• Journal of Chest Surgery
• /
• 제57권1호
• /
• pp.70-78
• /
• 2024

Background: This study investigated the outcomes of biventricular repair using right ventricle to pulmonary artery (RV-PA) conduit placement in patients aged <1 year. Methods: Patients aged <1 year who underwent biventricular repair using an RV-PA conduit between 2011 and 2020 were included in this study. The outcomes of interest were death from any cause, conduit reintervention, and conduit dysfunction (peak velocity of ≥3.5 m/sec or moderate or severe regurgitation). Results: In total, 141 patients were enrolled. The median age at initial conduit implantation was 6 months. The median conduit diameter z-score was 1.3. The overall 5-year survival rate was 89.6%. In the multivariable analysis, younger age (p=0.006) and longer cardiopulmonary bypass time (p=0.001) were risk factors for overall mortality. During follow-up, 61 patients required conduit reintervention, and conduit dysfunction occurred in 68 patients. The 5-year freedom from conduit reintervention and dysfunction rates were 52.9% and 45.9%, respectively. In the multivariable analysis, a smaller conduit z-score (p<0.001) was a shared risk factor for both conduit reintervention and dysfunction. Analysis of variance demonstrated a nonlinear relationship between the conduit z-score and conduit reintervention or dysfunction. The hazard ratio was lowest in patients with a conduit z-score of 1.3 for reintervention and a conduit z-score of 1.4 for dysfunction. Conclusion: RV-PA conduit placement can be safely performed in infants. A significant number of patients required conduit reintervention and had conduit dysfunction. A slightly oversized conduit with a z-score of 1.3 may reduce the risk of conduit reintervention or dysfunction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제30권1호
• /
• pp.1-16
• /
• 2004

The use of artificial nerve conduit containing viable Schwann cells is one of the most promising strategies to repair the peripheral nerve injury. To fabricate an effective nerve conduit whose microstructure and internal environment are more favorable in the nerve regeneration than existing ones, a new three-dimensional Schwann cell culture technique using $Matrigel^{(R)}$. and dorsal root ganglion (DRG) was developed. Nerve conduit of three-dimensionally arranged Schwann cells was fabricated using direct seeding of freshly harvested DRG into a $Matrigel^{(R)}$ filled silicone tube (I.D. 1.98 mm, 14 mm length) and in vitro rafting culture for 2 weeks. The nerve regeneration efficacy of three-dimensionally cultured Schwann cell conduit (3D conduit group, n=6) was assessed using SD rat sciatic nerve defect of 10 mm, and compared with that of silicone conduit filled with $Matrigel^{(R)}$ and Schwann cells prepared from the conventional plain culture method (2D conduit group, n=6). After 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were examined using image analyzer and electromicroscopic methods. The SFI and ankle stance angle (ASA) in the functional evaluation were $-60.1{\pm}13.9$, $37.9^{\circ}{\pm}5.4^{\circ}$ in 3D conduit group (n=5) and $-87.0{\pm}12.9$, $32.2^{\circ}{\pm}4.8^{\circ}$ in 2D conduit group (n=4), respectively. And the myelinated axon was $44.91%{\pm}0.13%$ in 3D conduit group and $13.05%{\pm}1.95%$ in 2D conduit group to the sham group. In the TEM study, 3D conduit group showed more abundant myelinated nerve fibers with well organized and thickened extracellular collagen than 2D conduit group, and gastrocnemius muscle and biceps femoris tendon in 3D conduit group were less atrophied and showed decreased fibrosis with less fatty infiltration than 2D conduit group. In conclusion, new three-dimensional Schwann cell culture technique was established, and nerve conduit fabricated using this technique showed much improved nerve regeneration capacity than the silicone tube filled with $Matrigel^{(R)}$ and Schwann cells prepared from the conventional plain culture method.

