Diagnostic Tests

Sialolithiasis (Salivary Gland Stones): diagnostic techniques

History and photographs contributed by Drs. Chad Collins and Galia Leonard, Department Oral & Maxillofacial Surgery, University of Washington.

Case History: The patient is a 54 y/o male who presented to Harborview Medical Center complaining of floor of mouth swelling over the preceding 2-3 months with increased pain around meals. The patient had High BP and NIDDM.

Besides manual palpation, most salivary gland stones have enough calcium content to be readily identified by conventional dental radiographs, especially by occlusal and panoramic (Fig 1) views. In about 80% of cases the submandibular gland stones are identifiable by the conventional dental radiographs (1). In the parotid glands, however, they are identifiable only 60% of the time. For that reason, other and more effective, but also more costly, techniques are available including computerized tomography (CT) (high resolution non-contrast CT) has been shown to be effective in identifying the salivary gland stones and other pathologies, if present (1-2). Ultrasound, sialography, and magnetic resonance imaging (MRI) have also been used (2). Ultrasound can only detect small stones, sialography requires dye injection and is therefore more invasive than CT and dental films and is contraindicated in patients with acute sialadenitis and with a history of hypersensitivity to the dye and MRI is rarely used because of its high cost compared to the other techniques.

Salivary gland stones are common in the elderly population because of the physiologic stagnation of salivary flow. Some suggest that sialolithiasis is as common as 15 cases per 1000 members of the general population (1), making it important for the general dentist to be aware of this condition and of the methods of diagnosis and treatment. It is best for the general dentist to refer these lesions to oral surgeons for treatment. It is important to diagnose sialolithiasis early because chronicity may lead to infection and degeneration of the salivary gland parenchyma. Both major (80%) and minor (20%) salivary glands are affected. The submandibular gland is the most commonly affected, bout 80-90% of cases occur in the submandibular gland (1-4), followed by the parotid gland (6-20%) and the sublingual gland (up to 2%) (1-4).

They usually present as single (Fig 2); may present as bilateral, but rarely. This condition affects adults in the fourth to the sixth decade of life with 2:1 predilection for occurrence in males (1). The submandibular gland duct is longer and more tortuous than the other ducts, therefore making it more difficult for the saliva to flow leading to stone formation and more tendency for larger size lesions to form in this area (Fig 3). The stones in this gland tend to be single and within the duct, whereas in the parotid, they are smaller, multiple and within the body of the gland (4-5). Clinically, patients complain of pain and swelling associated with eating. Sometimes swelling is the only presentation. These stones can be palpated and milked out of the orifices of the major ducts, depending on the size. Smaller stones within the duct itself can be milked out using bimanual technique. Stones can also be palpated within the minor salivary gland ducts. If a stone cannot be palpated, occlusal or panoramic radiographs should be of assistance in identifying its location.

Conservative management is the treatment of choice (4): start with recommending plenty of fluids to keep the patient hydrated, then "milk" the duct to release the stone. Stimulated salivation with lemon drops or the like should also help release the stone. If the gland is infected, antibiotics should be prescribed. If the conservative approach is not helpful, then the patient may need to undergo ductal dilatation or a minor incision of the duct to help release the stone. Removal of the entire lobe or gland is reserved for the stone that is deeply embedded in the salivary gland parenchyma.

Referrences

1. Marchal F, Dulguerov P. Sialolithiasis management: the state of the art. Arch Otolaryngol Head Neck Surg. 2003; 129: 951-956.
2. Williams MF. Sialolithiasis. Otolaryngol Clin North Am. 1999; 32: 819-834.
3. Yildirim A. A case of giant sialolith of the submandibular salivary gland. Ear Nose Throat J. 2004; 83: 360-361.
4. Baurmash HD. Submandibular salivary stones: current management modalities. J Oral Maxillofac Surg. 2004; 62: 369-378.
5. Teymoortash A, Ramaswamy A et al. Is there evidence of a sphincter system in Wharton's duct? Etiological factors related to sialolith formation. J Oral Sci. 2003; 45: 233-235.

For questions or comments, please email Dolphine Oda at doda@washington.edu