WIRELESS CAPSULE ENDOSCOPY (WCE): LIMITATIONS AND PROBLEMS

Robert Enns, MD,¹ Drew Schembre, MD,² John J Brandabur, MD², Klaus Mergener, MD,²

Division of Gastroenterology, Dept of Medicine, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia¹ and Section of Gastroenterology, Virginia Mason Medical Center, Seattle, Washington, USA²

BACKGROUND: Capsule endoscopy is a novel diagnostic method of imaging the gastrointestinal tract using a wireless capsule which transmits images to a data recorder while the device traverses the small intestine. Although the images are impressive; and the yield appears excellent, there are still technical short-coming that occur during the test.
OBJECTIVE: We reviewed our combined experience with capsule endoscopy to determine the limitations and complications of this device in our patients.
METHODS: Most patients are now prepared for capsule endoscopy with a single bottle of phosphasoda. Following an 8 hour fast, a sensor array system is applied to the abdomen, the capsule is swallowed and the images transmitted to a data recorder worn on the patient's side. Typically, the battery life of the capsule is 8 hours, following which the data recorder is returned, downloaded to a computer workstation and reviewed.
RESULTS: To date, 199 capsule studies have been performed in 180 patients. In 12 studies there was complete/near-complete capsule failure to transmit, 5 capsule had failed spontaneous excretion (2 removed endoscopically, 1 required surgery to remove, 1 found incidentally at surgery), 11 studies had poor visualization (usually food occluding the lumen; in several cases in patients on high-dose narcotics), the capsule became 'lodged' (extended period) with spontaneous passage in 5 cases, significant transmission gaps were seen in 12 studies and in 22 studies the capsule did not reach the cecum prior to end of battery life.
CONCLUSION: Although WCE has a high diagnostic yield for some conditions, both patients and physicians need to be aware of technical problems and other shortfalls.