Sialorrhea In Children Research Articles

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Introduction Intraglandular injection of botulinum toxin A into the salivary glands is the effective treatment option for sialorrhoea in children with cerebral palsy or other neurological diseases without any severe side-effects. It results in transient denervation of the gland, which helps in reducing salivary secretion. The aim of this study was to evaluate histological changes in the rats’ parotid glands after accidental or intended intraglandular injection of botulinum toxin A in patients with bruxism or sialorrhoea. Materials and methods After 20 days of the botulinum toxin A injection, tissue specimens of the right parotid gland were obtained from 15 albino rats, while the specimens of left parotid gland were used as control. Ordinary light microscopy and electron microscopy were used to detect the morphological changes in the injected parotid glands. Results Morphological and ultrastructural analyses of the cell organelles and secretory granules showed a clear atrophy of the acini in glands injected with the botulinum toxin A. Acinar cells revealed significant morphologic variations in rough endoplasmic reticulum and degenerated mitochondria. There was a considerable variation in the size, shape and electron density of secretory vacuoles. The nucleus had an irregular shape and finely dispersed chromatin. Conclusion Intraglandular injection of botulinum toxin A induces structural and functional changes of the salivary glands, indicated by glandular atrophy. Thus, injection of botulinum toxin A into the salivary glands at a relatively low dose can be used as a treatment of choice for sialorrhoea. This is an easily performed procedure with low morbidity, and can be recommended as a first-line intervention in the treatment of adult sialorrhoea.

Long-term Safety and Efficacy Data on Botulinum Toxin Type A

To evaluate the safety and efficacy data on salivary gland injection botulinum toxin type A for the treatment of sialorrhea. Retrospective cohort study in a tertiary academic children's hospital. A 10-year review (January 1, 2001, through December 31, 2010) of 69 children with sialorrhea who had undergone salivary gland injection of botulinum toxin type A. Injection of botulinum toxin type A to the submandibular and parotid glands. Postinjection complications, supplemental treatments, and caregiver satisfaction. A total of 69 children were included in the study (42 boys and 27 girls). The first injection was given at a mean age of 9.9 years with a mean follow-up of 3.1 years. Children underwent ultrasonography-guided 4-gland injection at a constant dosage range. The telephone survey response rate was 51%. Postinjection complications occurred in 19 patients (23 events)-14 (15 events) with minor and 5 (8 events) with major complications. Major complications included aspiration pneumonia (n = 3), severe dysphagia (n = 2), and loss of motor control of the head (n = 3), resulting in 5 hospitalizations and 2 nasogastric tube insertions. Complications were not associated with demographic or clinical factors except for a male preponderance (P = .05). Satisfaction scores were evenly distributed among respondents. Thirty-one children (45%) required supplemental treatments: medical treatment alone (n = 21), surgical treatment alone (n = 2), and combined medical and surgical treatment (n = 8). Although our complication rate is within the published range, some of the major complications had significant morbidity. A subsequent surgical rate of 15% suggests the efficacy is less than universal. Thus, botulinum toxin type A injection for sialorrhea in children is a useful tool but has safety and efficacy limitations.

Multidisciplinary management of sialorrhea in children

Multidisciplinary management of sialorrhea in children

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

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 1.4U/kg in each parotid gland, and 0.6U/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.

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

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. 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. 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. 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.

Contemporary Surgical Management of Severe Sialorrhea in Children

The causes of severe sialorrhea (drooling) are reviewed, and in particular in children in whom it can become a life-long disability. The history of medical and surgical treatments is discussed. A major advance has been the surgical relocation of the submandibular gland ducts with removal of sublingual glands. The results of this operation, technical considerations, and its outcomes in 16 children are presented. There were no significant complications. Caregivers judged the efficacy with a median score of “75%” improvement. The technique has become the most logical and reliable surgical treatment for drooling, with very good control in most cases. In contrast to “Botox” its effects are permanent.

Effect of Botulinum Toxin A Injection into the Salivary Glands for Sialorrhea in Children with Neurologic Disorders

ObjectiveTo determine the 9 month period effect of botulinum toxin A (BoNT-A) injection into the salivary gland in children with neurologic disorders and sialorrhea by qualified parent/caregiver-administered questionnaires.MethodA total of 17 patients (age 7.6±4.24 years) were enrolled in this study. The degree of sialorrhea was assessed at the baseline, 2 weeks, 1, 2, 4, 6 and 9 months after injection. The Drooling Count (DC) was assessed as an objective measurement. The Drooling Frequency and Severity Scale (DFS) and the Teacher Drooling Scale (TDS) were evaluated as a subjective measurement. BoNT-A (0.5 unit/kg) was injected into each submandibular and parotid gland under ultrasonography-guidance.ResultsDC, DFS and TDS showed significant improvement at 2 weeks, 1, 2, 4, 6, and 9 months follow-up (p<0.05). Twelve of 17 cases (70.5%) showed more than 50% reduction in DC from the baseline value.ConclusionUltrasonography-guided BoNT-A injection into the submandibular and parotid gland was a safe and effective method to treat sialorrhea in children with neurologic disorders.

