Salivary gland stones (sialolithiasis: Treatment, symptoms, advice and help

Definition

Salivary stones represent grit blocking salivary ducts, thus preventing saliva drainage and causing gland enlargement.

Incidence/Age

Usually occurs in middle-aged adults, with a slight male preponderance.

Anatomy & Physiology

The parotid gland consists of a superficial (outer) and a deep (inner) part, which are separated by the tree-like terminal branches of the facial nerve, responsible for facial movement. Lymph nodes are present within the gland.

Saliva leaves the gland through Stensen's duct, which pierces the facial muscles and enters the mouth through the cheek opposite the second upper molar tooth. Saliva flow is stimulated by chewing and the presence of food in the mouth, particularly sour substances. The stimulus is mediated via parasympathetic nerve fibres carried on the auriculotemporal nerve to the parotid gland.

The submandibular gland consists of superficial and deep parts separated by the myelohyoid muscle. The duct leaves the deep part of the gland and enters the floor of the mouth, meeting its opposite partner. The deep part of the gland is intimately related to the hypoglossal nerve, which moves the tongue, and the lingual nerve, which provides sensation to the front half of the tongue.

Saliva flow is stimulated via parasympathetic (chorda tympani) nerve fibres carried along the lingual nerve.

80% of stones occur in the submandibular gland, with 20% occurring in the parotid gland. In most cases, multiple stones are found, but multiple gland involvement only occurs in about 3% of patients. Submandibular stones are thought to be more common because its saliva is more alkaline and has a higher concentration of calcium and phosphate, as well as a higher mucous content. Furthermore, the duct is longer and has an antigravity flow.

Causes

The cause is unknown, but stones commonly occur in patients with chronic sialoadenitis. These stones are predominantly made of calcium phosphate on an organic matrix. Gout predisposes to stones made of uric acid.

Symptoms/Signs

Recurrent pain and swelling of the involved glands is often associated with eating. Infection may occur with repeated episodes of obstruction and swelling. Stones may be palpable in the involved duct and the gland may be tender.

Complications of Disorder

Complications include acute suppurative sialoadenitis and duct narrowing (stricture).

Tests

These may include:

• Plain X-rays to identify radioopaque stones. Despite their similar chemical makeup, 90% of submandibular stones are radioopaque, but only 10% of parotid stones are radioopaque.
• Sialography, which involves injecting dye into the salivary duct openings in the mouth to identify non-radioopaque stones and strictures in the ducts, is 100% reliable in making the diagnosis if duct entry is feasible.
• Computed tomographic scanning +/- sialography

Treatment

Medical

Conservative treatments give adequate relief for many patients and include:

• Sour foods (Sialogogues) to stimulate saliva flow.
• Massaging the affected salivary gland to promote saliva flow.
• Artificial saliva products and/or frequent small drinks.
• Antibiotics are required for episodes of acute inflammation.

Surgical

Stones near the duct opening may be removed through the mouth. Stones along the length of the duct can either be removed with small endoscopes, with a basket to retrieve the stones, or can sometimes be removed by cutting down on the duct with surgical instruments. Both procedures carry the risk of scarring the duct and causing further narrowing.

Stones within the gland traditionally are treated by removing the affected gland, but can now be shattered using a li