Parathyroid Surgery - Introduction
This section contains information on the details of parathyroid surgery including, the tests done before surgery and what the various operations involve.We are convinced that no parathyroid tumour patient should be explored without pre-operative scans and that the surgery should be performed by a surgeon who operates on at least 20 parathyroid cases a year.
It is our view that the success of parathyroid surgery is directly related to the yearly volume of the surgeon.The BAETS audit in 2007 demonstrated that in the UK only 17 surgeons performed more than 20 parathyroidectomies a year (in our view the minimum number to maintain surgical skills),43% of BAETS members performed 10 or less parathyroidectomies, while a staggering 21% performed less than 5 cases a year.
Mr Lynn is convinced that intra-operative parathyroid hormone (IOPTH) measurement is essential.Some units claim its too expensive and not cost effective! Dr Charles Zammit in Brighton in the UK has been to managed to use existing biochemical facilities for IOPTH.Using the routine laboratory he has a turn round time of 30 minutes at a cost of 6 euros for each blood test.A small price to pay for improved results.Don't have or do a parathyroidectomy without IOPTH!
The patient undergoing parathyroidectomy should enquire about their surgeon's experience and note that being a member of the BAETS does not in itself imply special skills in parathyroid surgery.This is a controversial view, but one which is confirmed by Mr Lynn's extensive experience in redo parathyroid surgery.Patients who have had failed surgery elsewhere have usually had unsuccessful operations due to a lack of surgical experience by the initial surgeon.Despite the difficulty of re-operation,Mr Lynn reported in 2008 a 97.2% success rate for second operations.Like all surgery, parathyroid surgery has no place for the enthusiastic amateur!
If a patient needs a second operation the audited 2007 BAETS risk of nerve damage rises four fold.Due to our large volume of re-do thyroid and parathyroid surgery and our regular use of intra-operative recurrent laryhgeal nerve monitoring,this is not Mr Lynn's experience.Nerve monitoring a practice is not widespread with BAETS members.
The parathyroid patient tends to be confused by the various surgical methods. The golden rule is to choose a surgeon who is expert at his method and performs a least 20 or more parathyroidectomies a year.Overall the results in the hands of experienced surgeons are very similar whichever method is used.Despite this, we feel that pre-operative localisation of the parathyroid is now so accurate that an attempt to image the parathyroid tumour should be made in all cases prior to surgery.We would change the old adage that the only localisation necessary if you have a parathyroid tumour is the localisation of an "experienced parathyroid surgeon" to that of an "experienced parathyroid surgeon who always performs pre-operative localisation".
There are seven quite distinct ways of performing a parathyroidectomy.All seven methods will be discussed in detail and their advantages and disadvantages highlighted.
#1. Traditional Open Parathyroidectomy
This is how parathyroid surgery was first done and has stood the test of time for 80 years. It is usually done under general anaaesthetic and involves looking at all 4 parathyroids.It was developed long before intra-operative parathyroid hormone measurement was available.When pre-operative localisation has failed or has not been done it is the procedure of choice.We have had considerable experience of this method but only use it when we are unable to pre-operatively localise the parathyroid abnormality, localisation suggests multiple gland disease, or in the rare circumstance of parathyroid cancer.We also use it when we have removed a localised parathyroid tumour and the PTH level during the operation does not fall to normal.
Our overall result using this method is a 98% cure rate.Why then do we not use it all the time? The reason we limit its use to only 20% of cases is that the combination of pre-operative scans and the use of intra-operative PTH measurement allows us to cure the majority of cases using a small 2cm incision and not the 10cm incision of the traditional method.Reducing the size of the incision reduces pain and shortens hospital stay.
