Chun-Yen Yu

New vertebral osteoporotic compression fractures after percutaneous vertebroplasty: retrospective analysis of risk factors.

PURPOSE To investigate risk factors for new vertebral compression fractures (VCFs) after vertebroplasty. MATERIALS AND METHODS The authors analyzed the occurrence of new VCFs in 70 patients who had previously undergone vertebroplasty for the treatment of one VCF. The following covariates were analyzed: age, sex, body weight, height, body mass index (BMI), treated vertebral level, relative distance between treated vertebrae and new VCFs, pre-existing untreated VCFs, gas-containing vertebrae before treatment, and surgical approach. Surgical variables, including cement leakage into the disk, anterior vertebral height restoration, and kyphosis correction of treated vertebrae were also analyzed. A Cox proportional hazards regression analysis was used to determine the relative risk of new adjacent VCFs. The Kaplan-Meier method was used to calculate mean fracture-free rate over time. RESULTS Seventy patients were reviewed, with a mean follow-up of 20.0 months +/- 10.2 (range, 6-48 months). We identified 22 new fractures in 19 of the 70 patients (27%), with 16 adjacent and six nonadjacent VCFs. The mean time to new fracture was 10.6 months +/- 9.5, and there was no significant difference in time to adjacent or nonadjacent VCF. Increased risk of VCF was associated with proximity to the treated vertebra, greater kyphosis correction, and low patient BMI. The 1-year fracture-free rate was 79.5%. CONCLUSIONS New VCFs are common in patients with a low BMI, which suggests osteoporosis as a mechanism of fracture.

Liver graft-to-recipient spleen size ratio as a novel predictor of portal hyperperfusion syndrome in living donor liver transplantation.

Portal hyperperfusion in a small‐size liver graft is one cause of posttransplant graft dysfunction. We retrospectively analyzed the potential risk factors predicting the development of portal hyperperfusion in 43 adult living donor liver transplantation recipients. The following were evaluated: age, body weight, native liver disease, spleen size, graft size, graft‐to‐recipient weight ratio (GRWR), total portal flow, recipient portal venous flow per 100 g graft weight (RPVF), graft‐to‐recipient spleen size ratio (GRSSR) and portosystemic shunting. Spleen size was directly proportional to the total portal flow (p = 0.001) and RPVF (p = 0.014). Graft hyperperfusion (RPVF flow >250 mL/min/100 g graft) was seen in eight recipients. If the GRSSR was <0.6, 5 of 11 cases were found to have graft hyperperfusion (p = 0.017). The presence of portosystemic shunting was significant in decreasing excessive RPVF (p = 0.059). A decrease in portal flow in the hyperperfused grafts was achieved by intraoperative splenic artery ligation or splenectomy. Spleen size is a major factor contributing to portal flow after transplant. The GRSSR is associated with posttransplant graft hyperperfusion at a ratio of <0.6.

Hepatocellular Carcinoma Downstaging in Liver Transplantation

BACKGROUND Hepatocellular carcinoma (HCC) is the leading malignant tumor in Taiwan. The majority of HCC patients are diagnosed in late stages and therefore in eligible for potentially curative treatments. Locoregional therapy has been advocated as an effective treatment for patients with advanced HCCs. PURPOSE The aim of this study was to evaluate the outcomes of HCC downstaged patients after locoregional therapy to allow eligibility for liver transplantation. METHODS AND MATERIALS From January 2004 to June 2010, 161 patients with HCCs underwent liver transplantation including 51 (31.6%) who exceeded the University of California-San Francisco (UCSF) who had undergone successful locoregional therapy to be downstaged within these criteria. Among the downstaged patients, 48 (94.1%) underwent transarterial embolization; 7 (13.8%), percutaneous ethanol injection; 24 (47.1%), radiofrequency ablation; 15 (29.4%), surgical resection, and 34 (66.7%), combined treatment. RESULTS The overall 1- and 5-year survival rates of all HCC patients (n=161) were 93.2% and 80.5%. The overall 1- and 5-year survival rates of downstaged (n=51) versus non-downstaged (n=110) subjects were 94.1% versus 83.7% and 92.7% versus 78.9%, respectively (P=.727). There are 15 (9.2%) HCC recurrences. The overall 1- and 5-year tumor-free rates of all HCC patients were 94.8% and 87.2%. The overall 1- and 5-year tumor-free rates between downstaged versus non-downstaged patients were 93.9% and 90.1% versus 95.2% and 86.0%, respectively (P=.812). CONCLUSION Patients with advanced HCC exceeding the UCSF/Milan criteria can be downstaged to fit the criteria using locoregional therapy. Importantly, successfully downstaged patients who are transplanted show excellent tumor-free and overall survival rates, similar to fit-criteria group.

