title: Tissue encapsulation of the proximal Essure micro-insert from the uterine cavity following hysteroscopic sterilization.
abstract: OBJECTIVE
  To assess the interaction between the trailing ends of a sterilization micro-insert extending into the uterine cavity and the surrounding uterine tissue environment over time.
  
  
  METHODS
  Multicenter, retrospective observational study (Canadian Task Force classification II-1).
  
  
  METHODS
  Hospital-based clinical research centers.
  
  
  METHODS
  A subset of a study population of 545 women who had undergone a hysteroscopic sterilization procedure.
  
  
  METHODS
  A second-look hysteroscopy was performed in 22 (20 with uterine bleeding, 2 pre IVF) of these 545 women between 4 and 43 months from the sterilization procedure.
  
  
  RESULTS
  Over a mean time period of 19.73 months, the trailing coils of the micro-inserts into the uterine cavity shortened from a mean of 5.7 mm to 2.0 mm and from 5.4 mm to 1.8 mm on the right and left sides, respectively. In cases observed within 12 months or fewer post-procedure, the complete tissue encapsulation of both micro-inserts had already occurred in 17% of the observations. Among cases evaluated from 13 to 43 months post-procedure, 25% evidenced complete encapsulation.
  
  
  CONCLUSIONS
  Two mechanisms appear to be responsible for this process. First, there is an initial mechanical "winding-in" of the micro-insert of approximately 1 rotation of its outer coil, accounting for 1 mm of its length, after release from its delivery system. Second, the tissue around the ostium appears to use the trailing coils of the micro-insert as a scaffolding structure, gradually encapsulating and excluding them from the uterine cavity. The gradual tissue exclusion of the micro-insert from the uterine cavity may make it pregnancy-compatible after in vitro fertilization and embryo transfer procedures.
authors: Flinders Reproductive Medicine, Flinders University and Flinders Medical Centre, South Australia.
authors: John F
authors: JF
authors: Kerin
authors: David
authors: D
authors: Munday
authors: Martin
authors: M
authors: Ritossa
authors: David
authors: D
authors: Rosen
mesh_terms: D000328:Adult; D001672:Biocompatible Materials; D005260:Female; D006801:Humans; D015907:Hysteroscopy; D019736:Prostheses and Implants; D012189:Retrospective Studies; D013246:Sterilization, Tubal / Q000379:methods*
chemical_list: D001672:Biocompatible Materials