Esophageal Balloon Dilatation & Esophageal Stenting
Esophageal strictures can be secondary to inflammatory conditions, such as reflex esophagitis (commonly postanesthesia), caustic substance ingestion, complications from medications (eg, doxycycline tablets) coming into contact with esophageal mucosa for a prolonged time, esophageal foreign bodies, congenital anomalies, and esophageal neoplasia (space-occupying lesion). Stricture recurrence after routine endoscopic-guided balloon dilatation is common.
Fluoroscopy–endoscopy together assist in balloon dilatation of esophageal strictures in humans, thereby improving visualization when breaking up the stricture.
Esophageal stenting should be reserved for when balloon dilatation alone fails, as it is associated with multiple complications, including discomfort with persistent esophageal distention, stent migration, proliferative tissue ingrowth around the stent ends, or stricture in-growth through the stent. Permanent stenting for benign disease is, therefore, not ideal in the esophagus. Pliable stents with a peristalsis-friendly shape (ie, dumbbell and self-expanding stents) can be placed, but irritation and high migration rates are still risks. Stents are, however, well tolerated for nonresectable esophageal malignancies.
Tracheal Collapse: Extraluminal Rings & Tracheal Stents
Esophageal/Naso/Gastro–Jejunal Feeding Tubes
In humans, enteral methods of feeding are preferred over parenteral because of the lower complication rates and the benefits on gut mucosal integrity and barrier function. Although it is controversial in veterinary patients, jejunal feeding may be preferred in patients that are unconscious, have regurgitation–reflux concerns (eg, mechanically ventilated patients), have pyloric outflow obstructions, are intolerant of gastric feeding or show intractable vomiting, or when pancreatic exocrine duct bypass is desired because of pancreatitis.
Although jejunal feeding has classically involved surgical or laparoscopic assistance, endoscopically placed percutaneous endoscopic gastrostomy (PEG)-jejunal feeding tubes and fluoroscopically placed nasojejunal feeding tubes have been investigated. Tubes can be placed into the jejunum through the nares or esophagus using fluoroscopy with or without endoscopy, eliminating enterotomy or gastrostomy complications. In addition, endoscopic wire placement across the pylorus during an upper GI endoscopic procedure can be fast, effective, and relatively inexpensive (compared with surgical placement) and can remain in place for more than 2 weeks.
Colonic Stenting
Although rare in small animals, colonic obstructions may occur secondary to neoplasms, strictures, or granulomatous lesions. Colonic stents (vs strictures) are most commonly used to treat neoplasms in human patients at high surgical risk or with low likelihood of surgical cure. In addition, colonic stenting has been used as a mechanism for bowel preparation before resection and anastomosis when deobstipation is necessary; clinical success has been seen in up to 95% of human patients.
Figure 3. Lateral radiograph of a feline patient after a colorectal stent was placed for colonic stricture