Botulinum Toxin Injections for Treatment of Drooling in Children with Cerebral Palsy: A Systematic Review and Meta-Analysis

Understanding Clinical Effectiveness and Safety Implications of Botulinum Toxin in Children: A Narrative Review of the Literature

Since its first approval by the Food and Drug Administration in 1989 for strabismus, botulinum toxin indications of use have been widely expanded. Due to its anticholinergic properties, this toxin is currently approved in adult patients for the treatment of a wide range of neuromuscular, otolaryngologic, orthopedic, gastrointestinal, and urologic disorders. Approved pediatric indications of use include the treatment of blepharospasm associated with dystonia, strabismus, lower-limb spasticity, focal spasticity in patients with cerebral palsy, and neurogenic detrusor overactivity. Alongside these approved indications, botulinum toxin is extensively used off-label. Although several clinical studies have shown that botulinum toxin is effective and well-tolerated in children, uncertainties persist regarding its long-term effects on growth and appropriate dosing in this population. As such, further research is needed to better define the botulinum toxin risk-benefit profile and expand approved uses in pediatrics. This narrative review aimed to provide a broad overview of the evidence concerning the clinical effectiveness and safety of BoNT with respect to its principal authorized and non-authorized pediatric therapeutic indications, as well as to describe perspectives on its future use in children.

A systematic review of the perspectives of botulinum toxin use on the quality of life of neurological patients with drooling

OBJECTIVE

To investigate the effectiveness of botulinum toxin in the salivary glands of patients with neurological impairment and drooling and its impact on the quality of life.

MATERIALS AND METHODS

This systematic review was registered with the International Prospective Register of Systematic Reviews (CRD 42,023,435,242) and conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. An electronic search was performed in the PubMed/MEDLINE, Embase, Scopus, Cochrane Library, and clinical trial databases until August 2023, no language restriction. Cohort studies and randomized clinical trials of patients diagnosed with drooling and neurological impairment who used botulinum toxin on the salivary gland were included, which evaluated subjective quality of life parameters. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist and Risk of Bias 2 tools. The certainty of the evidence was analyzed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Eight studies involving 317 patients were included. All studies, through subjective parameters, suggested the effectiveness of botulinum toxin in reducing drooling, resulting in an improvement in the quality of life. Three studies demonstrated improvements in swallowing and four in cases of respiratory diseases. Two clinical trials had a high risk of bias, whereas one had low risk. The five cohort studies that were evaluated had a high risk of bias. The certainty of the evidence was considered low.

CONCLUSIONS

Based on the patient/caregivers' perception of improvement in drooling, dysphagia, and respiratory symptoms, it can be inferred that botulinum toxin application reduces subjective drooling in neurologically compromised patients. Its impact contributes to the general well-being and quality of life.

CLINICAL RELEVANCE

Injection of botulinum toxin into the salivary glands can be considered an alternative technique to surgical or medicinal approaches in reducing drooling. It is effective, less invasive and without significant side effects. It promotes a positive impact on the well-being and quality of life of neurological patients.

Pharmacologic Management of Sialorrhea in Neonatal and Pediatric Patients

Sialorrhea, defined as an excess flow of saliva or excessive secretions, is common in patients with cerebral palsy and other neurologic disorders and is associated with clinical complications such as increased risk of local skin reactions, infections, aspiration, pneumonia, and dehydration. Upon failure of non-pharmacologic measures, clinicians have several noninvasive pharmacologic options available to manage sialorrhea. This review of the literature provides detailed descriptions of medications used, efficacy, safety, and practical considerations for use of non-injectable pharmacologic agents. The literature search included published -human studies in the English language in PubMed and Google Scholar from 1997 to 2022. Relevant citations within articles were also screened. A total of 15 studies representing 719 pediatric patients were included. Glycopyrrolate, atropine, scopolamine, and trihexyphenidyl all have a potential role for sialorrhea management in children; however, glycopyrrolate remains the most studied option with 374 (n = 52.0%) of the 719 patients included in the systematic review receiving this medication. Overall, glycopyrrolate showed similar efficacy but higher tolerability than its comparators in 2 comparative studies and is often considered the first-line agent. Patient-specific (age, route of administration) and medication-specific (dosage formulation, medication strength) considerations must be weighed when initiating a new therapy or switching to another medication upon treatment failure. Owing to the high propensity of adverse events with all agents, clinicians should consider initiating doses at the lower end of the dosage range, as previous studies have noted a dose-dependent relationship.

