Current concepts in hepatobiliary surgery

Surgical Anatomy of the Gastrointestinal Tract in Cats

In cats, the gastrointestinal tract is one of the regions in which surgical procedures are most frequently performed by veterinary surgeons; therefore, knowledge of the surgical anatomy of the feline gastrointestinal tract is of high importance. The main surgical procedures performed include gastrotomy, gastrectomy, enterotomy, and enterectomy, as well as procedures in the liver and pancreas. There are also anatomical differences between dogs and cats, increasing the need for deep knowledge of the anatomy treated in the different surgical approaches. The aim of the present review is to describe in detail the anatomy of the gastrointestinal tract in cats highlighting the anatomical regions of significant importance in different surgical procedures.

CT features of divisional bile ducts in healthy Labrador Retrievers

Computed tomography (CT) is increasingly being used for the study of gallbladder and bile duct diseases. The first step in interpreting CT findings is understanding the cross-sectional anatomy of the structures involved, but there are no published studies describing the CT features of the divisional bile ducts. In dogs, anatomic studies report two common patterns including three or four divisional bile ducts. The aim of this retrospective, descriptive, anatomical study was to describe the size and pattern of the visible divisional bile ducts, based on their location and extension, using contrast-enhanced CT in a group of Labrador Retrievers without evidence of hepatobiliary diseases. The correlation between the biliary duct number and dimensions, and the visceral fat area percentage (VFA%) was also evaluated. The right lateral divisional duct (RLD) was visualized in four of 40 dogs, the left lateral divisional duct (LLD) in nine of 40 dogs, and in 17 of 40 dogs, both were simultaneously visualized. In 10 of 40 dogs, the RLD and LLD were not highlighted. When visible, the RLD has a median diameter of 0.23 cm and a median length of 0.82 cm. The LLD has a median diameter of 0.23 cm and a median length of 2.72 cm. The median diameter of the common bile duct before and after the insertion of divisional bile ducts was 0.23 and 0.25 cm, respectively. No correlation with the VFA% was found. At least one of the divisional bile ducts could be visualized using contrast-enhanced CT in the majority of sampled dogs (75%) .

Preliminary Studies on the Intrahepatic Anatomy of the Venous Vasculature in Cats

Hepatic surgeries are often performed in cats to obtain a disease diagnosis, for the removal of masses, or for the treatment of shunts. Whereas the vascular anatomy of the liver has been studied in dogs, such evidence is lacking in cats. The current study used corrosion casts of portal and hepatic veins and computed tomography (CT) analysis of the casts to identify and describe the intrahepatic anatomy in healthy cat livers (n = 7). The results showed that feline livers had a consistent intrahepatic portal and venous anatomy, with only minor disparities in the numbers of secondary and tertiary branches. The feline portal vein consistently divided into two major branches and not three, as previously described in the literature for cats. The finding of a portal vein originating from the right medial lobe branch leading to the quadrate lobe in 4/7 specimens is a novelty of the feline anatomy that was not previously described in dogs. Partial to complete fusion of the caudate process of the caudate and the right lateral lobe, with a lack of clear venous separation between the lobes, was present in two specimens. These findings allowed a detailed description of the most common intrahepatic venous patterns in cats. Further anatomical studies should be encouraged to confirm the present findings and to investigate the utility of this information in surgical settings.

Surgical Management of Feline Extrahepatic Biliary Tract Diseases

Extrahepatic biliary obstruction occurs infrequently in cats. Pathophysiology of biliary obstruction is characterized by cholestasis, obstruction, inflammation, and exudation. Clinical signs and laboratory examination findings are nonspecific. Ultrasonographic examination of the biliary tract aids significantly in diagnosis. The aims of feline biliary surgery are to determine the underlying cause and extent of the obstruction, restore bile flow to the gastrointestinal tract, and prevent bile leakage and subsequent peritonitis. Surgical techniques to restore bile flow and decompress the biliary distension include cholecystostomy tube placement and choledochal stenting, cholecystectomy, choledochotomy, and biliary diversion procedures. Surgical management of extrahepatic biliary obstruction carries a fair to guarded prognosis. Cats undergoing biliary diversion procedures have poorer outcomes than those undergoing nondiversion procedures. Cats with neoplastic involvement have significantly shorter lives than those with inflammatory involvement.

