INTRODUCTION

At one time, thyroid disease, particularly in the form of marked enlargements and over activity, was only curable by surgical treatment. Indeed, the Nobel Prize in medicine was awarded to Professor Theodore Kocher of Switzerland in 1909 for making thyroidectomy a safe procedure. In the last 50 years, medical discoveries regarding the thyroid gland have been numerous and have resulted in decreasing the need for surgical treatment. However, surgical treatment is still an essential part of the treatment of many thyroid conditions.

PREOPERATIVE INVESTIGATION

Enlargements or dysfunctions of the thyroid gland can be so varied in nature that patients with these problems must undergo appropriate investigation to make a proper diagnosis. The tests usually consist of thyroid function tests, radioactive thyroid scans, thyroid ultrasound and most importantly, Fine Needle Aspiration Biopsy (FNAB) of the thyroid gland. Based on the results of these tests, along with a suitable history, a doctor may refer the patient to see a surgeon to determine whether surgical treatment is appropriate or helpful in a particular situation.

INDICATIONS FOR SURGERY

Surgical treatment is particularly recommended for those patients with nodules that are considered cancerous. This is primarily detectable by FNAB. While FNAB can detect cancerous tissue, it more frequently reports malignancies as showing “cellular” or “follicular” lesions. Even though FNAB diagnosis may not indicate a strictly cancerous diagnosis, it may indicate a diagnosis that is sufficiently suggestive of cancer to warrant surgical treatment.

Patients with an overactive thyroid enlargement may require surgical treatment. This is particularly true for those with nodules in the thyroid gland either solitary or multiple. It is less likely for patients with Graves’ disease to require surgical treatment. However, patients with a bulky enlargement, Graves’ disease with an associated solitary nodule which is cold on scanning or the rare patient that needs rapid control of hyperthyroidism, may all be eligible for surgical treatment. Patients with Graves’ disease that have important eye disease, do not respond to antithyroid drugs. In some cases, the eye disease is aggravated by the administration of radioactive iodine. These patients may also be reffered for surgical treatment.

Patients who have experienced radiation of the head and neck area, may develop a nodularity of the thyroid gland which may require surgical treatment. Particularly if there is 30 to 60% chance of cancer in such glands. In Canada, the usual indication for such radiation was the treatment of acne, blood vessel tumours of the facial skin or occasionally an “enlarged thymus.” Other patients received radiation as part of treatment for head and neck cancer or lymphoma.

Patients on occasion may develop an enlargement of the thyroid gland to the extent of pressure on the windpipe. This pressure may cause the patient to have the feeling it is hard to swallow or have difficulty breathing. This can be verified on x-ray examination of the chest where the windpipe can be seen to be deviated by the enlarged thyroid gland. In this situation surgery is effective and may be preferred.

COURSE IN HOSPITAL

The patient requiring thyroid surgery is usually admitted to hospital after suitable preoperative testing which may include a chest x-ray, an electrocardiogram, and various blood tests including thyroid function tests. The surgical treatment is carried out through a relatively short incision in the lower central portion of the neck.

The thyroid gland is made up of two symmetrical lobes. Where there is an enlargement of both lobes, malignancy or Graves’ disease, removal of most of the thyroid gland may be required.

In some situations, only a portion or a half of the thyroid gland requires removal and this is particularly true of benign conditions.

If cancer is present in the thyroid gland, the surgeon should make a search for a spread of cancer to lymph nodes of the neck. If the lymph nodes of the neck are involved, they may require removal by an operation called a modified neck dissection in which there is a minimal derangement of function and appearance. The thyroidectomy incision may have to be extended along the lower neck in order to enlarge the exposure of the neck to carry out such a neck dissection.

The central muscles of the neck are parted and the lobe of the thyroid gland is removed after careful dissection. The removal involves the recognition and preservation of the superior laryngeal nerve, and the recurrent laryngeal nerve, both of which go to the vocal cord, and parathyroid glands. These control the level of calcium in the body.

