The corticoperiosteal medial femoral supracondylar flap: anatomical study for clinical evaluation in mandibular osteoradionecrosis.

PURPOSE: An ideal way to treat osteoradionecrosis of the jaws is to transfer an osteogenic, appropriately vascularized flap to the affected site. The corticoperiosteal femoral medial supracondylar flap is being used increasingly in the treatment of complex pseudarthrosis of long bones, but is yet to find robust indications for use in the treatment of osteoradionecrosis of the jaw, the reasons being a lack of anatomical data concerning its vascular supply and the local constraints of its routine harvest. This study presents an anatomical study and literature review to explore its potentials in clinical practice. MATERIALS AND METHODS: A total of 25 legs were dissected following vascular injection of colored neopren. The descending genicular artery (DGA) and veins were studied with particular attention paid to anatomical variations found in their branches. Calibers and length of the vessels were recorded. RESULTS: Many anatomical variations of the DGA were found and a classification proposed. The mean caliber of the DGA at the origin was 1.9 mm, and for the vein, 1.8 mm. The mean useful length of the pedicle was 7.9 cm. A case is reported. CONCLUSION: A clear anatomical knowledge (and, therefore, a sound classification system to grade flap harvesting potential) is the key first step prior to extensive clinical use of this flap. Various anatomical patterns of the pedicle are frequently encountered; branches can be elusive when raising the flap. Vascular imaging is therefore a critical step in identifying types and subtypes before surgery.

Scaling laws for branching vessels of human cerebral cortex.

OBJECTIVE: Vascular architecture, particularly of cerebral microvessels, has profound implications for both health and disease in a variety of areas, such as neuroimaging, angiogenesis and development, Alzheimer's disease, and vascular tumors. We analyzed the architecture of tree-like vessels of the human cerebral cortex. METHODS: Digital three-dimensional images of the microvascular network were obtained from thick sections of India ink-injected human brain by confocal laser microscopy covering a large zone of secondary cortex. A novel segmentation method was used to extract the skeleton and measure the diameter at every vertex. RESULTS: In this paper, we focus on the topology of the cortical tree-like vessels. Using stem-crown decomposition, power-scaling laws were shown to govern the relationships between integrated parameters, such as the distal cumulative length, volume, or normalized flow. This led us toward an experimental confirmation of the allometric equation between mass and metabolic rate. Inversely, the power-law model did not match the relationships between local parameters, such as diameter, and integrated ones. As a consequence, Murray's law did not appropriately model the architecture of cerebrovascular bifurcations. CONCLUSIONS: This study provides a unique, large database and mathematical characterization that may prove valuable for modeling the cerebral.

Branching patterns for arterioles and venules of the human cerebral cortex.

Branching patterns of microvascular networks influence vascular resistance and allow control of peripheral flow distribution. The aim of this paper was to analyze these branching patterns in human cerebral cortex. Digital three-dimensional images of the microvascular network were obtained from thick sections of India ink-injected human brain by confocal laser microscopy covering a large zone of secondary cortex. A novel segmentation method was used to extract the skeletons of 228 vascular trees (152 arterioles and 76 venules) and measure the diameter at every vertex. The branching patterns (area ratios and angles of bifurcations) of nearly 10,000 bifurcations of cortical vascular trees were analyzed, establishing their statistical properties and structural variations as a function of the vessel nature (arterioles versus venules), the parent vessel topological order or the bifurcation type. We also describe their connectivity and discuss the relevance of the assumed optimal design of vascular branching to account for the complex nature of microvascular architecture. The functional implications of some of these structural variations are considered. The branching patterns established from a large database of a human organ contributes to a better understanding of the bifurcation design and provides an essential reference both for diagnosis and for a future large reconstruction of cerebral microvascular network.

Morphometry of the human cerebral cortex microcirculation: general characteristics and space-related profiles.

Studies on human brain microcirculation have thus far yielded few quantitative data, preventing the closest possible interpretation of functional imaging methods such as fMRI and PET that necessarily rely on robustly delineated morphology of haemodynamic systems. Inadequate data in this area can lead to severe underestimation of the spatial specificity of the BOLD response. We took thick sections of Indian ink injected human brain and, using confocal laser microscopy and a novel three-dimensional computer-assisted method we extracted and analyzed hundreds of thousands of vascular segments within a large area of cortex. From this database the global densities, the statistical distributions of diameters and lengths were analysed, separating the tree-like and the net-like parts of the microcirculation. Furthermore, our analysis included variations in volume density along the cortical depth and along vectors parallel to the cortical surface. These morphometric parameters are all key requirements for a sound model of cerebral microcirculation.