title: Subserosal injection of hyaluronic acid may prevent perforation after endoscopic resection.
abstract: OBJECTIVE
  To investigate the protective effect of subserosal injection of hyaluronic acid (HA) after endoscopic resection (ER) using ex vivo and in vivo studies.
  
  
  METHODS
  As the first examination, technical application of subserosal injection was tested 10 times using resected porcine stomachs. As the second examination, ER was applied to make six mucosal defects per stomach in three live minipigs and thermal damage was given on the proper muscle layer by using hemostatic forceps. Following the thermocoagulation, 1 mL of normal saline and HA, respectively, was injected targeting the subserosal layer in two mucosal defects each and the rest kept no injection as the control. The minipigs were recovered from the anesthesia and kept fasting until euthanasia which was carried out around 24 h after the procedures.
  
  
  RESULTS
  Ex vivo study revealed that complete and partial subserosal injection was possible two (20%) and four (40%) times, respectively. In vivo study revealed that no postoperative perforation occurred at any point of the thermocoagulation. Apparent retention of hyaluronic acid was identified at only two (33%) points where HA was injected.
  
  
  CONCLUSIONS
  This study failed to show preventative effects of subserosal injection of HA on postoperative perforation due to technical faults. However, this concept has a possibility to change strategy of ER with further technical innovation.
authors.affiliation: Keiko Niimi, Mitsuhiro Fujishiro, Shinya Kodashima, Satoshi Ono, Osamu Goto, Nobutake Yamamichi, Kazuhiko Koike, Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Niimi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Fujishiro
authors.forename: Shinya
authors.initials: S
authors.lastname: Kodashima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ono
authors.forename: Osamu
authors.initials: O
authors.lastname: Goto
authors.forename: Nobutake
authors.initials: N
authors.lastname: Yamamichi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike