Educational Impact of Artificial Intelligence‐Navigation Surgery on Anatomical Landmark Recognition in Medical Students

BackgroundAccording to the National Clinical Database of Japan, the incidence of bile duct injury (BDI) during laparoscopic cholecystectomy has hovered around 0.4% for the last 10 years and has not declined. On the other hand, it has been found that about 60% of BDI occurrences are due to misidentifying anatomical landmarks. However, the authors developed an artificial intelligence (AI) system that gave intraoperative data to recognize the extrahepatic bile duct (EHBD), cystic duct (CD), inferior border of liver S4 (S4), and Rouviere sulcus (RS). The purpose of this research was to evaluate how the AI system affects landmark identification.MethodsWe prepared a 20-s intraoperative video before the serosal incision of Calot’s triangle dissection and created a short video with landmarks overwritten by AI. The landmarks were defined as landmark (LM)-EHBD, LM-CD, LM-RS, and LM-S4. Four beginners and four experts were recruited as subjects. After viewing a 20-s intraoperative video, subjects annotated the LM-EHBD and LM-CD. Then, a short video is shown with the AI overwriting landmark instructions; if there is a change in each perspective, the annotation is changed. The subjects answered a three-point scale questionnaire to clarify whether the AI teaching data advanced their confidence in verifying the LM-RS and LM-S4. Four external evaluation committee members investigated the clinical importance.ResultsIn 43 of 160 (26.9%) images, the subjects transformed their annotations. Annotation changes were primarily observed in the gallbladder line of the LM-EHBD and LM-CD, and 70% of these shifts were considered safer changes. The AI-based teaching data encouraged both beginners and experts to affirm the LM-RS and LM-S4.ConclusionThe AI system provided significant awareness to beginners and experts and prompted them to identify anatomical landmarks linked to reducing BDI.

The objective of this report was to study the sensitivity of indicators used for predicting bile duct stones and their endoscopic removal before laparoscopic cholecystectomy. A retrospective study was conducted on 104 patients who successfully underwent endoscopic retrograde cholangiopancreatogram (ERCP) before laparoscopic cholecystectomy at Riyadh Medical Complex between 1992 and 1994 (1412H-1414H). Six indicatorsâjaundice, biliary pancreatitis, stones in bile duct on sonography, dilated bile duct (>7 mm) on ultrasonography, dilated bile duct with deranged liver function test, and deranged liver function test without jaundiceâwere used for suspecting choledocholithiasis and endoscopic removal before laparoscopic cholecystectomy. Ultrasound correctly predicted bile duct stone in 75%, followed by dilated bile duct with deranged liver function test (46%). Clinical jaundice and biliary pancreatitis were equally sensitive indicators (42% each). Sensitivity of only dilated bile duct on ultrasonography in predicting duct stone was 36%. Deranged liver function without jaundice was the least sensitive (22%) of the predictors. Overall, these indicators correctly diagnosed bile duct stones in 34% of patients. Until laparoscopic exploration of bile duct or a noninvasive technique, such as magnetic resonance cholangiopancreatogram (MRCP), is widely available, these predictors will help in selecting patients with bile duct stones for preoperative removal. Other workers have suggested combining these indicators to improve the predictive value.

The incidence of aberrant bile duct injury associated with laparoscopic cholecystectomy (LC) has not yet been adequately examined. This study aimed to clarify the types of normal cystic ducts and the incidence of aberrant extrahepatic bile ducts, and to search for a method of avoiding injuries during LC. Aberrant hepatic ducts were retrospectively categorized into five types according to the pattern of the cystic ducts and the accessory hepatic ducts by preoperative endoscopic retrograde cholangiography or multidetector three-dimensional computed tomography using drip infusion cholangiography. The aberrant bile ducts were classified as type A (merging at the right side of the common bile duct), type B (merging at the anterior side), or type C (merging at the posterior left side). The intrahepatic bile ducts and cystic duct were clearly shown for 1,044 of the 1,278 patients who underwent LC. Secondary branches of aberrant cystic ducts were observed in 37 cases (3.5%), and accessory hepatic ducts were observed in 30 cases (2.9%). A comparison of the difficulties encountered with LC for each type based on the merging patterns of cystic ducts showed that type C needed a much longer operation time for LC than the other types. A preoperative evaluation of the bile duct tract and the accessory hepatic duct before LC is important. Patients with a cystic duct merging normally into the posterior left side of the common hepatic duct (type C) experienced difficulty when undergoing LC. The authors have safely performed LC with the use of an endoscopic nasobiliary drainage tube in type D cases (cystic duct merging with the right hepatic duct), in type IV cases (cystic duct merging with an accessory hepatic duct).