Botulinum toxin type B for sialorrhoea in children with cerebral palsy: a randomized trial comparing three doses

The aim of the present study was to evaluate the efficacy and safety of three doses of botulinum toxin type B (BoNT-B) in reducing persistent sialorrhoea in children with cerebral palsy (CP). Children with CP and refractory sialorrhoea were randomized to one of four groups: a control group and three experimental groups receiving a low (1500 mouse units [MU]), medium (3000 MU), or high (5000 MU) dose of BoNT-B respectively, into bilateral salivary glands. Drooling was measured using the Thomas-Stonell rating scale, and the weight and the number of bibs used per day were counted in all children at baseline, 4, and 12 weeks after BoNT-B injection. Twenty-seven children (15 males, 12 females; mean age 7 y 10 mo, SD 1 y 6 mo; range 5-15 y) were randomized into a control (seven children: four males, three females) and experimental groups receiving low (six children: four males, two females), medium (seven children: four males, three females), and high (seven children: three males, four females) doses of BoNT-B respectively. All children had mixed neurological disorders consisting of spastic paraparesis, tetraparesis, dystonic movements, and ataxia. Gross Motor Function Classification System levels ranged from III to V, and all children had moderate or severe intellectual disability. Estimated means with their standard errors (SEM) of drooling were at baseline, 4, and 12 weeks respectively, as follows: control group, 12.1 (2.1), 11.9 (2.1), 11.8 (2.2), p for trend 0.992; low dose group, 13.8 (2.3), 11.4 (2.3), 13.9 (2.3), p for trend 0.952; medium dose group, 13.9 (2.1), 6.7 (2.1), 7.1 (2.1) p for trend 0.008; and for the high dose group 14.4 (2.1), 5.0 (2.1), 5.6 (2.1), p for trend 0.002. Side effects included dense saliva, xerostomia, and difficulty in swallowing, and were more frequent in the high-dose group. A 3000 MU injection of BoNT-B into the salivary glands significantly improved the frequency and severity of sialorrhoea in children with CP. The lower dose was ineffective, and the higher dose produced no greater benefit and more side effects.

Botulinum Toxin A for Treatment of Sialorrhea in Children

To report (1) our experience with botulinum toxin A injections into the salivary glands of pediatric patients with sialorrhea, (2) the clinical outcomes of these interventions, and (3) the associated complication rates. Retrospective cohort study. Urban pediatric hospital and pediatric rehabilitation center. Forty-five neurologically impaired children. Patients received botulinum toxin A intrasalivary injections between January 2004 and May 2008 at the Hospital for Sick Children in Toronto, Ontario, Canada. All patients received sedation or general anesthesia for their botulinum toxin A injections, which were performed using ultrasonographic guidance. Posttreatment assessments included the duration of effect, patient complications, saliva consistency, caregiver willingness to repeat the treatment, caregiver satisfaction with the treatment, and caregiver overall assessment of the child's posttreatment quality of life. Forty-five subjects received a total of 91 botulinum toxin A treatments. The mean (SD) duration of effect was 4.6 (5.2) months. Duration of effect (log transformed) was significantly negatively associated with saliva quantity (P=.02), and there was a positive association with both increasing age and female sex, although neither reached statistical significance (P=.08 for each). Seven of the 24 documented complications were major, according to the Society of Interventional Radiology Classification System for Complications by Outcome scale. Thirty-six of the caregivers reported that this treatment improved the child's quality of life (80%). Ultrasonographically guided botulinum toxin A injections into the salivary glands are safe and efficacious in the management of sialorrhea in children with neurologic disorders.

