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.I am 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 patients a year.
It is my 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! Using IOPTH, Mr Lynn's Group reported in 2009 to the BAETS a 98.6% cure rate in 268 sequential patients.In 2010 a Swedish group of surgeons confirmed Mr Lynn's results (Hessman Oet al British Journal of Surgery 2010;97 177-184)
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 operationsdue to a lack of surgical experience of 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 the large volume of re-do thyroid and parathyroid surgery and the regular use of intra-operative recurrent laryngeal nerve monitoring this is not Mr Lynn's experience.One is never complacent! In March 2009 Mr Lynn explored a patient who had two previous attempts at parathyroidectomy,Mr Lynn was unable to find the left recurrent laryngeal nerve because of dense fibrosis in the left neck.The patient developed a left recurrent laryngeal nerve palsy.Prior to this case Mr Lynn and co-workers published a review of 85 patients who underwent re-do parathyroidectomy from 1998 to 2007 demonstrated a temporary recurrent palsy rate of 3.5% and a permanent nerve injury rate of 0%.Nerve monitoring was used,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 or her method, sticks to it and performs a least 20 or more parathyroidectomies a year.Overall the results in the hands of real experienced surgeons are very similar whichever method is used.Despite this,I feel that pre-operative localisation of the parathyroid is now so accurate that an attempt to image the parathyroid tumour or tumours should be made in all cases prior to surgery.I would change the old adage that the only localisation necessary if you have a parathyroid tumour is the localisationof an "experienced parathyroid surgeon" to that of an "experienced parathyroid surgeon who always performs pre-operative localisation".
There are eight quite distinct ways of performing a parathyroidectomy.All eight 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 anaesthetic 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 now 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 (IOPTH) 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. I first used this approach in 1984 using the sestamibi scan.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..Intra-operative monitoring of the nerve is always performed. Usually the normal ipsilateral gand is also seen.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. Some surgeons are happy if the IOPTH falls by 50%. I do not accept this and will wait till the IOPTH falls to the lower end of the reference range. 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 contralateral smaller second adenoma ("silent adenoma") whose function is suppressed 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.This method is now the most widely used in the UK.It has been shown to be associated with a better perception of patient quality of life using the SF-36 A Health Questionaire.
#3. Video Assisted Minimally Invasive Parathyroidectomy.
This uses a small incision with 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 is higher than our own open method.
I 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 support mainly in France.The equipment is expensive and it use is limited to small parathyroid tumours less than 3 cms in diameter (In fairiness the majority of tumours).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 but not dangerous.
The view at surgery is superb, 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 a second operation very difficult.
#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 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 difficult 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 method and has the disadvantage of the use of radioactivity in the operating theatre!
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.This is because the majority can be removed through a simple cut in the neck, 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). This 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. Thoracoscopicexcision of mediastinal parathyroidtumours.
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, anda small chest drainis left for up to 48 hours.
The aim of this methodis to reducepost-operative paincompared with open thoracic surgery. NICE issued guidance in December 2007, suggestingthere 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. NICE stated that if there is a suspicion of parathyroid malignancy thatthis 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.
#8. Transaxillary Surgical approach
This technique has been been developed in Japan where for cultural reasons even an almost invisible scar in the neck is considered abhorrent. It has been marketed as a scarless operation but it is not since there is a scar in the armpit. The method is a complex way of treating a simple problem. The dissection from the armpit to the neck is extensive and if there is need for more than one gland to be removed the neck will need to be opened,defeating completely the object of the exercise.!Conversion rates of minimally invasive parathyroidectomy to open surgery of up 25% have been reported even when pre-operatively the parathyroid is said to have been well visualised. This data in itself is an argument against the axillary approach. It must be remembered that the surgery can be done very safely in most cases through an almost invisible 2cm cut.There is a modification of the technique. This is the so called "Robotic-assisted Parathyroidectomy". It is important that patients are not mislead by what superficially appears to be an advance. Here four incisions are used,three in the armpit and one below the collar bone.Most endocrine surgeons i have met feel these" non anatomical approaches" are not justified because they are aware that although most parathyroidectomies are easy to do up to 20% may be very tricky.If one was unlucky enough to be the patient with the tricky parathyroidectomy such methods could spell disaster. One concern is if there is bleeding in the neck hours after the surgery management may well be impossible. The use of robots is exellent were access to an organ is difficult such as in the case of prostatectomy but most be considered in the neck experimental and not necessary or even dangerous.Robotic parathyroidectomy is totally unnecessary! In the future there may be a role for telerobotic surgery in cases of neck malignancy were the robot is linked real time to CT or MRI scanners.This might allow a safe removal of a cancer with the preservation of normal tissues.If the patient is offered a non anatomical operation Mr Lynn's advice in the UK is to refuse and opt for one of the more proven and less invasive methods.
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.