The parotid gland is a major salivary gland that sits at the top of the neck at the lower end of the ear. It produces saliva which it empties via the parotid duct into the mouth near the second upper molar tooth on the inside of the cheek.
Generally, the parotid gland can be impacted by inflammation or a lump. Inflammation can be caused by blockage by a salivary calculus (stone) or by the body mounting an immune response against the gland. Either way, the gland becomes inflammed (sialadenitis) which causes enlargement and pain, and can eventually destroy the gland.
A lump (tumour) within the parotid gland can be benign or malignant. Benign tumours are the most common. Not all benign tuomours need surgery, although most will continue to grow and they can occaionally transform into a malignancy.
Malignant tumours within the parotid can either arise in the gland or arrive in the gland after starting somewhere else, eg skin or kidney. Malignant tumours that start in the parotid often enlarge locally to involve structure within or near the gland and may spread to lymph nodes. Malignant tumours that spread to the gland often arrive via the lymphatics.
Parotid surgery aims to treat the problem and preserve the facial nerve. The facial nerve is the nerve that moves the face. It travels through the middle of the parotid gland, and injury to the nerve is the most significant complication of parotid surgery.
Sometimes, a cancer in the parotid gland can grow into the nerve and require the sacrifice of the nerve, which results in partial or total paralysis of the face on the effected side.
Most parotid tumours can be safely removed with a very low risk of permanent facial nerve injury. About 15% of patients undergoing parotid surgery for benign conditions have a temporary weakness of face movement, commonyl effecting either the upper or lower lip, or eye closure. In most cases this resolves within months to leave a risk of permanent injury to be about 3%. Often even a permanent injury is only mild.
Other effects of parotid surgery include earlobe numbness, temporary problems with leaking of saliva, sweating of the skin around the area (Frey syndrome) and scar problems.
Branches of facial nerve after removal of tumour from left parotid gland
For larger tumours of the parotid, surgery can cause a defect in the contour of the face.
Some of this effect can be overcome by advancement of tissue in the facelift (SMAS) layer, or by rotating a muscle flap from the sternocleidomastoid muscle. Both of these techniques can be used alone or together to minimize the cosmetic effect of more extensive parotid surgery.
All parotid operations require a general anesthetic and often a 2 night stay in hospital.
Most usually, a drain is left in the wound for 48 hours. This drain is removed prior to going home. Occasionally, a build up of fluid occurs under the wound following release from hospital. This is not a major problem and can be managed by aspiration under ultrasound guidance in the surgery.