Salivary Stone (Sialolithiasis)

• Clinical Definition: Salivary stones represent mineralized calcium-phosphate deposits that cause a mechanically blocking obstruction of the salivary ducts.

• Primary Site Affected: Submandibular gland under the floor of the mouth via Wharton’s duct.

• Urgency Indicators: High grade fever, facial redness (erythema), purulent drainage from duct opening, rapidly developing swelling of the submandible with a potential risk for Ludwig’s Angina.

• Treatment Options: luid hydration/sialagogues, sialendoscopy, extracorporeal shock wave lithotripsy (ESWL), sialolithotomy, excision of the gland (sialoadenectomy).

Depending on how much a sialolith obstructs a major salivary gland duct's opening, there are two types of mechanical and/or inflammatory symptoms:

• Meal Time Syndrome: Swelling under the chin or in front of the ear occurs suddenly and is very painful at mealtimes. This happens when saliva presses on an obstructed duct when eating. 

• Palpable Sublingual Nodules: An irregularly shaped or smooth, usually hard calcification can be palpated just below the tongue along the base of the mouth.

• Xerostomia (Dry Mouth): Reduced unilateral flow of saliva leads to localized mucous membrane drying and an unpleasant sticky feeling inside your mouth.

• Ductal Orifice Erythema: Erythema (redness) is present along with focal tenderness and inflammation near the punctum of Wharton's or Stensen's ducts. 

• Bitter Taste: Intermittently purulent or infected saliva flows from the ductal orifices into the oral cavity.

Emergency or urgent visits should be made for either an evaluation of the face or throat to a maxillofacial surgeon and/or an emergency room physician if any one of the listed critical red flag conditions occur:

• Rapidly enlarging facial swelling extending toward the neck, collar bone or periorbitally

• Systemic signs of infection such as high grade fever >101.0°f / >38.3°c, chills, malaise.

• Dysphagia (swallowing difficulty) or dyspnea (breathing difficulty), due to deep space neck infections which compromise the upper airway.

• Purulent (pus) expressed through spontaneous means from the salivary ductal orifice.

• Trismus (inability to open mouth completely), due to mass effects or muscle spasms.

Sialolithiasis develops through three processes: micro-crystalline formation, and then organic and inorganic deposition onto these crystals.

• Organic debris accumulation due to salivary stagnation: When salivary flow is slowed down, there are ample opportunities for the components of saliva to aggregate and provide a focus for crystalline growth. Organic material may be mucous plugs, shed epithelial cells from salivary gland trauma or minor abrasions and even bacteria. 

• Saliva pH increase leading to calcium phosphate precipitation: The process of calcium phosphate crystal formation is greatly accelerated when the pH of the saliva increases. This is because once the ph of the saliva increases, it becomes favorable for calcium phosphate to precipitate out of solution.

• Micro-trauma of the duct: A small injury to either the ductal lumen or ductal orifice will result in localized inflammation and stricture development which will eventually lead to the accumulation of minerals.

• Reduced systemic hydration: Reduced systemic fluid levels result in increased concentrations of the electrolyte content within the saliva. This results in the precipitation of minerals at a faster rate than would normally occur.

• Dehydration & Climate: In tropical climates where humidity is consistently high throughout the year, dehydration is commonly seen. As a result, salivary flow rates become lower resulting in higher viscosities. These viscosities make it easier for minerals to accumulate and form stones.

• Diet & Lifestyle Habits: Consuming excessive amounts of calcium rich food products, using tobacco regularly and frequently (such as chewing pan/gutkha), drinking excessive amounts of alcoholic beverages. 

• Medications that Decrease Salivary Flow: Diuretic medications cause decreased fluid volume which results in decreased salivary production. Anticholinergic drugs decrease parasympathetic stimulation of salivary glands causing a decrease in salivary production. Antihistamines can also block salivary production. Psychiatric medications have been shown to affect salivary production.

• Medical Conditions: Individuals who develop gout tend to develop stones as well due to their propensity to retain urate in their tissues. Hypercalcemia (an excess level of calcium in the blood) also increases risk. Both Sjögren's disease and prior neck radiation therapy have also been associated with developing salivary gland stones.

• Demographics: Adults between 30 and 60 years old experience the highest incidence of developing stones. Males are slightly more likely to develop stones than females.

• Mirror Evaluation of Tongue Position: Stand in front of a lighted mirror. Stick your tongue to the top of your mouth. Now look at the floor of your mouth. Look for uneven red swellings or white-yellowish growths.

• Palpation (Finger Pressing): Wash your hands. Put one hand inside your mouth so it's touching the bottom part of your lower jaw. With the other hand, put two fingers under your jaw. Press upwards gently. You should be able to feel a hard "marble" like object.

• Stimulation Test: Chew a piece of lemon. Or take some fresh lime juice and squirt it on the tip of your tongue. If you experience severe sharp pain or rapid swelling near your ear or below your chin immediately, you may have an obstructive stone.

Sialolithiasis is evaluated by maxillofacial professionals based upon physical examination techniques as well as additional evaluation methods including:

• Clinical Bimanual Palpation: The tactile exploration of the ductal system in order to assess stone location and movement.

• Occlusal Intraoral Radiography: An occlusal radiograph will demonstrate many radiopaque submandibular stones but there are about 20% of those submandibular and about 50% of all parotid stones which are radiolucent and therefore cannot be identified using basic X-rays.

• Ultrasonography (USG): A non-invasive primary imaging modality used to map stone size, acoustic shadowing, and parenchymal tissue inflammation.

