Benign airway tumors are rare and reported in the literature, and traditional treatment methods mostly use open-heart surgery [1], which is traumatic, has many complications, and is lost due to the inability of some patients to tolerate surgery. In recent years, with the development of bronchoscopy and endoluminal treatment technology, especially the application of rigid bronchoscopy, new treatment means have been provided for the treatment of benign airway tumors. In recent 3 years, we have taken the measures of treating benign airway tumors by rigid bronchoscopy and electronic bronchoscopy under general anesthesia, applying electric coil condenser, carbon dioxide (CO2) freezing, argon plasma coagulation (APC), etc., and achieved ideal results, which are reported as follows: 1. -All of them were patients who lived in Coal General Hospital from April 2008 to December 2011. 5 cases of lipoma, 2 cases of pleomorphic adenoma, 1 case each of papilloma, neurofibroma, malformation tumor and hemangioblastoma were diagnosed by pathological histology. The duration of the disease ranged from 40 days to 19 years, and 11 patients had varying degrees of fever, cough, sputum, wheezing, hemoptysis, and dyspnea. Lesion sites: 7 cases in the main trachea, 3 cases in the left main bronchus, and 1 case in the left upper lobe bronchus. 1.2 Instruments and equipment Electronic bronchoscope: Japan PENTAX EMB3500 type; TV rigid bronchoscope: Germany STORZ type; argon plasma coagulator: Germany CESEL3000 type, output power 30-50W, argon flow rate 0.8-1.6L/min; freezer: Beijing Kulan 320 type CO2 freezing instrument and German ERBE freezing instrument. Electric trap: produced by Nanjing Minimally Invasive Company. 1.3 Treatment method Among 11 patients, 10 cases were operated for the first time by inserting rigid mirror combined with soft mirror under general anesthesia, and 1 case was operated under electronic bronchoscope alone. 1.3.1 Preoperative preparation and anesthesia: preoperative tests, including routine blood, ECG, blood gas analysis, pulmonary function, chest X-ray and CT, were completed. General anesthesia was performed for all scleroscopic operations, and preoperative assessment and anesthesia evaluation were performed by anesthesiologists and clinicians before surgery. Oxygen was administered by mask before anesthesia with preoxygenation for 5 min-10 min. Atropine 0.5 mg or scopolamine 0.3 mg was administered intravenously 10 min before surgery to suppress excessive secretions in the airway. Intraoperative monitoring of oxygen saturation, electrocardiogram, blood pressure and respiratory movements is required. When the operation is performed under a separate electronic bronchoscope, general anesthesia or neuroleptic analgesia plus local anesthesia is used, as appropriate. 1.3.2 Rigid mirror placement and interventional operation method: The patient is placed flat on the surgical bed, and the rigid mirror is inserted under indirect laryngoscopic guidance or direct vision, connected to an anesthesia ventilator, and the patient’s oxygen saturation is maintained at 100%. Before the interventional operation, high-frequency jet ventilation (frequency 40 times/min-80 times/min) is switched, a tee tube is connected, and operations such as electrocoil condenser, APC, and CO2 freezing are performed through the operating hole at the rear end of the rigid scope in combination with electronic bronchoscopy without stopping the ventilator. 1.3.3 Electric coiler : For tumor with tip and long tumor, connect the electric coiler to the high frequency electric knife. Then start high frequency electrocoagulation to cut off the tumor, and then use optical biopsy forceps or freezing to remove the cut tumor. For tumors with wide base or tumor remnants after laparoscopic electrodesection, APC and CO2 cryotherapy are feasible. 1.3.4 APC: The APC probe is extended through the electronic bronchoscopic biopsy hole at the insertion end of the bronchoscope and cautery is started within 0.5 cm from the lesion. Oxygen inhalation need not be stopped during cautery, but intermittent cautery is appropriate (about 5s-10s each time) and should not be too long, and the carbonized and coagulated tissue should be removed with biopsy forceps in time to avoid burning of coagulated necrotic material. 1.3.5 CO2 freezing Soft bendable freezing probe diameter 1.9mm-2.3 mm, probe end length 5 mm. the cold source is liquid CO2. place the metal head of the freezing probe on the surface of the tumor or advance it into the tumor, freeze it for 5s-10s to produce the maximum volume of ice ball around it, remove the probe and its adherent tumor tissues in the frozen state, insert the probe again if necessary, until all the tumors in the cavity are removed. until all the tumors in the cavity are removed. If there is bleeding after the freezing and extraction, then combine with APC to stop the bleeding. 