This is a scubcutaneous cavity containing saliva. This condition is usually caused by trauma to salivary gland parenchyma, laceration involving its duct, ducatal stenosis with poor efforts at dilatation. Extravasation of saliva into the surrounding tissues create sialocele.
Sialoceles are common in parotid gland as this gland is commonly involved in facial bone fractures. It is very rare in submandibular and sublingual salivary glands. Injuries to parotid gland present within a day with extensive soft tissue swelling of the face on the side of the injury. This condition is not well recognized and is often misdiagnosed as hematoma. If diagnosis could be made early as soon as the injury has occured an attempt at the primary repair of the duct can be done. If the injury is missed at this stage then an inflammatory pseudo capsule tends to develop. This is infact a protective mechanism which limits further extravasation of saliva into the neck tissue planes. Patient at this stage develops sialocele or external parotid fisutula.
Sialoceles typically appears one to two weeks following injury. In the absence of secondary infection there is no pain. It would appear to be soft and mobile on palpation. Infection happens to be the most important complication and would lead to external salivary fistula.
This is rather common considering the frequency of facial bone fractures. Parotid duct is supposed to course along the middle third of the line drawn from tragus of ear to a point midway between vermillion border of upper lip and the ala of the nose. Any laceration crossing this line should be suspected to have damaged the parotid duct or its accompanying neurovascular bundle and thus should undergo through assessment to diagnose the same.
Attempts at surgical reduction of facial bone fractures also can cause injury to parotid duct causing sialocele.
This is usually straightforward and can be made by clinical assessment and proper history taking. Often there will be history of trauma / surgical wound before the onset of swelling. Aspiration of the cyst will reveal clear fluid and when tested for salivary amylase it would be positive often exceeding 10,000 U/L.
Radiological examination (CT/MRI) have very limited role in detecting injuries to the area of parotid gland.
Ultrasound may help in the assessment of sialocele. Sialography can be performed. Of course it is controversial as it can increase the pressure on sialocele causing rupture and fistula formation.
Minor sialoceles are known to undergo spontaneous resolution by the end of the month because of the formation of scar tissue around the injured salivary parenchyma would seal further flow of saliva into the parenchyma.
1. Repeated aspiration and pressure dressing
2. Administration of antisialogogues like atropine / probanthine can be administered. These drugs should be administered with caution as they have their own set of adverse effects.
3. Formerly local irradiation using 6-20 Gy dose was attempted. It is highly controversial as radiation in this dose is highly carcinogenic.
This falls into two groups.
1. Surgery that reduces parotid secretion
2. Surgery to divert saliva from the lesion into the oral cavity
Surgery to depress parotid secretion:
Salivary duct ligation.
Section of auriculotemporal nerve (Jacobsen's nerve)
Intraoral drainage of sialocele using scalp vein set cannula. This cannula should be left in place for at least a month. Inflammatory response to the cannula and epithelization of the tract surrounding the tube would prevent recurrence.