Drooling (Sialorrhea)

Because of the associated cerebral palsy, drooling causes functional, social, psychological, and clinical burdens on patients, their families, and caregivers.

Patients who drool often experience repeated perioral skin breakdown and infections. Clothing and bibs become soiled and need frequent changing, which can become very laborious and limit the family's ability to be active and out of the home. In addition, teaching materials and communicative devices may become wet and damaged, impairing educational efforts. In severe cases of drooling, dehydration may even become a problem. Social embarrassment may make it difficult for patients who drool to interact with their peers and can lead to isolation.

Posterior drooling, however, causes congested breathing, coughing, gagging, vomiting, and, at times, aspiration into the trachea that results in recurrent pneumonia.[1]

Because the lifespan of cerebral palsy patients is often shortened, more than 85% of patients with problems controlling drooling are younger than 21 years.

Frequency

The actual prevalence rate for patients who drool is unknown. However, 0.5-0.7% of all children born are diagnosed with cerebral palsy. From 10-37% of patients with cerebral palsy have been reported to have difficulty with drooling because of neurologic impairment. Reportedly, 10% of Swedish, 37% of Belgian, and 13% of Indian children with cerebral palsy have severe drooling. However, this is not an affliction that is particular to any specific ethnic background. Most of the patients requiring help for drooling belong to this group.

Drooling may be a result of hypersecretion (primary sialorrhea) of the salivary glands but is more commonly due to impaired neuromuscular control with dysfunctional voluntary oral motor activity that leads to an overflow of saliva from the mouth (secondary sialorrhea). Patients often have inefficient and infrequent swallowing, which further compounds the problem. Furthermore, problems with positioning due to poor head control and decreased neck strength magnify the effects. An enlarged tongue or tongue thrusting with poor control can contribute to the problem of drooling. Finally, dental caries and infection and diseased gingival tissues with gingivitis can markedly increase drooling.

The salivary glands secrete an average of 1-1.5 L of saliva per day. The 3 groups of major paired salivary glands, the submandibular, sublingual, and parotid glands, along with the minor salivary glands located throughout the surface of the palate, tongue, and oral mucosa, secrete saliva. The submandibular gland produces 70% of resting secretions. The 20% from the parotid glands is a result of external stimuli such as food. The remaining 10% of saliva secreted is from the sublingual and remaining minor salivary glands. Saliva serves many functions. It protects the teeth and gingival tissues from infection, lubricates the oral mucosa to aid in swallowing and speech, deters foul breath by cleansing the oral cavity, and promotes digestion by breaking down proteins and carbohydrates with amylase.

The secretory control of the salivary glands is mostly parasympathetic. Innervation of the parotid gland is from the salivary nucleus via the glossopharyngeal nerve, the tympanic plexus in the middle ear, the otic ganglion, and the auriculotemporal nerve. The submandibular and sublingual glands receive fibers carried by the facial nerve and chorda tympani, which originate in the superior salivatory nucleus.

Hypersecretion is a rare cause of drooling. Most often, this occurs as an adverse effect of medications such as some tranquilizers, anticonvulsants, and anticholinesterases that increase activity at the muscarinic receptors of the secretomotor pathway and result in hypersecretion.

Any impairment of the oral phase of deglutition secondary to neuromuscular disorders, trauma, surgical resection, or facial nerve paralysis can result in spillage of saliva from the oral cavity. Most patients who drool have impaired oral neuromuscular control due to cerebral palsy or severe mental retardation.

History

A thorough history is invaluable prior to treatment. Make an assessment of the severity and frequency of drooling, and inquire about the effect on the quality of life for the patient and family. Importantly, identify factors contributing to drooling. Caregivers or parents can assist in assessing the characteristics of drooling, such as peak time of day, changes in volume with specific activities, consistency of saliva (ie, thick, mucinous, watery), and the frequency of drooling.

Quantitative measurements can be difficult, but classification schemes for drooling have been developed to give a general idea of the magnitude of the problem. Multiple classification schemes have been used by different authors to report the severity of drooling.