Treatment of sialorrhea in children with Cerebral Palsy: A double-blind placebo controlled trial

Objectives To prospectively study the efficacy and safety of intraparotid gland injection of Botulinum neurotoxin serotype A (Dysport ®) for the treatment of sialorrhea (drooling) in children with cerebral palsy (CP). Patients and methods Twenty-four children, ages 21 months to 7 years, were recruited and randomized to receive either treatment with 100 U Botulinum toxin or placebo. Rating scales for the frequency and severity of drooling were performed at the time of injection, at 1 month, and at baseline prior to the second injection. A second set of injections of either 140 U of drug or placebo was given 4 months later, and the same rating scales were used. Eight patients declined the second injection. Due to high dropouts in the placebo group in second set of injections, statistical analysis was performed for the results of the initial injection only. Results Scores of the median frequency ( p = 0.034) and severity ( p = 0.026) of drooling were reduced in the treatment group. Median total score also declined in the treatment group ( p = 0.027). After the second injection, five out of nine patients injected with the drug showed a decline in the total score; including three patients who did not respond to the first injection. Only two patients experienced transient increase in drooling after the treatment with the drug. Conclusion Botulinum toxin is an effective and safe treatment option for drooling in children with CP.

Successful Treatment of Drooling in Children with Neurological Disorders with Botulinum Toxin A or B

Drooling is a common and severe problem in children with neurological disorders and is caused by a disturbed coordination of orofacial and palatolingual muscles. Botulinum toxin could be a successful option to reduce excessive sialorrhea in children with neurological disorders. In 30 children with cerebral palsy or neurodegenerative disorder we injected under ultrasound guidance either botulinum toxin A or botulinum toxin B into the parotid and submandibular glands on both sides. All injections were well tolerated without general anaesthesia. Drooling severity at baseline and reduction of sialorrhea during treatment was measured using a parent's questionnaire and rated using the Teachers Drooling Scale (TDS). Reduction of sialorrhea was achieved two weeks after injection, with a positive effect lasting about three to four months in most children. 83% showed a good response to botulinum toxin after first injection, but only in 50% treatment was continued. We found no significant differences between botulinum toxin A or B. Side effects were observed in 5 children with viscous saliva and in one child a unilateral parotitis was observed. Treatment of drooling with botulinum toxin into the salivary glands is a safe and easy therapeutic option for children with neurological disorders to improve life quality.

Botulinum Toxin A in the Treatment of Sialorrhea in Children with Cerebral Palsy

Sialorrhea is commonly associated with many neurological and systemic conditions. For children and young adults with cerebral palsy, sialorrhea may cause embarrassment and social isolation. Current medical management used for sialorrhea is unsatisfactory. Preliminary studies in adults with sialorrhea have demonstrated that botulinum toxin A as an effective treatment; however, no studies have defined the optimal dose and the duration of botulinum toxin A's effects on sialorrhea in patients with cerebral palsy. We present four patients with cerebral palsy who received botulinum toxin A treatment for sialorrhea. Under ultrasound guidance, body weight-related dosage of botulinum toxin A was injected bilaterally into the parotid glands. All four patients reported distinct improvement within the first 2 weeks following toxin injection. Duration of the toxin's effect varied from 16 to 20 weeks. There were no therapeutic side effects.

Parotid and submandibular botulinum toxin A injections for sialorrhoea in children with cerebral palsy

The aim of this study was to determine whether botulinum toxin A (BTX‐A) injected into the parotid and submandibular salivary glands of children aged 6 to 16 years with cerebral palsy (CP) and relative sialorrhoea significantly decreases their drooling and improves their quality of life. Twenty children (10 males, 10 females; mean age 10y 1mo [SD 3y 8mo]; range 6y 1mo‐16y 7mo) with CP, identified as having significant daily drooling (scoring at least 6 on drooling frequency/severity scales) were recruited. BTX‐A (2U/kg; maximum 70U) was injected under sedation, using ultrasound guidance (1.4U/kg and 0.6U/kg divided between parotid and submandibular glands respectively). Nineteen children completed the study: 15 with spastic quadriplegia (Gross Motor Function Classification System [GMFCS] Level V); one with dystonia (GMFCS Level V); one with hemiplegia (GMFCS Level II); and two with a mixed pattern of CP (GMFCS Levels III and V). Drooling was assessed by five methods at baseline, and 4 and 12 weeks after injection. Qualitative assessment of drooling frequency and severity scores showed statistically significant reductions at 4 weeks (p≤0.001) and 12 weeks (p=0.006). Qualitative assessment of quality of life scores (rated by parents and teachers separately) also significantly improved (p≤0.001 and P=0.023 respectively). Quantitative assessments showed that the number of bibs/scarves changed per day was significantly reduced at 4 weeks (p≤0.001). There was no side effect from the injections themselves; 89% of parents and children wished for further intrasalivary BTX‐A injections in the future. We conclude that percutaneous intrasalivary BTX‐A injections into the parotid and submandibular salivary glands can reduce drooling in children with CP and relative sialorrhoea, leading to an improvement in their quality of life.

Parotid and submandibular botulinum toxin A injections for sialorrhoea in children with cerebral palsy

The aim of this study was to determine whether botulinum toxin A (BTX-A) injected into the parotid and submandibular salivary glands of children aged 6 to 16 years with cerebral palsy (CP) and relative sialorrhoea significantly decreases their drooling and improves their quality of life. Twenty children (10 males, 10 females; mean age 10y 1mo [SD 3y 8mo]; range 6y 1mo-16y 7mo) with CP, identified as having significant daily drooling (scoring at least 6 on drooling frequency/severity scales) were recruited. BTX-A (2U/kg; maximum 70U) was injected under sedation, using ultrasound guidance (1.4U/kg and 0.6U/kg divided between parotid and submandibular glands respectively). Nineteen children completed the study: 15 with spastic quadriplegia (Gross Motor Function Classification System [GMFCS] Level V); one with dystonia (GMFCS Level V); one with hemiplegia (GMFCS Level II); and two with a mixed pattern of CP (GMFCS Levels III and V). Drooling was assessed by five methods at baseline, and 4 and 12 weeks after injection. Qualitative assessment of drooling frequency and severity scores showed statistically significant reductions at 4 weeks (p<0.001) and 12 weeks (p=0.006). Qualitative assessment of quality of life scores (rated by parents and teachers separately) also significantly improved (p<0.001 and p=0.023 respectively). Quantitative assessments showed that the number of bibs/scarves changed per day was significantly reduced at 4 weeks (p<0.001). There was no side effect from the injections themselves; 89% of parents and children wished for further intrasalivary BTX-A injections in the future. We conclude that percutaneous intrasalivary BTX-A injections into the parotid and submandibular salivary glands can reduce drooling in children with CP and relative sialorrhoea, leading to an improvement in their quality of life.

‘Blasco replies’

Developmental Medicine & Child NeurologyVolume 45, Issue 12 p. 845-846 Free Access ‘Blasco replies’ Peter A Blasco MD, Peter A Blasco MD Child Development and Rehabilitation Center Oregon Health & Science University Portland Oregon, USASearch for more papers by this author Peter A Blasco MD, Peter A Blasco MD Child Development and Rehabilitation Center Oregon Health & Science University Portland Oregon, USASearch for more papers by this author First published: 13 February 2007 https://doi.org/10.1111/j.1469-8749.2003.tb00904.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1 Bothwell JE, Clarke K, Dooley JM, Gordon, KE. (2002) Botulinum toxin A as a treatment for excessive drooling in children. Pediatr Neurol 27: 18– 22. 2 Suskind DL, Tilton A. (2002) Clinical study of botulinum-A toxin in the treatment of sialorrhea in children with cerebral palsy. Laryngoscope 112: 73– 81. 3 Jongerius PH, Joosten F, Hoogen FJ, Gabreels FJ, Rotteveel JJ. (2003) The treatment of drooling by ultrasound-guided intraglandular injections of botulinum toxin type A into the salivary glands. Laryngoscope 113: 107– 111. 4 Stevenson RW, Allaire JH, Blasco PA. (1994) Deterioration of feeding behavior following surgical treatment of drooling. Dysphagia 9: 22– 25. Volume45, Issue12December 2003Pages 845-846 ReferencesRelatedInformation

Bilateral submandibular gland excision with parotid duct ligation for treatment of sialorrhea in children: long-term results.

Multiple procedures have been advocated for the surgical control of chronic sialorrhea in children. However, some of them are associated with significant complications or only short-term success. To evaluate the safety of bilateral submandibular gland excision (SGE) with parotid duct ligation (PDL) and to assess its long-term complications and efficacy in the treatment of chronic sialorrhea in children. Case series. Telephone interview of patients' families. Tertiary care children's hospital. Ninety-three patients with chronic sialorrhea who underwent bilateral SGE with PDL from 1988 to 1997. Operative and postoperative complications, length of postoperative hospitalization, postoperative drooling, care requirements, xerostomia, dental caries, and overall satisfaction. The mean postoperative stay was 2.4 days. There were 3 postoperative complications. Seventy-two families were interviewed (follow-up time, 1-10 years): 62 (87%) reported no further drooling or significant improvement; 7 reported the occurrence of dry mouth; and 2 reported an increase in dental caries. Bilateral SGE with PDL is a safe and consistently efficient procedure for the treatment of chronic sialorrhea in children.

