Small Animal Surgical Emergencies. Группа авторов

4.15 Radiograph demonstrating a needle embedded in the esophageal wall of a dog.

Figure 4.16 (a) Marked soft‐tissue swelling and subcutaneous emphysema commonly affect the head and neck of dogs that are presented following stick penetration injury. (b) Cervical emphysema is evident on this survey radiograph. The cause in this patient was a stick penetration of the pharyngeal or esophageal wall. (c) A 5‐cm long piece of wood (W) is visible within the cervical tissues on this magnetic resonance image. The dog had suffered an oropharyngeal stick penetration injury two days previously.

      Needles

Needles may also lodge in the esophageal wall (Figure 4.15). Endoscopic removal of needles that protrude into the esophageal lumen is readily achievable. Needles that migrate through the esophageal wall to rest in the periesophageal tissues may prove very difficult to locate during surgical exploration. These difficulties are compounded by large body size. Intraoperative fluoroscopy is invaluable in these situations; increasing the chance of successfully finding the needle and limiting the extent of dissection required. Resolution of clinical signs is frequently very rapid. The author does not routinely administer antibacterial agents either in these cases or after retrieval of fishhooks.

Esophageal Stick Injuries

Esophageal puncture may occur as part of an oropharyngeal stick injury. Acutely affected dogs display oral and cervical pain. Marked soft tissue swelling and subcutaneous emphysema are often identified (Figure 4.16a, b), together with drooling of sanguineous saliva. Pharyngeal puncture is very seldom life threatening, even when associated with an underlying track of traumatized tissue, but may evolve into a chronic abscess or discharging sinus [6]. In addition, foreign material is more difficult to surgically locate, once an abscess or suinus has developed, in comparison with exploration of the acute case, even with the assistance of advanced imaging. Esophageal wall breach may lead to a syndrome of descending fasciitis and mediastinitis, which may prove fatal [6]. Endoscopic assessment of esophageal integrity, after foreign body retrieval, may provide a useful complement to other imaging modalities, although hemorrhage and mucosal swelling may impair visualization. Survey radiographs appear to be a sensitive modality with which to identify perforation [6] via the presence of emphysema within the cervical tissues (Figure 4.16b), although this does not distinguish between pharyngeal and esophageal perforation. A careful oral and pharyngeal examination using two long‐bladed, brightly illuminated laryngoscopes may reveal a site of injury. This inspection alone does not rule out additional puncture sites arising from a stick entering the esophageal aditus and perforating the esophageal wall more distally. Endoscopic examination of the esophagus is well suited to further characterize the extent of the patients' injuries. Advanced imaging techniques are also very useful for identifying foreign bodies in the tissues of the neck (Figure 4.16c).

Figure 4.17 A splinter of wood being retrieved during a ventral midline exploration of a dog's neck.

It is not understood why esophageal perforation may foster such a fulminant course. Investigators of descending necrotizing mediastinitis following dental abscess rupture or foreign body impalement injuries in humans speculate on the presence of corridors for infection within tissue planes of the neck [20, 21]. Dogs with this condition require aggressive stabilization followed by early cervical exploration for repair of esophageal perforations, retrieval of foreign material (Figure 4.17), debridement and lavage of the affected tissues, and endoscopic placement of a gastrostomy tube. A ventral midline cervical approach affords good access to the entire cervical esophagus.

5 Gastrointestinal Foreign Bodies

       Amie Koenig and Mandy L. Wallace

       College of Veterinary Medicine, University of Georgia, Athens, GA, USA

Introduction

      Gastrointestinal (GI) foreign bodies are common in dogs and cats; therefore, the need for surgical removal of foreign bodies is frequent in veterinary practice. In a pet insurance company report, $3.4 million in claims related to foreign body ingestion in dogs and cats were made in 2014 [1]. Discrete foreign bodies have been reported in all areas of the GI tract, with reports of the most common location being inconsistent [2–4]. Some authors hypothesize that location of the foreign body at the time of required intervention is correlated with owner awareness of ingestion. Lacking owner awareness, intervention occurs when the foreign body moves into a location that results in clinical signs.

Classification of Foreign Bodies

      GI foreign bodies may be classified by clinical impact, for example, partial or complete obstruction, or by the nature of the foreign body, such as a discrete or linear foreign body. In addition, the foreign body may be classified by the location of the obstruction it creates within the GI tract into high (stomach or proximal duodenum), mid (jejunum), and low (ileocecocolic junction) obstruction and whether it has resulted in perforation.

The possible types of discrete foreign bodies are limited only by one's imagination. Discrete GI foreign bodies that have been reported include magnets, latex teats, wood foreign bodies, (such as skewers or ice pop sticks) sewing needles, batteries, corn cobs, pet toys, children's toys, and solidified wood glue (Figure 5.1) [2,5–10]. Linear foreign bodies may include items such as carpet, clothing, plastic, towel, cloth, thread, and string [11–13]. The type of foreign body is important, as it impacts clinical signs and influences the direction of diagnostics and therapeutic intervention. For instance, discrete foreign bodies, in some cases, can be removed via emesis or endoscopic techniques, while linear foreign bodies that have resulted in clinical signs require surgical intervention.

Pathophysiology

      The underlying pathophysiology of GI foreign body obstruction is the result of failure of forward flow of GI contents secondary to the physical presence of the foreign material. The foreign body has a primary impact on local perfusion at the site of the physical obstruction and a secondary, often more serious, impact on fluid and electrolyte balance and intestinal motility [14, 15]. Proximal to the obstruction, the intestine dilates and distends with secretions and swallowed air. Dehydration results from subsequent vomiting, development of edema of the bowel wall, and loss of absorptive capacity [16]. Metabolic alkalosis results if vomiting is sufficient to result in loss of gastric chloride, potassium, and hydrogen ions or if obstruction sequesters GI contents proximally. Bacterial overgrowth occurs in the static intestinal tract. This overgrowth combined with the compromised bowel wall may lead to bacterial translocation and subsequent bacteremia. As intraluminal pressure increases, venous pressure is exceeded and loss of venous drainage occurs. Loss of arterial flow may occur in severe cases resulting in ischemia and necrosis of the intestinal wall [17]. Additionally, disk batteries can cause tissue necrosis and perforation subsequent