Bile duct injury can occur more frequently during laparoscopic cholecystectomy than in open cholecystectomy. Three cases of common bile or hepatic duct injuries occurred in a series of eighty laparoscopic cholecystectomies; In case 1, the common bile duct was misidentified as the cystic duct. In case 2, bile peritonitis occurred on the fourth postoperative day caused by necrosis of the common hepatic duct involving the cautery surrounding it. In case 3, a bile leak occurred due to an incision at the confluence of the cystic and common duct. Dissection of the cystic duct at the infundibulum of the gallbladder, blunt dissection of the Calot's triangle, the handling of clips with special attention for safety were thought to be necessary in order to lower the risk of bile duct injury. Preoperative endoscopic retrograde cholangiography (ERCP) is recommended to avoid bile duct injury.

Laparoscopic cholecystectomy was introduced into wide practice about 1990, with demonstrated benefit to patients. However, it was associated with a sharp increase in major bile duct injuries. Biliary injuries are morbid, costly, and the source of litigation. Although not usually due to negligence, they are iatrogenic and detract from the value of laparoscopic cholecystectomy. Most major bile duct injuries are due to misidentification. In the “classical injury,” the common bile duct is thought to be the cystic duct and is divided. Aberrant hepatic ducts may also be mistakenly identified as the cystic duct or cystic artery. The Critical View of Safety (CVS) is a method of target identification, the targets being the cystic duct and the cystic artery. Today, CVS is taught and used widely. It is accepted as a good means of identification of the cystic structures and its use is within the standard of care. The purpose of this surgical perspective is to examine whether CVS has reached the status of being the only acceptable method for identification of structures in laparoscopic cholecystectomy. HISTORY OF THE CRITICAL VIEW OF SAFETY The term “Critical View of Safety” was introduced in an analytical review written in response to the sudden increase in biliary injury associated with laparoscopic cholecystectomy.1 CVS is a re-working of a method of secure identification in open cholecystectomy in which the cystic duct and artery are putatively identified, after which the gallbladder is taken off the cystic plate so that the gallbladder is attached only by the 2 cystic structures.2 Only then is secure target identification achieved. In laparoscopic surgery, complete separation of the gallbladder from the cystic plate makes clipping of the cystic structures difficult, so this step was modified to require only that the lower part of the gallbladder (about one-third) be separated from the cystic plate. The other requirements, that is, that the hepatocystic triangle be cleared of fat and fibrous tissue and that 2 and only 2 structures remain attached to the gallbladder, are the same as in the open technique. Intraoperatively, CVS should be confirmed in a “time-out” in which the 3 elements of CVS are demonstrated. After the introduction of CVS in1995, operative notes were studied in an attempt to determine if CVS was used in procedures in which biliary injury had occurred.3 It was found that the method of target identification that was failing was not CVS, but the infundibular technique in which the cystic duct is identified by exposing the funnel shape where the infundibulum of the gallbladder joins the cystic duct. Inflammatory fusion and contraction may cause juxtaposition or adherence of the common hepatic duct to the side of the gallbladder. When the infundibular technique of identification is used under these circumstances, a compelling visual deception may result that the common bile duct is the cystic duct.3 CVS is less susceptible to this deception because more exposure of structures is needed to achieve CVS. Either the CVS is attained, by which time the anatomic situation is usually clarified, or operative conditions such as severe acute or chronic inflammation prevent attainment of the CVS. In the latter case, when the CVS cannot be reached, 1 of several important “bail-out” strategies such as subtotal fenestrating cholecystectomy4 can be employed, thus avoiding bile duct injury. Of course, the CVS should not be seen in isolation, but as an element of an overall schema of a “Culture of Safety in Cholecystectomy” in which other elements such as good bail-out techniques, good access techniques, and other elements of safety are also employed. EFFECTIVENESS OF THE CRITICAL VIEW OF SAFETY There are 2 principal lines of evidence that the CVS is an effective method of target identification. First, there are several reports containing several thousand patients in which CVS was used for target identification without a biliary injury due to misidentification,5,6 whereas, based on an incidence of biliary injury of 3 to 4/1000 cases, about 20 biliary injuries would be expected. Secondly, in studies that have examined the mechanisms of major biliary injury, CVS has rarely been described as the method of target identification.7,8 Taken as a group, these studies are highly supportive of the value of CVS, but from the perspective of evidence-based medicine, they are at a low level of evidence. So, why after 25 years has there not been a randomized trial that compares methods of target identification? The answer lies in the fact that although many major biliary injuries still occur, that is, 2000 to 3000 per year in the USA, the event rate is only about 3 per 1000 cholecystectomies (up from about 1 per 1000 in the era of open cholecystectomy). A randomized trial cannot practically be performed because the event rate is so low that about 4500 patients per arm would be required. Despite