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Sialolithiasis - Salivary Stones - What Causes Them and How to Manage

last modified on: Thu, 02/22/2024 - 10:55

return to: Salivary SwellingSalivary Gland Surgery ProtocolsSalivary Ultrasound

see also: Combined Open and Endoscopic Removal of Parotid Stone (sialendoscopy case example) and Salivary Stone Removal with Ductoplasty from Submandibular Gland

video (with spoken audio) of procedures: Sialendoscopy with Stone Removal HOW I DO IT


  • Definition: Sialolithiasis = "Salivary stone" (see also: Salivary Swelling)
    • Sialolith (stone) composed of variable amounts of organic cellular debris, glycoproteins, and mucopolysaccharides.
    • Sialoliths (stone) also composed of variable amounts of inorganic materials calcium, magnesium, manganese, copper, iron and phosphate.
  • Prevalence / Incidence
    • Estimated 1% of the population are affected (autopsy studies) (Williams1999)
    • Incidence of 1 per 15,000 to 30,000 based on hospital admission statistics in England (Escudier 1999)
    • Incidence of 1 per 10,000 to 20,000 by personal observation by Dr. Marchal (Marchal 2003)
    • Calcifications identified by CT imaging of the parotid glands that occur in the parenchyma and are not associated with sialadenitis are not considered 'sialoliths'
      • Buch et al (2014) identified 4% of patients had incidental parotid calcifications through review of non-contrast head CT scans done on 1,571 patients for reasons other than sialadentitis 
      • Associated with the presence of calcifications were: HIV, alcoholism, chronic kidney disease, autoimmune disease and elevated alkaline phosphatase
  • Etiology - What Causes Them: Multiple Factors Considered

    • A primary process reported for parotid stones is a decrease in the salivary secretion, both volume and flow rate (Motamed 2003) due to
      • Obstruction: strictures of the duct or, external pressure on the main duct (tumor), mucus plugging, and congenital abnormalities of the duct.
      • Other: Radiation damage and immune-mediated diseases.
    • A decrease in salivary secretion results in stasis; with retrograde bacterial contamination of the ductal system.
      • Bacterial infection may lead to destruction and fibrosis of gland architecture of acinar elements and ductal ectasia.
        • Acute suppurative sialadenitis - singular acute event may precipitate others or progress to chronic sialadenitis 
        • Chronic sialadenitis is more common and often progressive
        • Sialolithiasis is both a cause and a consequence of chronic recurring sialadenitis (Travis 1977)
    • PCR study found bacterial DNA of Streptococcus genus in all examined sialoliths (Teymoortash 2002)
    • Electron microscopy identified "clear evidence of biofilm caves at the core" of each stone studied supporting a microbial etiology (acknowledging the etiology to be most likely multifactorial) (Kao 2020) 
  • Epidemiology studies
    • Tobacco smoking only positive correlation in study of nutritional habits and other behaviors (Marchal 2003)
    • No link between hypercalcemia or ingestion of hard water (Marchal 2003)
    • Katz et al (Katz 2009) suggested a genetic predisposition to form stones with 'over 300 families identified".
      • These investigators identified that in over 3500 cases of salivary lithiasis over a 20 year period, they did not identify cases wtih both submandibular and parotid stones (only one type of gland involved) - further identifying that submandidbular and parotid stones ahve the same composition but different proportions of calicum and phosphate.
  • Diagnosis
    • History of recurrent painful parotid swelling
    • Physical exam: swollen gland, palpable stone, massage of gland to produce saliva.
    • Consider blood studies to evaluate auto-immune evaluation: rheumatoid factor, ANA, SS-A, SS-B antibodies.
    • Radiographic imaging (see: Sialograms and Sialography )
      • Ultrasound: advantages - potential for concurrent U/S guided FNA; absence of radiation exposure; inexpensive
      • MRI: advantages: best study for anatomic definition of salivary glands for tumor, absence of radiation exposure; evolving technology permits 'MRI sialogram"
      • CT: controversy w or w/o contrast - currently at UIHC: employ contrast; best for defining lymphadenopathy (see: Sialolithiasis Radiology)
        • Phleboliths may be misinterpreted as sialoliths; sialendoscopy or sialogram will resolve (Su 2009a)
      • Sialogram: useful to identify stones - best definition of intraductal architecture; occasionally proves therapeutic as well as diagnostic (duct dilation, 'flushing out gland') (Gerry RG 1955)
    • Sialendoscopy


Classification of stone location (Goncalves et al 2017)

Sialolithiasis Definition:

from Goncalves et al "Sonography in Diagnosis of Sialolithiasis"

