Success rate of curative endoscopic mucosal resection with circumferential mucosal incision assisted by submucosal injection of sodium hyaluronate. 
Circumferential mucosal incision around a lesion is effective for reliable endoscopic mucosal resection.  However, mucosal incision with a needle knife is difficult, even with submucosal injection of normal saline solution.  To make needle-knife incision easier and safer, sodium hyaluronate has been used rather than normal saline solution.  The aim of this study was to evaluate the clinical outcome of endoscopic mucosal resection with circumferential mucosal incision assisted by submucosal injection of sodium hyaluronate.  For 70 gastric lesions treated by submucosal injection of sodium hyaluronate, the size of the lesion and the resection specimen, the en bloc resection rate, complications, and local recurrence during follow-up were assessed.  The mean size of the lesions and resection specimens were, respectively, 19.9 mm and 30.0 mm.  The en bloc resection rates were 89% (42/47) for lesions up to 20 mm in diameter and 48% (11/23) for those greater than 20 mm (1-20 mm vs. >20 mm, p = 0.0004).  Three patients underwent surgery because of invasive cancer in the EMR specimen.  During follow-up (median 14 months, range 3-38 months), 2 recurrent lesions were found.  No major complication occurred.  Submucosal injection of sodium hyaluronate is a reliable method with a high success rate for en bloc resection of lesions up to 20 mm in diameter.  Mucosal incision with a needle knife can be performed safely with submucosal injection of sodium hyaluronate.