Small Animal Laparoscopy and Thoracoscopy

Boel A. Fransson, Philipp D. Mayhew, Boel A. Fransson, Philipp D. Mayhew

• Publisher: Wiley-Blackwell
• Year: 2021
• ISBN:
  9781119666929
• Edition: 2
• Topic: Medicine
• Subtopic: Veterinary Medicine

The newly revised Second Edition of Small Animal Laparoscopy and Thoracoscopy is a rigorous update of the first book to provide comprehensive and current information about minimally invasive surgery in dogs and cats. With a focus on techniques in rigid endoscopy, the book also includes guidance on additional surgeries outside the abdomen and chest. New chapters describe newly developed surgical techniques, while existing chapters have been thoroughly updated.

The authors include detailed stepwise instructions for each procedure, including clinical photographs. Pre-operative considerations, patient positioning, portal placement, and postoperative care are also discussed, with key points of consideration outlined for each surgery.

Purchasers of the book will also receive access to a companion website featuring video clips of the fundamental skills and surgical techniques described in the resource. The book also offers:

• An introduction to laparoscopic suturing and knot tying with accompanying video tutorials
• A thorough introduction to the equipment used in laparoscopic and thoracoscopicveterinary surgeries, including imaging equipment, surgical instrumentation, energy devices, and stapling equipment
• Clear explanations of foundational techniques in laparoscopy, including laparoscopic anesthesia, access techniques, contraindications, complications, and conversion
• Robust descriptions of fundamental techniques in thoracoscopy, including patient positioning, port placement, contraindications, complications, and conversion
• Discussions of a wide variety of laparoscopic and thoracoscopic surgical procedures

Small Animal Laparoscopy and Thoracoscopy is an essential reference for veterinary surgeons, veterinary internal medicine specialists and residents, and small animal general practitioners seeking a one-stop reference for minimally invasive surgery in dogs and cats.

Section IV
Laparoscopic Surgical Procedures

10
Diagnostic Laparoscopy of the Gastrointestinal Tract

J. Brad Case and Penny J. Regier

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Key Points

• Gastrointestinal (GI) exploratory laparoscopy can be performed safely in dogs and cats provided that the minimally invasive surgeon is thorough and possesses good decision‐making ability.
• A complete understanding of GI anatomy and physiology is a mandatory prerequisite before considering a laparoscopic approach to GI disease.
• Accurate preoperative diagnostic evaluation is critical in patient selection for laparoscopic GI surgery.
• Intraoperative alteration of patient position is often necessary for complete evaluation of the GI tract.
• The minimally invasive GI surgeon must be ready and willing to convert to traditional celiotomy if the procedure cannot be completed safely and effectively.

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Preoperative Considerations

Gastroenteric Pathophysiology

A myriad of gastrointestinal (GI) diseases affect dogs and cats, with the most common being obstructive and nonobstructive foreign bodies, infectious, inflammatory, and neoplastic conditions. GI disease disrupts normal physiologic mechanisms and can lead to significant debilitation in dogs and cats, including hypovolemia, hypoproteinemia, electrolyte and acid–base imbalance, inflammation, perforation, and sepsis [1–6]. In the case of obstructive GI disease, acute vomiting can result in fluid and electrolyte losses, but the relative significance to overall fluid and electrolyte balance may be minimal with lower intestinal obstruction [7, 8]. Clinically, however, hypochloremia, metabolic alkalosis, hypokalemia, and hyponatremia appear to be common in both upper and lower GI obstruction [4]. Vomiting is a common sequela to GI obstruction that puts the patient at risk for aspiration pneumonia and further debilitation [8]. Obstructed bowel becomes distended, hypersecretory, malabsorptive, hyper‐ or hypomotile, and ischemic, which can lead to microbial translocation and eventual perforation [1, 2,9–11]. Intraluminal fluid accumulation appears to be significant in the upper GI tract in contrast to the lower intestinal tract, where minimal to no fluid accumulation occurs after acute obstruction for up to 72 hours [2]. Acute small intestinal obstruction also affects electromotor activity of the bowel [10]. A pattern of orad hypermotility results initially, which progresses in an orad direction to the level of the proximal duodenum. Simultaneously, aborad to the obstruction, hypomotility results, which progresses aborad to the level of the terminal ileum [9]. With chronicity, diffuse intestinal ileus eventually ensues [10]. A significant and immediate reduction of intestinal blood flow occurs with intestinal obstruction at intraluminal pressures of 30 mmHg. As intraluminal pressure increases beyond 30 mmHg, a corresponding worsening of intestinal blood flow results until a residual 20–35% of original flow remains [11]. Oxygen extraction by the small intestine also declines as intraluminal pressure increases [11].

Nonobstructive or partially obstructive GI disease in dogs and cats may be associated with a more chronic and subtle onset of signs, including intermittent vomiting, gradual weight loss, mild hypoproteinemia, and hypokalemia [12]. Appropriate recognition and resuscitation of compromised patients before anesthesia and surgery is important regardless of whether or not laparoscopy is to be performed. A laparoscopic approach to GI surgery, when performed safely, should not present any significant additional risks versus a traditional celiotomy. Accordingly, the surgeon and support staff must be trained, experienced, and ready to convert to exploratory celiotomy in both elective and emergent situations if indicated [13–16]. GI laparoscopy is beneficial in staging and determining operability in certain cancers [17] and is associated with minimal morbidity and improved patient recovery compared with more invasive methods in humans [18, 19]. Similarly, in dogs with suspected gastrointestinal obstruction, laparoscopy has been shown to be both feasible and clinically applicable with no major complications and similar minor complication rates compared to exploratory celiotomies [16, 20]. An additional advantage of GI laparoscopy is the reported decreased frequency of adhesion‐related small bowel obstruction postoperatively, which is a common complication in humans after abdominal surgery [21, 22].

Relevant Anatomy

The GI tract in dogs and cats occupies most of the peritoneal cavity and extends from the esophageal hiatus of the diaphragm to the rectum in the pelvic canal. Therefore, complete gastroenteric exploration requires abundant working space and visibility within the majority of the peritoneal cavity. The stomach is divided into four major anatomic regions: the cardia, fundus, body, and pylorus. It is supported in position by surrounding soft tissues, including the esophagus and diaphragm; hepatogastric, hepatoduodenal, and gastrosplenic ligaments; and the liver and mesentery. In diagnostic GI laparoscopy, the ventral parietal gastric surface is readily visible, which facilitates evaluation. In contrast, the dorsal visceral surface is obscured by gravity and the surrounding adjoining soft tissues and thus requires alteration of patient position or gastric manipulation for evaluation in most cases. The pylorus is continuous with the descending duodenum at the cranial duodenal flexure, which is anchored in place by the hepatoduodenal ligament and the mesoduodenum. The descending duodenum originates in the right hypochondriac region and is anchored at the caudal duodenal flexure to the mesocolon [23]. Consequently, laparoscopic evaluation of the stomach and descending duodenum is performed intracorporeally in most cases. The ascending duodenum continues craniosinistrally from the caudal duodenal flexure, where it dives dorsally to the mesentery of the remaining small intestine and transitions into the jejunum. The ascending duodenum and jejunum are only loosely tethered dorsally by a relatively long mesenteric root, which facilitates extracorporeal laparoscopic‐assisted evaluation. At the ileocecocolic junction (ICJ), the mesenteric attachments become shorter and ...