A sufficient incision from the xiphoid to the pubis must be created for the entire abdomen to be accessible. Therefore, the abdomen must be appropriately clipped, prepped, and draped. The clipping should extend from ≈4 cm cranial to the xiphoid to ≈4 cm caudal to the cranial brim of the pubis. The abdomen should be clipped ≈3 to 4 cm lateral to the nipples. The entire clipped area should be prepped with initial skin cleaning and the prepuce flushed with dilute 0.05% chlorhexidine diacetate solution1 in a sufficient volume to result in mild distention of the prepuce. The fluid should be agitated in the prepuce, then drained and repeated for a total of 2 minutes. The patient should then be placed in the operating room, and a sterile surgical scrub should be performed, after which the patient can be draped. The drapes should be applied ≈2 cm from the hairline, 2 cm cranial to the xiphoid, and 2 cm caudal to the pubis. For male dogs in which the urethra does not need to be accessed during surgery, the prepuce should be towel clamped out of the field prior to quarter draping. Once the prepuce is lateralized, the quarter drape should be placed over the preputial orifice. If the urinary tract needs to be accessed during surgery (eg, to facilitate urocystolith removal), the prepuce should remain in the surgical field.
The linea alba should be identified and incised.2 In female dogs, the skin, subcutaneous, and fascial incisions should be made on the ventral midline. In male dogs, the skin incision should be curved around the prepuce, and the subcutaneous tissue should be dissected to identify the linea alba.
Following incision through the linea alba, the falciform fat can be visualized attached along the ventral midline. This fat should be inspected for abnormalities (eg, acquired portosystemic shunts, metastatic disease), then removed from each side of the midline using electrosurgery or scissors and ligated cranially at the level of the xiphoid. Ligation of the falciform fat helps prevent hemorrhage from the normal vessels coursing through the fat.
Once the falciform fat is removed, the edges of the incision should be covered with moistened laparotomy pads. Use of an abdominal retractor (eg, Balfour retractor) is important to allow the surgeon to easily inspect the entire abdomen. Once the retractor is in place, the abdomen should be quickly examined for active hemorrhage or lesions that require immediate attention. If none are detected, the systematic abdominal exploration can commence.
Often, the surgeon will divide the abdomen into imaginary sections: cranial, right dorsal, left dorsal, midventral (which includes the GI tract), and caudal. The cranial abdomen is often inspected first. The liver should be gently retracted caudally with a flat hand to examine the diaphragm. Then, each liver lobe should be inspected. The liver lobes from left to right are: left lateral, left medial, quadrate, right medial, right lateral, and the caudate process of the caudate lobe. The papillary process of the caudate lobe is located cranial to the lesser curvature of the stomach, dorsal to the lesser omentum. The caudate process of the caudate lobe and the right lateral liver lobes can be more easily seen during inspection of the right dorsal abdomen.
Examining the biliary tree during liver inspection is ideal. The gallbladder is located between the right medial and quadrate lobes of the liver. When indicated, it can be gently squeezed with continuous gentle pressure to assess patency of the biliary tree. The cystic and common bile ducts can be inspected by gently retracting the gallbladder with attached quadrate and right medial liver lobes cranioventrally and retracting the duodenum caudally. The common bile duct courses through the hepatoduodenal ligament to empty in the duodenum ≈2 to 3 cm aboral to the pylorus.
Next, the right dorsal abdomen, often referred to as the right gutter, should be inspected. The right gutter can be accessed by gently grasping the descending duodenum and using the mesoduodenum as a retractor. The duodenum should be lifted and retracted medially to expose the right dorsal abdominal structures. While the right gutter is exposed, the caudate process of the caudate lobe, the right lateral lobe of the liver, and the right limb of the pancreas can be more easily visualized. The caudate process of the caudate lobe is located dorsally, cupping the right kidney and often overlying the right adrenal gland. The right adrenal gland may not be visualized, but it can be palpated for masses. The portal vein and caudal vena cava can be seen best while the right gutter is exposed. To examine the left dorsal section/left gutter, the descending colon can be grasped on the left side of the abdomen, lifted, and pulled toward the right body wall, using the mesocolon as a natural retractor and exposing the left dorsal abdominal structures. The left adrenal gland can easily be seen cranial to the left kidney.
The spleen is a mobile structure. It can be grasped gently and lifted to facilitate full inspection. All surfaces of the spleen should be evaluated, along with the vasculature supplying it. Siderotic plaques (Figure) are a common, normal finding. The size of the spleen can be variable based on the condition of the patient and the drugs that have been administered.