The gallbladder lies within the hepatic fossa that is bordered by the right medial and quadrate lobes of the liver. There is a variably well-adhered attachment of the gallbladder fundus and body to the hepatic parenchyma of these lobes. The neck of the gallbladder tapers to the beginning of the cystic duct. The cystic duct extends from the gallbladder neck to the point at which the first hepatic duct joins. It is just distal to the junction of the first hepatic duct that ligation of the cystic duct takes place during LC. The common bile duct continues toward its insertion into the duodenum at the major duodenal papilla in dogs and cats and receives tributary hepatic ducts that number two to eight in dogs.¹⁹ The blood supply to the gallbladder is through the cystic artery that is a branch of the hepatic artery. The cystic artery lies in close association with the cystic duct, and the two structures are usually ligated together during LC.

Candidates for LC should receive a thorough diagnostic evaluation before undergoing the procedure. Comorbidities need to be ruled out, and a thorough evaluation of the pathology of the hepatobiliary tract needs to be obtained. A complete blood count and biochemical evaluation along with a urinalysis should be obtained. Elevations in hepatobiliary enzymes and total bilirubin are commonly found in dogs with gallbladder disease and should be noted. There may be an association between certain endocrinopathies and GBM formation in dogs with one study demonstrating that 21% of dogs with GBM were diagnosed with concurrent hyperadrenocorticism.²⁰ Changes associated with hyperadrenocorticism, such as elevations of alkaline phosphatase and cholesterol, present on preoperative blood work in the presence of consistent clinical signs should prompt an endocrinologic evaluation for the condition. Evaluation of coagulation status is also warranted in this patient population despite the incidence of significant coagulopathy being relatively low because significant hemorrhage is possible during dissection.²¹

Diagnostic imaging is an equally important part of the preoperative diagnostic evaluation. Thoracic radiographs are indicated to rule out clinically significant comorbidities in the thorax. Abdominal radiographs are usually nonspecific, although most choleliths in cats and dogs are radiopaque as they are most often composed of calcium bilirubinate (most common in dogs) or calcium carbonate (most common in cats).^18,19 Abdominal ultrasonography is a vital part of the preoperative diagnostic evaluation and can provide critical evaluation of gallbladder wall thickness, size, presence of choleliths, pericholecystic inflammation, and degree to which mucus is filling the lumen in cases with GBM.²² Ultrasonographic characteristics of GBM have been described and often include enlargement of the gallbladder with a typical immobile stellate or finely striated ultrasonographic appearance (“kiwi” gallbladder).¹⁰ Characteristics of the cystic and common bile ducts such as diameter (normal common bile duct diameter in cats and dogs is ∼3–4 mm), discontinuity, and presence or absence of choledocholithiasis or masses involving the area can usually be diagnosed. Changes can be monitored over time with repeated ultrasound examinations providing vital information on whether changes are progressive or static. This is important information because extrahepatic biliary tract distension can remain after an episode of EHBO, so the presence of distension does not always indicate current obstruction.

Because so few LCs have been reported to date in veterinary patients, case selection has not been thoroughly evaluated and is largely based on anecdote. In dogs with GBM, it is suggested that EHBO is a contraindication for LC at this point in time because of the risk of persistent postoperative EHBO. The thick, sludgy bile that is produced in the gallbladder readily moves down into the common bile duct and hepatic ducts, and in patients with evidence of obstruction, it is recommended that a technique that allows flushing of the bile from the common duct be performed. This is despite a recent study that failed to show a significant difference in outcome in dogs undergoing cholecystectomy for GBM that had common bile duct flushing compared with those that did not.¹⁴ Common bile duct flushing has not been reported to date in conjunction with LC. In general, if the serum total bilirubin is significantly elevated or if there is ultrasonographic evidence of obstruction demonstrated by significant common bile duct or gallbladder enlargement, the authors suggest that an OC be pursued. In the future, if development of endoscopic retrograde cholangiography (ERC) or laparoscopic common bile duct exploration can be perfected in these species, the prospect of performing LC in animals without a patent common bile duct may become an option. ERC has been documented in healthy research animals but not yet in a significant population of clinical patients with EHBO.^23,24

A further contraindication to LC in patients with gallbladder disease is evidence of bile peritonitis. If discontinuity of the extrahepatic biliary tract is present, thorough evaluation for leakage of bile from one or more sites should be performed, and this may be challenging to do laparoscopically. Additionally, because of the ability of bile salts to contribute to severe chemical peritonitis and the high mortality rate associated with bile peritonitis (especially when bacterial infection is present) in small animal patients, thorough lavage of the entire peritoneal cavity should be performed.^9,25 Despite some reports in humans of laparoscopic treatment of bile peritonitis,^26,27 it is unknown whether lavage can be performed as effectively laparoscopically as it can via a celiotomy approach. Future studies may find that less invasive peritoneal drainage techniques are adequate for management of dogs with bile peritonitis, but at present, data have not been reported in small animal patients.

In dogs and cats with symptomatic or asymptomatic cholelithiasis, LC may potentially be indicated. Again, obstructive disease and the presence of bile peritonitis should be ruled out in these patients before proceeding with LC. The presence of choleliths in the common bile duct is a contraindication for LC given the need to remove the stones by retrograde flushing or choledochotomy. Necrotizing cholecystitis may be an indication for LC, although many of these canine patients present with rupture of the biliary system and bile peritonitis at presentation, so LC should be used with caution in this cohort of patients.²⁸

In preparation for LC in dogs and cats, a wide clip of the entire abdomen from 5 cm cranial to the xiphoid process to the caudal prepuce or vulva caudally is recommended. Laterally, the patient should be clipped to the dorsal third of the abdominal wall to allow dorsally positioned ports to be placed. The entire area is aseptically scrubbed for surgery.