Fig. 4.1
Preoperative patient’s position. Rolled towels are positioned between the shoulder blades to obtain neck hyperextension
An iodine-based solution was used to prepare the surgical field and sterile drapes are placed, leaving an opening over the surgical site.
Local anaesthesia with 1 % lidocaine and epinephrine is performed, in order to reduce bleeding. A 2–3 cm transverse skin incision is created; it is very important to pay attention during the dissection of the deep layers to prevent lacerating the superficial vein or thyroid isthmus (Fig. 4.2). Then by means of a vertical dissection, the infrahyoid muscles were retracted to access the trachea (Fig. 4.3).
Fig. 4.2
The skin incision should be conducted carefully to avoid damaging the subcutaneous vessels that join the anterior jugular veins in the midline
Fig. 4.3
Subcutaneous vessels must be highlighted and tied to access the pretracheal muscle
Hemostasis is achieved progressively with bipolar forceps. At this stage when the thyroid isthmus appears, it is carefully cut and tied (Fig. 4.4). The isthmus of the thyroid may be divided. Tracheostomy through the divided isthmus provides direct access to the anterior surface of the trachea. However this makes the procedure much more invasive and the risk of haemorrhage is greatly increased. An alternative consists of retracting the isthmus downward (supra-isthmic approach) or upward (infra-isthmic approach).
Fig. 4.4
The thyroid isthmus appears after infrahyoid muscles retraction
An intact isthmus may increase the risk of secondary haemorrhage from erosion of small vessels in the isthmus by tracheostomy cannula; in addition the isthmus may move and obstruct the tracheal orifice, making it more difficult to change the cannula.