• Title/Summary/Keyword: JCS

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Unconventional shunt surgery for non-cirrhotic portal hypertension in patients not suitable for proximal splenorenal shunt

  • Harilal, S L;Biju Pottakkat;Senthil Gnanasekaran;Kalayarasan Raja
    • Annals of Hepato-Biliary-Pancreatic Surgery
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    • v.27 no.3
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    • pp.264-270
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    • 2023

  • Backgrounds/Aims: Proximal splenorenal shunt (PSRS) is a commonly performed procedure to decompress portal hypertension, in patients with refractory variceal bleed, especially in non-cirrhotic portal hypertension (NCPH). If conventional methods are hindered by any technical or pathological factors, alternative surgical techniques may be required. This study analyzes the effectiveness of various unconventional shunt surgeries performed for NCPH. Methods: A retrospective analysis of NCPH patients who underwent unconventional shunt surgeries during the period July 2011 to June 2022 was conducted. All patients were followed up for a minimum of 12 months with doppler study of the shunt to assess shunt patency, and upper gastrointestinal endoscopy to evaluate the regression of varices. Results: During the study period, 130 patients underwent shunt surgery; among these, 31 underwent unconventional shunts (splenoadrenal shunt [SAS], 12; interposition mesocaval shunt [iMCS], 8; interposition PSRS [iPSRS], 6; jejunal vein-cava shunt [JCS], 3; left gastroepiploic-renal shunt [LGERS], 2). The main indications for unconventional shunts were left renal vein aberration (SAS, 8/12), splenic vein narrowing (iMCS, 5/8), portalhypertensive vascular changes (iPSRS, 6/6), and portomesenteric thrombosis (JCS, 3/3). The median fall in portal pressure was more in SAS (12.1 mm Hg), and operative time more in JCS, 8.4 hours (range, 5-9 hours). During a median follow-up of 36 months (6-54 months), shunt thrombosis had been reported in all cases of LGERS, and less in SAS (3/12). Variceal regression rate was high in SAS, and least in LGERS. Hypersplenism had reversed in all patients, and 6/31 patients had a recurrent bleed. Conclusions: Unconventional shunt surgery is effective in patients unsuited for other shunts, especially PSRS, and it achieves the desired effects in a significant proportion of patients.

  • https://doi.org/10.14701/ahbps.23-002 인용 PDF

A Numerical Study for Stability of Tunnel in Jointed Rock Using Barton-Bandis Model (BB절리모델을 활용한 절리암반속 터널안정성의 수치해석적 연구)

  • Lee, Sung-Ki;Chung, Hyung-Sik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.3 no.3
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    • pp.15-29
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    • 2001

  • For the pertinent use of NMT method, both characteristics of joints (JRC, JCS and ${\phi}_r$) and characteristics of rock mass (Q-Value) must be investigated carefully. The main objective of the study presented is to investigate how sensitive the predicted behaviour of an underground excavation is to various realistic assumptions about some input parameter for the jointed rock mass. Joint pattern in the tunnel is predicted by statistical approach (chi-square test). In this paper, sensitivity studies involving in joint characteristics were carried out. The parametric studies involving change in Barton-Bandis joint model have shown that JCS is relatively insensitive to JRC and ${\phi}_r$. An increase in JRC value may not, according to the Barton-Bandis model, necessarily lead to a decrease in displacement. The importance of dilation in predicting the behaviour of a rock mass around an excavation is emphasized from a comparison of the Barton-Bandis joint behaviour model with the Mohr-Coulomb model. The Barton-Bandis model predicted higher stress, which allow for the build-up of stress caused by dilatant behaviour.

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New Joint Roughness Coefficient and Shear Strength Criterion Based on Experimental Verification of Standard Roughness Profile (표준 거칠기 단면의 실험적 검증에 의한 새로운 거칠기 계수 및 전단강도 기준식)

  • Jang, Hyun-Sic;Sim, Min-Yong;Jang, Bo-An
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.561-577
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    • 2021

  • The ten standard roughness profiles suggested by Barton and Choubey (1977) were extended to make three-dimensional (3D) joint models whose profiles were identical at any cross section. Replicas of joint models were produced using plaster of Paris, and direct shear tests were performed to verify the joint roughness coefficients (JRC) of the standard roughness profiles. Joint shear strengths measured by direct shear tests were compared with those predicted by the shear failure criterion suggested by Barton (1973) based on JRC, joint compressive strength (JCS), and joint basic friction angle (𝜙b). Shear strengths measured from joints of the first and fourth standard roughness profiles were close to predicted values; however, shear strengths measured from the other joint models were lower than predicted, the differences increasing as the roughness of joints increased. Back calculated values for JRC, JCS, and from the results of the direct shear tests show measured shear strengths were lower than predicted shear strengths because of the JRC values. New JRC were back calculated from the measured shear strength and named JRCm. Values of JRCm were lower than the JRC for the standard roughness profiles but show a strong linear relationship to JRC. Corrected JRCm values for the standard roughness profiles are provided and revised relationships between JRCm and JRC, and new shear strength criterion are suggested.

  • https://doi.org/10.9720/kseg.2021.4.561 인용 PDF KSCI HTML