Blood supply of the sternum and its importance in the internal thoracic artery harvesting

Objectives: Internal thoracic artery (ITA) is the bypass graft of choice due to its long term patency rate. However elevated incidence of sternal infections after the pedicled ITA harvesting revived the interest towards the morphology of the sternal blood supply. The aim of this study was to discuss topography of the sternal branches with emphasis on the internal thoracic artery harvesting.

Material and Methods: This study was conducted on 50 fresh specimens of the anterior thorax wall. Radio opaque material was injected and angiograms of the ITA were performed. Subsequently the specimens were preserved and the dry dissections of ITA and their branches were carried out.

Results: Regarding the origin of the sternal branches three variants were identified:

1) sterno-costal branches (n=10) which supplies the sternum and the intercostals space,

2) sternal branches (n=25) which origins directly from the ITA

3) sterno-perforating branches (n=15). The run off of the sternal branches showed arcade pattern of distribution. Furthermore the perforating branches passing thought the intercostals space also form an arcade structure at the insertion of the internal intercostals muscle.

Conclusions: For the sternal-intercostal and sternal-perforating branches to function as collaterals after the TIA harvesting the common origin trunk must remain intact. Based on morphological data we recommend to ligate the common trunk as close as possible to the ITA consequently the collateral blood flow to the sternum remains intact.