Possible etiology of calculi formation in salivary glands: biophysical analysis of calculus

Intraoral Microscopic Versus Robot-Assisted Sialolithotomy and Sialendoscopy for Submandibular Stones

OBJECTIVE

Sialendoscopy has remained the standard of treatment for sialolithiasis; however, large stones impacted in the submandibular gland hilum often require an intra-oral combined approach.

METHODS

Patients treated for submandibular hilar sialolithiasis from 2015 to 2021 at two tertiary centers were stratified into two groups based on the surgical technique: Intraoral Microscopic-Assisted Sialolithotomy (IMAS) versus Robot-Assisted Sialolithotomy and Sialendoscopy (RASS). We compared the characteristics of retrieved stones, surgical success rate, operative time, and post-operative complications in both techniques. True surgical success was defined as successful stone extraction without reoccurrence within 12 months.

RESULTS

The RASS technique was attempted in 60 patients and successful in 56 (93.3%) cases whereas the IMAS technique was performed in 52 patients and successful in 48 (92.3%) cases. The longest dimension of the predominant retrieved calculi was 9.6 ± 3.1 mm (range, 5-18 mm) for the robotic technique and 10 ± 4.8 mm (range, 5-30 mm) for the microscopic technique. The operative time for the robotic technique excluding robot setup time was 70.6 ± 24.8 min compared to 61.9 ± 42.4 min for microscopic technique (p = 0.018). No major adverse outcomes were reported; however, temporary lingual paresthesia was found in ten robotic (16.7%) and five microscopic (9.6%) cases.

CONCLUSION

The two techniques were comparable in terms of efficacy and safety for large stones. The robot has the advantage of intraoral high dynamic maneuverability and improved surgeon posture while the microscopic technique has the advantage of intraoral tactile feedback. The procedure was significantly shorter in duration with the microscope.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2170-2176, 2024.

Identification of biological components for sialolith formation organized in circular multi-layers

According to the previous studies of sialolithiasis reported so far, this study is aimed to identify the biological components of sialolith, which show different ultrastructures and chemical compositions from other stones, cholelith and urolith. Twenty-two specimens obtained from 20 patients were examined histologically, and analyzed with micro-CT, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). All sialoliths (n = 22) observed in this study showed a central nidus, which was filled with organoid matrix admixed with exosome vesicles, loose calcium apatite crystals, and many bacteria. The micro-CT and SEM observation clearly defined a single or multiple central nidus(es) encircled by highly calcified compact zone. The circular compact zone showed a band-like calcification, about 1-3 mm in thickness, and usually located between the central nidus and the peripheral multilayer zone. But some sialoliths (n = 5) showed severe erosion of compact zone by expanding multilayered zone depending on the level of calcification and inflammation in sialolith. By observing TEM images, many exosome vesicles and degraded cytoplasmic organelles were found in the central nidus, and some epithelial cells were also found in the calcified matrix of peripheral multilayer zone. Particularly, EDS analysis indicated the highest Ca/P ratio in the intermediate compact zone (1.77), and followed by the central nidus area (1.39) and the peripheral multilayer zone (0.87). Taken together, these data suggest that the central nidus containing many inflammatory exosomes and degraded cytoplasmic organelles has a potential to induce a band-like calcification of compact zone, and followed by the additional multilayer deposition of exfoliated salivary epithelial cells as well as salivary materials. Thereby, the calcium apatite-based sialolith is gradually growing in its volume size, and eventually obstructs the salivary flow and provides a site for the bacterial infection.

Salivary Gland Diseases: A Retrospective Clinicopathological Study of 159 Cases

Background

Salivary gland diseases include a variety of conditions (inflammatory, immunological, infectious, or neoplastic pathologies). Salivary gland diseases hold the interest of clinicians and pathologists due to their varied clinical presentation and histological diversity. In this study, we aimed to assess the various aspects of clinical and pathological characteristics of salivary gland diseases.

Methodology

We reviewed the records of patients with various salivary gland diseases at Ramadi Teaching Hospital, Rashid Hospital, Razi Hospital, and Zuhur Hospital in Iraq. The study covered the years 2010 to 2021.

