Achieving adequate triangulation is a basic principle of traditional laparoscopic surgery.

Trocars can be directed from multiple points of entry, guiding instruments towards the target organ, where adequate manipulation can be achieved (Fig. 38.1a).

Operating through a single incision with only rigid instruments would be challenging, because the surgeon would either implement a parallel positioning of instruments (Fig. 38.1b) or a ‘crossing’ arrangement (Fig. 38.1c). In the parallel technique, both instruments emerge through the umbilicus; thus, controlling both instruments outside the abdomen would pose a challenge because the surgeon’s hands would be at such close proximity. On the other hand, in the crossing arrangement, there would be a considerably more comfortable range of movement on the outside; however, on the inside, the left hand controls the right instrument, and vice versa, posing a challenge for first-time SLS adopters. As the overall flexibility of the instruments increases, triangulation issues can be overcome without sacrificing external maneuverability.

Flexible instruments have articulating shafts, steering the tip of the instrument toward the target organ and restoring lost triangulation. Thus, combining flexible and rigid instruments has resulted in a more comfortable configuration (Fig. 38.1d, e), increasing maneuverability and the feasibility of advanced surgical procedures using SLS. Recently, curved laparoscopic instruments have been introduced to the field of SLS to restore triangulation and minimize fighting between instruments and laparoscope.

Multiple instruments inserted at close proximity through a common port of entry produce an undesirable limitation of movement both inside and outside. Many advanced procedures involve switching instruments more often, potentially compromising the pneumoperitoneum. These challenges have led to the development of multi-channel ports to avoid the clinching of laparoscopic instruments diverting from a common point.