Computational fluid dynamics study of the effect of transverse sinus stenosis on the blood flow pattern in the ipsilateral superior curve of the sigmoid sinus

Author(s):  
Yanjing Han ◽  
Jun Xia ◽  
Long Jin ◽  
Aike Qiao ◽  
Tianhao Su ◽  
...  
2021 ◽  
pp. 159101992110620
Author(s):  
Zhenfeng Li ◽  
Long Jin

Background and Purpose For patients with pulsatile tinnitus who have both transverse sinus stenosis and sigmoid sinus wall anomalies, sigmoid sinus wall reconstruction surgery is the first-choice treatment when the trans-stenotic pressure gradient less than 10 mmHg. However, not all patients are cured by surgery. We hypothesized the abnormal hemodynamics caused by transverse sinus stenosis is associated with the clinical efficacy of surgery. Methods Eight pulsatile tinnitus patients treated with surgery were retrospectively reviewed (4 rehabilitated, 4 nonrehabilitated). All patients had radiologically diagnosed transverse sinus stenosis and sigmoid sinus wall anomalies. A numerical simulation of the hemodynamics of the transverse sinus-sigmoid sinus was performed using computational fluid dynamics technology. Changes in the blood flow patterns before and after surgery were observed. The blood flow velocity at the stenosis, vorticity of blood flow in the sigmoid sinus and wall pressure distribution in the sigmoid sinus wall anomalies area were compared. Results The blood flow velocity in the stenosis (preoperative P = 0.04, postoperative P = 0.004) and vorticity in the sigmoid sinus (preoperative P = 0.02, postoperative P = 0.007) pre- and post-surgery were significantly higher in the non-rehabilitation group than in the rehabilitation group. No significant difference was found in the wall pressure distribution in the sigmoid sinus wall anomalies area (preoperative P = 0.12, postoperative P = 0.24). Conclusions There is a clear correlation between the abnormal hemodynamic status caused by transverse sinus stenosis and the clinical efficacy of surgery. The blood flow velocity at the stenosis and vorticity of blood flow in the sigmoid sinus are factors influencing the clinical efficacy of surgery.


Dynamics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 9-17
Author(s):  
Andrea Natale Impiombato ◽  
Giorgio La Civita ◽  
Francesco Orlandi ◽  
Flavia Schwarz Franceschini Zinani ◽  
Luiz Alberto Oliveira Rocha ◽  
...  

As it is known, the Womersley function models velocity as a function of radius and time. It has been widely used to simulate the pulsatile blood flow through circular ducts. In this context, the present study is focused on the introduction of a simple function as an approximation of the Womersley function in order to evaluate its accuracy. This approximation consists of a simple quadratic function, suitable to be implemented in most commercial and non-commercial computational fluid dynamics codes, without the aid of external mathematical libraries. The Womersley function and the new function have been implemented here as boundary conditions in OpenFOAM ESI software (v.1906). The discrepancy between the obtained results proved to be within 0.7%, which fully validates the calculation approach implemented here. This approach is valid when a simplified analysis of the system is pointed out, in which flow reversals are not contemplated.


2017 ◽  
Vol 16 (1) ◽  
pp. 78-83 ◽  
Author(s):  
Taro Sakashita ◽  
Tamotsu Kamishima ◽  
Hiroyuki Sugimori ◽  
Minghui Tang ◽  
Atsushi Noguchi ◽  
...  

Burns ◽  
2004 ◽  
Vol 30 (4) ◽  
pp. 312-316 ◽  
Author(s):  
P Barachini ◽  
G.M Vezzoni ◽  
C Palombo ◽  
F Franzoni ◽  
G Bigalli

PEDIATRICS ◽  
1987 ◽  
Vol 79 (2) ◽  
pp. 315-315
Author(s):  
KARL C. K. KUBAN ◽  
ELIZABETH BROWN ◽  
ALAN LEVITON ◽  
KALPATHY KRISHNAMOORTHY

In Reply.— We appreciate the comments by Dr Battisti et al. As noted in the inclusion criteria for our study,1 all intubated babies with birth weights less than 1,751 g were eligible for the study. One of the advantages of a randomized double-blind study is that babies with other risk factors, including presence of a fluctuating cerebral blood flow pattern on Doppler ultrasound testing, should have equal chances of being in the treated and placebo groups.


2016 ◽  
Vol 43 (3) ◽  
pp. 154-159
Author(s):  
JAHIR RICHARD DE OLIVEIRA ◽  
MAURÍCIO DE AMORIM AQUINO ◽  
SVETLANA BARROS ◽  
GUILHERME BENJAMIN BRANDÃO PITTA ◽  
ADAMASTOR HUMBERTO PEREIRA

ABSTRACT Objective: to determine the blood flow pattern changes after endovascular treatment of saccular abdominal aortic aneurysm with triple stent. Methods: we conducted a hemodynamic study of seven Landrace and Large White pigs with saccular aneurysms of the infrarenal abdominal aorta artificially produced according to the technique described. The animals were subjected to triple stenting for endovascular aneurysm. We evaluated the pattern of blood flow by duplex scan before and after stent implantation. We used the non-paired Mann-Whitney test for statistical analysis. Results: there was a significant decrease in the average systolic velocity, from 127.4cm/s in the pre-stent period to 69.81cm/s in the post-stent phase. There was also change in the flow pattern from turbulent in the aneurysmal sac to laminate intra-stent. Conclusion: there were changes in the blood flow pattern of saccular abdominal aortic aneurysm after endovascular treatment with triple stent.


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