Figure 5 : The pledgeted anchoringsutures on the innominate artery and proximal aortic arch shown.
Using these anchoring sutures, the Ethibond suspensionsutures are then placed through them. The inset below shows the
compression of the trachea by the innominate artery and presence of the
thymus (yellow structure) acting as a space occupying structure in a
cross-sectional view.
In order to get a good purchase on the artery, horizontal mattress felt
pledgeted sutures with 5-0 Prolene™ sutures (Ethicon, Somerville, NJ)
with either a BV-1 or a RB-2 needle are used on the artery in a partial
thickness manner as the anchoring sutures. Using these felt pledget as
anchors, 4-0 or 3-0 Ethibond® excel (Ethicon, Somerville, NJ)
suspension sutures with a RB-1 needle are passed through
the sternal table to pull the innominate artery anteriorly towards the
posterior aspect of the sternal table. At, times when the sternal table
is particularly thick as in an older child, a French eye needle with a
larger gauge and size is used to facilitate the passage of the suture.
The advantage of the this composite suture technique is
use of a fine sutures such as a 5-0/ 6-0 Prolene suture with a fine
needle supported with pledgets on the arterial structures as an
anchoring sutures and the use of a more robust suture
such as a 3-0/4-0 Ethibond suture with a stronger needle to pass through
the full thickness of the sternal table as a suspension
suture (Figure 5, 6 ). Also, if the suspension sutures were to
break during the securing process, a new suture can be easily replaced.
For a left aortic arch, the left half of the sternal table is chosen and
vice versa. Before tying down the Ethibond sutures on the anterior
aspect of the sternal table, a mediastinal Blake® drain (Ethicon,
Somerville, NJ) is placed to drain the mediastinum. The tip of it is
tucked into the pericardial space to drain it. The drain is exited
retrosternally just below the xiphoid process (Figure 7 ). A set
of about 2 to 3 sternal wires are placed. The sternal tables are
partially bought together except for a 1 cm gap.
With real time flexible bronchoscopic guidance, the Ethibond® excel
sutures are cinched up and tied on the anterior aspect of the sternal
table. Simultaneously, the innominate artery and the aortic arch can be
observed gradually moving up towards the posterior aspect of the sternal
table. The partial gap in the sternum helps with the visualization of
any of the anchoring sutures cutting through the innominate artery or
snapping of the suspension sutures as the sutures are tightened. The
suture on the aortic arch is tightened first followed by the sutures
distal to it as it is the most robust of the sutures. The innominate
artery should rise up and should be well opposed to the posterior
sternal table to optimize the AA. In one case, there was a cut through
of the anchoring suture on the innominate artery requiring a revision.
With all the sutures tightened and tied, the anterior compression on the
trachea should be relieved and generally there is ≤ 20% residual
tracheal stenosis (Figure 6 ). If this result is not achieved,
then alternate factors causing the compression need to be looked for.
This can range from an innominate artery arising further leftward on a
left aortic arch which cannot be sufficiently addressed just by an
aortopexy or an intrinsic tracheal abnormality. In such cases, the
partial sternotomy is converted to a full sternotomy to evaluate the
anatomy further.