Work-up for Salivary Stone (Sialolithiasis)
For suspected salivary gland stones, begin with ultrasound as the first-line imaging modality, which can effectively identify stones and guide immediate management decisions, particularly for submandibular gland stones which account for 80% of cases.
Initial Clinical Assessment
The diagnosis of sialolithiasis typically presents with:
- Pain and swelling of the affected gland, especially during meals when salivary flow increases 1, 2, 3
- Submandibular gland involvement in 80% of cases, followed by parotid gland 1, 4
- Palpable stone in the duct on bimanual examination (when accessible) 3
Imaging Algorithm
First-Line Imaging: Ultrasound
Ultrasound is the recommended initial imaging study for suspected sialolithiasis because it:
- Provides non-invasive, radiation-free visualization of stones 1
- Can identify stone location, size, and associated ductal dilation 1
- Works particularly well for submandibular stones, which are most common 1, 4
- Allows real-time assessment during the clinical examination 1
Second-Line Imaging Options
When ultrasound is inconclusive or for surgical planning, proceed with:
- Non-contrast CT is recommended when multiple or tiny stones are suspected, as it provides superior sensitivity for calcified stones 1
- Digital subtraction sialography remains the gold standard for visualizing subtle ductal anatomy, showing exact stone location and identifying associated ductal pathology such as stenoses 1
MR sialography is an evolving alternative that:
- Does not require ductal cannulation or contrast administration 1
- Can be performed even during acute sialadenitis when sialography is contraindicated 1
- Provides excellent soft tissue characterization 1
Imaging Considerations by Stone Size
- Stones typically measure 5-10 mm in maximum diameter 2, 4
- Stones >10 mm are considered unusually large and should be specifically reported 4
- Larger stones generally require surgical management rather than conservative therapy 2, 5, 4
Common Pitfalls to Avoid
- Do not rely on panoramic X-rays alone, as they may miss radiolucent stones or provide inadequate anatomic detail 2
- Do not attempt sialography during acute infection, as it may worsen inflammation; use MR sialography instead 1
- Do not assume small stones can always be managed conservatively without imaging confirmation of exact location and ductal anatomy 1, 3
Management Decision Points
After imaging confirmation:
- Small, accessible stones (<5 mm in the distal duct): Consider conservative management with duct milking and palliative therapy 3, 5
- Large or inaccessible stones: Surgical management is indicated 2, 3, 5
- Stones with associated ductal stenosis or chronic sialadenitis: May require gland excision rather than stone removal alone 5, 4
Sialoendoscopy is emerging as both a diagnostic and therapeutic modality, particularly useful for stones in the ductal system and may become a primary approach in the future 1.