Causes and Prevention bile duct injury
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Causes and Prevention of Laparoscopic BileDuct InjuriesAnalysis of 252 Cases From a Human Factors and CognitivePsychology PerspectiveLawrence W. Way, MD,* Lygia Stewart, MD,* Walter Gantert, MD,* Kingsway Liu, MD,* Crystine M. Lee, MD,*Karen Whang, MD,* and John G. Hunter, MD
From the *Department of Surgery, University of California, San Francisco, California, and Department of Surgery, OregonHealth & Science University, Portland, Oregon
This paper was presented at the 2002 annual meeting of the American Surgical Association
ObjectiveTo apply human performance concepts in an attempt to under-stand the causes of and prevent laparoscopic bile duct injury.
Summary Background DataPowerful conceptual advances have been made in under-standing the nature and limits of human performance. Apply-ing these findings in high-risk activities, such as commercialaviation, has allowed the work environment to be restructuredto substantially reduce human error.
MethodsThe authors analyzed 252 laparoscopic bile duct injuries ac-cording to the principles of the cognitive science of visual per-ception, judgment, and human error. The injury distributionwas class I, 7%; class II, 22%; class III, 61%; and class IV,10%. The data included operative radiographs, clinicalrecords, and 22 videotapes of original operations.
ResultsThe primary cause of error in 97% of cases was a visual per-ceptual illusion. Faults in technical skill were present in only3% of injuries. Knowledge and judgment errors were contrib-utory but not primary. Sixty-four injuries (25%) were recog-nized at the index operation; the surgeon identified the prob-lem early enough to limit the injury in only 15 (6%). In class III
injuries the common duct, erroneously believed to be the cys-tic duct, was deliberately cut. This stemmed from an illusionof object form due to a specific uncommon configuration ofthe structures and the heuristic nature (unconscious assump-tions) of human visual perception. The videotapes showed thepersuasiveness of the illusion, and many operative reportsdescribed the operation as routine. Class II injuries resultedfrom a dissection too close to the common hepatic duct. Fun-damentally an illusion, it was contributed to in some instancesby working too deep in the triangle of Calot.
ConclusionsThese data show that errors leading to laparoscopic bile ductinjuries stem principally from misperception, not errors of skill,knowledge, or judgment. The misperception was so compellingthat in most cases the surgeon did not recognize a problem.Even when irregularities were identified, corrective feedback didnot occur, which is characteristic of human thinking under firmlyheld assumptions. These findings illustrate the complexity of hu-man error in surgery while simultaneously providing insights.They demonstrate that automatically attributing technical compli-cations to behavioral factors that rely on the assumption of con-trol is likely to be wrong. Finally, this study shows that there areonly a few points within laparoscopic cholecystectomy where thecomplication-causing errors occur, which suggests that focusedtraining to heighten vigilance might be able to decrease the inci-dence of bile duct injury.
Bile duct injuries are the main serious technical complica-tion of laparoscopic cholecystectomy.1,2 Data are insufficientto determine precisely the frequency of bile duct injuries, but areasonable estimate is one in 1,000 cases.2 A decade ago, as thetechnique of laparoscopic cholecystectomy was first being
learned by otherwise fully trained, practicing surgeons, theinjury rate was noted to be greater during an individuals firstdozen cases than in subsequent ones.2 This learning curvecontribution is now much less important, for surgical residentslearn the procedure under direct supervision of more experi-enced surgeons.
Presented at the Annual Meeting of the American Surgical Association,April 25, 2002.
Correspondence: Lawrence W. Way, MD, University of California San Fran-cisco, 513 Parnassus Avenue, S-550, San Francisco, CA 94143-0475.
E-mail: firstname.lastname@example.orgAccepted for publication November 2002.
ANNALS OF SURGERYVol. 237, No. 4, 460469 2003 Lippincott Williams & Wilkins, Inc.
Surgeons have always analyzed their technical complica-tions for insights that might be translated into improvedperformance. In the past the information available fromsuch reviews could rarely go much beyond a tabulation ofresults. An understanding of the root causes of technicalcomplications remained elusive. This report takes analysisof technical complications to greater depths, for it integratesthe findings of videotapes of operations involving bile ductinjuries, operative notes dictated after the operation hadbeen completed but before an injury had become apparent,and conceptual tools of human factors research and thecognitive science of human error.
