Fig. 34.1
The azimuth angle
The elevation angle reflects the optimal elevation angle between the instrument and the horizontal plane and has to be 60° (Fig. 34.2).
Fig. 34.2
The elevation angle
The manipulation angle reflects the best ergonomic layout for laparoscopic surgery which is in a range from 45° to 75° between the instruments with equal azimuth angles [7, 8] (Fig. 34.3).
Fig. 34.3
The manipulation angle
Once obtained, the triangulation allows one to reach the target surgical field correctly, and the ergonomics and accuracy are a function of the length of the lever arms with an optimal ratio between internal and external length of the instruments.
In SILS, there is only one port with the loss of all the correct angles described above. Fixed direction and fulcrum force the parallelism of the instruments: the lateral movements can only be achieved by an inversion of instruments; the tool that comes from the right side can only pull on the left and vice versa. Therefore, the traction is inverted compared to the movement of the hands.
The loss of triangulation results in less accurate manoeuvres. The inversion of the hands causes external crossing of instruments and hands with a consequent internal “sword fighting” and left/right inversion of direction [3, 9].
By using curved, articulated or instruments of different lengths and flexible scopes, we can reduce incidents, but it does not avoid this issue.
For these reasons, SILS is still a demanding technique with manoeuvres that are not easy to do and sometimes inaccurate.
Robotic Assisted SILS
A robotic platform appears to be particularly suitable to overcome some of these limitations with technological advantages such as stable 3D views, tremor filtration, precise and delicate movements, and software that automatically associate the surgeon’s hands to the ipsilateral instrument tips to restore intuitive control. First attempts were made using traditional robotic EndoWrist® instruments and homemade or laparoscopic monoport.
The most frequently used was the GelPort/GelPOINT™ (Applied Medical, Rancho Santa Margarita, California, USA) with the possibility of introducing the instruments in more lateral position to reduce external conflict [10, 11]. The robotic software assigns each instrument to the contralateral hand in order to offset their crossing inside the abdomen. The triangulation achieved only by the articulated tips of EndoWrist® is only a few centimetres, whereby the internal and external conflicts of the instruments are not yet resolved. In addition, the force of the robotic arms can displace the port from its seat causing loss of pneumoperitoneum.
The Single-Site™ Platform
The recent new Single-Site Robotic Platform (da Vinci Surgical System, Intuitive Surgical Inc., Sunnyvale, CA) allows one to overcome the issues previously described [12].
The main features of this platform are the use of instruments with flexible shafts, rigid curved cannulae that cross at level of the abdominal wall (remote centre) and restoration of the correct hand/instrument correlation achieved by reassigning control of the instrument arms (Fig. 34.4a, b).
Fig. 34.4
(a, b) The flexible instruments are introduced through the curved cannulae. The remote centre is at the level of the abdominal wall into the port
The curvature of the cannulae, crossing inside a dedicate port, increases the distance between the instruments tips allowing each to reach the target anatomy in a convergent way, from the opposite side to the side of introduction, restoring the correct triangulation. The shape of the curved cannulae, externally, keeps the da Vinci arms separated to avoid external collisions and instrument crowding. The intra-abdominal instrument position is reversed: the instrument that enters the abdomen from the left reaches the operative field on the right and vice versa. The da Vinci software automatically reassigns the surgeon’s hands to the ipsilateral instrument tips restoring the intuitive control.
Keeping the remote centre at the level of the abdominal wall and the curvature of the cannulae with consequent convergence of the instruments ensures that there is an optimal focal distance of work allowing the instruments to converge correctly on the anatomical target (Fig. 34.5).
Fig. 34.5
The optimal focal distance of work allows the instruments to converge correctly on the anatomical target
If the target is closer or further away with respect to the optimum focus, it will be necessary to advance or retract the cannulae causing an incorrect positioning of the remote centre.
These modifications could cause excessive stress on the port and on the abdominal wall resulting in improper working of the instruments and loss of CO2. Moreover, if the instruments come out too far from the cannulae to reach a distant target, more of the flexible shaft extends beyond the rigid support of the curved cannulae and loses traction strength. The availability of two sets of robotic curved cannulae of different lengths mitigates this issue.
The single-site platform was primarily designed to work in a narrow operative field and with a discrete anatomical target such as during a cholecystectomy; however, recently it has also been used for colonic surgery.
Instruments and Accessories
Single-Site™ Port
The Single-Site™ port is made of silicone and has a target anatomy arrow indicator and five lumens (Fig. 34.6).
Fig. 34.6
The Single-Site™ port
Three of these are straight: for the scope, for the insufflation adaptor and for assistant instruments. The two more lateral lumens are curved and cross in the midline of the monoport with the outlet holes on the opposite side of entry. The curved robotic cannulae are inserted into these channels.
