Salivary stone disease

Sialolithiasis (synonyms: calculous sialadenitis, sialolithiasis) has been known for a long time. Thus, Hippocrates associated the disease with gout. The term "sialolithiasis" was introduced by L.P. Lazarevich (1930), since he considered the process of stone formation in the salivary glands to be a disease.

Previously, salivary stone disease (SLD) was considered a rare disease. In recent years, it has been established that SLD is the most common disease among all salivary gland pathologies; according to different authors, it accounts for 30 to 78%.

Most often, the stone is localized in the submandibular (90-95%), less often - the parotid (5-8%) salivary glands. Very rarely, stone formation was observed in the sublingual or minor salivary glands.

There is no gender difference in the incidence of salivary stone disease, but the disease is observed 3 times more often in city dwellers than in rural areas. Children rarely get sick.

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Causes of salivary stone disease

Salivary stone disease is a polyetiological disease. Currently, individual links of its pathogenesis are known. As is known, in the norm, microsialoliths are constantly formed in the salivary glands, which are freely washed out into the oral cavity with the flow of saliva.

The formation of stones is based on the presence of congenital changes in the salivary glands (Afanasyev V.V., 1993) such as local dilation (ectasia) of ducts of various calibers and a special topography of the main duct in the form of a broken line with sharp bends in which a calculus is formed. In these dilated areas of the ducts, when the secretory activity of the gland is impaired by hyposialia, saliva with microstones accumulates and is retained. Additional factors that contribute to the formation of salivary stones and lead to the growth of the calculus are considered to be: the presence of a violation of mineral, mainly phosphorus-calcium, metabolism; hypo- or avitaminosis A; the introduction of bacteria, actinomycetes or foreign bodies into the duct of the salivary gland; long-standing chronic sialadenitis.

The rare formation of stones in the parotid gland is associated with the fact that its secretion contains statherin, which is an inhibitor of the precipitation of calcium phosphate from saliva.

Salivary stones, like all organomineral aggregates in the human body, consist of mineral and organic substances: organic matter predominates, making up to 75-90% of the total mass. In the amino acid composition of the organic component of salivary stones, alanine, glutamic acid, glycine, serine and threonine predominate noticeably. This composition of the organic component is generally similar to that in dental stones. In the center of the stone there is often a core represented by organic matter, salivary thrombi, exfoliated epithelium of the ducts, actinomycetes, and a cluster of leukocytes. Sometimes foreign bodies also serve as such a core. The core of the stone is surrounded by a layered (lamellar) substance in which spherical bodies are located. The occurrence of layering in salivary stones can be associated with daily, monthly, seasonal and other rhythms in the human body.

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Symptoms of salivary stone disease

Symptoms of salivary stone disease depend on the stage of the disease, the form and location of the salivary stones, the state of the body and other factors.

The main and characteristic symptoms of salivary stone disease are pain and swelling in the area of the affected salivary gland during meals or when seeing spicy and salty food, this symptom is called "salivary colic". Pain is the leading symptom in the clinical picture of the disease. A case of attempted suicide due to pain experienced by the patient is described in the literature.

Depending on the location, shape and degree of mobility of the stone, the pain may have a variety of characters. If the stone is immobile and does not interfere with the outflow of saliva due to the presence of one or more grooves on its surface, then there may be no pain. Such a stone is usually called silent.

In the initial stage of salivary stone disease, the disease develops asymptomatically over a long period of time. The stone is discovered accidentally during an X-ray examination of a patient for some odontogenic disease. The first symptoms of the disease appear when the outflow of saliva is disrupted during meals, especially sour and spicy ones ("salivary colic"). Patients note the periodic appearance of a dense painful swelling in the area of the affected salivary gland. The appearance of pain during meals is associated with the stretching of the gland ducts due to their obstruction by a stone, preventing the outflow of saliva into the oral cavity. After eating, the pain and swelling gradually subside, and a salty-tasting secretion is released into the oral cavity. Sometimes the pain is paroxysmal and does not depend on food intake. "Salivary colic" can be of varying intensity.