• High-Resolution CT Without Contrast: Used as a reference study for identification of small stones located within the gland itself, as well as detection of multiple stones.

• Diagnostic Sialendoscopy: Insertion of a micro-endoscope (size 0.8-1.3mm) into the ductal system to allow for real time visualization of the lumen.

Beginning with the clinical presentation and severity level, these can be divided based on the patient’s symptoms and stone size.

• Conservative therapy is used to treat patients who have had their first occurrence of sialolithiasis. It works by stimulating saliva production to assist in clearing the sialolith from the gland. This method is considered the first line because it does not require surgery or general anesthesia. However, if conservative therapy fails or cannot be continued, other treatments will need to be initiated.

• Sialendoscopy & Micro Basket Retrieval: This procedure allows for visualization of the duct system and extraction of stones via micro-baskets or forceps. No external incision is required. Patients are typically treated in an outpatient setting under local anesthesia or general anesthesia. 

• Extracorporeal Shock Wave Lithotripsy (ESWL): High-intensity shock wave lithotripsy breaks down large stones into fragments that can pass spontaneously or can be easily retrieved by sialendoscopy.

• USG (ultrasound) and Diagnostic Consultation: ₹1500 to ₹3500;
   

• CT Scan : ₹3500 to ₹7000;

• Outpatient Medical Management or Conservative Treatment of Minor Salivary Gland Problems: ₹1000 to ₹2500.

• Diagnostic and Therapeutic Retrieval Using Sialendoscopy: ₹35,000 to ₹75,000.

• Surgical Removal of a Salivary Stone via Transoral Sialolithotomy: ₹20000 to ₹45000.

• Open Surgical Sialoadenectomy: ₹55,000 to ₹1,20,000.
   

Major private health insurers and government health programs will usually provide coverage for in-hospital procedures including diagnostic imaging and also outpatient procedures involving general anesthesia.

• General Dentist Practitioner: Screens patients initially for sialadenitis, provides hydration protocols conservatively and prescribes antibiotics for mild cases.

• Oral/Maxillofacial surgeon (OMFS): Provides core expertise on transoral sialolithotomy and sialendoscopy along with all reconstructive options for structural defects as well as submandibular gland excisions.

• Otolaryngologist (ENT): Has specialized experience in performing micro-endoscopic evaluations of salivary glands and has skills in differentiating head and neck tumors, as well as providing surgical expertise in removing parotid tissue.

• Immediate (within 2-4 hours): Rapidly spreading facial swelling that extends toward the neck, high-grade fever, dysphagia (difficulty swallowing) or dyspnea (difficulty breathing) caused by deep space neck infections compromising the airway. 

• Urgent (24-48 hours): Localized persistent pain or pus actively draining from a single duct opening or inability to consume solid food at meals due to constant swelling in the lower front portion of the face.

• Elective (1-2 weeks): Firmness on the underside of the jaw during eating which resolves once you finish eating or an incidentally discovered sublingually located rock-hard nodule.

1. Why only when I have eaten traditionally spicy or sour foods does my jaw begin to swell? 

Traditional spicy and sour foods are considered very strong sialagogues which stimulate all of your salivary glands to quickly release large amounts of fluid/saliva into your mouth. When there is a blockage by a stone in the duct, this causes rapid distension of the gland and therefore causes severe, immediate pain.

2. Can salivary stones be dissolved with no need for surgical intervention simply by consuming water and/or making dietary changes? 

Stones that are made entirely of calcium phosphate will not dissolve with water alone or through diet changes. However, if a stone is relatively small (less than 3 mm), it may be able to pass on its own with heavy drinking of water combined with manually massaging the affected gland while also stimulating it through use of sialagogues.

3. Will having your submandibular gland removed result in xerostomia (dry mouth)? 

No. Humans possess three paired major salivary glands (submandibular, parotid, sublingual) alongside hundreds of microscopic minor glands. Removal of a single major salivary gland results in increased function of the other glands so there is no long term reduction in oral moisture.

• Sialadenitis (bacterial infection): Acute or chronic bacterial infection in salivary gland tissue secondary to prolonged ductal stasis.

• Ductal stricture (scarring / narrowing): Chronic scarring and narrowing of the salivary duct lumen from repeated infections or chronic calculus trauma.

• Ranula (mucous cyst): A mucous extravasation cyst on the floor of the mouth resulting from a disruption of the sublingual or submandibular duct.

• Sialodochoplasty: The surgical reconstruction of the duct orifice to establish a wide, persistent opening for recurrent stone prevention.

• Antibiotics & Anti-inflammatory Post-op: Targeted antibiotics & anti-inflammatories post-operatively to eliminate residual bacteria and reduce inflammation of the gland.

• Counseling for Habit Modification & Daily Electrolytes: Preventive counseling tailored to promote daily electrolyte ingestion, tobacco abstinence and good oral hygiene practices.

Obstructive salivary gland dysfunction due to sialolithiasis continues to be a leading cause of obstructive salivary gland dysfunction world-wide. The shift toward preserving the function of the salivary glands has led to modern management strategies for salivary gland obstruction, shifting away from traditional open surgical gland excisions to gland-preserving methods including diagnostic & therapeutic sialendoscopy. High resolution ultrasonography is capable of providing early diagnosis of obstructive salivary gland dysfunction thereby preventing chronic parenchymal destruction as well as deep space infections of the neck. All patients experiencing recurrent swelling during meals should seek early evaluation by a specialist to prevent scarring or destruction of their native salivary gland anatomy.