the low event rate, biliary injuries are not uncommon because of the huge number of cholecystectomies performed annually—about 800,000 in the USA. Thus, biliary injury has aspects of a rare disease and a common disease. There are also important corollaries. Case series of laparoscopic cholecystectomies are almost always too small to provide insights into the causes of biliary injury. Population studies of thousands of patients are required to have enough events to gain meaningful insights. That is why going back almost 100 years,9 much of what is known about biliary injury has been gleaned not from case series of cholecystectomies, but from case series of the injuries themselves. WHAT CONSTITUTES STANDARD OF CARE? “Standard of care” is the legal term for the duty owed by one person to another and applies to both nonmedical and medical situations (such as driving a car). It is the amount of care that a reasonable person would take to prevent injury to another person. In the medical-legal context, a doctor must use the amount of skill, learning, and care ordinarily used by members of his/her profession in similar circumstances. Whether a given treatment or procedure is acceptably within the standard of care depends on whether it falls within the norms of practice, which are established by professional authorities in writings and recorded electronic communications. In recent years, the evidence presented in these communications has been graded from 1 to 5, with randomized trials being at a very high level, whereas case series and expert opinion are considered weaker evidences. Often several ways of diagnosis or treatment fall within the standard of care. Consensus conferences which weigh the available evidence regarding a type of care may sometimes conclude that there is high level evidence that one particular type of care is superior to all others. That type of conclusion, if based on high levels of evidence, could establish that failure to use a specific type of care in a particular situation will most likely be below the standard. An obvious example would be the failure to use antibiotics in an acute bacterial infection such as cellulitis. Finally, in determining standard of care, an important criterion is whether a type of care is in broad use by qualified surgeons. If it is, even by a moderate percentage of surgeons, then there is a strong argument that it falls within the standard of care. IS THE CRITICAL VIEW OF SAFETY THE ONLY ACCEPTABLE MEANS OF DUCTAL IDENTIFICATION DURING LAPAROSCOPIC CHOLECYSTECTOMY? Critical View of Safety, routine cholangiography, the infundibular technique, visualization of the common bile duct and common hepatic duct, and top-down cholecystectomy are some methods that have been advocated for target identification in cholecystectomy. CVS is not the only method within the standard of care for the following reasons. Textbooks of surgery may10 or may not11 recommend CVS as the method of target identification. The evidence that CVS is superior to all other methods is level 4, that is, case series. No consensus conference has published a guideline that CVS is the only effective method of target identification. Many surgeons in current practice use and are confident in other methods.12 The fact that some experts believe that CVS is the preferred method of target identification in laparoscopic cholecystectomy is insufficient alone to establish it as the only method within the standard of care. Stated otherwise, at this time, CVS is not the only method of ductal identification within the standard of care. PROBLEMS WITH CVS Dissemination of new information is a difficult problem in surgery. Even after more than 20 years, surgeons often have a poor understanding of the criteria for CVS, and may confuse CVS with the infundibular technique.12,13 Reluctance to adopt new techniques or methods can also be a challenge. In the case of CVS, this is compounded by the low event rate of biliary injury, which makes an error trap like the infundibular technique even harder to overcome. If it fails only 1 in 300 times, then it works 299 out of 300 times and there is a huge reservoir of confidence in it.13 Also, the infundibular method is easier and takes less dissection than CVS. Attainment of the CVS is not usually recorded or documented photographically, and although the dictated operative note may state that the CVS was achieved, recent evidence suggests this is frequently not the case.7 FUTURE OF CVS Critical View of Safety is part of the Culture of Safety In Cholecystectomy (COSIC) and this problem has been taken up by SAGES in a novel effort called “Safe Cholecystectomy” (www.sages.org/safe-cholecystectomy-program) The SAGES Safe Cholecystectomy program aims to better disseminate understanding and use of CVS and other strategies for prevention of biliary injury such as use of intraoperative imaging and approaches to the difficult gallbladder that include proper bail-out techniques.4 A multisociety consensus development conference is planned in 2017 on the subject of bile duct injury to study and promote safety in cholecystectomy. The role and application of CVS and other strategies for prevention of biliary injury will be critically examined in that forum. An effective and easy method of photodocumentation of CVS is now available for surgeons who wish to record CVS visually.14 For those who wish to record it in operative notes, it is important to know that CVS cannot be said to have been achieved without attainment of all 3 elements of this method of target identification. We dictate these 3 elements into operative notes and recommend it as an excellent practice. ACKNOWLEDGMENT The authors thank Ms Christine A. Vaporean of the law firm of Brown and James, Saint Louis, Missouri, for helpful discussions and suggestions.

