title: The tissue effect of argon-plasma coagulation with prior submucosal injection (Hybrid-APC) versus standard APC: A randomized ex-vivo study.
abstract: BACKGROUND
  Thermal ablation for Barrett's oesophagus has widely been established in gastrointestinal endoscopy during the last decade. The mainly used methods of radiofrequency ablation (RFA) and argon-plasma coagulation (APC) carry a relevant risk of stricture formation of up to 5-15%. Newer ablation techniques that are able to overcome this disadvantage would therefore be desirable. The aim of the present study was to compare the depth of tissue injury of the new method of Hybrid-APC versus standard APC within a randomized study in a porcine oesophagus model.
  
  
  METHODS
  Using a total of eight explanted pig oesophagi, 48 oesophageal areas were ablated either by standard or Hybrid-APC (APC with prior submucosal fluid injection) using power settings of 50 and 70 W. The depth of tissue injury to the oesophageal wall was analysed macroscopically and histopathologically.
  
  
  RESULTS
  Using 50 W, mean coagulation depth was 937 ± 469 µm during standard APC, and 477 ± 271 µm during Hybrid-APC (p = 0.064). Using 70 W, coagulation depth was 1096 ± 320 µm (standard APC) and 468 ± 136 µm (Hybrid-APC; p = 0.003). During all settings, damage to the muscularis mucosae was observed. Using standard APC, damage to the submucosal layer was observed in 4/6 (50 W) and 6/6 cases (70 W). During Hybrid-APC, coagulation of the submucosal layer occurred in 2/6 (50 W) and 1/6 cases (70 W). The proper muscle layer was only damaged during conventional APC (50 W: 1/6; 70 W: 3/6).
  
  
  CONCLUSIONS
  Ex-vivo animal study with limited number of cases.
  
  
  CONCLUSIONS
  Hybrid-APC reduces coagulation depth by half in comparison with standard APC, with no thermal injury to the proper muscle layer. It may therefore lead to a lower rate of stricture formation during clinical application.
authors.affiliation: Department of Internal Medicine II, HSK Hospital, Wiesbaden; teaching hospital of the University Medicine of Mainz, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Manner
authors.affiliation: Erbe Elektromedizin GmbH, Tuebingen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Neugebauer
authors.affiliation: Department of Pathology, University Hospital Tuebingen, Tuebingen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Scharpf
authors.affiliation: Department of Internal Medicine II, HSK Hospital, Wiesbaden; teaching hospital of the University Medicine of Mainz, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Braun
authors.affiliation: Department of Internal Medicine II, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: May
authors.affiliation: Department of Internal Medicine II, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Ell
authors.affiliation: Department of Pathology, University Hospital Tuebingen, Tuebingen, Germany.
authors.forename: Falko
authors.initials: F
authors.lastname: Fend
authors.affiliation: Erbe Elektromedizin GmbH, Tuebingen, Germany.
authors.forename: Markus D
authors.initials: MD
authors.lastname: Enderle
keywords: Argon-plasma coagulation; Hybrid-APC; standard APC; submucosal injection