The severity of drooling can be classified with the following scale:

• Dry - Never drools

• Mild - Only lips wet

• Moderate - Lips and chin wet

• Severe - Clothing soiled

• Profuse - Clothing, hands, and tray moist and wet

The frequency of drooling can be quantitated based on the following scale:

• Never drools

• Occasional drooling - Not every day

• Frequent drooling - Every day

• Constant drooling

These types of classifications can be helpful for guiding treatment decisions and for preoperative and postoperative comparisons to determine the outcome of surgery. They can also be helpful for reporting purposes to compare results of techniques between institutions.

Some specific points to address when assessing the magnitude of the problem with caregivers include the following:

• Number of bib or clothing changes per day

• Difficulties with keyboards or other communication devices

• Severity of perioral skin maceration and infections.

The system used by Wilkie and Brody to classify the results of drooling procedures is as follows:

• Excellent - Normal salivary control

• Good - Slight loss of saliva with or without dried froth on the lips

• Fair - Improved, but with significant residual saliva loss or with thickened, offensive, brown, gummy froth

• Poor - Failure to control or too dry

Other clinical factors that could contribute to drooling and spillage of oral contents should be explored while taking the patient's history. Nasal obstruction with chronic mouth breathing can exacerbate drooling. The most common cause of obstruction is adenoid hypertrophy, but consider anterior obstruction of the nose due to other causes, such as allergic rhinitis. Malocclusion, gingivitis, and dental caries can contribute to drooling and should be addressed by a pediatric dentist at the outset of the evaluation.

Physical examination

Perform a thorough head and neck examination. Give special consideration to those anatomic factors that could contribute to or exacerbate drooling so that these issues can be addressed prior to surgical intervention. Some key points to evaluate during the physical examination include the following:

• Head position and control

• Condition of perioral skin

• Tongue size and control and the presence of thrusting behaviors

• Tonsil and adenoid size

• Occlusion: Malocclusion, particularly an open bite deformity, is a common finding in patients with cerebral palsy. This can make proper oral hygiene very difficult. Open bite deformities can prohibit closing of the mouth and can mimic nasal obstruction in these patients.

• Dentition: Caries may be noted.

• Gingival tissues

• Mandible and palatal position

• Gag reflex and intraoral tactile sensitivity

• Presence of mouth breathing

• Nasal obstruction and the appearance of tissues upon anterior rhinoscopy

• Swallowing efficiency: Determine this by observation, barium swallow, or fiberoptic endoscopic evaluation of swallowing.

• Neurologic examination: Pay particular attention to cranial nerve examination findings.

Indications for surgery include (1) persistent drooling following at least 6 months of conservative therapy and (2) moderate to profuse drooling in a patient whose cognitive function precludes participation with conservative oral and physical therapy.

Parasympathetic innervation of the parotid gland is from the inferior salivary nucleus via the glossopharyngeal nerve, the tympanic plexus on the medial wall of the middle ear, the lesser superficial petrosal nerve, the otic ganglion, and the auriculotemporal nerve. The submandibular and sublingual glands are innervated by fibers from the superior salivary nucleus via the facial nerve, chorda tympani in the middle ear, lingual nerve, and submandibular ganglion.

1. Patients at high risk for surgery because of other medical concerns.

2. Tympanic neurectomy and chorda tympani nerve sections are contraindicated in patients with unilateral hearing loss because of the small risk of hearing loss associated with these procedures.

3. Posterior rerouting of the submandibular or parotid ducts is controversial in patients who have difficulties with chronic aspiration due to their neurologic status. Associated conditions may include esophageal motility disorders, esophageal spasm, or aspiration. Some authors believe this procedure puts the patient at increased risk of aspiration because of the increased burden of secretions in the hypopharynx. Other authors have demonstrated no increased difficulty with aspiration in this patient population.

4. In patients with athetoid disorders with constant tongue thrusting, surgical procedures to correct drooling may result in an unpleasant, thick, discolored, malodorous residue being deposited on the teeth and lips. This may prove to be more offensive than the constant, watery drooling.

