History of laparoscopic hepatectomy
Laparoscopic liver resection was performed as a minimally invasive surgery in 1993, but looking back at that time, it was far from becoming widespread. In 2007, the Endoscopic Liver Surgery Study Group was established to promote the spread of laparoscopic liver resection, and the number of facilities and cases introducing laparoscopic liver resection has steadily increased.
１．After the insurance coverage in 2010
Partial hepatectomy and lateral segment resection were covered by insurance in 2010, and the number of laparoscopic liver resection cases increased rapidly. Most of the target diseases are primary liver cancer and metastatic liver cancer, but the proportion of liver metastases from colorectal cancer has been increasing. This is thought to reflect the increasing use of laparoscopic liver resection as a suitable surgical method, as oncological goals are often achieved through partial hepatectomy in surgical treatment of colorectal cancer liver metastases. In recent years, when comparing open and laparoscopic surgery, rather than emphasizing minimal invasiveness, reports have also been given on reduced postoperative complications and non-inferior long-term prognosis.
The results of many meta-analyses have been reported, with less bleeding and complications, faster recovery after surgery, and shorter hospital stay, and in terms of long-term prognosis, 5-year survival rate and recurrence-free survival are superior to open liver resection. In most cases, there was no difference. However, the evidence level was still low.
On the other hand, laparoscopic liver resection is more difficult than normal open surgery, and it takes more time to master the technique. It was also recognized that it is important to consider the indications more carefully, taking into account the surgeon’s own surgical skills for each case. In recent years, the difficulty of laparoscopic liver resection procedures has been scored based on five items: tumor location, resection method, tumor diameter, relationship with major blood vessels, and liver function, and cases are selected according to the operator’s experience. An evaluation method has been proposed and its effectiveness has been demonstrated.
２．The Endoscopic Liver Surgery Study Group Hands-On Seminar
As laparoscopic liver resection became more widespread, mainly at High Volume Centers, there was an urgent need for training for mastering laparoscopic liver resection and the establishment of a system for it. As part of activities aimed at its safe dissemination, the Endoscopic Liver Surgery Study Group Hands-on Seminar was started in 2009 under the auspices of the Japanese Society of Endoscopic Surgery. Over two days, systematic and technical lectures are held, as well as practical training on how to perform this technique safely. So far, 29 sessions have been held, with a total of over 800 participants. As far as I know, Japan is the only country where such systematic training is being attempted on a regular and sustained basis. I am very happy to see that the surgeons who originally took the course are now active as experts.
３．Liver endoscopic surgery technology certification system
In 2004, the Japanese Society of Endoscopic Surgery introduced a technical certification system for endoscopic surgery. Although this is a system based on Professional Autonomy, it also covers liver resection, which is now covered by insurance, and has been implemented since 2012. The target surgical procedure will be complete laparoscopic partial hepatectomy with treatment of intrahepatic vessels, and its basic technique will be evaluated using unedited video. Tumor identification and resection line identification using ultrasound, surgical field development for liver parenchymal resection, selection and use of surgical instruments, bleeding control, vascular exposure and resection, ensuring surgical margins, specimen extraction, etc. This is an evaluation item. Furthermore, cases involving resection in the craniodorsal area of the liver or liver damage are considered to be highly difficult and are subject to additional points.
It can be said that any surgery is based on the selection of appropriate cases and surgical techniques, careful preparation, and reliable execution of basic procedures. This is considered to be an indicator for performing resection. The technical certification system for laparoscopic liver resection itself is only practiced in Japan, and combined with the training mentioned above, it is expected that this system will be disseminated as a system unique to Japan.
