Ancillaryprocedures
Additional diagnostic procedures that can also be performed using laparoscopic guidance include cholecystocentesis, cholecystography, and portography.
1.6.5.1 Cholecystocentesis and cholecystography
The gallbladder is best evaluated in a right lateral or ventral approach.
The normal gallbladder should be soft and fluctuant and the ductal system should not be distended. Obstructive biliary tract disease is often associated with a hard firm gallbladder and a distended duct system. In these cases, the liver and biliary ducts are also often bile stained and the biliary lymphatics are generally distended.When inflammatory or infectious biliary tract disease is suspected a laparoscopic-guided cholecystocentesis with a 22- gauge, 10-cm or longer needle is used to collect a sample for culture and cytology.1 The needle is directed through the abdominal wall, the gallbladder is punctured, and the contents aspirated (Figure 1.88). It is important to remove as much bile as possible to empty the gallbladder and prevent leakage when the needle is removed. The bile should be submitted for both culture and cytology. It is also important to make sure the aspiration needle is placed through the abdominal wall caudal to the diaphragm. Piercing the diaphragm may produce a pneumothorax from abdominal gas passing into the thoracic cavity through the needle track in the diaphragm.
An alternative technique for gallbladder aspiration involves passing the needle through the right middle lobe of the liver and then into the gallbladder where it is attached to the liver surface. With this technique, bile leakage is minimal because bile drains back into the liver and not into the peritoneal cavity. Performing this technique, however, is difficult because the angle of the needle generally requires traversing the diaphragm.
If obstruction of the extrahepatic biliary system is suspected, an iodine contrast study can also be performed following cholecystocentesis.
To perform cholecystography, a needle is placed into the gallbladder, bile is removed, and a radiopaque iodine contrast agent designed for IV use is injected into the gallbladder.1 A volume of 5-15 ml is usually adequate to delineate abnormalities. Care should be taken not to overly distend the gallbladder in order to avoid leakage. Static radiographs or fluoroscopy are then used to evaluate the bile duct system for any blockages. The contrast agent should normally flow freely into the duodenum.1.6.5.2 Portography
It is possible to evaluate the portal system using laparoscopic guidance.11 Both congenital and acquired portal systemic shunts can be identified using this technique. This procedure should always be performed in conjunction with a liver biopsy. Splenoportography involves placement of iodine radiographic contrast medium into the portal vascular system to outline portal blood flow downstream to where the splenic vein enters the portal vein. Laparoscopic splenoportography should be performed in the radiology suite, so that radiographs can be taken immediately following injection.
Splenoportography requires a left lateral approach. The spleen is located and an 18- to 20-gauge, 10-cm spinal needle with stylet is inserted through the ventrolateral abdominal wall near the area of the spleen. The needle is inserted into the body of the spleen parallel with the long axis of the spleen. The needle should be inserted 1-3 cm into the splenic parenchyma. Once the needle is firmly seated in the spleen, the telescope is withdrawn and the pneumoperitoneum is evacuated. The needle hub is then attached to extension tubing and gently flushed with several milliliters of heparinized saline. It is now also possible to measure splenic pulp pressure in centimeters of water by attaching the extension tubing to a standard water manometer. The pressures in the splenic parenchyma are a reflection of portal blood pressure. Normal splenic pulp pressures range from 10-15 cm of water.13 Animals with portal hypertension will have much higher pressures.
Following pressure measurements an iodine contrast agent intended for intravenous use is hand-injected at a dose of 0.250.5 ml/kg body weight over approximately 10 to 20 seconds. Radiographs are obtained halfway through the injection and immediately after completion of the injection. In almost all cases, one is able to delineate the portal blood flow to document congenital or acquired shunting. We find this procedure to be safe and associated with minimal complications.
An alternative method for portography involves exteriorizing a jejunal vein for direct catheter placement into that vein. The method for jejunal vein presentation is similar to that used for the intestinal biopsy technique.
Table 1.13: Potential laparoscopic complications
Anesthesia related
Veress needle / trocar insertion
■ Injury to abdominal wall vasculature
■ Penetration of organs
■ Perforation of hollow viscus
Insufflation
■ Subcutaneousemphysema
■ Peritoneal tenting
■ Inappropriate insufflation
■ Pneumothorax
■ Gas embolism
Operative complications
■ Bleeding
■ Tissue injury
Technical problems
■ Lack of experience
■ Equipment-related problems
1.6.5.3 Other procedures
A number of other laparoscopic procedures include gastrostomy or jejunostomy feeding tube placement and preventive gastropexy.11,12 For these three techniques, the bowel is exteriorized through a trocar-cannula site. Feeding tubes are then placed or for the case of the preventive gastropexy the antral muscle is sutured to the abdominal wall.
1.6.6