Increasing use of intraoperative cholangiogram in Australia: is it evidence-based?

Using neural networks to autonomously assess adequacy in intraoperative cholangiograms

BACKGROUND

Intraoperative cholangiography (IOC) is a contrast-enhanced X-ray acquired during laparoscopic cholecystectomy. IOC images the biliary tree whereby filling defects, anatomical anomalies and duct injuries can be identified. In Australia, IOC are performed in over 81% of cholecystectomies compared with 20 to 30% internationally (Welfare AIoHa in Australian Atlas of Healthcare Variation, 2017). In this study, we aim to train artificial intelligence (AI) algorithms to interpret anatomy and recognise abnormalities in IOC images. This has potential utility in (a) intraoperative safety mechanisms to limit the risk of missed ductal injury or stone, (b) surgical training and coaching, and (c) auditing of cholangiogram quality.

METHODOLOGY

Semantic segmentation masks were applied to a dataset of 1000 cholangiograms with 10 classes. Classes corresponded to anatomy, filling defects and the cholangiogram catheter instrument. Segmentation masks were applied by a surgical trainee and reviewed by a radiologist. Two convolutional neural networks (CNNs), DeeplabV3+ and U-Net, were trained and validated using 900 (90%) labelled frames. Testing was conducted on 100 (10%) hold-out frames. CNN generated segmentation class masks were compared with ground truth segmentation masks to evaluate performance according to a pixel-wise comparison.

RESULTS

The trained CNNs recognised all classes.. U-Net and DeeplabV3+ achieved a mean F1 of 0.64 and 0.70 respectively in class segmentation, excluding the background class. The presence of individual classes was correctly recognised in over 80% of cases. Given the limited local dataset, these results provide proof of concept in the development of an accurate and clinically useful tool to aid in the interpretation and quality control of intraoperative cholangiograms.

CONCLUSION

Our results demonstrate that a CNN can be trained to identify anatomical structures in IOC images. Future performance can be improved with the use of larger, more diverse training datasets. Implementation of this technology may provide cholangiogram quality control and improve intraoperative detection of ductal injuries or ductal injuries.

Is Routine Intraoperative Cholangiogram Necessary in Patients With Mild Acute Biliary Pancreatitis Undergoing Index Admission Cholecystectomy?

Background: There is controversy about whether intraoperative cholangiogram (IOC) should be performed routinely during laparoscopic cholecystectomy for patients with acute biliary pancreatitis, given significant false positive and negative rates and increased resource utilization. The aim of this study was to clarify the role of IOC in cases of mild biliary pancreatitis in patients undergoing index admission cholecystectomy, its impact on patient outcomes, and the impact of blood tests, imaging, and preoperative intervention on the detection of choledocholithiasis.Methods: A retrospective review of all patients presenting with acute mild biliary pancreatitis between January 2006 and December 2019 was conducted. Data collected included patient demographics, serum chemistry, IOC, and Endoscopic Retrograde Cholangiopancreatography (ERCP) findings, imaging findings, length of stay, operative length, and long-term follow-up outcomes.Results: 284 patients met the inclusion criteria for the study. The overall false positive IOC rate was 7.4%. Worsening bilirubin trend was a positive predictive value (PPV) for positive IOC and ERCP outcomes with a relative risk of 2.93 (P < .01) and 2.32 (P = .013), respectively. Improving preoperative bilirubin trend had a significant negative predictive value in IOC with a relative risk of .59 (P = .02). Positive IOC was shown to significantly increase operative length with a relative risk of 2.03 (P < .001).Discussion: A rising preoperative bilirubin is a predictor of a positive IOC and patients with normalizing bilirubin levels or a preoperative ERCP are less likely to have choledocholithiasis. These features may be used to select patients that would benefit from an IOC for index admission cholecystectomy.

Prophylactic cholecystectomy offers best outcomes following ERCP clearance of common bile duct stones: a meta-analysis

BACKGROUND

Symptomatic calculus biliary disease is common with associated morbidity and occasional mortality, further confounded when there is concomitant common bile duct (CBD) stones. Choledocholithiasis and clearance of the duct reduces recurrent cholangitis, but the question is whether after clearance of the CBD if there is a need to perform a cholecystectomy. This meta-analysis evaluated outcomes in patients undergoing ERCP with or without sphincterotomy to determine if cholecystectomy post-ERCP clearance offers optimal outcomes over a wait-and-see approach.

METHODS

A Prospero registered meta-analysis of the literature using PRISMA guidelines incorporating articles related to ERCP, choledocholithiasis, cholangitis and cholecystectomy was undertaken for papers published between 1st January 1991 and 31st May 2021. Existing research that demonstrates outcomes of ERCP with no cholecystectomy versus ERCP and cholecystectomy was reviewed to determine the related key events, complications and mortality of leaving the gallbladder in situ and removing it. Odds ratios (OR) were calculated using Review Manager Version 5.4 and meta-analyses performed using OR using fixed-effect (or random-effect) models, depending on the heterogeneity of studies.

RESULTS

13 studies (n = 2598), published between 2002 and 2019, were included in this meta-analysis, 6 retrospective, 2 propensity score-matched retrospective studies, 3 prospective studies and 2 randomised control trials from a total of 11 countries. There were 1433 in the no cholecystectomy cohort (55.2%) and 1165 in the prophylactic cholecystectomy (44.8%) cohort. Cholecystectomy resulted in a decreased risk of cholecystitis (OR = 0.15; CI 0.07-0.36; p < 0.0001), cholangitis (OR = 0.51; CI 0.26-1.00; p = 0.05) and mortality (OR = 0.38; CI 0.16-0.9; p = 0.03). In addition, prophylactic cholecystectomy resulted in a significant reduction in biliary events, biliary pain and pancreatitis.

