Effect of recurrent onabotulinum toxin a injection into the salivary glands: An ultrasound measurement

Alteration of myoepithelial cells during botulinum toxin type A-inhibited salivary secretion

OBJECTIVE

Intraglandular injection of botulinum toxin type A (BoNT/A) effectively treats sialorrhea. Myoepithelial cells (MECs) are essential for salivary secretion. The role of MECs in BoNT/A-inhibited salivary secretion, and its underlying mechanisms remain unknown.

MATERIALS AND METHODS

BoNT/A was injected into rat submandibular glands (SMGs). At 1, 2, 4, 8, and 12 weeks postinjection, salivary flow rate of SMGs was measured. Electron microscopy, immunohistochemistry, immunofluorescence, and Western blot analysis were used to detect morphological and functional changes in MECs and chemical denervation in SMGs.

RESULTS

BoNT/A temporarily decreased salivary secretion in rat SMGs and this inhibitory effect lasted 4 weeks. During the inhibitory period, MECs atrophied and expressed reduced α-smooth muscle actin (α-SMA), vimentin, and phosphorylated myosin light chain 2 (p-MLC2), suggesting that BoNT/A attenuated MEC contractility. Furthermore, BoNT/A cleaved synaptosome-associated protein 25 (SNAP-25) and decreased the expression and activity of acetylcholinesterase (AChE), indicating that BoNT/A-induced chemical parasympathetic denervation of SMGs by cleaving SNAP-25.

CONCLUSIONS

BoNT/A temporarily caused MEC atrophy and decreased MEC contractility in rat SMGs, which contributed to reversible inhibition of salivary secretion. The underlying mechanisms involved temporary parasympathetic denervation caused by SNAP-25 cleavage. These findings provide new insights into the mechanisms of BoNT/A-inhibited salivary secretion.

Comparing botulinum toxin and 4-duct ligation for Sialorrhea in children - A systematic review

INTRODUCTION

Sialorrhea or drooling can result in physical and psychosocial complications, such as aspiration and social isolation. Treatment options include botulinum toxin into the salivary glands and 4-duct ligation (i.e., simultaneous ligation of the bilateral parotid and submandibular ducts). This systematic review aimed to compare the efficacy and complication rates of botulinum toxin and 4-duct ligation for the treatment of drooling in children.

METHODS

Following PRISMA guidelines, PubMed, Embase, Web of Science, and Cochrane Library were searched from inception through June 17, 2021 for studies examining the efficacy of botulinum toxin or 4-duct ligation for drooling in children. Data were summarized by pooled counts, percentages, and means. Complication rates were compared by a chi-squared test.

RESULTS

A total of 22 studies (n = 606) examining botulinum toxin and 5 studies (n = 124) examining 4-duct ligation were included. From 12 botulinum toxin studies (n = 211), mean drooling frequency and severity scores was 7.5 at baseline. Mean difference from baseline was -2.6 (n = 92) at 4 weeks follow-up, -2.1 at 8 weeks (n = 41), -2.1 at 12 weeks (n = 56), and - 2.1 at 16 weeks (n = 58). From 4 4-duct ligation studies (n = 103), mean baseline drooling frequency and severity score was 8.4. Mean difference was -3.7 at mean follow-up of 35.6 months (n = 103). Eighteen botulinum studies (n = 343) recorded 53 (15.5 %) complications, including thickened saliva (n = 9), dysphagia (n = 4), and cheek abscesses (n = 4). Four 4-duct ligation studies (n = 108) recorded 25 (23.1 %) complications, including parotid gland swelling (n = 4), aspiration pneumonia (n = 3), and oxygen desaturation (n = 3). There was no statistically significant difference in complication rates between botulinum toxin and four-duct ligation (p = 0.065).

CONCLUSION

Botulinum toxin injection and 4-duct ligation are both effective in improving sialorrhea in children and have comparable complication rates.

