area roughly corresponds to the superior mediastinum, which extends from the thoracic inlet to an imaginary horizontal plane
between the angle of sternum and the T4 and T5 intervertebral disc. Immediately behind the sternum, the thymus lies embedded
in the loose areolar tissue.
lies the left brachiocephalic vein, which is formed by the confluence of the left jugular and subclavian vein and ascends
obliquely to join the right brcahiocephalic vein forming the superior venacava (SVC) at the first intercostal space. The SVC drains into the left atrium after descending behind the manubrium.
The vagus nerve
and phrenic nerve lie anterior to the arch of aorta. The vagus nerve descend into thorax posterior to the root of lung, and
gives the recurrent laryngeal nerve which on the left side loops around the aorta and ascends into the neck in tracheoesophageal
groove. The phrenic nerve descends in thorax in front of the root of lung to supply diaphragm.
The aortic arch gives rise to:
the brachiocephalic trunk on right side, the left common carotid, and the left subclavian arteries on the left side. The left
common carotid artery ascends into the neck in the carotid sheath along with the internal jugular and vagus nerve. The subclavian
artery enters the axilla behind the first rib to supply the upper extremity.
The thoracic duct enters the
superior mediastinum on the left side behind the aortic arch; it ascends between the left subclavian artery and the esophagus
before forming an arch 3 to 4 cm above clavicle and draining into the angle of junction of the left subclavian vein with the
left internal jugular vein.
The supra pleural membrane is
attached to the first rib superiorly and peripherally, and to the investing layer encompassing the mediastinal structures
on the medial aspect. This dense facial layer projects about 2cm above the clavicle and covers the lung apex and its pleural
The patient is positioned supine with a pad of rolled towel placed in between the scapulae. A gardener
well’s tongs may be placed if extension or distraction is contemplated. The head should be turned to the opposite side
and the shoulders can be pulled down and strapped with adhesive tapes. This helps in taking intraoperative radiographs.
A left sided approach is preferred as recurrent laryngeal nerve on this side has a more consistent
Incision: The incision is made along the anterior border of left sternocleidomastoid muscles to sternal notch and continued
in the midline to level of 3rd costal cartilage. The platysma is spilt in line with its fibers along with the fascia
on the anterior border at sternocleidomastoid. Beneath the medial border of the sternocleidomastoid, the carotid artery in
the carotid sheath can be palpated. The sheath contains the common carotid artery, the internal jugular vein and the vagus
nerve. The plane between the carotid sheath laterally and trachea and esophagus medially is easy to develop by blunt dissection
after tenotomy of the omohyoid. The inferior thyroid artery lies at the inferior pole of the thyroid gland and needs to be
divided after ligating.
Lower down in the thoracic part of exposure, the sternal fascia is incised and the strap muscles divided near their
origin from sternum to permit later reconstruction. The sternum is then divided in the midline from sternal notch to 2nd
intercostal space and laterally to the left through synostosis between manubrium and body of sternum. A small chest retractor
is placed and the partial sternotomy is opened.
and mediastinal fat are dissected away from the left brachiocephalic vein. The thoracic duct ascends to the left of the esophagus
from the level of T4 to its junction with the left internal jugular vein and subclavian veins. The cervical pleural
lies at about the T1 level, between the long muscles of neck and subclavian artery. The recurrent laryngeal nerve ascends
in the groove between the trachea and esophagus after looping around the arch of aorta.
All these structures must be identified before further dissection and preserved during the further course of dissection.
The deep prevertebral fascia is then divided in the midline and dissected laterally till the long
muscles of neck. Using a periosteal elevator the longus colli can then be elevated on both sides of anterior longitudinal
ligament until the base of transverse processes is reached on both the side.
The intervertebral disc is elevated and being softer than the surrounding vertebral body makes
its identification easier. The level can be confirmed by taking an intraoperative radiograph
Injury to any of following structure may occur:
Inferior thyroid artery, Recurrent Laryngeal nerve, Thoracic duct, vagus nerve, phrenic nerve, sympathetic chain, brachiocephalic
vein, subclavian artery, common carotid artery, suprapleural fascia.
Incomplete decompression and inability to instrument the lower most level makes this approach less
preferred among many surgeons