J Ultrasound Med 2017;36:2227-2235

"Hyperechoic reflexes with distal signal loss along the course of the duct"

Submandibular sonographic landmarks

Parotid sonographic landmarks

Intraparenchymal stone

proximally located in parenchyma

proximally located in parenchyma

Proximal/hilar stone

1 cm proximal to 1 cm distal to the edge of the mylohyoid muscle

1 cm proximal to the posterior edge of masseter to middle of masseter muscle

Middle third

1 cm distal to the edge of the mylohyoid muscle to the sublingual gland

middle of masseter muscle to to anterior edge of masseter

Distal duct including papillary region

from the main mass of the sublingual gland to the papilla

anterior edge of masseter muscle to papilla


Williams, M: Sialolithiasis in  pp 819 - 835 The Otolaryngology Clinics of North America  Salivary Gland Disease ed Rice DH and Eisele D Vol 32  number 5  October 1999

Marchal F, Dulgeuerov P, Becker M, Barki G, Disant F, Lehmann W. Specificity of parotid sialendoscopy. Laryngoscope 2001;111:264-71

Iro H, Waitz G, Nitsche N, Benninger J, Schneider T, Ell C.: Extracorporeal piezoelectric shock-wave lithotripsy of salivary gland stones. Laryngoscope 1992;102:492-4

Luers JC, Beutner D: Letter to the editor 'in reference to Lithotripsy for Refractory Pediatric Sialolithiasis (Laryngoscope 2009;119:298-299)  Laryngoscope 2009 August 17 epub

Su Y, Liao G, Wang L, Liang Y, Chu M, and Zheng G: Sialoliths or Phleboliths? Laryngoscope, 119:1344-7, 2009a

Walvekar RR, Carrau R, and Schaitkin B: Endoscopic sialolith removal: orientationand shape as predictors of success. American Journal of Otolaryngology. vol 30, Issue 3 Pages 153-6 (May 2009)

Su, Zu, Liao, Zheng, Cheng, Han and Shan: Salivary gland functional recovery after sialendoscopy. Laryngoscop 2009b Apr:119(4):646-52

Iro H, Zenk J, Escudier MP, Nahlieli O, Capaccio P, Katz P, Brown J, and McGurk M: Outcome of minimally invasive management of salivary calculi in 4,691 patients. Laryngoscope 2009 Feb;119(2):263-8.

Marchal F: A combined endoscopic and external approach for extraction of large stones with preservation of parotid and submandibular glands. Laryngoscope. 2007 Feb;117(2):373-7

Marchal F, Dulguerov P:Sialolithiasis management: the state of the art. Arch Otolaryngol Head Neck Surg. 2003 Sep;129(9):951-6

Escudier MP and McGurk M. Symptomatic sialoadenitis and sialolithiasis in the English population: an estimate of the cost of hospital treatment. Br. Dent J. 1999;186:463-466

Teymoortash A, Wollstein AC, Lippert BM, Peldszus R, Werner JA. Bacteria and pathogenesis of human salivary calculus. Acta Otolaryngol. 2002:122:210-214

Fritsch MH: Algorithms for Treatment of Salivary Gland obstructions Without access to Extracorporeal Lithotripsy. Otolaryngologic Clinics of North America Volume 42, Issue 6, December 2009, pages 1193-1197

Buch K, Nadgir RN, Fujita A, Tannenbaum AD, Ozonoff A, Sakai O. Clinical associations of incidentally detected parotid gland calcification on CT. Laryngoscope. 2015;125(6):1360-1365. doi:10.1002/lary.25095

Goncalves M, Schapher M, Iro H, Wuest W, Mantsopoulos K, and Koch M: Sonography in the Diagnosis of Sialolithiasis  J Ultrasound Med 2017; 36:2227-2235

Katz P, Hartl DM, Guerre A. Clinical ultrasound of the salivary glands. Otolaryngol Clin North Am. 2009 Dec;42(6):973-1000, Table of Contents. doi: 10.1016/j.otc.2009.08.009. PMID: 19962004.     (citing French article:  Katz P, Heran F. Pathologies des glandes salivaires [Salivary gland pathologies]. Encyclopedie M edico-chirurgicale (Elsevier, Masson, SAS, Paris), radiodiagnos- tic cœur-poumon 2007;32-800-A-30.)

Kao WK, Chole RA, Ogden MA. Evidence of a microbial etiology for sialoliths. Laryngoscope. 2020 Jan;130(1):69-74. doi: 10.1002/lary.27860. Epub 2019 Mar 12. PMID: 30861582.