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.