The operating room technical staff sets up the robotic surgical system (surgical cart, surgeon's console, vision system) in the room (Fig. 167-2). In the beginning of the case, the nursing staff power up the system, run the appropriate diagnostics, and drape the robotic arms and camera. This requires two individuals and typically takes 5 to 10 minutes for staff who are trained and familiar with the process and occurs prior to or while the patient is undergoing induction of anesthesia and positioning.
Robotic surgical system. A. Surgical Cart. B. Surgeon console.
Anesthesia Considerations and Patient Positioning
Standard methods of induction of general anesthesia and endotracheal intubation are used. Single-lung ventilation via either double-lumen endotracheal tube placement or bronchial blocker, while not mandatory, greatly facilitates the procedure and can be initiated early once correct tube position has been verified bronchoscopically or clinically. Patients with MG are exquisitely sensitive to nondepolarizing muscle relaxants, and their use should be avoided as much as possible. Anesthesia can be maintained with volatile, inhalational agents. If muscle relaxation is necessary, a reduced dose of intermediate-acting nondepolarizing agents can be employed at the beginning of the procedure.
The patient is placed in a supine position with the ipsilateral side elevated 30 degrees with a gel roll or padding placed longitudinally below the tip of the scapula. The contralateral arm is padded and tucked. The ipsilateral arm should be slightly abducted, padded and placed on an armboard that is fully adducted in line with the operating room table so that the arm and shoulder are below the anterior chest. The operating table is moved away from the anesthesia machine and angled with the foot of the table away from the surgical cart. This establishes enough space to dock the robot which will be positioned at the contralateral side. Thus, with a left-sided robotic approach, the left side of the patient is elevated with the robotic cart docked from the right side of the table. Care must be taken to insure that sufficient length of the circuit tubing is available during this positioning, and the anesthesia team must be comfortable that there is adequate access to the patient's airway once docking of the robotic system has taken place. The entire neck and chest below the xiphoid process should be prepped and draped in the event that a transsternal or contralateral incision is needed.
Initial Exploration and Docking of the Robot
Robotic thymectomy is a three-incision, three-arm procedure. Initial thoracic exploration is conducted with the robotic thoracoscope through a 12-mm port in the fifth or sixth intercostal space (ICS) in the anterior axillary line. Use of CO2 insufflation to 8 to 10 mm Hg is generally well tolerated and enhances the visualization and working space by increasing the anteroposterior diameter of the chest. The anesthesia team should be alerted to the initiation of insufflations so that they may monitor the patient's airway and blood pressure. When operating on the left side, care must be taken in making this initial incision as it will be quite close to the pericardium. The camera port should be placed without the use of a sharp trocar and CO2 insufflation should be initiated prior to placing the subsequent ports.
The remaining ports are 8 mm reusable metal robotic ports placed under robotic thoracoscopic visualization. Because the working space is limited, it is critical to space the ports at least one handbreadth apart to avoid arm collisions that will limit full range of motion of the instruments in the chest. The second port is placed in the sixth or seventh ICS in the inframammary crease in the midclavicular line. The last port is placed in the third or fourth ICS anterior to the anterior axillary line. Once all three ports have been placed, the surgical cart is brought into position from the contralateral side with the center column and camera arm in a line between the camera port and the contralateral shoulder. It is important to position the arms within the working range and avoid having them too close to the ports and the patient as this will limit the working range of the instruments.
Once the surgical cart is in position, the camera arm is attached first to the 12-mm port. The camera arm and port are used to elevate the anterior chest wall for increased visualization. The robotic thoracoscope is introduced and secured to the camera arm. A 0-degree scope is preferred for the initial dissection and avoids excessive torque in the interspace. The remaining ports are attached to the robotic arms, and the surgical instruments are introduced under direct thoracoscopic vision. A Cadiere forceps is most commonly controlled by one hand for grasping tissue, and a cutting instrument (monopolar spatula, Maryland bipolar, monopolar hook) is used in the other hand. After the instruments have been introduced, the operating surgeon moves to the surgeon's console. The first assistant remains at the table and performs instrument exchanges as needed. A separate, nonrobotic assistant port is typically not required.
Dissection is initiated by incising the mediastinal pleural medial to the phrenic nerve. It is easiest to begin in the midpoint of the pericardium where fat content is lowest. The perithymic and pericardial fat is mobilized along the entire length of the phrenic nerve from cephalad to caudad off of the pericardium as far toward the contralateral chest as is convenient. CO2 insufflation greatly facilitates dissection once the mediastinal pleural is divided. Dissection at the ipsilateral anterior diaphragmatic recess can be limited by instrument conflict. It often helps in this situation to retract with the superior instrument arm and divide the tissue with the inferior arm.
Next, the mediastinal pleural just posterior to the posterior table of the sternum is incised from the thoracic inlet to the diaphragm and from the ipsilateral to the contralateral pleural space. The contralateral pleura is divided completely, allowing dissection up to the contralateral phrenic and for greater manipulation of the specimen as the mobilization proceeds. The dissection continues cephalad and toward the contralateral pleural space by dividing en bloc all attachments of the specimen to the pericardium. Visualization of tissue at the limits of the contralateral pleural space is improved through the use of the 30-degree robotic thoracoscope.
Once the majority of the specimen has been mobilized off the pericardium toward the neck, the ipsilateral portion of the innominate vein is identified. The superior horns are bluntly separated from the innominate vein. The thymic veins are isolated and divided either by serial clips or through the use of the robotic harmonic scalpel. Similarly, the superior horns are freed from the surrounding attachments, pulled inferior out of the neck and either clipped and divided or resected by harmonic scalpel. It is useful to place a clip of one of the horns for proper orientation of the specimen once ex vivo. Visualization can be improved by allowing the already mobilized portion to fall into the contralateral pleural space. After all of the tissue from the thoracic inlet has been freed, the remaining attachments to the anterior surface of the pericardium medial to the contralateral phrenic should be divided. At this point, if not done so previously, a change to the 30-degree thoracoscope in a downward orientation will facilitate identification and avoidance of the phrenic nerve.
Once the entire gland and surrounding tissue have been completely mobilized, the inferior port may be removed. Removing the specimen from this incision is preferable because the rib space is widest in the anterior position. When the thymoma or other thymic mass is larger than the initial incision, the incision should be enlarged with an Anchor™ tissue retrieval bag (Anchor Products Company, Addison, Illinois) or other suitable bag is placed through it to retrieve the specimen. A durable nylon bag is preferred to plastic to minimize the chance of rupture and spillage. A conventional thoracoscopic grasper can be introduced in the superior port manually and used to grasp the specimen. The sac should be positioned such that the full extent of the bag may be opened toward the contralateral chest. Once the specimen is placed into the bag, it is removed (Fig. 167-3).
Robotic thymectomy specimen.
Termination of the Procedure
After the specimen has been removed, the operative bed should be inspected for any signs of active or potential bleeding. Any blood or clots should be irrigated and removed. The ports are then removed, and a single chest tube is placed through the camera incision and positioned with the tip at the apex of the ipsilateral chest or in the anterior mediastinum. The lung should be reinflated under direct thoracoscopic vision with the robotic scope placed in the inferior incision. The remaining wounds are closed in a standard fashion.