See the list below:

• Salivary flow rate (mL/min) - Increase in weight of dental rolls/time of collection

  • The absorbent dental rolls can be kept directly at the orifices of large salivary glands

• Drooling Quotient - 40 observations in 10 minutes (every 15 minutes)

  • DQ% = 100 x number of drooling episodes/40

• Teacher Drooling Scale - 1-5

  • 1= no drooling

  • 3= occasional drooling

  • 5= constantly wet saliva leaking on clothes and furniture

See the list below:

• Lateral neck film: Adenoid hypertrophy can be confirmed if the patient has a history of nasal obstruction. Complete the adenoidectomy prior to further surgical intervention to neutralize the effects of mouth breathing on drooling.

• Modified barium swallow: Some authors recommend performing this study to help rule out the contraindications to surgical therapy, including esophageal motility disorders, esophageal spasm, and aspiration.

• Radiosialography: For some authors and for research purposes, these scans using radioisotope are useful for evaluating the secretory function of the salivary gland when assessing the success of surgical therapy.

See the list below:

• Audiogram: Perform this study on patients being considered for tympanic neurectomy or chorda tympani nerve section, because unilateral hearing impairment is a contraindication (owing to the risk of hearing loss associated with the procedures).

• Flexible nasopharyngoscopy: This is an alternative method of assessing the amount of adenoid tissue if the patient has history findings suggestive of nasal obstruction.

Treatment of patients with drooling problems has been successful at some centers using a team approach, including an otolaryngologist, pediatric dentist, speech pathologist, and physical therapist.[2]

Aggressive physical medicine or medical management prior to considering surgical intervention is recommended. Medical management is directed towards correcting the oral motor dysfunction and decreasing the secretory volume of salivary glands.

Oral motor training

Patients with cerebral palsy are often affected by varying degrees of physical disability, including lack of muscle tone affecting head position and oral dysfunction, which causes the initiation of swallowing to be uncoordinated and inefficient. Exercises are used to attempt to normalize muscle tone, stabilize body and head position, promote jaw stability and lip closure, decrease tongue thrust, increase oral sensation, and promote swallowing. The speech pathologist, physical therapist, and occupational therapist administer this arm of medical therapy.

Oral motor training is time consuming. The therapy requires a minimal level of cognitive function and motivation on the part of the patient and caregiver.

Very few data are available to confirm the effectiveness of these therapies. However, because of the noninvasive nature and the varied response of individual patients, all patients capable of this therapy should undergo at least a 6-month trial of oral motor training.[3]

Behavioral therapy

Verbal and auditory cues are used to attempt to increase the frequency and efficiency of swallowing. Several methods, including reward, overcorrection, and punishment, are used by caregivers to initiate swallowing. External devices that deliver timed auditory cues to swallow are also used.

Several authors note that the success of therapy is dependent on the patient's cognitive level of function and ability to concentrate. Hence, patient-to-patient variability of results is considerable. Also, success is variable according to the task being completed by the individual patient when the cue is delivered. Consequently, extrapolation of results to patients' daily environments is difficult. Regression of therapy has been shown to occur at varying times following training sessions. Repeat therapy is often required.

Pharmacologic therapy

Anticholinergics

The use of anticholinergics to inhibit activation at muscarinic receptors, at best, decreases the volume of drooling. The doses tolerated have not caused drooling to completely cease.

Adverse effects experienced secondary to the lack of selectivity of the muscarinic receptors affected often limit treatment. Adverse effects include irritability, restlessness, sedation, and delirium from central effects of the drugs. Also, the inhibition of sweat glands has caused significant inhibition of temperature regulation. Inhibition of GI motility has resulted in worsening constipation in a population already plagued with such difficulties. Photophobia, urinary retention, and facial flushing also result from these medications.

Transdermal scopolamine has been used with success for short periods. No data illustrate its efficacy over longer periods.

A double-blind trial illustrated a 50% decrease in drooling with the administration of benztropine in adults. However, the results varied significantly in the study that included a pediatric population. Glycopyrrolate was also shown to decrease drooling in 95% of patients.[4] However, 30% of patients in this unblinded study discontinued treatment because of adverse medication effects.

