Advanced laparoscopic HPB surgery: Experience in Seoul National University Bundang Hospital

Abstract The worldwide trend in surgery has moved from open surgery to minimally invasive surgery. Likewise, the application of minimally invasive surgery in the hepato‐pancreato‐biliary (HBP) field is also rapidly expanding. The field of HBP surgery can be divided into liver, pancreas and biliary fields. Minimally invasive liver surgery is recently developed. However, laparoscopic liver resection in difficult areas is challenging. However, with the accumulation of experiences, laparoscopic liver resection for difficult areas is performed more than before. With more propagation, more and more liver resection will be performed by laparoscopic approach. In minimally surgery for the pancreas, distal pancreatectomy has become a well‐recommended procedure in benign and borderline malignancy. There have been several systemic reviews that show advantages of laparoscopic distal pancreatectomy. The reports on laparoscopic pancreaticoduodenectomy (PD) are slowly increasing in spite of technical difficulty, with several systemic reviews showing advantages of the procedure. However, more PD will be performed as robotic‐assisted procedures in the future. The laparoscopic surgery for biliary tract malignancy is still in early stages. The laparoscopic surgery for gallbladder cancer has been contraindicated, although there have been encouraging reports from expert centers. The laparoscopic surgery for Klatskin tumor is still an experimental procedure. Robotic‐assisted procedures for the surgery of cholangiocarcinoma will be the future. Robotic‐assisted surgery for the HBP field is still not well‐developed. However, with the necessity of more precise manipulation like intracorporeal suturing, robotic‐assisted surgery will be used more often in the field of HBP surgery.

tions from the meeting, practical guidelines for performing liver resection focusing on the technical issues of LLR have also been reported. 3 With the advancement of laparoscopic surgical skills and equipment technologies, the indications of LLR are gradually expanding.
As experience in performing more complex procedures grows, procedures which were considered to be relative contraindications, like unfavorable locations in the postero-superior segments, were more performed than before. And with the accumulation of the evidence to support safety of LLR in major hepatectomies and anatomical resections, the number of reports on advanced LLR is also increasing.
For LLR to be accepted as standard in these surgeries, the procedure Resection of posterior superior segment is another unfavorable location as it is one of the most difficult parts on which to performing a laparoscopic procedure. In a study comparing posterior superior to anterior lateral segments, laparoscopic approach for posterior superior segment is not inferior to surgery for anterior lateral segment. 6 Subsequent reports on comparative analysis by case match analysis between posterior superior segment and anterior lateral segment, there was no difference in overall survival and disease-free survival. 7 Even though posterior superior is a more difficult procedure, survival outcome appears to be similar between the two groups.
For the minimally invasive surgery for posterior superior lesion, selective use of intercostal trocars can be useful for good operative view. Furthermore, this intercostal trocar facilitates parenchymal resection and bleeding control when posterior superior segment resection is perfromed. 8,9 Many laparoscopic surgeons have been using this intercostal/transdiaphragmatic trocar when performing resections in the posterior superior segments without any major complications associated with the procedure. [10][11][12] Centrally located tumors also pose significant technical challenges due to their difficult location. When performing resection for tumor at central lesion, there is high risk of massive bleeding from injury of adjacent vessels. There are reports on LLR for centrally located tumor, which were very close to the hilum or major hepatic vein and inferior vena cava. 13 The patients were mostly cases of HCC and the operations performed ranged from right posterior sectionectomy, central bi-sectionectomy, and left major hepatectomy including four caudate lobe resections. When compared with open surgery, there is no difference in survival between laparoscopic surgery and open surgery. Therefore, even for centrally located tumor, laparoscopic resection can be cautiously applied.
Anatomic liver resection is a very important concept in the management of HCC. HCC is usually associated with underlying poor liver function because of chronic liver disease and cirrhosis. And the resection of only the involved segment is beneficial for the patient as it preserves the volume of the remnant liver. The techniques of anatomical liver resection using the Glissonian pedicle approach have proven to be very useful in laparoscopic surgery. Utilizing these concepts, any types of laparoscopic anatomic liver dissection can be possible depending on tumor locations and remnant liver. 14 The importance of meticulous dissection during liver resection has been highlighted by the impact of remnant liver ischemia as a prognostic factor for survival. The study comparing two groups with minimal remnant liver ischemia and severe remnant liver ischemia showed a big difference in overall survival and disease-free survival. 15 Therefore, it is important to perform precise parenchymal resection to minimize remnant liver ischemia. This technique will increase the safety of the operation and the survival as well. In conclusion, owing to technical development and accumulating experiences, advanced laparoscopic liver resections are being performed more often than before, and the limitations brought about by unfavorable locations may be slowly lifted resulting in anatomic liver resection being performed even more widely in the future.

| Laparoscopic pancreatic surgery
The use of laparoscopic pancreatic resection has gradually grown in  (Table 1) including a difficulty scoring system in laparoscopic distal pancreatectomy. 22 Laparoscopic pancreatoduodenectomy, on the other hand, is a highly demanding procedure and is still being performed by very few surgeons in highly experienced centers. Our initial experience of laparoscopic pancreaticoduodenectomy (PD) was between 2004 and 2006, where we reported eight cases, but, considering the difficulties and post-operative complications associated with the procedure, the procedure's implementation was restricted. 23 But in 2012, the publication of many good reports which showed significant advantage in lymph node harvest in laparoscopic procedure when compared to open surgery further enhanced its potential benefits, encouraging surgeons to carry out total laparoscopic PD. 24 But, considering the technical difficulties associated with the use of long instruments during resection, one way of utilizing the benefits of laparoscopic resection may be laparoscopy-assisted pancreatoduodenectomy. 25 This allows for the resection to be performed by laparoscopy and the reconstruction performed by minimal invasion. This may aid in decreasing the morbidity of PD as operative stress can be minimized with minimal manipulation of the organ and minimal exposure out to air. So, until the universal use of laparoscopic PD is established, laparoscopic-assisted PD may be a stepping stone for further development. Table 2

| Laparoscopic biliary surgery
Regarding biliary surgery, laparoscopic cholecystectomy for benign gallbladder disease has been the landmark procedure in terms of its rapid propagation as a universally accessible and feasible technique performed all over the world. Laparoscopic surgery had been We reported about five cases of lap liver resection for hilar cholangiocarcinoma 3 years ago which is a very difficult and challenging operation. 31 Laparoscopy has some limitation for hilar lesion resection because of the need of bilioenteric reconstruction, which may be better performed using a robot. Ultimately, with gathering evidence, in advanced laparoscopic HPB surgery, robots will play a significant role in the future.

| CON CLUS ION
Minimally invasive surgery has showed a lot of promise in the field of hepato-pancreato-biliary surgery. With advancing technology, expertise and experience, more and more advanced HPB procedures will be performed by minimally invasive surgery and we expect robotic surgery to play a significant role in the future.