RoS

TaDtlcUdtiptjs(sfmwWatosmpsi

RTmtmfnt

D

RFsCPSL

©P

EDUCATION

ationale and Use of the Critical Viewf Safety in Laparoscopic Cholecystectomy

teven M Strasberg, MD, FACS, L Michael Brunt, MD, FACS

gTbb

doCadt(cds2

tlctdttaccmtcpolcbqtfdtsfo1

he introduction of laparoscopic cholecystectomy was associ-ted with a sharp rise in the incidence of biliary injuries.1

espite the advancement of laparoscopic cholecystectomyechniques, biliary injury continues to be an important prob-em today, although its true incidence is unknown. The mostommon cause of serious biliary injury is misidentification.sually, the common bile duct is mistaken to be the cysticuct and, less commonly, an aberrant duct is misidentified ashe cystic duct.2 The former was referred to as the “classicalnjury” by Davidoff and colleagues, who described the usualattern of evolution of the injury at laparoscopic cholecystec-omy.3 In 1995, we authored an analytical review of this sub-ect and introduced a method of identification of the cystictructures referred to as the “critical view of safety” (CVS)2

Fig. 1). (This approach to ductal identification had been de-cribed in 1992,4 but the term critical view of safety was usedirst in our 1995 article.) During the past 15 years, thisethod has been adopted increasingly by surgeons around theorld for performance of laparoscopic cholecystectomy.5-8

hen the method was initially described, it was done so withbrief description and picture, without a thorough explana-

ion of the rationale for this approach.2 The primary purposef this short communication is to present that rationale so thaturgeons can better apply CVS by understanding why theethod is protective against misidentification. A second pur-

ose is to review the current status of the use of CVS and touggest approaches that might reduce the incidence of biliarynjury through its use.

ationale of the CVShe CVS has 3 requirements.2 First, the triangle of Calotust be cleared of fat and fibrous tissue. It does not require

hat the common bile duct be exposed. The second require-ent is that the lowest part of the gallbladder be separated

rom the cystic plate, the flat fibrous surface to which theonperitonealized side of the gallbladder is attached. The cys-ic plate, which is sometimes referred to as the liver bed of the

isclosure Information: Nothing to disclose.

eceived January 29, 2010; Accepted February 26, 2010.rom the Sections of Hepato-Pancreato-Biliary Surgery and Minimally Inva-ive Surgery, Washington University in St Louis, St Louis, MO.orrespondence address: Steven M Strasberg, MD, Section of Hepato-ancreato-Biliary Surgery, Department of Surgery, Washington University int Louis, Suite 1160, Northwest Tower, 660 South Euclid Ave, Box 8109, St

touis, MO 63110. email: strasbergs@wustl.edu

1322010 by the American College of Surgeons

ublished by Elsevier Inc.

allbladder, is part of the plate/sheath system of the liver.9,10

he third requirement is that 2 structures, and only 2, shoulde seen entering the gallbladder. Once these 3 criteria haveeen fulfilled, CVS has been attained (Fig. 1).

The rationale of CVS is based on a 2-step method foructal identification that was and continues to be used inpen cholecystectomy. First, by dissection in the triangle ofalot, the cystic duct and artery are putatively identified

nd looped with ligatures. Next, the gallbladder is completelyissected off the cystic plate, demonstrating that the 2 struc-ures are the only structures still attached to the gallbladderFig. 2). Incorporation of the freeing of the gallbladder off theystic plate so that the gallbladder is hanging from the cysticuct and artery is superior to simply demonstrating that 2tructures are entering the gallbladder because it shows thatand only 2 structures are attached to the gallbladder.During our early experience with laparoscopic cholecystec-

omy, attempts were made to replicate this open approachaparoscopically.4 However, considerable difficulties were en-ountered. First, it was more difficult laparoscopically to takehe gallbladder off the cystic plate completely without firstividing the cystic duct and artery than it was with the openechnique. Another problem was the gallbladder tended towist on the cystic structures after it was freed from itsttachments to the liver, resulting in greater difficulty inlipping and dividing the cystic artery and duct. In theourse of these laparoscopic attempts to mimic the openethod, it was realized that the same fidelity of identifica-

