Does motor performance matter in botulinum toxin efficacy for drooling?

Predicting non-response to intraglandular botulinum neurotoxin A injections for drooling in children with neurodevelopmental disabilities

AIM

To develop robust multivariable prediction models for non-response to (1) submandibular botulinum neurotoxin A (BoNT-A) injections and (2) concurrent submandibular and parotid (four-gland) injections, to guide treatment decisions for drooling in children with neurodevelopmental disabilities, including cerebral palsy.

METHOD

This was a retrospective cohort study including 262 children (155 males/107 females, median age 7 years 11 months [IQR 5 years 1 month], range 4 years 0 months - 17 years 11 months) receiving submandibular injections and 74 children (52 males/22 females, median age 7 years 7 months [IQR 4 years 3 months], range 4 years 9 months - 18 years 8 months) receiving four-gland injections. Multivariable logistic regression analyses were used to estimate associations between candidate predictors and non-response 8 weeks after injection.

RESULTS

Ninety-six children (37%) were non-responders to submandibular injections, for which developmental age was the strongest predictor (adjusted odds ratio [aOR] 2.13; 95% confidence interval [CI] 1.02-4.45 for developmental age <4 years or 4-6 years with IQ <70). Other characteristics that showed a trend towards an increased risk of non-response were diagnosis, sex, and head position. Thirty-four children (46%) were non-responders to four-gland injections, for which tongue protrusion (aOR 3.10; 95% CI 1.14-8.43) seemed most predictive, whereas multiple preceding submandibular injections (aOR 0.34; 95% CI 0.10-1.16) showed a trend towards being protective. Predictors were, however, unstable across different definitions of non-response and both models (i.e. submandibular and four-gland) had insufficient discriminative ability.

INTERPRETATION

Potential predictors of non-response to BoNT-A injections were identified. Nevertheless, the developed prediction models seemed inadequate for guidance of treatment decisions.

WHAT THIS PAPER ADDS

Developmental age seemed most predictive of non-response to submandibular botulinum neurotoxin A injections. Non-response to concurrent submandibular and parotid injections was best predicted by tongue protrusion and number of previous injections. Multivariable prediction models including these clinical characteristics were unable to discriminate well. Predictors differed when non-response was defined using alternative outcome measures.

Comparing the evidence for botulinum neurotoxin injections in paediatric anterior drooling: a scoping review

Paediatric anterior drooling has a major impact on the daily lives of children and caregivers. Intraglandular botulinum neurotoxin type-A (BoNT-A) injections are considered an effective treatment to diminish drooling. However, there is no international consensus on which major salivary glands should be injected to obtain optimal treatment effect while minimizing the risk of side effects. This scoping review aimed to explore the evidence for submandibular BoNT-A injections and concurrent submandibular and parotid (i.e. four-gland) injections, respectively, and assess whether outcomes could be compared across studies to improve decision making regarding the optimal initial BoNT-A treatment approach for paediatric anterior drooling. PubMed, Embase, and Web of Science were searched to identify relevant studies (until October 1, 2023) on submandibular or four-gland BoNT-A injections for the treatment of anterior drooling in children with neurodevelopmental disabilities. Similarities and differences in treatment, patient, outcome, and follow-up characteristics were assessed. Twenty-eight papers were identified; 7 reporting on submandibular injections and 21 on four-gland injections. No major differences in treatment procedures or timing of follow-up were found. However, patient characteristics were poorly reported, there was great variety in outcome measurement, and the assessment of side effects was not clearly described.   Conclusion: This review highlights heterogeneity in outcome measures and patient population descriptors among studies on paediatric BoNT-A injections, limiting the ability to compare treatment effectiveness between submandibular and four-gland injections. These findings emphasize the need for more extensive and uniform reporting of patient characteristics and the implementation of a core outcome measurement set to allow for comparison of results between studies and facilitate the optimization of clinical practice guidelines. What is Known: • There is no international consensus on which salivary glands to initially inject with BoNT-A to treat paediatric drooling. What is New: • Concluding on the optimal initial BoNT-A treatment based on literature is currently infeasible. There is considerable heterogeneity in outcome measures used to quantify anterior drooling.and clinical characteristics of children treated with intraglandular BoNT-A are generally insufficiently reported. • Consensus-based sets of outcome measures and patient characteristics should be developed and implemented.

Botulinum Toxin A in the Management of Pediatric Sialorrhea: A Systematic Review

OBJECTIVE

Botulinum toxin A is known to be effective and safe in managing sialorrhea in pediatric patients; however, there is no consensus on a protocol for optimal injection sites and appropriate dosing for injection.

METHODS

This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol. PubMed, EMBASE, and other databases were queried to identify articles that evaluated botulinum toxin type A for the treatment of sialorrhea in the pediatric population. A total of 405 studies were identified. After applying inclusion and exclusion criteria, 31 articles were included for review.

