Good head position allows adequate exposure. The neck should be in full extension with the shoulders elevated. The entire neck and chest should be prepared into the surgical field in case a more extensive exposure is quickly required. As with any neck scar, asymmetry leads to an unaesthetic result, and marking the intended site often results in a more pleasing closure. Make the skin incision about two fingerbreadths cephalad to the suprasternal notch. The incision need only be 2 to 3 cm long, enough to accommodate the mediastinoscope, extending only to the anterior borders of the sternocleidomastoid muscle. Carry the incision down by electrocautery through the subcutaneous tissue to the level of the strap muscles. Sizable veins (anterior jugular veins) can run in this tissue and may require formal ligation with silk ties. Identify the midline as a fine, pale yellow line. Incise this connective tissue with electrocautery or Metzenbaum scissors superiorly and inferiorly, and retract the strap muscles vertically. Divide the connective tissue of the midline by sharp dissection or electrocautery until the trachea is encountered. Incise the pretracheal fascia to allow access to the correct tissue plane, just anterior to the trachea itself.

When making the incision, the trachea will be exposed at about the same location as in tracheostomy, caudal to the thyroid. The inferior thyroid vein can often pass cephalad in the midline and requires careful mobilization and lateral retraction.

As the surgeon’s finger passes under the manubrium, the back of the aortic arch is palpated just as it gives off the
brachiocephalic (innominate) artery. Place a pulse oximeter on a finger of the patient’s right hand to monitor compression of this artery during the procedure.

Moisten your index finger with saline and carefully introduce it into the superior mediastinum, staying directly on the cartilage rings of the anterior trachea. Take care to keep the aspect of the finger (fingernail) against the trachea as a guide against dissection into the wrong plane. As the tip of your finger passes under the manubrium, palpate laterally. Enlarged deep scalene nodes will be palpable in this region, even if they were not appreciated on physical examination. Continue blunt dissection downward very gently, staying on the anterior aspect of the trachea and introducing your finger as far as it will reach. When the finger is fully introduced, the pulsations of the aortic arch (anterior to the left main bronchus) and brachiocephalic (innominate) artery takeoff (anterior and to the right of the midtrachea) are easily appreciated on the volar aspect of the finger. Careful palpation may identify lesions, but is rarely very accurate in predicting the yield with the mediastinoscope. Occasionally, an enlarged node will adhere to the dorsum of the aortic arch; careful palpation can help to determine whether biopsy of the node can be accomplished safely. Continued gentle blunt dissection with the finger should be undertaken to widen the channel to either side of the trachea. Never force areas of dense adhesion or induration because this can result in significant vascular injury and major bleeding.