Types of Parathyroid Surgery

Successful parathyroid surgery requires a firm diagnosis and good localisation of the tumour preoperatively (see webpage on Primary hyperparathyroidism – Diagnosis), and an experienced surgeon.

Preoperative localisation of the parathyroid is now so accurate that an attempt to locate the parathyroid tumour should be made in all cases prior to surgery. Imaging is now highly specific and sensitive, so that most surgery is now 'image-guided'.

The old adage that ‘the only localisation necessary is to find an experienced parathyroid surgeon’ is out of date, and should instead be ‘the only localisation necessary is to find an experienced parathyroid surgeon who always performs preoperative localisation’.

The aim of the surgeon is to remove the abnormal parathyroid tissue, which has been localised preoperatively, leaving normal parathyroid tissue behind. The perfect result is a normal serum calcium, a normal parathyroid hormone level, an unchanged voice and an almost invisible scar.

The usual approach has been to use general anaesthesia, but the operation can be performed under local anaesthetic when the tumour has been well localised. Parathyroid surgery is a very specialist field, but has a 97-98% cure rate in experienced hands. If a patient needs a second operation the risk of nerve damage rises four-fold unless it is undertaken by a specialist in re-do thyroid and parathyroid surgery.

All of my patients at the Freemasons Hospital will have their surgery performed with an intraoperative nerve monitor, which is used to test and safeguard the recurrent laryngeal nerves (nerves to the voicebox) during your surgery. This nerve monitor minimises the potential risk to the voice to a very low level.

There are many different ways of performing a parathyroidectomy, which all have their indications, advantages and disadvantages. Further detailed information about my parathyroid surgical technique can be found on the webpage Details of Surgery, but this page may contain pictures that some patients may not wish to see.

Detailed information about your surgery can be found on the webpage Guide to Surgery.

1. Focused Minimally Invasive Parathyroidectomy (MIP) 

Since the first unilateral approach in the 1980s, focused MIP has become the method of choice in the 80% of cases where the parathyroid tumour has been localised preoperatively. It is very simple and can be done under local anaesthetic, with a small incision made over the abnormal gland to be removed (Fig. 1).

Fig.1: MIP incision for right sided parathyroid tumourSuccess is checked by frozen section of the tumour, with the pathologist confirming that parathyroid tissue has been removed. Intraoperative PTH measurement is another adjunct to confirm success, but is expensive and not readily available, and in fact adds little to the overall cure rate. If there is any suggestion that there are further tumours then the operation is converted to a traditional 4-gland exploration.

2. Traditional Open Parathyroidectomy

Fig.2: Traditional parathyroidectomy incisionThis is how parathyroid surgery was first done and has stood the test of time for 80 years. It is usually done under general anaesthetic and involves looking at all 4 parathyroids and then removing the abnormal tissue.

It is the procedure of choice if the patient takes lithium or has renal disease, imaging is unable to pre-operatively localise the parathyroid abnormality, localisation suggests multiple gland disease, or in the rare circumstance of parathyroid cancer. It is also the 'fall back position' if a localised parathyroid tumour cannot be found, or a second abnormal gland is found.

This method achieves a 97-98% cure rate, so why not use it all the time? The reason it is limited to only 20% of cases is that preoperative localising scans allow us to cure the majority of cases using a small 2cm incision on only one side of the neck, leaving the rest of the neck (and parathyroid glands) undisturbed, and not the 5 or 6cm central incision of the traditional method (Fig. 2).

Reducing the size of the incision reduces postoperative pain and discomfort and can shorten the hospital stay. It also means any re-exploration is much easier due to reduced scarring in the neck.

3. Minimally Invasive Video-Assisted Parathyroidectomy (MIVAP)

Fig.3: MIVAP techniqueThis uses a small 2.5cm central neck incision and is very similar to the open technique. To aid the surgery a 30-degree endoscope is used, allowing better lighting and magnification, and the surgery is performed while observing on a monitor (Fig. 3).

If the gland is well localised it has little advantage over the MIP technique, although it does allow visualisation of all 4 parathyroid glands through the same small incision.

There is quite a sharp learning curve however, and its complication rate may be higher than MIP. 

4. Endoscopic Parathyroidectomy

Fig.4: Diagram of endoscopic parathyroidectomyThis method is a purely endoscopic technique and for a bilateral exploration needs at least 5 small cuts in the neck (Fig. 4). It has never been popular outside of France.

The equipment is expensive and its use is limited to small parathyroid tumours less than 3 cm in diameter. Because gas has to be infused into the neck there is a risk that gas can be trapped in the tissues which is extremely uncomfortable, although not dangerous.

The view at surgery is excellent however, and it is a very good method if the surgeon has mastered the very steep learning curve, but the conversion rate to open operation is in the region of 13%. One disadvantage which has been reported in the British Journal of Surgery is that if reoperation is necessary, the increased fibrosis in the neck can make the second operation very difficult. 

Some surgeons, particularly in Japan, are attempting to perform this operation through small incisions located in the armpit or under the breast in order to eliminate an incision in the neck. This technique however is extremely invasive, requiring a lot of complicated dissection, has a steep learning curve and has little to recommend it.

5. Minimally Invasive Radionucleotide-Guided Parathyroidectomy (MIRP)

This method is popular in a very limited number of centres, but the enthusiasm for its use has not been shared by the majority of endocrine surgeons. It uses the affinity for the majority of parathyroid tumours to selectively take up Sestamibi. A high dose of radioactive Sestamibi (up to 20 mCi ^99MTc) is given an hour or so before the surgery and the tumour is detected using a hand held gamma probe. There is no evidence that outcomes are any better with this technique compared with scan-localised MIP.  

6. Approach to Mediastinal ectopic parathyroid tumours

Fig.5: Manubriotomy (split of upper part of sternum) to reveal parathyroid tumour in the chestOccasionally parathyroid tumours migrate out of the neck and into the chest (or mediastinum). It is rare to need to open the chest (less than 2%) to remove a parathyroid tumour, because the majority can be removed through a cut in the neck and pulling up the thymus gland, which often will have an elusive parathyroid tumour in its substance.

Sometimes this does not work and it is necessary to look in the chest by splitting the upper part of the breast bone (Fig. 5). This is rarely done at a first operation without thorough localisation, and is usually done after arteriography and venous sampling at a second operation.

My favoured method is to split the upper half of the breast bone (manubrium), which gives excellent access to the chest and limits pain and discomfort post-operatively. Patients recover quickly and have a stable breast bone, allowing earlier mobilisation and easy pain management. Very rarely parathyroid tumours lie below the arch of the aorta and must be removed by a left lateral thoracotomy (open chest surgery) or thoracoscopic mediastinal parathyroidectomy - please see below).

7. Thoracoscopic excision of mediastinal parathyroid tumours

This technique is not commonly used, with only 75 cases reported in the literature. Under general anaesthesia endoscopic ports are placed between the ribs and a thoracoscope (telescope) inserted with special instruments. The lung is allowed to collapse and the parathyroid removed before reinflation, and a small chest drain is left for up to 48 hours.

The aim of this method is to reduce post-operative pain compared with open thoracic surgery, but the British National Institute of Clinical Excellence issued guidance in December 2007, suggesting there was limited evidence to support thoracoscopic excision of mediastinal parathyroids. Central parathyroid tumours below the aortic arch are very rare and open surgery is very safe with little risk of danger from torrential bleeding due to aortic arch damage, something very difficult to control in endoscopic surgery.