Thyroidectomy: positioning, incision and initial exposure
THE CONTEXT
Thyroidectomy aims to remove the entire affected lobe, or both lobes for total thyroidectomy, while preserving surrounding structures and minimising cosmetic impact.
Structures to preserve
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Preserve the cervical strap muscles, external branches of the superior laryngeal nerve, recurrent laryngeal nerve, parathyroid glands and parathyroid blood supply while encompassing all disease.
Positioning and preparation
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Under general anaesthesia, position the patient supine with arms at the sides and the head on a ring. Extend the neck using a shoulder roll or table adjustment, with the head of the bed raised in reverse Trendelenburg.
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Prepare the operative field from the lower lip to the upper chest.
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A nerve-monitoring endotracheal tube or electrode wrap may be used. Check tube position after positioning because neck extension can withdraw the tube and compromise laryngeal electrode contact.
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Nerve monitor leads can be included in the head drape. Squaring off the surgical site offers easier access to the endotracheal tube if needed.
Incision and exposure
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Place the incision in a skin crease close to the cricoid at the superior edge of the thyroid isthmus. Its length depends on gland size, with little benefit from extending much beyond the medial edge of the sternocleidomastoid.
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Mark the incision before preparation and infiltrate local anaesthetic with adrenaline. Use a scalpel through the skin and dermis along the full incision.
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Monopolar diathermy may expose and divide the platysma. Raise subplatysmal flaps to the thyroid notch superiorly and the suprasternal notch inferiorly.
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Identify the midline between the strap muscles superiorly. Raise sternohyoid with toothed forceps and divide the fascia using monopolar diathermy while avoiding the anterior jugular veins.
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A Langenbeck retractor assists dissection at the superior and inferior limits.