RESULTS

A total of 14 studies evaluated 2-gland injections, and 17 studies evaluated 4-gland injections. Of the 31 studies included, one study assessed incobotulinumtoxinA (Xeomin®) the remaining all used onabotulinumtoxinA (Botox®). For 2-gland injection studies, a combined total of 899 participants were reviewed, where 602 participants received 50 units into their submandibular glands, while 262 participants received 30 to 50 units. Among 4-gland injection studies, there was a combined total of 388 participants, with the most prevalent dosage utilized being 60 to 100 units in 230 participants, followed by 100 units total in 77 participants. The most common adverse event was dysphagia which resolved in nearly all cases. Three studies aimed to examine 2-gland versus 4-gland injections, with 2 of the studies concluding 4-gland injection was superior.

CONCLUSIONS

The strength of evidence suggests that the dosing of 50 units total of onabotulinumtoxinA to the submandibular glands is safe and effective in the pediatric population. For 4-gland injections, bilateral submandibular and parotid gland injections of 60 to 100 units total is the safe and effective dosage. There is no substantial evidence comparing 4-gland injections to 2-gland injections, but research thus far suggests 4-gland injections to be superior. Future study is needed to evaluate incobotulinumtoxinA and abobotulinumtoxinA dosages in the pediatric population.

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

Background: We aimed to review and analyse the effectiveness and safety of botulinum toxin type A (BoNT-A) injections for drooling in children with cerebral palsy. Data sources: We searched the EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) databases from inception to January 2020. Methods: We included randomized controlled trials and observational studies which (1) involved children with cerebral palsy, (2) used BoNT-A for control of drooling, and (3) provided quantitative evaluations of drooling before and after intervention with BoNT-A. Results: Twenty-one trials met the inclusion criteria. Most studies showed that BoNT-A injections are safe and efficacious as a treatment for drooling in children with cerebral palsy. Four trials had sufficient data to pool the results for the meta-analysis. Both the drooling quotient (p = 0.002) and drooling Ffrequency and severity scale (p = 0.004) supported this conclusion. Conclusion: BoNT-A injections are a safe, reversible, effective treatment for drooling control in children with cerebral palsy that can offer effectiveness for more than 3 months with few side effects. The dosage of BoNT-A should not exceed 4 units/kg. Further studies are required to determine the optimal dosage and target glands.

A critical review of incobotulinumtoxinA in the treatment of chronic sialorrhea in pediatric patients

INTRODUCTION

Sialorrhea, also known as hypersalivation, ptyalis, or drooling, results in physical and psychosocial complications that may have a significant negative impact on quality of life for both the patient and their caregiver. The goal of pharmacological treatment is to reduce excessive salivary flow, while maintaining a moist and healthy oral cavity; until recently, however, few of the agents used to treat chronic sialorrhea have been approved in pediatric patients.

AREAS COVERED

This article summarizes early evidence for the use of botulinum neurotoxin A formulations in the treatment of children/adolescents with chronic sialorrhea, and findings of the recently completed phase III trial of incobotulinumtoxinA in this indication. Alternative therapies are also briefly discussed.

EXPERT OPINION

IncobotulinumtoxinA is the first botulinum neurotoxin A to be approved for the treatment of chronic sialorrhea in children and adults, following the results of phase III trials that demonstrate the efficacy and safety of the drug in these patients. The authors expect that the positive findings will result in updates to clinical guidelines for the treatment of children with chronic sialorrhea.

ABBREVIATIONS

AE, adverse event; AESI, adverse event of special interest; BoNT/A, botulinum neurotoxin A; CI, confidence interval; CP, cerebral palsy; DIS, drooling impact scale; DQ, drooling quotient; DSFS, Drooling Severity and Frequency Scale; GICS, Global Impression of Change Scale; LS, least squares; mTDS, modified Teacher's drooling scale; NR, not reported; PD, Parkinson's disease; SAE, serious adverse event; SE, standard error; SIAXI, Sialorrhea in Adults Xeomin Investigation; SIPEXI, Sialorrhea Pediatric Xeomin Investigation; SNAP-25, synaptosomal associated protein-25; TBI, traumatic brain injury; TDS, Teacher Drooling Scale; USA, United States of America; uSFR, unstimulated Salivary Flow Rate; VAS, visual analog scale.

Botulinum toxin injections for chronic sialorrhoea in children are effective regardless of the degree of neurological dysfunction: A single tertiary institution experience

OBJECTIVE

To determine the effectiveness of submandibular salivary gland Botulinum Toxin Type-A (BTX-A) injection in the treatment of drooling in children with varying degrees of neurological dysfunction.

METHODS

A retrospective review of pre- and post-procedure drooling frequency and severity scores of patients receiving BTX-A between January 2008 and January 2013. Stratification to different subgroups of neurological impairment was performed according to Gross Motor Function Classification System (GMFCS) score. Drooling severity was assessed using Thomas-Stonell and Greenberg symptom questionnaires administered at time of initial consultation and 3 months after treatment.

