Introduction
Whilst there are numerous reports in the literature of surgical treatment for drooling, they tend to refer only to the child with global neurological impairment, most commonly cerebral palsy. A diagnosis of oro-motor or oro-facial dyspraxia is increasingly given to children with coordination difficulties affecting the tongue, oral cavity and buccal musculature. The child may present with drooling as their only or main problem, in the absence of any sensory deficit or other neurological problem. Oro-motor dyspraxia is a specific type of developmental dyspraxia in which the child has difficulty making and/or coordinating movements of the oro-facial muscles. Current management strategies tend to rely almost entirely on speech and language therapy. A surgical approach to the treatment of drooling in these patients has not previously been reported; we present a case in which it was very successful.
Case report
A seven-year-old girl was referred with constant drooling. She had been delivered two weeks post-term by Caesarean section after an unremarkable pregnancy, and had no significant medical problems. Her motor development had been slow; she had not begun to walk until 22 months and had always had some difficulties with voluntary tongue movement. She had begun to talk at a normal age, with no concerns regarding articulation, and there had never been problems with sucking, chewing or swallowing. There had been no focal neurological abnormalities. A diagnosis of oro-motor dyspraxia had been made by a paediatric neurologist. The patient had drooled constantly from a young age, and had continued to do so despite extensive speech therapy using oro-motor exercises. Hyoscine hydrobromide (scopolamine) patches had not helped, and she had developed a local skin reaction to them and had had to discontinue use. She was becoming increasingly aware of her drooling as a social problem, and continued to soak several shirts daily.
An ENT examination was unremarkable except for generally reduced tongue mobility. There were no concerns regarding the patient's swallow.
It was felt that behavioural therapies had failed, and the patient's parents were not in favour of any further medical treatment; rather, they wanted a permanent solution. It was decided to proceed with bilateral submandibular duct transposition. Submandibular duct transposition is the first-line surgical procedure in our institution (and many others) for drooling in the child who does not aspirate.
The procedure was performed in the standard manner with no complications. At the patient's six-week follow-up appointment, significant improvement in her drooling was noted. By seven months post-surgery, there were no residual problems.
Discussion
Oro-facial praxis is the ability to plan and execute movements or sequences of movements using the pharyngobuccal or oro-facial muscles. Praxis is learned, developing from the age of two years, with most children having consistent praxis by six years of age.Reference Bearzotti, Tavano and Fabbro1 Oro-motor (also called oral or oro-facial) dyspraxia is a developmental motor planning problem, which may present with feeding difficulties and speech problems as well as drooling.Reference Simms2 Whilst there may be oro-facial problems alone, many children have associated generalised motor incoordination. These children have previously been given the ‘clumsy child’ label, but the problem now tends to be referred to as developmental dyspraxia.Reference Dewey3 However, there is still no true consensus regarding the exact definition of this problem, also commonly referred to as ‘developmental coordination disorder’. There is a spectrum of ‘normality’ in such conditions, but the absence of any known neurological condition or intellectual impairment is a prerequisite for the diagnosis.4
Overall, oro-motor dyspraxia is an ill-defined and poorly understood condition, the diagnosis of which requires specialist input. Rarely does it present with drooling as the only symptom, and there are often associated problems with tongue movement and buccal muscle control. There may be an associated speech delay. Two distinct subtypes are recognised, oral dyspraxia and verbal dyspraxia. Children with oral dyspraxia have difficulty making and coordinating movements of the oral and buccal musculature unrelated to speech production. For example, they may have problems pursing their lips, blowing out their cheeks or making tongue movements. Verbal dyspraxia causes problems with the production and coordination of specific articulatory movements required for clear speech sounds. The two are not always found together; a child with no speech problems at all may present with isolated oral dyspraxia, and vice versa.Reference Gibbs, Appleton and Appleton5
Various medical and surgical treatment options for drooling have been reported in the literature; surgical approaches have been widely discussed.Reference Bailey6–Reference Crysdale, Greenberg, Koheil and Moran11 A minor degree of drooling is normal in the infant, but when it persists in an older child it becomes a problem, both from a social point of view and for the parents or carers, who may need to change the child's bibs or clothes several times each day. In severe cases, the skin of the chin can become macerated. Drooling is most commonly seen in children with cerebral palsy, but can occur with other neuromuscular or intellectual impairments or, as discussed here, in otherwise ‘normal’, healthy children. It is not caused by excessive salivary production, but rather by infrequent or inadequate swallowing of saliva.
