In the 1980s, the water jet (hydrojet) dissectors appeared for liver resection. The technique was first reported to be applied in 45 lobectomies in dogs and in 4 liver resections in humans [23]. The water jet dissector employs a pressurized jet of water to fragment the liver parenchyma tissue and leave the vascular and ductal structures visible and easily controlled during dissection (Fig. 8.2). Rau and colleagues refined this technique in in vitro and in vivo trials and introduced it into clinical routine in liver surgery [24]. Rau et al. found that a pressure of 30–40 bar and a nozzle diameter of 0.1 mm are very effective to dissect normal liver tissue, and the pressure needed for dissection is 10 bar higher in case of cirrhotic liver parenchyma. However, one disadvantage of water jet and CUSA in liver transection is the long transection time because of the need for ligation or clipping of individual vessels. There are also concerns of increased risk of venous air embolism with water jet technique, although this appears to be a clinically rare problem [25, 26]. In the practice, the water jet should be used in the cirrhotic liver with more experienced, a higher jet pressure is needed to cut the fibrotic hepatic parenchyma. The higher pressure leads to more vessel injuries without coagulation function, especially of the hepatic veins, which corresponds to a higher blood loss. Although the new water jet is added with electoral cautery for hemostasis, it does not work simultaneously.

In the 2000s, the RF-assisted device has been used for hepatic parenchyma transection by creating thermal coagulative necrosis along the transection plane, followed by transection of the coagulated liver using a simple scalpel [27, 28]. This method used an RF needle originally designed for ablation of liver tumors, rather than for liver transection [29], and has been reported to be a useful technique for hepatic resection. This early RF-assisted device is monopolar probe. However, this technique was found to be time consuming, produced uncontrolled amount of energy and excessive amount of dead tissue, and also carried the risk of skin burns from the grounding pad [30].

To address these problems, Habib’s group designed and developed a bipolar RF device, the Habib 4X [31]. The probes are introduced into the liver along the transection plane. The generator is programmed to produce thermal coagulation. This allows a small, less than 10 mm, margin of coagulated liver parenchyma to remain behind ensuring sealed vessels and bile ducts. The probes are introduced again adjacent to the last coagulated area, in a serial fashion, until the area to be transected is ablated. The surgeon can either apply energy to the whole resection margin and then cut or apply energy to a partial section and then cut that section and repeat it (Fig. 8.3). RF-assisted liver resection has been shown to be effective in reducing intraoperative blood loss [31–34]. Moreover, RF-assisted liver resection potentially increases the margin of clearance, thus providing an oncological advantage [35]. However, this technique has the limitation of potential damage to the major intrahepatic bile duct or vessels because there is a risk of the needle being inserted into or near a major intrahepatic segmental bile duct or vessel. Thus its application close to the hilum and the inferior vena cava requires experience and dissection of the hepatic hilum and the hepatic veins before applying this device close to these structures. Left lateral lobectomy needs exposure of biliary duct before application of this device. Besides, the amount of tissue necrosis in the remnant liver is substantial, especially when the transection area is large. This is a major concern when patients with cirrhosis and limited liver function reserve require major hepatic resection [35]. In addition, some researchers reported that RF-assisted liver resection caused a higher rate of both bile leak and abdominal abscess formation and needed a longer operation time compared with clamp crush [36].

Harmonic scalpel, firstly introduced in the 1990s, is an ultrasonic surgical device that simultaneously cuts and coagulates. During liver transection, this technology uses ultrasonically activated shears to seal small vessels between the vibrating blades (Fig. 8.4). The blade’s longitudinal vibration can dissect liver parenchyma easily, creating heat and thereby denaturing protein to form coagulum. Vessels up to 2–3 mm in diameter are coagulated on contact with the vibrating blade. The tissue-cutting effect derives from a saw mechanism in the direction of the vibrating blade [37]. Additionally, the temperature of the harmonic scalpel is less than 80 °C when dissecting, far lower than that of the electrome (150 °C) and thus far less damage to the surrounding tissues. Precise dissection around the important tissues could be performed by harmonic scalpel.

But it is reported that harmonic scalpel was associated with a significantly increased rate of postoperative bile leakage, raising the concern that harmonic scalpel may not be effective in sealing bile ducts [38]. This remains to be proven by a randomized trial, which is not available in the literature yet. The instrument may also be limited to dissect the liver parenchyma around the main trunk of hepatic veins, since it is difficult to achieve sufficient control of bleeding from large vessels using the harmonic scalpel alone [39].

Although the benefit of the use of harmonic scalpel in open liver resection remains uncertain, harmonic scalpel with the longer arm is commonly used in laparoscopic liver resection and could achieve excellent results, especially for resection of peripheral lesions. The harmonic scalpel may also be useful in transection of cirrhotic liver, for which the clamp crush and water jet may not be very effective [37].

The LigaSure vessel sealing system (LVSS) was introduced into clinical practice for liver resection in the 2000s and developed for transection and hemostasis, rather than a standard hemostasis technique [40, 41]. Its wide use in hemorrhoidectomies, neck operations, and pulmonary resections has been well reported [42–44]. The device uses compression pressure and powerful bipolar radiofrequency energy; it causes shrinkage of collagen and elastin between opposing walls of small- and medium-sized blood vessels as well as bile vessels. It can seal effectively and create a permanent seal of arteries up to 7 mm and veins up to 12 mm in a wide variety of clinical applications [45]. It is more efficient than ultrasonic shears for hepatic resection in a porcine model [46].

The LVSS can be used alone for liver transection or in combination with clamp crushing to seal vessels [47]. The use of LVSS improves surgical results via reducing blood loss and transfusion and postoperative complications such as bile leakage and intra-abdominal abscess [45, 48–50]. Similar to the harmonic scalpel, LVSS is a useful instrument for liver transection in the setting of laparoscopic resection of peripheral liver lesions. In one study, LVSS is shown to be effective for liver transection in normal or near-normal liver but to fail to achieve hemostasis in three patients with cirrhotic liver [51]. Nevertheless, the usefulness of LVSS has been highlighted.

Vascular stapling devices have been suggested as alternative instruments for parenchymal transection [52, 53]. Stapler hepatectomy in patients with a diseased liver may, moreover, be supported by the ability to perform resections without routine use of inflow occlusion. The technique is simple and easy to learn and master. Advantages of the stapler technique include a fast transection with potentially reduced intraoperative hemorrhage and postoperative bile leakage due to a highly standardized closure of vascular and biliary structures. Another point that must be taken into account is that dividing the portal branches and the hepatic vein using the stapler is already a central part of many hepatic procedures. The use of endoscopic vascular staplers is a feasible, safe, attractive approach for dividing liver parenchyma during routine hepatic surgery. The results are comparable to those obtained using the CUSA without additional cost. However, the use of a stapler for transection of the liver parenchyma may be applicable in minor wedge resection or left lateral segmentectomy when the liver tissue is not too bulky [37].

Liver resection comes along with risks, and the rate of complications remains high. Therefore, the need to reduce such complications has led to the development of various innovative methods of liver resection. During the past decade there has been a significant increase in the number of liver resections and various new device applications [54]. However, sufficient evidence has still not been accumulated to establish the most effective method, and liver surgeons still select the method of liver transection according to their own preferences.

With the arrival of the precise hepatectomy age, the overall complication rate has often been reported to be markedly decreased, but hemorrhage and bile leakage remain major complications after liver parenchyma transection. Hemorrhage is one of the most serious complications, and re-laparotomy is frequently required to control active hemorrhage. Bile leakage and biloma formation present major obstacles for an uneventful recovery after liver resection [63].