Figure 4 : A : The left lobe of the thymus has been
removed, exposing the innominate vein, the innominate artery, the left
carotid artery and the proximal aortic arch covered by the pericardial
investment. B : A full thymectomy is subsequently performed by
removing the right lobe and is a key step as it increases the
antero-superior mediastinal space. A limited superior pericardiotomy is
performed to expose the junction of the innominate artery and the aortic
arch. It is critical to not circumferentially dissect the
innominate artery.
Typically, three sets of anchoring suture are required.
The first set is placed at the junction middle and proximal thirds of
the innominate artery, the second set is placed at the base of the
innominate artery near the aortic arch and the third set is placed 0.5
to 1 cm below this on the anterior surface of the proximal aortic arch.
At times, additional sutures may have to be placed distally and
proximally to aforementioned sutures to optimize the result. This can be
guided by pulling on the anterior surface of the innominate artery and
the arch with real time flexible bronchoscopic exam to assess sites for
suture placement (Figure 5 ).