Botulinum toxin in paediatric urology: a systematic literature review

Response to Treatment with Botulinum Neurotoxin A (BoNT-A) in Children and Adolescents with Neurogenic Lower Urinary Tract Dysfunction and Idiopathic Overactive Bladder: A Systematic Review and Meta-Analysis

INTRODUCTION

Botulinum neurotoxin A (BoNT-A) is a treatment option for neurogenic lower urinary tract dysfunctions (NLUTD) and idiopathic overactive bladder (OAB) in adults. Recently, its use has gained popularity in paediatric urology. Transitional urology deals with adolescents affected by congenital urological issues, who mature into adulthood. The aim of this systematic review was to update the current knowledge on the use of BoNT-A in children and adolescents.

METHODS

A comprehensive search in PubMed, Scopus, and Web of Science databases was performed from articles published up to September 2024. Both prospective and retrospective single-cohort or comparative studies evaluating outcomes of interest were included. These consisted of the amelioration of urinary incontinence (UI), continence rates, improvement of urodynamic parameters (maximum detrusor pressure during voiding, maximum bladder capacity, and bladder compliance), and type and prevalence of adverse/side effects. Qualitative and quantitative data syntheses were provided. Moderators and meta-regression analyses were carried out as well.

RESULTS

Forty-one full-text manuscripts were selected of which 26 focused on children with NLUTD, 13 on idiopathic OAB, and two on both conditions. Overall, 1521 patients were included of whom 715 were male, 646 female, and 160 of unknown sex. Mean age varied between 5.6 and 15.6 years. No studies specifically focused on transitional urology, despite patients up to at least 17 years of age being included. Several differences existed in design, type, dose, way of administration, outcomes measured and follow-up time; however, all studies independently showed an improvement of UI and urodynamic parameters with no major side/adverse events. Pooled analysis showed a mean rate of improvement in UI scores/episodes of 75.87% within a period of 3-6 months following BoNT-A treatment. Meta-regression analyses demonstrated a significant correlation between dryness rate and both patients' age (negative) and bladder compliance (positive).

CONCLUSIONS

Several uncontrolled or comparative studies provided significative evidence of the clinical benefit and safety of BoNT-A administration in children in terms of UI relief and improvement of urodynamic parameters, with neurogenic aetiologies being the most investigated conditions. A reduced bladder compliance was identified as one of the potential predictors of poor response to BoNT-A. Moreover, the earlier the treatment was started the higher the success rate that was reached in terms of dryness/urinary continence achievement.

Comprehensive overview of the available pharmacotherapy for the treatment of non-neurogenic overactive bladder in children

INTRODUCTION

Overactive bladder (OAB) is a chronic condition highly prevalent in children and causing bothersome symptoms. It is often associated with deterioration of quality of life and can be devastating for patients and their families. Prompt initiation of conservative measures should be the backbone of treatment. When conservative management fails, pharmacological options must be considered.

AREAS COVERED

Although antimuscarinics are considered the mainstay of pharmacological treatment for OAB, only two agents are currently approved for the pediatric population. Oxybutynin and propiverine are discussed in this review, as well as other non-approved antimuscarinic agents and β3-agonists with related literature to substantiate their use in children. Dual therapy along with medication adherence and persistence is also discussed.

EXPERT OPINION

The treatment of OAB in children is demanding and one must rely on a structured, stepwise approach to achieve success. Discussing conservative measures and prescribing medication is not enough. Clinicians should actively involve children and their families in the treatment, set realistic expectations, and closely monitor side effects and medication adherence to ensure maximal efficacy.

Onabotulinum toxin-A versus extended release tolterodine in the management of idiopathic overactive bladder in children: A pilot randomised controlled trial (OVERT trial)

BACKGROUND

Idiopathic Overactive Bladder is the most common cause of urinary incontinence in children. Anticholinergic medications are successful in only 20% of those with daily wetting so there is a real need to find a more effective treatment for this condition. Onabotulinum toxin A injections are often used as a treatment but there have been no randomised controlled trials investigating effectiveness in children.

