Experiment on endoscopic balloon dilation for esophageal stenosis after endoscopic submucosal dissection in pigs.

BACKGROUND AND AIM Endoscopic balloon dilation (EBD) is effective for esophageal stenosis caused by ESD. However, an efficient EBD method has not been established. We, therefore, conducted EBD experiments on porcine esophageal stenosis models. METHODS Study 1: in dilation models (day 22 after ESD), the thickness of the outer muscle layer (as an index of the extension effect) and the area of muscle fiber bundle necrosis in the inner muscle layer (as an index of thermal damage) were evaluated. Study 2: in restenosis models (day 43 after ESD), the thickness of the fibrous plexus (as an index of restenosis) was evaluated. In total, 12 porcine models were created. RESULTS Study 1: the thickness of the outer muscle layer was 1243 ± 322 μm in surrounding locations and it was 803 ± 145 μm beneath the laceration (p = 0.005). In cases of muscular layer injury, the area of necrosis was 15,500 ± 10400 μm2 in surrounding locations and it was 40,200 ± 12900 μm2 at the laceration site (p < 0.001). Study 2: the thickness of the fibrous plexus was 1359 ± 196 μm in surrounding locations and it was 1322 ± 136 μm2 in the laceration scar site (p = 0.74). CONCLUSION Since thermal damage persists until the completion of stenosis, EBD in the initial stage should be carefully performed. An extension effect was observed only at the laceration site and it later returned to a status similar to that of surrounding locations. Additional intervention would be required for preventing restenosis.