Masakuni Kobayashi

A double-blind, block-randomized, placebo-controlled trial to identify the chemical assistance effect of mesna submucosal injection for gastric endoscopic submucosal dissection

BACKGROUND Previous animal studies and a pilot clinical trial demonstrated that submucosal injection of a thiol compound called mesna could chemically soften connective tissues and thus facilitate endoscopic submucosal dissection (ESD). OBJECTIVE To evaluate whether mesna injection could reduce procedural times for gastric ESD. DESIGN Double-blind, block-randomized, controlled trial. SETTING University hospital. PATIENTS A total of 101 patients with superficial gastric cancer indicated for ESD were enrolled and randomly assigned to either the mesna or control (saline solution) group. INTERVENTION Traditional ESD was performed with a single bolus injection of mesna or saline solution. MAIN OUTCOME MEASUREMENTS Time for submucosal dissection (TSD). RESULTS En bloc resection was achieved for all lesions in the mesna group (53/53) and 51 of 52 lesions (98.08%) in the control group. TSD was not statistically different between the groups (18.62 ± 13.9 [mean ± SD] minutes for the mesna group and 24.58 ± 24.55 [mean ± SD] minutes for the control group; P = .128), and there were fewer time-consuming cases (times over 30 minutes) in the mesna group compared with controls (7/53 vs 15/52; P = .049). Multivariate regression analysis demonstrated that use of mesna, specimen size, and the presence of fibrous scars were significantly correlated with TSD (P < .05). LIMITATIONS Single-center study. CONCLUSION TSD was not significantly different between the mesna and control injection groups, but multivariate analysis indicated that mesna injection reduced procedural challenges associated with the submucosal dissection. ( CLINICAL TRIAL REGISTRATION NUMBER UMIN000003786.).

Can mechanical balloon dissection be applied to cleave fibrotic submucosal tissues? A pilot study in a porcine model

BACKGROUND AND STUDY AIMS Removal of a lesion containing an ulcer scar is one of the most challenging applications of endoscopic submucosal dissection (ESD). The present study examined whether a novel balloon dissector could cleave fibrotic submucosal tissue beneath ulcer scars. METHODS Six pigs were studied. Endoscopic mucosal resection (EMR) with ligation was performed at 7 or 8 sites in the stomach for each animal; 4 weeks later, 23 sites with a visible scar were selected for submucosal dissection. The procedure involved first creating a submucosal fluid cushion (SFC) by injecting either saline mixed with mesna or pure saline. A slender, compliant balloon with a diameter of 8, 13, or 18 mm was inserted into the SFC. The balloon was unfolded and thrust forward to cleave the fibrotic submucosa over approximately 5 cm. RESULTS Fibrotic submucosa was dissected within 90 seconds in 17 of 23 attempts. Isolating the ulcer scar from the muscularis with the SFC prior to balloon dissection and using a thinner balloon catheter both ensured a better dissection. CONCLUSIONS The fibrotic submucosa underlying post-EMR scars can be dissected with the novel balloon dissector, although the technique is less effective in cases with no sign of lifting.

Technical feasibility of visualizing myenteric plexus using confocal laser endomicroscopy

In preceding studies, we identified that the myenteric plexus (MP) could be visualized with confocal laser endomicroscopy (CLE) by applying neural fluorescent probes lacking clinical safety profiling data from the submucosal side. In this study, we evaluated the technical feasibility of MP visualization using probe‐based CLE (pCLE) from the serosal side with cresyl violet (CV), which has been used clinically for chromoendoscopy.