The human costal cartilage: Anatomical and radiological study of macro-vascularization and micro-vascularization and its clinical relevance regarding vascularized chondrocostal free flap surgery

Introduction: Cartilage repair usually involves in non-vascularized osteochondral or chondral grafts with some drawbacks potentially linked to the lack of vascular supply in those grafts. The aim of this study was to describe a surgical approach for harvesting a vascularized chondrocostal graft, to study the vascular supply to the perichondrium and finally to describe the perichondrium micro-vascularization in order to know how such grafts could be used in cartilage repair surgery.

Materials and methods: We harvested and studied 18 costal cartilages harvested from 12 fresh anatomical subjects. The anatomic pieces were injected with a radio-opaque tracer, analyzed macroscopically, then a plain X-rays and CT scan analysis with three-dimensional rendering was performed in order to evaluate the characteristics of the different patterns of their vascularization.

Results: The surgical approach to harvest a vascularized 5th chondrocostal graft is explained in detail. All of the cartilages were vascularized by the internal thoracic artery and harvested with a pedicle of an average length of 34mm and diameter of 2.14mm. In all specimens, perichondrium vascularization arises from both superior and inferior intercostal branches. Anastomoses between inferior and superior intercostal branches are always found in all specimens at the level of the epichondrium.

Conclusions: The anatomic approach for harvesting a vascularized chondrocostal graft is simple and only slightly differs from the approach described for harvesting a non-vascularized chondrocostal graft. The vascular supply to the perichondrium of such a vascularized chondrocostal graft is sustained by the internal thoracic vessels which have a sufficient diameter and length to allow easy micro-anastomosis. The organization of the micro-vasculature within the perichondrium allows the graft to be tailored to a large cartilage defects and also to small bipolar cartilage defects.