ObjectivesTo develop and evaluate a deep learning model for segmentation of the coronary artery vessels and coronary plaques in coronary computed tomography angiography (CCTA).Materials and methodsCCTA image data from the Swedish CardioPulmonary BioImage Study (SCAPIS) was used for model development (n = 463 subjects) and testing (n = 123) and for an interobserver study (n = 65). A dataset from Linköping University Hospital (n = 28) was used for external validation. The model’s ability to detect coronary artery disease (CAD) was tested in a separate SCAPIS dataset (n = 684). A deep ensemble (k = 6) of a customized 3D vision transformer model was used for voxelwise classification. The Dice coefficient, the average surface distance, Pearson’s correlation coefficient, analysis of segmented volumes by intraclass correlation coefficient (ICC), and agreement (sensitivity and specificity) were used to analyze model performance.ResultsPlaqueViT segmented coronary plaques with a Dice coefficient = 0.55, an average surface distance = 0.98 mm and ICC = 0.93 versus an expert reader. In the interobserver study, PlaqueViT performed as well as the expert reader (Dice coefficient = 0.51 and 0.50, average surface distance = 1.31 and 1.15 mm, ICC = 0.97 and 0.98, respectively). PlaqueViT achieved 88% agreement (sensitivity 97%, specificity 76%) in detecting any coronary plaque in the test dataset (n = 123) and 89% agreement (sensitivity 95%, specificity 83%) in the CAD detection dataset (n = 684).ConclusionWe developed a deep learning model for fully automatic plaque detection and segmentation that identifies and delineates coronary plaques and the arterial lumen with similar performance as an experienced reader.Key PointsQuestionA tool for fully automatic and voxelwise segmentation of coronary plaques in coronary CTA (CCTA) is important for both clinical and research usage of the CCTA examination.FindingsSegmentation of coronary artery plaques by PlaqueViT was comparable to an expert reader’s performance.Clinical relevanceThis novel, fully automatic deep learning model for voxelwise segmentation of coronary plaques in CCTA is highly relevant for large population studies such as the Swedish CardioPulmonary BioImage Study.Graphical

