Since Mouret performed the first laparoscopic cholecystectomy in 1987, laparoscopic techniques have now been widely used in gastrointestinal surgery, obstetrics and gynecology, and urology with excellent results after 20 years of development. Due to the complexity of liver function and anatomy, laparoscopic hepatectomy (LH) has been relatively slow to develop and is still considered to be a difficult procedure. In this paper, we review the domestic and international literature and combine our practical experience with LH to review the following.
1. History of the development of LH
In 1991, Reich, a gynecologist, applied laparoscopic resection of a benign tumor located at the margin of the liver, which kicked off the development of LH. In 1992, Ganger et al. reported the first case of complex LH, in which the authors applied ultrasonic knife, monopolar electrocoagulation and titanium clips to successfully resect a 6-cm focal nodular hyperplastic lesion. 1993, Wayand and Woisetschlager completed In 1995, Ferzli et al. used ultrasound knife and endoscopic vascular closure to remove an adenoma in segment IV, which was 9 cm in size, and in 1996, Azagra et al. performed a left outer lobe (segments II and III) resection in a patient with adenoma, which was the first regular LH in the world. The successful use of LH for donor graft excision for living liver transplantation in children and adults has been reported overseas.
In 1994, the first laparoscopic hepatectomy for hepatocellular carcinoma (lower right lobe of the liver) was also reported in China. Subsequently, different cases of LH were reported one after another, which accumulated some practical experience for the further development of LH in China. In recent years, high difficulty surgeries such as complete laparoscopic skeletal resection of cholangiocarcinoma (left half of the liver), right third hepatectomy, and re-excision of recurrent hepatocellular carcinoma were reported successively, which made a substantial leap in the level of LH in China.
However, by 2001 there were only about 200 cases of LH worldwide. LH is still regarded as a difficult and high-risk complex surgery.
2. Current status of LH
(1) Indications and contraindications.
With the continuous maturation of technology and improvement of instruments, the indications for LH have gradually expanded from the initial small, marginal, benign disease to large, central, malignant disease. Liu Rong et al. proposed the indications and contraindications for LH based on clinical experience and combined with domestic and international literature.
(2)11 Indications for LH.
(1) Patients with lesions located in Couinaud segments II, III, IVa, V, and VI are the best indications for LH, with tumors located within the hemihepatic range, where anatomical resection of the left outer lobe is expected to be the gold standard for laparoscopic liver resection.
②The size of the lesion should not affect the anatomy of the first and second hepatic hilum. The benign lesion should preferably be no more than 15 cm and the malignant tumor no more than 10 cm. A lesion that is too large has little space for operation, affects exposure, and is traumatic and prone to blood leakage.
③The patient’s liver function is required to be above Child grade B, and there are no serious organic lesions in other organs. The remaining liver can meet the physiological needs of the patient.
④ Preferably no history of surgery for hepatobiliary disease.
⑤ Living liver transplantation donor liver excision (including left outer lobe, left hemiport and right hemiport).
(3) 12 Contraindications for LH.
①If the lesion has invaded the inferior vena cava or the root of the hepatic vein, it is a contraindication to LH because of the difficulty of laparoscopic visualization and the difficulty of controlling bleeding.
②When hepatocellular carcinoma is combined with intrahepatic metastasis, portal vein carcinoma embolus, metastasis of hilar lymph nodes or unclear tumor boundary, it is also a contraindication for laparoscopic surgery.
③A history of upper abdominal surgery with severe intra-abdominal adhesions, severe cirrhosis, and portal hypertension are relative contraindications.
④Child C liver function grade, or other important organ insufficiency.
⑤ Excessive liver lesions affecting the exposure and separation of the first and second hepatic hilum.
3. Surgical approach
According to the time and mode of laparoscopic intervention during liver resection, LH can be divided into total laparoscopic hepatectomy (TLH), hand-assisted laparoscopic hepatectomy (HALH) and assisted laparoscopic hepatectomy (HALH). TLH, hand-assisted laparoscopic hepatectomy (HALH), and assisted laparoscopic hepatectomy (ALH).
TLH is what we usually mean by LH, and the operation process from liver exploration, freeing to lesion removal is done under laparoscopy, which is characterized by the smallest incision and trauma, but the most difficult operation, the greatest chance of complications such as bleeding and air embolism, and the longest operation time due to the lack of tactile help from the hand.
