Updated: Jan 30, 2019
Oesophageal foreign bodies, particularly those involving pieces of bone, are unfortunately a common reason for presentation of dogs to veterinary clinics.
In the image below, you can see a chest X-ray of a dog, with a bone (encircled) trapped within the oesophagus. This dog presented to me with clinical signs of regurgitation, after having been fed a bone four days prior.
Clinical signs of an oesophageal foreign body include regurgitation, most often shortly after a meal, along with lethargy, reduced appetite, and in more severe cases signs of respiratory distress. The majority of the cases that we see can be managed either with retrieval of the piece of bone by an endoscope, or in some cases where the bone is lodged lower down the oesophagus, advancement into the stomach, also with the aid of the endoscope, can be performed.
In the image below, endoscopy of the same dog demonstrates the bone firmly lodged within the oesophagus, obstructing passage of food.
In cases where endoscopy is not successful, thoracotomy (open chest surgery) is often required.
The major concern regarding bony foreign bodies is the trauma sustained to the oesophageal mucosa, or lining, as seen in the endoscopy image below – apologies for the graphic content. You can see significant bleeding associated with the entire internal surface of the oesophagus, following retrieval of the bone in the image above.
When the trauma is circumferential, in other words involving the full inner diameter of the oesophagus, there is a risk of subsequent oesophageal stricture formation, as seen below. This image shows endoscopy of the same dog, approximately one month following initial presentation. You can see that the oesophageal diameter in the foreground is normal, with abrupt narrowing (oesophageal stricture) further down.
The term 'stricture' essentially implies a narrowing of the inner diameter of a tube-like structure. This stricture formation is simply the result of scar tissue formation, as the oesophageal lining attempts to heal, and cover the defects secondary to trauma from the bone. With any scar tissue, there is significant contraction, which in turn contributes to marked narrowing of the oesophagus.
As I’m sure you can imagine, the more traumatised tissue there is, particularly if it involves the entire internal diameter, the greater the potential for scar tissue, and resultant stricture formation. In addition, although rare, some dogs can present with abnormal free fluid and/or air within their chest. Simply put, this is the result of the sharp ends of the bone tearing or perforating the oesophagus, and leading to escape of either food and/or air into the chest cavity.
In most of these cases, a thoracotomy is required to not only fix the defect in the oesophagus, but also to drain the fluid and/or air, and the prognosis for such cases is guarded to poor.
So why do we care if there is a stricture? Long story short, it affects the consistency of food that can effectively be swallowed and passed into the stomach. With this impact on passage of food, we often see dogs being re-presented with similar clinical signs as that described originally, i.e. regurgitation, because of an accumulation of food in front of the stricture. Not only does this accumulation of food put the dog at risk for worsening oesophageal function of the remaining healthy oesophagus, but most importantly it puts them at an even greater risk for aspiration pneumonia, in other words breathing in the contents of whatever is regurgitated.
Additionally, the section of oesophagus immediately in front of the stricture is often susceptible to oesophageal diverticulum formation. A diverticulum means an outpouching, and this pouch is typically permanent, and in some cases progressively enlarges. The reason behind this progression is that food becoming entrapped within the oesophagus, in front of the stricture, and with more and more food present, it stretches the lining of the oesophagus and makes this pouch. This diverticulum can be another cause for chronic signs of regurgitation, and ultimately requires invasive surgery to correct. Diverticulum formation can also occur while the bone is still in place.
Below you can see a chest X-ray of another dog with an oesophageal foreign body, showing evidence of abnormal free fluid in the chest (later confirmed to be pus), obscuring visualisation of the heart and parts of the lung, along with an oesophageal diverticulum (outpouching) in front of the oesophageal foreign body (bone).
Unfortunately, management of oesophageal strictures can be frustrating in that clinical signs often persist despite various interventions. It can also be costly and not without risk, given that repeated general anaesthetics are generally required as part of the management. Balloon dilatation of the oesophageal stricture is both the most common and most successful technique used.
As the name implies, a balloon-like structure is used (with the aid of an endoscope for correct placement, under general anaesthetic) to dilate and essentially breakdown the scar tissue present, in an attempt to alleviate the stricture/narrowing. It may sound easy enough, however, studies have show that most dogs require at least two treatments, with some requiring even as many as five to eight separate procedures in order to achieve clinical improvement, i.e. less regurgitation, and being able to tolerate more solid consistency food.
That being said, new advancements in this field include the development of a specific feeding tube (placed under general anaesthetic, in the side of the neck), with an overlying sheath that allows for balloon dilatation in an at-home setting. This allows for regular, repeated balloon dilatation without the need for repeated general anaesthetic, however, more research is required to support its benefit over previously favoured management strategies, and at this stage it is not widely available.
In our experience, veterinarians are often criticised for making the recommendation not to feed bones to dogs. Unfortunately, many veterinarians around the world see cases like the ones described here on a regular basis. While feeding your dog a bone may seem harmless, please bear in mind the po