Prevalence of anatomic landmarks for orientation during elective laparoscopic cholecystectomies

The difficult laparoscopic cholecystectomy: a narrative review

BACKGROUND/PURPOSE

Laparoscopic cholecystectomy is one of the most commonly performed general surgical procedures. Difficult laparoscopic cholecystectomy is associated with increased operative time, hospital stay, complication rates, open conversion, treatment costs, and mortality. This study aimed to provide a comprehensive literature review on difficult laparoscopic cholecystectomy.

METHODS

A literature search was conducted for articles published in English up to June 2024 using common databases including PubMed/MIDLINE, Web of Science, Google Scholar, and ScienceDirect. Keywords included "safe laparoscopic cholecystectomy", "difficult laparoscopic cholecystectomy", "acute cholecystitis", "prevention of bile duct injuries", "intraoperative cholangiography," "bailout procedure," and "subtotal cholecystectomy". Only clinical trials, systematic reviews/meta-analyses, and review articles were included. Studies involving children, robotic cholecystectomy, single incision laparoscopic cholecystectomy, open cholecystectomy, and cholecystectomy for indications other than gallstone disease were excluded.

RESULTS/DISCUSSION

Emergency laparoscopic cholecystectomy for acute cholecystitis is ideally performed within 72 h of symptom onset, with a maximum window of 7-10 days. Intraoperative cholangiography can help clarify unclear biliary anatomy and detect bile duct injuries. In the "impossible gallbladder", laparoscopic cholecystostomy or gallbladder aspiration may be considered. When dissection of Calot's triangle is deemed hazardous or impossible, the fundus-first approach allows for completion of the procedure with either total cholecystectomy or subtotal cholecystectomy. Subtotal cholecystectomy is effective in preventing bile duct injuries, can be performed laparoscopically, and is currently the best available bailout approach for difficult laparoscopic cholecystectomy.

CONCLUSION

Difficult laparoscopic cholecystectomy is a common clinical scenario that requires a judicious approach by experienced surgeons in appropriate settings. When difficult laparoscopic cholecystectomy is encountered, various bailout strategies are available. Currently, subtotal cholecystectomy is likely the most effective bailout approach.

When Critical View of Safety Fails: A Practical Perspective on Difficult Laparoscopic Cholecystectomy

The incidence of common bile duct injuries following laparoscopic cholecystectomy (LC) remains three times higher than that following open surgery despite numerous attempts to decrease intraoperative incidents by employing better training, superior surgical instruments, imaging techniques, or strategic concepts. This paper is a narrative review which discusses from a contextual point of view the need to standardise the surgical approach in difficult laparoscopic cholecystectomies, the main strategic operative concepts and techniques, complementary visualisation aids for the delineation of anatomical landmarks, and the importance of cognitive maps and algorithms in performing safer LC. Extensive research was carried out in the PubMed, Web of Science, and Elsevier databases using the terms "difficult cholecystectomy", "bile duct injuries", "safe cholecystectomy", and "laparoscopy in acute cholecystitis". The key content and findings of this research suggest there is high intersocietal variation in approaching and performing LC, in the use of visualisation aids, and in the application of safety concepts. Limited papers offer guidelines based on robust data and a timid recognition of the human factors and ergonomic concepts in improving the outcomes associated with difficult cholecystectomies. This paper highlights the most relevant recommendations for dealing with difficult laparoscopic cholecystectomies.

Morphology of the sulcus of the caudate process (Rouviere's sulcus) in a Greek population and a systematic review with meta-analysis

The purpose of this study was to determine the prevalence and to investigate the morphology of the sulcus of the caudate process in a Greek population, along with a systematic review and meta-analysis of the literature. Overall, 103 consecutive patients undergoing laparoscopic cholecystectomy were included in the analysis. The sulcus was present in 91% and three morphological variants were identified (groove 69%, slit 21% and scar 10%). The sulcus had a horizontal course in 90% of patients and a mean length of 25 ± 13 mm. The meta-analysis included 27 surgical and 11 cadaveric studies with 6661 cases in total. The pooled prevalence of the sulcus was 80% and did not differ significantly among various geographical regions. Concerning sulcus subtypes, the binary "open/fused" classification was used to unify the heterogeneous data. The "open" type was more frequent than the "fused" (64.5% vs 35.5%). A horizontal course was observed in 53.5% and an oblique in 45.7%. The sulcus contained the right portal pedicle in 38%, the right posterior portal pedicle in 37%, and the right posteroinferior pedicle in 23.5%. In conclusion, the sulcus of the caudate process is a very helpful anatomical landmark in hepatectomy and laparoscopic cholecystectomy and can be identified in the majority of patients. However, various classifications for the morphological variants and diverse terminology cause discrepancy in the literature and create the need for a single classification system. The proposed 3-tier classification (groove, slit, scar) is simple and easy to remember and avoids ambiguous nomenclature.