#2. Scan-Directed Minimally Invasive Parathyroidectomy
In the 1980s Sten Tibblin pioneered a unilateral approach, and it is now our method of choice in the 80% of cases where we have localised the parathyroid tumour pre-operatively.It is very simple and can be done under local anaesthetic,with a small incision made over the abnormal gland to be removed.Intra-operative monitoring of the nerve is always performed.Our pathologist checks that the tumour is indeed parathyroid tissue, and the level of parathyroid hormone is checked and if it returns to normal the procedure is completed.If there is any suggestion that there are further tumours then we convert to a traditional 4 gland exploration.There is one "catch" with this technique.Sometimes there is a small contralateral smaller second adenoma whose function is supressed at the time of surgery. Days,months or years later this adenoma may start to function and cause persistent or recurrent hyperparathyroidism.All is not lost, since re-evaluation with scans will locate the second tumour.This a rare event, a second scan directed parathyroidectomy will cure the patient.
It has been shown that minimally invasive scan directed paathyroidectomy is associated with a better perception of patient quality of life using the SF-36 A Health Questionair.
#3. Video Assisted Minimally Invasive Parathyroidectomy.
This uses a small 2.5cm central neck incision and is very similar to our own open technique. To aid the surgery a 30 degree telescope is used and the surgery is performed while observing progress on a television monitor.We have used this method, but if the gland is well localised it has little advantage over our own technique except that it allows visualisation of all 4 parathyroid glands through the 2.5cm incision.The method has quite a sharp learning curve and its complication rate may be higher than our own open method.
There is one area where we think this method should be considered: when the parathyroid tumour is in the upper chest and considered impossible to remove by the traditional or our own open method.In these circumstances removal of the tumour can be performed using the video assisted technique without the need to split the breast bone (sternum).
#4. Endoscopic Parathyroidectomy
This method is a purely endoscopic method and for a bilateral exploration needs at least 5 small cuts in the neck.It has never been popular in the UK or the USA, but has its support mainly in France.The equipment is expensive and it use is limited to small parathyroid tumours less than 3 cms 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 re-operation is necessary there is a vaste amount of fibrosis making the second operation very difficult.Some surgeons are attempting to perform endoscopic parathyroidectomy through small incisions in the armpit, but we think this has no merit and condemn it completely.
#5. Minimally Invasive Radionucleotide Guided Parathyroidectomy. (MIRP)
This method is popular in a very limited number of centres,but the enthusium for its use has not been shared by the majority of endocrine surgeons both in the USA and Europe.It really is an extension of our own method but 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.The parathyroid tumour contains about 59% of the radioactvity as compared to 9% in non parathyroid tissue.The method is very useful where facilities for intra-operative pathology are difficuly to obtain (frozen section).In the past we have used this method and came to the conclusion that it had little to add to our favoured methods and has the disadvantage of the use of radioactivity in the operating theater!
We have however noticed that it may have some advantage in patients whose initial sestamibi scan is negative.This comment may seem paradoxical but the very high dose of radioactivity at surgery may highlight the tumour on the gamma probe even though it was not seen on the pre-operative low dose sestamibi scan.
#6. Open thoracic approaches to ectopic parathyroid tumours.
It is very rare to need to open the chest to remove a parathyroid tumour, because the majority can be removed through a simple cut in the neck and pulling up the thymus gland which so often has a tumour in its substance.Sometimes this does not work and it is necessary to look in the chest by splitting the breast bone.We have developed a method of only splitting the upper half of the breast bone (manubrium), which gives excellent access to the chest and limits discomfort post-operatively.We reported this method to the BAETS in the summer of 2007.Very rarely parathyroid tumours lie below the arch of the aorta and can 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 rarely used, there being only 58 cases in the English and French literature by December 2007.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 NICE 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 (only 3 in over 2000 cases in our own experience) 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.NICE also stated that if there is a suspicion of parathyroid malignancy that this may influence the choice of surgical procedure, but we would suggest that if malignancy is suspected an endoscopic procedure should not be performed as the risk of direct invasion of the aorta is significant.
There is an excellent review of all types of parathyroid surgery, which is very clear and although written for the medical profession is suitable reading for the general public. The reference is:-
Antonio Sitges-Serrs et al: Surgery for sporadic primary hyperparathyroidism: controversies and evidence based approach.Langengbecks Arch Surg (2008) 393: 239-244.
Please note that some parts of the parathyroid section are written in detail for surgeons and include pictures of surgery that some people may not wish to view.
