The anatomy and variations of the internal thoracic (internal mammary) artery and implications in autologous breast reconstruction: clinical anatomical study and literature review

Abstract

The internal thoracic (IT) vessels (otherwise known as the thoracica interna or internal mammary vessels) are widely used as recipient vessels in autologous breast reconstruction. Despite this, normal and pathological variations in IT artery architecture have been described, and these have the potential to complicate dissection and the selection of suitable vessels. A clinical anatomical study of 240 IT arteries (120 patients) and review of the literature was undertaken. Participants comprised 120 female patients undergoing preoperative imaging of the IT artery prior to autologous breast reconstruction, 42 with computed tomographic angiography (CTA) and 78 with ultrasound. There was complete concordance between surgical and radiological findings. An IT artery was present in 100% of cases, with a duplicate IT artery in two cases (1% overall). The position of the IT artery was between two IT veins most frequently (71.5% of cases), and was lateral to the vein(s) least frequently (6%). There were large IT perforators from the first and second intercostal spaces in 87 and 91% of cases, respectively, with the incidence of such perforators reducing in the lower spaces. The literature highlighted a range of cadaveric and clinical cases in which there was absence of a patent IT artery, variant course or size, and variant relationship to the IT vein. A range of congenital, pathological and iatrogenic variants in IT artery anatomy have the potential to limit the use of the IT artery in autologous breast reconstruction. Preoperative imaging with ultrasound or CTA may provide a clear and accurate method of identifying these anatomical variations pre-operatively.