Adjuvant concurrent chemoradiotherapy with intensity-modulated pelvic radiotherapy after surgery for high-risk, early stage cervical cancer patients.

Purpose:This study was undertaken to assess local control and toxicity with adjuvant intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy (CCRT) for early stage cervical cancer. Patients and Methods:Between June 2004 and February 2007, 54 patients with early stage cervical cancer (stage IB–IIA) with high-risk factors for treatment failure after surgery were treated with adjuvant pelvic IMRT and CCRT. Adjuvant chemotherapy consisted of cisplatin (50 mg/m2) weekly for 4 to 6 courses. All the patients received 50.4 Gy of external beam radiotherapy with IMRT in 28 fractions and 6 Gy of high-dose rate vaginal cuff brachytherapy in 3 insertions. Results:Adjuvant CCRT with IMRT provided good local tumor control in posthysterectomy cervical cancer patients with high-risk pathologic features. The 3-year locoregional control and disease-free survival were 93% and 78%, respectively. Histology and lymph node metastasis were indicators for disease-free survival. Low acute and chronic treatment-related toxicities were noted with IMRT. All the patients completed the radiotherapy treatment without any major toxicity. In terms of chronic toxicity, only 1 patient had grade 3 genitourinary toxicity and none had grade 3 gastrointestinal toxicity. Conclusion:Our results indicate that adjuvant CCRT with IMRT technique for adjuvant treatment of early stage cervical cancer is associated with excellent local control and low toxicity.

Liver graft regeneration in right lobe adult living donor liver transplantation.

Optimal portal flow is one of the essentials in adequate liver function, graft regeneration and outcome of the graft after right lobe adult living donor liver transplantation (ALDLT). The relations among factors that cause sufficient liver graft regeneration are still unclear. The aim of this study is to evaluate the potential predisposing factors that encourage liver graft regeneration after ALDLT. The study population consisted of right lobe ALDLT recipients from Chang Gung Memorial Hospital‐Kaohsiung Medical Center, Taiwan. The records, preoperative images, postoperative Doppler ultrasound evaluation and computed tomography studies performed 6 months after transplant were reviewed. The volume of the graft 6 months after transplant divided by the standard liver volume was calculated as the regeneration ratio. The predisposing risk factors were compiled from statistical analyses and included age, recipient body weight, native liver disease, spleen size before transplant, patency of the hepatic venous graft, graft weight‐to‐recipient weight ratio (GRWR), posttransplant portal flow, vascular and biliary complications and rejection. One hundred forty‐five recipients were enrolled in this study. The liver graft regeneration ratio was 91.2 ± 12.6% (range, 58–151). The size of the spleen (p = 0.00015), total portal flow and GRWR (p = 0.005) were linearly correlated with the regeneration rate. Patency of the hepatic venous tributary reconstructed was positively correlated to graft regeneration and was statistically significant (p = 0.017). Splenic artery ligation was advantageous to promote liver regeneration in specific cases but splenectomy did not show any positive advantage. Spleen size is a major factor contributing to portal flow and may directly trigger regeneration after transplant. Control of sufficient portal flow and adequate hepatic outflow are important factors in graft regeneration.

