Substernal Goiter Surgery Periprocedural Care

Adequate education about the diagnosis, ramifications, indications, and reasons for substernal thyroidectomy is a very important part of the clinical conversation between a treating physician and patient.

In addition, obtaining informed consent with an explanation of the steps of the operation, risks, benefits, and possible alternatives of the surgery is crucial.

Elements of Informed Consent

The example below illustrates the range of elements that are important for a surgeon to convey to a patient undergoing substernal thyroidectomy presented in language that minimizes the use of complex medical terminology as it might in a patient handout.

Steps of the operation

A substernal thyroidectomy involves the following steps:

1. Skin incision horizontally along the front aspect of the lower neck and possibly in a vertical fashion down the midline of the upper chest

2. Dissection through the tissues overlying the thyroid and along the circumference of the gland

3. Identification and/or avoidance of the parathyroid glands (two on each side), the superior and recurrent laryngeal nerves (on each side), and the major blood vessels in the neck and upper chest

4. Removal of a thyroid lobe or the entire gland

5. Potential vertical split of the sternum bone with a special surgical saw

6. Potential placement of a flexible plastic drain to remove excess fluid from underneath the skin flaps (to encourage proper healing)

7. Skin closure with sutures and possibly staples

Postoperative hospitalization

Patients who are in good health may be able to go home on the day of surgery in some cases. Some patients may need to stay in the hospital after surgery for 1-2 days.

Benefits of surgery

Benefits of the surgery should include the following:

• The removal and treatment (and reduction of recurrence risk) of benign or malignant tumors or an enlarged thyroid gland (ie, goiter)

• The resolution of compression of the trachea, esophagus, and/or major blood vessels, with the associated symptoms

• The resolution of hyperthyroidism and its symptoms

• Determination of the presence of cancer and the possible need for additional treatment

Alternatives to surgery

In some cases, waiting and observing with regular clinic appointments and possibly radiologic images is an option. For hyperthyroidism, medical therapy is still an option in some cases.

These issues should be discussed carefully between the surgeon and patient.

Risks/possible complications

All types of surgery carry some risk. Complications associated with substernal thyroidectomy surgery are rare (some very rare). Substernal goiters that require extensive dissection may be associated with a somewhat greater risk than standard thyroidectomy; ^[4] however, many surgeons and authors feel that the rate of complications associated with removal of substernal goiters is similar those associated with standard thyroidectomy. ^{[14, 12]} Under the care of well-trained surgeons, the benefits of surgery usually outweigh these risks and potential complications.

Potential risks are discussed below.

Low thyroid hormone levels in the blood (hypothyroidism): A thyroidectomy decreases or completely removes the body’s ability to make thyroid hormone (a hormone that helps to control the body’s function and metabolism). Thus, after a total thyroidectomy, the patient will need lifelong thyroid hormone replacement in the form of a pill that is taken daily. After a partial or hemithyroidectomy, the remaining gland is usually able to make a normal amount of hormone; however, further blood tests after surgery will determine the need for hormone replacement.

Unwanted scar: All incisions performed during surgery result in scars. Hypertrophic scars or keloids (overabundant scar tissue) that develop in some patients can often be treated.

Numbness: All patients who undergo thyroidectomy experience some numbness of the skin of the neck above and below the incision. Some sensation may return over months to years.

Sore throat due to intubation: Some patients develop a sore throat for the first few days after surgery from the breathing tube being in their throat during the operation. Rarely, the breathing tube may cause inflammation that lasts longer than a few days.

Low calcium levels: The parathyroid glands, which are located next to the thyroid gland, produce a hormone that maintains the appropriate amount of calcium in the blood stream. In some cases, surgery temporarily or permanently disrupts the glands’ function, leading to low blood levels of calcium, which can result in numbness and tingling around the mouth, hands, and feet and muscle spasms. Without calcium replacement, seizures and problems with the heart’s rhythm may develop. Low calcium levels are treated with calcium and possibly vitamin D supplements to restore the normal calcium balance. These medications are continued until parathyroid function improves. If parathyroid function does not improve with time, the patient may need lifelong calcium medication. Permanent parathyroid dysfunction is a rare complication. With hemithyroidectomy surgery (one thyroid lobe being excised), the risk of parathyroid gland dysfunction is extremely low.

Bleeding/hematoma: A collection of blood can develop under the skin flaps and may prolong healing. This is more common in patients who are taking blood-thinning medications (eg, warfarin, clopidogrel, aspirin, ibuprofen, naproxen). Treatment may involve observation, antibiotics, or a reoperation to open up the skin to remove the clot.

Seroma: A collection of fluid can develop under the skin flaps and may prolong healing. Treatment may involve observation, needle aspiration, or the sterile insertion of another drain to release the fluid.

Infection/abscess/bone infection: Treatment may involve antibiotics and, possibly, an incision to drain a pus collection.

Recurrent laryngeal nerve injury: This injury (temporary or permanent) is a rare complication that can result in partial or complete paralysis of the vocal cord on the side of the injury. This can cause a breathy or hoarse voice and possible aspiration of secretions into the lungs. Often, the other vocal cord acts more strongly to maintain the voice and lung protection. Vocal cord function can return in many cases over a few weeks to several months. If injury is prolonged or permanent, the vocal cord can be injected with a material to increase its bulk, allowing more appropriate vocal cord closure and better voice quality.

Superior laryngeal nerve injury: This injury (temporary or permanent) is a rare complication that can result in partial or complete paralysis of the cricothyroid muscle. This can cause some speech and singing problems. Function can return in many cases over a few weeks to several months.

Chest bone fracture: Breaking one or more of the chest bones is rare but possible with the split of the sternum. Usually, any breaks heal on their own without treatment beyond pain control.