1.3.6 Tracheoscopy is performed at 48-72 hours interval as needed to clean up the necrotic material and cauterize the local residual tumor tissue. For those with a long history and collapsed tracheal stenosis after tumor ablation, a tracheal stent was placed for a short period of time to maintain airway patency. Cardiac and oxygen saturation monitoring were given during the treatment. 1.4 The efficacy was judged according to the degree of airway obstruction, the improvement of clinical symptoms before and after treatment, and the shortness of breath index. The efficacy criteria of airway stenosis recanalization [2] (1) Completely effective, with complete clearance of intraluminal lesions and normalization of function. (2) Partially effective, more than 50% of the stenotic lumen is reopened, the functional examination is approximately normal, and the patient’s symptoms dissipate. (4) Ineffective, with no clinical evidence of subjective and objective improvement. The shortness of breath index score was based on the criteria established by the American Thoracic Society [3]: level 0 was normal; level 1 was shortness of breath during fast walking; level 2 was shortness of breath during walking at usual speed; level 3 was shortness of breath during walking at usual speed and stopping walking due to shortness of breath; level 4 was shortness of breath after light activity. 1.5 Statistical methods Statistical analysis of shortness of breath index and airway narrowing degree measured before and after treatment was performed by SPSS19.0 software with rank sum test. 2. Results 2.1 Treatment: 10 of 11 patients were treated with rigid bronchoscopy combined with electronic bronchoscopy 13 times, followed by the application of electronic bronchoscopy alone 60 times. 1 patient was treated with electronic bronchoscopy alone 2 times. All patients underwent a total of 75 bronchoscopic treatments, with a mean of 6.81 treatments per case; 5 cases of lipoma underwent a total of 15 bronchoscopic treatments, with a mean of 3 treatments per case; 2 cases of pleomorphic adenoma underwent a total of 24 bronchoscopic treatments, with a mean of 12 treatments per case; 1 case of malformation tumor underwent a total of 3 bronchoscopic treatments; 1 case of neurofibroma underwent 16 bronchoscopic treatments; 1 case of papilloma underwent 9 bronchoscopic treatments; and 1 case of hemangioblastoma underwent 6 bronchoscopic treatments. Treatment. 2.2 Treatment effect: The clinical symptoms and signs of 11 patients were significantly improved after treatment, among which 7 cases of the main tracheal masses completely disappeared; 5 cases of obstructive pneumonia completely dissipated and 3 cases of pulmonary atelectasis completely reopened after review of chest CT, and 11 patients were completely cleared of recent tumors after review of tracheoscopy. These 2 cases were misdiagnosed as lung cancer and treated with radiotherapy before treatment, and the lumen collapsed and narrowed after treatment, which required short-term placement of a laminated tracheal stent and removal after airway shaping. The clinical data and treatment status of the patients are shown in Table 1, and the comparison of the degree of airway stenosis and shortness of breath scores before and after treatment is shown in Table 2. Table 1 Summary of clinical data and treatment status of 11 patients No. Gender Age Site of obstruction Degree of obstruction (%) Pathological diagnosis Number of treatments Type of scopes Degree of obstruction after treatment (%) 1 Male 21 Main trachea 80 Papilloma 9 Scleroscope + flexible scopes 0 2 Male 66 Left main 95 Lipoma 2 Scleroscope + flexible scopes 0 3 M 51 Left upper lobe 100 lipoma 2 soft microscopy 0 4 F 54 Main trachea 95 neurofibroma 16 hard + soft microscopy 50 5 F 49 Main trachea 83 pleomorphic adenoma 6 hard + soft microscopy 0 6 F 60 Left main 100 lipoma 3 hard + soft microscopy 0 7 F 63 Main trachea 90 lipoma 6 hard + soft microscopy 0 8 M 36 Main trachea and left main 95 pleomorphic adenoma 18 hard + soft microscopy 40 9 M 73 Left main 80 malignant tumor 3 rigid + flexible 0 10 male 84 Main trachea 80 lipoma 2 rigid + flexible 0 11 male 55 Main trachea 50 angioblastoma 6 rigid + flexible 10 Table 2 Improvement of airway obstruction and shortness of breath score before and after treatment Time Pre-treatment Post-treatment P value Degree of airway narrowing (%) 86.18±14.36 9.09±18.14 0.003 Shortness of breath score 2.64±1.03 0.36±0.00 1.03 0.36±0.67 0.003 2.3 Complications during operation: No complications such as hemorrhage and perforation were found during treatment. 1 patient had a decrease in oxygen saturation during rigid bronchoscopy, which was suspended and changed to direct oxygen supply by anesthesia machine. 1 case was complicated by Staphylococcus aureus and fungal infection after stent placement, which improved after anti-infection and symptomatic treatment. 