Botulinum toxin 

RimabotulinumtoxinB (Myobloc) gained approval from the US Food and Drug Administration (FDA) in August 2019 for treatment of chronic sialorrhea in adults. Approval was based on evidence from two randomized trials. In one study, 187 patients were randomized to rimabotulinumtoxinB or placebo. Compared with placebo, significant improvement was seen in the rimabotulinumtoxinB group from baseline to week 4, as measured by the unstimulated salivary flow rate (USFR) and Clinical Global Impression of Change (CGI-C) scores.[5, 6] The second trial confirmed these results during dose escalation and follow-up for 20 weeks after injection.[6]

The botulinum toxin incobotulinumtoxinA (Xeomin) was approved by the FDA in July 2018 for the treatment of chronic sialorrhea. Approval was based on the SIAXI (Sialorrhea In Adults Xeomin Investigation) clinical trial, which involved adults (n=184) with chronic, troublesome sialorrhea related to Parkinson disease; atypical Parkinson syndromes; stroke; or traumatic brain injury. Patients underwent a single treatment with incobotulinumtoxinA or placebo, via four injections (administered bilaterally into the parotid and submandibular salivary glands); the total dose of botulinum toxin injected was either 75 U or 100 U. The drug proved more effective than placebo at 16-week follow-up, with the greatest improvement seen in patients who received the 100 U dose.[7]

Botulinum toxin is an exotoxin produced by the bacterium Clostridium botulinum, a gram-positive, anaerobic bacillus.[8, 9] Botulinum toxin type A is one of 8 distinct known neurotoxins, each with its own immunologic specificity.[9] It leads to partial or complete muscle paralysis by inhibiting acetylcholine release at the neuromuscular synaptic end plate.[10, 11, 12]

This toxin also blocks the release of acetylcholine at the cholinergic synapses of the autonomic nervous system; thus, this toxin can block cholinergic parasympathetic secretomotor fibers of the salivary gland. Hence, botulinum toxin has been tested in some autonomic disease, such as achalasia, hyperhidrosis and gustatory sweating (Frey syndrome).[13] Lim and Choi (2008) have reported that injection of botulinum toxin type A is a highly effective and relatively safe primary method of treatment for an acute postparotidectomy salivary fistula that, if treated with conventional pressure dressings, takes long to subside.[14]

Botulinum toxin type A can be injected into the parotid gland, but better results are obtained when it is injected into both the parotid and submandibular glands. In a study on 5 patients between ages 45-59 years with amyotrophic lateral sclerosis, botulinum toxin application was guided by ultrasonography and injected in doses of 30 U in one point for submandibular gland and 20 U in 2 points for each parotid gland, after topic anesthetic with prilocaine. The symptoms of sialorrhea were observed to change dramatically in 4 patients. Three patients were treated for almost 4 months without experiencing repercussion in their quality of life. No patient presented local or systemic effects with local injection of BOTOX®.[15]

In another study, by Costa et al, botulinum toxin type B injections in the parotid (1000 U) and submandibular (250 U) glands using anatomic landmarks were found to be effective and safe in treating sialorrhea (drooling) in bulbar-onset ALS.[16] Marina et al showed that the use of ultrasonography in injecting botulinum reduces the risks of complications.[17]

A study by Barbero et al indicated that ultrasonography-guided botulinum toxin type A injections have long-term efficacy in the treatment of sialorrhea. The study involved 38 adult patients with sialorrhea who received bilateral, ultrasonography-guided botulinum toxin injections in the parotid and submandibular glands. The investigators found a mean efficacy period of 5.6 months for the treatment, as determined through decreases in the frequency of daily aspirations and through patient and caregiver improvement reports.[18]

Similarly, a study by Lungren et al indicated that refractory sialorrhea in children can successfully be treated with ultrasonographically guided, weight-based salivary gland injections of botulinum toxin type A. The study, which involved 111 patients with refractory sialorrhea, including those whose condition was caused by cerebral palsy (29%), encephalopathy (5%), anoxic brain injury (4%), or chromosomal anomaly (5%), found that the treatment had an overall effectiveness rate of 68%. No major complications occurred, with minor complications arising in less than 2% of patients.[19]