Following operation, the incision is stitched carefully and the patient usually can be discharged on the first or second day following surgery. Sutures can be removed by the second postoperative day and the patient is expected to return to the surgeon a week following surgery for further assessment. Some centres offer thyroid surgery as a day-surgery. New video-assisted techniques, slightly less invasive, are also performed in specific circumstances, usually for benign conditions.

SIDE EFFECTS OF OPERATION

Immediately after surgery, the patient may experience a swelling of the neck in the area of the incision, a sore throat, some difficulty in swallowing, and some discomfort at the back of the neck from the position during surgery. All these problems are usually of moderate degree and disappear after days or after a few weeks.

Occasionally, fluid will build up underneath the incision and the surgeon will have to drain this with a needle and syringe. This is easily managed and is unnecessary to open up the incision to drain any fluid collected. Infrequently there will be some change of the voice This is usually due to a form of laryngitis following irritation by the anaesthetic tube. This should disappear in a few weeks or even months time. While an injury of the recurrent nerve can cause hoarseness or weakness of the voice, this is an unusual event and should be completely avoidable. Occasionally with cancerous conditions, the recurrent nerve is destroyed by the cancer, and its loss is unavoidable if the malignancy is removed completely.

Where most of the thyroid gland is removed, the occurrence of a low calcium state following such surgery is not uncommon and is easily treated by calcium supplement. This is usually self-correcting although it may take a few weeks or months before the calcium state returns to normal and pills are no longer necessary. Occasionally calcium pills must be taken on a permanent basis, and this is particularly true for extensive cancers of the thyroid gland that require excessive manipulation of the gland. This is due to damage of the parathyroid glands during surgery.

The incision as a rule heals very nicely and is cosmetically very acceptable. Scarring may be more evident in people of Oriental, Black origin or in adolescence. This can be treated with cortisone injection and is usually an effective improvement.

POSTOPERATIVE TREATMENT

Following surgery, replacement treatment with thyroxine is mandatory for all patients whose entire thyroid gland was removed and for some patients with partial thyroidectomy.

If a patients’ condition is that of a cancer, he/she may require treatment with radioactive iodine. This depends on the final report of the tissue examined by a doctor called a pathologist. The patient’s doctor should make recommendations regarding such treatment.

It is important that all patients undergoing thyroidectomy have a follow-up of their thyroid function tests. Taking a thyroid pill is a simple matter and does not require complicated control. Patients with malignancy may be seen more often and require ultrasound examinations of the neck. Thyroglobulin tests should also be done to detect possible recurrence of cancer. If the levels of calcium were made permanently low, then calcium and Vitamin D must be administered and monitored.

OPERATIVE RESULTS

Patients undergoing thyroidectomy usually recover quickly and well with little to show as a rule for their operative experience. The side effects of the surgery should be minimal, and it is best to ensure that the surgeon selected for the operation is someone who is experienced or educated in thyroid surgery. The treatment of malignancy by surgery in particular is exceptionally effective, and the cure rate is exceptionally high. Patients should enjoy a sense of good health and vigour following their recovery from thyroid surgery.

Updated in May 2010 by Hortensia Mircescu, MDFRCPC, Endocrinology Division, Centre Hospitalier de l’Université de Montréal, Assistant Clinical Professor, Faculty of Medicine, Université de Montréal from the original text written by: IrvingB.Rosen, MD., FRCS(C), FACS, Professor of Surgery, University of Toronto, Department of Surgery, Mount Sinai Hospital; Consultant in Surgery, Princess Margaret Hospital, Ontario Cancer Institute and Paul G. Walfish CM, MD, FRCP(C), FACP, FRSM., Professor of Medicine, Pediatrics and Otolaryngology, University of Toronto; Senior Consultant, Endocrinology and Metabolism and Head and Neck Oncology Program, Mount Sinai Hospital.