title: Trocar-less instrumentation for laparoscopy: magnetic positioning of intra-abdominal camera and retractor.
abstract: OBJECTIVE
  To develop a novel laparoscopic system of moveable instruments that are positioned intra-abdominally and "locked" into place by external permanent magnets placed on the abdomen.
  
  
  BACKGROUND
  In conventional laparoscopy, multiple trocars are required because of the limited degrees of freedom of conventional instrumentation, and the limited working envelope (an inverted cone) created by the fulcrum motion around each port. While robotic systems can improve the number of degrees of freedom, they are restricted by even smaller working envelopes.
  
  
  METHODS
  A collaborative research group from the Department of Urology and the Automation & Robotics Research Institute of the University of Texas, Arlington built a prototype system of magnetically anchored instruments for trocar-less laparoscopy. The only design mandate was that the developed technology be able to pass into the abdomen through one existing 12-mm diameter trocar.
  
  
  RESULTS
  A transabdominal "magnetic anchoring and guidance system" (MAGS) platform was developed to incorporate instruments, retractors, and a controllable intra-abdominal camera. In vitro, the platform was able to anchor 375 and 147 g across porcine tissue 1.8 and 2.5 cm thick, respectively. The permanent magnet platforms were sufficiently strong to retract the porcine liver and securely anchor the camera. Its versatility was demonstrated by moving the camera to virtually any location in the peritoneum with no working envelope restrictions and the subsequent completion of porcine laparoscopic procedures with 2 trocars only.
  
  
  CONCLUSIONS
  Trocar-less laparoscopy using magnetically anchored instruments is feasible and may expand intracorporeal instrument manipulation substantially beyond current-day capability. The ability to reduce the number of trocars necessary for laparoscopic surgery has the potential to revolutionize surgical practice.
authors: Clinical Center for Minimally Invasive Urologic Cancer Treatment, Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9110, USA.
authors: Sangtae
authors: S
authors: Park
authors: Richard A
authors: RA
authors: Bergs
authors: Robert
authors: R
authors: Eberhart
authors: Linda
authors: L
authors: Baker
authors: Raul
authors: R
authors: Fernandez
authors: Jeffrey A
authors: JA
authors: Cadeddu
mesh_terms: D000005:Abdomen; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008280:Magnetics; D008422:Materials Testing