Spada C et al. (2005) A novel diagnostic tool for detecting functional patency of the small bowel: the Given patency capsule. Endoscopy 37: 793–800

Delvaux M et al. (2005) Clinical evaluation of the use of the M2A patency capsule system before capsule endoscopy procedure, in patients with known or suspected intestinal stenosis. Endoscopy 37: 801–807

Video capsule endoscopy, commonly used to detect intestinal disease, can be complicated by stenosis that prevents passage of the capsule, often resulting in the need for surgery or endoscopy to remove the device. Prior visualization of strictures in the small bowel is therefore beneficial; however, current techniques, such as small-bowel enteroclysis and small-bowel follow-through, are associated with high doses of radiation and false-negative results. The Given® patency system (Yoqneam, Israel) is a new diagnostic tool developed to detect small-bowel stenosis and consists of two components: a disintegrating capsule with a radiofrequency identification tag and a radiofrequency identification tag scanner. Its detection of strictures is based on the theory that the intact capsule would be unable to pass through a stricture and would therefore disintegrate over time. The efficacy of the capsule has recently been investigated by two different research groups, with conflicting results.

In a feasibility study conducted by Spada and colleagues, the capsules safety and ability to detect strictures was tested in 34 patients with suspected or confirmed intestinal strictures, 30 of whom had Crohn's disease. The capsule was retrieved in the stool of 30 patients; overall, 20 of the capsules remained intact. The capsule was thus unable to detect radiologically ascertained strictures. Adverse events included abdominal pain, which was experienced by six patients one of whom required hospitalization. The capsule was successfully located by the scanner in 94% of the patients. Despite the inability of the capsule to detect strictures, the authors concluded that the device was useful in giving evidence of small-bowel patency and was simple and safe to use.

In the second study, Delvaux and colleagues investigated the use of this system in 22 patients with suspected strictures that required video capsule endoscopy, who had either confirmed or suspected Crohns disease. The capsule was detected by the scanner in 17 of the 22 patients, indicating stenoses; however, the stenoses had been previously detected by CT or small-bowel follow-through in all cases. In addition, symptomatic intestinal occlusion was induced by the capsule in three patients, two of whom required emergency surgery, indicating that the capsule took too long to dissolve.

The authors conclude that the patency capsule is not safe in its present form for use in patients with suspected tight stenoses and is not beneficial to the physician in making the clinical decision to carry out video capsule endoscopy in such patients, as it did not detect stenoses that were not anticipated by existing detection methods. In turn, they highlight the importance of considering a patients clinical history in the selection process for video capsule endoscopy, and suggest a patency capsule that dissolved more quickly following ingestion might be more useful.