Diagnostic Imaging Asia Pacific
Safety remains central in endoscopic therapy
CT identifies complications from invasive procedures
By YOSHIE IWASAKI, M.D., SHOICHI KUSANO, M.D., YOSHIKAZU HOSHIKAWA, M.D., AND YASUO NAKAJIMA, M.D.
Endoscopy was originally developed primarily for diagnostic purposes. The introduction of techniques such as polypectomy and endoscopic hemostasis, however, has resulted in an expansion of endoscopic therapy. Technological advances have allowed the less invasive endoscopic approach to become a viable alternative to surgery for a wide range of other gastrointestinal procedures.
Endoscopy is generally considered to be safe and well tolerated. The overall complication rate is relatively low, only slightly higher than that reported for therapeutic procedures. The number and nature of complications may change as instruments become more readily available and use of endoscopy becomes more widespread. Knowledge of possible complications, no matter how infrequently they occur, is essential. It can help ensure prompt diagnosis and proper patient management.
Endoscopic mucosal resection is now an established technique for the curative treatment of mucosal cancers in the esophagus, stomach, and colon. These early-stage lesions, found in part from large population screening programs and efforts to identify high-risk individuals, have been shown to have a low frequency of lymph node metastasis. This allows consideration of less invasive treatment options, thereby improving the quality of life for patients who might otherwise have to undergo surgical resection.
Reported success rates for endoscopic mucosal resection are about 90% with minimal complications.1-3 Perforation and hemorrhage are the most commonly encountered problems (Figure 1). Perforation is likely due to an insufficient volume of saline being injected into submucosa.
The complication rate due to endoscopic polypectomy is relatively low, and these complications are usually seen at the site of polypectomy. Reported occurrence rates range from 0.34% to 2.14% for perforation and from 1.8% to 2.5% for hemorrhage.4 Other rarely reported complications include pneumothorax, pneumomediastinum, retroperitoneal emphysema, retroperitoneal abscess, pneumoscrotum, incarceration of hernia, volvulus, liver injury, and splenic injury (Figure 2).
Endoscopic sphincterotomy consists of an incision in the inferior submucosal papillary sphincter with an electrocautery sphincterotome. The sphincterotome cuts the papillary roof along the course of the intramural duct, making a 10 to 15-mm incision within a defined sector. Reported complication rates of sphincterotomy vary from 2.5% to 11.7%. Complications include hyperamylasemia (22% to 44%), hemorrhage (2.2% to 5%), pancreatitis (2.2% to 3%), cholangitis (0.7% to 5.3%), and stone impaction (0.8%).5-7 Retroperitoneal perforation may occur in 0.5% to 2.1% of cases. Duodenal perforation may occur in 0.5% to 1.4% of cases, with mortality ranging from 0% to 0.4%.
CT is the most accurate modality for evaluating the presence of perforation. Features of perforation on CT include retroperitoneal air dissection, pneumoperitoneum, air collections between duodenum and pancreatic head, localized periduodenal fluid, retroduodenal contrast leakage, and mild swelling of the pancreatic head or of the entire gland. Surgery is often required for localized retroduodenal abscesses, although percutaneous drainage may provide an alternative option (Figure 3).
Endoscopic sclerotherapy remains the cornerstone for both acute and elective management of bleeding esophageal varices.
Most patients undergoing endoscopic sclerotherapy develop ulceration to some degree, which usually signifies mucosal necrosis. In addition to ulceration, other complications associated with sclerotherapy may include erosion, stricture, perforation, fever, chest pain, and pulmonary problems.
The incidence of ulceration has been reported to range from 10% to 78%, and the perforation rate ranges from 1% to 4% in sclerosed patients. Strictures occur in around 20% of cases, although these are usually managed successfully with balloon dilatation.
Intramural hematoma of the esophagus is rare, with a reported incidence of just 0.3% to 1.6% following endoscopic sclerotherapy.8-10
An abnormal coagulation profile and raised portal pressure tend to enhance longitudinal and circumferential expansion, resulting in submucosal dissection. The nature of the intramural hematoma can be defined on either CT or MRI (Figure 4).
Radiologists have an important role to play in endoscopy procedures, both diagnostically and in the prevention, diagnosis, and treatment of complications.
Because a successful outcome in problematic cases can depend on the delay between complication and diagnosis, both endoscopists and radiologists should be alert to the possibility of difficulties. Endoscopy complications can be readily diagnosed and investigated on imaging, then treated with interventional techniques.
DR. IWASAKI is an assistant professor of radiology, and DR. KUSANO is chair of radiology at the National Defense Medical College in Tokorozawa, Japan. DR. HOSHIKAWA is a staff radiologist, and DR. NAKAJIMA is chair of radiology at St. Marianna University School of Medicine in Kawasaki, Japan.
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