Use of botulinum neurotoxin A in uncontrolled salivation in children with cerebral palsy: a pilot study

Abstract

This study investigated the safety and efficacy of botulinum neurotoxin type-A (BNT-A) injections into the salivary glands for treatment of sialorrhea in children with cerebral palsy (CP) and assessed the clinical factors that affect treatment outcome. The parotid and submandibular glands of nine CP patients were injected with BNT-A 1.4 U/kg in each parotid gland, and 0.6 U/kg in each submandibular gland. All children had neurological disorders. Gross motor function classification system levels ranged from I to V. All children had moderate to severe intellectual disability. A telephone interview with one parent determined response to treatment. Drooling intensity and frequency were measured with the drooling severity and frequency scale. After BNT-A treatment, the patients were followed up for 6 months using self-assessed rating scales for drooling intensity, discomfort and treatment effect (drooling impact scale). All parents reported an improvement in sialorrhea in the first week. Drooling was very intensive at baseline, and moderate 2 weeks after treatment. Maximum response occurred at 2–8 weeks. The use of BNT-A in uncontrolled salivation in children with CP can be considered acceptable and effective. Malocclusion and anterior salivation are closely related clinical characteristics and should be taken into account when planning treatment.

Xerostomia is one of the first manifestations of botulism, which prompted investigations of its application for treating drooling. Botulinum neurotoxin (BNT) was the first bacterial toxin used as a medicine. Its clinical applications have been expanding over the last 30 years and novel possibilities are reported. Acetylcholine acts as a neurotransmitter for innervation of muscles and gland tissues. Blocking the release of leads to a reduction in pathological movements of muscles and secretion of glands. Intraglandular delivery of botulinum neurotoxin type-A (BNT-A) inhibits the release of acetylcholine from cholinergic nerve endings and consequently reduces the secretion of saliva and diminishes drooling in the majority of patients. It has a temporary paralytic effect.

Insufficient control of the coordinate mechanism of the orofacial, palatolingual, and head and neck musculature results in excessive pooling of saliva in the anterior part of the oral cavity and unintentional saliva loss. The problem is mostly related to disturbed glutition rather than hypersalivation in children with cerebral palsy (CP).

BNT-A is used in uncontrolled salivation in neurologically impaired children. Drooling is a significant disability for a large number of paediatric patients with CP and other types of neurological and cognitive impairment.

A number of treatments have been developed to reduce it. Oral-motor programmes to improve oral-motor function are essential initially if there is patient compliance. The possible pharmacological approaches include anticholinergic drugs. Surgical treatment remains the last resort for patients with profound sialorrhea who have failed conservative management. Submandibular duct relocation with simultaneous sublingual gland excision remains the procedure of first choice for persistent significant drooling.

Simultaneous ligation of the submandibular and parotid ducts is promising. A recent initiative to inject the major salivary glands with BNT is being evaluated. Many factors contribute to the passage of saliva from the oral cavity to the oesophagus, such as the child’s mental abilities, the cognitive awareness of social norms, an intact swallowing mechanism, oral sensibility, lip closure, and the ability to hold the head in an upright position. Sialorrhea is a problem which can lead to many complications, such as aspiration pneumonia, skin maceration, and dental caries. The constant presence of saliva may impair articulation and effective communication. All of these complications negatively affect the quality of life of patients and their families. Uncontrolled salivation affects the child and the family and caretakers, decreasing their quality of life.

With respect to aetiology and clinical impact, it is advisable to distinguish anterior drooling from posterior drooling. Saliva spilled from the mouth is referred to as anterior drooling, which is clearly visible. In the case of posterior drooling, saliva is spilled through the faucial isthmus creating a risk of aspiration. Inadequate lip closure, habitual open-mouth posture, ineffective or limited tongue movements, poor coordination between the oral and pharyngeal stages of swallowing, malocclusion, flexed posture, gingivitis and dental caries may contribute to the origin of drooling.

The aim of the present study was to investigate the safety and efficacy of BNT-A injections into the salivary glands for treatment of sialorrhea in children with CP and to elucidate the clinical factors that play a role in the outcome of the treatment.

