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Strategies for Lowering the Rate of Bile Duct Injuries in Laparoscopic Cholecystectomy

REDUCING COMPLICATION RATES

Published in JSLS in October 2003

Dr, G. Kevin Gillian, MD

Laparoscopic cholecystectomy is the modern “gold standard” for gallbladder extraction, but its level of difficulty and morbidity are often underappreciated by referring physicians and patients. The surgical community is quick to point to the humanistic benefit patients derive from a successful laparoscopic cholecystectomy, but quietly fears the consequences of the infrequent, but devastating, bile duct injury (BDI). These complications reached an incidence of 0.4% to 0.8% during early experiences with laparoscopic cholecystectomy [1].

The transition from open to laparoscopic cholecystectomy has involved the incorporation and evaluation of new instrumentation, changing technology, and surgical technique. Each of these areas has continued to evolve along with our parameters for performing laparoscopic cholecystectomy. It should not be surprising that the mechanisms and decisions that result in bile duct injuries are multiple.

It was a plausible and logical argument that the abrupt rise in bile duct injuries associated with the earliest efforts to perform laparoscopic cholecystectomy could be expected to drop significantly once surgeons and residents progressed beyond their own learning curve for this novel technique. Presumably, with proper surgical education and experience, bile duct injuries from laparoscopic cholecystectomy would rapidly be reduced to or below the historically and contemporarily observed rate of 0.06% to 0.2% seen in open cholecystectomy [2-4]. Unfortunately, the data have demonstrated that the rate of BDI has not dropped below that of open cholecystectomy. In fact, studies indicate that the rate of BDI in laparoscopic surgery is approximately fivefold higher than that in open surgery [5,6]. Some have suggested that this complication rate has leveled off and is no longer improving [7]. Why has this operation resisted our efforts to reach a more acceptable complication rate? Certainly, it has not been for a lack of research on laparoscopic cholecystectomy. A Medline review found more than 20000 articles published on the subject in 2001 alone. Perhaps processes in play, unrecognized by surgeons, have prevented us from making progress in our efforts against the learning curve.

Bile duct injuries resulting from laparoscopic cholecystectomies show patterns not often seen in open cholecystectomy. These injuries present earlier and are associated with higher ductal injuries and more persistent bile leaks than their open counterparts [1,8]. When BDI occurs with a concomitant major vascular injury, the morbidity and lethality is significantly worse [9]. Although many BDIs are managed by therapeutic endoscopy or Roux-en-Y hepaticojejunostomy, end-stage liver disease resulting in liver transplantation is also described. The dramatic nature of therapy required to repair BDIs after laparoscopic cholecystectomy has a prolonged and lasting effect on the surgeon and patient. This is illustrated by the fact that in one review 31% of 89 patients undergoing successful repair of a major BDI pursued legal action afterwards [10]. On a basic level, the fact that bile duct injuries associated with laparoscopic cholecystectomy tend to be more serious when they do occur should suggest that fundamental problems exist with this procedure. Have we been pushed into accepting and providing an operation for our patients that is less safe than the one it proposes to replace? After nearly 15 years of effort, can laparoscopic cholecystectomy be made safer?

To improve our results, we need to accurately identify the cause of our mistakes. A review of cases where BDI occurs has identified 2 areas on which to focus: risks associated with equipment choices and surgeon/human errors of interpretation with respect to information being provided from the surgical field. Once points of risk are accurately identified, alternative instrumentation and techniques can be devised and evaluated to improve our outcomes.

Monopolar cautery is a comfortable surgical workhorse, but in a laparoscopic field unrecognized and delayed injury from thermal damage has been associated with significant morbidity. Strictures and delayed bile duct perforation from cautery induced injury can not be identified with intraoperative inspection or cholangiogram [11,12]. The difficulty in controlling lateral spread of thermal injury puts all structures in the Triangle of Calot in harms way during dissection. Relative to monopolar cautery, ultrasonic dissection has been demonstrated to cause significantly less thermal injury to nontargeted tissues. Surgeons familiar with these devices find them nearly indispensable in advanced laparoscopic cases. The multitasking nature of the instrument allows the surgeon to remain visually focused on his work while dissecting, grasping, cutting, and gaining hemostasis [13].

The use of surgical clips early during the dissection in laparoscopic cholecystectomy has expedited control of vessels and ducts, but they have also been implicated in creating complications. Blind clip placement in an effort to control unexpected bleeding can create unintended ductal injury or stricture. Past pointing of clips can cause injury to structures outside of the visualized field. It is possible to place clips completely across the common bile duct, and, as a consequence, it becomes available for misidentification and transection [14,15]. Control of the cystic duct, the artery, or both of these, after the gallbladder is completely free from the liver bed should improve the accuracy of clip placement. This technique is similar to the “top down” technique of open cholecystectomy (Figure 1). An advantageous 360-degree view of the gallbladder and cystic duct is now available for surgical inspection. If a top down technique is adopted, an endo loop can be placed over the gallbladder and then the cystic duct, eliminating the need for clip application. Such a technique would prevent surgeons from inadvertently capturing a major bile duct in their clips while eliminating most cases of anatomic confusion.

Anatomic variation is a known source of difficulty in this operation. Eighteen percent of patents suffering BDI have aberrant bile duct anatomy on review of cholangiograms [16]. The indications for operative cholangiography have been changing. Most surgeons perform what they consider “selective” cholangiograms. The criteria for application most often reflect the need to evaluate the possibility of clinically suspected common bile duct stones or to clarify anatomic confusion. A small statistical reduction in BDI (0.39 vs 0.58%) has been shown when surgeons use intraoperative cholangiography (IOC) as opposed to not performing it.6 Bile duct injuries are more likely to be discovered and perhaps minimized when IOC is completed than if IOC is omitted [17]. Unfortunately, intraoperative cholangiograms have been interpreted as normal by the surgeon in approximately 80% of cases where BDI was later confirmed [15]. Also, an accurately interpreted IOC offers no protection against delayed perforations and strictures. In short, many of the bile duct injuries are sustained during the dissection that precedes the decision to perform IOC.

Many injuries occur as a consequence of misinterpretation of visual cues in the surgical field. A fascinating study by Way and colleagues15 reviewed 252 major bile duct injuries from a unique perspective. They used the cognitive science concepts of visual perception, judgment, and human error to analyze surgeon performance. They concluded that laparoscopic bile duct injuries stem principally from misperception, not errors of skill, knowledge, or judgment. Once accepted, the misperceptions can be so strongly held by surgeons that irregularities are ignored and corrective feedback does not occur. We tend to stick to our first impressions and discount further information from the field during laparoscopic cholecystectomy. The fallout from a single misinterpretation is magnified as we continue to work [15].

Modifications to current techniques of laparoscopic cholecystectomy are required if we are to further reduce the overall rate of BDI. The operation in its current form creates a number of hazards for the surgeon to negotiate. The combination of imperfect visualization of vital structures, and the ability of our instruments to injure nontargeted tissue is the Achilles’ heel of this operation. A willingness to consider equipment changes and alternative dissection methods is necessary if we are to further progress already made with this operation. The top down dissection as discussed above may be a useful surgical alternative and allow us to avoid the “compelling anatomic illusions” that result in misperception and injury during the performance of laparoscopic cholecystectomy [15].