First-line management of the drooling child must include a thorough neurological evaluation if there is no underlying diagnosis. Speech and language therapy should be started as early as possible, particularly in children with a diagnosis of oro-motor dyspraxia, and may produce good results.Reference Bailey6 Medical treatment with hyoscine hydrobromide patches is the next step, although the side effects are often not tolerated at the dose required to dry the mouth satisfactorily.Reference Hussein, Kershaw, Tahmassebi and Fayle7 These include blurred vision, drowsiness, difficulty with micturition and local skin reactions.Reference Nunn9 Botulinum toxin injections into major salivary glands has been used with some success,Reference Crysdale, McCann, Roske, Joseph, Semenuk and Chait10 although the effects are obviously only temporary and general anaesthesia may be required each time the procedure is repeated.
If conservative measures fail, surgical options include tympanic neurectomy, excision of the submandibular glands, submandibular or parotid duct ligation, and submandibular duct transposition.Reference Bailey and Wadsworth12 As 80–90 per cent of resting salivary production is by the submandibular and sublingual glands, submandibular gland excision or duct rerouting are popular techniques. The Wilke procedure, namely bilateral parotid duct retropositioning and bilateral submandibular gland excision, was one of the first commonly used procedures.Reference Wilke13 It has been shown to have a high success rate in controlling drooling in children with cerebral palsy,Reference Puckett, Concannon, McNaul and Barone14 but is a relatively major operation with a high morbidity rate.Reference Bailey6
Submandibular duct transposition is a low morbidity procedure with no external scars and a low rate of complications, the main one being ranula formation in up to 8 per cent of cases.Reference Crysdale, Greenberg, Koheil and Moran11 This procedure has been shown to have a good outcome in 80 per cent of children, with greater improvement seen in cases with a lower pre-operative neurological deficit score.Reference Mankarious, Bottrill, Huchzermeyer and Bailey15 This suggests that, in children with no neurological impairment, the success rate should be excellent. Quality of life scores have been shown to improve substantially following this procedure.Reference Syeda, Ahsan and Nunez16 A large series of children with ‘saliva control issues’ treated in a multidisciplinary clinic has been reported. Despite the use of behavioural and other conservative measures, 57 per cent were thought to require surgery even at their initial visit, and bilateral submandibular duct transposition was the procedure of choice for non-aspirating children, often combined with sublingual gland excision.Reference Crysdale, McCann, Roske, Joseph, Semenuk and Chait10 The results were excellent and complications rare.
Whilst most of the literature discusses the management of drooling in children with cerebral palsy or other neurological problems, there are reports of drooling in the ‘normal’ child. One study evaluated quality of life ratings in nine children before and after submandibular duct transposition for drooling. Two of these children had no underlying medical problem, two were diagnosed with ‘motor skills disorder’ and one was an asthmatic child with rhinitis. No further information about these children was reported, nor did the results separate neurologically-impaired patients from ‘normal’ cases. The authors reported an overall improvement in quality of life following surgery, but two children failed to show any improvement and their underlying diagnosis (or lack thereof) was not documented.Reference Syeda, Ahsan and Nunez16
• Isolated oro-motor dyspraxia is an unusual diagnosis in which the child may present with drooling as their only or main problem
• Conservative management of drooling in any child, whatever the underlying cause, is often not satisfactory
• Surgery can be beneficial; the presented patient was successfully treated with bilateral submandibular duct transposition
• Underlying neurological problems must be excluded first, and patients carefully selected
Talmon et al. reported their experience of submandibular duct transposition for drooling in ‘otherwise healthy’ children, in 1981.Reference Talmon, Podoshin and Fradis17 They performed unilateral transposition in six children and bilateral transposition in one child, and reported excellent results. There was no mention of any diagnoses of oro-motor dyspraxia, and the children were all rather young (aged three to seven years). It is therefore possible that these children were still developing their oral praxis, and that surgical intervention had been undertaken somewhat prematurely. Indeed, follow up of such children over several years has shown that drooling tends to cease between 3.1 and 8.3 years, with a mean age of five years.Reference Johnson, King and Reddihough18 This study by Johnson et al, also reviewed ‘normal’ children, with no medical diagnosis, but 35 per cent of their patients also had some difficulties eating ‘hard’ food, and the authors admitted that ‘no information was gathered on general behavioural issues, learning abilities, fine motor difficulties or cognitive skills’. Perhaps some of these children were suffering from oro-motor dyspraxia, but the diagnosis was not discussed.
Conclusion
Oro-motor dyspraxia is an unusual cause of drooling, but as a diagnosis it is becoming more commonly seen. Conservative management of drooling in any child, whatever the underlying cause, is often not satisfactory. There are currently no reports in the literature of surgery for persistent drooling in children with oro-motor dyspraxia who are otherwise neurologically and developmentally normal. Such surgery can be beneficial, as shown by our patient who was successfully treated with bilateral submandibular duct transposition. Underlying neurological problems must be excluded first, and the patients carefully selected.
