Subdivision of liver anterior segment into two units according to hepatic venous drainage

BACKGROUND/AIMS: In anatomic liver resection, consideration of the distribution of the hepatic vein is important for maximizing remnant liver function. We have examined the anterior segment of the liver tomographically and subdivided it according to the hepatic venous distribution. METHODOLOGY: Thirty patients in whom liver tumors were diagnosed and who were examined by three-dimensional computed tomography were reviewed. Portal and hepatic venous distributions in the anterior segment were analyzed using the tomograms obtained, and the anterior segment was divided into the ventral and dorsal units. RESULTS: S8d was present in only 23 cases, out of which in 14 cases, drainage veins were present. When P8d was supplied by P8, S8d together with S8a were classified into the ventral unit (8 cases). When P8d was supplied by P8c, S8d and S8b and S8c were in the dorsal unit (4 cases). S5a was in the ventral unit in 26 cases and the dorsal unit in 4 cases. S5b was in the ventral unit in 11 cases and in the dorsal unit in 19 cases. The ventral unit was drained by the middle, and the dorsal by the right, hepatic vein. CONCLUSIONS: Three-dimensional computed tomography made it possible to classify the anterior segment into ventral and dorsal units according to the distribution of the hepatic vein. This new classification makes possible new operative procedures in which resection is limited to one of the units with or without one or more segments, and which result in better remnant liver function.     

Anterior fissure of the right liver — the third door of the liver

Background/Purpose

Although the anterior segment of the liver has been divided into segments 8 and 5, we have, during surgical or interventional procedures, occasionally encountered patients in whom the right anterior portal vein does not bifurcate into the superior and inferior branches. Thus, the in vivo anatomy of the right liver was reevaluated to clarify the segmental anatomy.

Methods

We evaluated the hepatic venous and portal ramification patterns, using three-dimensional images reconstructed from computed tomography. In addition, liver volumetry was performed.

Results

All branches arising from the anterior trunk were divided into two groups: the right ventral portal branches (RVP) and the right dorsal portal branches (RDP), and the anterior fissure vein crossed between the RVP and RDP. The ventral and dorsal regions of the anterior segment were approximately equal from a volumetric point of view.

Conclusions

The anterior segment seems to be divided into the ventral and dorsal segments by the anterior fissure, and we propose a reclassification of the right liver that divides the right liver into three segments. Dissection of the parenchyma along the anterior fissure makes the third door of the liver open, resulting in the exposing of all Glissonian pedicles of the right liver. The introduction of our segmental anatomy and surgical procedure will allow more systematic and limited liver resections.     

Limited resection of the right hemiliver based on reclassification of the right anterior segment of the liver

We proposed that the anterior segment was divided into ventral and dorsal segments, and reclassified the right hemiliver into three segments; ventral, dorsal, and posterior segments. According to our classification we successfully performed limited resection of the right hemiliver.     

Anatomic liver resection of right paramedian sector: ventral and dorsal resection

The purpose of anatomic resection of the liver is to systemically eliminate malignant tumors that spread via the portal vein. Moreover, it results in reducing bleeding and bile leakage from the cut surface of the liver because Glisson's pedicle resection leads to parenchyma transection. Anatomical resection includes hemi‐hepatectomy, sectionectomy, and segmentectomy. Recently, it has been noticed that this concept is not always appropriate for the liver resection including the right paramedian sector. It can be divided vertically into the ventral and the dorsal area according to the ramification of the third order of the portal veins. In the present study, we focused on the right paramedian sector and described techniques of surgical procedures of hepatectomy including resection of the ventral or dorsal areas.     

