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Stomach
Chapter
28
Stomach Z. Halfacree
This chapter discusses the surgical diseases of the stomach in the cat. Simple gastric surgery, in particular gastrotomy for foreign body removal or full-thickness gastrointestinal biopsy, is sometimes indicated in the cat. More involved gastric surgery, such as gastric resections and pyloroplasty are encountered less frequently. This chapter includes an overview of the preoperative and perioperative considerations for cats undergoing gastric surgery and a summary of the indications for gastric surgery. The surgical techniques for commonly indicated procedures, including gastrotomy and tube gastrostomy, are discussed in detail and the techniques used for pyloric surgery are summarized.
SURGICAL ANATOMY AND PHYSIOLOGY The stomach is positioned in the cranial abdomen at the level of the costal arch, sitting within the concavity of the visceral surface of the liver (Fig. 28-1). The position of the stomach varies depending upon filling and the size of the surrounding viscera. A cat’s stomach can accept 300–350 mL of liquid.1 Ingesta enters the stomach at the cardia, passing through the lower esophageal sphincter. In the cat this sphincter is comprised of an oblique gastric sling muscle, which lies on the left lateral aspect of the sphincter, and a circular muscle that fully encircles the distal esophagus.2 Ingesta exits the stomach via the pylorus; although the exact mechanisms are not clear, it is evident that the pylorus plays an essential role in coordinating gastric motility and gastric emptying.3 The vascular supply of the stomach is derived from the celiac artery, which branches into the hepatic artery, left gastric artery, and splenic artery. The right and left gastric arteries are situated along the lesser curvature and the right and left gastroepiploic arteries situated along the greater curvature of the stomach. A few branches from the splenic artery (short gastric arteries) supply the fundus. The hepatic artery gives rise to the gastroduodenal artery before continuing as the right gastroepiploic artery. In turn, the gastroduodenal artery supplies the cranial pancreaticoduodenal artery, which is responsible for the vascular supply to the proximal duodenum.4 The parasympathetic innervation is supplied by the vagus nerve and its dorsal and ventral vagal trunks that supply branches to the stomach © 2014 Elsevier Ltd DOI: 10.1016/B978-0-7020-4336-9.00028-7
as they pass through the esophageal hiatus. The sympathetic innervation arises from the splanchnic nerves, with the post-ganglionic fibres from the celiacomesenteric ganglion traveling along the branches of the celiac artery. The feline enteric nervous system is composed of two ganglionated plexuses.5 The gastric lymphatic system drains to the gastric, hepatic, or splenic lymph nodes.1 The gastric lymph nodes are located on the lesser curvature of the stomach within the lesser omentum and are inconsistently present.6 The mesenteric structures supporting the stomach are known as the greater and lesser omentum. The greater omentum is composed of parietal and visceral layers and each layer is composed of two peritoneal sheets. A meshwork of blood vessels and lymphatics running within strands of adipose tissue lies between the fine sheets, creating a net-like appearance. The visceral layer of the greater omentum originates at the dorsal abdominal wall in common with the transverse mesocolon and extends caudally, covering the ventrolateral aspect of the small intestines. At the level of the pelvic inlet the omentum is reflected upon itself to form the parietal layer of the greater omentum
Figure 28-1 A computed tomography scan in transverse section of an adult domestic short-haired cat demonstrating the position of the stomach within the concavity of the visceral surface of the liver.
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Figure 28-2 Topographic anatomy in the normal cat: the tips of the forceps are inserted into the epiploic foramen in the craniodorsal abdomen.
Figure 28-3 A needle foreign body in the stomach of a cat. The cat had ingested a needle and thread and the radiopaque needle is clearly visible.
that lays adjacent to the ventrolateral abdominal wall and continues cranially to insert on the greater curvature of the stomach. The stomach sits between the two sheets of the greater omentum and these then converge at the lesser curvature of the stomach to form the lesser omentum. The potential space between the visceral and parietal layers of the omentum is called the omental bursa. Access to this space is gained via the epiploic foramen (Fig. 28-2) in the craniodorsal abdomen, or surgically by gently creating a small opening through the greater omentum, into the omental bursa. The left limb of the pancreas is present between the sheets of the visceral layer of the greater omentum adjacent to the dorsal aspect of the stomach and the spleen is situated between the sheets of the parietal layer of the greater omentum. The portion of greater omentum extending between the greater curvature of the stomach and the spleen is referred to as the gastrosplenic ligament.
DIAGNOSIS AND GENERAL CONSIDERATIONS
Figure 28-4 An ultrasound image demonstrating a mass involving the cardia of the stomach in a 1-year-old domestic short-haired cat. (Courtesy Alison Moores; © Anderson Moores Veterinary Specialists.)
Hematology, serum biochemistry, serum electrolytes, and urinalysis are routinely performed in cats with gastric disease. Gastric ulceration may lead to anemia and serum electrolytes may be deranged in any patient suffering from vomiting. Vomition and loss of chloride, potassium, and acid-rich gastric secretions can lead to hypochloremic hypokalemic metabolic alkalosis; however, acid–base imbalances can be complex and hypovolemia may lead to metabolic acidosis.7
Inflated thoracic radiography, including both lateral projections, is indicated in patients in which neoplasia is suspected to screen for metastatic pulmonary disease. In patients suffering from regurgitation thoracic radiography is advised to identify evidence of aspiration pneumonia.
Diagnostic imaging
Gastroscopy
Plain abdominal radiography can be valuable in diagnosis of intraluminal foreign bodies (Fig. 28-3) and gastric distension. In order to identify gastric mucosal or mural lesions using radiography, contrast studies may be necessary. However, ultrasonography is frequently rewarding for evaluating these lesions (Fig. 28-4) and often eliminates the need for contrast studies of the stomach in these patients. Approximately 30% of normal cats have submucosal fat which appears as a radiolucent line within the gastric wall on radiography;8 it is important to note that this is a normal finding. Studies of gastric motility and gastric emptying often rely upon fluoroscopic contrast studies.9 Nuclear scintigraphy is the gold standard for monitoring of gastric transit times and gastric emptying.10
Gastroscopy can be extremely useful in the management of gastric disease. It provides an unrivalled perspective of the gastric lumen and mucosal surface and may reveal lesions eluding other imaging modalities, which could also be missed on external evaluation of the stomach at laparotomy. Endoscopy allows biopsy samples to be obtained for histopathology, thereby providing prognostic information and aiding surgical planning if appropriate (Fig. 28-5). Unfortunately, the mucosal surface of neoplastic lesions may be necrotic or inflamed and histopathology can be misleading.11 Gastroscopy is also a useful technique to allow retrieval of foreign bodies without the need for surgery. However, the withdrawal of very large or sharp objects through the cardia and esophagus should be avoided.
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Figure 28-5 Two images captured during gastroscopy performed in an 11-year-old domestic short-haired cat with a history of weight loss and vomiting. Cytologic and histopathologic specimens obtained at gastroscopy confirmed a diagnosis of large cell lymphoma.
SURGICAL DISEASES Full thickness gastric biopsy and gastric foreign body removal are the most common reasons for performing gastric surgery in the cat. Other less common indications include surgery for management of gastric outflow disease, neoplasia, and gastroduodendal perforation and addressing gastric dilatation associated with diaphragmatic rupture.
Gastric foreign bodies Gastric foreign bodies are occasionally seen in the cat, but due to the relative dietary discretion of this species they are far less common than in the dog. The most common gastric foreign bodies include trichobezoars (fur balls) and linear foreign bodies, such as a needle and thread (see Fig. 28-3). Foreign bodies may be responsible for vomiting secondary to gastric outflow obstruction, initiation of gastritis or intestinal plication. They may be seen as incidental findings on abdominal radiographs in the absence of clinical signs. Where facilities and expertise permit, endoscopic retrieval of gastric foreign bodies is preferable to surgery unless the nature of the foreign body suggests that damage to the cardia or esophagus may occur during retrieval.
Linear foreign bodies The most common site of anchorage of linear foreign bodies in the cat is under the tongue (Fig. 28-6); however, anchorage at the gastric pylorus is also seen.12 Plication of the duodenum and jejunum occurs as intestinal peristalsis attempts to move the anchored foreign body aborally, resulting in a functional and/or structural intestinal obstruction; however, unlike the dog, secondary intussusception has not been observed.12,13 The radiographic appearance of linear foreign bodies does not conform to the classical picture of dilated loops of small intestine normally associated with intestinal obstruction and could lead to the diagnosis being overlooked. Thorough patient evaluation together with inspection of the abdominal radiographs for bunching of the small intestine, potentially in an abnormal position, and irregular accumulations of small intestinal gas should alert the clinician to the diagnosis. Removal of the linear foreign body requires release of the anchorage point, which is commonly at the base of the tongue or the gastric pylorus. Surgical management should be performed promptly following release at the base of the tongue, since loss of intestinal plication may expose areas of intestinal perforation and allow leakage of intestinal contents. When the anchorage site is at the pylorus a
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Figure 28-6 Lateral thoracic and abdominal radiograph of a 1-year-old female neutered domestic short-haired cat with a cotton thread linear foreign body lodged under the cat’s tongue. A barium study had previously been performed. The small intestines appear bunched in the cranial abdomen with an irregular contrast pattern. Barium has been absorbed by the cotton thread, highlighting the path of the cotton through the thoracic esophagus from the oral cavity to the abdomen (arrows).
combination of gastrotomy and one or more enterotomy incisions may be required. Initially, a gastrotomy is performed in the distal aspect of the gastric body allowing access to the most proximal portion of the foreign body. Gentle traction can be applied to attempt retrieval via the gastrotomy site; however, caution must be exercised to prevent further damage to the mesenteric border of the small intestine. If any resistance is experienced the foreign body must be removed in pieces; the large portion present within the gastric lumen is sectioned from the portion extending into the small intestine allowing the plication effect to be released. The remaining portion of the linear foreign body is removed through additional enterotomy incisions as required and gastrotomy and enterotomy sites are closed routinely. Careful inspection of the mesenteric border of the small intestine is essential to determine if perforation or necrosis of the intestinal wall has occurred. Multiple sites of intestinal resection and anastomosis can be necessary; however, the incidence of intestinal perforation and requirement for intestinal resection anastomosis is far lower in the cat compared to the dog.12,13 It has been theorized that the thinner, less bulky, nature of linear foreign bodies in cats is responsible for a lesser degree of intestinal plication, resulting in a lower morbidity and mortality in this species in comparison to the dog.13 Based upon review of the literature, it is suggested that the probability of septic peritonitis and death secondary to a linear foreign body is approximately half that in a cat in comparison to a dog.12,13 A technique has been described via which linear foreign bodies may be removed through a single enterotomy in the cat.14 The linear foreign body is secured to a red rubber catheter that is inserted into the intestinal lumen and milked towards the anus, together with the intestinal foreign body. Due to the difference in the nature of the foreign bodies they ingest, this technique is unlikely to be applicable to the dog, but it should always be considered in the cat. The authors describe that this technique would be applicable when the anchorage site was within the stomach; however, the catheter would be introduced via the gastrotomy and advanced aborally towards the anus. Conservative management of linear foreign bodies in the cat has been described with successful outcome.15 This involved identifying the anchorage site of the foreign body under the tongue and releasing it, therefore allowing the foreign body to pass. This could be considered if surgical intervention is not possible due to financial constraints; however, due to the risk of gastrointestinal perforation
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the author would advocate surgical management via exploratory laparotomy.
