Clinical and Urodynamic Results of Repeated Intradetrusor Onabotulinum Toxin A Injections in Refractory Neurogenic Detrusor Overactivity: Up to 5 Injections in a Cohort of Children With Myelodysplasia

Intravesical Botulin Toxin-A Injections for Neurogenic Bladder Dysfunction in Children: Summary Update on Last 10 Years of Research

Neurogenic bladder dysfunction (NB) represents a challenge in pediatric urology. Intravesical botulin toxin-A (BTX-A) bladder injection is part of the armamentarium for the treatment of this condition, usually after failed first-line medical strategies and before the escalation to more invasive options such as neuromodulation or augmented cystoplasty in severe cases. However, there is still a lack of consensus about the appropriate treatment modality for the pediatric population. A review of the last 10 years' research was performed on the PubMed database by two authors. Articles doubly selected and meeting the inclusion criteria were collected and analyzed for their study type, demographics, neurological disease(s) at diagnosis, BTX-A treatment modality and duration, previous treatment, clinical and urodynamic parameters, adverse events, outcomes, and follow-ups. A total of 285 studies were initially selected, 16 of which matched the inclusion criteria. A cohort of 630 patients was treated with BTX-A at a median age of 9.7 years, 40% of which had a diagnosis of myelomeningocele. The results of the selected publications show the overall efficacy and safety of BTX-A injections in children and confirmed BTX-A as a valuable strategy for NB treatment in pediatric population. Nevertheless, up to now, the literature on this topic offers scarce uniformity among the published series and poor protocol standardization.

An evaluation of onobotulinumtoxinA as a therapeutic option for pediatric neurogenic detrusor overactivity

INTRODUCTION

Neurogenic detrusor overactivity (NDO) results in involuntary detrusor contractions during bladder filling or storage risking transmission of pressure to the upper urinary tracts and/or significant incontinence. The goals of bladder management in children with NDO prioritize the preservation of renal function, prevention of UTIs, and optimizing quality of life. First-line measures include intermittent catheterization and anticholinergic medication. However, when conservative measures fail, surgical intervention may be indicated. Historically, the next step was major reconstructive surgery to create a low-pressure urinary reservoir. The introduction of intravesical botulinum neurotoxin A (BoNT/A) for use in children in 2002 offered a less invasive option for management. However, its exact role is still evolving.

AREAS COVERED

This article summarizes the mechanism of action of BoNT/A for management of NDO and evaluates the current literature defining common practice and clinical efficacy in children with NDO. The findings of the recently completed phase III trial for intravesical onabotulinumtoxinA in children are discussed in detail.

EXPERT OPINION

As the first BoNT/A approved for use in children with NDO, onabotulinumtoxinA appears to be a safe and less invasive alternative to major reconstructive surgery. However, data defining appropriate patient selection and its role as a long-term treatment option continue to develop.

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.

Repeated detrusor injection of botulinum toxin A for neurogenic bladder in children: A long term option?

AIMS

Evaluation of repeated (at least 4) intra-detrusor injections of toxin botulinum A (IDI-TBA) for neurogenic bladder in a pediatric cohort.

METHODS

Patients who underwent at least 4 IDI-TBA between 2005 and 2017 for neurogenic bladder related issues were included (detrusor overactivity and low compliance). Clinical and cystometric data were collected before and after the first injection and after the last injection. The primary endpoint was the proportion of patients with non-abnormal cystometry (no detrusor overactivity and normal compliance). Secondary outcomes were the evolution of the observed bladder capacity/expected ratio, surgical complications and acquired kidney impairment.

RESULTS

From the 832 patients referred to our institution for neurogenic bladder, 48 underwent IDI-TBA, and 17 at least 4 injections. Among them, a total of 95 procedures were performed (median per patient 5 [4-8]). While the first injection had a significant effect for 82.3% patients, the last injection improved the medical condition for only 53.0% cases. The bladder capacity ratio, initially 36.1%, increased to 80.3% after the first injection but decreased to a level of 57.1% at last. After a median follow-up of 57 [34-102] months, no severe complications were reported but 11.8% of patients presented with repeated pyelonephritis. A bladder augmentation surgery was finally indicated for 35.3% cases.

CONCLUSIONS

Despite a low complication rate and impressive cystometric results after the first injection, IDI-TBA efficacy decreased with time and repetition. These findings prone a long-term follow-up and a "à-la-carte" management of this specific population depending on the long-term response to IDI-TBA.