Retention of secretion is observed when the stone is localized in the submandibular and parotid ducts or in the intraglandular parts of the ducts. The secretion retention lasts from several minutes to several hours and even days. Then it gradually passes, but recurs during the next meal. The enlarged gland is painless and soft upon palpation; when the stone is located in the gland, there is a compacted area. During bimanual palpation along the submandibular duct, a small, limited compaction (stone) can be detected. The mucous membrane in the oral cavity and in the area of the duct mouth may be without inflammatory changes.

When probing the duct, if the stone is located in the anterior and middle sections of the submandibular duct, a rough surface of the calculus is determined.

If at the initial stage of the disease patients do not consult a doctor for a long time, inflammatory phenomena increase and the disease progresses to a clinically expressed stage.

During this period of the disease, in addition to the symptoms of saliva retention, signs of exacerbation of chronic sialadenitis occur.

An exacerbation of the process in the presence of a stone in the duct or gland in some patients may be the first manifestation of the disease, since the stone is not always an obstacle to the outflow of saliva.

In this case, the symptom of “salivary colic” may not be present.

Patients complain of painful swelling in the sublingual or buccal areas, depending on the affected gland, difficulty eating, increased body temperature to 38-39 °C, general malaise. During external examination of the patient, swelling is detected in the area of the corresponding gland. Palpation reveals sharp pain in the gland area. Sometimes signs of periadenitis are observed, with diffuse swelling appearing around the gland. Examination of the oral cavity reveals hyperemia of the mucous membrane of the sublingual or buccal areas on the corresponding side. Palpation reveals a dense painful infiltrate along the duct. Bimanual palpation can be used to feel the submandibular duct as a cord. As a result of significant infiltration of the duct walls, it is not always possible to establish the presence of a stone in it by palpation. In this case, a more compacted painful area is detected along the duct at the location of the calculus. When pressing on the gland or palpating the duct, especially after probing it, a mucopurulent secretion or thick pus is released from the mouth (often in significant quantities).

Symptoms of late stage salivary stone disease

Sometimes the anamnesis indicates repeated exacerbations. With each exacerbation of the process, the changes in the gland increase, and the disease moves to a late stage, in which clinical signs of chronic inflammation are expressed. Patients complain of constant swelling in the area of the salivary gland, mucopurulent discharge from the duct, signs of "salivary colic" are rarely noted. In some patients, gland compaction occurs gradually, without repeated exacerbations and saliva retention. During examination, swelling can be established, limited by the gland, dense, painless on palpation. Mucus-like secretion with purulent inclusions is released from the excretory duct when massaging the gland; the duct opening is dilated. Palpation along the parotid or submandibular duct reveals its compaction due to pronounced sialodochititis. Sometimes it is possible to identify a stone by the presence of a significant compaction in the duct or gland and the simultaneous occurrence of stabbing pain. During examination, a decrease in the secretory function of the affected gland is determined. The cytological picture is characterized by clusters of partially degenerated neutrophils, a moderate number of reticuloendothelial cells, macrophages, monocytes, sometimes - columnar epithelial cells in a state of inflammatory metaplasia; the presence of squamous epithelial cells. Sometimes goblet cells are determined. With a significant decrease in the function of the salivary gland, ciliated cells can be found in the mucous contents. When the stone is located in the gland, in addition to the cells indicated, cubic epithelial cells are found.

Classification of salivary stone disease

In clinical practice, the most convenient classification is that proposed by I.F. Romacheva (1973). The author identified three stages of disease development:

1. initial, without clinical signs of inflammation;
2. clinically expressed, with periodic exacerbation of sialadenitis;
3. late, with pronounced symptoms of chronic inflammation

The stage is determined by the clinical picture and the results of additional research methods. Particular attention is paid to the functional state of the salivary gland and the severity of pathomorphological changes in it.

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Diagnosis of salivary stone disease

In recognizing salivary stone disease, it is important not only to establish the presence, localization, size and configuration of stones, but also to identify the cause of stone formation, as well as the conditions predisposing to it and relapses. At the same time, it is necessary to determine the functional state of the salivary gland.

General, specific and special methods are used to diagnose salivary stone disease.

