Most posterior mediastinal tumors are of neurogenic origin and arise from the thoracic of neurological origin from the peripheral, sympathetic and parasympathetic nerves within the The tumours are of neurogenic origin [9,10]. Histologically, mediastinal tumours of neurogenic origin can be divided into nerve sheath tumours, sympathetic tumours (ganglion cell tumours account for approximately 40%-60% of tumours) and neurofibromas. Currently, surgery is the main treatment main treatment modality.
In traditional open-heart surgery for posterior superior mediastinal neurogenic tumours, it is difficult to obtain a satisfactory view of the tumour due to its the high location of the tumour makes it difficult to obtain a more satisfactory surgical view. Although thoracoscopic surgery may to some extent meet the requirements for surgical field of view requirements, its 2D-only imaging system is sometimes difficult to obtain high quality surgical images. The da Vinci robot's naked-eye 3D imaging technology provides high-quality magnified images that can magnify the surgical field 10-15 times in three dimensions, allowing the operator to obtain a high-quality surgical image that facilitates the identification of the tumor's feeding vessels and its relationship to vital nerves [11]. The two ganglion cell tumours in this group were located at the entrance to the thorax at the top of the pleura The upper part of the tumor was located deep to the neck. The thoracoscopic surgery is difficult to perform because of the high level of stability and precision required for open-heart surgery, which is only possible with a "semi-clam incision" [12].
Due to the high tumor position and small operating space of the tumor of the rear neuronal nerve source, the surgical field of vision is poor during routine opening surgery, the tumor leakage is difficult, and the movement of surgical instruments during thoracoscopy is often limited [13]. The difficulty of dissection is caused by losing accuracy, and the accuracy of the robot surgery system is excellent. Some neurogenic tumours tend to adhere to the surrounding tissue, making it more difficult to separate and ligate the feeding vessels of the tumour. For tumours originating from important motor nerves or in close proximity to important nerves, there is a high risk of nerve collateral damage due to the small operating space and the difficulty of handling surgical instruments. The robotic arm of the Da Vinci Robot Surgery System has 7 free activity of wrist type, including advanced and retreating, wrist rotation, bending up, down, left and right directions, and the end -of -right grabbing movement [14]. The activity space in the limited surgery field and fixed angle can be extended to the areas where traditional equipment cannot reach. These features of the da Vinci robotic surgical system allow it to operate not only in tight spaces, but also to expose the surgical area more fully and provide a better view of difficult anatomical areas, thus allowing surgeons to precisely isolate and treat blood vessels and vital nerves, improving surgical safety [15]. In this group, 28 tumours were located in the posterior superior mediastinum and were closely related to the sympathetic chain. 9 ganglioneuroblastomas were located at the entrance to the thorax and originated from the sympathetic chain. After fine intraoperative dissection, 2 cases developed Honor's syndrome postoperatively, which was observed with oral vitamins, etc. the symptoms partially recovered and 1 case developed an absence of sweating in the affected upper limb, otherwise no significant neurological complications were observed. As proficiency in the operation increases, the number of accidental and unnecessary injuries unnecessary injuries are gradually reduced.
The da Vinci robotic system requires only one 1.2 cm incision for access and two 0.8 cm incisions for manipulation of the posterior mediastinal neurogenic tumour. The intraoperative use of an 8 mm Hg pneumothorax does not increase airway resistance, but significantly increases intraoperative exposure. Usually we do not use an auxiliary port, and when gauze is fed, or when haemostatic powder needs to be sprayed on the wound, simply withdraw the instrument temporarily and feed it through the instrument hole; when the tumour needs to be removed after excision, remove one arm trocar and use the endoscopic retriever to remove the specimen. We usually use an anterior chest wall incision to remove the specimen because of its wide rib space and thin muscle tissue. In the early stages, it takes longer to remove the specimen from the tiny single hole, and then it is easier to remove the specimen by extending the incision to the size of the tumour diameter.
For robotic surgery, the position of the body and incision determines the ease and even the success of the procedure. Usually we choose the 6th intercostal space in the posterior axillary line as the observation hole position. When the tumour is in a high position, we choose a lateral folding position to prevent the lens arm from compressing the hip, and the instrument arm holes are chosen at the 4th intercostal space in the anterior axillary line and the 7th intercostal space in the posterior axillary line. Unlike lumpectomy or open surgery, it is not the case that the closer the incision is to the swelling, the closer the incision is to the swelling, the greater the movement of the large arm when the tip of the instrument is moved laterally the same distance, causing more opportunities for collision and thus limiting the movement of the instrument, so choosing a more distant incision is more beneficial to the operation.
In the operation, we operate the bipolar electrocoagulation grasper with the left hand and the electrocoagulation hook with the right hand to complete all the operations. The electrocoagulation hook is separated by layered electrocoagulation and the bipolar grasper deals with the trophoblastic vessels and assists in the exposure, but because the tumour is usually brittle and does not have a hard and tough outer membrane, and the grasper does not have force feedback, it cannot complete the "clamping" action during the freehand operation.