ion obtained by taking the gallbladder off the cystic plateompletely could be achieved by clearing only the lowerart of the gallbladder off the plate, leaving the upper partf the gallbladder attached. In addition, the twisting prob-em, which occurred when the gallbladder was detachedompletely, was not present when the fundus of the gall-ladder remained attached to the liver. At that point, theuestion became what was the least amount of gallbladderhat must be separated from the cystic plate to achieve theidelity of identification attained when the whole gallblad-er is removed. Logically, the amount is that which allowshe surgeon to conclude that the gallbladder is being dis-ected off the cystic plate itself and not just being separatedrom attachments within the triangle of Calot (Fig. 3A). Inur 1995 article,2 this was demonstrated pictorially (Fig.), as opposed to stipulating a fixed extent of cystic plate

hat had to be exposed, because the area that had to

ISSN 1072-7515/10/$36.00doi:10.1016/j.jamcollsurg.2010.02.053

btTdttacmpbwwdaltdwg

nfedetasdt

dtwphfaaCt3

USiTtng

Fdddsb

Ftpmt

133Vol. 211, No. 1, July 2010 Strasberg and Brunt Critical View of Safety

e cleared to be sure that dissection had been carried ontohe cystic plate could differ somewhat from case to case.he cystic plate, being made of fibrous tissue, usually has aull white appearance (Fig. 3B). Occasionally, it is thin andranslucent, allowing the underlying liver to be seenhrough it (Fig. 4A). In cases with mild inflammation andreolar dissection planes, only a centimeter or so of theystic plate needs to be cleaned free of gallbladder attach-ents to ensure that dissection is actually on the fibrous

late. When there is greater inflammation that distance cane greater because fibrotic chronically inflamed tissuesithin the triangle of Calot can also have the same dullhite color as the cystic plate (see Fig. 4B). The extent ofissection has to be that which results in the method beingn adequate surrogate to dissecting the gallbladder off theiver bed entirely. Therefore, distance dissected needs to behat which makes it obvious that the only step left in theissection—if the cystic structures were to be divided—ould be removal of the remaining attachments of theallbladder to the liver.

Although the Figure that was used to illustrate the tech-ique clearly showed that the bottom of the gallbladder wasreed from the cystic plate (Fig. 1), the rationale was notxplained clearly. Consequently, surgeons might not un-erstand why this is an essential step in the procedure, asxplained here. Sometimes surgeons clear a small area ofhe triangle of Calot above the cystic artery as well as therea between the cystic duct and artery (Fig. 3A) and con-ider that this fulfills the requirements of the method. Itoes not. The making of 2 “windows” alone does not satisfy

igure 1. The critical view of safety. The triangle of Calot has beenissected free of fat and fibrous tissue, however, the common bileuct has not been displayed. The base of the gallbladder has beenissected off the cystic plate and the cystic plate can be clearlyeen. Two and only 2 structures enter the gallbladder and these cane seen circumferentially.

he requirements of CVS. To do so, enough of the gallblad- n

er should be taken off the cystic plate so that it is obvioushat the only step left after division of the cystic structuresill be removal of the rest of the gallbladder off the cysticlate (Fig. 3B). Also, although the common duct does notave to be seen, all fat and fibrous tissue must be removedrom the triangle of Calot so that there is a 360-degree viewround the cystic duct and artery, ie, the CVS should bepparent from both the anterior and posterior (reversealot) viewpoints (Fig. 4). The purpose of the grasper in

he picture of the critical view is to precisely indicate that a60-degree view is required (Fig. 1).

se of the CVS techniquetandard procedure—mild and moderate

nflammation presenthe initial steps in performance of a laparoscopic cholecys-

ectomy are similar in most methods. A pneumoperito-eum is created, ports are inserted under direct vision, andraspers are placed on the gallbladder for retraction. The

igure 2. Identification of the cystic structures at open cholecystec-omy. The gallbladder has been completely dissected off the cysticlate and 2 and only 2 structures are entering the gallbladder. Theethod employs putative identification of the cystic structures in the

riangle of Calot before dissection of the gallbladder off the plate.