Results

Of 159 patients, there were 61.64% female patients. The age group most affected was 51-60 years (26.4%). The most involved salivary gland was the parotid (44.65%). Swelling was seen in 74% of the patients. Obstructive lesions were seen in 52.2% of patients. Obstructive pathologies occurred exclusively in the age group 51-60 years, infective cases involved the age group 71-80 years (64.3%), and tumors affected the age group 41-50 years (77.4%). Women were affected more than men by all pathologies. The parotid gland was mostly affected by tumors (32/71), while other glands were mostly affected by obstructive lesions (17/18). A significant association was found between salivary gland pathologies with age and the affected gland. The most common clinical entity of the obstructive lesions was xerostomia (20.1%). While pleomorphic adenoma was the most common tumor (n = 40/50). The most common cause of xerostomia was smoking (31.2%) and the least cause was antidepressants (9.4%).

Conclusions

Salivary gland diseases were mostly seen in women and in the age group 51-60 years. Parotid was the most involved gland. A three-quarter of the cases presented with swelling and obstructive pathologies comprise above 50% of causes. The age and the involved gland can determine the type of salivary gland diseases. Xerostomia was the common clinical entity of obstructive pathologies. The most common tumor was pleomorphic adenoma and the most common cause for xerostomia was smoking.

Does saliva composition affect the formation of sialolithiasis?

OBJECTIVE

Saliva composition may affect sialolithiasis formation; thus, this study compared the salivary inorganic composition of sialolithiasis patients with that of healthy controls, and determined whether salivary inorganic composition changes after sialolithiasis surgery.

METHODS

The study included 40 patients with sialolithiasis and 40 matched healthy controls. Patients were examined before and after sialolithiasis surgery; controls were examined once. Flow rate and the inorganic saliva composition in unstimulated whole saliva were assessed.

RESULTS

Patients' salivary flow prior to surgery was significantly lower compared to that of healthy controls, but equalised after surgery. Prior to surgery, patients' saliva exhibited higher concentrations of calcium, magnesium, phosphorous compared to that of healthy controls. The concentration of most ions remained high after sialolithiasis surgery.

CONCLUSION

Sialolithiasis patients had increased salivary concentrations of the ions that constitute the main inorganic phase of most sialoliths, and this may confer a risk for developing sialolithiasis.

Association of serum electrolytes and smoking with salivary gland stone formation

To further define potential factors that may contribute to stone formation in salivary glands (sialolithiasis), a retrospective chart review was performed of patients diagnosed with sialolithiasis between March 1, 1998 and February 29, 2012. Information on salivary gland stone number, location and size, medical history, medications, and serum electrolyte levels were collected. Associations between electrolyte levels and stone characteristics (such as stone number and size) were examined. Fifty-nine patients were identified; their median age was 58 years (range 25-89 years) and most were male (95%). Salivary stones were most commonly located in the submandibular glands (83%). Thirty-five patients (59%) had a smoking history, with 16 (27%) reported as current smokers. There was a significant association between current smoker status and stone size (mean largest stone size 12.4±8.8mm vs. 7.5±4.8mm in current smokers vs. non-smokers; P=0.03). Serum sodium levels (r=0.32, P=0.014) and serum potassium levels (r=0.31, P=0.017) showed significant positive correlations with stone size. While the aetiology of sialolithiasis remains unclear, smoking (which can contribute to reduced saliva flow) and higher serum sodium levels (which can reflect volume depletion) are associated with larger salivary stones.

Vascular Calcification and Stone Disease: A New Look towards the Mechanism

Calcium phosphate (CaP) crystals are formed in pathological calcification as well as during stone formation. Although there are several theories as to how these crystals can develop through the combined interactions of biochemical and biophysical factors, the exact mechanism of such mineralization is largely unknown. Based on the published scientific literature, we found that common factors can link the initial stages of stone formation and calcification in anatomically distal tissues and organs. For example, changes to the spatiotemporal conditions of the fluid flow in tubular structures may provide initial condition(s) for CaP crystal generation needed for stone formation. Additionally, recent evidence has provided a meaningful association between the active participation of proteins and transcription factors found in the bone forming (ossification) mechanism that are also involved in the early stages of kidney stone formation and arterial calcification. Our review will focus on three topics of discussion (physiological influences-calcium and phosphate concentration-and similarities to ossification, or bone formation) that may elucidate some commonality in the mechanisms of stone formation and calcification, and pave the way towards opening new avenues for further research.