Pyloric stenosis Gastric dysfunction is seen in young, pure bred cats, in particular Siamese cats.16 They are generally less than 6 months old at presentation. The presenting clinical signs include vomiting, which may be projectile, and weight loss; regurgitation may also be present. Investigations reveal gastric distension and a functional delay in gastric outflow associated with pyloric stenosis (Fig. 28-7). Normal gastric emptying should start within 15 minutes of barium ingestion and the stomach is generally empty in four hours.9 Concurrent megaesophagus is often present (Fig. 28-7) and while primary megaesophagus is suspected, it can be unclear if this is due to secondary esophagitis. Postmortem examination of one cat has documented gastric heterotopia, with secretory gastric mucosa within the distended esophagus, presumably contributing to esophagitis.17 Some cats have been successfully managed medically with postural feeding and gastroprotection; however, when delayed gastric emptying or pyloric stenosis are documented, pyloroplasty is warranted. As this appears to be largely a functional obstruction, pyloromyotomy or Y to U pyloroplasty are likely to be sufficient; a Billroth procedure is not warranted. Tube gastrostomy (see Box 28-3) is recommended due to the potential for altered gastric motility following pyloroplasty in a patient where gastric motility may already be abnormal. The outcome is likely to be influenced by presence of megaesophagus, but the prognosis for resolution of megaesophagus is unclear until resolution of vomiting has been achieved, together with an appropriate period of medical management for esophagitis.
Gastroduodenal ulceration and perforation Gastroduodenal ulceration is occasionally seen in the cat.18–21 Predisposing factors include stress associated with surgery, administration of steroid or non-steroidal anti-inflammatory medication, and as a paraneoplastic syndrome (e.g., systemic effects of mast cell neoplasia or pancreatic gastrinoma).18–21 Several cases reported in the literature have failed to identify an underlying cause. Gastric ulceration and perforation may also occur secondary to primary gastric disease, including neoplasia and inflammatory bowel disease. Clinical signs include inappetence, vomiting, hematemesis, and melena; progression to gastric perforation may result in depression and collapse due to sepsis. Anemia is a common clinical finding in cats with gastrointestinal blood loss; however, it is important to note that hematemesis or melena were present in less than a third of cats with gastrointestinal ulceration in one review.18 Cats that have suffered from gastric perforation may present with depression and abdominal distension due to pneumoperitoneum. Radiographic evidence of marked spontaneous pneumoperitoneum in the cat should raise the suspicion of gastric perforation (Fig. 28-8). Ultrasonographic findings of gastric perforation can be quite nonspecific, with bright regional mesenteric fat and peritoneal effusion noted most frequently.22 Abdominal radiography is advocated to facilitate detection of pneumoperitoneum. Tension pneumoperitoneum causing respiratory embarrassment has been described in a cat with concurrent upper respiratory tract obstruction.23 Therapeutic abdominocentesis may be required in this situation to achieve stabilization; however, this is uncommon. Indications for surgery in cats with gastroduodenal ulceration are listed in Box 28-1. Surgery is invariably required as cats tend to present when disease is advanced and gastric perforation has occurred. Septic peritonitis is a life-threatening condition with a guarded prognosis; its presence necessitates careful patient stabilization and prompt surgical intervention (see Chapter 26). In one study looking at septic peritonitis in cats, with a range of underlying causes, only 12 of 26 cats survived to discharge.24 Thorough exploratory laparotomy, gastric resection at the site of perforation (see Box 28-4), copious lavage, and empirical antibiosis (while pending culture results) are
A
B Figure 28-7 Fluoroscopic barium swallowing study in a 6-month-old male neutered Siamese kitten. (A) The esophagus is moderately dilated along its length. (B) The stomach is distended with food particles, fluid and gas. There is no evidence of barium passing into the small intestines after 15 minutes, suggestive of pyloric stenosis.
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Figure 28-8 A lateral abdominal radiograph of a 5-year-old male entire domestic short-haired cat that presented following discovery of small focal penetrating wounds. The cat had been shot with an air rifle and one of the airgun pellets had perforated the gastric wall.
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Box 28-1 Indications for surgery in cats with duodenal ulceration Failure to respond to medical management Life-threatening gastrointestinal hemorrhage Evidence of gastric perforation
essential. The site of gastric perforation can be challenging to identify and thorough inspection must be performed. Perforation of a gastric ulcer involving the pylorus can present a surgical challenge. The morbidity associated with a Billroth I (pylorectomy and gastroduodenostomy) or Billroth II (pyloroduodenectomy and gastrojejunostomy) is ideally avoided in patients with potentially benign disease. When possible, local debridement and primary closure should be performed in the first instance, avoiding more radical gastric resection which is potentially unnecessary. It is essential that the repair is augmented with omentum or a serosal patch. Tissue must always be obtained for histopathology to rule out gastric neoplasia. Gastric perforation may be caused by trauma; due to the protected site of the stomach within the costal arch the most common traumatic lesion is a ballistic projectile, such as an airgun pellet (Fig. 28-8).
Disorders associated with the esophageal hiatus Gastric disease associated with the esophageal hiatus occurs infrequently in the cat, with only a few case reports available in the literature.25–28 Gastroesophageal intussusception is the term used to describe invagination of the stomach into the lumen of the distal esophagus. Predisposing factors are reported to be megaesophagus, an incompetent lower esophageal sphincter, and chronic vomiting. Presenting signs include regurgitation, vomiting, dyspnea and collapse. The prognosis is considered guarded, but successful outcome has been reported in the dog following prompt diagnosis and intervention.29 Surgical management involves an exploratory laparotomy, reduction of the intussusception, gastropexy, and placement of a stomach tube. Non-surgical management with endoscopic reduction of the intussusception intraluminally and percutaneous endoscopic gastrostomy tube placement has been reported in one puppy.30 In contrast to the dog, in which gastroesophageal intussusception is predominantly a life-threatening condition requiring rapid intervention, intermittent gastroesophageal intussusception with mild chronic clinical signs represents two of the four individual case reports in the cat.26,28 Congenital sliding hiatal hernia has been reported in a small number of cats.31–33 Surgical management, by herniorrhaphy, esophagopexy and incisional gastropexy is reported,31,32 although there was no long term follow up. Successful management by dietary change, with resolution of regurgitation, has also been reported.33 Surgical management of sliding esophageal hiatal hernia has been reported in a lynx, cougar, and a lion.34 For more information on management of hiatal hernia, see Chapter 45.
Gastric disorders associated with diaphragmatic rupture Traumatic diaphragmatic rupture is frequently encountered in the cat (see Chapter 45) and is associated with herniation of abdominal contents, often including the stomach, into the pleural cavity. Rarely, herniation of the stomach into the pleural cavity can result in the
Figure 28-9 A lateral abdominal radiograph of a 4-year-old domestic short-haired cat that presented with acute collapse and dyspnea. The cat has a traumatic diaphragmatic rupture and herniation of the stomach into the pleural cavity with subsequent development of tension gastrothorax. (Courtesy Victoria Lipscomb.)
life-threatening complication of ‘tension gastrothorax’ (Fig. 28-9). Respiratory compromise occurs due to occupation of the pleural space by the stomach which, depending upon position, can become markedly distended by trapped air.35,36 Emergency decompression of the distended stomach is required via passage of a nasogastric tube or percutaneous gastrocentesis. Following stabilization, surgery to reduce the herniated viscera and repair the diaphragmatic rupture must also be performed. Abdominal viscera, including the stomach, may become incarcerated following diaphragmatic rupture and non-viable tissue must be resected (Fig. 28-10). Gastric dilatation and volvulus occurs rarely in cats and diaphragmatic rupture, with the stomach remaining within the peritoneal cavity, appears to be a predisposing factor.37,38 Successful outcome has been reported following appropriate stabilization and gastric derotation at surgery, following the same management approach as for the dog. Gastropexy is advocated; however, the literature indicates this is not consistently performed when the predisposing factor of diaphragmatic rupture has been identified. Sliding hiatal hernia has been reported as a complication following diaphragmatic rupture and diaphragmatic herniorrhaphy in the cat;33 successful surgical management is reported with hiatal herniorrhaphy and tube or incisional gastropexy.
Gastric neoplasia Gastric neoplasia is uncommon in the cat and is generally seen in older animals. Lymphoma is the most commonly reported gastric tumor in the cat and it is not amenable to surgical resection due to the diffuse nature of disease. In comparison to lymphoma at other sites, a histopathologic diagnosis is often required to achieve a diagnosis in visceral lymphoma.39 Even then, it can be difficult to differentiate low grade lymphoma from lymphoplasmacytic enteritis on the basis of cytology and histopathology and therefore other tests such as clonality may be required.40 Most cats are feline leukemia virus negative. Feline gastric adenocarcinoma is rare and the stomach is the least commonly affected gastrointestinal site in the cat.
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A
B
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D
Figure 28-10 A chronic traumatic diaphragmatic rupture in an 8-year-old domestic short-haired cat with herniation of the stomach, small intestines and omentum into the pleural cavity. (A) The diaphragmatic defect in the tendinous portion of the diaphragm following reduction of the herniated abdominal contents. (B, C) A section of jejunum and a region of the gastric wall had become strangulated. (D) The portion of devitalized gastric wall was resected and closed in two layers. (Courtesy Matthieu Cariou.)