LEVEL OF EVIDENCE

2.

Botulinum Toxin Injection for Medically Refractory Neurogenic Bladder in Children: A Systematic Review

The objective was to evaluate the use of botulinum toxin A (BTX-A) injection in children with medically refractory neurogenic bladder. A systematic review of the literature was conducted using three databases (Medline via PubMed, Cochrane, and EMBASE). Articles evaluating BTX-A in children with neurogenic bladder were collected. The clinical and urodynamic parameters were reviewed for the safety and efficacy evaluation. Sixteen studies were selected into this study and a total of 455 children with medical refractory neurogenic bladder were evaluated. All of the patients had received traditional conservative medications such as antimuscarinics and intermittent catheterization as previous treatment. The duration of treatments ranged from 2 months to 5.7 years. Improvements in incontinence and vesicoureteral reflux were the most common clinical outcomes. The detrusor pressure, bladder capacity and bladder compliance improvement were the most common urodynamic parameters which had been reported. However, patient satisfaction with the procedure remained controversial. There was only a minimal risk of minor adverse effects. In all of the studies, BTX-A injection was well tolerated. In conclusion, BTX-A injection appears to be a safe and effective treatment in the management of medically unresponsive neurogenic bladder in children. There is currently no evidence that the use of BTX-A injection could be used as a first-line therapy for neurogenic bladder in children.

Beyond botulinum neurotoxin A for chemodenervation of the bladder

PURPOSE OF REVIEW

Botulinum neurotoxin A (BoNT/A), or Botox, is a popular option for overactive bladder (OAB) and neurogenic bladder (NGB) with or without incontinence. This review aims to discuss the clinical outcomes of BoNT in adult and pediatric bladder conditions, and introduces the potential benefit of novel, engineered neurotoxins beyond BoNT/A.

RECENT FINDINGS

A large volume of evidence supports the use of Botox for OAB (to reduce urgency, frequency and incontinence episodes), and for NGB (to decrease incontinence and improve bladder capacity and detrusor pressures). Botox is now also Food & Drug Administration (FDA)-approved for pediatric neurogenic detrusor overactivity. However, urinary retention, diminished response over time and treatment failures are prevalent issues with Botox. Modifying natural BoNTs or forming chimeric toxins are alternatives to BoNT/A that may have higher efficacy and lower side-effect profile. One example is BoNT/BMY-WW. This novel engineered toxin binds to a more commonly expressed synaptotagmin receptor, with potentially more potent paralytic effect and less capacity for systemic diffusion.

SUMMARY

Novel engineered neurotoxins may be the next frontier in OAB and NGB therapy.

Botulinum toxin therapy in children with neurogenic detrusor overactivity

Special birth defects and neurological diseases can cause neurogenic detrusor overactivity (NDO). First-line pharmacotherapy is the antimuscarinic therapy, which can be limited by side effects or non-effectiveness. Therefore, pharmacological treatment of NDO in children includes off-label use of intravesical injections of botulinum toxin type A (BTA). In this review article, various clinical studies in which BTA was used for the treatment of NDO of different etiologies in children are discussed, including studies about children with acquired NDO. An electronic literature search was performed using PubMed, and studies published prior to March 2019 are reported. BTA injections are a clinically and urodynamically effective and safe treatment for NDO in children. The treatment is also important in protecting the upper urinary tract from damage and improving concomitant bowel dysfunctions. Fibrotic, acontractile bladders with poor bladder compliance and/or a very small initial bladder capacity and/or the presence of an open bladder neck all contributed to poor responses. A combined injection into the detrusor and external urethral sphincter may improve the clinical outcome in the detrusor-sphincter dyssynergia. New application methods are promising, such as the electromotive drug administration, to avoid general anesthesia. Furthermore, the minimal clinically effective dosage, inclusion criteria, and prognostic factors remain to be established.

Medical Management of Neurogenic Bladder for Children and Adults: A Review

Neurogenic bladder is a chronic condition affecting patients of all ages with significant medical and quality of life implications. Goals of treatment consist of protection of the upper urinary tract and promotion of reliable urinary continence. Successful management involves medications and most often bladder drainage via clean intermittent catheterization. This article reviews current literature on medical management to achieve goals of treatment.