Effect of intended intraoperative cholangiography and early detection of bile duct injury on survival after cholecystectomy: population based cohort study

BMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e6457 (Published 11 October 2012)
Cite this as: BMJ 2012;345:e6457

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2 November 2012

First of all we would like to thank Dr Farid and colleagues for their interesting and valuable comments on our article: Effect of intended intraoperative cholangiograpy and early detection of bile duct injury on survival after cholecystectomy: population based cohort study.

Dr Farid and his colleagues raise a question regarding the severity classification of bile duct injuries (BDI) used in our study. The Strasberg classification is without doubt widely used and has advantages mainly due to its simplicity. However, this grading system, in similarity with all others, has limitations. For example, a small lateral incomplete injury to the common bile duct may often safely be addressed with simple suturing, whereas extensive lateral injuries at or above the hepatic confluence almost always require reconstruction with hepatico-jejunostomy. Both of these injuries are classified as Strasberg D. As a more detailed subanalysis regarding different BDI and survival could not be performed without significant loss of power, we chose the subdivison of injuries into severe and less severe depending on required intervention. Information in the registry regarding the extent of the injury often makes this severity grading possible resulting in 55 out of 178 injuries to major ducts being classified as severe. Moreover, postoperatively detected injuries are usually discovered by the 30 day follow-up as bile leakages and the lack of information regarding extent and localization of some injuries is mainly due to limited clinical work-up rather than limitations within the registry.

The analyses of intraoperative cholangography (IOC) and survival include the whole spectrum of BDI, from cystic duct leaks and minor lesions to transected major ducts. Dr Farid and his colleagues’ stipulated lack of association between these injuries and IOC can be questioned. One of the arguments against IOC use has been that cystic duct cannulation may in fact cause injuries to the cystic duct with a subsequent higher risk of cystic duct leakage. Moreover, the survival benefits seen with IOC among these cases might, as pointed out, be either due to the detection of common bile duct stones and the subsequent prevention of a secondary cystic stump blow-out or early identification of aberrant ducts/Luschka ducts. These possible mechanisms of causality between minor injuries and IOC were among the reasons for inclusion into the survival models.

The main focus of this study was on survival after cholecystectomy in general and after BDI in particular. Thus, the relationship between IOC usage and BDI incidence has only been briefly covered without further subanalyses with respect to different injury locations and severities and possible confounders. This is of course of great interest and importance and is going to be a major part of a coming GallRiks-based study on risk factors for bile duct injury.

One of the drawbacks of this registry is that the reason for performing/not performing IOC isn’t documented. We are thus unable to control for the safe-surgeon-factor. It is possible, and even likely, that a part of the protective effect of IOC is due to that some IOC-users are more likely to perform “safe surgery”. These surgeons might have reduced complication rates due to a generally safe approach rather than because of a protective effect by the IOC use per se. On the other hand, selective IOC use only in situations of difficult anatomy or suspected BDI, may cause a “difficult situation”-biased association between complications/BDI and IOC, thus diluting a possible protective effect.

Of course this study does not unequivocally prove a causal chain of: IOC-use > less BDI > lower mortality. However, this large, prospective cohort study does show a strong, multivariately adjusted, association between the use of IOC and improved survival after cholecystectomy as well as a significant association between the use of IOC and a reduced risk of BDI. More research is warranted to establish the full causal chain of events.

Competing interests: None declared

Björn Törnqvist, Consultant surgeon

Magnus Nilsson

Division of Surgery, CLINTEC, Karolinska Institutet and Department of Surgical Gastroenterology, Karolinska University Hospital, Huddinge, Karolinska University Hospital, 141 86 Stockholm, Sweden

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What was the proportion of episodes of bile duct injury in patients with laparoscopic cholecystectomy vs counterparts with open cholecystectomy in the above study? With that kind of information patients would be in a postition to make an evidence-based decision for preferring one treatment modality to another

Competing interests: None declared

oscar,m Jolobe, retired geriatrician

manchester medical society, Simon Building, Brunswick street Manchestr M13 9PL

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We read with interest the recent article by Törnqvist and colleagues highlighting the role of intraoperative cholangiography (IOC) on the detection of bile duct injuries (BDI) during laparoscopic cholecystectomy (LC) and on patient survival [1]. The authors are congratulated on the establishment and maintenance of a prospective GallRisks national registry in Sweden incorporating more than 50000 patients. The authors attempt to address and challenge the long standing debate regarding the utility of IOC during LC and conclude with an alarming statistic to all those involved in either being a purchaser, provider and receiver of this common procedure – namely that “ the intention to perform IOC reduces the risk of death by 62% after LC”. However we wish to add some caution to the interpretation of results by highlighting potential limitations in the study, reflecting on related published literature, clinical practices and perhaps equally topical; the implication of such results in the current NHS economic crisis.

Databases such as presented here deliver statistical power by numbers and clearly has inherent advantages. However we have some reservation in the application of the hypothesis model to the database that may have contributed to the study outcomes. The authors state that there is no international consensus as to the definition of severe and less severe bile duct injury and instead use their definition relating to severity based upon required intervention. The Strasberg classification [2] published in 1995 has become the gold standard of classification of bile duct injuries and allows comparison of the severity of injuries between series. To the reader this change in definition compared to other studies is confusing, as injuries to the major duct ducts occurred in 178 cases but the authors only defined 55 (31%) of them as being severe. Furthermore in a prospectively maintained database 191/747 (25.5%) of injuries were “not classifiable”? Surely, the presence of injuries has been documented, investigated and managed and so the type of injury should be known to the surgeon managing the patient and hence communicated to GallRisks. If 1 in 4 injuries are not being accurately reported we would suggest this is a cofounding factor and impacting on the power of this database analysis.

