Bones, Calcium, Phosphate, and PTH in Kidney Failure - Parathyroidectomy
The medical name for this operation is parathyroidectomy.
Parathyroidectomy is performed to remove parathyroid glands that are producing too much parathyroid hormone (PTH). Too much PTH causes high calcium levels in the blood and, over a period of time, can cause damage to the bones, blood vessels and heart.
There are usually four parathyroid glands, each one the size of a pinhead (0.1cm). In people with kidney failure needing parathyroidectomy, all of the glands are enlarged, sometimes to the size of a small pea (0.5cm).Parathyroidectomy is also necessary in some people who do not have kidney failure. In these cases only one of the glands is usually enlarged.
It is very rare for enlarged parathyroid glands in a kidney patient to be cancerous.
The operation is technically quite difficult, because the parathyroid glands can be very small and can sit in variable positions. Therefore the operation is performed by a specialist surgeon with particular expertise.
First, several blood tests to measure the PTH level will have been performed, to confirm absolutely that there is a need for the operation.
Because the parathyroid glands can be in variable positions, many surgeons ask for scans of the neck before surgery to try and localise the glands. Scans may use ultrasound (sound waves), X-rays, magnetic scanning, or radio-isotope (nuclear) techniques. Unfortunately none of these scans are perfect, and the results can be disappointing. In many people who clearly have enlarged glands and need surgery, all the scans can be negative. If it is clear from the blood tests that surgery should be performed, negative scans should not prevent the operation going ahead.
Because paralysis of a vocal cord is a possible complication of the operation, an ear, nose and throat (ENT) surgeon may perform an examination of the vocal cords before surgery. This does not involve an anaesthetic, just the surgeon looking at the back of the throat with a mirror or flexible telescope instrument. Some hospitals perform a vocal cord check on everyone, others only if there is a problem with the voice before the operation.
The operation is performed under a general anaesthetic (you are asleep).
Although the operation does not go deep into the body, the surgeon has to operate slowly and carefully. Also, when the surgeon finds the parathyroid glands, it is common to send the samples to the pathology laboratory for an urgent check to make sure a parathyroid gland has been removed (and not a lump of fat or lymph gland, which can look the same). Therefore the operation often takes up to 2 hours.
Recovery from the operation is usually fast, with people being out of bed the next day and walking around the day after. However, because blood tests need daily monitoring for the levels of calcium, most people are in hospital for another 4 or 5 days after the operation.
The surgeon needs to make a cut in the skin about 10cm (4 inches) long. This is made in one of the skin fold in the lower neck, along the line where a necklace might run. The scar normally heals very well, but is clearly in an area where it may be visible. This can affect someones appearance, though usually not badly. The scar can be covered by clothing. It would be under a roll-neck jumper or top, and is also below the level of a shirt with necktie. Some people wear a necklace that is the right size to lie just over the scar.
In most people, however, the scar is either virtually invisible, or does not turn out to be a social embarrassment.
As with any operation, there are possible complications.
- Complications of any operation - Any general anaesthetic carries a risk to the heart, or of chest infection. For someone who is otherwise young and fit, even if they have kidney problems, these risks are not great. However, if someone is older with a history of heart trouble or chest trouble, there may be risks of complications and death. Each person should check with their own doctors about the risks in their case.
- Bleeding in the first couple of hours after surgery - Surgeons are very careful to make sure there is no bleeding at the end of an operation on the neck. However, bleeding can occur. If massive bleeding occurred, a large bruise could develop and compress the windpipe, making it difficult to breathe. For this reason, the cut is normally closed with metal clips, which are easier to remove than stitches if there is bleeding. Fortunately massive bleeding is exceptionally rare (less than 1 in 100 operations), and there is a very careful watch kept on all parathyroidectomy patients for several hours after the operation.
- Vocal cord paralysis, making speech abnormal - The vocal cords are the bands of muscle in the voice box that vibrate and make sounds in other words, they make speech. Unfortunately the nerves which control the vocal cords run right past the positions of the parathyroid glands. If the nerve is cut, the brain cannot tell the vocal cord what to do and speech is affected. If one vocal cord is paralysed, speech is retained but sounds abnormal. If both are lost, speech is very difficult. One of the main jobs for the surgeon doing a parathyroidectomy is to find these nerves (one on each side) and make sure they are not damaged. The rate of vocal cord paralysis is about 1 in 100, unless there has been previous surgery on the neck, in which case the risk is two or three times as high. If there is a vocal cord problem, speech often improves over a few weeks after surgery, as the nerve has been damaged rather than completely cut, and can heal.
- Low calcium levels - When excess PTH is suddenly removed from the blood stream, blood calcium levels can fall. This can be especially severe in people with kidney disease where the bones have been starved of calcium by PTH, as they can soak up large amounts of calcium. Very low calcium levels can cause pins and needles or muscle spasms. It is usually necessary to give large numbers of calcium tablets after parathyroidectomy, and sometimes to give calcium through a drip into a vein.
- Failure of surgery to reduce calcium and PTH levels - Sometimes the operation does not work. This may be because there are 5 parathyroid glands, or one is in an unusual place (even the upper chest), or because a gland in its normal position is missed. These problems can occur with the most careful and expert of surgeons. Further blood tests, scans and surgery are then required.
If all the parathyroid glands are removed, the body has a permanent tendency to low calcium levels, and large numbers of calcium and vitamin D tablets may be necessary for life. Therefore the surgeon often leaves a tiny fragment of parathyroid gland behind, and this may regulate calcium levels normally, reducing the need for tablets. The fragment can be left in its normal position in the neck (the operation is then called sub-total parathyroidectomy). However, because a gland can become overactive some years later and need further surgery, some surgeons prefer to leave the fragment in a position where any future surgery will be easy to perform. Some surgeons put the fragment in one of the neck muscles, and some put it into one of the muscles in the forearm. These operations are called total parathyroidectomy with autotransplantation.
There is no scientific evidence to prove that one of these types of operation is better than the other, so different surgeons continue to perform these slightly different variations of parathyroidectomy. If an individual has questions about the type of operation that would be best in their case, it can be discussed with the surgeon.
Most people with kidney disease who have had parathyroidectomy have to take calcium and vitamin D tablets for some time after the operation. If a portion of gland has been left behind by the surgeon and functions normally, it may be possible to reduce the numbers of tablets.
Long term monitoring of calcium, phosphate and PTH is always necessary, even after successful surgery.
If someone continues to have kidney failure after parathyroidectomy, glands are under constant stimulation and regrowth can occur. Even when the surgeon knows all visible parathyroid tissue has been removed, there is a chance that many years later a gland will appear and more surgery will be needed.
If there is a successful kidney transplant, the stimulus to PTH production goes away or is reduced, and recurrence of PTH problems is rare (so long as there are not problems in the first few months after the transplant).
The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.