OBJECTIVE

To provide information that would inform the design and conduct of a definitive trial comparing onabotulinum toxin A with extended-release tolterodine for the management of therapy resistant idiopathic overactive bladder in children. Specific objectives were to assess rates of eligibility, recruitment, acceptability of randomisation, loss to follow-up, acceptability of urodynamic assessment and obtain primary outcome data for sample size estimation.

STUDY DESIGN

Single-centre, parallel, two-arm, open-label pilot randomised controlled trial. Eligible patients (aged 7-16 years) were recruited at Royal Manchester Children's Hospital and randomised (1:1) using a web-based system.

TRIAL REGISTRATION

EudraCT 2014-001068-36; Funding: UK NIHR Research for Patient Benefit Programme.

RESULTS

98 patients were assessed for eligibility, 85 (87%) were eligible for screening, parents of 62 (73%) provided consent, 46 (74%) remained eligible and were randomised (onabotulinum = 22, tolterodine = 24). All participants commenced allocated treatment. Two patients withdrew from follow-up. All participants underwent urodynamic assessment at baseline and 35 (76%) additionally at week 6. The mean (standard deviation) number of wetting episodes per day at week 6 was 1.4 (1.7) in the onabotulinum group and 1.6 (1.0) in the tolterodine group. There was one serious adverse event (probably related to the drug) and 22 non-serious adverse events reported by 8 participants in the onabotulinum group (36%). There were 23 non-serious adverse events reported by 9 participants in the tolterodine group (38%).

DISCUSSION

Recruitment was challenging but eligibility and consent rates were high as were retention rates. Treatment compliance in the botox group was high but it was difficult to measure in the tolterodine group. Treatment switching was also an issue.

CONCLUSIONS

Recruitment to a definitive trial was demonstrated to be feasible if a large number of centres are involved, though further consideration is required regarding trial design.

Intravesical electromotive administration of botulinum toxin type A in improving the bladder and bowel functions: Evidence for novel mechanism of action

Objective: To examine the hypothesis that what is the concomitant mechanism of action botulinum toxin type A (BoNTA) administration by intravesical electromotive into the bladder resulting in bladder function improvement. We also tried to confirm the possibility of retrograde trans-axonal transportation of toxin.Design: Animal study.Setting: Ten male rabbits were divided into two groups.Participants: Group 1 (G1) (n = 5) (BoNTA/EMDA), and group 2 (G2) (n = 5) the control group.Interventions: Animals in G1received 10 IU/Kg of intravesical BoNTA through a specific catheter for electromotive drug administration (BoNTA/EMDA). About 0.1-0.15 ml of toxin was diluted in 1 ml of distilled water. The maximum frequency of the device for drug solution delivery was set at 4 mA for 15 min. In G2 as the control group, the same procedure was performed to deliver normal saline to the bladder.Outcome measures: Multiple biopsies were taken from bladder's contiguous structures one month postoperatively. The immunohistochemical (IHC) evaluation was performed with anti-clostridium botulinum toxoid type A mouse IgM monoclonal antibody.Results: In specimens of G1, BoNTA penetrated through muscular layers of the bladder wall and the staining was uniform in the urothelium, interstitium, and muscular layers. Positive IHC staining showed that BoNTA was traced in the upper and lower spinal cord in addition to pelvic nerve, sacral nerve plexus, intestine wall, and pelvic floor muscle. In G2, all the specimens were intact in IHC staining.Conclusions: The presence of BoNTA in lower and upper spinal cord suggests the possibility of retrograde trans-axonal transfer of toxin to lower and upper neural pathways which may result in simultaneous improvement in bladder and bowel functions.

Botulinum Toxin Type A Therapy: Intravesical Injection or Electromotive Drug Administration

OBJECTIVES

To compare the outcomes of intravesical injection of botulinum toxin A (BoNTA) with intravesical electromotive drug administration (EMDA) of BoNTA on urinary incontinence secondary to neuropathic detrusor overactivity (NDO) in children with myelomeningocele (MMC).