HALH is to make an incision in the abdomen according to the need of surgery, and access to the abdomen through a hand-assisted device (hand port).
One hand is used to help the operation, the incision and the degree of trauma are larger than TLH, but due to the introduction of the tactile help of the hand, it can effectively speed up the operation, reduce the difficulty of the operation, and if bleeding occurs, it can be controlled in time, thus avoiding the occurrence of air embolism. If the size of the specimen is exactly equal to the size of the hand-assisted incision, HALH only makes the incision in advance and does not add extra length to the incision. Of course, HALH requires a specific device, and most of the hand-assisted devices currently used in the market are disposable imported products, which are relatively expensive and largely limit the use of HALH.
ALH is performed in two stages, with the former stage being performed under complete laparoscopy for exploration, freeing and separation with low difficulty and risk, and the latter stage making an incision at the appropriate site to perform liver resection in an open state. This technique effectively utilizes the advantages of laparoscopy in terms of magnification and visual field, and greatly reduces the surgical incision. Although it is not as minimally invasive as TLH, the instrumentation requirements are relatively low, and only one set of basic laparoscopic instruments is needed to complete the operation, which is economical and practical and suitable for carrying out in some units with relatively poor economy and equipment.
The above three surgical modalities are not set in stone and can be adjusted according to surgical needs. In addition, HALH and ALH can be used as a practice modality for beginners to gradually transition to TLH.
Surgical instruments
①General instruments
The 30° laparoscope provides a wide field of view and is the basic instrument for LH.
The laparoscopic adjustable ultrasound probe can not only perform intraoperative lesions, anatomical landmarks, and accurate localization of the vasculature to determine the adequate scope of surgical resection, but can also be explored at the end of surgery to prevent missed and important structural damage, and is an essential tool for LH.
In addition, monopolar electrocoagulation, bipolar electrocoagulation, five-lobed pulling hook, non-invasive tissue forceps, transparenchymatous clamping, disposable clamping forceps and titanium clamps, tissue glue, hemostatic gauze and disposable retrieval bags are all necessary instruments to ensure the successful completion of LH.
②Liver separation and dissection instruments
Ultrasonic dissection: The working principle is that the ultrasonic frequency generator makes the metal blade oscillate mechanically at an ultrasonic frequency of 55.5 kHz, which vaporizes the water molecules in the tissue and breaks the tissue, so that the tissue can be cut and dissected precisely, with little damage to the surrounding tissue (about 1 mm), and the blood vessels within 2~3 mm can be safely It is a more common method of liver dissection at home and abroad, and has good cutting effect for cases without cirrhosis.
Microwave tissue coagulators (microwave tissue coagulators): It has been used by scholars at home and abroad and is considered a safe and effective method of liver resection, in which needle-type microwave electrodes are inserted one by one along the predetermined hepatotomy line at intervals of about lOm m, so that the liver tissue to be resected forms a lOm m wide microwave curing zone, and then the liver is broken along this narrow zone, and the intrahepatic ducts are separately clamped or ligated. The advantages of this procedure are less bleeding in the hepatic section, a clear field, and a therapeutic effect on the residual tumor near the cut edge.
Water jet dissector: Water jet dissector is a technique that uses a high pressure jet of water to cut through the nozzle. It breaks up and cuts the tissue by high pressure water, while the tougher structures such as blood vessels, bile ducts and nerves can be preserved intact under the same pressure. Compared with high-frequency electric knife, microwave knife, etc., water jet knife uses the kinetic energy of high-pressure water beam to separate tissues without generating heat, so it does not cause any thermal damage to tissues. The use of water jet knife for liver resection is the earliest field of clinical application, and Rau et al. in laparoscopic hepatectomy showed that the advantage is that only the network of blood vessels and bile ducts, etc., remain between the two severed ends of liver tissue cut by the water jet knife, and the operator can easily handle these ducts, therefore, the blood loss is small; in addition, it is possible to adjust the pressure of the water jet knife according to the texture of the liver
In addition, the pressure of the water jet knife can be adjusted according to the texture of the liver for cutting, but there are difficulties in separating liver tissues for Taiwan and cirrhosis.