PREOPERATIVE CONSIDERATIONS Thorough preoperative investigations are essential to attempt to achieve a diagnosis prior to surgery, therefore allowing a surgical plan to be formulated. Adequate preparation can then be made to prepare the cat for surgery, decide on therapeutics and anesthetic needs, and also to consider the postoperative conditions that will be required.
Surgical considerations Despite preoperative investigations, additional findings may be made at surgery and it is important to perform a full systematic abdominal exploration. Evaluation of a gastric mucosal lesion and its extent can be facilitated by inspection through a gastrotomy made opposite the lesion, thereby aiding intraoperative decision making.
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Perioperative antibiotic use Gastric surgery in which the gastric lumen is entered is classified as clean contaminated surgery, provided appropriate care is taken to ensure minimal intraoperative contamination. Perioperative prophylactic antibiosis is therefore appropriate but postoperative antibiotic administration is not justified.41 Minimal intraoperative contamination is achieved by use of stay sutures to manipulate the gastrotomy, use of laparotomy swabs to isolate the gastrotomy site from the rest of the abdomen, designation of both clean and contaminated areas for surgical instruments, and use of copious peritoneal lavage. Septic peritonitis, due to pre-existing gastric perforation or necrosis, necessitates the use of therapeutic antibiosis postoperatively. This will initially be empirical but should be adjusted based upon culture and sensitivity results from bacteriology samples obtained at surgery.
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Box 28-2 Gastrotomy
Figure 28-11 Stay sutures have been placed in the ventral surface of the stomach to aid in atraumatic manipulation and to reduce the risk of spillage of gastric contents following gastrotomy.
Anesthesia considerations Gastric fluid retention may result in regurgitation with the risk of aspiration at the time of induction. It is important to achieve a smooth induction and intubate the patient promptly; stomach tubes and suction apparatus should be made available. Multimodal analgesia should be provided where possible in patients undergoing a laparotomy. Non-steroidal anti-inflammatory medication is contraindicated in patients that may be suffering from gastrointestinal ulceration and in patients that are hypovolemic. Premedication with systemic gastroprotectant medication (cimetidine or ranitidine) may be indicated in cats with a high risk of gastrooesophageal reflux or regurgitation; elevation of the pH of gastric fluid ameliorates the potential effects upon the esophagus or lungs should regurgitation and/or aspiration occur. For further information on anesthesia see Chapter 2.
Isolate the stomach using moistened laparotomy swabs to pack off other abdominal contents. Place stay sutures in the ventral stomach wall using monofilament suture material, full thickness bites and sutures placed 1 cm apart. Make a stab incision at a non-vascular part of the ventral gastric wall into the gastric lumen, using the stay sutures to ‘tent’ the gastric wall (Fig. 28-12). The stomach wall naturally separates into two distinct layers, with the outer layer including the serosa and muscularis and the inner layer including the submucosa and mucosal layer. Extend the incision using Metzenbaum scissors, making a full thickness cut through the gastric wall. Use suction apparatus to aspirate gastric contents and prevent spillage. If indicated, a full thickness gastric biopsy can be obtained at this stage by excising a portion from the edge of the gastrotomy wound using Metzenbaum scissors. The serosa muscularis and the submucosa mucosal layers will naturally separate. It is recommended to tack the two together with a suture to avoid loss of one half of the biopsy sample. Place additional stay sutures at either wound edge to minimize tissue trauma and facilitate manipulation of the gastrotomy. Remove gastric foreign bodies using swab holding forceps or Allis tissue forceps. Any instruments that were used within the gastric lumen should be discarded and if gloves have become contaminated with gastric contents they should be changed. The gastric wall should be closed in two layers. The author uses a simple continuous appositional suture in both the mucosa/submucosa layer and the outer muscularis/ serosa layer. Absorbable monofilament suture (e.g., polydioxanone, poliglecaprone 25) in 1.5 or 2M is appropriate. Chromic catgut is not recommended. Whenever a gastric foreign body is removed ensure that the stomach and the entire gastrointestinal tract are carefully checked for additional foreign bodies.
SURGICAL MANAGEMENT AND TECHNIQUES The surgical approach to the stomach is via a routine ventral midline celiotomy (see Chapter 23), extending cranially to the level of the xiphoid. Removal of falciform fat is recommended to improve visualization. Increased mobilization of the stomach may be achieved by transection of the hepatogastric ligament and the avascular peritoneal reflection. Manipulation of the stomach is facilitated by placement of stay sutures in the ventral aspect of the stomach to reduce tissue trauma and reduce the risk of gastric contents spillage. The stay sutures should be passed full thickness through the gastric wall to engage the submucosa, with a bite 1 cm in length to avoid suture pull through (Fig. 28-11).
Gastrotomy Gastrotomy (Box 28-2) is commonly indicated for foreign body retrieval, inspection of lesions within the gastric lumen and to obtain full thickness biopsies. The principles of gastrostomy that should be applied prior to performing a gastric resection state that a simple gastrotomy is performed at a site that allows initial luminal inspection without interfering with the subsequent surgical plan.
Figure 28-12 Stay sutures are placed prior to performing a gastrostomy. The stay sutures are used for atraumatic manipulation of the stomach.
Gastrostomy Gastrostomy tube placement in the cat has several indications (Box 28-3). The tube can be inserted per endoscopically (see Chapter 12) or by open surgery (Box 28-4). The latter technique is indicated if the cat is having a celiotomy, if there are not facilities for endoscopic tube placement, or the tubes are not of the type that are ideally placed endoscopically. The major advantage of surgically placed gastrostomy tubes in comparison to percutaneous endoscopic gastrostomy tubes is the reduced risk of peritoneal leakage.42
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The patient can be fed orally with the tube in place and, if ongoing enteral nutrition is required, the cat can be discharged with the tube in place, following appropriate client education.43 The gastrostomy tube should not be removed earlier than ten days postoperatively to ensure satisfactory healing resulting in an adhesion between the gastric and body walls, and therefore avoiding intraperitoneal contamination. While early adhesion formation is promoted in surgically placed gastrostomy tubes by suturing the gastric wall to
Box 28-3 Indications for tube gastrostomy
Nutrition
the abdominal wall, the author still does not recommend early removal. Experimental studies in healthy dogs have reported that the risk of peritoneal contamination is low after three days postoperatively due to adequate adhesion formation;44 however, it is unclear how adhesion formation may be affected by debilitation of the patient. The tube is removed by traction and the stoma is left to heal by second intention. The insertion of a trocar into the lumen of the tube to efface the mushroom tip can be useful to facilitate removal. Sedation or general anesthesia is advisable in the cat. Foley catheters are unsuitable for use as gastrostomy tubes, as degradation of the balloon by exposure to gastric acid may cause premature failure and leakage of gastric contents to occur.
Indications Prolonged inappetence or inability to eat To bypass the oral cavity, pharynx or esophagus Contraindications Primary gastric disease Vomiting patient Used with caution in patients with esophageal dysfunction or altered mentation due to risk of aspiration
Gastric resection
Gastric decompression
Pyloric surgery is infrequently indicated in the cat. Pyloroplasty (Fig. 28-17) is indicated for management of congenital pyloric stenosis (Fig. 28-18), which is associated with delayed gastric emptying. Surgical procedures involving the pylorus may be indicated for management of a discrete gastric tumor or for resection of a perforated area of ulceration (Table 28-1).
Surgery involving the pylorus commonly affects pyloric function and gastric motility postoperatively which may cause gastric retention and inappetence. Placement of a tube gastrostomy allows gastric decompression to be achieved and enteral nutrition to be provided where necessary.
Gastric resection (Box 28-5) is rarely indicated in the cat. It may be indicated for excision of a perforated gastric ulcer (Fig. 28-15), excision of a focal neoplastic lesion, or a devitalized region of gastric wall (see Fig. 28-10).
Pyloric surgery
Gastropexy Gastropexy is seldom indicated in the cat. However, it is recommended in cases of gastric dilatation and volvulus, esophageal hiatal hernia and gastrooesophageal intussusception, that are reported rarely. Tube gastropexy is ideal in these patients both to prevent recurrence of dilation and volvulus and provide nutrition.
POSTOPERATIVE CARE Multimodal postoperative analgesia is provided where appropriate, combining a pure (methadone) or partial (buprenorphine) opioid agonist together with a non-steroidal anti-inflammatory drug if
Box 28-4 Tube gastrostomy technique (Fig. 28-13) Choose an appropriate position for the tube gastrostomy between the body of the stomach and the left body wall, approximately one third of the distance from ventral to dorsal along the body wall and just behind the last rib (Fig. 28-14A). Make a stab incision through the body wall with a number 10 or 15 blade. Pass the external end of the mushroom tipped tube through the body wall using Kelly artery forceps (note the tube is not tunneled at all) (Fig. 28-14A,B). Now block the end of the tube to prevent contamination of the surgical field. Place a purse-string suture in the gastric body at the site where the tube will enter, prior to creating the stab incision (Fig. 28-14C). Insert the mushroom tube via the stab incision. The mushroom tip must be folded within the jaws of a pair of artery forceps to achieve this. Once the tube is inserted (Fig. 28-14D), withdraw it until the mushroom abuts the gastric wall and tie the purse-string suture tight. The stomach is then secured to the body wall using four horizontal mattress sutures between the stomach wall and the body wall, placed around the tube in sequence to create a box of sutures (Fig. 28-14E,F). Omentalize the stoma site by wrapping some omentum around the tube and sutures. Secure the tube externally using a finger trap suture. Additional fixation of the tube is essential prior to recovery from anesthesia to prevent inadvertent removal. This can be achieved using a stockinette dressing or bandaging material.
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Figure 28-13 Diagram summarizing placement of a gastrostomy tube. Only two sutures are shown between the stomach and body wall; usually four would be placed.
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Figure 28-14 Surgical placement of a tube gastrostomy in a cat. See Box 27-4 for details of the technique with a description of parts (A) to (F).
A
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Figure 28-15 Gastric ulceration and perforation in a 5-year-old female neutered Persian cat. (A) Lateral abdominal radiography revealing a pneumoperitoneum. (B) DeBakey forceps indicate the site of gastric perforation on the lesser curvature of the stomach. Local inflammation of the serosal surface is the only apparent abnormality on initial inspection. (C) A full thickness incision is made through the gastric wall adjacent to the lesion to allow inspection of the mucosal surface and evaluate the extent of the lesion. (D, E) A focal area of mucosal erosion is identified on the luminal surface. A focal area of gastric wall with a margin of normal tissue surrounding the ulcer is resected. This will be closed in two layers, as for a standard gastrotomy incision.
