Why Is Sialendoscopy Preferred for Diagnosing and Treating Salivary Stones?
Salivary duct stones are usually managed surgically, either by the oral surgeon or the otolaryngologist by completely removing the obstruction in the gland for small stones, or by eliminating the entire salivary gland itself in case of complicated and large salivary stones or sialoliths. Alternatively, these can also be eliminated through the marsupialization procedure (surgical procedure often used to treat certain types of cysts or abscesses) of the salivary gland duct and subsequently removing the salivary stone. However, complications of eliminating the stones exist more prominently for Stensen’s duct or parotid gland duct stones, posing a real challenge to both dentists and otolaryngologists.
The advantage of the technique of sialendoscopy over traditional surgical methods is its ability to directly remove smaller parotid gland stones using the sialendoscope itself. In modern-day surgery, larger stones no longer necessitate parotidectomy as they can be broken down using extracorporeal shockwave lithotripsy (ESWL) or laser fiber techniques. These methods involve the passage of surgical instruments or fiber through the sialendoscope for intracorporeal lithotripsy.
What Challenges Does the Parotid Gland Face?
The parotid gland being the major salivary gland in the orofacial cavity inherently poses a greater challenge when it is complicated by the presence of duct stones. Though parotidectomy or complete elimination of the duct would be advised for the treatment of parotid stones, it is now in modern-day dentistry, and surgery is rarely performed. This is mainly because eliminating the parotid or the Stensen's duct can cause an inherent risk of major facial nerve injury (seventh cranial nerve). This again subsequently is an unsolved challenge to dentists, oral surgeons or otolaryngologists because most of these patients would then remain untreated and eventually suffer from recurrent bouts of salivary gland swelling or inflammatory conditions like parotitis. In cases of chronic or recurrent conditions like juvenile recurrent parotitis (JRP), where there is a persistent or recurrent inflammatory condition affecting the patient's parotid glands (commonly may affect the age groups of young children or teens), sialendoscopy can indeed be a boon.
One more alternative technique that has been recently suggested for such complex parotid stones, approved by many surgeons is eliminating the large salivary gland stones through a combined approach called the "sialendoscope guided external approach" which is discussed below in the technique.
What Are the Benefits of Modern Day Sialendoscopy?
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The easiest kind of therapeutic intervention is possible as a drug delivery system via the technique of sialendoscopy for salivary stone removal. This further can increase the local or targeted efficacy of treatment by the oral surgeon (to the salivary glands) as well as reduce the systemic side effects (otherwise one would be encountering the steroid effects than when administered orally).
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Sialendoscopy helps further indirect study, visualization, and precisely evaluating the nature, and length of the ductal strictures (narrowing or constriction in the ducts of the body) or glandular obstructions.
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Sialendoscopy has a further advantage according to current medical research which is that one can monitor the pathological changes that are associated for instance with radioiodine-induced sialadenitis and with its treatment as well.
What Are the Surgical Steps Involved in Sialendoscopy?
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The first step in the sialendoscopy procedure is in the operating room by administering an anesthetic to the patient. While most of the procedures for evaluation or diagnosis via sialendoscopy are performed only under local anesthesia, more complicated cases or large salivary gland obstructions can necessitate general anesthesia as well.
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About 20 to 30 min before the procedure, the oral surgeon places a sterile gauze piece that would be soaked in the 4 % Lignocaine solution (local anesthetic) over the floor of the mouth in either the submandibular gland sialendoscopy (for submandibular gland stones) or within the upper gingivobuccal sulcus (for the parotid or Stensen's duct stones). Therapeutic procedures such as removal of duct calculus or dilatation and stenting of these ductal strictures can be performed preferably under general anesthesia if the surgeon deems fit for the patient.
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Caution should be exercised by the surgeons to avoid giving any antisecretory agents such as Atropine or Glycopyrrolate while performing the procedure. Additional care also needs to be taken to limit the use of the common irrigation solution used during the procedure to avoid Lidocaine toxicity as well as glandular swelling.
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The patient is then after an anesthetic technique with the head fixed onto a headrest and turned preferably towards the surgeon. The patient’s mouth is kept wide open by using the doyen’s mouth gag generally.
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Before starting diagnostic sialendoscopy, sialogogue agents such as lemon or vitamin C tablets can be administered to the patient to facilitate salivary secretions. This allows for easy identification of the ductal strictures and also to maneuver the scope through the salivary gland ductal anatomy. Because the position of the salivary duct punctum would be slightly or quite variable from individual to individual, the surgeon needs to identify and cannulate the gland punctum.
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The punctum is eventually serially dilated using a conical dilator and surgical probes of varied size. Stones less than 3 mm in the salivary ducts such as Stenson’s duct can be managed surgically using the sialendoscope alone.
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Larger stones however need to be broken down into smaller sizes, as elaborated earlier using the ESWL technique or with a microdrill or preferably even a laser.
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In the combined approach, the accuracy or precision of the endoscope is higher and can further decrease individual morbidity by conservatively approaching or localizing the stone in the duct. This is done through conservative skin incisions over the gland and the sialendoscope delivered for localizing the stone. The ducts can be further closed with absorbable sutures after the elimination and are placed extra mucosally with the skin flap reposed in place.
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Individuals operated under local anesthesia can be ideally discharged the same day after only a few hours of monitoring while patients receiving general anesthesia may need extra monitoring and can take longer duration to be discharged till the next day.
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Patients are advised to postoperatively consume only soft food diets that should not be hot or warm. Cold foods and less spicy or bland foods are advised for a few weeks with increased fluid intake. Parotid or submandibular massages would be advised by the surgeon and demonstrated to the individuals.
Are Complications Possible?
Though complications such as perforations involving the duct walls, facial or lingual nerve paresis, and ductal stenosis (a condition characterized by the narrowing of ducts in the body) may exist, they occur only in complicated or challenging cases that do not involve a conservative sialendoscopy procedure or in case of large stones.
Conclusion
Sialendoscopy hence is a conservative dual-purpose diagnostic or therapeutic as well as surgical procedure of choice for salivary stones or obstructions. One of the major advantages of modern-day sialendoscopy is that even steroids which were used only systemically can be easily delivered or targeted by the sialendoscope to eliminate the local pathology in the salivary gland ducts. Sialendoscopy used in these patients of JRP or recurrent cases of parotitis would not only help the oral surgeon or otolaryngologists understand the cause or etiology behind the formation of salivary stones, but it can additionally serve a dual purpose benefit for both surgical and therapeutic elimination of the gland obstruction.
