Cone Beam Computed Tomography-Guided Diagnosis and Management of an Infected Two-Piece Sialolith: A Rare Case Report

INTRODUCTION

Sialolithiasis is a common disorder of the salivary glands, affecting around 0.1% to 1.0% of adults worldwide, with the majority of cases occurring in individuals aged 30 to 60 years.^[1] It is characterised by the formation of salivary calculi or sialoliths (salivary stones) within the salivary ducts.^[2] Approximately 85% of sialoliths occur in the submandibular glands; 34% of which are localised in the Wharton’s duct.^[3] Clinically, sialolithiasis manifests as swelling in the floor of the mouth due to gland enlargement, salivary retention, and reduced flow. Infected cases may show purulent discharge near the ductal orifice.^[4] Sialoliths can range in size from less than 1 mm to several centimetres. Stones larger than 15 mm in diameter are classified as giant salivary stones.^[3] The treatment for sialolithiasis depends on the size and location of the stone. Small stones can be managed with ductal massage and sialogogues, while larger stones may require shockwave lithotripsy, sialoendoscopy, or surgery.^[5] Cone beam computed tomography (CBCT) has revolutionised the diagnosis and management of sialolithiasis by providing high-resolution, three-dimensional imaging.^[6] It enables precise localisation of salivary stones, facilitates surgical planning, and minimises complications, as compared to conventional radiography techniques.^[6] The present case report highlights the essential role of CBCT in facilitating precise diagnosis and guiding a minimally invasive, staged approach to the management of a rare infected two-piece submandibular sialolith.

CASE REPORT

A 35-year-old female presented to our clinic with progressive pain that worsened after eating, along with swelling on the left side of the face in the submandibular area, which had been present for the past 4 weeks. Patient also reported that she had a history of iron-deficiency anaemia and had been on medication for 7 years. The patient had previously visited several hospitals for the swelling and was prescribed antibiotics and anti-inflammatory medications, but these did not alleviate the pain or swelling.

On inspection, there was a tender swelling in the left submandibular region, with the overlying skin appearing normal but warmer than usual. On palpation, a large, firm, tender swelling in the left floor of the mouth, near the submandibular duct, with inflamed surrounding mucosa and oozing pus discharge was noted [Figure 1].

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Figure 1:

Intraoral view of a large, firm, tender swelling in the left floor of the mouth.

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A provisional diagnosis of an infected submandibular sialolith in Wharton’s duct was made and later confirmed with CBCT scans [Figure 2]. The CBCT scans confirmed the presence of a sialolith measuring approximately 16mm x 7mm within the left submandibular gland, in the region of the lower left premolars, along with a smaller sialolith measuring 2 mm × 2 mm located posterior and inferior to the larger one. No sialography was performed because the patient presented with active infection and purulent discharge; cannulation/contrast injection in this setting can worsen ductal infection and patient discomfort. Objective sialometry (quantitative salivary flow measurement) was not performed at presentation owing to the acute presentation and local inflammation; salivary flow was assessed clinically by duct milking, and on follow-up, the patient reported restoration of normal salivary flow.

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Figure 2:

CBCT showing two submandibular sialoliths, a giant one and a smaller one posterior to it. CBCT: Cone beam computed tomography.

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CBCT-guided surgical removal of the sialolith was planned, and informed verbal and written patient consent was obtained. A series of lacrimal probes was used to locate the orientation of the Wharton’s duct. Under local anaesthesia, a mucosal incision was made lateral to the lingual frenum and medial to the sublingual fold to isolate the duct. Following isolation, a longitudinal incision was made on the duct over the stone, and sharp dissection was done to reveal the sialolith [Figure 3]. A direct cut-down was avoided to prevent the risk of ductal stenosis.

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Figure 3:

Incision made for sharp dissection to reveal the sialolith.

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The exposed sialolith was carefully detached from the surrounding tissues, taking care of the lingual nerve, and grasped with artery forceps. To prevent the stone from falling back, firm digital pressure was applied with the thumb on the duct, ensuring the sialolith was removed in a single piece. The sialolith was removed in toto, measuring 16 mm x 7 mm, with an off-white to yellowish color in appearance [Figure 4].

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Figure 4:

The surgically removed giant sialolith.

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The duct was sutured to the mucosa with 4-0 vicryl sutures only at the medial aspect to maintain the patency and to avoid injury to the sublingual gland, its ductal orifices [Figure 5]. Post-operative instructions and medications were given.