A proposed new pancreatic classification system according to segments: Operative procedure for a medial pancreatic segmentectomy

Based on anatomical considerations and our experience in performing segmental resections of the pancreas, we propose here a new pancreatic classification system that divides the pancreas into four segments: posterior, proximal, medial, and distal. We also describe the operative procedures for medial pancreatic segmentectomy, carried out in two patients. Under this new classification system, based on the clinical position of these pancreatic segments, the embryologically termed ventral pancreas is now retermed the posterior segment, while the dorsal pancreas is divided into three segments, termed: the proximal segment (the duodenum-sided segment of the dorsal pancreas that connects with the posterior pancreas), the medial segment (the segment that corresponds with the pancreatic neck), and the distal segment (the area from the left border of the superior mesenteric artery to the hilum of the spleen). Although this division of the pancreas into four segments is a new concept, the development of new and better operative procedures that enable the resection of each pancreatic segment independently has made this concept not only valuable but clinically practical.     

Venous-drainage-guided selective hepatectomy: a novel approach to liver surgery

Selective hepatectomy under the guidance of hepatic venous drainage has not yet been developed because hepatic venous occlusion alone produces no visible congested area. Now that this area can be identified by simultaneous occlusion of the hepatic vein and artery, venous-drainage-guided selective hepatectomy is considered feasible. Because the congested area becomes dysfunctional or atrophic due to the absence of portal blood supply, it can be regarded as a first candidate for preventive resection in livers that may bear latent tumors. We report here a novel approach to selective hepatectomy. Segment 4 hepatectomy and ventral hemisectorectomy of segments 5+8, with middle hepatic vein resection, was undertaken in a patient with hepatocellular carcinoma. After hepatic dissection between segments 2+3 and 4, the root of the middle hepatic vein was isolated. Test clamping of the middle hepatic vein and proper hepatic artery demonstrated a discolored area. Hepatic dissection was performed along the discolored border towards the hepatic hilum, exposing the right anterior portal pedicle with division of the ventral branches. The middle hepatic vein was finally divided. Selective hepatectomy was successfully performed without transfusion or complications. Venous-drainage-guided selective hepatectomy is feasible with acceptable perioperative results.     

Surgical anatomy of the medial segment (S4) of the liver with special reference to bile ducts and vessels

BACKGROUND/AIMS: Resection of the inferior area of the medial segment (S4a) plus S5 with preservation of the superior area of the medial segment (S4b) is being performed to manage hilar bile duct carcinoma and pT2 type gallbladder carcinoma, and thus, attention has been focused on the surgical anatomy of the medial segment of the liver to identify the specific vessels and bile ducts of the areas of that segment to be resected and to be preserved. METHODOLOGY: Anatomical study of the bile duct, portal vein, middle hepatic vein, and middle hepatic artery to the medial segment branches of the liver (S4) was performed in a total of 171 specimens comprised of 71 adult cadavers, and 100 liver casts. RESULTS: 1) Two main types of bile duct branches of the medial segment (B4) were recognized. Type I included the branches which joined to the left hepatic duct on the hilar duct side (35.5%), and type II included the branches that joined on the peripheral side (54.6%). Several subtypes were also found in both types. The B2-B3 confluence was mostly on the left (41.7%) or posterior (42.7%) to the umbilical portion (UP) of the portal vein, and to the right of the UP (hilar side) in only 15.6%. 2) The portal vein of the medial segment branches (P4): P4a branched from the right angle and upper right border of the UP in every specimen. The most common morphology was 1 large and 2-3 small branches (41%). P4b was almost always found to branch posterior to the UP and lower than P4a, and the most common morphology was 1 large and 0-1 small branches (57.8%). 3) The middle hepatic vein: In 83.2% a common trunk was observed at the confluence with the inferior vena cava, and 8 types of the middle hepatic vein were recognized. 4) The middle hepatic artery: It arose from the left hepatic artery in 61.5%, from of the right hepatic artery in 27.5%, from the proper hepatic artery in 5.5%, and from both the left and the right hepatic artery in 5.5%. CONCLUSIONS: The detailed vascular and bile duct anatomy of S4 is described. This study should be helpful in identifying the specific vessels and bile ducts of the areas of the medial segment to be resected and to be preserved, thereby facilitating resection of the medial segment.     

