Thyroid Ablation: The Procedure Day, from Preparation to Follow-Up

Ablation aims to render the nodule inactive in place rather than removing it surgically. Under ultrasound guidance a fine needle is placed inside the nodule; energy delivered from the tip heats the target tissue, which loses its viability. Over time the body shrinks that area.

The heat-based methods are radiofrequency ablation, microwave ablation and laser ablation. Among these, radiofrequency is the most widely used and the one assessed in most detail in the guidelines.

In predominantly fluid nodules a different route is taken instead of heat: the fluid is drained and ethanol ablation is then performed. Which method is chosen is decided by the structure of the nodule on ultrasound.

The first step is a detailed ultrasound assessment. The size of the nodule, its internal structure, its position within the thyroid and its relationship to neighbouring structures such as the recurrent laryngeal nerve, the oesophagus and the trachea are all established here. The plan is built on this examination.

The second is thyroid hormone testing. TSH, and other levels where needed, show whether the gland is over- or under-active.

The third is needle biopsy. Because ablation does not remove tissue, no pathological examination is possible; the nodule must therefore be documented as benign before the procedure. In international practice this confirmation is often made with two separate biopsies.

Scintigraphy, by contrast, is not a routine test. It is requested if the TSH is found to be low or if a nodule producing excess hormone (functioning autonomously) is suspected; by showing whether the nodule takes up iodine it can change the treatment plan. If the TSH is normal, most patients do not need it.

Any medication you take — blood thinners in particular — must be reported before the procedure; some of these may need to be paused temporarily.

The procedure is done in an ultrasound room rather than an operating theatre. You lie on your back with the neck tilted slightly backwards. After the skin is cleaned, local anaesthesia is given at the entry site.

In most patients a cool fluid containing dilute dextrose is then injected around the nodule. This is called hydrodissection; the aim is to place a cushion of fluid between the nodule and the neighbouring nerves and organs to protect them from the heat. Dextrose is preferred over saline for this, because saline conducts electrical current and can interfere with radiofrequency delivery.

A special needle with an active tip is then placed inside the nodule under ultrasound guidance and energy delivery begins. The energy is not applied from a single point; the nodule is divided into small parts and treated step by step, with the needle tip kept continuously visible on the screen.

You are awake throughout and your physician speaks with you at intervals. This is not small talk but a safety measurement: a change in your voice can be an early warning that the nerve to the vocal cord is being approached. You may feel warmth and pressure in the neck; additional anaesthesia is given whenever you feel uncomfortable.

The procedure usually takes between half an hour and an hour. Because no X-rays are used, you are not exposed to radiation.

In nodules whose content is largely fluid, the fluid is first drained with a needle. Drainage alone is often not lasting; the cavity can refill. For that reason ethanol is then delivered to the wall of the cavity to try to prevent fluid from reaccumulating.

In mixed nodules a two-step plan is built: the fluid component is addressed first, and thermal ablation is then considered for the remaining solid part. These two steps are sometimes done in the same session and sometimes in separate ones.

After a short observation period you go home the same day. For the first twenty-four hours it is advised to avoid heavy physical activity, pressing on the treated area and firm massage.

Tenderness, mild swelling and sometimes bruising in the neck are expected findings and settle within a few days. If there is pain, the analgesic your physician recommends may be used; a cold pack over the area also helps.

Eating soft, lukewarm food in the first days is more comfortable for most patients. This is a comfort suggestion, not a requirement.

The common side effects are temporary: pain in the neck, redness of the skin, swelling and mild bruising. These usually resolve on their own.

Rare complications include bleeding, a haematoma in the neck, hoarseness, and injury to a neighbouring nerve or vessel. Hoarseness is temporary in most cases; it arises from the proximity of the heat to the nerve and improves over weeks.

Disturbance of thyroid hormone balance, involvement of the parathyroid glands and a low blood calcium level are expected far less often here than after surgery, because the healthy thyroid tissue and the parathyroid glands are left in place.

In comparative studies, injuries to neighbouring structures related to the procedure have been reported less often in ablation patients than after surgery. Even so, this does not mean there is no risk — which is why the operator’s experience and correct patient selection are decisive.

The nodule does not disappear at once. Shrinkage proceeds gradually over months and generally settles towards the end of the first year; this course is followed with ultrasound.

Check-ups are usually planned at 1, 3, 6 and 12 months. At each one the volume of the nodule is measured, the appearance of the remaining tissue is assessed, and thyroid hormone levels are checked where needed.

Having the follow-up ultrasound performed, where possible, by the radiologist who did the procedure and compared against the pre-procedure images makes the assessment more reliable. Measurements can differ between machines and between operators; keeping the comparison on one line matters for that reason.

Large nodules may need a second session for sufficient shrinkage. A small remaining residue can also grow again over the years; this possibility, like the possibility of recurrence after surgery, is known from the outset and is followed up.

Contact them without delay if there is rapidly increasing swelling in the neck, difficulty breathing, marked difficulty swallowing, fever, or a change in the voice that does not resolve.

Pain more severe than expected and not relieved by an analgesic should also be assessed. Most of these findings are not a sign of a serious problem, but having them looked at early is the right course.