An important anamnestic sign of salivary stone disease is an enlargement of the salivary gland during meals. Bimanual palpation can sometimes detect a stone in the thickness of the submandibular gland or along its duct. Small stones can be felt only near the mouth of the duct. The submandibular duct should be palpated by moving the fingers from back to front so as not to displace the suspected calculus into the intraglandular part of the duct. If the stone is located in the anterior part of the parotid duct, it is palpated from the side of the mucous membrane of the cheek; with premasseteric and masseteric localization, it can be detected from the side of the skin.

During bimanual palpation, a lump in the gland can be determined not only in the presence of a stone, but also in the case of chronic infection, phleboliths, inflammation of the lymph nodes, amyloidosis, and polymorphic adenoma.

Probing the duct allows to detect the stone and determine the distance to it from the mouth. Contraindication to probing (due to possible perforation of the duct wall) is the presence of exacerbation of sialadenitis. For probing, salivary probes of different diameters are used. They have a flexible working part and different diameters, which significantly facilitates probing and allows to determine the diameter of the mouth of the excretory duct.

The leading role in recognizing salivary stone disease belongs to radiation methods of examination (radiography, sialography, etc.). Usually, the examination begins with a survey X-ray of the gland. Survey X-ray of the parotid gland is performed in a direct projection. In the lateral projection, it is difficult to detect a salivary stone due to the superposition of the shadows of the skull bones. For X-ray of the anterior part of the parotid duct, the X-ray film is placed in the vestibule of the mouth in the area of the mouth, and the X-rays are directed perpendicular to the surface of the cheek.

For radiography of the submandibular gland, a lateral projection or the method proposed by V.G. Ginzburg in the 1930s is used, in which the film is applied to the skin in the submandibular region on the affected side, and the X-rays, with the mouth maximally open, are directed from top to bottom and towards the affected gland between the upper and lower jaws. To detect a stone in the anterior section of the submandibular duct, radiography of the floor of the mouth, proposed by A.A. Kyandsky, is used.

To detect a salivary stone located in the posterior part of the submandibular duct, an X-ray setup is used to examine the tissues of the floor of the oral cavity. For this, the patient's soft palate mucosa is treated with a 10% lidocaine solution before the examination, the X-ray film is placed in the mouth between the teeth until it touches the soft palate, the patient tilts his head back as far as possible, and the X-ray tube is placed on the patient's chest on the affected side. Using this technique, it is possible to detect a stone located in the intraglandular part of the submandibular duct.

It is not always possible to detect the shadows of concretions on general X-ray images. Often the shadow of the stone is superimposed on the bones of the facial skeleton. In addition, stones can be radiopaque or low-contrast, which depends on their chemical composition. According to I. F. Romacheva (1973), V. A. Balode (1974), radiopaque salivary stones occur in 11% of cases.

To improve diagnostics and stone detection, V.G. Ginzbur proposed sialography. For sialography, it is better to use water-soluble radiopaque substances (omnipaque, trazograf, urografin, etc.), since they are less traumatic to the gland. Sialography makes it possible to detect radiopaque salivary stones, which look like duct filling defects on sialograms.

Sialograms reveal uniform expansion of the ducts posterior to the location of the stone. The contours of the ducts are smooth and clear in the initial period of the disease; the greater the number of exacerbations suffered by the patient, the more significantly the ducts are deformed. Ducts of the gland of the first to third orders are dilated, deformed and discontinuous. Sometimes the contrast agent fills the ducts unevenly. The parenchyma of the gland is not clearly defined or is not defined, which depends on the stage of the process. In the case of a non-radiographic stone, it is detected as a filling defect.

Echosialography is based on the different absorption and reflection of ultrasound waves by different tissues. The stone reflects ultrasound waves, creating a picture of an acoustic shadow or sound track, the width of which can be used to judge its size.

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Pathomorphological examination

In the cytological examination of the secretion, in the case of the stone being located in the gland, neutrophilic leukocytes predominate on the cytograms, partly in a state of necrobiological destruction, a large number of erythrocytes, which indicates trauma to the ductal epithelium by the stone. Columnar epithelium is found in clusters and individual specimens, squamous epithelial cells - in moderate quantities. When the stone is located in the duct, the cellular composition of the secretion is much poorer, there is no columnar epithelium, more squamous epithelial cells are noted. With an exacerbation of the process, regardless of the localization of stones, the number of cellular elements increases. The data of the cytological examination of the gland secretion must be compared with the data of other research methods.