肝细胞癌伴门静脉癌栓的降期治疗

肝细胞癌伴门静脉癌栓发生率高,病情进展快,现有治疗方法有限且效果不佳。虽然国外指南推荐索拉非尼为唯一治疗手段,但临床研究显示部分患者,尤其是伴癌栓侵犯至门静脉一级或二级分支的患者(程氏分型Ⅰ/Ⅱ型),通过手术切除可以取得比其他非手术疗法更好的效果。然而临床实践中相当一部分患者由于病灶范围较广无法根治性切除,或者由于癌栓侵犯到门静脉主干(程氏Ⅲ型),术后癌栓残留可能性高,需要通过降期切除的方法改善预后。研究发现通过新辅助三维适形放疗、经肝动脉钇-90微球放射性栓塞、肝动脉灌注化疗等姑息性治疗方法,部分患者(5.7%~26.5%)可出现门静脉癌栓消退乃至消失、肿瘤体积缩小、卫星灶消失等现象,从而使病灶降期,提高手术切除率并延长患者生存时间。多学科综合治疗对于进一步提高肝细胞癌伴门静脉癌栓患者的降期切除率至关重要。     

Anatomic resection of segments 5, 6 and 7 of liver for hepatocellular carcinoma: prior control of right paramedian Glisson

Anatomic resection is theoretically effective in eradicating intrahepatic metastasis of hepatocellular carcinoma (HCC). In patients who undergo a larger volume of hepatectomy or who have hepatic dysfunction, the extent of hepatectomy is limited to avoid postoperative hepatic failure. In the present case, a limited anatomic resection according to Couinaud's segment was performed because of the large volume of the right hemi-liver. A 62-year-old male was found to have a 12-cm HCC in segments 5, 6 and 7, with alcoholic liver disease. The total liver function was Child-Pugh grade A, as indocyanine green retention rate at 15 minutes (ICGR15) was 12%. The resected liver volume of right hemihepatectomy estimated by CT volumetry was 72% and the permitted resected volume based on Takasaki's formula applying ICGR15 was 65%. As the portal branches of segment 8 was free from HCC involvement and the estimated volume of segments 5, 6 and 7 was 51%, we scheduled anatomic resection of these segments to secure remnant liver function. Under Pringle's maneuver, hepatic transection on the border between right and left liver was performed and the right paramedian Glisson's pedicle was exposed in the first step. Branches of segment 5 were divided and the border between segments 5 and 8 was confirmed. Then, the right lateral sector was resected and the right hepatic vein draining segment 8 was secured. Postoperative course was satisfactory and the patient was free from tumor relapse for 16 months after hepatectomy. Under a balance between tumor location and hepatic functional reserve, anatomic resection would be necessary for the treatment of HCC patients.     

Segmentectomy of the liver

Segmentectomy is anatomical resection of segments based on the classification of Couinaud. This procedure is performed mainly for hepatocellular carcinoma. Invasion of portal vein and intrahepatic metastases often occur with hepatocellular carcinoma. Thus, it is desirable to perform anatomical resection of the cancer-bearing areas for curative purpose. However, segmentectomy is selected when extensive resection must be avoided to preserve liver function. There are major differences between segmentectomy of the left hemiliver (Sg 2-4) and right hemiliver (Sg 5-8). In the former, the branches (third-order branches) arising from the umbilical portion of the portal vein can be ligated prior to liver resection. In the latter, manipulation is difficult. Therefore, ultrasonically guided segmental staining is performed by puncturing the portal branch and injecting a dye. This report described techniques for segmentectomy.     

