The lodgment of foreign bodies in the oesophagus is a relatively common cause of referral to veterinary institutions and can represent significant management challenges. Each year, a large number of cases are seen in dogs at Langford, although it is a rare problem in cats. This may be because of their more fastidious dietary habits.

The type of foreign bodies encountered can be considered in two principal groups: bulky foreign bodies, typically pieces of bone/cartilage given as food, and fishhooks. There are smaller numbers of other items encountered less commonly (e.g., sewing needles, razor blades, apple cores, sticks, toys). The distinction into these two broad classes is useful because the consequences and optimal treatment methods appear to be different for the two classes.

Fishhooks are encountered usually in medium to larger breeds, usually after exercise near water. The typical scenario is that the dog is attracted to a piece of discarded bait, in which the hook is seated, and swallows it. The owner may observe the process or find the fishing line protruding from the dog's mouth. The degree of discomfort the dog displays is usually minimal. Fishhooks become lodged in various sites in the oesophagus, although the proximal oesophagus (cricopharynx) and distal oesophagus (gastro-oesophageal junction) are commonly affected.

Bulky foreign bodies, such as cartilage or bone, are more commonly encountered in terrier breeds, although they also occur in larger dogs. Typically, these are table scraps or kitchen waste that the dog has either been given to chew or that the dog has scavenged. Often the incident is not observed by the owner although the dog may be seen to rapidly swallow the object whole when approached. Typically the owner immediately recognises that the dog is uncomfortable, with evident neck or thoracic pain, and making frequent retching or swallowing movements. Many dogs also show ptyalism. Most dogs will show a diminishing discomfort within a few hours and often remain keen to eat or drink, although regurgitation is a common consequence. Aspiration pneumonia is a possible sequel and coughing, pyrexia and dyspnoea may all develop. Occasionally, oesophageal perforation leads to pyothorax, a rapidly declining clinical status and death if not recognised. Although bulky oesophageal foreign bodies (OFBs) may lodge throughout the oesophagus, by far the commonest location is in the caudal thorax, immediately cranial to the diaphragm. Other recognised sites of obstruction are at the thoracic inlet and over the heart base.

Often the history and clinical signs are highly suggestive of an OFB, although regurgitation may be mistaken by the owner or veterinary surgeon for vomiting. However, a high index of suspicion should be maintained for this disease, especially in terriers presented with apparent sudden-onset vomition. Nurses should be aware of this when offering telephone advice to owners, particularly when discussing apparent 'dietary indiscretion' as a cause of vomiting. Clinical findings are unlikely to be diagnostic, unless a fishing line is immediately visible, but good-quality plain radiographs are usually sufficient to make the diagnosis. Since most bulky OFBs lodge in the distal thoracic oesophagus, thoracic films are most useful, and they also allow assessment for aspiration pneumonia and pyothorax. In the majority of cases, a lateral projection is most useful. Fishhooks are usually immediately apparent radiographically, because of their high contrast. Bulky OFBs are variable in radiodensity and many present simply as an ill defined soft tissue density in the caudal thorax. Although plain films are usually sufficient, occasionally a barium study is used to confirm the diagnosis, with the barium clinging to and outlining a filling defect in the oesophagus. This is not a sensitive method for identifying perforation, however.

Typically dogs with oesophageal fishhooks are systemically well and can be treated rapidly if wished. It is not advisable to cut or pull the line at the mouth: it can be a useful aid to removal and should be retained, perhaps by tying to the dog's collar. This advice can be usefully passed to the owner of an affected animal at the time of first contact with the practice. Options to aid in removal are: flexible endoscopy, rigid endoscopy, fluoroscopy, surgery or a combination of these. Fishhooks present in the pharynx/proximal oesophagus can be challenging since the area is difficult to explore surgically and cannot be distended effectively for flexible endoscopy. For these, the author usually tries to dislodge the hook using a disgorger (available from angling shops), which feeds down the line and loops on to the stem of the hook, or blindly with forceps. Practices should keep this valuable piece of non-veterinary hardware available! For more distal fishhooks, flexible endoscopy is generally effective, although a robust pair of grasping forceps is required. The hook is grasped and pushed distally to disengage it from the mucosa. At this stage the point is facing cranially and to remove it from the dog, the hook must be released, usually in the space of the stomach lumen, and re-grasped so the curve is cranial, before the hook is finally retrieved. Although most hooks can be retrieved in this fashion, small hooks, hooks with barbs, triple hooks and those at the gastro-oesophageal junction may prove impossible to dislodge. In those cases, surgery may be required (oesophagotomy). Other clinicians have success retrieving these hooks under fluoroscopic guidance, either with grasping forceps or by threading a rigid tube over the line and then pushing the tube into the curve of the hook to dislodge it before pulling it into the mouth of the tube for retrieval. If non-surgical retrieval is successful, then minimal aftercare is required. Soft food is advisable for a few days but no medication is required.