The inferior boundary of dissection as a novel landmark for safe laparoscopic cholecystectomy

BACKGROUND

Since the introduction of laparoscopic cholecystectomy over 30 years ago, rates of bile duct injury have remained elevated compared to the era of open cholecystectomy. We propose an anatomical landmark, the Inferior Boundary of Dissection, to help prevent dangerous dissection in the porta hepatis and provide clues as to when a critical view of safety may not be immediately achieved.

METHODS

This landmarking approach is based on fundamentals of biliary anatomy and surface landmarks of the liver.

RESULTS

The 'Boundary' extends from Rouviere's sulcus to the junction of the peritoneum and fat overlying the cystic and hilar plates, near the base of segment 4. This anatomic landmark represents the lower boundary for safe dissection, by outlining the location of the biliary pedicles.

CONCLUSION

The two points of reference are reliable surface landmarks with predictable and consistent relationships to the biliary pedicles. It also serves as a line above which the gallbladder can be opened or mobilized in a 'top-around' approach, facilitating subtotal cholecystectomy when the hepatocystic triangle appears hostile due to inflammation. The landmark has been well-received in our region as a facile instrument for safe cholecystectomy and we advocate for its broader use.

The R4U Planes for the Zonal Demarcation for Safe Laparoscopic Cholecystectomy

Post-cholecystectomy bile duct injury is a serious complication. Usually, it results from structural misidentification and can be avoided by adopting the critical view of safety. The biliary, vascular, and other visceral injuries can also occur during the dissection to achieve the critical view of safety. To avoid such complication, identification of the safe area for dissection is important during laparoscopic cholecystectomy. It is imperative to start the dissection in a safe area and remain there during the procedure. Fixed anatomical landmarks can help in proper orientation to ascertain the surgical anatomy correctly during surgery. The Rouviere's sulcus is one of such anatomical landmarks. Utilizing this sulcus, we describe a technique of zonal demarcation based on the concept of one line (the R4U line), two planes (the R4U planes), and four zones to identify a "safe area" for dissection during laparoscopic cholecystectomy to perform the procedure safely.

Is an optical illusion the cause of classical bile duct injuries?

We sought to determine if lateral–inferior traction on the Hartmann pouch could produce bile duct kinking and subsequent misinterpretation of the space on the left side of the bile duct as the hepatobiliary triangle. Once traction was applied, we measured the angle between the cystic duct and inferior gallbladder wall (hepatobiliary triangle) in 76 cases, and the angle between the common bile duct and common hepatic duct (porta hepatis “triangle”) in 41 cases. The mean angles were significantly different (hepatobiliary triangle mean 68.2°, standard deviation [SD] 16.0°, range 23–109°; porta hepatis “triangle” mean 112.0°, SD 18.4°, range 72–170°; p < 0.01). The ranges, however, overlapped in 26 cases. In many cases, lateral–inferior traction on the Hartmann pouch produced substantial kinking of the bile duct that could easily elicit the illusion that it is the hepatobiliary triangle rather than the centre of the porta hepatis.

The evaluation of B-SAFE and ultrasonographic landmarks in safe orientation during laparoscopic cholecystectomy

INTRODUCTION

Even though the prevalence of bile duct injury (BDI) is nowadays lower than before and close to the era of open cholecystectomy, there is a strong need to make it even lower. B-SAFE is a group of five visual landmarks that may be used before dissection in the hepatocystic triangle for better orientation around the gallbladder. Another method is laparoscopic ultrasound (LUS), which enables confirmation of structures in the hepatoduodenal ligament and delineation of the safe plane of dissection.

AIM

To evaluate the use of B-SAFE and ultrasonographic landmarks during laparoscopic cholecystectomy in navigation around the gallbladder.