The effectiveness and safety of botulinum toxin injections for the treatment of sialorrhea with Parkinson's disease: a systematic review and meta-analysis

BACKGROUND

Botulinum toxin (BoNT) injection is an important adjunctive method to treat sialorrhea. The purpose of this systematic review was to analyze the effect and safety of BoNT injections in the intervention of sialorrhea with Parkinson's disease (PD).

METHODS

We searched PubMed, Web Of Science (WOS), Scopus, Cochrane CENTRAL, and Embase from inception until April 2022. Randomized controlled trials or randomized crossover trials comparing BoNT with placebo in sialorrhea with PD were eligible. PRISMA guidelines were used to carry out the meta-analysis. The Drooling Severity Frequency Scale (DSFS) score and the number of adverse events (AEs) were the primary and secondary outcomes, respectively. Standardized mean differences (SMDs) and risk differences (RDs) are used to express continuous and categorical outcomes, respectively. Heterogeneity among these studies was evaluated using I2 tests. We used the GRADE tool to assess the certainty of evidence (COE).

RESULTS

Eight articles involving 259 patients compared BoNT injections with a placebo for PD with sialorrhea. This meta-analysis showed a significant reduction in DSFS scores between BoNT injections and placebo (SMD=-0.98; 95% CI, -1.27 to 0.70, p<0.001; COE: high). This meta-analysis showed a significant difference in AEs between BoNT injections and placebo (RD=0.15; 95% CI, 0.05 to 0.24, p=0.002; COE: low).

CONCLUSIONS

The pooled results suggest that BoNT injections have some effect on DSFS scores with sialorrhea caused by PD. There are also mild adverse events, which generally recover within a week or so. The results indicate that BoNT injection is one of the treatments for sialorrhea caused by PD, but we need to pay attention to adverse events. In addition, the follow-up time was extended to observe oral hygiene, ulceration or dental caries, and digestive function.

TRIAL REGISTRATION

Our review protocol was registered on PROSPERO (42021288334).

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.

Placebo-Controlled Clinical Trial of IncobotulinumtoxinA for Sialorrhea in Children: SIPEXI

BACKGROUND AND OBJECTIVES

To investigate the efficacy and safety of repeated injections of incobotulinumtoxinA (incoBoNT/A) for treatment of chronic sialorrhea (drooling) associated with neurologic disorders (e.g., cerebral palsy, traumatic brain injury) or intellectual disability in children and adolescents in a prospective phase III study (SIPEXI [Sialorrhea Pediatric Xeomin Investigation]).

METHODS

The study enrolled 2- to 17-year-old patients with sialorrhea due to neurologic disorders or intellectual disability. Patients received body weight-dependent doses of incoBoNT/A (20-75 U). A main period with 1 injection cycle (placebo-controlled, double-blind, 6- to 17-year-olds) was followed by an open-label extension with up to 3 further cycles. An additional cohort of 2- to 5-year-olds received active treatment throughout the study. Coprimary endpoints were the change in unstimulated salivary flow rate (uSFR) from baseline to week 4 and the carers' Global Impression of Change Scale (GICS) rating at week 4. Adverse events were recorded.

RESULTS

In the main period, 220 patients aged 6-17 years were randomized and treated (148 patients in incoBoNT/A group, 72 patients in placebo group). A total of 35 patients aged 2-5 years received incoBoNT/A (no placebo). A total of 214 patients aged 6-17 years and 33 patients aged 2-5 years continued treatment in the open-label extension period. For the 6- to 17-year-olds, a significant difference between incoBoNT/A and placebo was seen in mean uSFR decrease (difference -0.06 g/min; p = 0.0012) and the carers' GICS rating (difference 0.28 points; p = 0.032) at week 4, in favor of active treatment. The secondary endpoints consistently supported these results. A sustained benefit was observed during the extension. Incidences of adverse events were comparable between incoBoNT/A and placebo and did not increase notably with repeated injections. The most common adverse events were respiratory infections. Efficacy and safety were also favorable in the uncontrolled cohort of 2- to 5-year-olds.

DISCUSSION

Both co-primary efficacy endpoints were reached and superiority of incoBoNT/A over placebo was confirmed. IncoBoNT/A (up to 75 U, up to 4 cycles) is an effective and well-tolerated treatment for sialorrhea associated with neurologic disorders in children.