Objective To summarize our clinical experience and management of an anomalous proximal bile duct joining the cystic duct in laparoscopic cholecystectomy (LC). Methods A retrospective study was conducted on 8 patients who had an anomalous right anterior bile duct joining the cystic duct who were treated at the Hunan Provincial People's Hospital from March 2003 to January 2019. Results All the 8 patients were diagnosed to have gallstones cholecystitis on preoperative CT, MRI and abdominal ultrasound. There were no suggestions of an anomalous bile duct. A total of 6 patients underwent reoperation after LC due to abdominal pain and biliary peritonitis. These 6 patients were treated with drainage and T-tube insertion. In the other 2 patients, the anomalous bile duct opening which joined the cystic duct were detected during LC. There was one patient converted to open laparotomy with preservation of the cystic duct and underwent common bile duct T-tube drainage. The other patients continued with laparoscopic surgery. The cystic duct was partially resected with removal of gallbladder, followed by common bile duct drainage. The average follow-up period was 3.4 years and the results were satisfactory. Conclusions Biliary duct anomaly is the main cause of iatrogenic proximal bile duct injury during laparoscopic cholecystectomy. It is not uncommon to have the anomaly of insertion of right anterior segmental bile duct to the cystic duct. To avoid iatrogenic biliary tract injury, careful preoperative study of X-ray films, accurate identification of the intraoperative gallbladder triangle anatomical structures. Strict adherence to carry out the three-word procedure of discrimination, cut, identify will help to reduce the incidence of biliary tract complications in laparoscopic cholecystectomy. Key words: Cholecystectomy; Biliary duct injury; Bile duct variation; Right lower anterior lobe; Repair strategy

Acquired abnormalities of the biliary tract from chronic gallstone disease

Cardio-pulmonary substructure segmentation of radiotherapy computed tomography images using convolutional neural networks for clinical outcomes analysis

BackgroundThe 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.MethodsAn 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.ResultsThe 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.ConclusionsIntraoperative 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.

Background: While laparoscopic cholecystectomy is widely accepted for therapy of cholecystolithiasis, controversy still exists concerning the routine use of intra-operative cholangiography (IOC) during laparoscopic cholecystectomy (LC) and its role in management of common bile duct stones at the same procedure whether it is discovered accidentally or expected as a single stage procedure if respective experience is available.Methods: During laparoscopic cholecystectomy a cholangiography via the cystic duct is routinely performed.If bile duct stones are detected they are retrieved via the cystic duct or via incision of the common bile duct by insertion of a Fogarty catheter or Dormia basket.Exclusion criteria against simultaneous laparoscopic management include suspicious of malignancy, severe pancreatitis or cholangitis.Results: From July 2005 to June 2007, 172 patients primarily underwent laparoscopic cholecystectomy at Landeskrankenhaus Bregenz (170 cases) & at Ain Shams Specialized Hospital (2 cases), IOC was successful in 157 (91.2%).Bile duct stones were found in 26 patients (15.1%), dilated ducts without stones in 6 patients (3.4%), and anatomic variations in 3 patients (1.7%).Retrieval was performed via cystic duct and common bile duct in 15 and 11 cases respectively with complete removal.There were 2 (1.1%) minor injuries of the bile duct, which were identified with IOC and repaired at the time of cholecystectomy without any consequences for the patients, while in 3 patients (1.7%) Cholecystography was done for difficult identification of cystic duct and acute inflamed gall bladder.Conclusion: Routine intra-operative cholangiography is feasible, provides valuable information about the anatomy of the biliary tract and might aid in the prevention of bile duct injuries, thereby improving the safety of laparoscopic cholecystectomy.Also, when correct indications and surgical expertise are available, simultaneous laparoscopic management of common bile duct stones represent a safe and minimally invasive alternative to a two stage procedure approach.

Background: While laparoscopic cholecystectomy is widely accepted for therapy of cholecystolithiasis, controversy still exists concerning the routine use of intra-operative cholangiography (IOC) during laparoscopic cholecystectomy (LC) and its role in management of common bile duct stones at the same procedure whether it is discovered accidentally or expected as a single stage procedure if respective experience is available. Methods: During laparoscopic cholecystectomy a cholangiography via the cystic duct is routinely performed. If bile duct stones are detected they are retrieved via the cystic duct or via incision of the common bile duct by insertion of a Fogarty catheter or Dormia basket. Exclusion criteria against simultaneous laparoscopic management include suspicious of malignancy, severe pancreatitis or cholangitis. Results: From July 2005 to June 2007, 172 patients primarily underwent laparoscopic cholecystectomy at Landeskrankenhaus Bregenz (170 cases) & at Ain Shams Specialized Hospital (2 cases), IOC was successful in 157 (91.2%). Bile duct stones were found in 26 patients (15.1%), dilated ducts without stones in 6 patients (3.4%), and anatomic variations in 3 patients (1.7%). Retrieval was performed via cystic duct and common bile duct in 15 and 11 cases respectively with complete removal. There were 2 (1.1%) minor injuries of the bile duct, which were identified with IOC and repaired at the time of cholecystectomy without any consequences for the patients, while in 3 patients (1.7%) Cholecystography was done for difficult identification of cystic duct and acute inflamed gall bladder. Conclusion: Routine intra-operative cholangiography is feasible, provides valuable information about the anatomy of the biliary tract and might aid in the prevention of bile duct injuries, thereby improving the safety of laparoscopic cholecystectomy. Also, when correct indications and surgical expertise are available, simultaneous laparoscopic management of common bile duct stones represent a safe and minimally invasive alternative to a two stage procedure approach.

