Mediastinoscopy is one of the best tools for diagnostic and therapeutic thoracic surgery, to give you a brief introduction. Mediastinoscopy and its applications: Mediastinoscopy is a major method to clarify mediastinal lesions and their nature. A mediastinoscope is placed through a small incision in the neck to visualize, palpate and biopsy directly around the trachea, under the tracheal ridge and the bronchial region. The information obtained can be used for diagnosis. Secondly, mediastinoscopy can be used for uniform and accurate staging of lung cancer, so that treatment plan and prognosis can be reasonably formulated. Indications for mediastinoscopy: 1. To clarify the nature of mediastinal masses. 2.To observe the metastasis of mediastinal lymph nodes of lung cancer and decide whether it can be surgically removed and assist in staging. 3.To clarify the nature of the enlarged mediastinal lymph nodes, whether they are metastases or other disorders, such as tuberculosis, nodular disease, histoplasmosis and lymphoma, etc. 4.For treatment, such as removal of thymic tissue in the mediastinum, thymoma, bronchial cysts and implantation of pacemakers. Contraindications to mediastinoscopy: aortic aneurysm, superior vena cava syndrome, severe anemia or bleeding tendency and cardiopulmonary insufficiency, cachexia, etc. In addition, caution should be exercised when performing the second mediastinoscopy. Mediastinoscopy (1) Standard mediastinoscopy (SCM) is suitable for those whose masses are located around the trachea, in the right pulmonary hilum and under the bulge. The anterior tracheal space is entered through a neck collar incision and advanced downward along this space to reveal enlarged lymph nodes or mediastinal masses in the above-mentioned areas, and biopsies are taken by bite. However, SCM cannot reveal the anterior mediastinum, the left hilar and aortic windows, nor can it perform biopsies of peri-esophageal lymph nodes and lymph nodes of the inferior pulmonary ligament behind the bulge. Since the mediastinal lymph nodes are mainly located in the peri-tracheal area, bilateral hilum, inferior bullae and aortic window, and the enlarged peri-tracheal lymph nodes are the most common in clinical practice, they are the most satisfying and ideal site for SCM, and the best area for SCM. (2) Expanded mediastinoscopy If the mass is located in the anterior mediastinum or the main pulmonary window and the left hilum, SCM cannot reach this area, it can be performed through a cervical incision into the posterior sternal space, or through the 2nd or 3rd intercostal incisions on the left and right sides of the sternum, into the anterior mediastinum or the main pulmonary artery and the left and right hilum (taking care to avoid damaging the pleura as much as possible), which can generally reveal the mass in these areas satisfactorily. Care needs to be taken during the operation not to damage the phrenic or vagus nerves passing through the aortic arch, as well as the large vessels such as the innominate artery, carotid artery, aorta and pulmonary artery. Since mediastinal puncture biopsy is clinically performed for anterior mediastinal masses, while simple aortic windows and masses in the left hilar region are not common, and if they are accompanied by left pulmonary lesions, they can be operated directly by open thorax if they are clinically judged to be surgically resectable, fewer patients have such examinations performed. At present, mediastinoscopy is mainly used to determine the nature of mediastinal masses, lymph node biopsy or lung cancer staging. (1) The application of mediastinoscopy in the diagnosis of thoracic diseases The mediastinum has complex structures and diverse tissue origins, including multi-system tissue structures of three germ layers. More than 10 types of benign and malignant mediastinal tumors are known, which is the most complicated area in the human body structure where tumor types occur. Except for thymoma, teratoma and neurogenic tumor, which are easy to diagnose clinically because they have certain preferential sites and imaging features, other types of tumors are difficult to diagnose only by imaging. The mediastinal area is not connected to the external cavity, so the common endoscopic techniques cannot work, and mediastinal puncture biopsy is also difficult, so it has become a difficult point in the diagnosis of chest diseases. Because of the diversity of mediastinal diseases, their treatment and prognosis are very different. According to RamiPorta, imaging of the mediastinal region does not always correctly reflect the pathological characteristics of the tissue and therefore often does not provide an accurate basis for treatment decisions. In contrast, standard mediastinoscopy can obtain accurate pathology of lymph nodes in the mediastinal region (1,2R,2L,3,4L,7,10R) and nearby regional tumors; expanded mediastinoscopy, as a supplement to standard mediastinoscopy, can detect lymph nodes in regions 5 and 6, so it can provide an accurate basis for the diagnosis of mediastinal disease. According to Liu Xiangyang et al, the best indication for mediastinoscopy is the enlarged mediastinal lymph nodes caused by various reasons. 2, the best examination area is the middle mediastinum, i.e., around the trachea (including part of the subsurface of the bulge and at the right hilum), especially the right paratracheal area. 3.The most valuable result of mediastinoscopy is that it enables some cases with imaging diagnosis of suspected malignant tumor to be diagnosed as benign lesions, which avoids misdiagnosis and mistreatment caused by imaging diagnosis alone, and also enables other tumor patients to obtain accurate pathological diagnosis and thus receive reasonable and standardized treatment. (2) The value of mediastinoscopy in lung cancer staging and treatment The agreement between clinical cTNM staging and postoperative pathological pTNM staging of lung cancer is only 45.3%, which is due to the unknown presence of mediastinal lymph nodes metastasis. Reviewing the literature, it is reported that mediastinoscopy can examine patients without mediastinal lymph node metastasis, provide accurate basis for staging and treatment of lung cancer, avoid unnecessary open-chest exploration for some incurable cases, and help to correctly stage cases ready for adjuvant treatment. (3) Complications of mediastinoscopy Mediastinoscopy is less invasive, less expensive and more accurate than open-chest surgical exploration or thoracoscopy. However, mediastinoscopy is, after all, an invasive examination and carries certain risks. This shows that mediastinoscopy, as an effective method for characterizing mediastinal lesions, is operated by experienced surgeons and has a low complication rate. Some even believe that mediastinoscopy can be safely used in most outpatients. (4) Limitations of mediastinoscopy Like most clinical examination methods, mediastinoscopy also has its limitations, such as the anterior mediastinum, posterior trachea and other areas distant from the trachea, as well as areas that cannot be observed due to vascular obstruction, which are not accessible by mediastinoscopy and should be classified as blind areas for mediastinoscopy. For the masses or lymph nodes here, anterior mediastinotomy should be performed if necessary, or combined mediastinoscopy and thoracoscopy should be performed at the same time to make up for the lack of mediastinoscopy. Mediastinoscopy was introduced into our clinic in 1970s, and it is an important means of differential diagnosis of mediastinal diseases. With the emergence of new technologies such as CT, MRI, ultrasound and mediastinal puncture biopsy, the clinical application rate of mediastinoscopy has gradually decreased. However, practice shows that various new examination methods have both advantages and characteristics and limitations. Our experience is that the organic combination of various examination methods can significantly improve the accuracy of diagnosing diseases. Mediastinoscopy combined with various new technologies will have a broader scope of application. At present, video technology combined with mediastinoscopy is used in clinical practice, which not only expands the field of view of mediastinoscopy, but also greatly improves the accuracy and simplicity of operation. Studies have shown that mediastinoscopy is still a safe and effective method of mediastinal pathological examination, which can obtain a clear pathological diagnosis of mediastinal diseases before the implementation of treatment and can avoid the harm brought to patients by misdiagnosis and mistreatment.