Interventions and operations

Once a diagnosis has been made of liver or biliary tree pathology via clinical examination, laboratory data in combination with radiologic imaging, a care strategy to relieve symptoms and address the pathology is made. Often, this strategy involves radiologic interventions, surgery, or a combination of these two modalities. Careful planning and a clear understanding of the underlying disease must guide the choice of intervention. A thorough discussion of all potential invention strategies is beyond this text but we will discuss the more common procedures seen on the clinical wards.

Gallstones and their related complications are one of the most common hepatobiliary abnormalities seen in the clinical wards. As previously discussed, all symptomatic cholelithiasis and asymptomatic cholelithiasis in high-risk groups such as the elderly and diabetics, should be surgically addressed. However, in case of a common duct stone, choledocholithiasis, endoscopic retrograde pancreatography (ERCP), or interventional radiology techniques (percutaneous transhepatic cholangiogram [PTC] with percutaneous biliary drainage [PBD] catheter placement) are favored as first-line therapy for duct drainage and stone retrieval over surgical bile duct exploration. Open common duct exploration has been associated with much higher morbidity and mortality than ERCP for common duct stones. Surgery is strongly indicated for removal of the gallbladder once the common duct stone has been addressed. In the case of cholangitis in the presence of chole-docholithiasis, immediate bile duct drainage is required either endoscopi-cally, via PBD or surgically as well as broad-spectrum antibiotic coverage.

For uncomplicated gallstone disease, the laparoscopic approach for removal has become standard in most patient populations. While previous surgery is not always a contraindication for laparoscopy, inability to adequately visualize the arterial and biliary anatomy during the procedure is an absolute indication to convert to an open procedure. Cirrhosis, ascites, chronic obstructive pulmonary disease (COPD), previous biliary surgery, and portal hypertension are a few absolute contraindications for laparo-scopic cholecystectomy. If a bile duct injury occurs during a cholecystectomy, and is recognized at the time of the procedure, repair by a trained colleague familiar with techniques of biliary reconstruction is recommended. Frequently, the biliary injury occurs as a result of thermal conduction from the electrocautery. Biliary reconstruction via a Roux-en-Y hepaticojejunostomy is usually indicated and preferred. A hepaticojejunostomy is an anastomosis between the side of bowel (usually jejunum) and the common bile duct. Enteral continuity is restored with a side-to-side enteroenterostomy. This technique of biliary reconstruction is commonly used in large liver resections that involve the bile duct as well as in transplantation for specific patient populations such as pediatric patients, procedures such as living donor transplants, and disease states that involve the biliary tree, such as primary sclerosing cholangitis.

For neoplasms of the liver, surgical resection is often warranted. The principles of resection are the same for both benign and malignant disease; resect the lesion with an adequate margin leaving enough functional liver behind to avoid hepatic failure. Although, the liver has regenerative capacity, one should not remove more than 75 percent of the liver parenchyma at the time of resection. This resection threshold may be lower (i.e., even less may be removed) in patients with abnormal liver parenchyma, such as cirrhosis or fatty liver. A clear understanding of liver anatomy is paramount. The hepatectomy can be performed in multiple ways and depends on the anatomy involved with the disease process. Resections can include nonanatomic resections, anatomic segmental resections, anatomic lobe or sectoral resections (left lobe segments = II, III, and IV; right lobe = V, VI, VII, and VIII; segment I, the caudate, can be taken with either the left or the right), and complete hepatectomy at the time of transplantation. In order to facilitate the choice of resection, preoperative imaging is mandatory. Once the decision has been made to proceed with resection, some additional staging technique is used in the operating room to assist in the decisions regarding extent of resection and often, to assess resectability in cases of malignancy. These techniques include staging laparoscopy and intraoperative ultrasound (IOUS). While staging laparoscopy can predict resectability in the majority of cases of primary malignant liver tumors, IOUS is more sensitive for detecting occult liver metastasis not found on traditional imaging. Appropriate staging is important if you are resecting patients with colorectal metastases. Surgical principles are constant.

To minimize blood loss during the resection and demarcate the area to be resected, isolation of the inflow vasculature that is relevant to the area to be resected is performed prior to transecting the liver parenchyma. There are multiple methods of liver parenchymal transection. The classic method is the finger fracture technique where a clamp, or the surgeon's fingers, is used to bluntly transect the liver tissue with the identified vascular and biliary structures ligated, clipped, or cauterized. There are many other methods of parenchymal transection including using devices such as the ultrasonic cav-itron device or a saline enhanced radiofrequency ablation (RFA) device. The choice of transection technique is left to the surgeon. To further minimize blood loss in larger resections, a Pringle maneuver is often performed. The Pringle involves temporary clamping of the porta hepatic. A noncirrhotic liver can tolerate this warm ischemia for up to 30 min. Occasionally, in larger resections, ligation of the hepatic vein responsible for that portion of liver is also ligated prior to parenchymal dissection to further minimize blood loss. At the completion of the parenchymal transaction, hemostasis is obtained and any small biliary leak or bleeding on the parenchymal surface is controlled with suture ligation. Drains are often placed to drain any potential bile leak or to detect bleeding. Complications after liver resection include hemorrhage, abscess, pleural effusions, bile leak, and hepatic failure.

In those patients with colorectal metastasis who are not candidates for traditional resections but have only liver disease, local control techniques offer an alternative to cure. RFA uses high frequency alternating current that destroys tissue via thermal mechanisms. It is delivered to the tumor area either percutaneously under CT guidance, laparoscopically with laparoscopic US, or via the open technique in the operating room assisted by IOUS. Local reoccurrence or persistence of the tumors occurs in 7 percent of patients, usually at the periphery of the ablation field. RFA is often a palliative procedure.23 Other local techniques of tumor control include microwave coagulation and local alcohol injection. Alcohol injection is reserved for patients where cure is not possible and is a palliative therapy.

Finally, there is the surgical therapy of portal hypertension and end-stage liver disease (Table 11-3). Within the past decade, the available treatment options for patients with bleeding varices and portal hypertension from cirrhosis has changed. Surgical shunts, once the therapy of choice in both the emergency and elective setting, have largely been replaced by endoscopic and interventional radiology techniques. In the emergency setting, endo-scopic sclerotherapy or banding have become the interventions of choice to control variceal bleeding.24 The placement of a transjugular intrahepatic portosystemic shunt (TIPS) is now being performed more commonly than surgical shunts, mainly as a bridge to liver transplantation. The TIPS involves placement of a stent into the suprahepatic cava, through the liver parenchyma, and into the portal vein via interventional radiologic techniques. It is highly effective in decompressing varices in the emergency setting but carries the risk of worsening encephalopathy. Other indications for TIPS in patients with symptoms of portal hypertension resulting from cirrhosis may include refractory ascites, portal gastropathy, and the hepatorenal syndrome.25 Surgical shunts are warranted only in those patients with refractory bleeding varices who have failed medical therapy and are not candidates for TIPS who have appropriate anatomy. While there are numerous surgical shunts described, the most commonly performed surgical shunt currently is the distal splenorenal shunt or Warren shunt. The Warren shunt entails anastomosing the distal end of the splenic vein with the left renal vein and disconnecting the significant venous collaterals such as the left gastric and gastroepiploic veins. Preoperative angiogram is mandatory to confirm portal vein patency and assess the size of the splenic vein, which should be greater than 1 cm.26

Table 11-3 Model/Mayo End-stage Liver Disease Score: Log-based Score Using PT INR, Bilirubin (mg/dL), and Creatinine (mg/dL)

Score

3-Month Mortality (%)

<10

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook


Post a comment