Salivary gland 4-duct ligation for the management of chronic sialorrhea in children

Sialorrhea is a common and potentially debilitating problem that may arise in children with neurologic disorders, such as cerebral palsy. Excessive drooling may lead to serious quality of life problems in addition to serious life-threatening problems, ie, recurrent pneumonitis, secondary to aspiration of secretions. Numerous medical and surgical procedures have been proposed for the treatment of this problem. The technique of 4-duct ligation is described. This technique does not require external neck incisions and allows a short hospitalization with a rapid recovery time. A total of 21 patients undergoing 4-duct ligation for chronic sialorrhea reported good to excellent results, with a low complication rate. This technique is an excellent alternative to other medical and surgical options for neurologically impaired patients with chronic sialorrhea.

Clinical study of botulinum-A toxin in the treatment of sialorrhea in children with cerebral palsy.

To assess the safety and efficacy of intraglandular (parotid and submandibular) botulinum-A toxin (BTX-A) in the treatment of sialorrhea in children with cerebral palsy (CP). Prospective, open-label, dose-escalation study. Tertiary care Children's Hospital. Twenty-two subjects between 8 and 21 years of age with CP and significant sialorrhea. The first 12 subjects were injected in only the submandibular gland and the second 10 in the submandibular and parotid glands. Injections were performed under ultrasound localization. The first group (divided into 3) received a total of 10, 20, or 30 units of BTX-A. The second group (divided into 3) received a standard of 30 units in the submandibular gland and 20, 30, or 40 units in the parotid glands. Drool quantification using a pre- and postinjection "drool rating scale," dental roll weights, and "drool quotient." Swallowing was evaluated pre- and postinjection with a formal speech therapy evaluation. All subjects successfully underwent BTX-A injections without local or systemic complications. There were no adverse effects on swallowing. Objective "drool quantification" with dental rolls was extremely difficult in this population. Most indicative of results was the "drool rating" questionnaire and the "drool quotient." BTX-A is a potentially safe and promising, minimally invasive treatment for sialorrhea in children with cerebral palsy.

Long-term follow-up of submandibular duct rerouting for the treatment of sialorrhea in the pediatric population

Objective: To determine the long-term control of sialorrhea in children who underwent submandibular duct rerouting (SMDR) and to identify potential preoperative predictors of outcome. Design: Retrospective chart review of children who underwent SMDR; information updated by discussion with the permanent caregiver. Setting: Tertiary care center. Patients: Children who had significant sialorrhea resulting from a variety of neuromuscular disabilities between January 1980 and December 1995. Outcome: We report the outcome on 59 patients who underwent SMDR for the treatment of sialorrhea. Patients were ascribed a preoperative sialorrhea and global neurologic deficit score. Postoperative outcome was scored as marked, moderate, no improvement, or worse. Twenty-eight of 59 (47.4%), 28 of 59 (47.4%), and 3 of 59 (5.1%) of the patients had preoperative sialorrhea scores of 3 (profuse), 2 (moderate), and 1 (mild), respectively. Twenty of 59 (33.9%), 29 of 59 (49.2%), and 10 of 59 (16.9%) had preoperative scores of 3 (severe), 2 (moderate), and 1 (mild) neurologic impairment, respectively. Mean time to follow-up of the 59 patients was 5.46 years. Postoperative improvement scores were as follows: 50.8% had marked, 28.8% had moderate, and 20% had no to minimal improvement in their sialorrhea. Two patients were transiently worse. A complication rate of 11.3% (9 of 79) was demonstrated: 7 ranulae, 1 transient swelling of the floor of the mouth, and 1 submandibular gland infection. The preoperative global neurologic deficit score was found to be more predictive of surgical outcome than sialorrhea score. (Otolaryngol Head Neck Surg 1999;120:303-7.)

Postoperative technetium scanning in patients with submandibular duct diversion.

Submandibular duct diversion is a common procedure for refractory sialorrhea in children. The procedure reroutes Wharton's ducts from the floor of the mouth to the tongue base. As the majority of saliva in the resting state is produced by the submandibular glands, rerouting markedly decreases sialorrhea. However, the procedure has been criticized in that diversion may cause fibrosis and stricture of the ducts. The gland would atrophy, and the physiologic functions of saliva would be lost. Glandular function of six patients with cerebral palsy (mean age, 14.7 years) was evaluated by technetium scanning (mean time after surgery, 43 months). Four patients had normal bilateral function; two patients had no function in one gland but normal function in the contralateral gland. We conclude that bilateral submandibular duct diversion maintains long-term function in at least one gland.