RESULTS

48 sets of BTX-A injections in 26 patients with an average age of 9.45 years (range 7 months-18 years) were included in the study. Marked improvement in drooling was seen in 60.4% of patients, a marginal or brief improvement was seen in 20.8% and there was no improvement in 18.8%. No adverse events were reported following any of the BTX-A injections. BTX-A was safe and effective in the eight patients with pre-existing swallowing dysfunction. Subsequent drooling surgery was performed in 15 (57.7%) of the cohort, all 15 patients responded to BTX-A injections. In patients with Cerebral Palsy, there was no correlation between the severity of the neurological dysfunction as measured by the Gross Motor Function Classification System (GMFCS) score and the response to BTX-A treatment.

CONCLUSIONS

Injection of BTX-A to the submandibular glands of children with neurological disorders is a safe procedure and results in a reduction in drooling in the majority of patients. Children with severe neurological dysfunction respond to BTX-A injections as effectively as their less impaired peers and the degree of response does not appear to be associated with the severity of neurological disability. BTX-A injection is a good initial procedure when drooling surgery is being considered.

Onabotulinumtoxin A Treatment of Drooling in Children with Cerebral Palsy: A Prospective, Longitudinal Open-Label Study

The aim of this prospective open-label study was to treat disabling drooling in children with cerebral palsy (CP) with onabotulinumtoxin A (A/Ona, Botox^®) into submandibular and parotid glands and find the lowest effective dosage and least invasive method. A/Ona was injected in 14 children, Mean age 9 years, SD 3 years, under ultrasonic guidance in six successive Series, with at least six months between injections. Doses and gland involvement increased from Series A to F (units (U) per submandibular/parotid gland: A, 10/0; B, 15/0; C, 20/0; D, 20/20; E, 30/20; and F, 30/30). The effect was assessed 2, 4, 8, 12, and 20 weeks after A/Ona (drooling problems (VAS), impact (0–7), treatment effect (0–5), unstimulated whole saliva (UWS) flow and composition)) and analyzed by two-way ANOVA. The effect was unchanged–moderate in A to moderate–marked in F. Changes in all parameters were significant in E and F, but with swallowing problems ≤5 weeks in 3 of 28 treatments. F had largest VAS and UWS reduction (64% and 49%). We recommend: Start with dose D A/Ona (both submandibular and parotid glands and a total of 80 U) and increase to E and eventually F (total 120 U) without sufficient response.

Relevance of intraglandular injections of Botulinum toxin for the treatment of sialorrhea in children with cerebral palsy: a review

BACKGROUND

After the age of 4 years, drooling becomes pathological and impacts the quality of life of children with cerebral palsy. Intraglandular injection of Botulinum toxin is one of the treatments available to limit this phenomenon.

AIMS

The objectives of this review were to validate the efficacy of Botulinum toxin injections for drooling in children with cerebral palsy, determine recommendations and identify potential side effects.

METHODS

We conducted a literature review from 2001 in the following databases: Embase, Pubmed and Cochrane using the keywords: sialorrhea, drooling, hypersalivation, Botulinum toxin, cerebral palsy and children. Only the articles evaluating the efficacy of Botulinum toxin in children with cerebral palsy over the age of 4 were researched.

RESULTS

Eight studies were found: 2 case studies, 3 open and non-controlled studies and 3 randomized controlled trials. Efficacy results in this indication are quite encouraging and the use of BTX injections is safe but the overall level of evidence of these studies was quite low.

CONCLUSION

However, intraglandular injection of Botulinum toxin has a place among the therapeutic array available for the management of sialorrhea in this population even if no standardized protocol is available yet.

Salivary gland botulinum toxin injections for drooling in children with cerebral palsy and neurodevelopmental disability: a systematic review

AIM

The aim of this paper was to systematically review the efficacy and safety of botulinum toxin (BoNT) injections to the salivary glands to treat drooling in children with cerebral palsy and neurodevelopmental disability.

METHOD

A systematic search of The Cochrane Central Register of Controlled Trials, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), EMBASE, and the Physiotherapy Evidence Database (PEDro) was conducted (up to 1 October 2011). Data sources included published randomized controlled trials (RCTs) and prospective studies.

RESULTS

Sixteen studies met inclusion criteria. Three outcome measures support the effectiveness of BoNT for drooling. One RCT found an almost 30% reduction in the impact of drooling on patients' lives, as measured by the Drooling Impact Scale (mean difference -27.45; 95% confidence interval [CI] -35.28 to -19.62). There were sufficient data to pool results on one outcome measure, the Drooling Frequency and Severity Scale, which supports this result (mean difference -2.71; 95% CI -4.82 to -0.60; p<0.001). There was a significant reduction in the observed number of bibs required per day. The incidence of adverse events ranged from 2 to 41%, but was inconsistently reported. One trial was terminated early because of adverse events.

INTERPRETATION

BoNT is an effective, temporary treatment for sialorrhoea in children with cerebral palsy. Benefits need to be weighed against the potential for serious adverse events. More studies are needed to address the safety of BoNT and to compare BoNT with other treatment options for drooling.