Combined resection of the portal vein for pancreatic cancer: preoperative diagnosis of invasion by portography and prognosis

BACKGROUND/AIMS: Pancreatic cancer often invades the portal vein because of the anatomical position. Pancreatic cancer with portal vein invasion was not considered operable, and thus the resectability rate was low. METHODOLOGY: Between March 1976 and February 1994, 140 of 243 patients underwent resection, a resectability rate of 58%. A total of 81 (58%) of these patients underwent portal vein resection. We assessed 56 patients in whom the depth of invasion had already been determined histopathologically and whose superior mesenteric arterial portograms were readable. The 56 patients were classified into 4 groups: normal (Type I), stricture on one side of the portal vein (Type II), stricture on both sides of the portal vein (Type III), complete obstruction (Type IV). The length of the longitudinal lesions on portograms was also measured. RESULTS: In 93% (27/29 cases) of portographic Type I or II lesions with longitudinal lesions of 2 cm or less, portal vein invasion was limited to the tunica media. No patients with cancer invasion into the lumen survived more than 1 year. CONCLUSIONS: For patients with pancreatic cancer Type I or II, preoperative portography findings and longitudinal lesions of 2 cm or less, portal vein resection is indicated, and long-term survival can be expected.     

Glissonean pedicle transection method for hepatic resection: A new concept of liver segmentation

A new concept of hepatic segmentation along with the Glissonean pedicle tree, and the basis of hepatic resection by the Glissonean pedicle transection method are presented. The portal triad continues from the hepato-duodenal ligament to the intra-hepatic portion as the Glissonean pedicle. That is, the artery, portal vein and bile duct, together with connective tissue, are sheathed by the peritoneum to form a fibroid bundle. The entire length of the primary branches of the Glissonean pedicle and the origin of the secondary branches are located outside the liver and the trunks of the secondary and more peripheral branches run inside the liver. The ramification pattern of the tertiary branches which branch out from each secondary branch is different from patient to patient. The liver is nourished by the secondary branches of the Glissonean pedicle. Each secondary branch feeds one segment. The liver can thus be separated into three segments and an additional caudate area. The area fed by each one of the tertiary branches is cone-shaped; fermed a “cone unit”. Each segment conists of six to eight cone units. In limited resections, the number of cone units to be respected is adjusted and the tertiary branches which feed these areas must be transected selectively through a hilar or a parenchymal approach. To date we have experienced no complications with this procedure, employed for 832 patients with hepatocellular carcinoma.     

Anomaly of the portal vein with an anomalous hepatic vein--the first case report

An anomaly of the portal vein associated with an anomalous hepatic vein is described as the first reported case. A 44-year-old woman was incidentally found to have a huge hemangioma by ultrasonography. Computed tomography revealed an anomalous portal system with a normally located gallbladder and round ligament. Arterial portography revealed anomalous branching of the portal vein, with absence of the left umbilical portion, the curved right portal branch mimicked the right-sided umbilical portion. Hepatic venography demonstrated patent umbilical veins communicating with the left hepatic vein. Intraoperatively the hepatic vein branch was found on the surface of the right hepatic lobe and the common bile duct was dorsal to the hepatic artery. A limited excision of the involved liver was performed safely with the help of the preoperative definition of the abnormal liver anatomy.     

Clinical significance of combined pancreas and portal vein resection in surgery for pancreatic adenocarcinoma

BACKGROUND/AIMS: Surgical resection remains the only potentially curative treatment for pancreatic adenocarcinoma for which the resectability and prognosis are still poor. The aim of the present study was to evaluate the efficacy of portal vein resection for pancreatic adenocarcinoma. METHODOLOGY: Between August 1983 and December 2000, 69 patients with pancreatic ductal cell carcinoma underwent resection in our department; 22 of the 69 had combined resection of the pancreas and portal vein. When the pancreas could not be separated from the portal vein, the vein was judged to be invaded by cancer and resected. RESULTS: The mortality rate for portal vein resection was 4.5%, which was similar to that in 47 patients with no resection of the portal vein (2.1%). Postoperative histologic analysis showed that 8 (37%) of the patients who underwent portal vein resection did not have cancer invasion to the portal vein, and 3 of them remain disease free to date. The 3-year survival rate of patients undergoing portal vein resection was 21.3%, and that of patients without portal vein resection was 20.0%. CONCLUSIONS: Resection of the portal vein in cases of pancreatic ductal cell carcinoma has no adverse affect on long-term survival for selected patients.     

