Fundamentals of operating on the console

Introduction

Currently available systems for robot-assisted surgery are operator-robot systems that lack operational autonomy. The robotic console is the interface between the surgeon’s hands and the surgical instruments. It is the “cockpit” of the robotic system. The surgical console consists of four main components that are used by the console surgeon: the image interface, the hand controls (surgeon’s), the foot pedals, and the console touchpad. Currently, two different types of surgical consoles are available based on the visualization of the operative field and physical interaction between the surgeon with the console. The closed console systems permit the visualization of the surgical field by looking into the three-dimensional (3D) viewer through a binocular interface, whereas the open consoles use an external 3D monitor and polarized goggles. The former has the advantage of being submerged into the operative field but limits oversight of the operation room and requires microphones for communication with the surgical team.

Improved ergonomics and less physical fatigue for the operating surgeon are considered major advantages of robot-assisted surgery in comparison with open surgery as well as conventional laparoscopy. Despite this, almost one in four robotic surgeons reports physical strain and musculoskeletal discomfort in the head and neck. Therefore the first step at the start of the procedure should be to adjust the console configuration (height of the armrest, height and angle of the viewer, position of the foot pedals) to obtain optimal ergonomics for the surgeon. ^,

When taking a seat at the console, the surgeon needs to have a thorough understanding of the different robot components and master the basic skills of robot-assisted surgery, so he or she can dedicate his or her energy to the challenges of the surgical procedure. Standardized surgical training programs for robot-assisted surgery consist of progressive steps from theoretical courses to, preclinical skills-labs to the modular surgical training. The basic skills a console surgeon needs to master in robotic-assisted surgery include tissue handling and dissection, effective hemostasis, needle handling, suturing and knot tying.

Tissue dissection and handling

Skillful dissection and tissue handling are the trademarks of surgical competence. Smooth dissection along the correct surgical planes will allow the surgeon to progress rapidly while minimizing tissue damage and blood loss. Efficient surgical dissection requires good exposure, dynamic traction, and good hemostasis. Blood will stain the surrounding tissues in red, obscuring the distinctive appearance of different tissues and absorbing the light of the endoscope. In robot-assisted surgery, where the surgeon relies almost exclusively on visual clues, it is of the utmost importance to minimize bleeding during surgical dissection.

Good exposure starts with correct positioning of the patient, making use of gravity to retract the intra-abdominal organs. For example, for pelvic surgery the patient is placed in Trendelenburg position, allowing the bowel to fall out of the pelvis, whereas a reverse Trendelenburg position is used for upper abdominal surgery. The fourth robotic arm can be very helpful for tissue retraction and should be used dynamically to provide optimal exposure ( Fig. 4.1 ).

As the dissection proceeds and the target organ is mobilized, the position of the fourth arm needs to be regularly adjusted to maintain adequate (re)traction. Sometimes it can be useful to place additional traction sutures to improve exposure. A straight needle suture that is passed through the anterior abdominal wall can be used for retracting the peritoneum. Alternatively, traction sutures can be retracted through the assistant port ( Fig. 4.2 ) or with the use of the fourth arm.

Tissue dissection is usually performed with a bipolar robotic grasper in the nondominant hand and the monopolar scissors (or monopolar hook) in the dominant one. The bipolar grasper will provide traction on the tissue while the scissors are used for cold cutting and coagulation. The angle of traction should be away from the target anatomy exposing the connective tissues, often described as the cobwebs, between the different anatomic layers. The robotic grasper can also be used for blunt dissection by pushing the closed tips between the tissue fibers and gently opening them, hereby splitting the tissues along the natural plane of dissection ( Fig. 4.3 ).

In cases where the tissues are diseased because of inflammation, fibrosis, or tumor invasion, the surgical planes may be disrupted, and sharp dissection is needed outside the natural plane of dissection. In these cases, it is important to avoid deep dissection into a narrow space while zooming in with the camera. Zooming out from time to time will help to maintain a good orientation of the operative field and to identify the surgical landmarks.

