Salivary Glands Anatomy
There are 4 major and numerous minor salivary glands in the body. The major salivary glands are parotid and submandibular glands. The parotid gland is located below the ears and the submandibular gland is located below the jaw on each side and is connected to the oral cavity or mouth through their own ducts that release saliva from the glands to the mouth. The numerous minor salivary glands are located in the mouth.
The major salivary glands are responsible for the production of 90% of saliva in humans with the parotid glands responsible majorly for the salivation during eating and chewing, and submandibular glands responsible for the resting salivation. Various disorders of these glands can result in a variety of symptoms from excess salivation or drooling to reduced salivation and dry mouth. These glands can also be affected by a range of benign and malignant tumors which are characterized by painless swelling of these glands below the ears or jaw. At present, we shall be explaining the contemporary management of salivary ductal obstructive pathologies.
Salivary ductal outflow obstruction
The ducts or tubes connecting the major salivary glands to the mouth can often get obstructed due to calculi (stones) or strictures (narrowing). Such calculi or stones are similar to the stones we encounter in other organs such as gall bladder, urinary tract and kidneys. Symptoms can be sudden of recurrent pain and swelling below the jaw or ears, especially associated with meals, more so citrus predominant.
Initially, this swelling and pain get self-relieved post meals or gentle massage to the glands. As symptoms progress with time, this pain or swelling often becomes chronic and persistent. This can be accompanied by an intra-oral discharge. Stones or strictures may develop inside these ducts due to infections or salivary stasis and cause obstruction to the flow of saliva from these glands, particularly during meals. This leads to sudden swelling of the gland accompanied by pain. Secondary infection of the retained saliva in the glands can also lead to fever and acute glandular infection/sialadenitis, needing antibiotic therapy.
1. What are the common investigations done for confirmation of ductal obstructive pathologies such as stones or strictures?
Ans: Commonest non-invasive investigations are an ultrasound examination of the glands and non-contrast CT scans for evaluating radio-opaque stones. Strictures, however, cannot be evaluated using these methods and need MR sialography sequences.
The gold standard invasive investigation for evaluation of stones or strictures is sialendoscopy or endoscopy of the salivary gland ducts. This is performed in the operating room under general anesthesia.
2. What is sialendoscopy and how is it done? Is it diagnostic or therapeutic?
Ans: Sialendoscopy is a procedure where miniature endoscopes and cameras are used to probe and visualize the salivary ductal system for any pathologies. It is diagnostic and therapeutic. Small stones can be removed through sialendoscopy alone through instrumentation whereas larger stones may need laser fragmentation or combined removal through sialendoscopic visualization and intra-oral incision. The procedure is done in the operating room under general anesthesia but does not require any external facial or neck incision or scar. The procedure can be done in daycare or overnight admission setting.
3. What are the alternatives to sialendoscopy? Are all stones removable endoscopically?
Ans: Alternatives to sialendoscopy are gland excision through an external approach needing longer admission and significant morbidity and potential complications. A decade ago, the only management offered for glands with stones or strictures was the removal of the diseased glands surgically. At present, due to this revolutionary technology, in a significant proportion of patients, the affected glands can be salvaged by just removing the obstructed pathology endoscopically or with minimal access to limited incisions.
No, all stones cannot be removed endoscopically. Very large stones may need to be fragmented by laser and may need removal through intra oral guided incisions. Further, stones located deep inside the gland or proximal to the gland may also not be removed endoscopically, thus needing gland removal surgery.
4. Apart from stones what other pathologies can be managed by sialendoscopy?
Ans: Strictures or localized inflammatory narrowing of salivary ducts also leads to obstructive symptoms such as found in stones, while escaping detection by routine investigations such as ultrasound and CT scans. Strictures can be successfully managed by balloon or bougie dilatation through sialendoscopy. The ducts can also be used endoscopically as conduits for instillation steroids or other drugs directly into salivary glands in case of inflammatory pathologies such as juvenile recurrent parotitis. Ductal stenting is another therapeutic modality possible through sialendoscopic interventions.
Department of Otorhinolaryngology at Manipal Hospital, Dwarka, New Delhi leads the frontier of advanced endoscopic and open interventions of salivary glands including, but not limited to sialendoscopy.