CONCLUSIONS

In patients undergoing CBD clearance, consideration should be given to performing prophylactic cholecystectomy to optimise outcomes.

Incidental Intraoperatively Detected Choledocholithiasis: A General Surgeon's Approach to Management

Background Up to 15% of patients with cholelithiasis have choledocholithiasis, with almost 10% not detected pre-operatively. Our study aims to quantify the prevalence of incidental choledocholithiasis during routine intra-operative cholangiogram (IOC), identify the best management pathway, and identify reliable pre-operative factors to predict choledocholithiasis. Methods We conducted a single-centre, retrospective cohort study at St John of God Midland Hospital in Western Australia, Perth, on 880 consecutive patients who underwent cholecystectomies performed by 15 surgeons between January 2, 2020, and December 30, 2021.  Results The overall choledocholithiasis rates were 10.6% (93), with 4.0% (35) diagnosed pre-operatively and 6.6% (58) diagnosed during IOC. In all, 50% of incidental choledocholithiasis during IOC were managed with hyoscine butylbromide, with a 55.2% success rate; 22.4% of patients received octreotide, with a 61.5% success rate; and 8.6% of patients underwent trans-cystic bile duct exploration (TCBE) and 8.6% underwent postoperative endoscopic retrograde cholangiopancreatography (ERCP), both with 100% success rates. Choledocholithiasis most commonly presents with gallstone pancreatitis, with a median aspartate aminotransferase (AST) level 7.2 times and alanine transaminase (ALT) level 7.8 times higher than those of patients without choledocholithiasis. Magnetic resonance cholangiopancreatography (MRCP) was the most sensitive in identifying choledocholithiasis with a 66.7% pickup rate. The median common bile duct (CBD) diameter on ultrasound was 8 mm, computerised tomography scans were 11 mm, and MRCP was 9 mm. Conclusion One in 10 cholecystectomies will be complicated with choledocholithiasis, and over half will be incidentally diagnosed during routine IOC. We propose IOC in all cases and hyoscine butylbromide, octreotide, and saline flushes as first-line treatment; if unsuccessful, TCBE is performed. Gallstone pancreatitis, markedly elevated AST/ALT, and imaging showing CBD ≥8 mm may serve as early predictors of choledocholithiasis.

Is the use of a routine intraoperative cholangiogram necessary in laparoscopic cholecystectomy?

INTRODUCTION

Although laparoscopic cholecystectomy (LC) has been standard of care for symptomatic gallstone disease for almost 30 years, the use of routine intraoperative cholangiogram (IOC) remains controversial. There are marked variations in the use IOC during LC internationally. Debate has continued about its benefit, in part because of inconsistent benefit, time, and resources required to complete IOC. This literature review is presented as a debate to outline the arguments in favour of and against routine IOC in laparoscopic cholecystectomy.

METHODS

A standard literature review of PubMed, Medline, OVID, EMBASE, CINHIL and Web of Science was performed, specifically for literature pertaining to the use of IOC or alternative intra-operative methods for imaging the biliary tree in LC. Two authors assembled the evidence in favour, and two authors assembled the evidence against.

RESULTS

From this controversies piece we found that there is little discernible change in the number of BDIs requiring repair procedures. Although IOC is associated with a small absolute reduction in bile duct injury, there are other confounding factors, including a change in laparoscopic learning curves. Alternative technologies such as intra-operative ultrasound, indocyanine green imaging, and increased access to ERCP may contribute to a reduction in the need for routine IOC.

CONCLUSIONS

In spite of 30 years of accumulating evidence, routine IOC remains controversial. As technology advances, it is likely that alternative methods of imaging and accessing the bile duct will supplant routine IOC.

Gallbladder-associated hospital admission and cholecystectomy rates across Australia and Aotearoa New Zealand (2004-2019): Are we over-intervening?

Backgrounds/Aims

To investigate if the increase in the number of cholecystectomies is proportional to symptomatic gallbladder-associated hospital admissions in Australia and Aotearoa New Zealand (NZ).

Methods

National healthcare registries were used to obtain data on all episodes of cholecystectomies and hospital admissions for patients ≥ 15 years from public and private hospitals.

Results

Between 2004 and 2019, in Australia, there have been 1,074,747 hospital admissions and 779,917 cholecystectomies, 715,462 (91.7%) of which were laparoscopic, and 163,084 admissions and 98,294 cholecystectomies in NZ. The 15-54 years age group saw an increase in operative rates, +4.0% in Australia and +6.6% in NZ, and admissions, +3.7% and +5.8%, respectively. Hospital admissions decreased by -9.8% in Australia but the proportion of patients undergoing intervention increased by 10.8% (from 67.1% to 75.0% of hospital admissions). Procedural rates increased by +7.3% in NZ with no change in the intervention rate.

Conclusions

In Australia, there has been a decline in symptomatic gallbladder-associated hospital admissions and a rise in intervention rate. Admissions and interventions have increased proportionally in NZ. There are higher rates of cholecystectomy and admission amongst younger demographics, compared to historical cohorts. Future research should focus on identifying risk factors for increased disease and operative rates amongst younger populations.