Couinaud Liver Research Articles

Transarterial Embolization Affects Recovery in Nonoperative Management of Severe Blunt Hepatic Injuries: A Retrospective Study

Introduction: Transarterial embolization (TAE) has been used as an essential technique in the nonoperative management (NOM) of severe blunt hepatic injuries (BHI) but has a possible risk of tissue ischemia and necrosis, which may affect hepatic recovery. The injured liver tissue gets encapsulated and absorbed by intact liver tissue; therefore, the healing process requires the formation of a wall surrounding the injured tissue. In this study, we determined the impact of TAE on the hepatic healing process.Patients and methods: We reviewed hemodynamically stable patients (n=35; males, 23; females, 12; mean age, 32 years), admitted to our hospitals over a 10-year period, who underwent NOM of severe BHI (American Association for the Surgery of Trauma Organ Injury Scale, grades IV and V). Data collected included demographic information, serial CT findings, severity of hepatic injuries showing lacerations (Couinaud's liver segment classification), TAE performed for active hepatic bleeding, and the amount of hemoperitoneum. Extrahepatic factors were evaluated using the Abbreviated Injury Scale for injuries to the head, face, thorax, and extremities. Time taken by injured segments to encapsulate was individually obtained from serial CTs. Cox regression and Kaplan-Meier analyses were used to identify risk factors associated with delayed healing among the hepatic and extrahepatic factors mentioned above.Results: Risk factors were independently and significantly associated with TAE (odds ratio, 2.45; 95% confidence interval, 1.01-5.92; p=0.047). Multivariate analysis indicated that patients who underwent TAE took 2.45-times longer time to attain liver encapsulation than those who did not undergo TAE and that extrahepatic factors did not correlate with the time to encapsulation.Conclusion: TAE for active liver hemorrhage resulted in a delayed recovery from BHI, regardless of extrahepatic factors.

Surgical Implications of Portal Vein Variations and Liver Segmentations: A Recent Update.

The Couinaud's liver segmentation is based on the identification of portal vein bifurcation and origin of hepatic veins. It is widely used clinically, because it is better suited for surgery and is more accurate in localizing and monitoring various intra parenchymal lesions. According to standard anatomy, the portal vein bifurcates into right and left branches; the left vein drains segment II, III and IV and the right vein divides into two secondary branches - the anterior portal vein drains segments V and VIII, and the posterior drains segments VI and VII. The portal vein variants such as portal trifurcation, with division of the main portal vein into the left, right anterior, and posterior branches, and the early origin of the right posterior branch directly from the main portal vein were found to be more frequent and was seen in about 20 - 35% of the population. Accurate knowledge of the portal variants and consequent variations in vascular segments are essential for intervention radiologists and transplant surgeons in the proper diagnosis during radiological investigations and in therapeutic applications such as preparation for biopsy, Portal Vein Embolization (PVE), Transjugular Intrahepatic Porto-Systemic Shunt (TIPS), tumour resection and partial hepatectomy for split or living donor transplantations. The advances in the knowledge will reduce intra and postoperative complications and avoid major catastrophic events. The purpose of the present review is to update the normal and variant portal venous anatomy and their implications in the liver segmentations, complex liver surgeries and various radiological intervention procedures.

Clinical analyses of laparoscopic hepatectomy for liver neoplasms: a report of 21 cases

The clinical data were retrospectively analyzed for 21 cases of liver neoplasms undergoing laparoscopic hepatectomy from December 2007 to October 2012. Among 11 cases of borderline hepatocellular carcinoma (HCC) (1.0-9.0 cm), 6 of them were of micro hepatocellular carcinoma (MHCC) with a diameter ≤2 cm. There were 10 cases of borderline hepatic benign tumor, including liver hemangioma (n=7), hepatic adenoma (n=1), liver lymphoma (n=1) and liver focal necrosis (n=1). According to Couinaud's liver segmentation method, neoplasm was located on segment Ⅲ (n=13), segment Ⅳ (n=6), segment Ⅴ (n=1) and segment Ⅵ (n=1). Laparoscopic hepatectomy was successful in all patients. There was neither conversion into open approach nor postoperative complications of bile leakage, air embolism or perioperative mortality, etc. The mean operative duration was (120 ± 30) minutes, average hemorrhagic volume (165±79) ml and normal diet & ambulation at Day 1-2 post-operation. The average postoperative hospitalization stay was (16±10)days and 1-year survival rate 100%. The parameters of leucocyte, liver enzymes, albumin and bilirubin returned to normal at Week 1 post-operation. Once a reasonable surgical indication is selected, laparoscopic resection is both safe and effective for peripheral micro hepatocellular carcinoma. Key words: Liver neoplasms; Laparoscopy