Bulky OFBs can also be managed with rigid endoscopy, fluoroscopy or surgery. Flexible endoscopy alone is less frequently effective than any of these methods since the endoscopic grasping forceps cannot readily hold the object and since disengaging it from the mucosa is difficult with this technique. However, these dogs are often dehydrated or have aspiration pneumonia. Although removal of the OFB is still considered an emergency, attention must be made to patient stabilisation with fluid therapy and possibly antibacterial therapy before anaesthesia. The author's choice of removal technique is to use large grasping forceps under fluoroscopic guidance. The success rate with this is round 85%, similar to that for rigid endoscopy. Both techniques require some practice and do not simply consist of grabbing and pulling the object! It is critical to appreciate that the OFB is usually embedded in areas of ulcerated mucosa and must be dislodged before retrieval. With the fluoroscopic method, this is achieved by using the closed tips of the forceps to lift the mucosa away from the OFB circumferentially before grasping it. Some twisting is also used but with great caution. Once the OFB is mobile, it can be either advanced into the stomach or retrieved through the mouth. If rigid endoscopy is used, a large-bore hollow endoscope is required. These are not readily available commercially but may be improvised with a large bore tube (e.g., plastic plumbing pipe, 5 cm diameter) and light source (the flexible scope passed alongside is ideal). The tube is pushed down to the OFB, distending the oesophagus and lifting the mucosa away from it. Large grasping forceps are then used to pull the object into the end of the scope and either advance it into the stomach or retrieve it from the mouth. Bones or cartilage advanced into the stomach will be digested rapidly and do not require gastrotomy. If endoscopy is carried out after removal, the oesophageal mucosa will appear severely traumatised but this is an insensitive test for perforation: it is better to repeat thoracaic radiographs after removal to search for pneumomediastinum as an indicator of perforation. If retrieval is uncomplicated, aftercare consists of feeding a soft food for 2 weeks and management of aspiration pneumonia (systemic antibiotics, fluid therapy, nebulisation, physiotherapy). There is no evidence to support the use of mucosal protectants or antibiotics for oesophageal ulceration, although this is often done. The prognosis for dogs after uncomplicated retrieval is excellent.

When OFBs cannot be retrieved by endoscopic or fluoroscopic means, oesophagotomy is required. Most authors consider that this should only be undertaken when non-surgical retrieval has failed and this is supported by experience suggesting a significant morbidity and mortality (up to 30%) after transthoracic oesophagotomy (TTO). TTO is an involved procedure because of the surgical technique itself, the traumatised condition of the oesophagus, the anaesthetic complications and the aftercare required. The surgical approach is a lateral thoracotomy at the level of the OFB. Most OFBs are in the caudal thorax and either a right-or left-sided approach at around the eighth intercostal space is used (the position is determined from preoperative radiographs). The author chooses a left-sided approach and carries out a left flank laparotomy after removal to place a feeding gastrotomy tube. Before the chest is closed, the pleural space is lavaged copiously and a chest drain placed. A gastrotomy tube for postoperative feeding is indicated and the author prefers to do this via a laparotomy rather than risking further oesophageal trauma through endoscopic placement.

Postoperative aftercare is demanding, with attention required to analgesia, chest drain care and feeding in particular. The animal is kept nil per os for several days at least, with fluids provided intravenously initially. Tube feeding is started 24 hours after surgery. A significant proportion of animals do not survive the first 48 hours, usually because of overwhelming sepsis or pleural effusion. Close monitoring is required, not only in the first few hours after thoracotomy but also in the next few days because of the high incidence of life-threatening complications. Overall, the level of nursing required for these dogs is intensive and relatively advanced. In the longer term, there is a significant incidence of oesophageal stricture formation.

References

1.  Hotston Moore A. Removal of oesophageal foreign bodies in dogs: use of the fluoroscopic method and outcome. Journal of Small Animal Practice 2001; 42: 227-230.