Head dorsal pancreatectomy: An alternative to the pancreaticoduodenectomy for not enucleable benign or low-grade malignant lesions

BackgroundHead dorsal pancreatectomy (HDP) is a segmental pancreatic resection, conservative variant of total dorsal pancreatectomy, applied to preserve the functional pancreatic parenchyma as an alternative to pancreaticoduodenectomy in not enucleable benign or low-grade malignant lesions. The absences of biliary and gastrointestinal resection/reconstruction are the other advantages of the technique.MethodsWe reported a case of HDP performed in a female 39-year-old patient for a neuroendocrine tumour of the dorsal portion of the pancreatic head.ResultsThe superior mesenteric vein was dissected from the pancreatic neck. The pancreas was transected at the left margin of the superior mesenteric vein. After identification and mobilisation of gastroduodenal artery and the anterior superior pancreatico-duodenal artery, the head dorsal segment was dissected stepwise from the duodenal wall toward the common bile duct plane; the dissection of the pancreatic parenchyma was completed along the anterior surface of the common bile duct. An end-to-side duct-to-mucosa pancreaticojejunostomy was performed. The main pancreatic duct in the ventral segment on the dissection parenchymal surface was ligated. With the inclusion of this case, there are a total of 3 cases involving resection of the dorsal portion of the pancreatic head reported in the literature.ConclusionHDP seems to be technically feasible and safe for not enucleable benign or low-grade malignant neoplasms involving the dorsal pancreatic head. However, due to the singularity of the indications and the few cases reported in the literature, further studies are needed to validate the technique.     

Aggressive behaviour of solid-pseudopapillary tumor of the pancreas in adults：A case report and review of the literature

Solid-pseudopapillary tumor （SPT） is a rare neoplasm of the pancreas that usually occurs in young females. It is generally considered a low-grade malignant tumor that can remain asymptomatic for several years. The occurrence of infiltrating varieties of SPT is around 10%-15%. Between 1986 and 2006, 282 cystic tumors of the pancreas were observed. Among them a SPT was diagnosed in 8 patients （2.8%） with only one infiltrating variety. This was diagnosed in a 49-year-old female 13 years after the sonographic evidence of a small pancreatic cystic lesion interpreted as a pseudocyst. The tumor invaded a long segment of the portal- mesenteric vein confluence, and was removed with a total pancreatectomy, resection of the portal vein and reconstruction with the internal jugular vein. Histological examination confirmed the R-0 resection of the primary SPT, although a vascular invasion was demonstrated. The postoperative course was uneventful, but 32 mo after surgery the patient experienced diffuse liver metastases. Chemotherapy with different drugs was started. The patient is alive and symptom-free, with stable disease, 75 mo after surgery. Twenty-five patients with invasion of the portal vein and/or of mesenteric vessels were retrieved from the literature, 16 recent patients with tumor relapse after potentially curative resection were also retrieved. The best treatment remains a radical resection whenever possible, even in locally advanced or metastatic disease. The role of chemotherapy, and/or radiotherapy, is still to be defined.     