3. Discussion Benign airway tumors are extremely rare and mostly occur in the main airway. The common benign airway tumors include papilloma, pleomorphic adenoma, neurofibroma, lipoma, hemangioma, smooth muscle tumor, chondroma, and so on. Benign tumors mostly grow slowly and can be asymptomatic in the early stage. When the tumor grows to about 50% of obstruction in the trachea, shortness of breath, dyspnea and wheezing symptoms can appear. When inflammatory ulcers appear on the surface of tumor, blood in sputum may appear. In the past, surgical treatment was the first choice for benign airway tumors, but due to the difficulty and trauma of surgery, postoperative lung function is severely damaged, and some patients cannot tolerate surgery for some reasons. In recent years, there are reports in the literature on bendable bronchoscopic high-frequency electric knife, microwave, laser and other treatments for benign airway tumors [4], which have achieved better results, but when the tumor blockage of the lumen is more prominent and leads to severe stenosis, patients will have obvious respiratory difficulties and may suffocate at any time, and it is difficult to tolerate bronchoscopy under local anesthesia. For this situation, the first treatment mostly adopts rigid bronchoscopy under general anesthesia and electronic bronchoscopic intervention for benign tumors, which can eliminate tumors quickly and relieve symptoms rapidly. After the tumor is eliminated and the airway obstruction is lifted, the subsequent treatment is mostly done under electronic bronchoscopy. The rigid bronchoscope (rigid scope) has been used for more than 100 years to keep the airway open and has a lateral hole at the operating end connected to the ventilator, so it is also called a “ventilating bronchoscope” [5]. The modern value of the TV rigid scope is that it can be used as an interventional channel to allow access of flexible bronchoscopes and other instruments into the airway, which greatly broadens its scope of application. Usually, the rigid scope is used as a channel and guarantees ventilation, and if the tumor is located in the main airway, it can be operated with all kinds of rigid instruments; if the tumor is located in the bronchus, the rigid scope is used as a channel and combined with electronic bronchoscopy for various operations. It not only ensures airway ventilation, but also performs treatment through electronic bronchoscope in areas that cannot be reached by rigid scope. The main means of microscopic treatment include electric traps, APC and CO2 freezing. APC is preferred for tumors with a wide base and superficial tumors, and the coagulated portion is then mucosalized by freezing. APC is a new type of high-frequency electric knife, which delivers high-frequency current to the target tissue through ionized argon gas, avoiding direct contact between electrode and tissue. It avoids direct contact between electrodes and tissues and is a non-contact high-frequency electrocoagulation technique with advantages over high-frequency electricity [6], which can rapidly ablate tumor tissues.CO2 cryotherapy involves placing the metal head of the freezing probe on the tumor surface or advancing it into the tumor so that it can produce a maximum volume of ice balls around it, removing the probe and its adherent tumor tissues in the frozen state, and then inserting the probe again until all the tumors in the cavity are removed. In this group of 11 patients, the tumor was completely cleared and the lumen was unobstructed recently after treatment. The clinical symptoms were significantly improved, and the CT lung atelectasis and obstructive pneumonia disappeared, and the shortness of breath score was significantly improved. This indicates that rigid bronchoscopy combined with bendable bronchoscopy can quickly and effectively remove benign airway tumors, with the advantages of less trauma, faster recovery, preservation of good lung function and fewer complications, which is worthy of clinical promotion. It should be noted that the key to the success of the procedure is the skillful mastery of rigid mirror placement and subscopic intervention and the close cooperation of skilled anesthesiologists. 2 of the 11 patients were treated with external radiation therapy during the hospitalization due to misdiagnosis of lung cancer and required short-term placement of tracheal stents due to tracheal collapse and stenosis during the intervention. In these two cases, 16 and 18 scopic treatments were performed respectively, which increased the pain and economic burden of the patients and prolonged the course of the disease. Therefore, it is necessary to follow the principle that the pathological diagnosis of tumors in the airway should be clarified before using reasonable treatment.