title: New methods of magnet-based instrumentation for NOTES.
abstract: BACKGROUND
  Laparoscopic surgery has displaced open surgery as the standard of care for many clinical conditions. NOTES has been described as the next surgical frontier with the objective of incision-free abdominal surgery. The principal challenge of NOTES procedures is the loss of triangulation and instrument rigidity, which is one of the fundamental concepts of laparoscopic surgery. To overcome these problems necessitates the development of new instrumentation. material and methods: We aimed to assess the use of a very simple combination of internal and external magnets that might allow the vigorous multiaxial traction/counter-traction required in NOTES procedures. The magnet retraction system consisted of an external magnetic assembly and either small internal magnets attached by endoscopic clips to the designated tissue (magnet-clip-approach) or an endoscopic grasping forceps in a magnetic deflector roll (magnet-trocar-approach).
  
  
  RESULTS
  We compared both methods regarding precision, time and efficacy by performing transgastric partial uterus resections with better results for the magnet-trocar-approach.
  
  
  CONCLUSIONS
  This proof-of-principle animal study showed that the combination of external and internal magnets generates sufficient coupling forces at clinically relevant abdominal wall thicknesses, making them suitable for use and evaluation in NOTES procedures, and provides the vigorous multiaxial traction/counter-traction required by the lack of additional abdominal trocars.
authors.affiliation: Department of Surgery, University Medical Centre Mannheim, Medical Faculty Mannheim of the University of Heidelberg , Mannheim , Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Magdeburg
authors.forename: Daniel
authors.initials: D
authors.lastname: Hauth
authors.forename: Georg
authors.initials: G
authors.lastname: Kaehler
mesh_terms: D000818:Animals; D004867:Equipment Design; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics; D059346:Magnets; D057605:Natural Orifice Endoscopic Surgery / Q000295:instrumentation / Q000379:methods*; D013552:Swine; D013997:Time Factors; D014599:Uterus / Q000601:surgery*