Patients and methods

12 children were identified with CP, three of them were excluded because their parents declined to participate in the study. Nine paediatric patients with CP (four male and five female, aged 1.6–11 years, weight 10–30 kg), admitted to the Department of Neurology and Neurorehabilitation of the Children’s Clinic of Tartu University Hospital, were screened from January 2011 to August 2011. All children had moderate to severe intellectual disability and three of them had epilepsy. Four children had spastic and five had dyskinetic movement disorder: four of them were wheelchair dependent. In four cases the aetiology of CP was birth hypoxia. The study was approved by the Ethics Committee on Human Research of the University of Tartu (protocol No. 192/T-3; 26.04.2010). The parents’ written informed consent was obtained. Children with moderate and severe sialorrhea were enrolled in a descriptive, non-blinded prospective study. The present study evaluates several clinical factors that play a role in the outcome of drooling treatment. These clinical parameters are dental status, malocclusion, oral motor performance, mouth closure, lip seal, anterior or posterior drooling, speech, and swallowing.

All patients had oral motor hyper-tonicity and eight of them had slow uncoordinated tongue movements, insufficient lip closure and malocclusion (mostly open bite). Four children had breathing problems because of saliva aspiration and two of them needed a tracheostomy. A gastrostoma was used due to feeding and swallowing difficulties in four cases. Anterior drooling occurred in five cases, posterior drooling in three cases, and one patient had both.

Evaluation of drooling

In all enrolled children, drooling was evaluated subjectively and objectively using standardized parameters. Subjective evaluation was rated by the parent or caregiver using the drooling severity and frequency scale (DSFS ) which summarizes severity and frequency subscores ( Tables 1 and 2 ). This scale quantifies the severity and frequency of sialorrhoea on a scale of 2–9. The domain specifically focusing on the severity of drooling ranges from one (no drooling) to five (profuse drooling). The domain for frequency ranges from one (no drooling) to four (constant drooling).

Table 1
Drooling severity and frequency scale (DSFS).
Drooling severity scale
1 = Never drools, dry
2 = Mild – drooling, only lips wet
3 = Moderate – drool reaches the lips and chin
4 = Severe – drool drips off chin and onto clothing
5 = Profuse – drooling off the body and onto objects (furniture, books)
Drooling frequency scale
1 = No drooling
2 = Occasionally drools
3 = Frequently drools
4 = Constant drooling

Table 2
Questionnaire-based scoring system for drooling severity and frequency according to DSFS.
Drooling severity (Average) Drooling frequency (Average) DSFS (Average)
Baseline 4.3 3.3 7.6
Week 2 2.3 1.8 4.1
Week 4 2.3 2 4.3
Week 6 2.4 2 4.4
Week 8 2.7 2.2 4.9
Week 10 3.2 2.8 6
Week 12 3.8 3.3 7.1

Visual analogue scales (VAS ) rating the parents’ opinion were applied. Evaluation of drooling frequency by VAS was measured according to the number of bib changes per day ( Table 3 ) and the number of cases needing aspiration per day ( Table 4 ). A detailed questionnaire was developed to evaluate the impact of drooling on the items of daily life. Table 5 shows the sensitivity of the drooling impact scale. To assist evaluation of the clinimetric properties of the scale, the parents or caregivers were also asked to rate, on a four-point scale, the degree to which drooling had increased or decreased after treatment, as well as the accompanying quality of life. A score of four was categorized as significant reduction in drooling, three as marked reduction, two as moderate reduction, one as mild reduction and zero as no reduction.

Table 3
Data for the subjective evaluation of drooling by the number of bib changes per 24 h.
Patient Evaluation (bibs/24 h) Baseline Weeks
2 4 6 8 10 12 14 16 18
1 Bib change 6 or 7 5 or 6 5 or 6 5 or 6 5 or 6 6 No effect
2 Bib change 2 1 1 1 1 or 2 1 or 2 No effect
4 Bib change 10 3 3 2 2 2 4 or 5 No effect
5 Bib change and aspiration 4 or 5 1 1 1 3 or 4 No effect
6 Bib change and aspiration 10 4 or 5 4 or 5 4 or 5 4 or 5 5 or 6 6 or 7 7 or 8 No effect
7 Bib change 4 or 5 1 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 1 or 2 3 or 4 3 or 4
8 Bib change 8 8 No effect
9 Bib change and aspiration 1 or 2 0 0 0 or 1 0 or 1 0 or 1 0 or 1 1 or 2 3 or 4 3 or 4
Average 5.875 3 2.937 2.875 3.313 3.625 4.25 5.188 5.75
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Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Use of botulinum neurotoxin A in uncontrolled salivation in children with cerebral palsy: a pilot study
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