The operations of 252 patients who had major bile ductinjuries during laparoscopic cholecystectomy were ana-lyzed. The patients had been referred to the authors forevaluation or treatment, and the accompanying records werecomplete with respect to operative notes from the initialoperation and any subsequent operations done to repair theinjury. The injuries involved the common bile duct (CBD),common hepatic duct (CHD), lobar hepatic ducts, or seg-mental hepatic ducts. Bile leaks from the gallbladder bedand cystic duct were excluded. Operative notes, pathologyreports, radiology reports, operative x-rays, postoperativex-rays, and 22 unedited videotapes of laparoscopic chole-cystectomies that involved bile duct injuries were analyzedto determine the causes of the injuries and circumstancescontributing to them.
Seventy-seven percent of patients were women and 23%were men. The average age was 46 years (range 1986years). The indications for the operation (i.e., the diagnoses)were chronic cholecystitis, 69%; acute cholecystitis, 29%;gallstone pancreatitis, 2%; and cholangitis, 0.4%.
The injuries were examined within the framework ofhuman error analysis. The surgeons performance was an-alyzed for: 1) perceptual input data (visual and/or haptic), 2)knowledge and decision-making, and 3) action (i.e., skill,the quality of the technical aspects of the operation). Datafrom imaging reports (operative and postoperative), repar-ative operations, and videotapes were analyzed and com-pared with the original operative reports to determine thecause of the injury and the working assumptions of thesurgeon.
The following criteria were employed when categorizingthe errors. We considered misperception to have occurred ininstances where the data showed that 1) the surgeon hadseen and deliberately cut a duct that he or she thought at thatmoment was a different duct (e.g., the surgeon cut the CBDthinking it was the cystic duct), or 2) the surgeon injured anunseen duct while performing a dissection that he or shebelieved was a safe distance from the duct (e.g., a scenariocharacteristic of class II injuries). The error was consideredto represent faulty decision-making or a knowledge error ifthe data indicated that 1) the surgeon had departed from the
orthodox operative strategy for performing a laparoscopiccholecystomy, or 2) had performed the operation in a settingwhere laparoscopic cholecystectomy was inappropriate. Weconsidered that the fault was at the action or skill level whenthere was evidence that the dissection was performed in aclumsy way; when an identified duct being cleared of con-nective tissue was accidentally cut or cauterized. In thediscussion section we have interpreted the findings accord-ing to accepted principles of cognitive psychology andhuman error. Although some of these ideas may be new tosurgeons, we are unable to argue their validity within thecontext of this paper. Instead, we have cited representativeliterature that will allow the reader to determine for himselfor herself the strength of their foundations.
Mechanism of Injury and InjuryClassification
The patients were grouped into four classes (Fig. 1) basedon the mechanism and anatomy of the injury (Tables 1 and2). Class I injuries (7% of cases) involved an incision (anincomplete transection) of the CBD with no loss of duct.Class I injuries occurred in two ways: either 1) the CBD wasmistaken for the cystic duct (72%), but the mistake wasrecognized, usually by operative cholangiography, beforethe duct was completely transected; or 2) an incision madein the cystic duct for the cholangiogram catheter was unin-tentionally extended into the CBD (28%). The right hepaticartery was injured in one (5%) of these cases.
Class II injuries (22% of cases) consisted of lateral dam-age to the CHD that produced stricture and/or fistula for-mation. These injuries usually involved the placement of
Figure 1. Classification of laparoscopic bile duct injuries. The mech-anism of the injury is in the text and Table 1. Class III injuries aresubdivided according to the location of the proximal line of transection.
Vol. 237 No. 4 Causes and Prevention of Laparoscopic Bile Duct Injuries 461
clips on the duct in conjunction with cautery damage duringattempts to control bleeding (23%) or as a result of poorexposure (68%). Class II injuries never completely transectedor occluded the CHD; they involved severe lateral damageleading to stricture formation (with or without a bile leak). Intwo patients the right hepatic artery originated from the supe-rior mesenteric artery, and the anomaly probably contributed tothe injury. In six cases (9%) strictures followed CBD explo-ration with T-tube placement into normal-sized ducts. Theright hepatic artery was injured in 18% of these cases.
Class III injuries, the most common (61% of cases),involved transection of the CBD and excision o