MATERIALS AND METHODS

A total of 26 children with MMC (11 boys, 15 girls) who had urinary incontinence secondary to NDO were retrospectively enrolled in the study. Patients in EMDA group (n = 14), using an electrode-catheter, 10 IU/kg of BoNTA were inserted into the bladder for EMDA without anesthesia and on an outpatient basis. The EMDA equipment was connected to the electrode of indwelling catheter and 2 dispersive electrodes, a pulsed current generator delivered 10-20 mA for 20 minutes. Patients in injection group (n = 12) were received interavesical injection of 10 IU/kg of BoNTA via rigid cystoscope on an inpatient basis. All patients had been evaluated by a voiding diary, urodynamic study, renal, and bladder ultrasounds before, 6 months and 1 year after the treatment.

RESULTS

Six months after the treatment, 12 of 14 (85.7 %) and 8 of 12 (66.6%) patients in EMDA and injection groups respectively became completely dry between 2 consecutive clean intermittent catheterizations, which maintained in 11 of 14 (78.5%) of patients in EMDA group compared to 6 of 12 (50%) of patients in injection group, 1 year after the treatment.

CONCLUSION

Patients in both groups improved after the treatment; however improvement in EMDA group was more prominent with better sustained effects. BoNTA/EMDA is a feasible, reproducible, cost benefit, and pain free method as an outpatient basis and no need for anesthesia.

The effects of antimuscarinic agents on the activity of the cardiac autonomic nervous system in children with functional overactive bladder

BACKGROUND

Functional overactive bladder disorder is one of the most prevalent presentations of bladder and bowel dysfunction in children, and it is associated with lower overall cardiac autonomic and parasympathetic activity. Antimuscarinics are the most frequently used pharmacological agents for treatment of children with functional overactive bladder disorder; however, there is a gap in the literature in describing the effect of antimuscarinics on the autonomic profile of this population.

OBJECTIVE

The aim of the study was to assess the cardiac parasympathetic activity before and after 12 weeks of oxybutynin treatment in children with overactive bladder.

METHODS

This was a single-institution prospective cohort study. Cardiac autonomic activity was assessed during storage and voiding phases of the bladder function via spectral analysis of heart rate variability and impedance cardiography. The primary outcome measure was high frequency, a proxy for parasympathetic nervous system activity. Parameters of uroflow study, severity of symptoms, and quality of life outcomes were also assessed.

RESULTS

Ten children (7 females) diagnosed with overactive bladder with a median age of 10 years (range = 6-14) were followed up for a median treatment duration of 11.8 weeks (range = 6-19.4). After treatment, there was a significant reduction in high frequency during the storage phase (median change = -24.17%, p = 0.047). No change was observed in the other outcome measures except for the overall Symptom Score for Dysfunctional Elimination Syndrome after treatment (5-point decrease, p = 0.034) (Summary Table).

DISCUSSION

The findings of the present follow-up study suggest that the use of oxybutynin in children with overactive bladder is associated with a significant reduction in the activity of the parasympathetic nervous system. The clinical implications of this finding are important because similar autonomic profiles (as markers of chronic stress) have been shown to be associated with increased inflammation and are found in major chronic diseases. The authors caution making a clinical connection between the heart rate variability profile of the patients in this study and patients with chronic diseases because oxybutynin is usually not administered as long-term treatment for overactive bladder.

CONCLUSION

Use of oxybutynin was associated with reduction in cardiac parasympathetic activity of children with functional overactive bladder. Further investigation into the role of the autonomic nervous system as a treatment target in the management of these children is warranted.

Intradetrusor injection of botulinum toxin A in children: a 10-year single centre experience

PURPOSE

We evaluated the efficacy and safety outcomes of endoscopic intradetrusor botulinum toxin A (BTA) injections for the treatment of children with neuropathic bladder (NB) and non-neuropathic bladder (NNB) with or without detrusor overactivity in a single centre with a retrospective analysis.