Single-Site™ Accessories
5 × 300-mm curved cannula “1”
5 × 300-mm curved cannula “2”
5 × 300-mm flexible blunt obturator
5 × 250-mm curved cannula “1”
5 × 250-mm curved cannula “2”
5 × 250-mm flexible blunt obturator
5-mm straight accessory cannula
10-mm straight accessory cannula
10-mm straight blunt obturator
Dock Assist Tool
8.5-mm endoscope cannula
8-mm blunt obturator
5-mm blunt obturator
Intuitive surgical 30° 8.5-mm endoscope
Intuitive surgical 0° 8.5-mm endoscope
Robotic Flexible Instruments
Maryland dissector
Crocodile grasper
Fundus grasper
Cadiere forceps
Curved scissors
Monopolar cautery hook
Hem–o–Lok ® clip applier
Hem-o-Lok ML clips
Suction irrigator
Needle driver
All of the Single-Site™ instruments are flexible in order to allow introduction into the curved cannulae and rotate on their own axis at 360°. The flexibility, however, does not allow, in the current version, the possibility of having EndoWrist® technology, as in traditional robotic instruments.
In this chapter, we described the techniques of robotic Single-Site™ cholecystectomy (SSRC) and robotic Single-Site™ right colectomy.
SSRC Procedure Overview
The patient is placed in a supine position with both arms tucked away as required. The patient cart should approach the patient 45° (from perpendicular) over the right shoulder (Fig. 34.7) ensuring that the target anatomy is in line with the centre column, umbilicus and arrow on the port. Only three robotic arms are used: arms 1, 2 and camera arm. Robotic arm 1 is placed to the left of the patient, and its instruments reach the surgical field from the right (i.e. from the lateral side of the gallbladder); robotic arm 2 is placed to the right of the patient, and its instruments reach the surgical field from the left (i.e. from the medial side of the gallbladder). The camera arm is in line with the centre of the column bent at an angle of 45° (sweet spot). The assistant surgeon is to the left of the patient, and the scrub nurse is positioned at the patient’s feet. The main assistant monitor is located at the patient’s right within view of the assistant (Fig. 34.8).
Fig. 34.7
Patient chart set-up
Fig. 34.8
O.R. set-up for Single-Site™ cholecystectomy
Using standard surgical techniques, a 2.5–2.8-cm midline incision is created intraumbilical. After opening the peritoneal cavity, it is necessary to perform a digital exploration of the abdominal wall in order to exclude the presence of adhesions.
The Single-Site™ port can be placed through the umbilical incision using an atraumatic clamp (e.g. Mayo Guyon clamp or Pean forceps) with two different techniques: unfolded or folded clamp technique (Figs. 34.9 and 34.10). In the first technique, it is easier to clamp the port, but it has a larger surface area for entry into the abdomen. The second technique reduces the insertion profile of the port; however, clamping the port can be more challenging. The arrow marking on the port must be aligned with the theoretical anatomical target (gallbladder) (Fig. 34.11). The top port flanges should lay flat against the abdominal wall. If the port seems to be higher than the skin or bulging, the inner rim of the silicone port is likely not completely below the level of the fascia, or the incision may be too small.
Fig. 34.9
Unfolded clamp technique
Fig. 34.10
Folded clamp technique
Fig. 34.11
The arrow marking on the port is aligned with the anatomical target
The endoscope and the accessory cannulae are inserted (Fig. 34.12). The table is placed in slight reverse Trendelenburg (10–15°) and is rotated to the left (5°) for better exposure of the gallbladder. After abdominal exploration, the assistant retracts the fundus of the gallbladder cephalad with a laparoscopic grasper to expose the infundibulum. This procedure is performed to assess port alignment and to ensure an adequate working space for the cannulae and to assure the cannulae length chosen is the appropriate length. The laparoscopic grasper and accessory cannulae are then removed. Curved cannulae are lubricated by dipping in sterile solution and inserted by sight to avoid visceral injury. The robot is then docked. With the cannulae tips in view, the Cadiere forceps are inserted into the robotic arm 1, and the monopolar cautery hook is inserted into robotic arm 2. The assistant then grasps the fundus of the gallbladder to expose the hepatoduodenal ligament. The scope is retracted, repositioned under the grasper and pushed forward. This lifts the grasper (and the fundus of the gallbladder) upwards (Fig. 34.13). The surgeon at the console retracts the gallbladder infundibulum laterally using the Cadiere forceps to open the Calot’s triangle, as in the four-trocar laparoscopy.
Fig. 34.12
Curved cannulae inserted into the port at the end of docking procedure
Fig. 34.13
The scope is retracted, repositioned under the grasper and pushed forward
The instrument positions from top to bottom are as follows: the assistant grasper lifting the gallbladder, the 30° scope is in the centre of the operating field and Cadiere forceps and monopolar hook are at the level below the examination scope. The monopolar hook is used to incise the peritoneum close to the gallbladder neck (Fig. 34.14).
