Since the 1990s, thoracoscopic technology has been widely used and developed in thoracic surgery. Thoracoscopic surgery inevitably has its own limitations, such as limited visual information with 2-dimensions、restricted maneuverability of instruments, an unsteady camera platform, etc. The Da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA) has revolutionized minimally invasive surgery by offering a more minimally invasive and precise approach to surgery6.
Da Vinci robot-assisted surgery system is composed of three parts: surgeon control platform, patient cart and 3-dimensional view high-definition video cart. The robot-assisted thoracic surgery approaches can be performed with either 3 or 4 robotic arms. Though a few surgeons used a completely port-based approach (4 robotic arms and no assistant port) with the closed chest insufflated with CO2, 3 robotic arms and an assistant port were more popular used during the robot-assisted thoracic surgery. The selection of robot-assisted surgical incision should follow certain principles, which could ensure that the instruments are flexible in the thoracic cavity during the surgery and without interfering with each other. The general principle of surgical incision selection is that the distance between camera port and the incisions for the first robotic arm and second robotic arm should be more than 8cm. The triangle target principle for the placement of trocars during video-assisted thoracic surgery was firstly named by Sasaki etal7 and these principles should be followed during robot-assisted thoracic surgery. According to our experience, the incision for the camera port, which serves as the vertex of the isosceles triangle, and its connection with the incisions for the first robotic arm and second robotic arm form an isosceles triangle. The selection for the assistant port should not be placed in the isosceles triangle to the greatest extent, as shown in Figure 2. There are many types of thoracic surgery, including lung, esophagus and mediastinum tumor surgery. While the thoracic cavity is huge and requires extensive coverage, different operations have different emphases and different exposure of the surgical area. For example, esophageal surgery is mainly located in the post mediastinum, and lung surgery mainly requires wide exposure from the lung hilus to tracheal carina、superior mediastinum, while mediastinal tumor surgery requires different exposure parts according to different lesion location. Therefore, in selecting the robot surgical incision, different surgeons usually have different choices6, 8-22, as shown in Table 3. Even for lung surgery, at present there are still a variety of robot-assisted surgical incision selections 6, 9, 14-17, 19, 20, 22. Daniel S et al 23summarized the robotic port placement which was used by high-volume thoracic surgeons in the United States who performed robot-assisted lobectomy and they found that the precise locations of the robotic ports were heterogeneous for each lobectomy. The most common locations for camera and instrument trocars were the seventh and eighth interspaces for all types of lobectomies. It was clearly flexible in where to place trocars for robot-assisted lobectomy, just based on experience or the unique anatomic issues of a specific patient. These incisions are only suitable for lung surgery or esophageal surgery, mediastinal tumor surgery,it has not been a universal incision for robot-assisted thoracic surgery.
Table 3
The brief summary of the incisions for robot-assisted thoracic surgery
| Camera port | The first robotic arm | The second robotic arm | The assistant port | The third robotic arm |
Lung Surgery | | | | | |
Veronesi G etal6 | 7th ICS in the midaxillary line | 4th ICS in the anterior axillary line | 8th ICS in the posterior axillary line | / | 7th ICS behind the scapular line |
Pardolesi A etal16 | 7th/8th ICS in the midaxillary line | 8th ICS in the posterior axillary line | posteriorly in the auscultatory triangle | 4th/5th ICS in the anterior axillary line | |
Zhao X etal22 | 8th ICS in the midaxillary line | 7th ICS behind the posterior axillary line | 5th ICS in the anterior axillary line | 9th/10th ICS in the posterior axillary line | / |
Li JT etal14 | 8th ICS in the posterior axillary line | 7th ICS in the midaxillary line | 9th ICS infrascapular line | 4th ICS anterior axillary line | |
Esophageal Surgery | | | | | |
Kim DJ etal13 | 8th ICS infrascapular line | 10th ICS infrascapular line | 6th ICS medial to the scapula at the posterior axillary | 7th ICS along the mid-axillary line | |
Kingma BF etal10 | 6thICS approximately 1/3 of the distance between the posterior axillary line and the tip of the scapula | 10th ICS frascapular line | 8th ICS approximately 1/3 of the distance between the posterior axillary line and the tip of the scapula | 5th ICS dorsal to the posterior axillary line | 4th ICS approximately 1/3 of the distance between the posterior axillary line and the tip of the scapula |
Anterior -mediastinum Surgery | | | | | |
Augustin F etal8 Kamel MK etal12 | 5th ICS in the anterior axillary line 6th ICS in the posterior axillary line | 3th ICS in the anterior axillary line 3th ICS in the anterior axillary line | 5th ICS in the midclavicular line 5th ICS in the anterior axillary line | 5th ICS in the midaxillary line | |
As there are many types of thoracic surgery, the variety of incision selection brings some difficulties to the chief surgeon, especially the beginner to carry out robot-assisted surgery. Robot-assisted surgeons are skilled in thoracoscopic surgery, and the learning curve of robot-assisted surgery is much shorter than that of thoracoscopic surgery24-26. Based on the practice, exploration, and summary of more than 300 cases of robot-assisted surgery, the concept of universal thoracic incision in robot-assisted surgery was proposed: The incision for the camera port was placed at the midaxillary line in the sixth ICS . The incisions for the first robotic arm were placed at the anterior axillary line in the third ICS, the incision for the second robotic arm was placed at the subscapular line in the ninth ICS, and the assistant port was placed at the anterior axillary line in the fourth ICS. This incision is applicable to all lung, esophageal surgery and posterior mediastinal tumor surgery. For the anterosuperior mediastinal tumors, the incision for the second robotic arm was adjusted at the anterior axillary line in the sixth ICS. If necessary, the assistant port could be adjusted at the posterior line axillary in the eighth ICS. The distance between the incisions for the first robotic arm、 the second robotic arm from the camera port should be kept a palm wide (about 8 cm). The incision for the camera port should be done first in practice, and the remaining incisions were placed under direct visualization so as to guarantee the incision within the thoracic cavity. Blind operations are strictly forbidden to avoid injury to the diaphragm or enter the abdominal cavity.
