Camera and trocar placement for robot-assisted radical and partial nephrectomy: which configuration provides optimal visualization and instrument mobility?

Abstract

Proper camera and trocar placement is critical to the success of minimally invasive procedures. For robot-assisted renal surgery, two basic trocar configurations have been described. The medial approach, using a 30° downward-angled lens mimics a traditional transperitoneal laparoscopic configuration. An alternative configuration, using a 0° or 30° upward-angled lens approach locates the camera laterally, evoking a position sense similar to a retroperitoneal approach. Our objective is to compare the differences between these two standard approaches for robot-assisted renal surgery. After performing a review and analysis of available literature, our group tested both the medial and lateral camera approaches during robotic renal surgery performed in human patients. The medial approach provides a wide field of view, because of the relatively greater distance to the target structures and a horizon line closer to the patient's midline. The lateral configuration offers significantly different visualization. The relative proximity to the target structures and a higher horizon line results in a comparatively restricted field of vision. Instrument mobility is comparable between the two approaches. Meta-analysis of the literature reveals that both approaches provide comparable overall operative times for both radical and partial nephrectomy, though there is a trend towards shorter overall operative times for partial nephrectomy performed through a medial approach. The medial trocar configuration provides a familiar working environment for both surgeon and assistant; the wide-angle view enables enhanced visualization of surrounding structures and tracking of the instruments inserted by the assistant. The lateral approach offers the potential advantage of a closer view of the kidney, but does so at the expense of a significantly restricted field of view. In our experience, a medial trocar configuration offers significant advantages over the lateral trocar configuration, and is, therefore, the standard approach at our high-volume center.

Robot-assisted partial nephrectomy in contemporary practice

“…A 12-mm assistant port is placed in the mid-line in either the upper or lower quadrant, depending on tumor location and surgeon preference. If a fourth robotic arm is used, an additional 8-mm trocar is placed laterally, triangulated between the two other robotic trocars (Cabello et al, 2009; Kavoussi et al, 2011). The robot is docked posterior to the patient.…”

Surgical outcomes of robot‐assisted partial nephrectomy

“…One assistant port is then placed at the midline in one of two locations, depending upon tumour location. If a fourth arm is to be used, the trocar is placed laterally, triangulated between the two other trocars [26,57–61].…”

“…One potential disadvantage of this approach is the distance to the kidney, as this often exceeds the reach of the camera arm's excursion. However, this issue rarely presents difficulty, and is largely offset by the digital zoom offered by current generation robotic systems [59].…”

“…The fourth arm is placed a few centimetres lateral to the umbilicus. Two assistant ports are typically placed [59,62,63].…”

“…Disadvantages include the inability to zoom out to a wide angle, which can increase the technical challenge of bowel mobilization, and can hinder the ability to pass instruments under direct vision. In addition, the assistant must often work on either side of the fourth arm [59].…”