Systematic laparoscopic left lateral segmentectomy of the liver for hepatocellular carcinoma

A systematic technique for the resection of hepatocellular carcinoma (HCC) prevents the dissemination of cancer cells through the portal vein of the remnant liver. We successfully performed a systematic laparoscopic left lateral segmentectomy in a 62-year-old man with HCC. The tumor was located in the left lateral segment of the liver, and measured approximately 4 cm in diameter. Since no other tumors were detected in the liver or in any distant organs, the patient was considered to be a candidate for surgery. A laparoscopic hepatic resection was selected as the procedure of choice. Prior to dissection of the liver parenchyma, the arteries and branches of the portal vein feeding the left lateral segment were divided and dissected, together with the branches of the biliary tree in the umbilical portion of the left pedicle of Glisson's capsule. The liver parenchyma was then dissected and the left hepatic vein divided and dissected, and transection of the left lateral segment was completed. The patient's postoperative course was uneventful and he was discharged on postoperative days 14. No evidence of recurrence has been noted in the 22 months after surgery (the time of this report). This less invasive surgery, taking into consideration the pathogenesis of HCC, may be a useful new approach in selected patients with this tumor.     

Intraoperative diagnosis of pancreatic cancer extension using IVUS

BACKGROUND/AIMS: Pancreatic cancer easily invades retroperitoneal tissue, especially the portal vein and extrapancreatic nerve plexus. We evaluated the diagnostic accuracy of intraportal endovascular ultrasonography in portal vein and extrapancreatic nerve plexus invasion. METHODOLOGY: Intraportal endovascular ultrasonography was performed in 78 cases of pancreatic cancer (head 67, body 8, total 3). Intraportal endovascular ultrasonography was performed intraoperatively from the superior mesenteric vein with an 8-French, 20-MHz intravascular ultrasound catheter. Three-dimensional intraportal endovascular ultrasonography was constructed by volume rendering. RESULTS: Intraportal endovascular ultrasonography visualized the portal vein as an echogenic band with a thickness of 0.5 mm to 1.0 mm. The diagnostic criterion of portal vein invasion was obliteration of this echogenic band. Intraportal endovascular ultrasonography visualized segment II of the extrapancreatic nerve plexus as the high-echoic area around the inferior pancreaticoduodenal artery. The diagnostic criterion of extrapancreatic nerve plexus invasion was low-echoic infiltration around the inferior pancreaticoduodenal artery. The sensitivity, specificity, and overall accuracy of intraportal endovascular ultrasonography for diagnosis of portal vein invasion was, respectively, 97.4%, 92.5%, and 94.9%. The values for diagnosis of extrapancreatic nerve plexus invasion, respectively, were 94.4%, 97.1%, and 96.2%. Three-dimensional intraportal endovascular ultrasonography depicted the invasion area as a defect of the portal vein wall. CONCLUSIONS: Intraportal endovascular ultrasonography detected subtle portal invasion and provided accurate portal invasion area which was useful for portal vein an reconstruction. Intraportal endovascular ultrasonography could also diagnose the extrapancreatic nerve plexus invasion of segment II.     

Better surgical treatment method for hepatocellular carcinoma with portal vein tumor thrombus

Hepatocellular carcinoma(HCC) with portal vein tumor thrombus(PVTT) is a disease that is not uncommon, but the treatments vary drastically between Eastern and Western countries. In Europe and America, the first line of treatment is systemic therapy such as sorafenib and the surgical treatment is not a recommend option. While an increasing number of studies from China and Japan have suggested that surgical treatment results in better outcomes when compared to transcatheter arterial chemoembolization(TACE), sorafenib, or other nonsurgical treatments, and two classification systems, Japanese Vp classification and Chinese Cheng's classification, were very useful to guide the surgical treatment. We have also found that surgical treatment may be more effective, as we have performed surgical treatment for HCC-PVTT patients over a period of approximately 15 years and achieved good results with the longest surviving time being 13 years and onward. In this study, we review the efficacy and principles of current surgical treatments and introduce our new, more effective surgical technique named "thrombectomy first", which means the tumor thrombus in the main portal vein, the bifurcation or the contralateral portal vein should be removed prior to liver resection. Thus, compression and crushing of PVTT during the operation could be avoided and new intrahepatic metastases caused by tumor thrombus to the remnant liver minimized. The new technique is even beneficial to the prognosis of Cheng's classification Types Ⅲ and Ⅳ PVTT. The vital tips and tricks for the surgical approach are described.