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appropriate. Cats that are hypotensive or have evidence of gastrointestinal ulceration should not receive non-steroidal anti-inflammatory drugs. Early enteral nutrition is recommended as soon as the cat has fully recovered from general anesthesia. Intravenous fluid therapy should be continued until normal oral intake of fluid and food is resumed.
dehiscence. Dehiscence of gastrotomy wounds and subsequent septic peritonitis is uncommon; in one study describing the underlying cause of septic peritonitis in cats, none of the cats had developed septic peritonitis due to gastrotomy dehiscence, while five of 26 cats had developed septic peritonitis due to enterotomy dehiscence.25
COMPLICATIONS AND PROGNOSIS Complications associated with gastric surgery include routine surgical complications such as bleeding, wound infection, and wound
Box 28-5 Gastric resection (Fig. 28-16) Perioperative assessment of the gastric mass or lesion, at the time of exploratory laparotomy, is often necessary to establish if resection is feasible. Evaluation of the extent of a focal mass lesion, and feasibility for resection, is often aided by inspection of the mucosal surface of the lesion via a gastrostomy on the opposite side. In some cases (e.g., benign adenomatous polyps), submucosal resection may be appropriate and can be useful for resection of lesions within the pylorus, thereby avoiding more radical surgery. If surgical excision is not straightforward, incisional biopsy of the gastric lesion and regional lymph nodes should be performed to achieve complete surgical staging. Lesions involving the greater curvature may be amenable to resection using surgical stapling equipment (gastrointestinal anastomosis stapler; see Chapter 10). Alternatively, the area that requires resection should be removed using scissors or a scalpel blade. The use of Doyenne bowel clamps, careful use of stay sutures, and a surgical assistant aid the procedure and reduce the risk of gastrointestinal spillage. The stomach should be closed in two layers as for gastrotomy; an additional layer of inverting sutures (e.g., interrupted or continuous Cushing or Lembert sutures) may be used to over-sew the site and reinforce the closure.
A
B
D
E
Figure 28-16 A small lesion can be removed by partial gastrectomy. Closure is achieved by placement of a continuous appositional suture in the two distinct layers of the gastric wall, reinforced by an inverting suture if required.
C
Figure 28-17 A 6-month-old male neutered Siamese kitten undergoing a Y-to-U pyloroplasty. (A) The pyloric region of the stomach appears relatively unremarkable on external examination. (B) A full thickness Y-shaped incision is made over the pylorus with the centre of the Y situated at the pylorus. (C) The luminal surface of the pylorus is inspected. (D) The top portion of the Y created a U-shaped flap, which is advanced aborally to widen the pylorus. (E) The Y-to-U pyloroplasty is complete. (Courtesy Dr Stephen Baines.)
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Table 28-1 Summary of the options for pyloric surgery in the cat Surgical technique
Technique
Indications
Disadvantages
Fredet–Ramstedt pyloromyotomy
Longitudinal incision over the pylorus through the serosa and muscularis layers only, leaving submucosa and mucosa intact
This technique is of limited use
Does not allow inspection of mucosal surface Does not allow full thickness biopsy Improvement in outflow may be short-lived due to narrowing during healing
Heineke Mikulicz Pyloroplasty (HMP)
Full thickness longitudinal incision over the pylorus which is then closed transversely to create widening
Pyloric stenosis
Y-U advancement pyloroplasty (see Fig. 28-18)
A full-thickness Y-shaped incision is made over the pylorus with the leg of the Y oriented towards the duodenum. The created flap is used as an advancement flap creating a U-shaped wound
These are preferable first-line procedures due to simplicity and reduced disruption of pyloric function. Subjectively, the Y-U pyloroplasty creates a greater degree of widening than the HMP and allows greater access to achieve mucosal resection. These techniques may afford limited benefit in patients with severe disease, in particular if muscular hypertrophy is advanced and pylorectomy may therefore be indicated
Pylorectomy and gastroduodenostomy (Billroth I)
End-to-end anastomosis of the distal stomach to the duodenum. Luminal disparity must be corrected and can be achieved by spatulation of the duodenal end or partial closure of the gastrotomy
Severe pyloric stenosis Gastric resection due to neoplasia or severe gastroduodenal ulceration
For neoplastic lesions margins of 1–2 cm should ideally be achieved, but close proximity to the common bile duct and pancreas may preclude this
Partial gastrectomy and gastrojejunostomy (Billroth II)
The distal stomach and proximal duodenum are closed and a side-to-side anastomosis of the jejunum to the diaphragmatic surface of the stomach is created. Surgical stapling equipment can be used Biliary diversion and potentially ligation of the pancreatic duct are also necessary
Gastric resection due to neoplasia or severe gastroduodenal ulceration
Complex surgical procedure resulting in significant long-term postoperative morbidity This technique should be avoided unless all other options have been ruled out Careful client communication regarding morbidity and the need for long-term medical management is essential
A
B
C
Figure 28-18 Y-to-U pyloroplasty for pyloric stenosis. (A) A Y-shaped incision full thickness incision is made just proximal to the pylorus. (B) The first suture, indicated by the arrow, converts the Y to U. (C) Additional sutures are placed to close the gastrotomy.
Comments
Take great care to avoid damage to the common bile duct in its course through the lesser omentum
Surgery involving the esophageal hiatus or the gastric pylorus may interfere with regulation of gastric motility in the postoperative period and therefore patients should be monitored for gastric distension. Occasionally, gastric decompression may be required and is facilitated by prior placement of a tube gastrostomy. Careful monitoring of serum electrolytes is essential if gastric decompression is performed. The feeding of a low fat diet will reduce gastric retention and may ameliorate gastric motility dysfunction.45 Complications of gastrostomy tube placement include peristomal inflammation or infection, premature tube removal, septic peritonitis, and fistula formation after tube removal.42 Stoma site metastasis has been reported associated with gastrostomy tube placement in the human and dog.46 Fungal colonization precipitating tube failure has been reported with long-term use.47
REFERENCES 1. Barone R. Système lymphatique du chat. In: Barone R, editor. Anatomie comparé des mammifères domestiques. Tome 5 angiologie. Paris: Editions Vigot; 1996. p. 833–44. 2. L’Heureux M-C, Muinuddin A, Gaisano HY, et al. Feline lower oesophageal
sphincter sling and circular muscles have different functional inhibitory responses. Am J Physiol Gastrointest Liver Physiol 2006;290:G23–9. 3. Lammers WJ, Slack JR, Stephen B, Pozzan O. The spatial behaviour of spike patches in the feline gastroduodenal junction in
vitro. Neurogastroenterol Mot 2000;12: 467–73. 4. Gilbert SG. Pictorial anatomy of the cat. University of Washington Press; 1968. p. 49–55. 5. Kleinschmidt S, Nolte I, HewickerTrautwein M. Structural and functional
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components of the feline enteric nervous system. Anat Histol Embryol 2011 (epub ahead of print). Schreurs E, Vermote K, Barberet V, et al. Ultrasonographic anatomy of abdominal lymph nodes in the normal cat. Vet Radiol Ultrasound 2008;49:68–72. Bebchuk TN. Feline gastrointestinal foreign bodies. Vet Clin Small Anim 2002;32:861–80. Heng HG, Wrigley RH, Kraft SL, Powers BE. Fat is responsible for an intramural radiolucent band in the feline stomach wall. Vet Radiol Ultrasound 2005;46: 54–6. Hall JA, Washbau RJ. Diagnosis and treatment of gastric motility disorders. Vet Clin Small Anim 1999;29:377–95. Lamb CR. Recent developments in diagnostic imaging of the gastrointestinal tract of the dog. Vet Clin Small Anim 1999;29:307–42. Evans SE, Bonczynski JJ, Broussard JD, et al. Comparison of endoscopic and full-thickness biopsy specimens for diagnosis of inflammatory bowel disease and alimentary lymphoma in cats. J Am Vet Med Assoc 2006;229:1447–50. Felts JF, Fox PR, Burk RL. Thread and sewing needles as gastrointestinal foreign bodies in the cat: a review of 64 cases. J Am Vet Med Assoc 1984;184:56–9. Evans KL, Smeak DD, Biller DS. Gastrointestinal linear foreign bodies in 32 dogs: a retrospective evaluation and feline comparison. J Am Anim Hosp Assoc 1994;30:445–50. Anderson S, Lippincott CL, Gill PJ. Single enterotomy removal of gastrointestinal linear foreign bodies. J Am Anim Hosp Assoc 1992;28:487–90. Basher AW, Fowler JD. Conservative versus surgical management of gastrointestinal linear foreign bodies in the cat. Vet Surg 1987;16:135–8. Pearson H, Gaskell CJ, Gibbs C, Waterman A. Pyloric and oesophageal dysfunction in the cat. J Small Anim Pract 1974;15:487–501. Bishop LM, Kelly DF, Gibbs C, Pearson H. Megaoesophagus and associated gastric heterotopic in the cat. Vet Pathol 1979;16: 444–9. Liptak JM, Hunt GB, Barrs VR, et al. Gastroduodenal ulceration in cats: eight cases and a review of the literature. J Fel Med Surg 2002;4:27–42. Mellanby RJ, Baines EA, Herrtage ME. Spontaneous pneumoperitoneum in two cats. Journal Small Anim Pract 2002;43: 543–6.