METHODS

For the period 2006-2015, children who received BTA in our hospital were analysed. They were divided into group 1, those with underlying NB and group 2, those without a clear neuropathic cause of symptoms (NNB). Data are given as percentages or medians (interquartile range).

RESULTS

Over the study period, 52 children (28 boys, 54%) received BTA, 28 in group 1 (54%; 17 (61%) boys) and 24 in group 2 (46%; 11 (46%) boys). Age at first injection was 11.8 (9.5-14.4) years. After initial injection, 40 (77%) reported symptomatic improvement, 17 (43%) becoming dry. There was no significant difference in response to initial injection between groups (p = 0.11). Duration of improvement after first injection was 7 (5.8-14) months. Twenty-five (48%) had further injections, of whom 3 (12%) were initial non-responders. Ongoing improvement was reported in 20 (80%), 11 (44%) of whom were dry. There was no significant difference in overall response to injections between groups (p = 0.11). Of the 11 non-responders, none (0/3) improved after subsequent injection and 3 (27%) subsequently underwent major urological surgery. Of the 40 who responded, 2 (5%) underwent major surgery.

CONCLUSION

BTA injection produced symptomatic improvement in 77% of our study population, with no significant differences in response between NB and NNB groups. In 95% of those who improved, major urinary tract procedures were avoided during the period studied. None of the initial non-responders improved after subsequent BTA injection. BTA injection is effective and reliable in the management of children with NB and NNB refractory to medical therapy.

Pyridostigmine for the Reversal of Severe Adverse Reactions to Botulinum Toxin in Children

Therapeutic botulinum toxin injections are commonly performed in pediatric otolaryngology. Aerodigestive complications from botulinum toxin injections, although rare, may be serious. Oral pyridostigmine is effective in the symptomatic treatment of these complications. We report 2 cases of aerodigestive complications arising from injection of botulinum toxin that were successfully treated with pyridostigmine.

Intravesical Electromotive Botulinum Toxin Type "A" Administration for Management of Urinary Incontinence Secondary to Neuropathic Detrusor Overactivity in Children: Long-term Follow-up

OBJECTIVE

To investigate the long-term efficacy and success rate of intravesical electromotive botulinum toxin type A (BoNTA) "Dysport" administration in patients with myelomeningocele who had urinary incontinence due to neuropathic detrusor overactivity (NDO).

MATERIALS AND METHODS

Twenty-four patients with myelomeningocele (mean age: 9 ± 3.6 years, range: 3-16) were included in the study and followed up for 6 years. Using an electrode bladder catheter, 10 IU/kg of Dysport (BoNTA) was inserted into the bladder for electromotive drug administration (EMDA) without anesthesia on outpatient basis. The EMDA equipment was connected to the electrode of an indwelling catheter and 2 dispersive electrodes, and a pulsed current generator delivered 10 mA for 20 minutes. The preliminary assessments were voiding diary, urodynamic study, kidney and bladder ultrasounds which were also performed annually.

RESULTS

Prior to the treatment, all patients had NDO and urinary incontinence. During the follow-up, 18 of 24 (75%), 11 of 24 (45.5%), 9 of 24 (37.5%), 8 of 24 (33%), and 7 of 24 (29.1%) of the patients were completely dry between 2 consecutive clean intermittent catheterizations after once BoNTA-EMDA treatment at 1, 2, 3, 5, and 6 years of follow-up, respectively. The mean maximum detrusor pressure significantly decreased and mean maximal cystometric capacity significantly increased at follow-ups (P <.05).

CONCLUSION

The results of the present study have shown that BoNTA-EMDA is a feasible, safe, reproducible, cost-effective, long-lasting, and pain free method on an outpatient basis, with long-term duration of effects without anesthesia or cystoscopy procedure. This novel delivery system resulted in considerable improvement in urinary incontinence and urodynamic study parameters in patients with refractory NDO.

