title: Precision in stitches: Radius Surgical System.
abstract: BACKGROUND
  The Radius Surgical System is a manual manipulator with two additional degrees of freedom compared with conventional laparoscopic instruments (CLIs). This study aimed to compare the performance of laparoscopic suturing tasks with the use of the Radius Surgical System and CLIs, respectively.
  
  
  METHODS
  Five experienced laparoscopic surgeons performed laparoscopic surgical tasks in a training box. The tasks consisted of knot-tying, suturing, and needle control tasks. The needle control task was performed to evaluate the precision of the needle drive by analysis of the needle exit point on a suture pad. In the knot-tying and suturing tasks, required time and accuracy value were measured. Needle control tasks were performed on three different angulations of plane. The angles between the instrument plane and the target plane (AIT) were 30 degrees, 60 degrees, and 90 degrees. The distance of the exit point to the center of the target field, the number of actions needed to fulfill a single task, and the required time were recorded and analyzed.
  
  
  RESULTS
  In the knot-tying and frontal suturing tasks, there were no significant differences between the two groups. In the sagittal suturing task, the required time in the Radius group was significantly shorter than in the CLI group. In the needle control tasks on 30 degree and 60 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. There were no significant differences in the number of actions or the required time. In the frontal and sagittal needle control task on 90 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. The number of actions and the required time were significantly less in the Radius group than in the CLI group.
  
  
  CONCLUSIONS
  The two additional degrees of freedom contributed to accurate and controlled needle guidance, especially in difficult spatial situations.
authors.affiliation: Section for Minimally Invasive Surgery, Department of General, Visceral and Transplantation Surgery, University Hospital Tuebingen, Tuebingen, Germany. masahiro.waseda@uni-tuebingen.de
authors.forename: M
authors.initials: M
authors.lastname: Waseda
authors.forename: N
authors.initials: N
authors.lastname: Inaki
authors.forename: J R
authors.initials: JR
authors.lastname: Torres Bermudez
authors.forename: G
authors.initials: G
authors.lastname: Manukyan
authors.forename: I A
authors.initials: IA
authors.lastname: Gacek
authors.forename: M O
authors.initials: MO
authors.lastname: Schurr
authors.forename: M
authors.initials: M
authors.lastname: Braun
authors.forename: G F
authors.initials: GF
authors.lastname: Buess
mesh_terms: D006801:Humans; D020706:Laparoscopes; D010535:Laparoscopy / Q000379:methods; D009339:Needles; D013536:Suture Techniques / Q000295:instrumentation*; D013647:Task Performance and Analysis