TissueLink Floating Ball: It is also called bloodless dissecting knife. Its knife head is in a special blunt garden shape, and water droplets keep dripping out from the knife head when working. Using the energy of high-frequency electric knife, the droplets form liquid electrodes, thus producing excellent separation and coagulation effect. At the same time, the temperature of the head will not exceed 100ºC, so it will not produce crust like ordinary electric knife, but by contracting collagen to achieve the purpose of permanent hemostasis. The advantages are: ① clear surgical field, less bleeding, generally no blood transfusion; ② no crust, smoke and pungent odor, and no risk of postoperative crust rupture, shedding and bleeding, no tissue sealant, replacing a variety of hemostatic techniques; ③ no need to block the hepatic portal, with little impact on liver function; ④ easier to control the operation, easier to locate the tissue, relieving the highly stressful atmosphere in liver resection; ⑤ high-frequency energy does not produce arcing and burn through tissues such as blood vessels, bile ducts, etc.
Ligasure Vessel Sealing System: Ligasure for short, its principle is to use real-time feedback and intelligent technology output of high-frequency electrical energy, combined with vascular clamping force, so that the human tissue collagen and fibrin melting denaturation, vascular wall melting and the formation of a transparent band, resulting in permanent lumen closure, can be used for any diameter up to 7mm veins, arteries or It can be used on any vein, artery or tissue up to 7mm in diameter, and after closure the vessel can withstand three times the systolic pressure of a normal human artery, with the same effect as vascular clamping and suture ligation, with the following advantages: safe and permanent closure of vessels up to 7mm in diameter, direct closure of tissue bundles, no incision or stripping, precise action on tissue vessels, minimal heat diffusion and negative damage, no tissue adhesions and crusts, no foreign bodies in the body, reduced bleeding, and visible lumen closure. It reduces bleeding and creates a visible transparent band after closure. Using this system, the intrahepatic ductal tissue can be safely and rapidly treated with less procedural bleeding, satisfactory results, and a quick recovery process.Ligasure is a relatively ideal method of laparoscopic liver dissection technique compared to ultrasonic knife combined with wire cutters and titanium clips for liver dissection because of its shorter operative time and ease of operation. However, it should be noted that the dilated intrahepatic bile ducts sometimes do not close completely and need to be treated with other methods such as sutures.
Argon knife (argon beam coagulators): The high-energy beam generated when argon gas is passed through the electrode is used to cut liver tissue and coagulate small vessels to stop bleeding. Argon gas flow 2-7L/rain, nozzle more than 1cm from the cutting surface. It can make the tissue crust and carbonize, forming a 3mm thick crust on the liver cut surface, and can make the blood vessels less than 2mm in diameter coagulate to achieve the purpose of rapid hemostasis, which is a more effective method to control the bleeding of liver wound, especially for the hemostasis of diffuse bleeding of liver wound. Because the argon knife is non-contact heat transfer, it greatly reduces the damage to the liver vessels and bile ducts. During surgery, if a large blood clot has formed on the liver trauma, the hydrogen knife will form a crust on the blood clot and fail to achieve hemostasis because the low-flow argon gas cannot blow it away, and the blood clot must be removed first by attraction. Because argon gas flow can increase the intra-abdominal pressure, intra-abdominal pressure should be monitored during the operation, and the gas flow should be adjusted in time to prevent high intra-abdominal pressure from causing respiratory and circulatory dysfunction. Excessive argon flow may also lead to tumor metastasis and air embolism formation. Therefore, some scholars do not advocate the application of argon knife in LH.
CUSA (cavitron ultrasonic surgical aspirator, CUSA): It is a full-frequency ultrasonic emulsion suction knife, referred to as super suction knife, which uses the “cavitation effect” of low-frequency ultrasound (frequency of 25KHZ and 35KHZ) to selectively crush and separate tissues. The ultrasonic suction knife is used to selectively crush and separate tissues by the “cavitation effect” of low frequency ultrasound (25KHZ and 35KHZ). During hepatobiliary tumor surgery, the suction knife can selectively crush liver cells without damaging blood vessels and bile ducts. Therefore, it helps the surgeon to safely separate the blood vessels and bile ducts, thus greatly reducing the degree of tissue damage.
The Endo-GIA is safe, reliable and easy to use, especially for thick intrahepatic ducts. However, if the liver section is too thick (>1.5 cm) or if the Endo-GIA is used blindly without anatomical and laparoscopic ultrasound confirmation of the location of the large intrahepatic vessels, there is a risk of incomplete or unsound vessel clamping, causing hemorrhage. Endo-GIA is expensive and is more often used in conjunction with the above methods for dissection of larger vessels or bile ducts.