ext step is to clear the triangle of Calot of fat and fibrous

tits

mfss

ria ofrly ide

134 Strasberg and Brunt Critical View of Safety J Am Coll Surg

issue. This can be done with a variety of techniques, whichnclude teasing tissue away with graspers or gauze dissec-ors, elevating and dividing tissue with hook cautery, andpreading tissue with blunt or curved dissecting instru-

Figure 4. Different appearances of the cystic pfront of the gallbladder as usually shown. Thegallbladder reflected to the left so that a poster

Figure 3. Difference between 2 “windows” andthe creation of 2 windows, 1 between the cystic d(arrows). This dissection does not fulfill the criteidentified. (B) CVS. Arrow points to whitish clea

plate is thicker and whitish. Both views fulfill criteria

ents. The dissection is commonly performed from theront and the back of the triangle of Calot. Two points ofafety for cautery are that it should be used on low powerettings, typically �30 W and that any tissue to be cauter-

(A) Critical view of safety (CVS) is seen from inc plate is very thin. (B) CVS is seen with theew of the triangle of Calot is shown. The cystic

l view of safety (CVS). (A) Dissection has led tond artery and 1 between the artery and the liverCVS because the cystic plate cannot be clearlyntified cystic plate.

late.cysti

ior vi

criticauct a

for CVS.

iiCotdcufcpsaadtpdaaacOa

rtdtostorlgishimmttiaaops

cm

CTimrtdecfhaesmttsc

Flc

135Vol. 211, No. 1, July 2010 Strasberg and Brunt Critical View of Safety

zed should be elevated off surrounding tissue so that theres no unintentional arcing injury to surrounding structures.autery should be applied in short bursts of 2 to 3 secondsr less to minimize thermal spread to surrounding struc-ures. Also, it is important that only small pieces of tissue beivided at one time because important biliary structuresan be quite small in diameter. Using these approaches, it issually not difficult to clear the triangle of Calot of fat andibrous tissue and take the gallbladder off the bottom of theystic plate when mild or moderate inflammation isresent. Once this is done, there will be 2 and only 2tructures attached to the gallbladder and they can be visu-lized circumferentially. At this point, the CVS has beenchieved and the cystic structures can be divided. If anyoubt exists, as can occur when inflammation is severe,hen more of the gallbladder should be taken off the cysticlate, including right up to the fundus, if necessary. Whenividing the cystic structures, it is our practice to divide thertery first because it is usually shorter than the cystic ductnd doing so permits a longer length of cystic duct toppear. This also facilitates insertion of a catheter in theystic duct for performing intraoperative cholangiography.f course, both structures must be clipped and divided inmanner that avoids tenting injury.Most of the instructions in the literature about the safe

emoval of the gallbladder laparoscopically, such as those inhe preceding paragraph, are related to how the dissection isone. The CVS is not a dissection technique, but rather aechnique of identification. As such, it is related to methodsf safe identification in other aspects of life. For instance,tate hunting regulations stipulate that hunters must seehe head and torso of an animal before firing a shot, aspposed to shooting after seeing legs only. Pilots identifyunways as opposed to taxiways by blinking approachights, white runway lights, and radio beacons. These safe-uards are about identification as opposed to the mechan-cs of hunting or flying. Similarly, it is important for theurgeon to separate dissection and identification in his orer mind. Dissection is temporally linear but identification

s temporally static. Dissection reveals the CVS, but affir-ation that the CVS has been achieved takes place in aoment of time when no dissection is going on. Affirma-

ion of the CVS should take place at a pause in the opera-ion and should be treated like a second timeout. The crit-cal view should be demonstrated and ideally the surgeonnd physician assistant, if present, should agree that it ischieved, just as a pilot and copilot agree on critical pointsf identification when flying an airplane. Using these ap-roaches, CVS is usually achievable in standard laparo-

copic cholecystectomy, in single-incision laparoscopic w

holecystectomy11 (Fig. 5), and in natural orifice translu-enal endoscopic cholecystectomy.8