20. Lykken JD, Brisson BA, Etue SM. Pneumoperitoneum secondary to a perforated gastric ulcer in a cat. J Am Vet Med Assoc 2003;222:1713–16. 21. Cariou MP, Halfacree ZJ, Lee KC, Baines SJ. Successful surgical management of spontaneous gastric perforations in three cats. J Feline Med Surg 2010;12:36–41. 22. Boysen SR, Tidwell AS, Penninck DG. Ultrasonographic findings in dogs and cats with gastrointestinal perforation. Vet Radiol Ultrasound 2003;44:556–64. 23. Itoh T, Nibe K, Naganobu K. Tension pneumoperitoneum due to gastric perforation in a cat. J Vet Med Sci 2005;67:617–19. 24. Parsons KJ, Owen LJ, Lee K, et al. A retrospective study of surgically treated cases of septic peritonitis in the cat (2000-2007). Journal Small Anim Pract 2009;50:518–24. 25. Van Camp S, Love NE, Kumaresan S. Radiographic diagnosis – gastroesophageal intussusception in a cat. Vet Radiol Ultrasound 1998;39:190–2. 26. Martínez NI, Cook W, Troy GC, Waldron D. Intermittent gastroesophageal intussusception in a cat with idiopathic megaoesophagus. J Am Anim Hosp Assoc 2001;37:234–7. 27. Owen MC, Morris PJ, Bateman RS. Concurrent gastro-oesophageal intussusception, trichobezoar and hiatal hernia in a cat. N Z Vet J 2005;53:371–4. 28. van Geffen C, Saunders JH, Vandevelde B, et al. Idiopathic megaoesophagus and intermittent gastro-oesophageal intussusception in a cat. Journal Small Anim Pract 2006;47:471–5. 29. Graham KL, Buss MS, Dhein CR, et al. Gastroesophageal intussusception in a Labrador retriever. Can Vet J 1998;39: 709–11. 30. McGill SE, Lenard ZM, See AM, Irwin PJ. Nonsurgical treatment of a puppy with gastroesophageal intussusception. J Am Anim Hosp Assoc 2009;45:185–90. 31. Robotham GR. Congenital hiatal hernia in the cat. Fel Pract 1979;9:37–9. 32. Ellison GW, Lewis DD, Phillips L, et al. Esophageal hiatal hernia in small animals: literature review and a modified surgical technique. J Am Anim Hosp Assoc 1987;23:391–9. 33. Bright RM, Sackman JE, Denovo C, et al. Hiatal hernia in the dog and cat: a retrospective study of 16 cases. J Small Anim Pract 1990;31:244–50. 34. Hettlich BF, Hobson HP, Ducoté J, et al. Esophageal hiatal hernia in three exotic felines: Lynx lynx, Puma concolore and
35.
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Panthera leo. J Zoo Wildl Med 2010;41: 90–4. Zedan M, El-Ghazaly M, Fouda A, El-Bayoumi M. Tension gastrothorax: a case report and review of literature. J Pediatr Surg 2008;43:740–3. Zarelli M, Carrillo JD, Soler M, et al. What is your diagnosis? Tension gastrothorax. J Am Vet Med Assoc 2010;236:733–4. Bredal WP, Eggertsdóttir AV, Austefjord O. Acute gastric dilatation in cats: a case series. Acta Vet Scand 1996;37:445–51. Formaggini L, Schmidt K, De Lorenzi D. Gastric dilatation-volvulus associated with diaphragmatic hernia in three cats: clinical presentation, surgical treatment and presumptive aetiology. J Fel Med Surg 2008;10:198–201. Moore PF, Rodriguez-Bertos A, Kass PH. Feline gastrointestinal lymphoma: mucosal architecture, immunophenotype and molecular clonality. Vet Pathol 2011; epub ahead of print. Briscoe KA, Krockenberger M, Beatty JA, et al. Histopathological and immunohistochemical evaluation of 53 cases if feline lymphoplasmacytic enteritis and low-grade alimentary lymphoma. J Comp Pathol 2011;145:187–98. Page CP, Bohnen JM, Fletcher JR, et al. Antimicrobial prophylaxis for surgical wounds. Guidelines for clinical care. Arch Surg 1993;128:79–88. Salinardi BJ, Harkin KR, Bulmer BJ, Roush JK. Comparison of complications of percutaneous endoscopic versus surgically placed gastrostomy tubes in 42 dogs and 52 cats. J Am Anim Hosp Assoc 2006;42: 51–6. Ireland LM, Hohenhaus AE, Broussard JD, Weissman BL. A comparison of owner management and complications in 67 percutanesous esophagostomy and percutaneous endoscopic gastrostomy feeding tubes. J Am Anim Hosp Assoc 2003;39:241–6. Bright RM, Burrows CF. Percutaneous endoscopic tube gastrostomy in dogs. Am J Vet Res 1988;49:629–33. Washabau RJ. Gastrointestinal motility disorders and gastrointestinal prokinetic therapy. Vet Clin Small Anim 2003;33: 1007–28. Nielsen C, Anderson GM. Metastasis of gastric adenocarcinoma to the abdominal wall following placement of a gastrostomy tube in a dog. Can Vet J 2005;46:641–3. Boutilier P, Carr A. Fungal colonization and failure of a long-term gastrostomy tube in a cat. Can Vet J 2005;46:709–10.
28
Stomach Z. Halfacree
This chapter discusses the surgical diseases of the stomach in the cat. Simple gastric surgery, in particular gastrotomy for foreign body removal or full-thickness gastrointestinal biopsy, is sometimes indicated in the cat. More involved gastric surgery, such as gastric resections and pyloroplasty are encountered less frequently. This chapter includes an overview of the preoperative and perioperative considerations for cats undergoing gastric surgery and a summary of the indications for gastric surgery. The surgical techniques for commonly indicated procedures, including gastrotomy and tube gastrostomy, are discussed in detail and the techniques used for pyloric surgery are summarized.
SURGICAL ANATOMY AND PHYSIOLOGY The stomach is positioned in the cranial abdomen at the level of the costal arch, sitting within the concavity of the visceral surface of the liver (Fig. 28-1). The position of the stomach varies depending upon filling and the size of the surrounding viscera. A cat’s stomach can accept 300–350 mL of liquid.1 Ingesta enters the stomach at the cardia, passing through the lower esophageal sphincter. In the cat this sphincter is comprised of an oblique gastric sling muscle, which lies on the left lateral aspect of the sphincter, and a circular muscle that fully encircles the distal esophagus.2 Ingesta exits the stomach via the pylorus; although the exact mechanisms are not clear, it is evident that the pylorus plays an essential role in coordinating gastric motility and gastric emptying.3 The vascular supply of the stomach is derived from the celiac artery, which branches into the hepatic artery, left gastric artery, and splenic artery. The right and left gastric arteries are situated along the lesser curvature and the right and left gastroepiploic arteries situated along the greater curvature of the stomach. A few branches from the splenic artery (short gastric arteries) supply the fundus. The hepatic artery gives rise to the gastroduodenal artery before continuing as the right gastroepiploic artery. In turn, the gastroduodenal artery supplies the cranial pancreaticoduodenal artery, which is responsible for the vascular supply to the proximal duodenum.4 The parasympathetic innervation is supplied by the vagus nerve and its dorsal and ventral vagal trunks that supply branches to the stomach © 2014 Elsevier Ltd DOI: 10.1016/B978-0-7020-4336-9.00028-7
as they pass through the esophageal hiatus. The sympathetic innervation arises from the splanchnic nerves, with the post-ganglionic fibres from the celiacomesenteric ganglion traveling along the branches of the celiac artery. The feline enteric nervous system is composed of two ganglionated plexuses.5 The gastric lymphatic system drains to the gastric, hepatic, or splenic lymph nodes.1 The gastric lymph nodes are located on the lesser curvature of the stomach within the lesser omentum and are inconsistently present.6 The mesenteric structures supporting the stomach are known as the greater and lesser omentum. The greater omentum is composed of parietal and visceral layers and each layer is composed of two peritoneal sheets. A meshwork of blood vessels and lymphatics running within strands of adipose tissue lies between the fine sheets, creating a net-like appearance. The visceral layer of the greater omentum originates at the dorsal abdominal wall in common with the transverse mesocolon and extends caudally, covering the ventrolateral aspect of the small intestines. At the level of the pelvic inlet the omentum is reflected upon itself to form the parietal layer of the greater omentum
Figure 28-1 A computed tomography scan in transverse section of an adult domestic short-haired cat demonstrating the position of the stomach within the concavity of the visceral surface of the liver.
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Figure 28-2 Topographic anatomy in the normal cat: the tips of the forceps are inserted into the epiploic foramen in the craniodorsal abdomen.
Figure 28-3 A needle foreign body in the stomach of a cat. The cat had ingested a needle and thread and the radiopaque needle is clearly visible.
that lays adjacent to the ventrolateral abdominal wall and continues cranially to insert on the greater curvature of the stomach. The stomach sits between the two sheets of the greater omentum and these then converge at the lesser curvature of the stomach to form the lesser omentum. The potential space between the visceral and parietal layers of the omentum is called the omental bursa. Access to this space is gained via the epiploic foramen (Fig. 28-2) in the craniodorsal abdomen, or surgically by gently creating a small opening through the greater omentum, into the omental bursa. The left limb of the pancreas is present between the sheets of the visceral layer of the greater omentum adjacent to the dorsal aspect of the stomach and the spleen is situated between the sheets of the parietal layer of the greater omentum. The portion of greater omentum extending between the greater curvature of the stomach and the spleen is referred to as the gastrosplenic ligament.
DIAGNOSIS AND GENERAL CONSIDERATIONS
Figure 28-4 An ultrasound image demonstrating a mass involving the cardia of the stomach in a 1-year-old domestic short-haired cat. (Courtesy Alison Moores; © Anderson Moores Veterinary Specialists.)
Hematology, serum biochemistry, serum electrolytes, and urinalysis are routinely performed in cats with gastric disease. Gastric ulceration may lead to anemia and serum electrolytes may be deranged in any patient suffering from vomiting. Vomition and loss of chloride, potassium, and acid-rich gastric secretions can lead to hypochloremic hypokalemic metabolic alkalosis; however, acid–base imbalances can be complex and hypovolemia may lead to metabolic acidosis.7
Inflated thoracic radiography, including both lateral projections, is indicated in patients in which neoplasia is suspected to screen for metastatic pulmonary disease. In patients suffering from regurgitation thoracic radiography is advised to identify evidence of aspiration pneumonia.
Diagnostic imaging
Gastroscopy
Plain abdominal radiography can be valuable in diagnosis of intraluminal foreign bodies (Fig. 28-3) and gastric distension. In order to identify gastric mucosal or mural lesions using radiography, contrast studies may be necessary. However, ultrasonography is frequently rewarding for evaluating these lesions (Fig. 28-4) and often eliminates the need for contrast studies of the stomach in these patients. Approximately 30% of normal cats have submucosal fat which appears as a radiolucent line within the gastric wall on radiography;8 it is important to note that this is a normal finding. Studies of gastric motility and gastric emptying often rely upon fluoroscopic contrast studies.9 Nuclear scintigraphy is the gold standard for monitoring of gastric transit times and gastric emptying.10
Gastroscopy can be extremely useful in the management of gastric disease. It provides an unrivalled perspective of the gastric lumen and mucosal surface and may reveal lesions eluding other imaging modalities, which could also be missed on external evaluation of the stomach at laparotomy. Endoscopy allows biopsy samples to be obtained for histopathology, thereby providing prognostic information and aiding surgical planning if appropriate (Fig. 28-5). Unfortunately, the mucosal surface of neoplastic lesions may be necrotic or inflamed and histopathology can be misleading.11 Gastroscopy is also a useful technique to allow retrieval of foreign bodies without the need for surgery. However, the withdrawal of very large or sharp objects through the cardia and esophagus should be avoided.