Bladder and bowel dysfunction in children: An update on the diagnosis and treatment of a common, but underdiagnosed pediatric problem

Bladder and bowel dysfunction (BBD) describes a spectrum of lower urinary symptoms (LUTS) accompanied by fecal elimination issues that manifest primarily by constipation and/or encopresis. This increasingly common entity is a potential cause of significant physical and psychosocial burden for children and families. BBD is commonly associated with vesicoureteral reflux (VUR) and recurrent urinary tract infections (UTIs), which at its extreme may lead to renal scarring and kidney failure. Additionally, BBD is frequently seen in children diagnosed with behavioural and neuropsychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Patients with concomitant BBD and neuropsychiatric disorders have less favourable treatment outcomes. Early diagnosis and treatment of BBD are critical to avoid secondary comorbidities that can adversely impact children's kidney and bladder function, and psychosocial well-being. The majority of patients will improve with urotherapy, adequate fluid intake, and constipation treatment. Pharmacological treatment must only be considered if no improvement occurs after intensive adherence to at least six months of urotherapy ± biofeedback and constipation treatment. Anticholinergics remain the mainstay of medical treatment. Selective alpha-blockers appear to be effective for improving bladder emptying in children with non-neurogenic detrusor overactivity (DO), incontinence, recurrent UTIs, and increased post-void residual (PVR) urine volumes. Alpha-1 blockers can also be used in combination with anticholinergics when overactive bladder (OAB) coexists with functional bladder outlet obstruction. Minimally invasive treatment with onabotulinumtoxinA bladder injections, and recently neurostimulation, are promising alternatives for the management of BBD refractory to behavioural and pharmacological treatment. In this review, we discuss clinical presentation, diagnostic approach, and indications for behavioural, pharmacological, and surgical treatment of BBD in children based on a thorough literature review. Expert opinion will be used when scientific evidence is unavailable.

Recent Advances in Urinary Tract Reconstruction for Neuropathic Bladder in Children

Neuropathic bladder usually causes several limitations to patients’ quality of life, including urinary incontinence, recurrent urinary tract infections, and upper urinary tract damage. Its management has significantly changed over the last few years. The aim of our paper is to address some salient features of recent literature dealing with reconstructive procedures in pediatric and adolescent patients with lower urinary tract dysfunction.

The management of childhood urinary incontinence

The International Children's Continence Society (ICCS) has undertaken an enormous effort to standardize both the terminology and management of various aspects of incontinence in children, including enuresis, bladder overactivity, dysfunctional voiding and psychological comorbidities. A number of guidelines have been published to aid those involved in the care of children with lower urinary tract symptoms. This review addresses a number of recommended diagnostic and therapeutic strategies, including urotherapy and pharmacological treatment, with emphasis on a focused medical history, information acquired from bladder diaries and uroflow evaluations. The major role of urotherapy is underlined with supportive pharmacotherapy, when indicated. The article provides both a summary of ICCS guidelines and a brief review of recently published papers related to the contemporary management of childhood incontinence, a health issue still underestimated by both the child's caregivers and healthcare providers.

Effects of botulinum toxin type a in the bladder wall of children with neurogenic bladder dysfunction: a comparison of histological features before and after injections

PURPOSE

Botulinum toxin type A has gained popularity in urology. Most reported studies have been in adults at urology centers and most have addressed long-term safety. Since botulinum toxin type A treatment for neurogenic bladder dysfunction requires repeat injections, verifying that such treatment does not induce fibrosis in children seems essential.

MATERIALS AND METHODS

The study was approved by the institutional review board and patients were enrolled after we obtained written consent. Patients with neurogenic bladder dysfunction not responding to conventional treatment (anticholinergics and clean intermittent catheterization) were treated with 10 IU/kg botulinum toxin type A up to a maximum of 300 IU. Endoscopic cold cup biopsies were obtained from the posterolateral bladder wall 1.5 to 2 cm above the ureteral orifice. Bladder wall findings were categorized into 3 groups, including inflammatory infiltration, edema and fibrosis. Each criterion was then graded as mild or severe and analyzed by Fisher's exact test (p <0.05).

