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Orthopaedic Clinic

Cervicothoracic junction exposure
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Relevant anatomy:
 

The cervicothoracic 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.

Behind thymus 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 layer.

 

Positioning:

 

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 

Course.

 

 

Exposure:

 

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.

The thymus 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

 

 

Potentail Complications:

 

 

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

 

 

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