Among the 342 cases of clinical surgery, there were 107 cases of esophageal cancer surgery (Mckeown approach), 5 cases of esophageal leiomyoma, 178 cases of lung surgery, 52 cases of mediastinal tumor operation.Two cases of early surgery cases were transferred to endoscope-assisted surgery with a small incision for serious chest adhesion, and the remaining cases did not transfer to endoscope or thoracotomy and all the surgeries were all successfully completed, with no death cases during the perioperative period and one month after surgery. The initial design of this robot-assisted thoracic incision is given priority to esophageal surgery, and nearly all of the 40 robot-assisted surgery cases during the early period were esophageal tumor patients. Based on the robot-assisted surgery experience, it is found in the subsequent lung surgical explorations that the universal incision for lung surgery also has very good exposure and operation effects. Thus, lobectomy and segmentectomy were carried out afterward. The assistant port was placed at the anterior axillary line in the fourth ICS, which fits the operation habits of endoscopic surgery, especially the exposure in single-hole endoscopic surgery and the placement of linear cut stapler. It is convenient for the assistant with single-aperture surgery experience to operate on the table and shorten the time for skilled coordination between the assistant and the chief surgeon. The location of the assistant port in the anterior chest wall is also conducive to rapid thoracotomy in case of emergency of massive bleeding during the surgery(although such situations have not been encountered by us). Recently, 2 cases of esophageal cancer complicated with nodules in the upper lobe of the right lung have successfully passed through this surgical incision. After the separation of the esophagus and lymph node dissection, the resection of the right upper lobe was completed, which further reflected the superiority of the universal surgical incision. The EndoWrist® in the da Vinci system is superior to the human wrist, as it is flexible in all directions.There are a few reports about the cases of robotic-assisted thoracic surgery (RATS) sleeve or double-sleeve lobectomy for central-type lung cancer27-30[29-32]. Due to the small number of surgical cases, only 3 cases of bronchial sleeve resection of the pulmonary lobe(1case for the right upper pulmonary lobe and 2 cases for the left upper pulmonary lobe) have been completed. The 3-0 prolene sutures (ETHICON 24 mm 1/2c, USA) in a continuous way was used to perform the bronchial sleeve resection. It was more successful for intraoperative sutures than thoracoscopic sutures, which showed a great advantage over the former.
For the anterior mediastinal tumor, the lesion is located in the substernal part with narrow space. When the lesion is too large, its exposure under the thoracoscope is poorer. The advantages of robot-assisted surgery are obvious for fine operation within such a narrow space. For the anterior mediastinal tumor, the incision for the second robotic arm is moved to the anterior chest wall and the anterior superior mediastinal tumors with lesions below 3cm can be completed independently without assistant port, while solid tumors with lesions above 3cm often require additional assistant port to enhance the exposure of the operative field. The assistant port can be palced at the posterior axillary line in the eighth ICS. The largest anterior superior mediastinal tumor (solid thymoma) t has been completely excised by us through this incision which was nearly 8 cm in diameter, avoiding thoracotomy or the sternum split and minimizing trauma to the patient.
Good robot surgical incision design is the premise of successful operation and display of robot platform advantages. Relatively simple and fixed general surgical incision, good intraoperative exposure, and quick and skilled cooperation of the assistant can reduce the difficulty of robot-assisted surgery for the surgeon and shorten the learning curve of robot-assisted surgery. Our preliminary experience suggests that universal robot incisions are feasible for esophageal, lung, and most mediastinal tumors. The proposal of a universal robot incision provides a simple and easy incision design for more and more thoracic surgeons to ensure the smooth and successful development of robot-assisted surgery.
This paper also has some limitations. Due to the small number of surgical cases, there is no relevant experience in Ivor Lewis approach for esophageal cancer and pulmonary artery plasty, and only 3 cases of bronchial sleeve resection have been completed. In addition, this paper only included the date of two surgical centers. More surgical centers need to try and verify the safety and convenience of this universal incision. However, this universal incision for robot-assisted thoracic surgery has great value as it may guide standardized port placement, which would be important for the learner and the instructor.