Conventional and multispiral computed tomography is used to detect and establish the spatial location of salivary stones, which is necessary when choosing a treatment method. Computed sialotomography also allows for the detection of non-radiographic stones. Modern computed tomography scanners allow for the creation of a three-dimensional model of tissues of a given density.

Differential diagnostics of salivary stone disease should be carried out with non-calculous acute and chronic sialadenitis, neoplasms of the salivary glands, cysts, lymphadenitis, osteoma of the lower jaw, phleboliths, petrification of the lymph nodes in tuberculosis, etc. A characteristic anamnesis and objective examination data allow in most cases to make the correct diagnosis.

Treatment of salivary stone disease

Treatment of salivary stone disease involves not only removing the stone, but also creating conditions that prevent recurrence of stone formation.

The location of a salivary stone in the intraglandular ducts is often the reason why doctors remove the salivary gland along with the stones.

The operation of removing the salivary gland, especially the parotid gland, is quite a complex task; it is associated with the risk of complications such as injury to the branches of the facial, lingual and hypoglossal nerves, leaving a stone in the duct stump or in the surrounding tissues. A poorly ligated duct stump may later serve as a source of infection.

It is known that the salivary glands play an important role in the human body as an organ of exocrine and endocrine secretion. After the removal of one of the major salivary glands, its function is not restored at the expense of the others. Studies have shown that after the removal of the salivary glands, especially the submandibular gland, various diseases of the gastrointestinal tract develop, such as gastritis, colitis, gastroduodenitis, cholecystitis, etc. Therefore, extirpation of the salivary gland in patients with salivary stone disease is undesirable.

Conservative treatment of patients with salivary stone disease is ineffective and is used mainly when the stone is small and located near the mouth of the duct. For this purpose, patients are prescribed substances that stimulate salivation. In this case, small stones can be thrown out by the flow of saliva into the oral cavity. It is advisable to combine the use of salivary drugs with preliminary bougienage of the duct.

Some authors recommend the following method, called "provocative test". If the calculus is small (0.5-1.0 mm), the patient is given 8 drops of 1% pilocarpine hydrochloride solution orally. At the same time, the mouth of the excretory duct is probed with a salivary umbrella of the largest possible diameter and left in the duct as an obturator for 30-40 minutes. Then the probe is removed. At this time, a large amount of secretion is released from the widened mouth of the duct, and a small stone may be released along with it. However, this method rarely allows success.

I. I. Chechina (2010) developed a method of conservative treatment of salivary stone disease. The author proposed introducing 0.5-1.0 ml of 3% citric acid solution into the excretory duct of the salivary gland daily for 10 days. At the same time, the patient is prescribed the following medicinal complex orally: Canephron N, 50 drops 3 times a day; 3% potassium iodide solution, a tablespoon 3 times a day; knotweed herb infusion, 1/4 cup 3 times a day. The course of treatment is 4 weeks. In the last week of treatment, oral administration of 3% potassium iodide solution is replaced by ultraphonophoresis. The courses are repeated after 3 and 6 months. According to I. I. Chechina, small stones can pass on their own or decrease in size, which prevents the development of "salivary colic." This method can be an alternative, but in most cases cannot replace surgical removal of the calculus.

Surgeries for salivary stone disease

If the stone is located in the parotid or submandibular ducts, as well as in the intraglandular ducts of the parotid gland, then surgical removal of the stones is indicated. If the stone is located in the intraglandular ducts of the submandibular gland, then the gland is removed together with the stone.

Removal of stones from the submandibular and parotid ducts is performed in outpatient settings. Removal of stones from the intraglandular parts of the parotid gland and extirpation of the submandibular salivary gland are performed in hospital settings.

If the stone is located in the anterior part of the parotid duct, it can be removed by intraoral access using a linear incision of the buccal mucosa - along the line of closure of the teeth or a semi-oval incision and cutting out a flap bordering the mouth of the duct, using the Afanasyev-Starodubtsev method if the stone is located in the middle or posterior parts of the parotid duct.

