Vascular anatomy of L1 vertebral body in Wistar rat-corrosion-fluorescence, diaphanization and histological analysis, comparison to humans, and importance in blood supply-related investigation.

BACKGROUND

The factors influencing bone healing in complete burst fractures-key to deciding between stabilization or vertebral replacement-remain poorly defined. Arterial vascularization and bone nutrition are known to affect healing or progression to necrosis. However, the role of vascular injury in vertebral fractures is not yet conclusively demonstrated and is not currently factored into the decision-making for ad initium vertebral body replacement surgery. This study aims to analyze the vascularization of the L1 vertebral body in Wistar rats and compare it to human anatomy. The goal is to evaluate the suitability of the Wistar rat as a model for studying vertebral blood supply.

METHODS

Forty-three female Wistar rats (3 months old, 250-350 g) were used. After intraventricular injection of acrylic resin, three specimens underwent vascular corrosion-fluorescence. Twenty rats received latex injections and were converted into modified Spalteholz-cleared specimens. The remaining 20 underwent histological analysis of axial slices at upper, intermediate, and lower vertebral body levels. Cell nuclei of vascular endothelium, bone, cartilage, and marrow components were identified and analyzed by quadrant and central/peripheral distribution.

RESULTS

Several vascular structures observed macroscopically matched human anatomy, including: lumbar segmental arteries (100%), horizontal metaphyseal anastomoses (Hma) (56.52%), vertical anastomoses between adjacent vertebrae (34.78%), primary periosteal arteries (Ppa) (60.87%), anterior spinal canal branch (Ascb) of the lumbar artery (69.57%), its ascending and descending branches (52.17%), posterior intervertebral anastomoses (17.39%), posterior nutritive artery origins (47.83%), medial spinal branches (86.96%) and radicular branches (Rbs) (65.22%). Histologically, the vascular density averaged 101.09 endothelial nuclei per mm2. There was a clear predominance of endothelial cells in the anterocentral region. Statistically significant differences were found in cell density and proportion between central (CA) and peripheral (PA) areas (P<0.001), within central versus lateral regions (P<0.001), and between anterior and posterior regions (P=0.03). The distribution of vascular endothelium, bone, cartilage, and bone marrow components is described.

CONCLUSIONS

The vascular architecture of the L1 vertebral body in Wistar rats shows strong similarity to that of humans. These findings support the Wistar rat as a valid model for future studies on vertebral body vascularization and the role of ischemia in fracture healing and related pathologies.