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Figure 28-5 Two images captured during gastroscopy performed in an 11-year-old domestic short-haired cat with a history of weight loss and vomiting. Cytologic and histopathologic specimens obtained at gastroscopy confirmed a diagnosis of large cell lymphoma.
SURGICAL DISEASES Full thickness gastric biopsy and gastric foreign body removal are the most common reasons for performing gastric surgery in the cat. Other less common indications include surgery for management of gastric outflow disease, neoplasia, and gastroduodendal perforation and addressing gastric dilatation associated with diaphragmatic rupture.
Gastric foreign bodies Gastric foreign bodies are occasionally seen in the cat, but due to the relative dietary discretion of this species they are far less common than in the dog. The most common gastric foreign bodies include trichobezoars (fur balls) and linear foreign bodies, such as a needle and thread (see Fig. 28-3). Foreign bodies may be responsible for vomiting secondary to gastric outflow obstruction, initiation of gastritis or intestinal plication. They may be seen as incidental findings on abdominal radiographs in the absence of clinical signs. Where facilities and expertise permit, endoscopic retrieval of gastric foreign bodies is preferable to surgery unless the nature of the foreign body suggests that damage to the cardia or esophagus may occur during retrieval.
Linear foreign bodies The most common site of anchorage of linear foreign bodies in the cat is under the tongue (Fig. 28-6); however, anchorage at the gastric pylorus is also seen.12 Plication of the duodenum and jejunum occurs as intestinal peristalsis attempts to move the anchored foreign body aborally, resulting in a functional and/or structural intestinal obstruction; however, unlike the dog, secondary intussusception has not been observed.12,13 The radiographic appearance of linear foreign bodies does not conform to the classical picture of dilated loops of small intestine normally associated with intestinal obstruction and could lead to the diagnosis being overlooked. Thorough patient evaluation together with inspection of the abdominal radiographs for bunching of the small intestine, potentially in an abnormal position, and irregular accumulations of small intestinal gas should alert the clinician to the diagnosis. Removal of the linear foreign body requires release of the anchorage point, which is commonly at the base of the tongue or the gastric pylorus. Surgical management should be performed promptly following release at the base of the tongue, since loss of intestinal plication may expose areas of intestinal perforation and allow leakage of intestinal contents. When the anchorage site is at the pylorus a
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Figure 28-6 Lateral thoracic and abdominal radiograph of a 1-year-old female neutered domestic short-haired cat with a cotton thread linear foreign body lodged under the cat’s tongue. A barium study had previously been performed. The small intestines appear bunched in the cranial abdomen with an irregular contrast pattern. Barium has been absorbed by the cotton thread, highlighting the path of the cotton through the thoracic esophagus from the oral cavity to the abdomen (arrows).
combination of gastrotomy and one or more enterotomy incisions may be required. Initially, a gastrotomy is performed in the distal aspect of the gastric body allowing access to the most proximal portion of the foreign body. Gentle traction can be applied to attempt retrieval via the gastrotomy site; however, caution must be exercised to prevent further damage to the mesenteric border of the small intestine. If any resistance is experienced the foreign body must be removed in pieces; the large portion present within the gastric lumen is sectioned from the portion extending into the small intestine allowing the plication effect to be released. The remaining portion of the linear foreign body is removed through additional enterotomy incisions as required and gastrotomy and enterotomy sites are closed routinely. Careful inspection of the mesenteric border of the small intestine is essential to determine if perforation or necrosis of the intestinal wall has occurred. Multiple sites of intestinal resection and anastomosis can be necessary; however, the incidence of intestinal perforation and requirement for intestinal resection anastomosis is far lower in the cat compared to the dog.12,13 It has been theorized that the thinner, less bulky, nature of linear foreign bodies in cats is responsible for a lesser degree of intestinal plication, resulting in a lower morbidity and mortality in this species in comparison to the dog.13 Based upon review of the literature, it is suggested that the probability of septic peritonitis and death secondary to a linear foreign body is approximately half that in a cat in comparison to a dog.12,13 A technique has been described via which linear foreign bodies may be removed through a single enterotomy in the cat.14 The linear foreign body is secured to a red rubber catheter that is inserted into the intestinal lumen and milked towards the anus, together with the intestinal foreign body. Due to the difference in the nature of the foreign bodies they ingest, this technique is unlikely to be applicable to the dog, but it should always be considered in the cat. The authors describe that this technique would be applicable when the anchorage site was within the stomach; however, the catheter would be introduced via the gastrotomy and advanced aborally towards the anus. Conservative management of linear foreign bodies in the cat has been described with successful outcome.15 This involved identifying the anchorage site of the foreign body under the tongue and releasing it, therefore allowing the foreign body to pass. This could be considered if surgical intervention is not possible due to financial constraints; however, due to the risk of gastrointestinal perforation
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the author would advocate surgical management via exploratory laparotomy.
Pyloric stenosis Gastric dysfunction is seen in young, pure bred cats, in particular Siamese cats.16 They are generally less than 6 months old at presentation. The presenting clinical signs include vomiting, which may be projectile, and weight loss; regurgitation may also be present. Investigations reveal gastric distension and a functional delay in gastric outflow associated with pyloric stenosis (Fig. 28-7). Normal gastric emptying should start within 15 minutes of barium ingestion and the stomach is generally empty in four hours.9 Concurrent megaesophagus is often present (Fig. 28-7) and while primary megaesophagus is suspected, it can be unclear if this is due to secondary esophagitis. Postmortem examination of one cat has documented gastric heterotopia, with secretory gastric mucosa within the distended esophagus, presumably contributing to esophagitis.17 Some cats have been successfully managed medically with postural feeding and gastroprotection; however, when delayed gastric emptying or pyloric stenosis are documented, pyloroplasty is warranted. As this appears to be largely a functional obstruction, pyloromyotomy or Y to U pyloroplasty are likely to be sufficient; a Billroth procedure is not warranted. Tube gastrostomy (see Box 28-3) is recommended due to the potential for altered gastric motility following pyloroplasty in a patient where gastric motility may already be abnormal. The outcome is likely to be influenced by presence of megaesophagus, but the prognosis for resolution of megaesophagus is unclear until resolution of vomiting has been achieved, together with an appropriate period of medical management for esophagitis.
Gastroduodenal ulceration and perforation Gastroduodenal ulceration is occasionally seen in the cat.18–21 Predisposing factors include stress associated with surgery, administration of steroid or non-steroidal anti-inflammatory medication, and as a paraneoplastic syndrome (e.g., systemic effects of mast cell neoplasia or pancreatic gastrinoma).18–21 Several cases reported in the literature have failed to identify an underlying cause. Gastric ulceration and perforation may also occur secondary to primary gastric disease, including neoplasia and inflammatory bowel disease. Clinical signs include inappetence, vomiting, hematemesis, and melena; progression to gastric perforation may result in depression and collapse due to sepsis. Anemia is a common clinical finding in cats with gastrointestinal blood loss; however, it is important to note that hematemesis or melena were present in less than a third of cats with gastrointestinal ulceration in one review.18 Cats that have suffered from gastric perforation may present with depression and abdominal distension due to pneumoperitoneum. Radiographic evidence of marked spontaneous pneumoperitoneum in the cat should raise the suspicion of gastric perforation (Fig. 28-8). Ultrasonographic findings of gastric perforation can be quite nonspecific, with bright regional mesenteric fat and peritoneal effusion noted most frequently.22 Abdominal radiography is advocated to facilitate detection of pneumoperitoneum. Tension pneumoperitoneum causing respiratory embarrassment has been described in a cat with concurrent upper respiratory tract obstruction.23 Therapeutic abdominocentesis may be required in this situation to achieve stabilization; however, this is uncommon. Indications for surgery in cats with gastroduodenal ulceration are listed in Box 28-1. Surgery is invariably required as cats tend to present when disease is advanced and gastric perforation has occurred. Septic peritonitis is a life-threatening condition with a guarded prognosis; its presence necessitates careful patient stabilization and prompt surgical intervention (see Chapter 26). In one study looking at septic peritonitis in cats, with a range of underlying causes, only 12 of 26 cats survived to discharge.24 Thorough exploratory laparotomy, gastric resection at the site of perforation (see Box 28-4), copious lavage, and empirical antibiosis (while pending culture results) are
A
B Figure 28-7 Fluoroscopic barium swallowing study in a 6-month-old male neutered Siamese kitten. (A) The esophagus is moderately dilated along its length. (B) The stomach is distended with food particles, fluid and gas. There is no evidence of barium passing into the small intestines after 15 minutes, suggestive of pyloric stenosis.
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Figure 28-8 A lateral abdominal radiograph of a 5-year-old male entire domestic short-haired cat that presented following discovery of small focal penetrating wounds. The cat had been shot with an air rifle and one of the airgun pellets had perforated the gastric wall.
Stomach
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Box 28-1 Indications for surgery in cats with duodenal ulceration Failure to respond to medical management Life-threatening gastrointestinal hemorrhage Evidence of gastric perforation
essential. The site of gastric perforation can be challenging to identify and thorough inspection must be performed. Perforation of a gastric ulcer involving the pylorus can present a surgical challenge. The morbidity associated with a Billroth I (pylorectomy and gastroduodenostomy) or Billroth II (pyloroduodenectomy and gastrojejunostomy) is ideally avoided in patients with potentially benign disease. When possible, local debridement and primary closure should be performed in the first instance, avoiding more radical gastric resection which is potentially unnecessary. It is essential that the repair is augmented with omentum or a serosal patch. Tissue must always be obtained for histopathology to rule out gastric neoplasia. Gastric perforation may be caused by trauma; due to the protected site of the stomach within the costal arch the most common traumatic lesion is a ballistic projectile, such as an airgun pellet (Fig. 28-8).
