"Transmural air leak": a computed tomographic finding following endoscopic submucosal dissection of gastric tumors

A small amount of free air, visible on CT but not on plain chest radiography, which appeared following endoscopic submucosal dissection (ESD) of a gastric neoplasm without endoscopically visible perforation, was defined as a "transmural air leak", and a prospective, consecutive entry study was performed to determine its incidence and clinical significance.

Between January 2006 and September 2008, ESD was performed for 246 gastric lesions in 246 consecutive patients. Abdominal CT scan was performed 1 day after ESD. In addition, chest radiography and blood biochemistry tests were performed at different time points before and after ESD.

Two hundred and nineteen lesions (89 %) were curatively removed by ESD. Among the total of 246 patients, we encountered endoscopically visible perforation during ESD in 2 patients (0.8 %), and clinically suspected perforation diagnosed by the presence of free air on chest radiography but invisible during ESD in 3 patients (1 %), while transmural air leak was observed in another 33 (13 %). Air leak occurred in cases where resection size was larger, procedure time longer, and the muscularis propria on the ulcer base was exposed at the end of ESD. Patients with air leaks developed pyrexia at a higher rate than those without (36 % vs. 16 %, P = 0.018). These patients recovered with antibiotics and required no endoscopic or surgical intervention. The presence of an air leak did not affect the duration of hospital stay.

A transmural air leak was observed in 13 % of the patients undergoing ESD. Larger resection size, prolonged procedure time, and exposure of the muscularis propria on the ulcer base were risk factors for transmural air leak, but the outcome of patients with this complication was good.