MATERIAL AND METHODS

The study group consisted of 158 patients with symptomatic cholecystolithiasis. The methods of intraoperative orientation around the gallbladder attempted in every patient during laparoscopic cholecystectomy included B-SAFE and ultrasonographic landmarks.

RESULTS

The identification rate of ultrasonographic landmarks - the upper border of "Mickey Mouse" sign (MMS) (the equivalent of the Rouviere's sulcus), the bile duct, and the hepatic artery - was significantly higher in patients with body mass index ≥ 30 kg/m2 and fibrosis and chronic inflammation in the gallbladder neck than B-SAFE. LUS was also significantly more successful in the identification of the bile duct in the whole study group than B-SAFE. There were no significant differences according to the identification of the duodenum. The conversion rate was 2.6%, and we did not observe any BDI.

CONCLUSIONS

Visual landmarks defined in B-SAFE are not as reliable as ultrasonographic landmarks; thus, LUS should be taken into consideration in the first place as a method of navigation around the gallbladder.

The sulcus of the caudate process (Rouviere's sulcus): anatomy and clinical applications-a review of current literature

The sulcus of the caudate process is a horizontal groove on the inferior face of the liver. Its prevalence has not previously been determined. Because of its location, it represents a helpful extra-biliary landmark that could be used in biliary surgery to decrease bile duct injury. The goal of this study is to determine the prevalence of Rouviere's sulcus and describe its anatomy and relevant surgical applications. We conducted a literature review on the various characteristics of the sulcus, selecting anatomical clinical studies and dissections. We performed 10 cadaveric dissections in the Laboratory of Anatomy at Purpan University to determine the contents. We selected 12 anatomical studies, conducted between 1924 and January 1st, 2020, which included 2394 patients. The prevalence of the sulcus is 78.24% ± 9.1. Classification of Singh was used to describe anatomical characteristics. Type I ("deep sulcus") was identified in 50.4% ± 9.8 of cases, mostly consisting of Type Ia (open). Type II ("slit-like") was estimated to account for 13.3% ± 13.2, whereas Type III ("scar") described 12.3% ± 8.0. Average dimensions were estimated for length (26 mm ± 5.7), width (6.5 mm ± 1.5), and depth (7.9 mm ± 1.75). The content of the sulcus consists of the right portal vein and its division, the right hepatic artery, along with the right hepatic bile duct. The sulcus determines the orientation of the common bile duct. The sulcus of the caudate process is a reliable extra-biliary landmark, which presents a useful tool for reducing bile duct injuries during hepatobiliary surgery.

Development of an artificial intelligence system using deep learning to indicate anatomical landmarks during laparoscopic cholecystectomy

BACKGROUND

The occurrence of bile duct injury (BDI) during laparoscopic cholecystectomy (LC) is an important medical issue. Expert surgeons prevent intraoperative BDI by identifying four landmarks. The present study aimed to develop a system that outlines these landmarks on endoscopic images in real time.

METHODS

An intraoperative landmark indication system was constructed using YOLOv3, which is an algorithm for object detection based on deep learning. The training datasets comprised approximately 2000 endoscopic images of the region of Calot's triangle in the gallbladder neck obtained from 76 videos of LC. The YOLOv3 learning model with the training datasets was applied to 23 videos of LC that were not used in training, to evaluate the estimation accuracy of the system to identify four landmarks: the cystic duct, common bile duct, lower edge of the left medial liver segment, and Rouviere's sulcus. Additionally, we constructed a prototype and used it in a verification experiment in an operation for a patient with cholelithiasis.

RESULTS

The YOLOv3 learning model was quantitatively and subjectively evaluated in this study. The average precision values for each landmark were as follows: common bile duct: 0.320, cystic duct: 0.074, lower edge of the left medial liver segment: 0.314, and Rouviere's sulcus: 0.101. The two expert surgeons involved in the annotation confirmed consensus regarding valid indications for each landmark in 22 of the 23 LC videos. In the verification experiment, the use of the intraoperative landmark indication system made the surgical team more aware of the landmarks.

CONCLUSIONS

Intraoperative landmark indication successfully identified four landmarks during LC, which may help to reduce the incidence of BDI, and thus, increase the safety of LC. The novel system proposed in the present study may prevent BDI during LC in clinical practice.