Hemodynamics in the Circle of Willis with Internal Carotid Artery Stenosis under Cervical Rotatory Manipulation: A Finite Element Analysis

Abstract

BackgroundThe circle of Willis (CoW) plays an important role in cerebral collateral circulation. The hemodynamics changes in the CoW have usually been associated with the internal carotid artery (ICA) stenosis, but whether rotatory manipulation will affect it remains unknown.Material/MethodsIn this study we attempted to analyze the influence of rotatory manipulation on the hemodynamics in the CoW in models with or without ICA stenosis by means of finite element analysis. For this purpose, the CoW was reasonably simplified and a fluid-solid coupling 3D finite element model was created by using MIMICS10.0 and ANSYS14.5. The healthy (without stenosis) and the diseased (ratios of stenosis include 15%, 30%, 45%, 60%, 70%, 80%, and 90%) situations were simulated. A remote displacement of 60° was applied at a distal ICA (the right ICA was chosen here) to imitate the rotatory manipulation. Blood flow was then monitored at the anterior communicating artery (ACoA) and posterior communicating arteries (PCoA).ResultsBefore the conduction of rotatory manipulation, blood flow changed significantly only when the stenosis ratio was increased to more than 70%, and the situation did not have significant difference after the application of remote displacement except the model with stenosis ration of 90%.ConclusionsThe result suggests that the rotatory manipulation does not have an obvious influence on the blood flow in the CoW when the stenosis of ICA is less than 90%, and this kind of manipulation is suggested to be a safe technique in most of the clinical applications.

Is fetal‑type posterior cerebral artery a risk factor for intracranial aneurysm as analyzed by multislice CT angiography?

“…First, blood flow is increased in the ICA-PComA and the blood pressure is enhanced, leading to increased impact on the vessel wall ( 15 ). Furthermore, the membrane lacks the muscle layer in the blood vessel wall of the arterial bifurcation and the blood vessel wall appears to be thinning ( 16 ).…”

State-of-the-Art Computational Models of Circle of Willis With Physiological Applications: A Review

“…from more than 100 human arterial samples of CoW for FSI modeling [69]. The FSI models could simulate the blood flow in CoW [70] and its fluctuations under cervical rotator manipulation [71]. With in-vivo measurement of blood flow velocity by transcranial Doppler as inlet condition, capillary blood pressure as outlet condition, and age-related elastic modulus of arterial wall, Jahed et al investigated the effects of different hemodynamic and mechanical parameters (wall shear stress, blood pressure, mechanical stress, displacement) on the formation of aneurysms [72].…”

Manual therapy and cervical artery dysfunction: Identification of potential risk factors in clinical encounters

“…[70][71][72] Symons and Herzog 7 report vertebral artery strain during HVLA is less than that found in range of motion testing, and substantially less than the point of mechanical failure of the artery. Similarly, studies investigating occlusion have suggested the head position for a HVLA thrust has little impact on vertebral artery or internal carotid artery flow, [73][74][75][76] and that the duration of arterial occlusion during the application of an HVLA technique (100-150 milliseconds) is insufficient to effect blood flow to the brain. 77,78 A history of cervical spine trauma should also raise the suspicion of potential cervical spine instability and it has been suggested that there may be an association between this and internal carotid artery insufficiency.…”