TRIAL REGISTRATION INFORMATION

Clinicaltrials.gov: NCT02270736 (clinicaltrials.gov/ct2/show/results/NCT02270736); EU Clinical Trials Register: 2013-004532-30 (clinicaltrialsregister.eu/ctr-search/search?query=2013-004532-30).

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that injection of incobotulinumtoxinA decreases drooling in children aged 6 to 17 years with neurologic disorders.

Percutaneous Salivary Gland Ablation using Ethanol in a Rat Model

Objectives

Sialorrhea is a common health and psychosocial problem for children with neuromuscular dysfunction secondary to a variety of disorders such as cerebral palsy. Current accepted treatments include the injection of botulinum toxin into the submandibular glands for temporary symptom relief. The purpose of this study is to demonstrate the feasibility of percutaneous ethanol injection for longer lasting salivary gland ablation in an animal model.

Material and Methods

Twenty rats were used in this study. In each rat, 98% ethanol was injected into the right submandibular gland under ultrasound guidance. No intervention was performed on the left gland, which served as the control. Ten rats were sacrificed and glands evaluated at three weeks, with the remaining 10 rats sacrificed and evaluated at three months. Unpaired, 1-tailed T-tests were used to analyse the data.

Results

Ethanol injections induced a significant and sustained reduction in salivary gland size. Treated glands were 41% smaller by mass than untreated controls in the 10 rats sacrificed at three weeks (P < 0.001). Treated glands were 43% smaller by mass than untreated controls in the 10 rats sacrificed at three months (P < 0.001). Qualitative histologic analysis demonstrated extensive parenchymal damage, inflammation, and fibrosis at both three week and three month time points.

Conclusions

Using a rat model, we demonstrated dramatic and sustained submandibular gland damage after percutaneous injection of ethanol.

BOTOX-A injection of salivary glands for drooling

BACKGROUND AND PURPOSE

Drooling is a challenging entity to manage. Botulinum toxin A (BOTOX-A) infiltration of salivary glands is a promising alternative to surgical treatment. This study aims to assess the outcome of BOTOX-A salivary glands infiltration in children with drooling.

METHODS

Patients treated between January 2012 and March 2015 were enrolled. BOTOX-A was injected in the parotid and submandibular glands under ultrasound control and general inhalational anesthesia. The outcome was evaluated through the DSFS: Drooling Severity (1-best to 5-worst) and Frequency (1 to 4) Scale, that was applied before treatment, and 1-, 3-, and 6-month after injection. The inclusion criteria were a DSS ≥4 and/or DFS ≥3. Statistical significance was set at 5%.

RESULTS

There were 17 patients aged 12.1±5.1 [4-19]years, all of them with neurologic impairment. After the first injection, 13 (76.5%) patients had reduction of the severity (S) and 12 (70.6%) of the frequency (F) scale; in 6 (35.5%) patients drooling resolved completely. Pre-treatment S+F score was 8.59±0.71 [7-9]; it decreased significantly to 4.65±2.32 (p=0.001) at 1-month post-injection evaluation. At 3-month and 6-month the scores were also significantly lower than the pre-treatment one (4.00±1.96, p=0.002; 5.36±2.20, p=0.005; respectively), but there was a significant increase between the 3-month and 6-month evaluations (p=0.01). With a follow-up of 20.1±9.2 [4-38] months, 4 out of the 13 successful injections needed a second one after 7.5±3.1 [3-10] months. The patient with the longest time not requiring re-injection had 28months of follow-up. One (6%) patient presented mild dysphagia that regressed spontaneously. All but two (88%) parents/caregivers would repeat the treatment.

CONCLUSIONS

BOTOX-A seems to be an effective minimal invasive treatment for drooling with few complications. After 6months the need for re-injection becomes substantial but it may not be necessary for several months. Further studies are needed to establish the most effective dosage and frequency of injections.

LEVEL OF EVIDENCE

IV.