Disorders associated with the esophageal hiatus Gastric disease associated with the esophageal hiatus occurs infrequently in the cat, with only a few case reports available in the literature.25–28 Gastroesophageal intussusception is the term used to describe invagination of the stomach into the lumen of the distal esophagus. Predisposing factors are reported to be megaesophagus, an incompetent lower esophageal sphincter, and chronic vomiting. Presenting signs include regurgitation, vomiting, dyspnea and collapse. The prognosis is considered guarded, but successful outcome has been reported in the dog following prompt diagnosis and intervention.29 Surgical management involves an exploratory laparotomy, reduction of the intussusception, gastropexy, and placement of a stomach tube. Non-surgical management with endoscopic reduction of the intussusception intraluminally and percutaneous endoscopic gastrostomy tube placement has been reported in one puppy.30 In contrast to the dog, in which gastroesophageal intussusception is predominantly a life-threatening condition requiring rapid intervention, intermittent gastroesophageal intussusception with mild chronic clinical signs represents two of the four individual case reports in the cat.26,28 Congenital sliding hiatal hernia has been reported in a small number of cats.31–33 Surgical management, by herniorrhaphy, esophagopexy and incisional gastropexy is reported,31,32 although there was no long term follow up. Successful management by dietary change, with resolution of regurgitation, has also been reported.33 Surgical management of sliding esophageal hiatal hernia has been reported in a lynx, cougar, and a lion.34 For more information on management of hiatal hernia, see Chapter 45.
Gastric disorders associated with diaphragmatic rupture Traumatic diaphragmatic rupture is frequently encountered in the cat (see Chapter 45) and is associated with herniation of abdominal contents, often including the stomach, into the pleural cavity. Rarely, herniation of the stomach into the pleural cavity can result in the
Figure 28-9 A lateral abdominal radiograph of a 4-year-old domestic short-haired cat that presented with acute collapse and dyspnea. The cat has a traumatic diaphragmatic rupture and herniation of the stomach into the pleural cavity with subsequent development of tension gastrothorax. (Courtesy Victoria Lipscomb.)
life-threatening complication of ‘tension gastrothorax’ (Fig. 28-9). Respiratory compromise occurs due to occupation of the pleural space by the stomach which, depending upon position, can become markedly distended by trapped air.35,36 Emergency decompression of the distended stomach is required via passage of a nasogastric tube or percutaneous gastrocentesis. Following stabilization, surgery to reduce the herniated viscera and repair the diaphragmatic rupture must also be performed. Abdominal viscera, including the stomach, may become incarcerated following diaphragmatic rupture and non-viable tissue must be resected (Fig. 28-10). Gastric dilatation and volvulus occurs rarely in cats and diaphragmatic rupture, with the stomach remaining within the peritoneal cavity, appears to be a predisposing factor.37,38 Successful outcome has been reported following appropriate stabilization and gastric derotation at surgery, following the same management approach as for the dog. Gastropexy is advocated; however, the literature indicates this is not consistently performed when the predisposing factor of diaphragmatic rupture has been identified. Sliding hiatal hernia has been reported as a complication following diaphragmatic rupture and diaphragmatic herniorrhaphy in the cat;33 successful surgical management is reported with hiatal herniorrhaphy and tube or incisional gastropexy.
Gastric neoplasia Gastric neoplasia is uncommon in the cat and is generally seen in older animals. Lymphoma is the most commonly reported gastric tumor in the cat and it is not amenable to surgical resection due to the diffuse nature of disease. In comparison to lymphoma at other sites, a histopathologic diagnosis is often required to achieve a diagnosis in visceral lymphoma.39 Even then, it can be difficult to differentiate low grade lymphoma from lymphoplasmacytic enteritis on the basis of cytology and histopathology and therefore other tests such as clonality may be required.40 Most cats are feline leukemia virus negative. Feline gastric adenocarcinoma is rare and the stomach is the least commonly affected gastrointestinal site in the cat.
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A
B
C
D
Figure 28-10 A chronic traumatic diaphragmatic rupture in an 8-year-old domestic short-haired cat with herniation of the stomach, small intestines and omentum into the pleural cavity. (A) The diaphragmatic defect in the tendinous portion of the diaphragm following reduction of the herniated abdominal contents. (B, C) A section of jejunum and a region of the gastric wall had become strangulated. (D) The portion of devitalized gastric wall was resected and closed in two layers. (Courtesy Matthieu Cariou.)
PREOPERATIVE CONSIDERATIONS Thorough preoperative investigations are essential to attempt to achieve a diagnosis prior to surgery, therefore allowing a surgical plan to be formulated. Adequate preparation can then be made to prepare the cat for surgery, decide on therapeutics and anesthetic needs, and also to consider the postoperative conditions that will be required.
Surgical considerations Despite preoperative investigations, additional findings may be made at surgery and it is important to perform a full systematic abdominal exploration. Evaluation of a gastric mucosal lesion and its extent can be facilitated by inspection through a gastrotomy made opposite the lesion, thereby aiding intraoperative decision making.
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Perioperative antibiotic use Gastric surgery in which the gastric lumen is entered is classified as clean contaminated surgery, provided appropriate care is taken to ensure minimal intraoperative contamination. Perioperative prophylactic antibiosis is therefore appropriate but postoperative antibiotic administration is not justified.41 Minimal intraoperative contamination is achieved by use of stay sutures to manipulate the gastrotomy, use of laparotomy swabs to isolate the gastrotomy site from the rest of the abdomen, designation of both clean and contaminated areas for surgical instruments, and use of copious peritoneal lavage. Septic peritonitis, due to pre-existing gastric perforation or necrosis, necessitates the use of therapeutic antibiosis postoperatively. This will initially be empirical but should be adjusted based upon culture and sensitivity results from bacteriology samples obtained at surgery.
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Box 28-2 Gastrotomy
Figure 28-11 Stay sutures have been placed in the ventral surface of the stomach to aid in atraumatic manipulation and to reduce the risk of spillage of gastric contents following gastrotomy.
Anesthesia considerations Gastric fluid retention may result in regurgitation with the risk of aspiration at the time of induction. It is important to achieve a smooth induction and intubate the patient promptly; stomach tubes and suction apparatus should be made available. Multimodal analgesia should be provided where possible in patients undergoing a laparotomy. Non-steroidal anti-inflammatory medication is contraindicated in patients that may be suffering from gastrointestinal ulceration and in patients that are hypovolemic. Premedication with systemic gastroprotectant medication (cimetidine or ranitidine) may be indicated in cats with a high risk of gastrooesophageal reflux or regurgitation; elevation of the pH of gastric fluid ameliorates the potential effects upon the esophagus or lungs should regurgitation and/or aspiration occur. For further information on anesthesia see Chapter 2.
Isolate the stomach using moistened laparotomy swabs to pack off other abdominal contents. Place stay sutures in the ventral stomach wall using monofilament suture material, full thickness bites and sutures placed 1 cm apart. Make a stab incision at a non-vascular part of the ventral gastric wall into the gastric lumen, using the stay sutures to ‘tent’ the gastric wall (Fig. 28-12). The stomach wall naturally separates into two distinct layers, with the outer layer including the serosa and muscularis and the inner layer including the submucosa and mucosal layer. Extend the incision using Metzenbaum scissors, making a full thickness cut through the gastric wall. Use suction apparatus to aspirate gastric contents and prevent spillage. If indicated, a full thickness gastric biopsy can be obtained at this stage by excising a portion from the edge of the gastrotomy wound using Metzenbaum scissors. The serosa muscularis and the submucosa mucosal layers will naturally separate. It is recommended to tack the two together with a suture to avoid loss of one half of the biopsy sample. Place additional stay sutures at either wound edge to minimize tissue trauma and facilitate manipulation of the gastrotomy. Remove gastric foreign bodies using swab holding forceps or Allis tissue forceps. Any instruments that were used within the gastric lumen should be discarded and if gloves have become contaminated with gastric contents they should be changed. The gastric wall should be closed in two layers. The author uses a simple continuous appositional suture in both the mucosa/submucosa layer and the outer muscularis/ serosa layer. Absorbable monofilament suture (e.g., polydioxanone, poliglecaprone 25) in 1.5 or 2M is appropriate. Chromic catgut is not recommended. Whenever a gastric foreign body is removed ensure that the stomach and the entire gastrointestinal tract are carefully checked for additional foreign bodies.
SURGICAL MANAGEMENT AND TECHNIQUES The surgical approach to the stomach is via a routine ventral midline celiotomy (see Chapter 23), extending cranially to the level of the xiphoid. Removal of falciform fat is recommended to improve visualization. Increased mobilization of the stomach may be achieved by transection of the hepatogastric ligament and the avascular peritoneal reflection. Manipulation of the stomach is facilitated by placement of stay sutures in the ventral aspect of the stomach to reduce tissue trauma and reduce the risk of gastric contents spillage. The stay sutures should be passed full thickness through the gastric wall to engage the submucosa, with a bite 1 cm in length to avoid suture pull through (Fig. 28-11).
Gastrotomy Gastrotomy (Box 28-2) is commonly indicated for foreign body retrieval, inspection of lesions within the gastric lumen and to obtain full thickness biopsies. The principles of gastrostomy that should be applied prior to performing a gastric resection state that a simple gastrotomy is performed at a site that allows initial luminal inspection without interfering with the subsequent surgical plan.
Figure 28-12 Stay sutures are placed prior to performing a gastrostomy. The stay sutures are used for atraumatic manipulation of the stomach.
Gastrostomy Gastrostomy tube placement in the cat has several indications (Box 28-3). The tube can be inserted per endoscopically (see Chapter 12) or by open surgery (Box 28-4). The latter technique is indicated if the cat is having a celiotomy, if there are not facilities for endoscopic tube placement, or the tubes are not of the type that are ideally placed endoscopically. The major advantage of surgically placed gastrostomy tubes in comparison to percutaneous endoscopic gastrostomy tubes is the reduced risk of peritoneal leakage.42
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The patient can be fed orally with the tube in place and, if ongoing enteral nutrition is required, the cat can be discharged with the tube in place, following appropriate client education.43 The gastrostomy tube should not be removed earlier than ten days postoperatively to ensure satisfactory healing resulting in an adhesion between the gastric and body walls, and therefore avoiding intraperitoneal contamination. While early adhesion formation is promoted in surgically placed gastrostomy tubes by suturing the gastric wall to
Box 28-3 Indications for tube gastrostomy
Nutrition
the abdominal wall, the author still does not recommend early removal. Experimental studies in healthy dogs have reported that the risk of peritoneal contamination is low after three days postoperatively due to adequate adhesion formation;44 however, it is unclear how adhesion formation may be affected by debilitation of the patient. The tube is removed by traction and the stoma is left to heal by second intention. The insertion of a trocar into the lumen of the tube to efface the mushroom tip can be useful to facilitate removal. Sedation or general anesthesia is advisable in the cat. Foley catheters are unsuitable for use as gastrostomy tubes, as degradation of the balloon by exposure to gastric acid may cause premature failure and leakage of gastric contents to occur.
