Geometry of laparoscopic suturing and knotting techniques

Background: Spatial limitation, together with a fixed trocar position, rest ricted handling, and movement of the instruments, is inevitably associated with reconstructive laparoscopy and retroperitoneoscopy. This problem inclu des not only suturing technique and instruments but also geometric factors of endoscopic reconstruction, such as optimal distances between the working trocars, length of instruments, and angles between the instruments and the object. We present an experimental access to determine the specific impact of these factors on reconstructive laparoscopy. Materials and Methods: In an in vitro model, end-to-end anastomoses of porc ine intestine were performed using a standardized intracorporeal suturing t echnique. Suturing was performed without and after training in reconstructi ve surgery with variation of the following geometric factors: (1) the dista nce between the working trocars (between 6 and 12 cm); (2) the position of the object (lateral right, medially, lateral left); (3) the camera position (medially, lateral right, lateral left); (4) the angle between the instrum ents and a horizontal line (15 degrees, 55 degrees, 90 degrees); (5) the in tracorporeal length of instruments (between 10 and 25 cm); and (6) narrowed space available for the instruments (between 4 and 25 cm). Results: Continual training decreased the time required for suturing betwee n 30% to 50%. Training decreased the time required for nonsuturing activiti es between 50% and 70% but the time required for suturing activities only b etween 20% and 45%. If the space between instruments and camera was limited , shifting the camera into a lateral position simplified the procedure of i ntracorporeal suturing. Angles of <55 degrees between instruments and the h orizontal line simplified laparoscopic suturing, as did angles of <45 degre es between the instruments. In cases of maximally narrowed space (diameter of 4 cm), a suture filament length of <10 cm decreased the time required by 30%. Conclusion: We suggest an isosceles triangle between the instruments with a n angle between 25 degrees and 45 degrees and an angle of <55 degrees betwe en the instruments and the horizontal line as the optimal geometry for intr acorporeal suturing, These data should be considered when planning a recons tructive laparoscopic procedure (i.e., alignment of trocars, table position ). However, further studies are required to confirm these preliminary resul ts.