• 한국전산유체공학회지
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• 제9권4호
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• pp.34-40
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• 2004

It is known that the non-planar model of bypass is more profitable to suppress the development of intimal hyperplasia that tends to occur preferentially in regions of low time averaged shear stress and rapid temporal changes in wall shear stress. In this study it was numerically simulated the blood flow in an coronary artery grafted by artificial bypass to determine the flow characteristic variations due to the anastomosis angle changing. 5 different non-planar anastomosis angle models such as 45°, 60°, 90°, 120° and 135° were considered. When the anastomosis angle is higher, the backward flow region is spatially extended near the downstream region of the anastomosis because of the development of horseshoes vortex. For the case of the nan-planar 45° and 60° of anastomosis, the area of low-OSI zone was decreased by 26% and 13% respectively and the time averaged wall shear stress was increased by more than 55% as compared with 45° of planar model. However, both of the area of the low-OSI zone and the time averaged wall shear stress of 90°, 120° model were significantly increased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.877-882
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• 2001

A finite element analysis of end-to-end artery/PTFE anastomosis has been presented in this study to evaluate the distribution of compliance and stresses in the vicinity of the anastomosis due to any mismatch in compliance characteristics. The artery wall was assumed to be made of linear isotropic material in this simplified model and a nonlinear analysis and convergency study with respect to increasing meshed element numbers were performed with a mean artery pressure loading of the artery-PTFE model. Also, sub-modeling method was introduced to progress the accuracy of the finite element analysis. The results are as follow : 1. A hypercompliant zone on the artery side was observed around 4.0mm from the anastomosis and a high hoop stresses in the wall of artery and PTFE was dominent. 2. An artery displays large deformation so that nonlinear analysis and sub-modeling method was used. 3. An anastomosis with the thinner thickness and larger diameter PTFE (C type) could reduce the compliance disagreement.

• 대한기계학회논문집A
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• 제27권1호
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• pp.34-41
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• 2003

Finite element analysis of end-to-end artery/PTFE anastomosis recently have been researched. But, these studies were carried out without the compensation for the error of finite element analysis and assumed the artery and PTFE as the simple cylindrical shape in spite of being the fatty tissue which covers the heart. Therefore, we performed the convergency study with respect to increasing the element numbers and considered the fatty tissue as the elastic foundation in the finite element analysis. The results are as fallow ： 1. An anastomosis with the thinner thickness and larger diameter PTFE than artery could reduce the compliance disagreement. 2. A fatty tissue was affected to reduce the compliance mismatch in the vicinity of anastomosis of different material. Therefore a hypercompliant zone become narrorw and a compliance discrepancy decrease between the artery and the PTFE about 70%. And radial displacement with respect to longitudinal direction of an artery and the PTFE anastomosis was similar to a sectional compliance.

• Archives of Plastic Surgery
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• 제49권4호
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• pp.549-553
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• 2022

Chylothorax is a rare disease and massive lymph fluid loss can cause life-threatening condition such as severe malnutrition, weight loss, and impaired immune system. If untreated, mortality rate of chylothorax can be up to 50%. This is a case report of a 3-year-old child with iatrogenic chylothorax. Despite conservative treatment and procedures, like perm catheter insertion, the patient failed to improve the respiratory symptoms over 3 months of period. As an alternative to surgical option, such as pleurodesis and thoracic duct ligation which has high complication rate, the patient underwent lymphovenous anastomosis (LVA) and lymph node to vein anastomosis (LNVA). Follow-up at fourth month showed clear lungs without breathing difficulty despite perm catheter removal. This is the first report to show the effectiveness of LVA and LNVA against iatrogenic chylothorax.

• Journal of Gastric Cancer
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• 제20권3호
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• pp.277-289
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• 2020