A study by Petracca et al found that ultrasonography-guided injections of either botulinum toxin type A or B produced long-term beneficial effects in cases of severe sialorrhea. The study, which involved 65 patients with either amyotrophic lateral sclerosis (ALS) or Parkinson disease, reported a mean treatment benefit period of 87 days, with the duration similar for both toxin types. However, the efficacy period was significantly longer in patients with Parkinson disease than in those with ALS and was also longer in older-age patients.[20]

Radiotherapy

Radiation delivery to the major salivary glands has been used in an attempt to decrease the rate of saliva secretion.[21] Because of the risk of late malignancy in the irradiated field, it should be used judiciously. Neppelberg et al (2007) found that single-dose radiotherapy (7.5 Gy) significantly reduces sialorrhea and is an effective and safe palliative treatment in patients with ALS and is more effective than botulinum in these cases.[22] Postma et al 2007 concluded that a bilateral dose of 12 Gy can be given to the parotid and part of the submandibular glands and is useful in patients with parkinsonism.[23]

Similarly, a randomized, double-blind, placebo-controlled study by Steenbakkers et al indicated that irradiation of the submandibular or parotid glands can reduce drooling in patients with parkinsonism. The investigators found that radiotherapy to either type of gland was equally effective, although at 6-month follow-up, 33.33% of patients in the submandibular group reported sticky saliva as an adverse treatment effect, versus 13.33% of the parotid group.[24]

In most cases, surgical intervention should be instituted following the failure of at least 6 months of more conservative therapy. Surgery is best delayed until the patient is aged 6 years or older in order to allow time for complete maturation of oral motor function and coordination.

Procedures to control drooling fall into 2 main categories directed at decreasing salivary flow or redirecting the flow to a more advantageous location to promote swallowing. Multiple combinations of these procedures have been studied by various authors and have been shown to have advantages and disadvantages.

Three surgical approaches by an otologist can help to decrease salivary flow, including removal of the salivary glands, ligation of the salivary ducts, and sectioning of the nerves in the middle ear, which are responsible for salivary production. Most commonly, gland excision involves the submandibular glands. A large percentage of resting salivary production comes from the submandibular glands, and their excision is a common procedure performed by otolaryngologists, with minimal morbidity and risk. The sublingual glands make only a very small contribution to the volume of saliva, and parotid gland excision is a more hazardous procedure associated with greater risk.

Transtympanic neurectomy to reduce salivary flow

In this procedure, the parasympathetic nerve supply to the parotid, submandibular, and sublingual glands is interrupted as the nerves traverse the middle ear along the medial wall. A transtympanic approach is completed by elevating a tympanomeatal flap and transecting the nerves of the tympanic plexus on the promontory and the chorda tympani as they pass the handle of the malleus. This procedure is technically simple, has little associated morbidity, and has a short recovery time. An initial success rate of 50-80% can be expected, with a high incidence of late failures secondary to regeneration of the nerve fibers. This procedure may be used to complement another drooling procedure or after other procedures fail to control drooling.

Sectioning the bilateral chorda tympani nerves has the expected outcome of loss of taste to the anterior two thirds of the tongue. This can have a significant impact on quality of life and must be carefully considered with the patient and family prior to proceeding.

Excision of submandibular glands with bilateral parotid duct ligation to reduce salivary flow

For many years, the Wilkie procedure of excising the bilateral submandibular glands and rerouting the parotid ducts to the tonsillar fossa was the mainstay of surgery for drooling patients. Because of associated postoperative morbidity and complications, authors have continued to pursue modifications of this procedure. Submandibular excision with parotid duct ligation is technically less challenging and is associated with less overall morbidity and a shorter hospital stay.

This procedure has been reported to have an 85-100% success rate. Shott et al reported cessation of drooling in 21 of the 24 patients in their series who underwent these 2 procedures in combination.[25] They reported their highest success with long-term management of drooling compared with other procedures. In their review, they also compared results of submandibular duct rerouting and bilateral tympanic neurectomy in various combinations. This has become one of the most popular current techniques used for control of drooling. It has several advantages, including technical ease and lack of postoperative morbidity. The hospital stay is usually approximately 3 days. Submandibular gland excision avoids the complication of floor of the mouth edema observed with duct rerouting procedures. The external scars and temporary mild facial swelling after surgery are the most significant drawbacks to the procedure. Parotid duct ligation is a quick procedure and does not put the facial nerve at risk.

