The parotid gland, situated around the ear, is one of six major salivary glands. These glands produce the saliva which lubricates the mouth, helps in digestion, protects the teeth, and facilitates taste. Parotidectomy, or removal of the parotid gland, has several indications. These include the removal of benign or cancerous tumours, access for deep lying tumours and rarely, for removal of chronically infected glands.
Parotidectomy is fraught with potentially significant complications. The most worrisome is facial nerve weakness. The facial nerve, which innervates the facial muscles, runs through the parotid gland and therefore, surgery on the gland could interfere with the function of the facial nerve. This may transpire in several ways. If the tumour is cancerous, the nerve may need to be removed along with the tumour itself, in order to achieve a cure. If the tumour is benign, the surgeon will make all attempts to preserve the nerve. However, stretching of the nerve or adjacent cautery may result in temporary or permanent weakness.
The second potential side effect is numbness over the ear and face. This results from stretching or interference with the auricular nerve, which is a sensory nerve overlying the parotid. Usually, the area of numbness will recede with time to about the size of a quarter over the back part of the jaw.
The final risk particular to parotidectomy is Frey's syndrome, which is sweating over the face, on the operated side, whenever the patient eats savoury food. This is troublesome only for a minority of patients.
Currently, there are several techniques available to avoid facial nerve injury. Meticulous surgery is the first and foremost principle. In other situations, particularly in a scarred or previously operated-on gland, a nerve monitor is indispensable for identifying the nerve with the computer before it can be actually seen. If the nerve has to be removed, as in the case of a salivary cancer, an immediate nerve graft can be done.
The numbness over the face can be avoided if the surgeon is able to preserve the auricular nerve and avoid stretching.
Finally, sweating over the face can be treated by applying an antiperspirant to the affected area prior to ingesting the savoury food.
One additional technique worth mentioning is the use of a face-lift incision to avoid an unsightly scar. This technique is particularly applicable for small parotid tumours.
In the end, the potential risks particular to this type of surgery can be avoided or treated with current advancements in technique.