Purpose: To evaluate the feasibility and safety of intracorporeal overlapping gastrogastrostomy between the proximal anterior wall and antrum posterior wall (PAAP; PAAP anastomosis) of the stomach in minimally invasive pylorus-preserving gastrectomy (PPG) for early gastric cancer (EGC). Materials and Methods: From December 2016 to December 2019, 17 patients underwent minimally invasive PPG with PAAP anastomosis for EGC in the high body and posterior wall of the stomach. Intraoperative gastroscopy was performed with the rotation maneuver during proximal transection. A longer antral cuff (>4-5 cm) was created for PAAP than for conventional PPG (≤3 cm) at the point where a safe distal margin and good vascular perfusion were secured. Because the posterior wall of the proximal remnant stomach was insufficient for intracorporeal anastomosis, the anterior wall was used to create an overlapping anastomosis with the posterior wall of the remnant antrum. The surgical and oncological outcomes were analyzed, and the stomach volume was measured in patients who completed the 6-month follow-up. The results were compared to those after conventional PPG (n=11 each). Results: PAAP anastomosis was successfully performed in 17 patients. The proximal and distal resection margins were 2.4±1.9 cm and 4.0±2.6 cm, respectively. No postoperative complications were observed during the 1-year follow-up esophagogastroduodenoscopy (n=10). The postoperative remnant stomach (n=11) was significantly larger with PAAP than with conventional PPG (225.6±118.3 vs. 99.1±63.2 mL; P=0.001). The stomach length from the anastomosis to the pylorus was 4.9±2.4 cm after PAAP. Conclusions: PAAP anastomosis is a feasible alternative for intracorporeal anastomosis in minimally invasive PPG for highly posteriorly located EGC.

• 대한의용생체공학회:의공학회지
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• 제24권2호
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• pp.113-119
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• 2003

본 연구에서는 end-to-end 문합시 변형된 직경의 불일치로 인하여 발생하게 되는 혈관질환을 방지하기 위하여 기계역학적 거동을 유한요소 법을 이용하여 해석한 결과를 나타내었다. 이 연구에서는 서로 다른 직경을 가지는 동맥과 인공혈관인 PTFE의 문합시 봉합으로 인한 예변형을 고려하였으며, 봉합된 문합부에 수축기혈압인 120mmHg(16.0KPa)을 작용시켜 혈관의 변형을 분석하였다. 변형 후 최종 문합부의 형상은 동맥과 PTFE의 초기 직경비(R$_{I}$)와 PTFE의 두께에 대하여 분석하였다. 그리고 동맥과 PTFE의 초기 직경비가 문합부에서 발생되는 응력에 어떠한 영향을 미치는지에 대하여 해석하여 다음과 같은 결과를 얻었다. 1. 혈관내막의 증식등을 고려하지 않고 봉합으로 인한 예변형과 수축기 혈압만을 고려할 경우 가장 이상적인 초기 직경비(R$_{I}$)는 1.073이다. 2. 상당응력과 원주방향응력은 초기 직경비(R$_{I}$) 증가에 따라 증가하며 모두 접합부에서 PTFE측으로 0.4mm 떨어진 지점에서 최대값이 발생하였다.

• 대한의용생체공학회:의공학회지
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• 제13권4호
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• pp.339-352
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• 1992

A numerical simulation of the steady and pulsatile flow across the end-to-side anastomosis was performed In order to understand the role of flow dynamics in the preferential bevel opment of distal anastomotic intimal hyperplasla. The finite element technique was employed to solve two-dimensional unsteady pulsatile flow in that region. The results of the steady flow revealed that low shear stresses occur at the proximally occluded host artery and at the recirculation region in the Inner wall just distal to the toe region of the anastomosis. The nor- mal;zed wall shear rate was increased, as was the recirculation zone size in the host artery of the by-pass graft anastomosis, with increased anastomotic junction angle. In order to min imize the size of the low wall shear region which might result in the intimal hyperplasia in the by-pass graft anastomosis, a smaller anastomotic junction angle is recommended. The pulsatile flow simulation revealed flow that regions of low and ascillating mali shear do exist near the anastomosis as In the steady simulation. The shift of stagnation point depends on the pulsation of the flow. As the flow was accelerated at systole, the stagnation point moved downstream, disappered at early diastole and reappeared during late diastole. Low shear stress was also found along both walls of the occluded proximal artery. However, the diastolic flow behavior is quite different from the steady results. The vortex near the occluded artery moved downstream and inwardly during late systole, and disappeared during diastole. Recirculations proximal to the toe and heel regions were significant during diastole. Shear stress oscillation was found along the opposite wall. The results of the present study revealed that tow shear occurs at the proximally occluded host artery aud the recirculation region in the inner wall Just dlstal to the toe region of the anastomosis. The present study suggested that the regions of fluctuated wall shear stress wit flow separation is correlated with the preferential developing regions of anastomosis neointial fibrous hyperplasia.