VS in severe inflammationhe preceding was a description of use of the critical view

n the straightforward cholecystectomy in which there isinimal or moderate inflammation and even when aber-

ant ducts are present. In the latter case, ducts can be foundo cross the triangle of Calot and even unite with the cysticuct, but they will not enter the gallbladder and their pres-nce does not interfere with attaining CVS. However, cir-umstances can be very different when there is severe in-lammation. (Although there are rare descriptions of rightepatic ducts directly entering the gallbladder, this is prob-bly not a result of an anomaly of this type but rather anffacement of the cystic duct by a large stone [as in Mirizziyndrome] under conditions in which the cystic duct ter-inates in a low-lying right hepatic duct. In all such cases,

here will be severe chronic inflammation. Developmen-ally, it is extremely unlikely that the right hepatic ductalystem could bud off the side of the gallbladder. The pre-eding does not refer to the accessory ducts of Lutschka,

igure 5. Critical view of safety (CVS) obtained a single-incisionaparoscopic cholecystectomy. Although the view is rotated counter-lockwise from usual, all the criteria of CVS are present.

hich are minute nonessential ducts that pass through the

cm

cposhfadtvb

vcttddcpbtttjttssvabphmcoctisv

PPHStdcnamvppawtCvCt

FTetaehd

136 Strasberg and Brunt Critical View of Safety J Am Coll Surg

ystic plate to communicate between the gallbladder lu-en and intrahepatic ducts.)Surgeons are more likely to dissect the common bile duct

ircumferentially and believe it is the cystic duct in theresence of severe acute and chronic inflammation.12 Thisccurs because certain factors present under these circum-tances tend to hide the cystic duct and fuse the commonepatic duct to the side of the gallbladder.12,13 It is clearrom operative notes that such circumstances can result incompelling deception that the common duct is the cysticuct. The result in many cases has been bile duct injury.12 Ifhe surgeon is using a method, such as the infundibulariew technique (Fig. 6), and has come around the common

igure 6. The infundibular view technique of ductal identification.he putative cystic duct (CD) been dissected circumferentially to thedge of the gallbladder, obtaining the funnel-shaped view shown inhe lower left diagram. Unfortunately, sometimes the same appear-nce can be given when the common bile duct (CBD) is dissected,specially when severe inflammation is present and the commonepatic duct adheres to the side of the gallbladder and the cysticuct is hidden (lower right diagram).

ile duct thinking that it is the cystic duct, a 360-degree d

iew of a funnel-shaped structure resembling the union ofystic duct and gallbladder can be obtained12 (Fig. 6). Ashis funnel shape is the requirement for identification byhis method (infundibulum � funnel), the common bileuct will often be clipped and divided.12 The common bileuct can be similarly dissected in error when using theritical view technique, but it will not be divided at thisoint because the other conditions for the CVS have noteen met. The cystic artery has not been identified, theriangle of Calot has not been completely cleared, andhe base of the cystic plate has not been displayed. Underhe same inflammatory conditions that lead to biliary in-ury in the infundibular view technique, the surgeon usinghe CVS will have difficulty proceeding after isolation ofhe common bile duct. This is actually desirable and shoulduggest that there is a problem. It is important that theurgeon recognizes when this step in the operation becomesery difficult because it suggests there is a problem anddditional attempts to attain CVS laparoscopically shoulde halted. Options include intraoperative cholangiogra-hy, conversion to open cholecystectomy, or soliciting theelp of a colleague. Stated otherwise, the critical viewethod is superior to the infundibular technique under

onditions of severe inflammation because it is more rigor-us. The patient is protected precisely because the surgeonannot usually achieve a misleading view. However, al-hough CVS will usually protect against making incorrectdentification, it will not protect against direct injury totructures by persistent dissection in the face of highly ad-erse local conditions.