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Figure 5:

4-0 Vicryl sutures maintaining the duct patency.

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The smaller sialolith was not removed during the initial procedure due to its deeper location as seen on the CBCT [Figure 6]. The patient was prescribed vitamin C and sialagogues to stimulate gland secretion. On follow-up two days later, the patient reported pain on the left lateral border of the tongue, but the wound was healing well. The smaller sialolith was subsequently removed through the existing wound without the need for additional incisions [Figure 7]. A postoperative CBCT confirmed the removal of both stones [Figure 8].

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Figure 6:

Cone beam computed tomography showing the presence of the smaller sialolith after surgical removal of the giant sialolith.

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Figure 7:

The smaller sialolith was removed conservatively by milking the duct.

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Figure 8:

Post-operative cone beam computed tomography showing complete removal of the sialoliths.

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The suture was removed after 8 days with no post-surgical complications. Healing was satisfactory, and normal salivary flow was restored. The patient was monitored for one year, once every 3 months, with no signs of recurrence.

DISCUSSION

Submandibular gland sialoliths are common due to the submandibular duct’s wider, longer structure, antigravity flow, and higher mucin, calcium, and phosphate content.^[7] Additionally, its saliva is more alkaline than parotid saliva.^[7] Accurately diagnosing sialoliths is crucial for determining their management based on their size and location.^[8] Inspection, palpation, and milking of the ductal portion can help in the diagnostic process. Imaging exams such as occlusal radiography and CBCT scans can help visualise the sialolith with greater accuracy.^[5,6] In the present case CBCT was pivotal for four practical reasons: (1) three-dimensional localisation of both fragments and accurate measurement of the larger stone (16 × 7 mm), (2) determination of the fragment’s depth relative to the lingual cortical plate and neighbouring teeth that guided the intra-oral incision and limited exploration to reduce risk to the lingual nerve, (3) detection of the second, smaller fragment posterior and inferior to the primary calculus (2 × 2 mm) that was not clinically palpable, allowing a staged, conservative approach, and (4) post-operative confirmation of complete removal. CBCT has been shown to be highly sensitive for the detection of salivary calculi and offers multiplanar, three-dimensional reconstructions that enhance surgical planning compared with two-dimensional radiography and ultrasonography; the latter may be limited in detecting small or deep calculi or stones with low mineral content.^[9] MR sialography and sialoendoscopy, conversely, provide excellent ductal and soft-tissue detail without exposing patients to ionising radiation, though these modalities may not be readily available in all clinical settings.^[10] Imaging modality selection should therefore be tailored to availability, diagnostic need, and radiation considerations.

Treatment for sialolithiasis depends on the duration of symptoms, frequency of recurrences, and the size and location of the sialolith.^[11] It has been reported that symptomatic sialoliths must be treated with an intraoral surgical approach.^[12] However, when the sialolith is in the distal and end portion of the duct, manual milking or stimulation with lemon juice or sialogogues can be employed, which induces increased salivary secretion and favours the expulsion of the sialolith from inside the ductal lumen.^[2] This approach was used to remove the smaller sialolith located deep within the duct, bringing it closer to the surface, to be removed in the next appointment, causing minimal damage to the oral tissues. The use of CBCT in this case was instrumental not only in confirming the presence of the smaller sialolith but also in monitoring its movement within the duct, ensuring a conservative management approach.

However, a potential complication could have arisen if the stone had fractured during the procedure, necessitating further exploration, thereby increasing the risk of lingual nerve injury. This risk was attributable to the stone’s considerable size and its deep location within the duct, extending beyond the first molar. The lingual nerve typically courses medial to the first molar.^[13] Therefore, to mitigate this risk, the smaller stone was carefully removed through ductal manipulation, avoiding complications.

This case report underscores the critical role of CBCT in enhancing diagnostic precision and optimising treatment strategies for complex sialolithiasis cases. The staged approach employed by prioritising minimally invasive techniques where feasible significantly reduced the risk of complications. This approach not only preserves anatomical integrity but also promotes faster recovery and improved patient outcomes.^[8,12,14]

CONCLUSION

The successful management of this rare case of an infected two-piece submandibular sialolith reinforces the value of CBCT in guiding treatment decisions and minimising surgical morbidity. A tailored approach that balances surgical intervention with conservative techniques can enhance treatment efficacy while mitigating risks. The key takeaway from this case is that thorough preoperative 3D imaging, coupled with a strategic, patient-centered approach, is essential for achieving optimal clinical outcomes in complex sialolithiasis cases.