Complications of Parathyroid Surgery
Parathyroid surgery is very safe, but like all surgery carries certain risks. The aim is to make the operation as safe as possible, but very occasionally things can go wrong and a complication can occur. These fall into three main areas:
1. Complications of the anaesthetic
Your anaesthetist will discuss with you any possible complications related to the anaesthetic.
2. General complications of any operation
Bleeding
Fig.1: Small postoperative haematomaThe parathyroid glands lie close to a number of large and small vessels, so there is a small risk that bleeding can occur in the neck after any form of parathyroid surgery, requiring a second operation to stop the bleeding and clear out any clot in the neck. Multiple precautions are taken to minimise the risk of this complication (see Parathyroid Surgery).
In most cases any bleeding is slow and minor, which may produce a clot (haematoma) under the wound (Fig. 1). This occurs in less than 1% of cases. It may be associated with obvious bruising to the skin, but usually requires no treatment as it will resolve by itself with time.
Occasionally, if the haematoma is large, it will need a minor procedure in outpatients to drain the clot, but no anaesthetic is needed. Although it can look unsightly initially, it is important to note that the long term cosmetic outcome is not affected by these small haematomas.
If you are taking warfarin or clopidogrel these can increase the risk of bleeding in parathyroid surgery. Please tell me if you are taking either of them so that I can advise you about stopping these medications prior to the operation.
Sudden massive bleeding into the neck is extremely unusual after parathyroid surgery, especially minimally invasive (keyhole) surgery. This will usually occur while the patient is in the theatre recovery room or soon afterwards in the ward. It occurs in the first 24 hours after surgery and so almost never occurs out of hospital. This potential risk of bleeding into the neck is why day case parathyroid surgery is avoided and patients are kept in hospital for observation overnight. Because it is a so much smaller risk after parathyroid surgery however, some of these operations can be done as day cases.
Pain
This is unusual after minimally invasive surgery as the cut is smaller and I use lots of local anaesthetic in the wound to minimise discomfort after surgery. Generally only paracetamol (Panadol) is needed to control any pain.
Infection & wound scarring
Infection in the wound is extremely rare. Some patients produce very thick scars (hypertrophic or keloid scars); this is more common in black skinned and fair redheaded patients. In patients with generalized eczema, a new area of eczema may develop along the scar.
3. Complications specific to parathyroidectomy
Swallowing difficulty
Dysphagia (discomfort with swallowing) is uncommon, particularly after keyhole surgery, but the symptoms are temporary and will settle with time.
Low calcium levels in the blood
Fig.2: Tetany due to low calciumThis is very common in the first few days after parathyroid surgery. You may feel tingling or numbness in the fingers or around the mouth, which is an indication that the calcium is low in the blood. In severe cases there may be spasm in the hands or feet, called tetany (Fig. 2), but this is rare.
If a single gland has been removed and the parathyroid disease is mild and the bones not affected, it settles in a day or so. This occurs because the other glands may have been ‘put to sleep’ by the overactive enlarged parathyroid doing all the work.
The remaining glands will usually start working normally in a few days to weeks, but meanwhile you may need to take some calcium and vitamin D supplements. I will advise you about how much to take. These calcium pills (Caltrate Plus) are readily available over the counter at the chemist, and it is worthwhile buying them before surgery so they are on hand at home just in case they are needed after the surgery.
If the bones have been affected, supplementary calcium and vitamin D is given until the bones heal. In some cases vast amounts of calcium and vitamin D must be given to maintain normal serum calcium as calcium pours back into the bones from the blood (hungry bone syndrome).
On occasions it is necessary for a continuous infusion of calcium to be administered intravenously, but this is almost always after longstanding parathyroid disease in renal dialysis patients. This will be managed by the renal physician and the renal team.
When large amounts of calcium with vitamin D are being ingested the serum calcium must be checked weekly, because once the bones have healed the calcium will soar to dangerous levels if the supplements are not stopped. In patients with parathyroid hyperplasia the need for supplements depends not only on the presence of bone disease, but also on the amount of parathyroid tissue removed.
If all of the parathyroids have needed to be removed then you will need to take supplements for the rest of your life.
Change in the voice
Fig.3: Close relationship of RLN and parathyroidsVoice change is one of the most dreaded complications of parathyroid surgery, but fortunately in expert hands is a rare phenomenon. Patients whose voice is their livelihood should discuss in great detail with their physician the need for thyroidectomy.
The nerves to the voicebox run very close to the parathyroids on the back of the thyroid on each side of the neck (Fig. 3) and can be damaged or stretched during the operation, especially if the parathyroid gland is very large or in a difficult position. It can even be adherent to the nerve and need careful dissection to free them from each other.
Damage to the recurrent laryngeal nerve can lead to paralysis of the vocal cord, which can result in a change in the voice. Damage to another nerve (the external branch of the superior laryngeal nerve) can cause difficulty with singing or shouting.
Minor voice changes are not uncommon and are usually transient, lasting for a few weeks. The voice can tire towards the end of the day, and the volume can fluctuate a little in the early days after surgery. Significant hoarseness is usually temporary (2%) but can be permanent in much less than 1% of patients.
Further detail about changes to the voice after parathyroid surgery (which equally applies to thyroid surgery) can be found on the webpage Thyroid Gland and the Voice.
Failure of the operation
This can occur in some patients if the parathyroid is unable to be found (risk is less than 2 in 100 with good localisation). This can occur when there are more than four glands or the overactive gland is in an unusual position, such as in the chest. In this case further investigations will be needed to locate the missing gland.
Patients with hyperplasia who opt for less than total parathyroidectomy must be warned of the risk of recurrence years after initial surgery.