Parotid duct ligation involves locating the papilla across from the upper second molar. The papilla is cannulated with a lacrimal probe, and 1-2 cm of duct length is dissected. The duct is then ligated with a suture and resected. The mucosa can be closed primarily. Submandibular gland excision is a familiar procedure to all otolaryngologists. Very briefly, it involves incisions parallel to the mandible. The gland is excised in a subcapsular plane, and care is taken to avoid injury to the marginal mandibular, lingual, and hypoglossal nerves. The wound is typically closed in a subcuticular fashion without a drain.

Procedures to Redirect Salivary Flow

Rerouting procedures have the positive effect of preserving salivary production and taste.

Bilateral transposition of the submandibular ducts is the most commonly performed surgical procedure for drooling in many centers. The procedure is accomplished by making a rhombus-shaped incision in the mucosa, including the 2 ductal openings within, and then separating the 2 openings with an incision in the middle so as to provide a mucosal cuff around each ductal opening. The ducts are thereafter dissected for a length of 3-4 cm, usually until the lingual nerve is seen crossing the duct. A submucosal tunnel is then developed between the incision and the tonsillar fossa just behind the anterior pillar. The ducts are then passed posteriorly in the submucosal plane, and the mucosal islands are secured with 2-3 sutures. Bilateral submandibular duct transposition can be carried out in most cases without prior tonsillectomy, and the duct can be transposed on the tongue just behind the medial edge of the anterior pillar (see the following images).

Alternatively, some authors advocate transposing the ducts to a location at the base of the anterior pillar. This is thought to eliminate the need for tonsillectomy in a patient with large tonsils and also reduces the risk of infection of the duct secondary to tonsillar infection. The success rate reported in the literature is 80-100%. Many authors advocate sublingual gland excision at the time of the primary procedure to prevent ranula formation, which is a frequent complication of this procedure.

Submandibular duct rerouting in combination with tympanic neurectomy has a reported success rate of approximately 75%. Parotid duct rerouting has been a popular procedure in the past but has been associated with a significant amount of postoperative facial swelling and morbidity. It is performed in a fashion similar to submandibular duct rerouting, with mucosal islands formed around the Stensen duct and submucosal tunnels used to pass the ducts posteriorly. The buccal incision is closed primarily. This procedure combined with submandibular duct excision was first described by Wilkie in 1967 and was subsequently referred to as the Wilkie procedure.[26] In recent years, this procedure has been abandoned by most authors in favor of parotid duct ligation, which results in much less postoperative facial swelling and is technically very simple.

Submandibular duct ligation

In a study of patients with nonprogressive neurodisabilities, Bekkers et al found that two-duct ligation, which involved clipping the submandibular ducts, significantly reduced drooling, as subjectively apprised over a 1- to 12-year period. Nonetheless, there was some recurrence of drooling over the follow-up period, and subsequent treatment was required for 33.3% of patients, in whom the ligation was not sufficiently effective.[27]

After most drooling procedures, intravenous hydration is necessary until intake is adequate. Patients or caregivers are given proper instruction on appropriate wound care (when indicated) and adequate oral hygiene using medicated rinses.

Tympanic neurectomy and chorda tympani nerve sections are outpatient procedures that require similar postoperative care to other minor otologic procedures. The patients' ears must be kept dry. Antibiotic drops may be used.

Submandibular gland transposition can lead to significant postoperative floor of the mouth edema. Continued intubation for the first 24-48 hours postoperatively may be necessary if this becomes a significant airway concern. In most circumstances, this is not necessary, and the average hospital stay is 3-5 days. Perioperative antibiotics are used for 7-10 days.

Submandibular gland excision with bilateral parotid duct ligation commonly causes transient cheek swelling. This is not to the extent seen with submandibular rerouting procedures that require floor of the mouth dissection. The average hospital stay is 3-5 days.

