title: Experimental assessment of a new mechanical endoscopic solosurgery system: Endofreeze.
abstract: BACKGROUND
  The assistance received by the surgeon from support personnel during operative laparoscopy is extremely important. This includes retraction of instruments and endoscope positioning. However, human assistance is costly and often does not provide satisfaction for the surgeon. The aim of this study was to develop a mechanical arm capable of allowing easy handling and holding of laparoscopic instruments under the surgeon's control.
  
  
  METHODS
  We designed a system, named Endofreeze, based on a particular kinematical construction that maintains an invariant point of constraint motion just above the trocar puncture site through the abdominal wall. The goal was to develop this way a highly intuitive mechanical holding system for laparoscopic instruments, with sufficient precision of action, activated by a single hand movement. We tested a couple of prototypes with different holding arms while performing cholecystectomy in phantom models with swine inserts and compared the results obtained in similar conditions using different holding and positioning systems.
  
  
  RESULTS
  The system allows transparent and intuitive operation, and its setup is easy and quick. It may be adapted either as an instrument retractor or as an optic positioning device. Compared to different systems available or prototypes previously tested, such as AESOP 2000, ENDOASSIST, FIPS Endoarm, TISKA Endoarm, and the Martin Arm, in similar conditions, it was more intuitive, allowing shorter time for completion of surgery.
  
  
  CONCLUSIONS
  Endofreeze is a new intuitive mechanical positioning system for endoscopic solo surgery. In phantom models, it demonstrated a shorter time requirement for completion of surgery when compared to other systems available. In our opinion, it represents a valid compromise between human and robotic control for conventional laparoscopic instruments.
authors.affiliation: Chirurgia Generale, Ospedale Evangelico Internazionale, cso Solferino 1A, 16122 Genova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Arezzo
authors.forename: M O
authors.initials: MO
authors.lastname: Schurr
authors.forename: A
authors.initials: A
authors.lastname: Braun
authors.forename: G F
authors.initials: GF
authors.lastname: Buess
mesh_terms: D000818:Animals; D017081:Cholecystectomy, Laparoscopic; D019723:Endoscopes; D004724:Endoscopy; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D020706:Laparoscopes; D008348:Manikins; D012371:Robotics / Q000295:instrumentation*; D013523:Surgical Equipment; D034421:Sus scrofa; D013997:Time Factors