Indications Prolonged inappetence or inability to eat To bypass the oral cavity, pharynx or esophagus Contraindications Primary gastric disease Vomiting patient Used with caution in patients with esophageal dysfunction or altered mentation due to risk of aspiration
Gastric resection
Gastric decompression
Pyloric surgery is infrequently indicated in the cat. Pyloroplasty (Fig. 28-17) is indicated for management of congenital pyloric stenosis (Fig. 28-18), which is associated with delayed gastric emptying. Surgical procedures involving the pylorus may be indicated for management of a discrete gastric tumor or for resection of a perforated area of ulceration (Table 28-1).
Surgery involving the pylorus commonly affects pyloric function and gastric motility postoperatively which may cause gastric retention and inappetence. Placement of a tube gastrostomy allows gastric decompression to be achieved and enteral nutrition to be provided where necessary.
Gastric resection (Box 28-5) is rarely indicated in the cat. It may be indicated for excision of a perforated gastric ulcer (Fig. 28-15), excision of a focal neoplastic lesion, or a devitalized region of gastric wall (see Fig. 28-10).
Pyloric surgery
Gastropexy Gastropexy is seldom indicated in the cat. However, it is recommended in cases of gastric dilatation and volvulus, esophageal hiatal hernia and gastrooesophageal intussusception, that are reported rarely. Tube gastropexy is ideal in these patients both to prevent recurrence of dilation and volvulus and provide nutrition.
POSTOPERATIVE CARE Multimodal postoperative analgesia is provided where appropriate, combining a pure (methadone) or partial (buprenorphine) opioid agonist together with a non-steroidal anti-inflammatory drug if
Box 28-4 Tube gastrostomy technique (Fig. 28-13) Choose an appropriate position for the tube gastrostomy between the body of the stomach and the left body wall, approximately one third of the distance from ventral to dorsal along the body wall and just behind the last rib (Fig. 28-14A). Make a stab incision through the body wall with a number 10 or 15 blade. Pass the external end of the mushroom tipped tube through the body wall using Kelly artery forceps (note the tube is not tunneled at all) (Fig. 28-14A,B). Now block the end of the tube to prevent contamination of the surgical field. Place a purse-string suture in the gastric body at the site where the tube will enter, prior to creating the stab incision (Fig. 28-14C). Insert the mushroom tube via the stab incision. The mushroom tip must be folded within the jaws of a pair of artery forceps to achieve this. Once the tube is inserted (Fig. 28-14D), withdraw it until the mushroom abuts the gastric wall and tie the purse-string suture tight. The stomach is then secured to the body wall using four horizontal mattress sutures between the stomach wall and the body wall, placed around the tube in sequence to create a box of sutures (Fig. 28-14E,F). Omentalize the stoma site by wrapping some omentum around the tube and sutures. Secure the tube externally using a finger trap suture. Additional fixation of the tube is essential prior to recovery from anesthesia to prevent inadvertent removal. This can be achieved using a stockinette dressing or bandaging material.
308
Figure 28-13 Diagram summarizing placement of a gastrostomy tube. Only two sutures are shown between the stomach and body wall; usually four would be placed.
Stomach
A
B
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D
E
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Figure 28-14 Surgical placement of a tube gastrostomy in a cat. See Box 27-4 for details of the technique with a description of parts (A) to (F).
A
B
D
E
C
Figure 28-15 Gastric ulceration and perforation in a 5-year-old female neutered Persian cat. (A) Lateral abdominal radiography revealing a pneumoperitoneum. (B) DeBakey forceps indicate the site of gastric perforation on the lesser curvature of the stomach. Local inflammation of the serosal surface is the only apparent abnormality on initial inspection. (C) A full thickness incision is made through the gastric wall adjacent to the lesion to allow inspection of the mucosal surface and evaluate the extent of the lesion. (D, E) A focal area of mucosal erosion is identified on the luminal surface. A focal area of gastric wall with a margin of normal tissue surrounding the ulcer is resected. This will be closed in two layers, as for a standard gastrotomy incision.
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appropriate. Cats that are hypotensive or have evidence of gastrointestinal ulceration should not receive non-steroidal anti-inflammatory drugs. Early enteral nutrition is recommended as soon as the cat has fully recovered from general anesthesia. Intravenous fluid therapy should be continued until normal oral intake of fluid and food is resumed.
dehiscence. Dehiscence of gastrotomy wounds and subsequent septic peritonitis is uncommon; in one study describing the underlying cause of septic peritonitis in cats, none of the cats had developed septic peritonitis due to gastrotomy dehiscence, while five of 26 cats had developed septic peritonitis due to enterotomy dehiscence.25
COMPLICATIONS AND PROGNOSIS Complications associated with gastric surgery include routine surgical complications such as bleeding, wound infection, and wound
Box 28-5 Gastric resection (Fig. 28-16) Perioperative assessment of the gastric mass or lesion, at the time of exploratory laparotomy, is often necessary to establish if resection is feasible. Evaluation of the extent of a focal mass lesion, and feasibility for resection, is often aided by inspection of the mucosal surface of the lesion via a gastrostomy on the opposite side. In some cases (e.g., benign adenomatous polyps), submucosal resection may be appropriate and can be useful for resection of lesions within the pylorus, thereby avoiding more radical surgery. If surgical excision is not straightforward, incisional biopsy of the gastric lesion and regional lymph nodes should be performed to achieve complete surgical staging. Lesions involving the greater curvature may be amenable to resection using surgical stapling equipment (gastrointestinal anastomosis stapler; see Chapter 10). Alternatively, the area that requires resection should be removed using scissors or a scalpel blade. The use of Doyenne bowel clamps, careful use of stay sutures, and a surgical assistant aid the procedure and reduce the risk of gastrointestinal spillage. The stomach should be closed in two layers as for gastrotomy; an additional layer of inverting sutures (e.g., interrupted or continuous Cushing or Lembert sutures) may be used to over-sew the site and reinforce the closure.
A
B
D
E
Figure 28-16 A small lesion can be removed by partial gastrectomy. Closure is achieved by placement of a continuous appositional suture in the two distinct layers of the gastric wall, reinforced by an inverting suture if required.
C
Figure 28-17 A 6-month-old male neutered Siamese kitten undergoing a Y-to-U pyloroplasty. (A) The pyloric region of the stomach appears relatively unremarkable on external examination. (B) A full thickness Y-shaped incision is made over the pylorus with the centre of the Y situated at the pylorus. (C) The luminal surface of the pylorus is inspected. (D) The top portion of the Y created a U-shaped flap, which is advanced aborally to widen the pylorus. (E) The Y-to-U pyloroplasty is complete. (Courtesy Dr Stephen Baines.)
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Table 28-1 Summary of the options for pyloric surgery in the cat Surgical technique
Technique
Indications
Disadvantages
Fredet–Ramstedt pyloromyotomy
Longitudinal incision over the pylorus through the serosa and muscularis layers only, leaving submucosa and mucosa intact
This technique is of limited use
Does not allow inspection of mucosal surface Does not allow full thickness biopsy Improvement in outflow may be short-lived due to narrowing during healing
Heineke Mikulicz Pyloroplasty (HMP)
Full thickness longitudinal incision over the pylorus which is then closed transversely to create widening
Pyloric stenosis
Y-U advancement pyloroplasty (see Fig. 28-18)
A full-thickness Y-shaped incision is made over the pylorus with the leg of the Y oriented towards the duodenum. The created flap is used as an advancement flap creating a U-shaped wound
These are preferable first-line procedures due to simplicity and reduced disruption of pyloric function. Subjectively, the Y-U pyloroplasty creates a greater degree of widening than the HMP and allows greater access to achieve mucosal resection. These techniques may afford limited benefit in patients with severe disease, in particular if muscular hypertrophy is advanced and pylorectomy may therefore be indicated
Pylorectomy and gastroduodenostomy (Billroth I)
End-to-end anastomosis of the distal stomach to the duodenum. Luminal disparity must be corrected and can be achieved by spatulation of the duodenal end or partial closure of the gastrotomy
Severe pyloric stenosis Gastric resection due to neoplasia or severe gastroduodenal ulceration
For neoplastic lesions margins of 1–2 cm should ideally be achieved, but close proximity to the common bile duct and pancreas may preclude this
Partial gastrectomy and gastrojejunostomy (Billroth II)
The distal stomach and proximal duodenum are closed and a side-to-side anastomosis of the jejunum to the diaphragmatic surface of the stomach is created. Surgical stapling equipment can be used Biliary diversion and potentially ligation of the pancreatic duct are also necessary
Gastric resection due to neoplasia or severe gastroduodenal ulceration
Complex surgical procedure resulting in significant long-term postoperative morbidity This technique should be avoided unless all other options have been ruled out Careful client communication regarding morbidity and the need for long-term medical management is essential
A
B
C
Figure 28-18 Y-to-U pyloroplasty for pyloric stenosis. (A) A Y-shaped incision full thickness incision is made just proximal to the pylorus. (B) The first suture, indicated by the arrow, converts the Y to U. (C) Additional sutures are placed to close the gastrotomy.
Comments
Take great care to avoid damage to the common bile duct in its course through the lesser omentum
Surgery involving the esophageal hiatus or the gastric pylorus may interfere with regulation of gastric motility in the postoperative period and therefore patients should be monitored for gastric distension. Occasionally, gastric decompression may be required and is facilitated by prior placement of a tube gastrostomy. Careful monitoring of serum electrolytes is essential if gastric decompression is performed. The feeding of a low fat diet will reduce gastric retention and may ameliorate gastric motility dysfunction.45 Complications of gastrostomy tube placement include peristomal inflammation or infection, premature tube removal, septic peritonitis, and fistula formation after tube removal.42 Stoma site metastasis has been reported associated with gastrostomy tube placement in the human and dog.46 Fungal colonization precipitating tube failure has been reported with long-term use.47
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