Patients undergoing tympanic neurectomy have no diet restriction. Patients undergoing submandibular gland duct transposition and submandibular gland excision with bilateral parotid duct ligation normally remain on intravenous fluids for approximately 24 hours or until adequate intake is tolerated. Postoperative antibiotics are continued for 7-10 days, and pain medication is prescribed as needed.

A soft diet is tolerated very well by most patients within the first 48 hours and should be maintained for the first postoperative week in any patient with an intraoral incision.

Further inpatient care

Airway monitoring is often necessary because of the immediate postoperative swelling associated with submandibular gland rerouting. This risk is higher in children with associated craniofacial abnormalities or those with preexisting airway concerns.

Further outpatient care

Patients may continue to benefit from behavioral or pharmacological intervention in addition to surgical treatment. More commonly, this is no longer necessary. Sometimes, surgery is offered as a staged procedure. Patients and families are counseled that a second procedure can be added at a later date if the patient does not have adequate control of symptoms with the first surgery.

Tympanic neurectomy

Complications may include hearing loss, tympanic membrane perforation, otitis media, and cholesteatoma. Additionally, xerostomia is reported.

The incidence of otologic complications associated with tympanic neurectomy mirrors that of most otologic procedures using a transcanal approach. The risk of these complications is not increased with the completion of tympanic neurectomy.

Recurrence of drooling has been seen within 6 months. It is attributed to regeneration of the nerve fibers of the chorda tympani and tympanic plexus.

Loss of taste in the anterior two thirds of the tongue is an expected and unavoidable adverse effect of sectioning the bilateral chorda tympani nerves; however, most authors believe this is a cruel and unacceptable result in a patient population in which taste may be one of the few simple pleasures.

Submandibular gland duct rerouting

Floor of the mouth edema is a reported complication of this procedure. Others include duct obstruction, lateral cervical cyst formation, and sialadenitis.

Ranula formation is a common problem, occurring in as many as 10% of patients in some studies. This is secondary to interruption of the sublingual ducts as they empty into the submandibular duct. Some authors advocate sublingual gland excision in combination with this procedure in order to avoid ranula formation.

Submandibular gland excision and parotid gland duct ligation

Complications may include parotid gland swelling, marginal mandibular nerve injury with a resultant increase in problems with oral sphincter control, hypoglossal nerve injury, lingual nerve injury, xerostomia, and transient facial swelling.

Additionally, dental caries are a reported complication with this procedure. An increase in dental caries can be associated with any procedure that decreases the volume of saliva. An initial evaluation and close follow-up with a pediatric dentist is a necessity in patients considering this surgery.

Parotid duct rerouting

Complications include parotitis, fistula formation, dental caries, gingivitis, and cyst formation.

Anticholinergic agents inhibit activation at muscarinic receptors, and at best, decrease the volume of drooling. At tolerable anticholinergic doses, drooling is unlikely to completely cease.

Botulinum toxin leads to partial or complete muscle paralysis by inhibiting acetylcholine release at the neuromuscular synaptic end plate. It also blocks the release of acetylcholine at the cholinergic synapses of the autonomic nervous system; thus, this toxin can block cholinergic parasympathetic secretomotor fibers of the salivary gland. IncobotulinumtoxinA has received FDA approval for the treatment of chronic sialorrhea.

Class Summary

Injection of incobotulinumtoxinA or rimabotulinumtoxinB into the parotid and submandibular glands has been approved by the FDA for adults with chronic sialorrhea owing to various neurologic disorders, including Parkinson disease, amyotrophic lateral sclerosis, cerebral palsy, and stroke.

IncobotulinumtoxinA (Xeomin)

Through inhibition of acetylcholine release from peripheral cholinergic nerve endings, incobotulinumtoxinA deters cholinergic transmission at the neuromuscular junction. It is indicated for adults with chronic sialorrhea.

RimabotulinumtoxinB (Myobloc)

Through inhibition of acetylcholine release from peripheral cholinergic nerve terminals, rimabolutinumtoxinB deters cholinergic transmission at the neuromuscular and salivary neuroglandular junction. It is indicated for treatment of chronic sialorrhea in adults.