TA Approach – Figure 3
This requires meticulous preparation with the patient prepped to enable
access via a 10cm horizontal skin incision over the third rib. The
lateral aspect of the pectoralis major and anterior border of the
latissimus dorsi should be exposed. This incision exposes the fascia of
the serratus anterior enabling the dissection to proceed proximally
towards the apex of the axilla. Upward traction on the arm at this stage
enables the scalenus anterior to be identified with the SV and artery
either side. The insertion of the scalenus anterior into the first rib
can then be divided exposing the anterior aspect of the first rib with
the subclavius muscle visible under the head of the clavicle. This also
needs to be divided at its origin from the medial aspect of the first
rib taking care not to damage the SV. Inferiorly, the intercostal
muscles are divided from the lateral aspect of the first rib which
enables the pleura to be dissected free from the inferior aspect of the
rib. The first rib can then be grasped and divided at the costochondral
junction and divided as far posteriorly as necessary to isolate the SV
and divide any extrinsic bands. The critical technical steps for
successful decompression by the TA approach are excision of the
anteriorly placed subclavius muscle and circumferential periadventitial
dissection of the SV.