Objective To investigate the clinical effect of laparoscopic reverse papillary intubation through cystic duct and laparoscope combined with duodenoscope in the treatment of cholecystolithiasis and thining choledocholithiasis. Methods The retrospective cohort study was adopted. The clinical data of 192 patients with cholecystolithiasis and thining choledocholithiasis who were admitted to Chengdu Second People's Hospital between May 2012 to August 2015 were collected. The 96 patients who underwent laparoscopic reverse papillary intubation through cystic duct were allocated into the case group, and the other 96 who received surgery by laparoscope combined with duodenoscope were allocated into the control group. All the patients underwent laparoscopic cholecystectomy (LC) according to routine approaches. The 96 patients in the case group received the placement of 4 Fr ureter catheter via cystic duct and placement of common bile duct inserted through the duodenal papilla under laparoscope, and then the duodenal papilla was resected using needle knife along the ureter catheter and stones were removed by basket lithotriptor and ball lithotriptor. The 96 patients in the control group received the intubation using the bow knife with zebra guidewire, and stones were removed by basket lithotriptor and ball lithotriptor. During the operations, it was observed whether there were residual stones by nasobiliary radiograph. The comparison was made between the 2 groups concerning (1) surgical situation: intubation and operation time. (2) Postoperative alanine transaminase (ALT), postoperative aspartate transaminase (AST), postoperative total bilirubin (TBil), postoperative blood amylase, postoperative lipase, complications and extubation time. (3) Situation of follow-up: follow-up was done by outpatient examination or telephone interview up to November 2015. The stones recurrence was detected by retrograde cholangiography through nasal bile duct, magnetic resonance cholangiopancreatography (MRCP) or ultrasonic examination. Measurement data with normal distribution were represented as ±s. Comparison between groups was done by the t test. Count data were analyzed by the chi-square test. Results (1) Surgical situation: 2 groups both underwent successful LC. Ureteral catheter in the case group was successfully imbedded through cystic duct, including 8 patients with being difficult to intubate. Five patients in the control group were failed in endoscopic sphincterotomy (EST) due to periamullary diverticula or other causes, and then EST was performed again by the duodenal papilla through ureteral catheter which was intubated through cystic duct. Operation time of the case group and control group was (89±17)minutes and (105±26)minutes, respectively, with a statistically significant difference between the 2 groups (t=5.05, P 0.05). Postoperative blood amylase and lipase of the case group and control group were (151±41)U/L, (198±72)U/L and (395±142)U/L, (549±217)U/L, respectively, showing statistically significant differences (t=16.18, 15.05, P<0.05). No pancreatitis was found in the case group while 6 patients in the control group complicated with mild pancreatitis were improved by symptomatic treatment of fasting, somatostatin administration and acid suppression, with no severe pancreatitis. No complications such as intestinal perforation, bile duct perforation and massive hemorrhage were detected in both groups after operation. No death occurred. The nasal bile duct in the patients without pancreatitis was removed at postoperative day 3. The nasal bile duct in the patients with pancreatitis was removed after the remission of abdominal pain and diet intake. In the case group, it was difficult to remove the nasal bile duct of 1 patient. Nasal bile duct radiograph showed that the bending section of nasal bile duct was mistakenly sutured by the absorbable thread at the lower margin of incision of junction of cystic ducts, and yet there was unobstructed biliary drainage. The nasal bile duct was removed and the patient was discharged from hospital at postoperative day 19. The abdominal drainage tubes were removed at postoperative day 3 to 5 in both groups. (3) Of 192 patients, 151 were followed up for a median time of 10 months (range, 3-12 months). Patients had good recovery without recurrence of abdominal pain, jaundice and stones. Conclusion Laparoscopic reverse papillary intubation through cystic duct for the treatment of cholecystolithiasis and thining choledocholithiasis is safe and feasible, and it can also reduce incidence of pancreatitis after nasobiliary drainage. Key words: Cholelithiasis; Choledocholithiasis; Laparoscopy; Endoscopy; Nasobiliary drainage

