Small calculi in wharton's sub-mandibular duct are common. Cadaveric studies suggest that 1 in 100 adults have salivary gland stones but the majority are asymptomatic.¹ The largest reported stone in the sub-mandibular duct was a 3.6cm long cylindrical calculus.² Giant salivary calculi generally require surgical removal and spontaneous passage is rare. A case of a 2cm salivary calculus which extruded without surgical intervention is presented. 

A 63 year old female presented with a 24 hour history of a constant painful swelling of the left floor of mouth, left side of the tongue and left buccal mucosa. A presumptive diagnosis of salivary stone with secondary sialadentitis was made and the patient was commenced on oral antibiotics and analgesics. The following day she presented with an extruded 2cm x 0.75cm cylindrical calculus from the sub-mandibular duct. This had been accompanied by a pustular discharge and the orifice of the duct remained swollen and inflamed. She had obtained immediate diminution of her symptoms after passing the stone and all complaints resolved during the following two days. 

The size of salivary calculi may vary from small particles to large concrements of several centimetres.² The majority are asymptomatic or cause minimal symptoms. When the calculi are large enough to impede the flow of saliva, pain and swelling are the likely presenting symptoms. Treatment with analgesics and antibiotics will reduce the surrounding inflammation and may allow salivary flow around the calculus, or permit the calculus to be washed out of the duct. Salivary calculi involve the submandibular in 92% of cases, 6% of stones occur in the parotid system and 2% in the sub-lingual or minor salivary glands.³ The seromucinous sub-mandibular gland is most susceptible for a number of reasons; the length and tortuosity of whaton's duct, the dependent position of the gland and ductal system, the ductal aperature has a smaller diameter than the ductal lumen and submandibular gland produces a higher concentration of salivary calcium than the other salivary glands.^3,4

In general practice setting, the diagnosis of a salivary stone can be made usually on history and clinical examination, including bimanual palpation of the floor of the mouth which may allow the stone to be palpated in some instances. Occlusal x-ray views of the oral cavity will allow 80% of sub-mandibular calculi and 20% of parotid calculi to be detected. Conservative management utilising oral analgesics and antibiotics is frequently adequate for resolving the acute inflammatory phase. Citrus drinks which will stimulate saliva production are advised at this stage. Sialography is useful in diagnosis as most stones do not cause complete obstruction so contrast media will demonstrate the calculus as a filling defect.⁵ This test is generally performed 4-6 weeks after the initial presentation to allow resolution of the inflammation and facilitate cannulation of the duct. The sialogram may also be therapeutic and clear out the persistent ductal debris. This management protocol is successful in the vast majority of cases.⁴ If surgery is necessary and the calculus lies in an easily accessible position simple surgical release through an incision in the floor of the mouth is the procedure of choice.⁴ When salivary calculi lie in the proximal duct or gland, sialoadenectomy may be necessary.⁶ Alternatives to surgery are extracorporeal lithotripsy and mechanical removal by sialodochoplasty using a balloon catheter.⁷ Extracorporeal lithotripsy is painless and can be repeated as required.⁷ Neither of these methods are routinely used at present in this country. The spontaneous passage of such a large sub-mandibular calculus is rare and has not be reported previously in the literature of a general practice setting.

Jeremy Cotter,
Glengarriff Medical Centre,
Glengarriff,
Co Cork

References.

1. Asfar S, Steityeh M, Abdul-Amir R. Giant salivary calculi: an orocervical fistula caused by a submandibular gland caliculus. Canadian Journal of Surgery 1989;32(4):295-6. 
2. Isacsson G, Persson NE. The gigantic salivary calculus. International Journal of Oral Surgery 1982;11(2):135-9. 
3. Batakis J. Physiology. In: Otolaryngology - Head and Neck Surgery. Cummings CW ed, St Louis: CV Mosby Co.,1986:977. 
4. Maran AGD. Non-neoplastic salivary gland disease. Scott-Brown's Otohinolargynology. 5th ed. London: Butterworths, 1987:340-50. 
5. Rice D. Diagnostic Imaging. In: Otolaryngology - Head and Neck Surgery. Cummings CW ed, St Louis: CV Mosby Co.,1986:988. 
6. McGurk M, Escudier M. Removing salivary gland stones. British Journal of Hospital Medicine 1995:54(5):184-5. 
7. Kim H, Strimling A, et al. Non-operative removal of sialoliths and scalodochosplaty of salivary duct strictures. Arch Otolaryngol Head Neck Surgery 1996;122:974-976.