Laparoscopic left hemihepatectomy in small dogs: an easy and effective new technique

The present report describes a novel approach to and presents the surgical results for laparoscopic hepatectomy of the left lobes in small dogs. A purely laparoscopic four-port approach was used in seven beagles. The left triangular ligament was cut first, then the base of the left medial lobe (LMB) was ligated with silk thread using a needle, and the liver parenchyma of the LMB approximately 0.5 cm above the ligation site was removed with LigaSure. The left lateral lobe (LLB) was removed in the same manner. Blood was collected on postoperative days 1, 3, 7, and 14 for laboratory testing. Left hepatic lobe resection was successfully completed in all dogs, with an average operation time of 102.53 ± 9.07 min and an average blood loss of 32.10 ± 6.43 ml. Serious postoperative complications were not observed. The white blood cell (WBC) count and alkaline phosphatase (ALP) level were significantly increased in experimental dogs 1 day after surgery (P< 0.05); aspartate transferase (AST) and alanine transaminase (ALT) were significantly different before and after surgery (P< 0.01); and all the indicators were basically normal seven days after the operation. Exploratory laparoscopy at 28 days revealed adhesion of the surface of the liver section to the omentum or the gastric wall, but there were no other abnormal findings. The combined application of liver pedicle ligation and LigaSure for liver lobectomy provides a simple and effective method for generating liver lobectomy models for research on liver disease and regeneration and a feasible laparoscopic liver lobectomy operation scheme for small dogs (10–15 kg).

Demonstrating the presence of Ehrlichia canis DNA from different tissues of dogs with suspected subclinical ehrlichiosis

Background

Nowadays, Ehrlichia canis receives increasing attention because of its great morbidity and mortality in animals. Dogs in the subclinical and chronic phases can be asymptomatic, and serological tests show cross-reactivity and fail to differentiate between current and past infections. Moreover, there could be low parasitaemia, and E. canis might be found only in target organs, hence causing results to be negative by polymerase chain reaction (PCR) on blood samples.

Methods

We evaluated by PCR the prevalence of E. canis in blood, liver, spleen, lymph node and bone marrow samples of 59 recently euthanised dogs that had ticks but were clinically healthy.

Results

In total, 52.55% of the blood PCRs for E. canis were negative, yet 61.30% yielded positive results from tissue biopsies and were as follows: 63.15% from bone marrow; 52.63% from liver; 47.36% from spleen; and 15.78% from lymph node. In addition, 33% had infection in three tissues (spleen, liver and bone marrow).

Conclusions

Our results show the prevalence of E. canis from tissues of dogs that were negative by blood PCR. Ehrlichia canis DNA in tissue was 30% lower in dogs that tested negative in PCR of blood samples compared to those that were positive. However, it must be taken into account that some dogs with negative results were positive for E. canis in other tissues.

Suspected Gallbladder Torsion in a Juvenile German Shepherd Dog

An 11 mo old intact female German shepherd dog was presented with a 1 day history of vomiting, abdominal pain, and lethargy. A complete gallbladder torsion with secondary bile leakage was diagnosed during exploratory laparotomy. The dog underwent cholecystectomy at the clearly demarcated border of the viable cystic duct and recovered with no complications. Torsion was possible as a result of the complete absence of normal connective tissue attachments to the hepatic fossa, in human medicine called a wandering gallbladder. No other abnormalities were found on complete abdominal exploration. Very few cases describe torsion of the cystic duct as a cause for extrahepatic biliary disease and secondary bile peritonitis in dogs.

Incidence of blood transfusion requirement and factors associated with transfusion following liver lobectomy in dogs and cats: 72 cases (2007-2015)

OBJECTIVE To determine the incidence of blood transfusion, mortality rate, and factors associated with transfusion in dogs and cats undergoing liver lobectomy. DESIGN Retrospective case series. ANIMALS 63 client-owned dogs and 9-client owned cats that underwent liver lobectomy at a specialty veterinary practice from August 2007 through June 2015. PROCEDURES Medical records were reviewed and data extracted regarding dog and cat signalment, hematologic test results before and after surgery, surgical method, number and identity of lobes removed, concurrent surgical procedures, hemoabdomen detected during surgery, incidence of blood transfusion, and survival to hospital discharge (for calculation of mortality rate). Variables were compared between patients that did and did not require transfusion. RESULTS 11 of 63 (17%) dogs and 4 of 9 cats required a blood transfusion. Mortality rate was 8% for dogs and 22% for cats. Pre- and postoperative PCV and plasma total solids concentration were significantly lower and mortality rate significantly higher in dogs requiring transfusion than in dogs not requiring transfusion. Postoperative PCV was significantly lower in cats requiring transfusion than in cats not requiring transfusion. No significant differences in any other variable were identified between dogs and cats requiring versus not requiring transfusion. CONCLUSIONS AND CLINICAL RELEVANCE Dogs and cats undergoing liver lobectomy had a high requirement for blood transfusion, and a higher requirement for transfusion should be anticipated in dogs with perioperative anemia and cats with postoperative anemia. Veterinarians performing liver lobectomies in dogs and cats should have blood products readily available.