hoto documentation of CVShoto documentation of CVS has been recommended byeistermann and colleagues6 and by the Dutch Society of

urgery,14 although the optimal method for documenta-ion has not been systematically studied. This recommen-ation might gain support especially as newer methods ofholecystectomy, such as single-incision cholecystectomy,atural orifice translumenal endoscopic cholecystectomy,8

nd robotic cholecystectomy are introduced. Photo docu-entation might be achieved by still photos or by short

ideo. Still photographs have the advantage of being readilyrintable and could be added to the patient’s chart.15 Thehotographs are also immediately available for review andre easier to store than video. However, in evaluatinghether CVS has been achieved, surgeons frequently move

he lower end of the gallbladder to scan the triangle ofalot from in front and from behind. As a result, a short

ideo of 20 to 30 seconds, as shown in the video clip ofVS (available online) can more accurately replicate what

he surgeon is viewing for documentation purposes. Anec-

otal experience from our group suggests that for single-

ibe

EYhcbbtpi3iiate

l2rt

wppuawus

tIvggbbadfglggmi

d

rci0titcoatopYatasi

ASAADC

R

137Vol. 211, No. 1, July 2010 Strasberg and Brunt Critical View of Safety

ncision laparoscopic cholecystectomy, a video segment cane superior to still photographs because of the ability toxamine both sides of the hepatocystic triangle.

vidence that CVS prevents biliary injuriesegiyants and colleagues reported on 3,042 patients whoad laparoscopic cholecystectomy using CVS for identifi-ation in the period 2002�2006.7 The study was limitedecause data were obtained from an administrative data-ase and CVS was not used in all laparoscopic cholecystec-omies. One bile duct injury occurred in an 80-year-oldatient with severe inflammation.The injury occurred dur-ng dissection before the CVS was achieved, ie, none of,042 patients having laparoscopic cholecystectomy had annjury because of misidentification. The expected rate ofnjury was between 2 and 4 per 1,000 cholecystectomiesnd most would be expected to result from misidentifica-ion. The actual rate of injury was much lower than thexpected rate.7

Avgerinos and colleagues reported on 1,046 patients havingaparoscopic cholecystectomy in a single institution from002�2007.5 In 998 cases CVS was used. The conversionate was 2.7%. There were 5 bile leaks, which resolved spon-aneously. No major bile duct injuries occurred.5

Heistermann and colleagues reported on 100 patientsho had laparoscopic cholecystectomy using CVS.6 Theurpose of the study was to determine how often it wasossible to attain CVS and demonstrate it with photo doc-mentation. Despite a high incidence of acute cholecystitisnd prior abdominal surgery, 97 of 100 cholecystectomiesere completed laparoscopically after achieving photo doc-mentation of CVS. There was 1 postoperative cystic ducttump leak.6

Wauben and colleagues reported on use of ductal iden-ification techniques inThe Netherlands, including CVS.16

n this survey, it was found that Dutch surgeons used aariety of techniques for ductal identification, but few sur-eons used CVS. Subsequently, the Dutch Society of Sur-ery established a commission to study the problem ofiliary injury in that country. The commission developedest practice guidelines for performing cholecystectomynd adopted CVS as the standard method of performinguctal identification.14 Photo documentation of CVS be-ore division of the cystic duct was recommended in theseuidelines.14 At this time, all Dutch surgeons performingaparoscopic cholecystectomy are expected to follow theuidelines. As yet, there is no published information re-arding whether this policy has been successfully imple-ented or whether it has affected the incidence of bile duct

njury in The Netherlands.In summary, there is no Level I evidence that CVS re-

uces bile duct injury. To prove this claim would require a

andomized trial. The difficulty in performing such a trialan be illustrated as follows: even if there was a 4-foldncrease in the incidence of biliary injury from 0.1% to.4% as a result of introduction of laparoscopic cholecys-ectomy, it would be difficult to detect because a random-zed trial would require 4,500 patients per arm to detecthat difference at a 95% confidence level. The logistics andost of performing a surgical trial of this magnitude areverwhelming. Probably the best that can be achieved is thell or none Level I type of evidence, in which it is shownhat biliary injuries resulting from misidentification do notccur when a particular technique is used; from a practicalerspective, that would be sufficient. The case series ofegiyants and colleagues7 and Avgerinos and colleagues5

pproach that standard. The results of the Dutch best prac-ices initiative will be of great interest and might providedditional support for CVS if the policy is implementeduccessfully and if it results in a reduction in biliary injuriesn The Netherlands.

