What is the submandibular gland?
The submandibular glands are a pair of salivary glands under the jaw (mandible). They produce saliva which drains via a long duct, opening under the tongue at the front of the mouth. The saliva secreted by the submandibular gland is a thicker and contains more calcium than that produced by other salivary glands. Because of this, the submandibular gland is prone to making stones in its duct.
What problems can you have with the submandibular gland?
The commonest problem is blockage of the salivary duct. This can be caused by stones or narrowing of the salivary duct. Blockage leads to painful swelling of the gland which is worse when you eat. The swelling may resolve spontaneously. However if it does not, then infection can occur, with marked swelling, redness and pain at the angle of the jaw. Treatment includes antibiotics, as well as removal of the stone (via the mouth) or removal (excision) of the gland.
Lumps or growths can also occur in the submandibular gland. These lumps are often benign but if you do have a growth here, it needs to be removed, as up to one half of them can be cancer.
What investigation are you likely to have?
An ultrasound is the most common test you will have. It can show if there any any stones in the gland. A needle test (to remove cells that form a lump in the saliva gland) may be performed also. These cells are examined under a microscope, to provide more information as to the nature of the lump.
An X-ray of the floor of the mouth can be helpful to show a stone in the saliva duct.
Sometimes a sialogram is performed. This is where the submandibular duct is filled with contrast dye, to outline the drainage system of the gland. It will show any blockages in the duct, and can outline stones also.
Occasionally a CT scan is performed.
Why operate on the submandibular gland?
If stones inside the duct do not come out, the gland may swell up when you eat. These stones can be removed. This procedure is done through the mouth either under a local or general anaesthetic. It is performed as day case surgery.
If stones are stuck deep in the duct or within the gland itself then the gland can become permanently inflamed and swollen. This may cause recurrent pain and infection. If these symptoms are ongoing, then it is better to have the gland removed.
If a lump develops in the submandibular gland then the gland should be removed. As a fairly high number of submandibular lumps can be cancerous the whole gland should be removed. By removing the gland we can find out whether it is benign or cancerous.
The operation to remove the gland:
The operation is performed under general anaesthetic, with you asleep. The cut is made in the neck, along a skin crease line, below the jaw where the submandibular gland lies. The operation will take about an hour and a half. At the end of the operation a drain (plastic tube) is placed through the skin to prevent any blood clot collecting under the skin. This is removed the day after surgery. Most people can go home the day after surgery. You will need 2 weeks off work.
If blood collects under the skin then a haematoma forms. The drain is placed in the wound to try and prevent this. This occurs in up to 5% of patients and it is sometimes necessary to return to the operating theatre and remove the clot and replace the drain.
Wound infection is uncommon in the neck but can occur, particularly if the gland has had many infections before the operation. Wound infection will require antibiotic treatment. If and abscess were to form, this would need to be drained in the operating theatre.
Facial weakness: There is an important nerve that passes under the chin close to the submandibular gland. It makes the lower lip move. If it is damaged during the surgery it can lead to a weakness of the lower lip. In most cases this nerve works normally after the surgery, however in some cases weakness of the lower lip can occur, particularly when the gland is badly inflamed or if the nerve is stuck to a lump. This weakness is usually temporary and can last for 6-12 weeks. Occasionally there is a permanent weakness of the lower lip following this surgery.
The skin around the wound may be numb after the operation. If that happens the numbness will usually improve over the next three months. The nerve which gives sensation and taste to one half of the tongue runs close to the duct of the gland. It very rarely gets injured. However, if this nerve is damaged your tongue may feel numb immediately after the operation. This will usually improve with time and permanent numbness of the tongue is rare. Another nerve runs close to the submandibular gland that supplies the muscles of the tongue on that side (and hence helps with movement of the tongue). It would be very unusual for this nerve to be damaged in this surgery.
Will my mouth be dry?
No, you will not notice a dryness of the mouth. The mouth has many salivary glands throughout it that provide ample saliva to the mouth.