[Can one harvest a long bone stick in the radial forearm flap? Original radioanatomical and NanoSPECT-CT Bioscan...

The composite radial forearm flap is a surgical option in the reconstruction of large traumatic or oncologic orofacial defects. Nevertheless, it has been criticized for its poor bone transport faculties that would make this flap insufficient in large osseous mandibular reconstructions, or for oral prosthetic rehabilitation with dental implants. What is more, the morbidity of the donor site has often been pointed. The aim of this radioanatomic study was to revisit the vascularization of the composite radial forearm flap, focusing on the bone stick.

A radioanatomic study was performed on seven upper limbs taken from fresh cadavers. First, the vessels were washed with a 40°C solution of potassium acetate. Then an intra-arterial injection of a mixture of lead oxide and agar-agar was performed. 3D-CT-scan examinations of the anatomical pieces were performed. In a second step, the flaps were harvested and analyzed with a Microscan examination (NanoSPECT-CT Bioscan(®), voxel 220 microns). Collateral branches of the radial artery to the bone and the skin were counted and classified.

One radial diaphyseal artery was present in all the cases. The nutrient foramen took place at the anteromedial aspect of the diaphysis, between 45 and 65 % of the length of the bone. A dense anastomotic periosteal network was highlightened, supplied by one to four musculoperiosteal branches, and one to six fascio-periosteal arteries arising from the radial artery. A total of mean five osseous branches, and 12 cutaneous branches have been observed.

The results of the present preclinical study suggested that a 16-cm bone stick could be harvested with an optimal vascular safety, without consideration for the morbidity at the donor site. The original approach in this study, relating anatomy to the preclinical imaging, allowed a precise visualization of the microvascularization of the soft and hard tissues. It opened a field of innovative research in plastic and reconstructive surgery.