uthor Contributionstudy conception and design: Strasbergcquisition of data: Strasberg, Bruntnalysis and interpretation of data: Strasberg, Bruntrafting of manuscript: Strasbergritical revision: Strasberg, Brunt

EFERENCES

1. A prospective analysis of 1518 laparoscopic cholecystecto-mies. The Southern Surgeons Club. N Engl J Med 1991;324:1073–1078.

2. Strasberg SM, Hertl M, Soper NJ. An analysis of the problem ofbiliary injury during laparoscopic cholecystectomy [see com-ments]. J Am Coll Surg 1995;180:101–125.

3. Davidoff AM, Pappas TN, Murray EA, et al. Mechanisms ofmajor biliary injury during laparoscopic cholecystectomy. AnnSurg 1992;215:196–202.

4. Strasberg SM, Sanabria JR, Clavien PA. Complications oflaparoscopic cholecystectomy. Can J Surg 1992;35:275–280.

5. Avgerinos C, Kelgiorgi D, Touloumis Z, et al. One thousand lapa-roscopic cholecystectomies in a single surgical unit using the “criti-cal view of safety” technique. J Gastrointest Surg 2009;13:498–503.

6. Heistermann HP, Tobusch A, Palmes D. [Prevention of bile ductinjuries after laparoscopic cholecystectomy. “The critical view ofsafety”]. Zentralblatt fur Chirurgie 2006;131:460–465.

7. Yegiyants S, Collins JC, Yegiyants S, Collins JC. Operative strat-egy can reduce the incidence of major bile duct injury in lapa-roscopic cholecystectomy. Am Surg 2008;74:985-957.

8. Auyang ED, Hungness ES, Vaziri K, et al. Natural orifice trans-lumenal endoscopic surgery (NOTES): dissection for the criticalview of safety during transcolonic cholecystectomy. Surg Endosc2009;23:1117–1118.

9. Couinaud C. The vasculo-biliary sheaths. In: Couinaud C, ed.

Surgical anatomy of the liver revisited. Paris; 1989:29–39.

1

1

1

1

1

1

1

138 Strasberg and Brunt Critical View of Safety J Am Coll Surg

0. Strasberg SM, Linehan DC, Hawkins WG. Isolation of rightmain and right sectional portal pedicles for liver resection with-out hepatotomy or inflow occlusion. J Am Coll Surg 2008;206:390–396.

1. Hodgett SE, Matthews BD, Strasberg SM, Brunt LM. Singleincision laparoscopic cholecystectomy (SILC): initial experiencewith critical view dissection and routine intraoperative cholan-giography. Surg Endosc 2009;23:S332.

2. Strasberg SM, Eagon CJ, Drebin JA. The “hidden cystic duct”syndrome and the infundibular technique of laparoscopiccholecystectomy—the danger of the false infundibulum. J Am

Coll Surg 2000;191:661–667.

3. Strasberg SM, Strasberg SM. Error traps and vasculo-biliary injuryin laparoscopic and open cholecystectomy. J Hepato-Biliary-Pancreatic Surg 2008;15:284–292.

4. Gallstone disease (Galsteenziekte) 2007. Dutch Society of Surgery.Available at: http://nvvh.artsennet.nl/richtlijnen/Bestaande-richtlijnen.htm [in Dutch]. Accessed January 27, 2010.

5. Plasier PW, Pauwels MMA, Lange JF. Quality control in lapa-roscopic cholecystectomy: operation notes, video or photoprint. HPB (Oxford) 2001;3:197–199.

6. Wauben LS, Goossens RH, van Eijk DJ, et al. Evaluation ofprotocol uniformity concerning laparoscopic cholecystectomy

in the Netherlands. World J Surg 2008;32:613–620.