Different types of robotic instruments, each with their specific shape and grasping force, are available for tissue dissection and retraction. The Prograsp and Cadiere forceps are both nonenergized fenestrated graspers but have distinct grasping forces. The Prograsp has a much higher grasping force than the Cadiere and is mainly used for retraction, whereas the Cadiere can grasp delicate tissues without crushing them, making it ideally suited to manipulate the bowel. Several types of energized fenestrated graspers are available with varying grasping forces that can be used for retraction, dissection, and bipolar coagulation. Curved bipolar dissectors like the Maryland forceps are milled forceps with narrow tips that can be used for meticulous dissection and bipolar coagulation. The choice for any specific grasper depends on the specific needs during the procedure as well as the individual surgeon’s preference.

Suturing and needle handling

The aim of suturing is to accurately approximate the tissue edges to promote the natural wound healing process (e.g., to create a water-tight anastomosis or facilitate primary wound closure). An optimal surgical technique minimizes tissue inflammation by limiting tissue damage and the amount of foreign material (sutures) used. The 3D vision, the use of wristed instruments with increased degrees of freedom, and the superior ergonomics of robot-assisted surgery in comparison with laparoscopy have promoted the use of minimally invasive surgery for complex intracorporeal suturing tasks.

The standard technique for suturing with a curved needle is based on the following steps:

• Grasping the needle with the tip of the needle driver approximately one-third away from the threaded end, while maintaining a perpendicular angle with the axis of the needle.

• Rotating the tip of the needle perpendicular to the target tissue

• Perpendicular penetration of the target tissue

• Rotating the needle driver to allow a smooth trajectory of the needle through the tissue to minimize tissue trauma.

• Releasing the needle when it emerges on the other side of the tissue and grasping at approximately 2 to 3 mm from the tip to complete the curved path through the tissue.

• Repositioning the needle for the next stitch

• Placing the next stitch, making sure to maintain a regular distance between two consecutive stitches and avoid an excessive number of sutures per unit.

The wristed robotic instruments facilitate the circular movement of the needle through the tissues, especially in confined anatomic spaces. Because the surgical operators lack tactile feedback, it can be difficult for a novice surgeon to judge the tension applied to the suture and the encompassed tissues. Excessive tension may result in rupture of the suture, inadvertent tissue trauma, or tissue ischemia. With increasing experience, the console surgeon will rely on subtle visual clues to judge the tension of the suture. Although several tactile force-feedback systems for robot-assisted surgery have been described, none of them have been applied in routine clinical practice so far.

In minimally invasive surgery, it is important to consider the length of the suture to facilitate efficient maneuvers. Too long sutures will result in excessive suture manipulation and the risk of creating accidental knots, whereas too short sutures can make it impossible to tie a knot. The optimal length of the suture depends on the specific task and surgeon’s preference. During suturing, the robotic camera can be used dynamically, zooming in for correct passing of the needle and zooming out for efficiently tightening the stitches. In recent years, barbed sutures have been increasingly used during minimally invasive surgery. These sutures prevent slippage of the stitches and preclude the need for assistance or knot tying, reducing operative time without compromising the quality of the anastomosis.

Knot tying

At the end of the suture, a knot is tied to keep the suture tight. The wristed instruments and 3D image permit the surgeon to tie different types of knots in confined anatomic spaces. To compensate for lack of tactile feedback, the surgeon must pay attention to the response of the suture while it is being pulled to ensure the correct tension. Lack of tension will result in a loose knot, whereas excessive tension can break the suture. When tightening the knot, the position of the needle drivers should be continuously adjusted such that they hold the suture close to the knot. Most sutures are tied with a surgeon’s knot. However, in specific circumstances it is preferable to perform a sliding knot that can be cinched to increase tension on the stitch. This can be achieved by throwing a square knot and converting it into a sliding knot by pulling one end of the suture. After adjusting the tension, the knot is reconverted into a square knot and secured by throwing another half hitch.

Tying a knot can be a time-consuming procedure, and several alternative techniques have been described to lock the suture in place. Barbed sutures can be anchored into the surrounding tissues without need of a knot. Alternatively, plastic clips can be used to quickly secure a suture. This technique is frequently used during robot-assisted partial nephrectomy for the renography with interrupted or running stitches.