• 대한기관식도과학회지
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• 제5권2호
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• pp.143-152
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• 1999

Background : the technical modality of esophagogastric anastomosis plays an important part in the factors leading to anastomotic leakage and stricture. Objective : The objective of this study was to compare the leakage and stricture rates between the different anastomosis techniques. Materials and Methods : A retrospective study was undertaken in the patients with esophageal cancer who underwent a esophagectomy. Hand-sewn anastomosis was performed in one layer with interrupted sutures(Manual group). The stapler group was divided into two subgroups, such as PCEEA group and Endo-GIA group. Results : The differences of preoperative patient profiles between the groups were not significant. Overall mortality fates were 5% in manual group, 5% in PCEEA group and 11.5% in Endo-GIA group. Fewer anastomotic leakage occurred in manual group(5%) than in PCEEA group(10%) or in Endo-GIA group(15.4%). The postoperative stricture rate was higher in PCEEA group(35%) than in manual group(5%) or in Endo-GIA group(0%) Conclusion : Statistically, there were no significant differences in the anastomotic leakage and stricture rates between the hand-sewn and mechanical anastomosis. But the stricture rate was lower in the group using the linear stapling device and the leakage rate was lower in the hand-sewn group than the other groups.

• Journal of Periodontal and Implant Science
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• 제44권2호
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• pp.50-56
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• 2014

Purpose: The aims of this study were to measure the distance of the intraosseous vascular anastomosis in the anterolateral wall of the maxillary sinus from different reference points, and to correlate the location of the intraosseous vascular anastomosis with the tooth position and the residual bone height of the maxilla. Methods: Computed tomography (CT) images were taken from 283 patients undergoing dental implants placement in the posterior maxilla. Three horizontal lines were drawn at the ridge crest, maxillary sinus floor, and the position of the anastomosis. A vertical second line at the center of each tooth was drawn perpendicular to the horizontal lines. The distance from the ridge crest to the maxillary sinus floor and the distance from the maxillary sinus floor to the bony canal were measured from the intersections of the horizontal and vertical lines. The residual alveolar bone height was used to categorize three groups: group 1,<4 mm; group 2, between 4 and 8 mm; and group 3, >8 mm. Results: The residual bone height values of different tooth positions were significantly different (P=0.0002). The distance from the maxillary sinus floor to the intraosseous vascular anastomosis was significantly different between groups 1 and 3 (P=0.0039). At the molar sites, a moderate negative correlation was found between the residual bone height and the distance from the maxillary sinus floor to the intraosseous anastomosis. The distances of the alveolar ridge crest and the maxillary sinus from the intraosseous vascular anastomosis were not significantly different between sexes. Conclusions: Within the limitations of this study, sites with a higher residual bone height in the molar regions were at a relatively high risk of artery damage during window osteotomy preparation; therefore, we recommend taking more precautions when using a lateral approach for sinus elevation.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5427-5431
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• 2014

Aim: To evaluate the outcome of stapled versus sutured colo-rectal anastomosis after low anterior resection of mid-rectal carcinoma. Patients and Methods: A prospective study of fifty patients who underwent colo-rectal anastomosis following low anterior resection (LAR) of T2 mid-rectal cancers at the Egyptian National Cancer Institute during the time period from June 2010 to June 2013 was conducted. Classification was into two groups; a stapled anastomosis group I (25 patients) and a hand-sewn anastomosis group II (25 patients). All operations are evaluated regarding intra-operative complications such as anastomotic line bleeding, visceral injuries or major blood loss. The anastomotic time and operative time are documented for each operation. All patients are evaluated post-operatively for anastomotic leakage (AL), wound infection and ileus. Results: The distance of the tumor from the anal verge was $9.6{\pm}2.0cm$ in group I and $9.9{pm}2.4cm$ in group II. The mean operative time was $191.5{\pm}16.2min$ in the stapled group and $208{\pm}18.6min$ in the sutured group (p=0.002). The mean anastomotic times were $9.0{\pm}1.9min$ and $19.7{pm}12.2min$ (p=0.001). Anastomotic leakage developed in three (12.0%) patients in the stapled group and in four (16.0%) patients in the sutured group (p=1.000). Post-operative ileus was observed in 3 patients in group I and one patient in group II. Wound infection developed in three (12.0%) patients in the stapled group and four (16.0%) patients in the sutured group (p=1.000). Conclusion: Colo-rectal anastomosis after low anterior resection for mid rectal carcinoma can be conducted safely either by stapling or hand-sewn techniques; however the stapling technique showed shorter anastomotic and operative times with no significant advantages regarding intra- or post-operative complications or hospital stay.