Sternum disfigurement: Rarely, a shift of the closure of the sternum split can result in a raised portion of bone or an asymmetrical appearance of the bone. This may or may not need treatment.

Sternum dehiscence: Complete separation of the closure of the sternum split is very rare. This is an emergency that requires a return to the operating room for reclosure.

Pneumothorax and/or pneumomediastinum: Air can develop in the chest and/or around the lungs as a result of uneventful surgery or more rarely from a lung injury. If the amount of air is small enough, the air can be observed without treatment with the expectation of full reabsorption. If there are symptoms of difficulty breathing or chest pain and/or the amount of air is large enough, a catheter or tube may need to be inserted through the skin into the chest to evacuate the air.

Prior to surgery, the patient should be advised of the steps of the operation and recovery, risks, benefits, and possible alternatives.

Preoperative management should include reducing the risk of thyroid storm through medical evaluation and treatment, preparation for possible airway difficulties during intubation, and a thorough comprehension of the anatomic aspects of the particular patient being treated for appropriate surgical planning.

All patients undergoing any thyroid surgery should undergo preoperative thyroid function studies and appropriate medical management of any thyrotoxicity.

Intubation can be more challenging with distortion of the position of the larynx, narrowing of the trachea, and changes to expected anatomy with neck extension. ^[42] Therefore, a preoperative evaluation by the anesthesia team and a discussion between the surgeon and anesthesiologist regarding airway management should be undertaken. The anesthesiologist should be prepared to perform a fiberoptic intubation, if indicated, to ensure successful intubation. ^[65]

Consultation with and the availability of a surgeon with expertise in midline sternotomy are important to ensure that the proper exposure is possible for the substernal goiter. Poor exposure in the mediastinum can lead to damaging complications in substernal thyroidectomy. ^{[4, 66, 47, 63, 24, 6]}

Preoperative clearance by a primary care physician and/or cardiologist, pulmonologist, or other specialists should be obtained, when necessary. If possible, patients should discontinue blood-thinning agents such as aspirin, naproxen, ibuprofen, clopidogrel, and warfarin.

Equipment involved in substernal goiter surgery includes the following:

• Tegaderm for eyes

• Head rest

• Shoulder roll

• Laryngeal nerve monitor endotracheal tube (this is recommended by some surgeons and authors to help identify and assess for inadvertent manipulation of the superior and recurrent laryngeal nerves)

• Nasogastric tube to help identify esophagus intraoperatively with palpation

• Foley catheter

• Head lights

• Ink marker

• 1% lidocaine/1:100,000 epinephrine

• Chlorhexidine soap

• Split drapes

• No. 15 blade

• Elastic hooks for skin flaps

• Multiple forceps, dissectors, clamps, scissors, and retractors of various sizes and angles

• Sharp rakes

• Double-pronged skin hooks

• Suction

• Unipolar cautery (paddle tip)

• Bipolar cautery (jeweler and/or bayonet)

• Ligation device

• Automatic surgical clip applier

• Cotton pledgets with epinephrine 1:1000 for topical use only (with yellow fluorescein to reduce risk of injection)

• 7-10F flat Jackson Pratt drains

• 3-0 nonabsorbable monofilament sutures

• 2-0/3-0 silk free ties (multiple)

• 3-0 absorbable multifilament suture on pop-off-tapered needles

• 4-0 absorbable monofilament suture on tapered needles

• 5-0 nonabsorbable monofilament suture

If midline sternotomy is performed, additional equipment is as follows:

• Sternotomy saw

• Sternotomy self-retaining retractor

• Bone wax

• Vessel loops

• Sternal wires (for closure of sternum)

Anesthesia

General anesthesia is used for this procedure. Paralysis is not used to allow for laryngeal nerve monitoring (if used).

Awake oral or nasal fiberoptic endoscopic intubation with topical local anesthesia should always be considered in cases involving oropharyngeal, laryngeal, or tracheal abnormalities (eg, laryngeal deviation, vocal cord paralysis, tracheal compression).

Laryngeal nerve monitoring tube may be used during the operation.

Positioning

The patient is placed in the supine position with arms padded and tucked.

The head of the bed is slightly raised to encourage venous return and to allow fluids to flow in an expected direction during dissection.

Some surgeons operate with the head of bed at the anesthesia station; others prefer a 180° turn.

During the hospitalization, the following issues should be managed by the surgeon:

• Pain control: Acetaminophen, low-dose opioid orally and/or intravenously, as needed

• Nausea control: Antinausea medications intravenously, as needed

• Drain output: Monitoring and removal when output is low enough

• Antibiotics, depending on the surgeon’s judgement and preferences

• Moisturization of the wound

• Thyroid hormone (levothyroxine) replacement with starting dose dependent on the patient’s weight, age, and other medical problems

• Deep venous thrombosis prophylaxis during the hospitalization with sequential compressive devices, regular ambulation, and possibly subcutaneous heparin or enoxaparin determined by the surgeon’s judgement and preferences

• Incentive spirometry to help encourage lung inflation

• Monitoring perioral and digital (fingertips and toes) paresthesias as an indication of possible low blood calcium levels

• Blood tests for calcium (and possibly albumin and PTH), as determined by the surgeon’s judgement and preferences

• Replacement of calcium and/or vitamin D, as determined by the surgeon’s judgment and preferences

If a midline sternotomy is performed, the following additional measures should be taken:

• Chest radiography to evaluate for possible pneumothorax/pneumomediastinum

• Movement restrictions to allow sternum to adequately heal

Follow-up

The patient is usually seen 7-10 days after surgery for a wound check, possible suture removal, possible vocal cord examination, possible final pathology report discussion, and possible blood calcium test.