４．The early days of laparoscopic liver resection
Although consideration has been given to the acquisition of surgical techniques to ensure safety, in 2014 there was a case in which the expansion of indications to laparoscopic surgery for liver cancer led to unfortunate results due to ethical concerns. It became a major social problem, including the management aspect of the procedure, and some articles appeared in the press denying the procedure itself. However, according to the National Clinical Database and the Japanese Society of Hepatobiliary and Pancreatic Surgery, which conducted an emergency survey on laparoscopic surgery for the liver and pancreas at facilities with a high number of surgical records, the postoperative mortality rate was lower than laparoscopic surgery compared to open surgery. It was not high compared to . In addition, the multicenter Hepatobiliary and Pancreatic Surgery Society Endoscopy Project study, which conducted a propensity score-matched analysis of primary and metastatic liver cancer cases, also found that there was less bleeding compared to open surgery, and recovery was faster, and in cases of primary liver cancer, there were complications after surgery. In addition, there was no significant difference in the oncological prognosis between primary and metastatic liver cancer.
Laparoscopic liver resection is thought to cause less blood loss than open surgery due to the influence of pneumoperitoneum and the effect of magnified vision, although there are technical limitations. Furthermore, the significantly lower postoperative complication rate in the laparoscopic liver resection group for primary liver cancer was inferred to be due to the smaller incisions and fewer mobilizations in patients with chronic hepatitis and cirrhosis.
５．Launch of preoperative prospective registration system and insurance coverage in 2016
Since 2014, there has been an urgent need to dispel the harsh public evaluation of laparoscopic hepatectomy and the misunderstandings and concerns that have caused patients and the public. Therefore, in October 2015, the Endoscopic Liver Surgery Study Group started a preoperative prospective registration system for all cases of laparoscopic liver resection. By ensuring safety for patients, increasing the transparency of new surgical techniques to society, accumulating fair and wide-ranging data, and deepening understanding of the surgical technique, we will be able to ensure correct evaluation of laparoscopic liver resection. This system was started with the aim of disseminating the product safely and securely.
Due to the efforts of this registration system and the good results of multicenter laparoscopic liver resection, all surgical procedures including subsegmental hepatectomy, segmental resection, and hepatectomy were covered by insurance in April 2016. It was decided that it would be done. However, there is a questionable interpretation here, and both the Endoscopic Liver Surgery Study Group and the NCD (National Clinical Database) have made it mandatory to prospectively register patients for subsegmental resection or higher.
The Endoscopic Liver Surgery Study Group’s prospective case registration system allows all patients to register the planned surgical procedure and postoperative course before, after, and at the time of re-hospitalization. It is now possible to share information such as serious adverse events. The progress of the Endoscopic Liver Surgery Study Group’s registry is to be monitored and reported, and the progress is published and updated on the website approximately every six months.
Up to 2018, 9372 laparoscopic liver resection cases have been prospectively registered from 341 registered institutions. It can be seen that approximately 300 cases are performed on average per month. (Table 1) Partial liver resection and lateral segment resection, which have traditionally been covered by insurance, accounted for 78%, and (Table 2) Subsegmental resection, segmental resection, and lobectomy accounted for 22%. The 30-day mortality rate for all surgical procedures was 0.10% (8/7543), and the 90-day mortality rate was 0.23% (17/7543). Additionally, the 30-day mortality rate for the newly covered surgery alone is 0.24% (4/1702), and the 90-day mortality rate is 0.65% (11/1702). (Table 3) The mortality rate was low in all cases, and we believe that laparoscopic liver resection was performed safely. We are currently in the final stage of data cleaning and auditing, and plan to conduct a more detailed analysis including complications and report.
The Endoscopic Liver Surgery Study Group’s prospective registration was completed with surgical case registration until September 2018, after which it was integrated into the NCD registry. We believe that this prospective registration of over 9,000 cases has greatly contributed to the safe spread of this surgical procedure. It is speculated that the above-mentioned questionable interpretation, which was an additional condition for insurance coverage, will probably be removed in the near future, and insurance coverage will be the same as regular open surgery.
６．in conclusion
Although there were many ups and downs in the introduction and testing of laparoscopic liver resection, a new surgical technique, we have come this far with the belief that it can provide patients with the great benefit of being minimally invasive. We hope that this will soon become one of the standard surgical procedures for liver tumors. In the future, in the liver field, we believe that surgical techniques will continue to improve with further improvements in endoscopic surgery models and advancements in imaging, and with the introduction of robotic surgery, this field will further develop.
