title: Natural orifice transgastric endoscopic wedge hepatic resection in an experimental model using an intuitively controlled master and slave transluminal endoscopic robot (MASTER).
abstract: BACKGROUND
  The lack of triangulation of standard endoscopic devices limits the degree of freedom for surgical maneuvers during natural orifice transluminal endoscopic surgery (NOTES). This study explored the feasibility of adapting an intuitively controlled master and slave transluminal endoscopic robot (MASTER) the authors developed to facilitate wedge hepatic resection in NOTES.
  
  
  METHODS
  The MASTER consists of a master controller, a telesurgical workstation, and a slave manipulator that holds two end-effectors: a grasper, and a monopolar electrocautery hook. The master controller is attached to the wrist and fingers of the operator and connected to the manipulator by electrical and wire cables. Movements of the operator are detected and converted into control signals driving the slave manipulator via a tendon-sheath power transmission mechanism allowing nine degrees of freedom. Using this system, wedge hepatic resection was performed through the transgastric route on two female pigs under general anesthesia. Entry into the peritoneal cavity was via a 10-mm incision made on the anterior wall of the stomach by the electrocautery hook. Wedge hepatic resection was performed using the robotic grasper and hook. Hemostasis was achieved with the electrocautery hook. After the procedure, the resected liver tissue was retrieved through the mouth using the grasper.
  
  
  RESULTS
  Using the MASTER, transgastric wedge hepatic resection was successfully performed on two pigs with no laparoscopic assistance. The entire procedure took 9.4 min (range, 8.5-10.2 min), with 7.1 min (range, 6-8.2 min) spent on excision of the liver tissue. The robotics-controlled device was able to grasp, retract, and excise the liver specimen successfully in the desired plane.
  
  
  CONCLUSIONS
  This study demonstrated for the first time that the MASTER could effectively mitigate the technical constraints normally encountered in NOTES procedures. With it, the triangulation of surgical tools and the manipulation of tissue became easy, and wedge hepatic resection could be accomplished successfully without the need for assistance using laparoscopic instruments.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: S J
authors.initials: SJ
authors.lastname: Phee
authors.forename: K Y
authors.initials: KY
authors.lastname: Ho
authors.forename: D
authors.initials: D
authors.lastname: Lomanto
authors.forename: S C
authors.initials: SC
authors.lastname: Low
authors.forename: V A
authors.initials: VA
authors.lastname: Huynh
authors.forename: A P
authors.initials: AP
authors.lastname: Kencana
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.forename: Z L
authors.initials: ZL
authors.lastname: Sun
authors.forename: S C Sydney
authors.initials: SC
authors.lastname: Chung
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006498:Hepatectomy / Q000379:methods*; D057605:Natural Orifice Endoscopic Surgery / Q000295:instrumentation* / Q000379:methods*; D010865:Pilot Projects; D012371:Robotics; D013270:Stomach / Q000601:surgery; D013552:Swine; D014741:Video Recording