If the stone is located in the distal parts of the parotid duct, it can be removed through the oral approach using a curettage spoon inserted to the anterior edge of the parotid salivary gland after dissection of the duct.

If the calculus is located in the parotid gland, it is removed extraorally by folding back the skin-fat flap using the Kovgunovich-Klementov method.

If the salivary stone is located in the anterior and middle sections of the submandibular duct, it is removed by intraoral access using a linear or tongue-shaped incision made in the sublingual region. After removing the stone, it is advisable to form a new duct opening using our method (Afanasyev V.V., Starodubtsev V.S.) for better secretion drainage in the future.

In case of salivary stone disease and significant dilation of the intraglandular part of the parotid duct (up to 1 cm in diameter), we use the following technique: an external incision is made, according to Kovtunovich-Khlementov, and the skin-fat flap is peeled off, exposing the parotid gland. The parotid duct is dissected along its dilated part. The duct is dissected along its entire length and at the ends it is dissected with transverse incisions. After opening the duct, medicinal sanitation of the ducts and removal of stones are performed. The resulting duct flaps are screwed inward and sutured to its inner part. At the outlet of the duct, it is ligated to extinguish the function of the gland.

It is necessary to remove the salivary gland only in cases of frequent recurrence of the disease and the impossibility of surgical removal of the stone.

Complications after surgery for salivary stone disease

During and after surgical treatment of patients, a number of complications may develop.

External salivary fistulas usually develop after removal of a stone from the parotid gland by external access. Fistulas present certain difficulties for the surgeon. A number of operations are proposed for their closure.

Branches of the facial nerve can be damaged during interventions on the parotid salivary gland. Conduction disturbances in them can be persistent when the nerve is cut and temporary when it is compressed by edematous tissues.

When removing the submandibular salivary gland, the marginal branch of the facial nerve may be damaged, which leads to a loss of tone of the triangularis muscle of the lower lip.

Damage to the lingual or hypoglossal nerves may occur when the submandibular salivary gland is removed or when removing a salivary calculus through the lingual groove. This may result in permanent loss of sensation in half of the tongue.

Cicatricial stenosis of the ducts often occurs after the removal of a stone. They often form in cases where the removal is performed during an exacerbation of salivary stone disease. To prevent cicatricial stenosis of the duct after the removal of a stone, it is recommended to create a new opening. When a cicatricial stenosis forms in the duct, it is necessary to perform plastic surgery to create a new opening of the duct behind the site of stenosis using the Afanasyev-Starodubtsev method. If this cannot be done, an operation to remove the salivary gland is indicated.

Surgical treatment of patients with salivary stone disease is traumatic, complications are possible after stone removal. Frequent relapses force to resort to repeated interventions in more difficult conditions. These problems, as well as the lack of effective conservative methods of treating patients, led to the development of extracorporeal shock wave lithotripsy, or remote lithotripsy (RSL), which in recent years has become an alternative to traditional methods of treating patients with salivary stone disease.

To crush salivary stones, lithotripters Minilith, Modulith Piezolith and others are used.

The essence of DLT is that the stone is crushed using shock waves. Treatment using the DLT method can be carried out if the stone is located in the intraglandular section of the submandibular duct and in all sections of the parotid duct. A prerequisite for DLT is good drainage of secretion from the gland (absence of duct stricture in front of the stone) or the possibility of creating drainage surgically. There are no restrictions on the use of DLT depending on the size of the stone. The method of shock wave sialolithotripsy in the Russian Federation was developed in detail by M.R. Abdusalamov (2000), later Yu.I. Okonskaya (2002) confirmed the author's conclusions about the effectiveness of the stone crushing technique. Not all stones are crushed. Thus, V.V. Afanasyev et al. (2003) found that soft stones containing mainly organic elements are difficult to crush. Hard stones can be crushed in different modes.

Recurrence of stone formation may occur both after spontaneous passage of the salivary stone and after surgical removal or with the help of ESWL. The cause of recurrence may be the body's tendency to stone formation and the leaving of stone fragments in the duct after surgical intervention or crushing. In these cases, removal of the salivary gland is recommended.

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