Limits of Couinaud's liver segment classification: a quantitative computer-based three-dimensional analysis.

Traditionally, liver surgery relies on Couinaud's liver segment classification. As the position and shape of these segments are variable and their borders are hidden within the homogeneous liver mass, the accuracy of segment identification methods needs computer-aided reevaluation. The segmental liver anatomy of 23 patients receiving diagnostic helical CT scans because of suspected intrahepatic lesion was analyzed with the aid of a computer-based operation-planning system. We compared the standard Couinaud classification, which depends particularly on the main stems of portal and hepatic veins, with a method that calculates the segment borders by analyzing the complete portal venous tree. Volume, shape, and position of the liver segments found by each method were compared. With reference to the portal vein-based method, segmental volumes were overestimated by the classic Couinaud method by up to 24% and underestimated to 13%. Volumes of Couinaud segments 4a, 7, and 8 were generally larger compared with those obtained by the portal vein-based method, whereas segments 3 and 6 were smaller. Gross variations were found in segments 5, 7, and 8. When shape and position were considered, poor correlation was found for five segments (median kappa = 0.35-0.45). Only segments 2, 7, and 8 had kappa values clearly above 0.45 in the majority of cases. The plane that divides the two hemilivers along the middle hepatic vein and the border between the left sector (segments 2 and 3) and the medial sector (4a and 4b) were found in both methods with very good conformity (kappa > 0.75). Couinaud's method of dividing the liver into eight autonomous liver segments has to be accepted as a good approximation. Nevertheless, the volume, position, and shape of these segments and their segmental borders show significant variability.

Ramification pattern and topographical relationship between the portal and hepatic veins in the left anatomical lobe of the human liver.

Sixty-one human livers obtained from donated Japanese adult cadavers were dissected to reveal the ramification pattern of the portal and hepatic veins, and their topographical relationship in the left anatomical lobe. The segmental portal vein supplying S2 (P2) tended to form a single stem, whereas that of S3 (P3) was usually double. An intermediate branch between P2 and P3 was observed in 23.0% of livers. In spite of variation between livers, definite P2 and P3 were identified in 47 specimens. One tributary of the left hepatic vein (LHV) was usually present for drainage of S2, and two tributaries were present for S3 (sometimes also for S2 and/or S4). The latter two tributaries of the LHV and the two subsegmental branches of S3 showed three patterns of three-dimensional interdigitations. From these results, the portal vein system did not seem to have a two segmental composition (i.e., S2 and S3) in 23.0% of specimens, whereas the hepatic vein system did not have an intersegmental course in 23.4%. Thus, there were obvious limitations in using each system to determine the liver segment. Taking the overlapping cases into consideration, the left anatomical lobe of 41.0% of specimens did not seem to fit the definition of Couinaud's liver segment. In addition, four patterns of fissure vein (or scissural vein), > 5 mm in diameter at its terminal, were identified: (1) middle hepatic vein type (left median vein, 9.8%); (2) LHV type (left medial vein, 41.0%); (3) true fissure vein (3.3%); and (4) absent cases (45.9%). The former two types also suggested limitations of the hepatic vein system as an indicator of the segmental border.

Sonographic demonstration of Couinaud's liver segments.

The segmental localization of liver tumors is critical to planning appropriate resection. Couinaud's nomenclature is a surgically relevant system of hepatic segmental anatomy, which defines the liver segments by their relationships to vascular structures, hepatic ligaments, and the gallbladder. We demonstrate a way to accurately localize hepatic masses with sonography.