In order to investigate the influence on the blood flow direction and pattern at the arterial bifurcation, the mesenteric arterioles of 19 SD rats were observed under the OLYMPUS BH2 surgical microscope. After the rats were anesthetized and the body temperature was kept at 37℃ to 38℃, the mesenteric membrane wasexposed and the pattern and direction of the blood flow of the arterioles whichbifurcated at angle of 45±5°, 90±5° and 135±5° were observed. Results showed that the deformation of RBCs made them easy to adapt to the intravascular geometry and pass by fluently without sticking. It was implied that the alteration in arterial flow direction did not cause turbulance at the bifurcation site, and this in return suggested that in end-to-side anastomosis of small arteries,the flow volume would not be reduced and the chance of thrombosis would not be increased.
The human spine injury and various lumbar spine diseases caused by vibration have attracted extensive attention at home and abroad. To explore the biomechanical characteristics of different approaches for lumbar interbody fusion surgery combined with an interspinous internal fixator, device for intervertebral assisted motion (DIAM), finite element models of anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are created by simulating clinical operation based on a three-dimensional finite element model of normal human whole lumbar spine. The fusion level is at L4–L5, and the DIAM is implanted between spinous process of L4 and L5. Transient dynamic analysis is conducted on the ALIF, TLIF and LLIF models, respectively, to compute and compare their stress responses to an axial cyclic load. The results show that compared with those in ALIF and TILF models, contact forces between endplate and cage are higher in LLIF model, where the von-Mises stress in endplate and DIAM is lower. This implies that the LLIF have a better biomechanical performance under vibration. After bony fusion between vertebrae, the endplate and DIAM stresses for all the three surgical models are decreased. It is expected that this study can provide references for selection of surgical approaches in the fusion surgery and vibration protection for the postsurgical lumbar spine.