• Journal of Chest Surgery
• /
• 제57권1호
• /
• pp.53-61
• /
• 2024

Background: In the treatment of esophageal cancer, a gastric conduit is typically the first choice. However, when the stomach is not a viable option, the usual alternative is a colon conduit. This study compared the long-term surgical outcomes of gastric and colon conduits over the same interval and aimed to identify factors influencing the prognosis. Methods: A retrospective review was conducted of patients who underwent esophagectomy followed by reconstruction for primary esophageal cancer between January 2006 and December 2020. Results: The study included 1,545 patients, with a gastric conduit used for 1,429 (92.5%) and a colon conduit for 116 (7.5%). Using propensity-matched analysis, 116 patients were selected from each group for comparison. No significant difference was observed in longterm survival between the gastric and colon conduit groups, irrespective of anastomosis level and pathological stage. A higher proportion of patients in the colon conduit group experienced postoperative complications compared to the gastric conduit group (57.8% vs. 25%, p<0.001). Multivariable analysis revealed that age over 65 years, body mass index below 22.0 kg/m², neoadjuvant therapy, postoperative anastomotic leakage, and renal failure were risk factors for overall survival in patients with a colon conduit. Regarding conduit-related complications, cervical nastomosis was the only significant risk factor among those with a colon conduit. Conclusion: Despite the association of colon conduits with high morbidity rates relative to gastric conduits, the long-term outcomes of colon conduits were acceptable. More consideration should be given perioperatively to the use of a colon conduit, particularly in cases involving cervical anastomosis.

• Journal of Chest Surgery
• /
• 제33권10호
• /
• pp.830-833
• /
• 2000

Homograft has been the conduit of choice in various types of congenital malformations which require right ventricular outflow tract reconstruction. However it has been proven to be less than ideal in young age group because of early failure of the conduite due to valve dysfunction and calcification. Furthermore limitation of availability of homograft particularly small sized conduits for neonates and infants is the most serious problem. A 19 month old female patient with pulmonary atresia and ventricular septal defect was operated on with a bovine jugular venous valved conduit as an alternative to the homograft for her right ventricular outflow tract reconstruction. Postoperative hemodynamic performance of the conduit was excellent without pressure gradient or valve regurgitation. With this early result bovine jugular venous valved conduit seems to be another excellent conduit because of good hemodynamics and size availability but long term follow up is necessary.

• Journal of Chest Surgery
• /
• 제24권2호
• /
• pp.143-152
• /
• 1991

From 1983, until June, 1990, 10 patients with various type of truncus arteriosus underwent total surgical correction including Rastelli procedure at Seoul National University Hospital. The age at operation ranged from 1 month to 9 years [mean 2.1 years]. Six patients had truncus type I, 3 patients had truncus type II, and one patients had truncus type IIIc. Right ventricular pulmonary artery continuity was established with a porcine valved conduit in 6 patients, mechanical valved conduit in 1 patient, and bovine pericardial conduit in 3 patients. The postoperative right ventricular /left ventricular pressure ratio ranged from 0.4 to 0.71 [mean 0.51${\pm}$0.14]. The lung histology revealed grade II pulmonary obstructive disease even at 4 month of age. Five patients were dead in hospital [50%], and they were less than 2 year of age. One patient, who had severs congestive heart failure preoperatively, died of low output syndrome and the other died of low output syndrome with postoperative bleeding. There were three death, because of a pulmonary hypertensive crisis that might have been prevented. Two of the five survivors had conduit failure over a mean follow up of 42 months [range 1 to 78 months]. Obstructed conduit was removed and a new conduit constructed using the conduit bed as the posterior wall and the patch of bovine pericardium and Dacron as patch the roof of the conduit. One patient died of acute cardiac failure during the operation. Although results in infants less than 2 years old have not been good, current improvement of intra-and postoperative care suggested that prompt repair is indicated for infants with truncus arteriosus.

• 한국수자원학회논문집
• /
• 제36권5호
• /
• pp.811-821
• /
• 2003

본 연구에서는 수리모형실험을 실시하여 방류관의 흐름특성을 분석 방류관 설계의 적정성을 검토하는데 있다. 수리모형실험 결과 기본계획의 방류관 통수능은 과소설계 되었고, 이를 토대로 설계 변경한 기본설계의 방류관 통수능 설계치는 실험치와 거의 일치하여 적절하게 설계되었음을 알 수 있었다. 또한 방류관 부압발생 여부 및 종단형상의 적정성을 검토한 결과 허용치 이내 값이 발생되어 적절한 것으로 판명되었다. 이러한 과정을 토대로 기본설계의 방류관 규모 및 위치가 적절하였음이 검토되었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제29권3호
• /
• pp.151-156
• /
• 2003

