliminary and deserves further evaluation.

Recovery of Detrusor Function After Urethral Botulinum A Toxin Injection in Patients with Idiopathic Low Detrusor Contractility and Voiding Dysfunction

OBJECTIVES

To investigate the effect of urethral botulinum A toxin (BoNT-A) injection on idiopathic low detrusor contractility and the correlation of this effect with baseline urodynamic parameters.

METHODS

Twenty-seven patients with idiopathic low detrusor contractility received urethral injection of BoNT-A. Videourodynamic studies were performed at baseline and after treatment. Recovery of detrusor contractility was defined as an increase in detrusor pressure and maximal flow rate and reduced postvoid residual urine volume. The therapeutic results and changes in urodynamic parameters were compared between patients with and without recovery of detrusor contractility.

RESULTS

The recovery of detrusor contractility after urethral BoNT-A injection occurred in 13 patients (48%). Patients with recovery of detrusor contractility had baseline data characterized by normal bladder sensation during bladder filling combined with a poor relaxation or hyperactive urethral sphincter activity. In contrast, patients without recovery of detrusor contractility had poor bladder sensation and a nonrelaxing urethral sphincter. Patients with baseline characteristics of low detrusor contractility combined with poorly relaxed or hyperactive urethral sphincter activity had better results than those with true detrusor underactivity. Of the 13 patients with recovery of detrusor contractility, 5 had a long-term therapeutic effect without the need of repeat urethral injection of BoNT-A for more than 1 year of follow-up.

CONCLUSIONS

Patients with detrusor underactivity with normal bladder sensation combined with a poor relaxation or hyperactive urethral sphincter were significantly more likely to recover normal detrusor function. Neuromodulation of the hyperactive urethral sphincter by urethral BoNT-A is the likely mechanism for this therapeutic effect.