| Background:Laparoscopic hepatectomy (LH) is widely used in benign lesions and maligmant liver tumors since the advance and improvement of this technique. However, one of limitation is difficult to control the bleeding during parenchymal transection. The bleeding is one of the most important reported reasons to convert from laparoscopic to open surgery. The methods to reduce bleeding include developing laparoscopic instruments and modification of vascular clamping. This technique has been made possible by the liver's known tolerance to normothermic ischemia. Different types of clamping methods have been widely performed in the open surgery, however, this technique has to be performed from the start of LH. The type of controlling hepatic inflow is often applied in LH, but little report relating to the managing of hepatic outflow in LH is available so far. The methods to control hepatic inflow include Pringle maneuver and selective clamping. None was reported about the comparison of Pringle maneuver and selective clamping. The approach to selective clamping include intrahepatic Glissonian approach and dissection of hepatic artery as well portal vein separately. None was reported about the comparison of two different approaches to selective clamping. The controversy is still existing regarding controlling hepatic outflow extraparenchymally before liver transection.Objective:1 To provide applied anatomy of hepatic pedicle for LH and to design safe and convenient operative approach.2 To compare the perioperative and postoperative outcomes of LH with/without intermittent Pringle maneuver.3 To compare the perioperative and postoperative outcomes of LH with selective vascular control and intermittent Pringle maneuver.4 To compare the perioperative and postoperative outcomes of LH with two approaches to selective vascualr clamping.5 To investigate the operative approach to control hepatic outflow extra-parenchymally before transection in LH.Methods:1 Ten antisepsis adult cadaveric liver specimens are studied for the laparoscopic applied anatomy of hepatic pedicle, hepatic artery, portal vein and hepatic vein. The length and angle of these structures are recorded. Additionally,106 videoes of LH are also studied for the characteristics of these structures in laparoscopy.2 Retrospective study compares the perioperative and postoperative outcomes of LH with and without intermittent Pringle maneuver. The outcome parameters include operative time, bleeding, transfusion volume, complications, hospital stay period, liver function tests, routine blood tests, coagulation function tests, postoperative recurrence and survival rate of liver cancer.3 Retrospective study compares the perioperative and postoperative outcomes of LH between with the intermittent Pringle maneuver and with the selective vascular clamping. The outcome items are same as above mention. 4 Retrospective study compares the perioperative and postoperative outcomes of LH in the two approaches to selective vascualr clamping. The outcome parameters are same as above mention.5 The study is to investigate the resutls of controlling hepatic outflow extra-parenchymally in LH. These include operative time, bleeding, transfusion, complications, hospital stay period, postoperative recurrence and survival rate of liver cancer. The study also describes the characteristics of approach for dissecting left and right hepatic vein extraparenchymally.Results:1 The characteristics of hepatic pedicles and length and angle of the structures are described as follows.1.1 The plane of hepatic artery is lower than bile duct in 90% specimens. The place of portal bifurcation is always behind hepatic artery and bile duct.1.2 The left hepatic veins have common trunk with middle hepatic veins in 90% specimens. A gap exists between the right hepatic vein and common trunk of left and middle hepatic vein. The gap is soft connective tissue and communicates with anterior surface of the retrohepatic inferior vena cava (IVC).1.3 The short hepatic veins place in the left and right border of IVC. The quantity of short hepatic veins is variate and the mean value is 7±3.1.4 IVC ligament is a broad membranous connective tissue bridging the left and right side edges of the caval groove in which the IVC was embedded. This membrance is neglectful in the cadaveric liver specimens and obvious in the fresh specimens. Its thickness is variate.1.5 The average length of each anatomic structure is as follows:left hepatic pedicle with the average value being 1.19±0.19cm, right hepatic pedicle 1.09±0.14cm, right anterior hepatic pedicle 0.94±0.19cm, right posterior pedicle 0.96±0.14cm, proper hepatic artery 3.27±0.28cm, left hepatic artery 2.28±0.27 cm, right hepatic artery 2.37±0.22cm, left branch of portal vein 1.25±0.21cm, right branch of portal vein 1.39±0.19cm, right anterior branch of portal vein 0.98±0.11cm, right posterior branch of portal vein 0.89±0.16cm.1.6 The average length of hepatic vein is as follows:right hepatic vein with the average value being 0.70±0.24cm, the common trunk of left and middle hepatic vein 1.50±0.35cm.1.7 The average angle of hepatic vessels are:the average value between left and right hepatic artery is 95.6±5.97 degree, the value between left and right branch of portal vein is 107.9±4.58 degree, the value between hepatic vein and IVC is 56.9±5.04 degree, the value between right hepatic vein and IVC is 53.0±3.20 degree.1.8 In comparison with cadaveric liver specimens, these anatomic structures in the laparoscopy show some special characteristics.2 Relating to the perioperative conditions of LH with or without Pringle maneuver indicated that the intraoperative blood loss and transfusion requirement were significantly less in the Pringle group (p<0.01), serum albumin (Alb) levels are significantly higher in the Pringle group on the first day postoperation (p<0.05). Prothrombin time (PT) is significant shorter in the Pringle group on the first postoperative day (p<0.01).3 To compare the results of LH either the intermittent Pringle maneuver or selective vascular clamping, ALT and AST levels from selective vascular clamping group are significant lower than those of Pringle maneuver group (p< 0.05); prealbumin (PA) level is significant higher in the selective vascular clamping group at first five days postoperation.4 No significant difference existing in the perioperative outcomes of LH shows no significant difference in the two approaches of selective vascualr clamping.5 Dissection of left or right hepatic vein extraparenchymally before transection was successfully finished in 5 cases. The dissection approach of left hepatic vein could follow inward the left edge of IVC.The dissection of right hepatic vein should follow upward the anterior surface of retrohepatic IVC.Conclusion:1 The technique of vascular control performed in LH could be depent on anatomic approach.2 Pringle maneuver is necessary in LH, especially in complicated hepatectomy.3 The technique of selective vascular clamping can protect liver function better than Pringle maneuver. But Pringle maneuver is still necessary in special condition such as repairing portal vein injury in LH.4 The two approaches of selective vascular clamping show no significant difference. The choice is up to the operation and surgeon.5 The left and right hepatic vein can be dissected extraparenchymally before transection. The dissection of right hepatic vein should follow upward the anterior surface of retrohepatic IVC.
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