The endoscopic multifunctional surgical dissector (PMOD), which combines four functions of scraping, blunt cutting, suction and electrocoagulation, can dissect the intrahepatic ductal structures and treat them with electrocoagulation or clamping depending on the thickness of the ducts. Simultaneous suction allows timely aspiration of liver tissue debris, accumulated blood, fluid and smoke from electrocautery to ensure a clear operative field [22]. Because this tool can perform various operations of hepatectomy, such as the dissociation of perihepatic ligament, scraping and suction of hepatic cut edge, electrocoagulation and cutting of blood vessels, simultaneous suction, and frequent replacement of surgical instruments are not needed during the operation, it is a cheap and practical tool with a good prospect of use.
4.Technical points
(1) Anesthesia: general anesthesia with tracheal intubation. Routinely put elastic bandages on both lower limbs to prevent the formation of venous thrombosis in the lower limbs during and after surgery. Routinely check the arterial blood gas during the operation, and adjust the anesthetic oxygen flow according to the results. If the operation is expected to be large, arterial blood pressure should be monitored.
(2) Trocar placement and operation space establishment: A 10-mm Trocar is placed 1 to 2 cm around the umbilicus as an observation hole, a CO2 pneumoperitoneum is established, and intra-abdominal pressure is set at 12 mmHg or less. In the case of left hemihepatectomy or left lobectomy, this hole is chosen to the left of the umbilicus, which allows the lens to reach the top of the diaphragm. The rest of the holes are located below the glabella, below the ribs on the midclavicular line and on the anterior axillary line, and the specific position should be adjusted appropriately according to the lesion site and the patient’s body shape. Generally, four to six Trocar holes with an internal diameter of 5 mm to 12 mm need to be placed in the upper abdomen. the principles of hole placement are: the operative field is as large as possible, the main operating hole is as close to the lesion as possible without interfering with the operation, and the auxiliary holes do not interfere with the operation. The subcostal margin perforation holes are connected as straight as possible to help the incision to be straight when changing the abdomen. The key to laying out the holes is to choose a good puncture point suitable for the operation of ultrasonic knife and linear cutter, so that their operation direction is as much as possible in line with the direction of the proposed liver incision line.
(3) Exploration: The abdominal cavity should be fully explored first, and then the liver and and adjacent organs should be explored. If it is a tumor lesion, it needs to include the tumor site, size, number, whether there are metastases on the liver surface, whether the hilar lymph nodes are enlarged, whether the tumor is adherent to the surrounding organs and the degree of liver cirrhosis. If necessary, intraoperative laparoscopic ultrasound will be used to further investigate the location, size, boundary and blood supply of the tumor to help judge the possibility of tumor resection and select a feasible surgical plan.
(4) LH general surgery steps: ①Progressively free the liver, determine the surgical plan according to the exploration results, and draw a pre-cut line on the liver surface with an electric knife. ②Inflow duct dissection and control. Irregular resection should try to find out the main donor vessels and cut them off after clamping with titanium clips; regular hepatectomy should be blocked by dissecting the corresponding liver tips. ③Outflow duct dissection and control; this step can be waived for small hepatectomies. Large hepatectomy should dissect the second hepatic hilar and pre-block the corresponding hepatic vein. ④The combined application of ultrasonic knife, linear cutting closure, electric knife and other instruments should be used to gradually sever the liver, where the larger ducts are closed with titanium clips. ⑤ The hepatic section was carefully hemostatic, and the wound was closed with bioprotein gel if necessary. ⑥The laparoscopic ultrasound was used to explore the presence of residual tumor and the blood supply to the remaining liver (mainly whether the hepatic veins were patent). (7) Put the specimen into a disposable retrieval bag and remove it completely through the enlarged puncture hole (about 1/2 the diameter of the specimen); and immediately cut open the specimen to check whether the tumor is completely removed and whether the resected area meets the radical standard. If necessary, send intraoperative freezing examination for further confirmation. (8) Rinse the abdominal cavity and place drainage tubes at the operation site and ventouse.