RESULTS

A total of 46 bladder wall biopsies were obtained from 40 patients 2 to 18 years old. Biopsies were evaluated in groups 1 and 2, including group 1-20 from patients with no botulinum toxin type A injection and group 2-20 after botulinum toxin type A injection. Group 2 was subdivided into group 3-10 biopsies after 1 injection and group 4-10 after multiple injections. Six patients underwent biopsy twice, that is before the first and second treatments. Histological changes were present in all biopsies. When comparing groups 1 and 2, there was no statistically significant difference in inflammation and edema. However, there was a significant difference in fibrosis between groups 1 and 4 (p <0.05) with apparently decreased fibrosis after multiple injections.

CONCLUSIONS

In our experience repeat botulinum toxin type A injections into the detrusor in children do not lead to increased fibrosis in the bladder wall. This study confirms the long-term safety of botulinum toxin type A in the pediatric population.

Intravesical electromotive botulinum toxin type A administration--part II: Clinical application

OBJECTIVES

To assess the effect of electromotive botulinum toxin type A administration on urodynamic variables, urinary/fecal incontinence, and vesicoureteral reflux (VUR) due to refractory neurogenic detrusor overactivity in children with myelomeningocele.

METHODS

A total of 15 children (mean age 7.8 years) were included. Using a specially designed catheter, 10 IU/kg of electromotive botulinum toxin type A was inserted into the distended bladder. While connected to the indwelling catheter and 2 dispersive pads, a pulsed current generator delivered 10 mA for 15 minutes. The urodynamic parameters, including reflex volume, maximal bladder capacity, maximal detrusor pressure, and end-fill pressure, and the urinary/fecal incontinence status and VUR grade were evaluated before and at 1, 4, and 9 months after treatment.

RESULTS

The mean reflex volume and maximal bladder capacity had increased considerably (99 ± 35 mL versus 216 ± 35 mL and 121 ± 39 mL versus 262 ± 41 mL, respectively; P < .001). In contrast, the mean maximal detrusor pressure and end-fill pressure had significantly decreased (75 ± 16 cm H(2)O versus 39 ± 10 cm H(2)O and 22 ± 7 cm H(2)O versus 13 ± 2 cm H(2)O) after treatment. The difference was statistically significant (P < .001). Urinary incontinence improved in 12 patients (80%). The VUR grade substantially decreased in 7 of the 12 children (mean VUR grade 2.25 ± 1.3 versus 1.37 ± 0.7; P = .001), and none of the children required surgical intervention. Fecal incontinence was alleviated in 10 (83.3%) of the 12 children. Skin erythema and burning sensation were observed in 6 children.

CONCLUSIONS

The results of our study have shown that electromotive botulinum toxin type A administration is a feasible and safe method with no need for anesthesia. This novel delivery system resulted in considerable improvement in the urodynamic parameters, urinary/fecal incontinence, and VUR in patients with refractory neurogenic detrusor overactivity.

Non-neurogenic elimination disorders in children

Non-neurogenic elimination disorders cover a wide spectrum of lower urinary tract and bowel dysfunctions, observed in the absence of a neurological background or lower urinary tract malformation. We reviewed conditions responsible for incontinence during bladder filling with normal voiding patterns (such as overactive bladder, giggle incontinence, post-void dribbling), and dysfunctional voiding syndromes. Dysfunctional elimination syndrome usually includes detrusor-sphincter dyscoordination, small-capacity overactive bladder or decompensated large poorly contractile bladder, and large-volume post-micturition residuals, occasionally associated with bowel dysfunction. At the most severe end of the spectrum lies the non-neurogenic neurogenic bladder syndrome, characterized by the association of a severe impairment of the upper urinary tract with a dysfunctional elimination syndrome. It must be emphasized that if the term 'non-neurogenic' relates to the absence of a neurological lesion, it is however conceivable that these conditions actually do have an underlying neurological cause that remains to be identified.