Removal of an object that has been ingested and then became lodged to cause partial or complete intestinal obstruction is probably the most common indication for intestinal surgery. Many different types of foreign bodies can be ingested by dogs and cats. Young, playful or curious dogs are at risk. A breed predisposition has been established for terrier breeds, spaniels and collies. But also older dogs can start ingesting foreign bodies as part of pica behavior induced by an intestinal tumor, inflammatory bowel disease, chronic kidney disease or Cushing's disease.

An intestinal obstruction may be suspected from the history: missing cloths, destroyed chew toys, opened garbage bins, stealing bait from fish hooks, etc. Clinical signs of obstruction include dehydration, vomiting, anorexia, weight loss, lethargy and sometimes abdominal pain and diarrhea. More proximal obstructions will cause more persistent vomiting, with rapid dehydration and electrolyte losses. Patients with distal foreign bodies show less profuse vomiting, more intestinal fluid and gas sequestration, bacterial overgrowth and a slower decline in overall status. Palpation may reveal abdominal tenderness, a mass (in case of intestinal obstruction by a sizeable object) or clumping of the intestinal loops (in case of a linear foreign body). Dogs with a linear foreign body most often have more severe clinical signs.

Diagnosis is usually confirmed with radiography. Radiopaque objects containing metal, porcelain, bone, or dense rubber are easily diagnosed. To verify the objects' position in the intestine two view radiographs (lateral and ventrodorsal) are required. Non-radiopaque obstructing objects classically demonstrate dilated loops of bowl (unless a very proximal obstruction). In case of a linear foreign body shortening and bunching of the intestines may be seen. Presence of free abdominal air is indicative of perforation. For the diagnosis of esophageal foreign objects oral administration of a positive contrast agent can be required. The best diagnostic method for esophageal foreign bodies is esophagoscopy. For the abdomen, ultrasound has been demonstrated to be more accurate than radiography in diagnosing gastrointestinal foreign bodies. In a study on 16 dogs and cats with foreign bodies only 9 were picked up on radiographs while ultrasound was able to detect all of them.

Immediate surgical intervention is indicated for complete intestinal obstructions or intestinal perforation. For lower or partial obstructions, surgery should be performed within 12 hours of diagnosis, allowing time for correction of fluid, acid-base and electrolyte levels. Most animals can be partially corrected and are good surgical candidates within several hours.

Esophageal foreign bodies commonly lodge at the thoracic inlet, heart base, and caudal esophagus, where extra-esophageal structures limit esophageal dilation. The most common esophageal foreign objects are sewing needles in cats, and bones and dental chews in dogs. Sewing needles were accompanied with perforation in 17%, but still endoscopic removal was possible in 93% and resulted in a 98% survival rate. Orad endoscopic removal of dental chews and bones is not always possible (25–90%), but often it is possible to push the object into the stomach (10–71%) resulting in successful alleviation of the obstruction in 63–100%. When a nylon line is still attached to a fishhook, a catheter can be advanced over the line to try and dislodge the barbs entering the mucosa. When not successful, a combination of surgically cutting the perforated part and endoscopic retrieval of the luminal part can be performed. Surgical removal is indicated when retrieval or advancement of the foreign body fails or when forceps extraction presents a significant risk for laceration of the esophagus or major vessels.

Cervical esophageal bodies are removed through a ventral midline approach. Full thickness resection and end-to-end anastomosis can be performed. Suture lines or areas of questionable viability can be patched with the sternohyoideal muscle. Obstructions at the level of the heart base are approached through a right intercostal thoracotomy. When necessary the azygos vein can be ligated and cut. During full thickness resection and anastomosis care is taken to protect the sympathetic nerve. A paracostal abdominal approach can be used to mobilize omentum and bring this through the diaphragm to patch the esophagus.

Oral intake is delayed for 2–7 days depending on the severity of esophageal damage. Nutritional support should be provided during this time (gastric tube). Prognosis after foreign body removal is generally excellent. Complications include esophagitis, necrosis, dehiscence, leakage, infection, fistulae, diverticula, and stricture formation.

Once through the pylorus, the narrowest lumens are the distal duodenum and proximal jejunum. If an object reaches the colon it will usually be passed within a bowel movement. A large retrospective study on gastrointestinal foreign bodies (n = 208) identified the jejunum as the most common location (29%), followed by stomach (24%), duodenum (24%), ileum (18%) and colon (6%). Dogs with a linear foreign body most often have the foreign body anchored in the stomach and continue into the small intestine.

It is imperative that the entire gastrointestinal tract is inspected for other foreign bodies, linear foreign bodies or perforations. A foreign body may not become completely lodged, but will continue to pass down the tract with difficulty, causing mucosal trauma and compromise as it is slowly squeezed through the bowel. Dogs with a linear foreign body more often experience intestinal necrosis, perforation and peritonitis, require intestinal resection and anastomosis. Assessment of intestinal viability is based on subjective criteria: color, arterial pulsations, peristalsis and bleeding from cut edges.

Gastric foreign bodies are removed through a simple gastrotomy. The size and site of the incision depends on the length of the foreign body and whether it is anchored at the pylorus.

Most foreign bodies in the small intestines can be removed with an enterotomy. If there is evidence of ischemia or impending perforation of the bowel wall, enterectomy and anastomosis may be necessary. Suture lines can be reinforced with serosal or omental patching. Essential instrumentation consists of a Poole suction tip, DeBakey tissue forceps, Balfour self-retaining abdominal retractors, Doyen bowel clamps. Bowels should always be handled gently and drying should be avoided since trauma and desiccation can induce a vagal response leading to postoperative ileus. Avoid using electrocoagulation on the bowel wall: arcuate vessels should be ligated and hemorrhage from transected or incised bowl soon cloths with gentle pressure.

The prognosis is considered excellent when there is no evidence of perforation. If perforation occurred, the prognosis depends on the severity of peritonitis.

References

1.  Gianella P, Pfammatter NS, Burgener A. Oesophageal and gastric endoscopic foreign body removal: complications and follow-up of 102 dogs. J Small Anim Pract. 2009;50(12):649–654.

2.  Hayes G. Gastrointestinal foreign bodies in dogs and cats: a retrospective study of 208 cases. J Small Anim Pract. 2009;50(11):576–583.

3.  Hobday MM, Pachtinger GE, Drobatz KJ, Syring RS. Linear versus non-linear gastrointestinal foreign bodies in 499 dogs: clinical presentation, management and short-term outcome. J Small Anim Pract. 2014;55(11):560–565.

4.  Tyrrell D, Beck C. Survey of the use of radiography vs. ultrasonography in the investigation of gastrointestinal foreign bodies in small animals. Vet Radiol Ultrasound. 2006;47(4):404–408.