固定式端面弧齿联轴节的加工方法

为了在国产数控螺旋锥齿轮加工机床上实现端面弧齿联轴节的加工,对固定式端面弧齿联轴节的加工方法进行了研究。分析了端面弧齿联轴节的切齿原理和切齿方法,根据固定式端面弧齿联轴节的调整计算卡,建立了刀盘半径、刀齿顶宽、切削刃压力角、刀尖圆角半径的计算方法。基于端面弧齿联轴节的切齿原理以及国产数控螺旋锥齿轮加工机床的结构,建立了弧齿联轴节切齿加工机床调整参数的计算方法,给出了相关的计算公式并开发了端面弧齿联轴节设计、加工参数计算软件。在国产H350G型数控螺旋锥齿轮磨齿机上,基于软件计算得到的机床调整参数进行了实际的磨齿加工,通过实际的接触区检测和几何参数检测,验证了切齿加工参数计算方法的正确性。

A special recurrent pattern in small hepatocellular carcinoma after treatment:Bile duct tumor thrombus formation

AIM:To investigate the clinicopathologic features of bile duct tumor thrombus(BDTT) occurrence after treatment of primary small hepatocellular carcinoma(sHCC) .METHODS:A total of 423 patients with primary sHCC admitted to our hospital underwent surgical resection or local ablation.During follow-up,only six patients were hospitalized due to obstructive jaundice,which occurred 5-76 mo after initial treatment.The clinicopathologic features of these six patients were reviewed.RESULTS:Six patients underwent hepatic resection(n=5) or radio-frequency ablation(n=1) due to primary sHCC.Five cases had an R1 resection margin,and one case had an ablative margin less than 5.0 mm.No vascular infiltration,microsatellites or bile duct/canaliculus affection was noted in the initial resected specimens.During the follow-up,imaging studies revealed a macroscopic BDTT extending to the common bile duct in all six patients.Four patients had a concomitant intrahepatic recurrent tumor.Surgical re-resection of intrahepatic recurrent tumors and removal of BDTTs(n=4) ,BDTT removal through choledochotomy(n= 1) ,and conservative treatment(n=1) was performed.Microscopic portal vein invasion was noted in three of the four resected specimens.All six patients died,with a mean survival of 11 mo after BDTT removal or conservative treatment.CONCLUSION:BDTT occurrence is a rare,special recurrent pattern of primary sHCC.Patients with BDTTs extending to the common bile duct usually have an unfavorable prognosis even following aggressive surgery.Insufficient resection or ablative margins against primary sHCC may be a risk factor for BDTT development.

Portal vein embolization for induction of selective hepatic hypertrophy prior to major hepatectomy: rationale,techniques, outcomes and future directions

The ability to modulate the future liver remnant(FLR) is a key component of modern oncologic hepatobiliary surgery practice and has extended surgical candidacy for patients who may have been previously thought unable to survive liver resection. Multiple techniques have been developed to augment the FLR including portal vein embolization(PVE), associating liver partition and portal vein ligation(ALPPS), and the recently reported transhepatic liver venous deprivation(LVD). PVE is a well-established means to improve the safety of liver resection by redirecting blood flow to the FLR in an effort to selectively hypertrophy and ultimately improve functional reserve of the FLR. This article discusses the current practice of PVE with focus on summarizing the large number of published reports from which outcomes based practices have been developed. Both technical aspects of PVE including volumetry, approaches, and embolization agents; and clinical aspects of PVE including data supporting indications, and its role in conjunction with chemotherapy and transarterial embolization will be highlighted. PVE remains an important aspect of oncologic care; in large part due to the substantial foundation of information available demonstrating its clear clinical benefit for hepatic resection candidates with small anticipated FLRs.

Prealbumin is predictive for postoperative liver insufficiency in patients undergoing liver resection

AIM:To investigate the risk factors for postoperative liver insufficiency in patients with Child-Pugh class A liver function undergoing liver resection.METHODS:A total of 427 consecutive patients undergoing partial hepatectomy from October 2007 to April 2011 at a single center(Department of Hepatic SurgeryⅠ,Eastern Hepatobiliary Surgery Hospital,Shanghai,China) were included in the study.All the patients had preoperative liver function of Child-Pugh class A and were diagnosed as having primary liver cancer by postoperative histopathology.Surgery was performed by the same team and hepatic resection was carried out by a clamp crushing method.A clamp/unclamp time of 15 min/5 min was adopted for hepatic inflow occlusion.Patients' records of demographic variables,intraoperative parameters,pathological findings and laboratory test results were reviewed.Postoperative liver insufficiency and failure were defined as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak,clinically apparent ascites,prolonged coagulopathy requiring frozen fresh plasma,and/or hepatic encephalopathy.The incidence of postoperative liver insufficiency or liver failure was observed and the attributing risk factors were analyzed.A multivariate analysis was conducted to determine the independent predictive factors.RESULTS:Among the 427 patients,there were 362 males and 65 females,with a mean age of 51.1 ± 10.4 years.Most patients(86.4%) had a background of viral hepatitis and 234(54.8%) patients had liver cirrhosis.Indications for partial hepatectomy included hepatocellular carcinoma(391 patients),intrahepatic cholangiocarcinoma(31 patients) and a combination of both(5 patients).Hepatic resections of ≤ 3 and ≥ 4 liver segments were performed in 358(83.8%) and 69(16.2%) patients,respectively.Seventeen(4.0%) patients developed liver insufficiency after hepatectomy,of whom 10 patients manifested as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak,6 patients had clinically apparent ascites and prolonged coagulopathy,1 patient had hepatic encephalopathy and died on day 21 after surgery.On univariate analysis,age ≥ 60 years and prealbumin < 170 mg/dL were found to be significantly correlated with postoperative liver insufficiency(P = 0.045 and P = 0.009,respectively).There was no statistical difference in postoperative liver insufficiency between patients with or without hepatitis,liver cirrhosis and esophagogastric varices.Intraoperative parameters(type of resection,inflow blood occlusion time,blood loss and blood transfusion) and laboratory test results were not associated with postoperative liver insufficiency either.Age ≥ 60 years and prealbumin < 170 mg/dL were selected on multivariate analysis,and only prealbumin < 170 mg/dL remained predictive(hazard ratio,3.192;95%CI:1.185-8.601,P = 0.022).CONCLUSION:Prealbumin serum level is a predictive factor for postoperative liver insufficiency in patients with liver function of Child-Pugh class A undergoing hepatectomy.Since prealbumin is a good marker of nutritional status,the improved nutritional status may decrease the incidence of liver insufficiency.