This study was performed to develop a useful nerve conduit which provides favorable environment for Schwann cell viability and proliferation. Milipore membrane of $0.45{\mu}m$ pore size was selected because it permits nutritional inflow from the outside of the conduit and prevents from invading the fibrotic tissue into the conduit. The membrane was rolled and sealed to form a conduit of 2mm diameter and 20mm length. To improve the axonal regeneration and to render better environment for endogenous and exogenous Schwann cell behaviour, the microgeometry and surface of conduit was modified by coating with thin film of calcium phosphate. Cellular viability within the conduit and attachment to its wall were assessed with MTT assay and SEM study. Milipore filter conduit showed significantly higher rate of Schwann cell attachment and viability than the culture dish. However, the reverse was true in case of fibroblast. Coating with thin film of low crystalline calcium phosphate made more favorable environment for both cells with minimal change of pore size. These findings means the porous calcium phosphate coated milipore nerve conduit can provide much favorable environment for endogenous Schwann cell proliferation and exogenous ones, which are filled within the conduit for the more advanced strategy of peripheral nerve regeneration, with potential of reducing fibrotic tissue production.

• 대한토목학회논문집
• /
• 제14권6호
• /
• pp.1465-1474
• /
• 1994

직립벽(直立壁) 전면(前面)에 중복파(重複波)가 작용할 때 직립벽에 설치된 수로(水路)에 발생하는 비정상류(非定常流) 흐름을 Fourier 전개기법의 비선형(非線形) 중복파 이론을 적용하여 해석하였으며 그 결과를 수리실험(水理實驗)을 통하여 검증하였다. 전반적으로 비선형이론은 선형이론(線形理論)과 비교하여 수로(水路)내의 유량변화를 더 잘 예측함을 확인하였다. 투수성(透水性)의 분석결과 수로내 유량변화의 폭은 파고(波高), 주기(週期)가 클수록, 수로연장(水路延長)이 짧을수록 커짐을 확인하였으며 이들간의 상관관계를 명확히 파악하기 위한 무차원(無次元) 관계식을 제시하였다. 수로의 해수교환기능(海水交換機能)과 직접 관련이 있는 일주기당(一週期當) 평균수량(平均水量)은 수로가 수면하(水面下) 바닥 근처에서는 음방향(陰方向)의 값이 나타날 수 있음을 이론과 실험을 통하여 확인하였고, 최대(最大) 수량(水量)은 입구(入口)가 정수면(靜水面)에 위치하는 수로에서 발생함을 보였다. 아울러, 중복파의 주기가 길수록 그리고 수로의 연장이 짧을수록 해수교환 효과면에서 유리함을 확인하였다.

• Journal of Chest Surgery
• /
• 제19권2호
• /
• pp.306-312
• /
• 1986

The development of extracardiac valved conduits for establishment of RV-PA continuity has permitted repair of previously uncorrectable congenital heart anomalies and has facilitated the repair of other complex lesions. But the distressing problem of neointimal peel formation with eventual conduit obstruction in patients with Dacron valved conduits has led to the need for premature replacement in many patients. Therefore in the absence of pulmonary hypertension, hypoplastic pulmonary arteries, significant right ventricular dysfunction or unrepaired tricuspid regurgitation, preference of a valveless conduit to a valved conduit gives excellent results and may diminish the need for late reoperation. In our Hanyang University Hospital, the Rastelli operation was performed for the repair of pulmonary atresia with a valveless Gore-Tex conduit. The patient was operated on with good result. The CVP after operation was 8-13 mmHg at POD #0 and 4-6 mmHg from POD #3-4. Postoperatively the patient was acyanotic and had improved physical capacity compared with his preoperative status.

• 한국초전도ㆍ저온공학회논문지
• /
• 제5권1호
• /
• pp.71-75
• /
• 2003

The conduit fer superconducting cable is welded and plastically deformed during the jacketing process to make the CICC (Cable-in-Conduit-Conductors) fer a fusion magnet. The jacketing process of KSTAR (Korea Superconducting Tokamak Advanced Research) conductors is composed of several sequential steps such as rounding, welding, sizing, and square-rolling. Since the welded zone in Incoloy 908 conduit is brittle and easy to have flaws, there may be a possibility of stress corrosion cracking during the heat treatment of coil when both the induced tensile residual stress and the concentration of oxygen in the furnace are sufficiently high. The steps of the jacketing process were simulated using the finite element method of the commercial ABAQUS code, and the stress distribution in the conduit in each step was calculated, respectively. Furthermore, the variations of residual welding stresses through the steps of the jacketing process were calculated and analyzed to anticipate the possibility of the stress corrosion cracking in the conduit. The concentrated high tensile residual welding stresses along the welding bead decrease by the plastic deformation of the following sizing step. The distribution in residual stresses in the conductor for magnet coil is mainly governed by the last step of square-rolling.