Botulinum Toxin for Drooling in Adults with Diseases of the Central Nervous System: A Meta-Analysis

(1) Background: The purpose of this study was to determine whether the drooling of adult patients with diverse central nervous system diseases can be treated with botulinum toxin type A. (2) Methods: The Cochrane Library, MEDLINE, and Embase were all searched for studies that fit the inclusion criteria. The patients in the studies had to be adults (>18 years old), and the studies had to be randomized placebo-controlled trials, controlled trials, or prospective studies. Each study had to have enough quantifiable data available for meta-analysis. The primary outcome measure was the Drooling Severity and Frequency Scale (DSFS). (3) Results: The meta-analysis comprised three studies. A statistically significant difference in DSFS score between the treatment and control groups was observed in the meta-analysis, with an overall standardized mean difference of -0.9377 (95% CI, -1.2919 to -0.5836; p < 0.0001). A total of seven studies were ineligible for inclusion in the meta-analysis and were only assessed as qualitative data. All qualitative studies showed a significant reduction in DSFS score a few weeks or months after the injection of botulinum toxin. (4) Conclusions: Botulinum toxin type A is safe and effective as a treatment for drooling in adult patients with central nervous system diseases.

Effectiveness of the pharmacological treatments for sialorrhea in patients with Parkinson's disease: a systematic review and network meta-analysis

OBJECTIVES

The present systematic review and network meta-analysis of randomized control trials (RCTs) aimed to establish whether there are evidence-based differences in the pharmacological agents used to manage sialorrhea in patients with Parkinson's disease (PD).

MATERIAL AND METHODS

The authors searched the databases: MEDLINE via PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library for clinical trials. Unpublished trials were searched on clinicaltrials.gov and the Brazilian Clinical Trials Registry. Means and standard deviations of changes in the salivary flow or drooling reported by participants due to the interventions were recorded.

RESULTS

The authors analyzed 13 RCTs. Compared to the placebo, types A and B of the botulinum toxin effectively reduced the salivary flow and the severity or frequency of drooling. However, the network meta-analysis did not differentiate between the botulinum toxin types. Ipratropium bromide and glycopyrrolate did not differ from the placebo. Indirect evidence showed that ipratropium had similar results to those obtained with both types of botulinum toxin. The CINeMA approach estimated the quality of the evidence as very low for all comparisons.

CONCLUSION

The best treatment for sialorrhea in patients with PD is not fully elucidated yet. Therefore, more well-conducted randomized clinical trials are required to increase the level of evidence.

CLINICAL RELEVANCE

There needs to be more evidence defining the best intervention to treat sialorrhea in patients with PD. However, botulinum toxin types A and B seem to reduce sialorrhea in patients effectively.

Pharmacological Interventions for Sialorrhoea in People with Parkinson's Disease: A Systematic Review and Meta-Analysis

Background/objectives

Sialorrhoea is a common non motor complication experienced by people with Parkinson's disease (PD). Despite its prevalence there is conflicting evidence on how to effectively treat it. Our aim was to establish the efficacy and safety outcomes of pharmacological interventions used to treat sialorrhoea in people with idiopathic PD.

Methods

We registered and conducted a systematic review and meta-analysis (PROSPERO: CRD42016042470). We searched seven electronic databases from inception until July 2022. Quantitative synthesis was performed where data allowed using random effects models.

Results

From 1374 records we included 13 studies (n = 405 participants). Studies were conducted in Europe, North America and China. There was marked heterogeneity in the interventions used, follow up times and outcome measures investigated. The main source of risk of bias identified was reporting bias. Five studies were included in the quantitative synthesis. Summary estimates showed administration of botulinum toxin significantly reduced saliva production, improved patient reported functional outcomes and was associated with an increase in adverse events.

Conclusion

Sialorrhoea in PD is an important condition, but current data does not allow for strong recommendations on optimal pharmacological treatments. There is significant heterogeneity in outcomes measures used to evaluate the burden of sialorrhoea with lack of consensus on what constitutes clinically meaningful change. More research is required to better understand the underlying mechanism and potential treatments of sialorrhoea in idiopathic PD.

