title: Efficacy of a reverse-phase polymer as a submucosal injection solution for EMR: a comparative study (with video).
abstract: BACKGROUND
  Reverse-phase polymers undergo a temperature-dependent liquid-to-gel transition that may provide a more durable cushion for EMR and could yield improvements in safety and efficacy.
  
  
  OBJECTIVE
  Our purpose was to assess the efficacy of poloxamer solution PS137-25 as a submucosal injection.
  
  
  METHODS
  Comparative study among 3 different solutions for EMR using ex vivo and in vivo porcine models.
  
  
  METHODS
  A total of 120 gastric submucosal cushions were performed in fresh ex vivo porcine stomachs with saline solution 0.9% (n = 40), hydroxypropyl methylcellulose (HPMC) (n = 40), and PS137-25 (n = 40). Five in vivo porcine colon EMRs were then performed.
  
  
  METHODS
  Height and duration of submucosal cushions were measured in the ex vivo model, and the usefulness of reverse-phase polymers was assessed by in vivo en bloc resection.
  
  
  RESULTS
  Ex vivo: The height of mucosal elevation was greater with PS137-25 (10.3 +/- 2.2 mm) than with saline solution (8.3 +/- 2.6 mm) or HPMC (9.05 +/- 2.3 mm, not significant). All submucosal elevations with PS137-25 lasted longer (more than 20 minutes) than with saline solution (20.9 +/- 11 minutes, P < .01) or HPMC (89 +/- 32 minutes, P < .01). After 120 minutes, the elevations obtained with PS137-25 showed no differences in size, shape, or consistency from initial measurements. In vivo: All 5 EMRs were successfully performed after 1 injection of PS137-25. No repeat injections were needed. During resection, a large gel cushion was noted.
  
  
  CONCLUSIONS
  Mucosal elevation with PS137-25 is more durable than with other substances, with no changes in size or consistency observed over 120 minutes. Additionally, reverse-phase polymers performed well in in vivo colon EMRs. These results suggest that reverse-phase polymers may provide increased safety and efficacy for EMR procedures.
authors.affiliation: Hospital Clínic, University of Barcelona, IDIBAPS, CIBEREHD, Barcelona, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Fernández-Esparrach
authors.forename: Sohail N
authors.initials: SN
authors.lastname: Shaikh
authors.forename: Arielle
authors.initials: A
authors.lastname: Cohen
authors.forename: Michele B
authors.initials: MB
authors.lastname: Ryan
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Thompson
mesh_terms: D000818:Animals; D003106:Colon / Q000473:pathology / Q000601:surgery*; D003113:Colonoscopy / Q000379:methods*; D005753:Gastric Mucosa / Q000473:pathology / Q000601:surgery*; D005773:Gastroscopy / Q000379:methods*; D005782:Gels; D065347:Hypromellose Derivatives; D007267:Injections; D007413:Intestinal Mucosa / Q000473:pathology / Q000601:surgery*; D008747:Methylcellulose / Q000031:analogs & derivatives; D020442:Poloxamer / Q000008:administration & dosage*; D012996:Solutions; D013501:Surface-Active Agents; D013552:Swine
chemical_list: D005782:Gels; D012996:Solutions; D013501:Surface-Active Agents; D020442:Poloxamer; D065347:Hypromellose Derivatives; D008747:Methylcellulose