Proteomic and scanning electron microscopic analysis of submandibular sialoliths

OBJECTIVES

Several theories have been proposed regarding the genesis of sialoliths, including the organic core theory, which suggests epithelial or bacterial etiology originating in the central core. Our aim was to use novel methodologies to analyze central areas (the core) of calculi from sialolithiasis patients.

MATERIALS AND METHODS

The structures of the halves of six submandibular salivary stones were analyzed by scanning electron microscopy (SEM). After structural analysis, from the other six halves, samples from the central parts of the core and peripheral parts of the core were digested with trypsin and analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The peptide mass fingerprints were compared with the results of in silico digestion.

RESULTS

SEM analysis of the sialoliths showed that organic structures (collagen/fibrous-like structures, bacterial fragments) were visible only outside of the core in the concentric layers of external areas, but not in the core area. The mass spectrometry (MS)/MS post-source decay experiments were completed from the four, most intense signals observed in the MS spectrum and human defensin was proven to be present in three of the examined samples, originated from the peripheral region of three cores.

CONCLUSIONS

Although proteomic analysis demonstrated defensin protein in the peripheral region of the core in three sialoliths, SEM failed to prove organic structures in the core.

CLINICAL RELEVANCE

New investigation modalities still cannot prove organic structures in the core, henceforward challenging the organic core theory.

Sialolithiasis of the submandibular gland

Sialolithiasis of the salivary gland is a benign pathology that occurs most frequently in the submandibular gland because of its anatomic features. Depending on the sialolith size and calcification degree, it can be visible in radiographic examinations. Commonly, patients may experience pain and/or edema, when the ducts are obstructed. The authors report the case of sialolithiasis of the submandibular gland in a 42-year-old, female, white-skinned patient, noticed during routine dental examination. Following diagnosis confirmed by clinical and radiographic examinations, the treatment plan consisted of surgery for removal of the calcified mass. The prognosis is often good, and generally there is no recurrence.

Effects of glucocorticoid on adipocyte size in human bone marrow

The pathogenesis of corticosteroid-induced femoral head necrosis is assumed to be related to lipid metabolism. Mature fat cells are believed to play a central role in lipid metabolism. The purpose of this study was to investigate the size of mature fat cells in the human femoral head after steroid treatment. Cancerous bone tissue was obtained from the femoral heads of 20 women who had undergone total hip arthroplasty. This bone tissue was subsequently incubated in a medium containing 10(-7) or 10(-5) M dexamethasone for 5 days. Mature fat cells from the bone marrow were observed by scanning electron microscopy, and the largest diameter of individual fat cells was measured. The size of the mature fat cells in human bone marrow increased after high-dose steroid treatment. The largest fat cell volume after steroid treatment was one and one-half times larger than that observed in the control. Steroid-induced osteonecrosis is known to sometimes occur after high-dose steroid treatment. These findings may indicate the pathogenetic factors in the early stage of steroid-induced osteonecrosis.

Sialolith characterization by scanning electron microscopy and X-ray photoelectron spectroscopy

The objective of this study has been to characterize sialolith, a calcium phosphate deposit that develops in the human oral cavity, by high-resolution field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The morphological and chemical data obtained helped in the determination of their formation mechanism in salivary glands. Sialoliths in the submandibular salivary glands may arise secondary to sialodenitis, but not via a luminal organic nidus. We believe this is the first study that characterizes a sialolith by XPS.

Long-term evaluation of extracorporeal shock wave lithotripsy in the treatment of salivary stones

Extracorporeal shock wave lithotripsy is a rather new therapeutical method in the treatment of sialolithiasis. The objective was to evaluate retrospectively the results of the extracorporeal shock wave lithotripsy therapy performed with a Minilith SL 1 lithotripter on 167 out-patients with symptomatic stones (average size 5.94 mm) of the salivary glands over an observation period of seven years. A successful treatment with total stone disintegration was achieved in 51 (31 per cent) patients. In 92 (55 per cent) patients treatment was partially successful, with disappearance of the symptoms but a sonographically still identifiable stone. Treatment failure occurred in 24 (14 per cent) patients who then underwent surgery. The mean follow-up period was 35.6 months (minimum three, maximum 83), after which 83.2 per cent of the initially successfully treated patients were still free of symptoms.Therefore, extracorporeal shock wave lithotripsy, as a non-invasive treatment alternative with few side effects, is an efficient technique for the therapy of sialolithiasis in selected patients.