5.Main complications and prevention points
(1) Intraoperative bleeding
Intraoperative bleeding is often the main reason for failure of laparoscopic hepatectomy, and control of bleeding is the key to successful laparoscopic hepatectomy. Our experience is: ①For the blood supply of each segment of the left hepatic hemiport, it can be dissected out separately at the sagittal hilar, and the hemiportal blood flow can be blocked by clamping or ligating as needed, without blocking the total hilar blood flow. (②For the structures of the left hepatic segments into the hepatic vasculature, it is clearer to dissect and separate them outside the Glisson sheath, and the branches of the three structures of portal vein, hepatic artery and bile duct can be effectively controlled by clamping them together with titanium clips or absorbable biological clips, or by disconnecting them with linear cutting anastomoses. (iii) For both left and right hepatic veins, the trunk can be dissected and isolated laparoscopically, and after isolation of the trunk, it can be closed with a titanium clip. The hepatic vein is usually severed at the end of the hepatic parenchymal dissection with titanium clamps or with a linear cutting anastomosis. Before spraying medical bioprotein gel or covering hemostatic gauze on the hepatic section, it is beneficial to dip the hepatic section in gauze to prevent poor adhesion of bioprotein gel or too rapid dissolution of hemostatic gauze, which can affect the hemostatic effect.
(2) 52 CO2 air embolism
CO2 gas embolism usually occurs when the hepatic vein is injured, and the high-pressure CO2 gas enters the heart in large quantities with the hepatic vein, which is one of the biggest causes of death during laparoscopic hepatectomy. In animal experiments, a floating catheter was placed via the inferior vena cava and the hepatic vein was blocked with a balloon to prevent the occurrence of intraoperative CO2 gas embolism. It was suggested that dissecting the hepatic vein outside the liver before parenchymal dissection and clamping it with a titanium clip could prevent the formation of CO2 emboli in the hepatic vein. However, the authors also pointed out that dissection of the hepatic vein outside the liver is very dangerous and can cause death within a short period of time if not handled properly.
In addition, LH under pneumoperitoneum-free conditions is a good way to control CO2 pneumothorax, but this method requires certain instruments and the surgical exposure is not as good as conventional laparoscopy, so it is not widely performed.
6. Evaluation of LH
Numerous studies have shown that LH is comparable to open hepatectomy (OH) in terms of bleeding, transfusion rate, complication rate, and mortality; it is significantly better than OH in terms of time to deflation and feeding, analgesic use, length of hospital stay, return to work, and satisfaction, while the operative time is slightly longer and the cost of surgery is higher. These studies suggest that LH is safe and feasible. Wang Gang et al. compared the costs of LH and OH, showing that the direct costs of LH were higher but the indirect costs were lower, and the total costs were slightly lower than those of OH, indicating that LH has good economic benefits.
7. Problems and outlook
The primary problem is that liver resection devices need to be further improved. Although new hepatic dissection devices keep appearing, they all have deficiencies and cannot achieve the ideal hepatic dissection effect, especially it is difficult to control hemostasis during hepatic dissection; in addition, they are generally expensive and not suitable for our national conditions, so it is difficult to promote popularization. Therefore, the next rapid development of LH must depend on the emergence of new liver resection devices.
Second, due to the limitations of laparoscopic surgery, lesions in certain parts of the liver (e.g., caudate lobe, above and behind the hepatic diaphragm surface, etc.) are limited in performing LH. Some authors have proposed to manage tumors above and behind the hepatic diaphragmatic surface by combined thoracoscopy, but this method adds additional incisions in the chest and diaphragm, and the surgical operation is complicated and has not been widely performed.
In addition, although the results of some domestic and international studies have shown that LH is safe and feasible for the treatment of malignant disease. However, due to the lack of long-term randomized controlled studies, laparoscopic techniques for the treatment of malignant tumors remain controversial, with the main focus on the degree of thoroughness of lymph node dissection, intraoperative tumor-free operation technique, tumor implantation in the incision, and the impact on the patient’s near and long-term survival. It is generally accepted that attention to tumor-free operation techniques, reduction of pneumoperitoneum pressure, and application of specimen bags can effectively reduce the chance of tumor implantation and metastasis.
In conclusion, although LH has shown its advantages and has been greatly developed, it is still in the exploratory stage. As China is a country with a high incidence of liver diseases (liver cancer and stones), it is believed that LH will have a broad application prospect as the technology continues to mature and the instruments continue to improve.