Impact of Ultrasonic Scalpels for Liver Parenchymal Transection on Postoperative Bleeding and Bile Leakage

Discussion

Although liver surgery has become more widespread and new modalities have been added to the surgical instruments that the hepatobiliary surgeon has at his/her disposal, the rates of complications after hepatic resections remain relatively high, with mortality ranging between 0.3% and 9.7% and morbidity ranging between 4.1% and 47.7% in the various studies addressing this issue. The high levels of morbidity and mortality after hepatectomies that have been reported in several studies can be attributed, at least partly, to the advance of surgical techniques and the expansion of criteria for liver resection. Due to them, hepatobiliary surgeons adopt more technically challenging procedures, which are directed towards parenchymal-sparing operations and in many cases are applied to frail patients. Common postoperative complications include fever, subphrenic abscess, pleural effusion, ascites, coagulation disorders, intraperitoneal bleeding, hemobilia, bile leakage, etc. (16, 17). Specifically, for postoperative bleeding and bile leakage, the reported incidence is 4.2%-10% and 4%-17%, respectively (16-19).

Initially, liver parenchymal dissection was performed without sophisticated modalities, mainly using the clamp-crush technique, in which surgical clamps were used to crush liver parenchyma, in order for small blood vessels and bile ducts to become exposed and ligated. However, new techniques for liver parenchymal transection have emerged and are available to the hepatobiliary surgeon, such as ultrasonic aspirator systems (e.g. CUSA), ultrasonic scalpels (e.g. Harmonic, Lotus), vessel-sealing systems (e.g. LigaSure, Enseal), dissection through radiofrequencies (e.g. RFDS), saline-linked radiofrequency sealer (SLRS) (e.g. Salient Dissecting Sealer), hydrojet and vascular staplers (1-9). CUSA (Tyco Healthcare, Mansfield, MA, USA) and SonaStar combine the energy created by ultrasounds with aspiration for the transection of hepatic parenchyma and skeletonization of small blood vessels and bile ducts, which then can be ligated. Ultrasonic scalpels, such as Harmonic and Lotus, use vibrating ultrasonic shears to coagulate and cut tissues. Thus, they seal and divide small blood vessels and transect hepatic parenchyma. Vessel-sealing systems, such as LigaSure (Covidien, Mansfield, MA, USA) and Enseal (Ethicon Inc., Somerville, NJ, USA), occlude blood vessels and divide liver parenchyma by combining pressure with bipolar diathermy. On the other hand, RDFS uses radiofrequencies to thermocoagulate liver parenchyma, which is transected afterwards (2, 4, 7). Another type of surgical instrument is the Salient Dissecting Sealer (Salient Surgical Technologies, Portsmouth, NH, USA), formerly known as TissueLink, with which blunt parenchymal dissection and seal of small vessels are achieved by using radiofrequencies and cool saline as a conductor. Furthermore, dissection with hydrojet is another technique using water jet with high pressure, which breaks apart hepatic parenchyma and skeletonizes small blood vessels and bile ducts (2, 7). Finally, vascular staplers are also used for liver parenchymal transection, along with division of major blood vessels (2, 4, 7-9).

Several studies have been conducted and evaluated the impact of the exact type of liver parenchymal transection method on intraoperative and postoperative outcomes (1, 5, 6, 10-14). However, most studies and meta-analyses have focused on comparing the novel modalities with the old clamp-crush technique mainly and the various categories of new techniques with each other secondarily. As far as postoperative bleeding and bile leakage are concerned, data can be collected by several original studies and meta-analyses (1, 5, 6, 10-14). A meta-analysis conducted by Alexiou et al. found no significant differences between CUSA and RFDS on one hand and the clamp-crush technique on the other hand in regards to postoperative bile leakage. On the contrary, vessel-sealing systems seemed to have lower risk for postoperative cholorrhea when compared with the clamp-crush technique (1). However, in a meta-analysis conducted by Rahbari et al., no actual differences were detected in terms of postoperative bile leakage when the clamp-crush technique was compared with ultrasonic scalpels, vessel-sealing systems, RFDS, saline-linked radiofrequency sealer and hydrojet. The same meta-analysis also showed that the clamp-crush technique has lower transfusion rates than dissection with hydrojet, but no significant differences with ultrasonic scalpels, vessel-sealing systems, RFDS, or saline-linked radiofrequency sealer concerning postoperative bleeding (6). Furthermore, Aoki et al., Bodzin et al. and Appéré et al. reported that there is no actual difference between CUSA and Harmonic ultrasonic scalpel (10, 13, 14). Moreover, Mbah et al. detected no significant difference between Enseal and Harmonic ultrasonic scalpel regarding postoperative hemorrhage or cholorrhea (12). Finally, Richter et al. found no difference in terms of postoperative hemorrhage or cholorrhea when they compared CUSA, hydrojet and SLRS (11).

Our study is the first attempt to compare two different surgical instruments of the same category, namely ultrasonic scalpels, in terms of postoperative bleeding and bile leakage, and to examine their results when they are used alone or in combination with an ultrasonic surgical aspiration system. Our results suggest that Harmonic and Lotus ultrasonic scalpels do not differ in the rates of postoperative bleeding and bile leakage when used either alone or combined with the SonaStar ultrasonic surgical aspiration system. Further studies are needed in order to identify the most suitable surgical instruments and equipment for liver parenchymal transection that result in lower rates of postoperative bleeding and bile leakage.