Left-sided gallbladder: A rare biliary tree anomaly

Faio Rondelli ,Walter Bugiantella ,Christian Ivan Zapana Chillitupa ,Claudio Marai ,Mihele De Rosa ,∗

a Department of Surgical and Biomedical Sciences,School of Medicine,University of Perugia,Via G.Dottori,06100,Perugia,Italy

b General and Specialized Surgery Unit,“Santa Maria” Hospital,Via T.Di Joannuccio,1,05100,Terni,Italy

c Department of General Surgery,“Nuovo San Giovanni Battista” Hospital,Usl Umbria 2,Via M.Arcamone,1,06034,Foligno,PG,Italy

TotheEditor:

Hepatobiliary anatomical variations may increase the complexity of surgery with a relevant risk of iatrogenic lesions.Left-sided gallbladder (LSG) is a rare and little known condition whereby the viscus is located on the visceral surface of the left lobe of the liver and is often discovered unexpectedly during surgery.The position of the gallbladder over the liver pedicle and the simultaneous presence of variations in the liver vascularization are potentially associated to a challenging surgical dissection and consequently to an increased risk of morbidity.Despite open approach remains an option in more complex procedures,cholecystectomy is usually performed with a minimally invasive technique,which is generally safe even in the rare case of an LSG,as long as a high level of awereness of anatomical variations and a careful surgical dissection are pursued.

A 65-year-old female,with a history of right upper quadrant abdominal pain,accessed emergency department and was referred to our surgical unit for a calculous cholecystitis detected by an abdominal ultrasound.History taking did not reveal jaundice,dark urine,pale stools or pruritus,while physical examination showed a soft,non-tender abdomen,with a right upper quadrant guarding on deep palpation.Past medical history was remarkable for high blood pressure,dyslipidemia,type 2 diabetes mellitus and prosthetic incisional hernia repair.Liver function tests were grossly within normal range and liver ultrasound showed a slightly thickwalled gallbladder with multiple calculi.The patient was scheduled for an emergency laparoscopic cholecystectomy (LC).During surgical exploration the gallbladder was found in the midline against the left lobe of the liver between segments III and IV,to the right of the falciform ligament.The fundus was surmounted by an island of ectopic liver tissue.The cystic duct was narrow and followed its course to the common hepatic duct,while the cystic artery was found anterior to the cystic duct.As a result of these findings,a “fundus first” approach was used.The gallbladder was detached from the liver bed and the gallbladder structures were identified and secured,with no further anatomical abnormalities noted intraoperatively (Fig.1).A Jackson-Pratt drain was left under the liver.The operation was completed in 60 min,the blood loss was negligible,and no intraoperative complication was recorded.The postoperative course was uneventful,the abdominal drain was removed on postoperative day 1 and the patient was discharged on postoperative day 2.The pathological examination revealed a gallstone cholecystitis.

Fig.1.A : Intraoperative picture of left-sided gallbladder;B : “fundus first” approach;C : critical view of safety achieved with clear identification of cystic elements and clipping of cystic artery;D : clipping of cystic duct after section of the artery.

By the end of the fourth week of human embryonic development,the gallbladder and extra-hepatic biliary tree arise from the caudal part of the hepatic diverticulum which appears from the ventral foregut when this process is completed;in relation to the liver,the gallbadder is usually located to the right side,lying under segments IVb and V [1].Agenesis,duplication,wandering,multiseptate and ectopic gallbladder are rare congenital anomalies reported in literature;the location may also change with documented variants including intrahepatic,left-sided,transverse and retro-displaced gallbladder [2].LSG,firstly described in 1886 by Hochstetter [3],represents an uncommon congenital variant with a reported prevalence of 0.1%-0.7% [2].A true LSG located to the left of the round ligament,with the cystic artery always crossing in front of the common bile duct from right to left,or a medial displacement of the gallbladder to the base of the quadrate lobe(mediaposition),but remaining to the right of the falciform ligament,have been reported [4].Despite a low incidence,a number of additional anatomical anomalies in the hepatobiliary and gastrointestinal systems have been described in association with LSG [5].Variations in biliary anatomy may increase the risk of complications during cholecystectomy,abnormalities of the portovenous system are of major importance when more complex hepatobiliary procedures are planned,such as liver resection or transplantation [6].