Portal vein thrombosis in biliary atresia patients after living donor liver transplantation

BACKGROUND Vascular complications are major complications after living donor liver transplantation (LDLT), especially in biliary atresia (BA). Early diagnosis and treatment of portal vein thrombosis (PVT) may ensure optimal graft function and good recipient survival. Our aim was to find any association between pre- and post-transplant anatomic characteristics and hemodynamics, and the occurrence of post-transplant PVT in BA patients undergoing LDLT. METHODS We evaluated the pre- and post-transplant findings in ultrasonography in 105 BA recipients who underwent primary LDLT to determine the possible associated factor(s) and ultrasonographic warning sign(s) that may cause PVT development after LDLT. RESULTS There were 53 male and 52 female recipients. The mean age, height, and weight were 2.8 years, 83.6 cm, and 12.5 kg, respectively. Occlusion of the portal vein (PV) developed in 8 patients. On multivariate analysis, the only independent, pretransplant risk factor predisposing to PV occlusion post-transplant was small main PV size (P = .008). Post-transplant ultrasonographic warning signs included PV flow <10 cm/sec (P = .003), high hepatic artery flow >70 cm/sec (P = .027), and lesser hepatic artery resistance index <0.65 (P = .013). Both slow PV flow <10 cm/sec and lesser hepatic artery resistance index have high sensitivity and specificity in predicting post-LDLT PVT. CONCLUSION Small PV size (<4 mm) and slow portal flow <10 cm/sec combined with lesser hepatic artery resistance index (<0.65) are strong warning signs that may predict the development of post-LDLT PVT in BA patients that require close monitoring.

Doppler Ultrasound Evaluation of Postoperative Portal Vein Stenosis in Adult Living Donor Liver Transplantation

AIM To evaluate the postoperative portal vein stenosis (PVS) and the diagnostic efficiency of Doppler ultrasound (DUS) in adult living donor liver transplantation (ALDLT). MATERIALS AND METHOD From January 2007 to December 2008, 103 ALDLTs were performed and postoperatively followed by routine DUS. The morphologic narrowing at the anastomotic site (AS) of the PVS was analyzed. We calculated the PV stenotic ratio (SR) using the following formula: SR (%)=PRE-AS/PRE (PRE=pre-stenotic caliber). An SR>50% was defined as the critical point for PVS. We also calculated the velocity ratio (VR) between the AS and PRE, and set the significant VR as >3:1. Statistical analyses were carried out to determine clinical significance. RESULTS Using the definition of morphologic PVS by DUS, there were total 20 cases (19.4%) in this series with SR>50%, which included 17 cases with VR>3:1. Eight cases of severe PVS had a stenotic AS>5 mm and subsequently underwent interventional management. Doppler criteria of SR and VR values were elevated up to 75.8% and 7.5:1, respectively, in these treated cases. Two cases of severe PVS subsequently developed PV thrombosis. Intervention by balloon dilation and/or stenting was performed successfully in this PVS case. CONCLUSION DUS is the most convenient and efficient imaging modality to detect and follow postoperative PVS in ALDLT. The Doppler criteria of SR and VR are both sensitive but less specific. Cases of AS<5 mm require interventional management for good long-term graft survival.

Living donor liver transplantation: the Asian perspective.

Preoperative evaluation of donors for living-donor liver transplantation aims to select a suitable donor with optimal graft quality and to ensure donor safety. Hepatic steatosis, a common finding in living liver donors, not only influences the outcome of liver transplantation for the recipient but also affects the recovery of the living donor after partial hepatectomy. Histopathologic analysis is the reference standard to detect and quantify fat in the liver, but it is invasive, and results are vulnerable to sampling error. Imaging can be repeated regularly and allows assessment of the entire liver, thus avoiding sampling error. Selection of appropriate imaging methods demands understanding of their advantages and limitations and the suitable clinical setting. This article describes potential clinical applications for liver fat quantification of imaging methods for fat detection and quantification, with an emphasis on the advantages and limitations of ultrasonography, computed tomography, and magnetic resonance imaging for quantifying liver fat.

Magnetic resonance cholangiography in living donor liver transplantation.