Another controversial area in our opinion is the inclusion of cystic duct and duct of Luschka leaks in the analysis relating to IOC as it is unlikely to have influenced the prevalence of either lesion (unless in the presence of common duct stones). We do however agree with the authors that their documentation is important. Likewise, major strictures, in our opinion should have been classified in relation to the biliary/vascular injury that caused them. The incidence of bile duct injury was noted to be 29% lower if IOC was attempted/performed but this figure includes ALL injuries and is not a fair representation. We propose a fairer comparison to have been made by comparing injuries that would have been detected by IOC and thus provide more accurate information on its utility. Also in relation their Cox proportional hazards model, intending to carry out IOC carries the same benefit as performing it. This may suggest that experienced surgeons suspecting an injury were more aware of potential/actual damage and intervened with IOC and allowed for early diagnosis and management rather than the actual act of IOC per se. An argument that raises the debate between correlation and causation. The mortality rates for all patients undergoing cholecystectomy would appear high not just those with biliary injuries but for the overall population as a 1 in 100 risk is certainly noteworthy - a multivariate analysis of factors associated with mortality would have been very useful for both patient groups and/or at the very least whether deaths were related or unrelated to BDI.
Numerous clinical and cost effectiveness studies to date have yet to provide sufficient evidence to convince the wider general surgical community to embrace routine IOC [3-6]. Furthermore a more recent survey concluded that the accuracy of detection of both normal and variants of normal anatomy was poor in all grades of surgeon irrespective of a policy of routine or selective IOC [7]. However this study is the first to report a more than 60% reduction in mortality of patients following LC if IOC is undertaken – completed or performed. While there is no denying the detrimental impact on quality of life and morbidity associated with BDI and all efforts to reduce this are to be encouraged, our current hospital practice continues to use IOC in selective cases only and complements the critical view of safety technique in all LC’s. The findings presented in this article will fuel the debate no doubt and attract interest from the GP considering referral to a surgeon who performs routine IOC or not or perhaps most interesting of all – the patient presenting in outpatients next month asking if they can have a IOC as it would reduce mortality risk by 62 % - far greater than reduction of death by motorcycle helmets (42%) and using a seatbelt to improve chance of surviving a potentially fatal crash (40-60%)! [8-9].

Shahid Farid,
Specialist Registrar, Northampton General Hospital

Colin Hart,
Specialist Registrar, Northampton General Hospital

Gareth Morris-Stiff
Consultant Surgeon, Belfast City Hospital, Belfast

1. Törnqvist B, Strömberg C, Persson G, Nilsson M. Effect of intended intraoperative cholangiography and early detection of bile duct injury on survival after cholecystectomy: population based cohort study. BMJ 2012; 345: e6457. doi: 10.1136/bmj.e6457.
2. Strasberg SM, Hertl M, Soper NJ. An analysis of the problem of biliary injury during laparoscopic cholecystectomy. J Am Coll Surg 1995; 180: 101-25.
3. Livingston EH, Miller JA, Coan B, Rege RV. Costs and utilization of
intraoperative cholangiography. J Gastrointest Surg. 2007 Sep;11(9):1162-7. Epub
2007 Jun 30. PubMed PMID: 17602271.
4. Lill S, Rantala A, Pekkala E, Sarparanta H, Huhtinen H, Rautava P, Grönroos
JM. Elective laparoscopic cholecystectomy without routine intraoperative
cholangiography: a retrospective analysis of 1101 consecutive cases. Scand J
Surg. 2010;99(4):197-200. PubMed PMID: 21159587.
5. Sajid MS, Leaver C, Haider Z, Worthington T, Karanjia N, Singh KK. Routine
on-table cholangiography during cholecystectomy: a systematic review. Ann R Coll
Surg Engl. 2012 Sep;94(6):375-80. PubMed PMID: 22943325.
6. Metcalfe MS, Ong T, Bruening MH, Iswariah H, Wemyss-Holden SA, Maddern GJ. Is
laparoscopic intraoperative cholangiogram a matter of routine? Am J Surg. 2004
Apr;187(4):475-81. Review. PubMed PMID: 15041494.
7. Sanjay P, Tagolao S, Dirkzwager I, Bartlett A. A survey of the accuracy of
interpretation of intraoperative cholangiograms. HPB (Oxford). 2012
Oct;14(10):673-6. doi: 10.1111/j.1477-2574.2012.00501.x. Epub 2012 Jun 11. PubMed
PMID: 22954003; PubMed Central PMCID: PMC3461373
8. Liu BC, Ivers R, Norton R, Boufous S, Blows S, Lo SK. Helmets for preventing injury in motorcycle riders. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD004333. DOI: 10.1002/14651858.CD004333.pub3.
9. http://www.fiafoundation.org/thinkbeforeyoudrive/about/think_facts.html.... 22/10/2012 18.51 hrs

Competing interests: None declared

Shahid Farid, General Surgical Specialist Registrar

Colin Hart, Gareth Morris-Stiff

Northampton General Hospital, Cliftonville, Northampton, NN5 5HQ

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Gall stone disease is one of the major surgical problems in Libya.Laproscopic cholecystectomy is reported to have biliary complications. The authors suggest that early recognition and immediate management of biliary injuries is dependent on individual resources and circumstances but, if required, consultation with colleagues or referral of patients with suspected or established biliary complications should not be delayed.
The study emphasizes the fact that proper LC should be performed in hospitals with facility to perform ERCP or when access for this technique is available in a nearby institution.

Competing interests: None declared

dhastagir s sheriff, Professor

Faculty of Medicine, Benghazi University, Benghazi, Libya

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