A clinical picture similar to what is observed in patients with normally positioned gallbladder is reported in 75% of patients with LSG [7].Regardless of gallbladder position,the visceral pain fibres follow the usual pathways,therefore patients affected by symptomatic gallstones will still present with pain in right upper quadrant and positivity of Murphy’s sign will be usually observed in cholecystitis [8].Abdominal ultrasound is the first-line imaging study of biliary pain,but this anatomical variation is usually not detected on preoperative ultrasound [9].An absent liver segment IV or abnormal intrahepatic portal vein branching may be identified raising the suspicion of LSG [4].

Although preoperative diagnostic tools such as computed tomography or magnetic resonance may help in the diagnosis of LSG,most patients with symptomatic gallstones do not require secondline imaging,thus over 80% cases of LSG can only be discovered at surgery [9].In our case,the patient complained of typical colicky right upper quadrant pain,and abdominal ultrasound failed to show the left-sided position of the gallbladder,which was detected at the moment of the operation.

LC of an LSG is a safe procedure,but the variations of the biliary duct,portal vein and other structures may raise the risk of bile duct injuries up to 7.3% [10],significantly more than the incidence usually reported in general population undergoing LC [11].Once identified at surgery,LSG can be approached straightforwardly,perhaps recruiting an experienced surgeon to assist or introducing modifications to the conventional technique,otherwise surgery can be abandoned and re-planned in order to obtain further imaging to better define the biliary anatomy [7].If doubts persist on the exact biliary tract anatomy,the use of intraoperative cholangiogram is highly recommended before starting dissection procedures [12,13].

In order to ease the laparoscopic procedure and reduce the risk of intraoperative complications,the modification of laparoscopic port positions may be adopted.The placement of subxiphoid trocar to the left of round ligament and the use of operative ports in the left side of the abdomen,or changes in patient’s position (left side up) have been described in several studies [9,14].Right retraction of the falciform ligament,“falciform lift”,or its division and dissection off the left liver may be additional technical tips aimed to facilitate exposure during laparoscopic removal of LGS [15].

In our case,LC was performed with the use of a standard fourport technique and LSG was safely removed using the conventional procedure which was facilitated by the use of “fundus first” approach.The dissection started on the gallbladder fundus,the viscus was detached off the liver bed up to Calot’s triangle,where the cystic duct and artery were identified,thus obtaining the critical view of safety.No further anomaly associated with LSG was identified during the operation,demonstrating how LC could be successfully performed in case of LSG if the basic principles of LC,such as the critical view of safety achievement,are followed.Our experience is consistent with previous reports of safe laparoscopic removal of LSG with the use of classical port placement and conventional LC technique [16,17].Early conversion to open surgery has been advocated [18]but also in this case the achievement of critical view of safety may be challenging making the procedure not free from risks.However,conversion to open surgery may be required as the last resort in case of failure of the laparoscopic method [19].

LSG is a rare anatomical anomaly which is usally incidentally discovered during cholecystectomy for biliary colic or cholecystitis symptoms.Given its rarity,it is important to recognize an LSG in order to anticipate potential anatomical variations thus decreasing the chance of complications after the procedure.Accurate detection of anatomical landmarks allows the correct identification of the cystic duct confluence into the common bile duct and therefore its safe dissection and ligation.Meticulous surgical technique will allow a safe removal of LSG through the conventional laparoscopic approach,but modification of patient position and ports placement may be necessary for the clear and secure identification of vascular and biliary structures.We suggest performing a cholecystectomy with safety criteria,starting from the fundus and isolating Calot’s triangle along the edge of gallbladder.In case of challenging anatomy and inability to safely dissect the gallbladder,a low threshold for conversion to open surgery should be kept.

Acknowledgments

None.

CRediTauthorshipcontributionstatement

FabioRondelli:Conceptualization,Supervision,Writing– review &editing.WalterBugiantella:Writing– review &editing.ChristianIvanZapanaChillitupa:Writing– review &editing.ClaudioMarcacci:Writing– review &editing.MicheleDeRosa:Conceptualization,Supervision,Writing– review &editing.

Funding

None.

Ethicalapproval

Written informed consent for publication was obtained from the patient.

Competinginterest

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.