Introduction: Patients with cholecystitis often present with abdominal pain, nausea and vomiting. The treatment for cholecystitis often is a cholecystectomy. Pathogenesis of cholecystitis entails blockage of the cystic duct resulting in inflammation up-stream from the site of obstruction. Stones are often the cause of this obstruction, and can often enter the bile duct, causing bile duct obstruction. Cystic duct often merges with the common hepatic duct in the extrahepatic but non-pancreatic portion. Imaging such as Ultrasound and MRI in such cases would reveal a filling defect within the bile duct. We present a case where the cystic duct opened directly at the ampulla. Case Description/Methods: A 68 year-old female presented with abdominal pain, nausea and vomiting. Laboratory testing revealed normal AST, ALT and Alkaline phosphatase. Bilirubin was elevated. Ultrasound imaging revealed findings of cholecystitis. A magnetic resonance cholangiopancreatography was performed (Figure a) that revealed a normal common bile duct (CBD), and a dilated cystic duct with a filling defect consistent with a stone. Interestingly, it revealed cystic duct insertion close to the ampulla. During laparoscopic cholecystectomy, an intraoperative cholangiogram (Figure b) with contrast injection into the cystic duct revealed multiple filling defects in the cystic duct with contrast draining into the small bowel through the papilla. ERCP with cholangioscopy confirmed the cystic duct opening into the ampulla. Treatment entailed ERCP with cholangioscopy and lithotripsy. Discussion: Recognizing anatomical variants and considering these in the differential can help in understanding unusual clinical presentations of biliary pathologies.Figure 1.: a: MRCP images showing stones (green arrow) in cystic duct with cystic duct opening at the ampulla; b: Intraoperative cholangiogram confirming cystic duct stones with cystic duct opening at the ampulla.

The risk of damage to the bile duct and structures in the hilum of the liver is significant when Calot's triangle cannot be safely dissected during laparoscopic cholecystectomy, and conversion to an open procedure often is performed. This is more common during emergency surgery, but may not render the procedure any easier. Traditionally, open subtotal cholecystectomy was performed, but with the advent of laparoscopic surgery, this has fallen from favor. The authors report their experience using laparoscopic subtotal cholecystectomy to avoid bile duct injury and conversion in difficult cases. Laparoscopic subtotal cholecystectomy, performed when the cystic duct cannot be identified safely, consists of resecting the anterior wall of the gallbladder, removing all stones, and placing a large drain into Hartmann's pouch. The notes for all patients who underwent a laparoscopic subtotal cholecystectomy between 1 September 2001 and 31 December 2004 were retrospectively analyzed. Subtotal cholecystectomy was performed in 26 cases including 13 emergency and 13 elective procedures. The median age of the patients (15 women and 11 men) was 68 years (range, 36-86 years). The indications were severe fibrosis in 16 cases, inflammatory mass or empyema in 8 cases, and gangrenous gallbladder or perforation in 2 cases. The median postoperative inpatient stay was 5 days (range, 2-26 days). Five patients underwent postoperative endoscopic retrograde cholangiopancreatography: four for persistent biliary leak and one for a retained common bile duct stone. One patient required laparotomy for subphrenic abscess, and one patient (American Society of Anesthesiology [ASA] grade 4, presenting with biliary peritonitis) died 2 days postoperatively. One patient required a subsequent completion laparoscopic cholecystectomy for a retained gallstone. One patient had a chest infection, and two patients experienced port-site hernias. Laparoscopic subtotal cholecystectomy is a viable procedure during cholecystectomy in which Calot's triangle cannot be dissected. It averts the need for a laparotomy.