Botulinum Toxin, a Drug with Potential Interest for Dentists—An Introduction

The review is an introduction to medical, non-cosmetic treatments with botulinum neurotoxin (BoNT) in the orofacial region. It focuses on the current most common, best-documented and safest indications of interest for dentists in terms of dystonia and sialorrhea. These conditions are recommended to start with and suitable to gain better skill and experience with BoNT. The introduction also stresses the importance of correct diagnostics based on interdisciplinary cooperation, precise targeting of the injections, measurements of treatment effect, and control of the oral health with regard to side effects.

Safety Profile and Lack of Immunogenicity of IncobotulinumtoxinA in Pediatric Spasticity and Sialorrhea: A Pooled Analysis

IncobotulinumtoxinA, a pure botulinumtoxinA formulation, is free of accessory proteins. This analysis provides pooled safety data from phase 3 trials of children/adolescents (2–17 years), investigating incobotulinumtoxinA for the treatment of spasticity associated with cerebral palsy (at doses ≤20 U/kg (max. 500 U) per injection cycle (IC) for ≤6 ICs; three trials) or sialorrhea associated with neurologic disorders (at total doses of 20–75 U per IC for ≤4 ICs; one trial) for ≤96 weeks. Safety endpoints included the incidences of different types of treatment-emergent adverse events (TEAEs) and immunogenicity. IncobotulinumtoxinA dose groups were combined. Of 1159 patients (mean age 7.3 years, 60.4% males) treated with incobotulinumtoxinA, 3.9% experienced treatment-related TEAEs, with the most common being injection site reactions (1.3%) (both indications), muscular weakness (0.7%) (spasticity), and dysphagia (0.2%) (sialorrhea). Two patients (0.2%) experienced a treatment-related treatment-emergent serious adverse event, and 0.3% discontinued the study due to treatment-related TEAEs. No botulinumtoxinA-naïve patients developed neutralizing antibodies (NAbs) after incobotulinumtoxinA. All children/adolescents with known pre-treatment status and testing positive for Nabs at final visit (n = 7) were previously treated with a botulinumtoxinA other than incobotulinumtoxinA. IncobotulinumtoxinA was shown to be safe, with very few treatment-related TEAEs in a large, diverse cohort of children/adolescents with chronic conditions requiring long-term treatment and was without new NAb formation in treatment-naïve patients.

Developing an intrasalivary gland botox service for patients receiving long-term non-invasive ventilation at home: a single-centre experience

Introduction

Sialorrhoea is a debilitating symptom in neurological disease and there is a growing literature for the use of intrasalivary gland Botulinum Toxin (botox) injections in its management. However, provision of intrasalivary gland botox remains inconsistent and sialorrhoea is often poorly controlled in motor neuron disease (MND).

Sialorrhoea in association with bulbar dysfunction can cause intolerance of non-invasive ventilation (NIV) and respiratory infection, so its treatment is critical within a home ventilation service (HVS).

This treatment can also be used to enable tracheostomy cuff deflation to facilitate weaning from ventilation. We report on the outcomes of intrasalivary gland botox in our HVS.

Methods

In 2015, we set up an intrasalivary gland botox service for patients under our HVS. Under ultrasound guidance, we injected submandibular gland

(SMG), parotid gland (PG) or both.

Results

109 intrasalivary gland botox procedures were performed in 72 patients. Diagnostic groups included MND 32

Cerebral Palsy 8 and Weaning 14. Glands injected were, SMG (6%), PG (47%) and both (47%). The majority (84%) received the Dysport preparation with mean dose 273 units. 94% were ultrasound guided. 81% of injections resulted in a positive treatment effect, with 47% patients requesting repeat injections. Complications were angioedema (0.9%) and worsening dysphagia (3.7% following SMG injection). Mean survival following treatment was 40 months with 53% patients still alive.

Conclusions

Intrasalivary gland botox appears effective across a range of neurological conditions requiring long-term NIV with few complications. Dysphagia may be an important complication of SMG injection. A randomised controlled trial may help establish the evidence base.