Objective. Exact knowledge of biliary anatomy is essential in living donor liver transplantation. The purpose of this study was to evaluate the accuracy of pretransplant magnetic resonance cholangiography (MRC) in depicting the biliary anatomy in comparison with intraoperative cholangiography (IOC). Materials and Methods. From May 2006 to July 2009, 451 potential living liver donors underwent pretransplant evaluation at the Chang Gung Memorial Hospital–Kaohsiung Medical Center. Two hundred thirty-three donors underwent donor hepatectomy. Of these, only 203 donors with both preoperative MRC and IOC were included in this study. Results. Of the 451 potential donors, 218 (48.3%) were considered unsuitable for liver donation, hence was immediately disqualified after the initial evaluation for various reasons. Six of the 218 unsuitable donors (2.8%) were excluded due to complicated biliary anatomy. The overall accuracy rate of MRC for defining the biliary anatomy was 91.6%, with 84.9% sensitivity, 96% specificity, 88.2% positive predictive value, and 94.7% negative predictive value. There were 14 misidentified cases. The errors in MRC reading was largely attributed to the poor contrast between the biliary ducts and the surrounding tissues and organs. The concurrence between MRC and IOC were commendable (&kgr;=0.9). No significant biliary complications were noted in the mismatch group. Conclusion. MRC is essential for all pretransplantation evaluation with 91.6% accuracy rate.

Interventional Percutaneous Trans-Splenic Approach in the Management of Portal Venous Occlusion After Living Donor Liver Transplantation

A 2-year-old Chinese boy with progressive familial intrahepatic cholestasis type II–related end-stage liver disease underwent living donor liver transplantation (LDLT) using a left lateral segment graft from his mother. Preoperative computed tomography angiography showed that the hepatic artery, inferior vena cava, and portal vein were patent. The left portal vein of the graft was connected to the recipient’s right anterior portal vein. The left hepatic vein of the graft was connected to the recipient’s hepatic veins with triple venoplasty. The left hepatic artery of the graft was connected to the recipient’s right hepatic artery. The left hepatic duct of the graft was connected to the recipient’s common hepatic duct with a microsurgical technique. After the operation, the infant underwent reworking of the hepatic artery anastomosis twice because of early hepatic artery thrombosis. He also underwent revision of the biliary reconstruction to Roux-en-Y hepaticojejunostomy because of biliary anastomotic stricture. At 18 months post-transplant, there was poor visualization of the intrahepatic portal vein, but there was hepatofugal flow inside the left portal vein during Doppler ultrasound follow-up studies. Splenomegaly and minimal ascites were also noted by ultrasound. The computed tomography angiography study showed mild intrahepatic bile duct dilatation, marked splenomegaly, and occlusion of the transverse portion of the portal vein with collateral vessels also noted. The patient was subsequently referred for a possible interventional radiological procedure as initial management for the occluded portal vein. The patient underwent vascular catheter intervention under general anesthesia. The percutaneous transsplenic approach was performed to puncture the splenic vein with a 21-gauge Chiba needle (Cook, Bloomington, IN) under ultrasonographic and fluoroscopic guidance. The needle was changed to a 4-French coaxial dilator and a 7-French sheath (Terumo, Tokyo, Japan) over a 0.035inch angled hydrophilic guide wire (Terumo) after confirmation that the needle was in the splenic vein. Direct main portal venography and the pressure gradient across the stenosis were then obtained. Portography showed total occlusion of the portal vein at its umbilical portion (Fig. 1). The coronary vein was prominent, and gastroesophageal varices were also noted. The extrahepatic portal pressure was 18 mm Hg, and the intrahepatic portal pressure was 18 mm Hg. Hence, there was no pressure gradient across the area of stenosis. A 0.035-inch guide wire and a 4-French J curve catheter (Terumo) were used to traverse the area of portal vein stenosis (Fig. 2). A wall stent (9.0 mm 5.0 cm; Boston Scientific, Natick, MA) was placed to bypass the area of stenosis from the umbilical portion up to the visualized segment 3 portal vein. A second similarly sized wall stent was placed from the mid portion of the native main portal vein to the splenic vein. Balloon angioplasty (6.0-40 mm, 80 cm; Wanda, Bos-