A point-based objective scoring tool using surgical videos for grading difficulty levels of laparoscopic cholecystectomy

In the operating room, a surgeon's hands move with precision, but the path they take is rarely the same for every patient. A laparoscopic cholecystectomy, the procedure to remove the gallbladder through small incisions, is one of the most common surgeries performed worldwide. For some patients, the organ sits quietly, easy to lift and remove. For others, years of inflammation or infection have turned the area into a tangled mess of scar tissue and fluid, making the task significantly harder. This variability creates a problem for the medical community: how do you fairly judge a surgeon's skill when one operation is a simple walk in the park and another is a climb up a sheer cliff? Traditional ways of measuring difficulty often rely on how long the surgery took or whether the surgeon had to switch to a larger, open incision. However, these measures are flawed because they depend heavily on the surgeon's own experience, the skill of their assistants, and even the quality of the equipment, rather than the actual challenge presented by the patient's body.

To solve this, researchers at Northern Health and the University of Melbourne set out to create a new way of grading these surgeries. They wanted a system that looked only at what could be seen on the video screen during the operation, ignoring everything else. By focusing strictly on visual evidence, they aimed to build a standard ruler that could measure the difficulty of a case objectively, regardless of who was performing the surgery. This approach is crucial for training new surgeons and for research, as it allows experts to compare performances on a level playing field. It also opens the door for future technology, where computer programs could one day watch these videos and grade the difficulty automatically, removing human bias entirely.

The team began by gathering eighty anonymous video recordings of these gallbladder removals. They selected only videos taken using a specific four-port technique where the patient lies on their back, ensuring the view was consistent. Three expert surgeons, who specialize in liver and bile duct operations, watched these videos to rate the difficulty. Before they started, the experts were trained using two example videos that were not part of the study, ensuring they all understood what to look for. The researchers had previously reviewed existing grading systems and decided to focus entirely on real-time visual features, such as how the gallbladder looked, how hard it was to move, and what obstacles appeared during the procedure.

The experts watched the videos and classified each case as mild, moderate, or severe. They looked for specific signs, such as whether the gallbladder was buried under layers of sticky scar tissue, if the organ was so swollen or damaged that it could not be grabbed with surgical tools, or if the surgeons had to drain fluid to make the area safer to work in. The team found that the experts agreed very well on most of these visual signs. Five of the criteria they used were rated as having excellent agreement, meaning the experts almost always saw the same thing, while four others showed good agreement. No criteria were considered poor, suggesting that these visual clues are reliable and can be spotted by different people in the same way.

When the researchers compared the videos labeled as "severe" against those labeled as "mild," clear patterns emerged. The difficult cases were far more likely to have the gallbladder completely covered in adhesions, which are bands of scar tissue that glue organs together. In the severe group, thirteen percent of the cases had the gallbladder fully buried, compared to just one percent in the mild group. The experts also noted that in the hardest cases, the wall of the gallbladder was often thickened, and the organ itself showed signs of severe infection or gangrene. Perhaps most telling was the physical struggle to handle the organ; in nearly half of the severe cases, the surgeons could not grasp the gallbladder at all, a problem that never occurred in the mild cases. In two-thirds of the severe cases, the surgeons had to perform a decompression, which involves draining fluid from the gallbladder to reduce its size and pressure before they could proceed.

To turn these observations into a usable tool, the team used statistical methods to figure out which factors were the most important. They noticed that some signs, like a thickened wall or signs of gangrene, often appeared together, so they focused on the factors that stood out as independent predictors of a difficult surgery. They found that having the gallbladder completely buried in scar tissue was a major warning sign. Even more significant was the inability to grasp the organ or the need to drain it. The researchers assigned points to these factors based on how strongly they predicted a difficult case. For instance, the need to decompress the gallbladder was given the highest weight, while the presence of a stone stuck in the neck of the organ was also a key factor.

The result was a simple scoring system where a surgeon or researcher could watch a video, check for these specific visual signs, and add up the points. If the score reached a certain level, the case was classified as severe. The team tested this system and found it worked well. When they used a cutoff score of three, the tool correctly identified severe cases most of the time. When they lowered the cutoff to one, it successfully identified moderate cases as well. This means the system can distinguish between easy, medium, and hard surgeries with a high degree of accuracy, based purely on what is visible in the video.

This study does not claim to have solved every problem in surgical assessment, and it acknowledges some limits. The researchers only looked at the part of the surgery inside the abdomen, so they did not include the time it took to insert the instruments or the positioning of the patient. They also relied on the subjective judgment of three expert surgeons to define what "severe" meant, rather than comparing their results to patient outcomes like recovery time. However, the strength of their work lies in its objectivity. By stripping away factors like the surgeon's experience or the time of day, they created a framework that focuses entirely on the patient's anatomy and the immediate challenges of the operation.

The implications of this work extend beyond just grading a single surgery. By proving that experts can agree on what makes a case difficult just by watching a video, the researchers have laid the groundwork for the next generation of surgical tools. If a human can reliably spot a buried gallbladder or a stuck stone on a screen, a computer program might eventually be able to do the same. This could lead to artificial intelligence systems that watch surgeries in real-time, alerting surgeons to potential difficulties or providing automated feedback for training. For now, this point-based tool offers a clear, reproducible way to measure the true difficulty of a laparoscopic cholecystectomy, ensuring that the assessment of surgical skill is based on the reality of the operation, not on the circumstances surrounding it.