I. Respiratory endoscopy
1, bronchoscopy: including flexible and rigid bronchoscopes, currently developed from ordinary bronchoscope to ultra-fine bronchoscope, therapeutic bronchoscope, fluorescent bronchoscope, ultrasound endoscope, narrow wave light bronchoscope, etc.. The rigid bronchoscope has also developed into a TV-assisted image system with various operating holes at the end of the cannula for easy connection to a ventilator and various operations, which is called a “ventilating bronchoscope”, and has also improved the operating accessories.
2. Internal thoracoscopy is mainly used for the diagnosis and simple treatment of pleural cavity diseases and lung diseases.
Application scope of respiratory endoscopy
1.Application in diagnosis: common lung and mediastinal diseases include: lung tumor, lung infection, unexplained hemoptysis, mediastinal lymph node enlargement and pleural diseases, etc.
2.Therapeutic application: mainly used for various causes of tracheal stenosis of the right and left main bronchus and right middle bronchus.
Commonly used methods include the following.
(1) Thermal ablation techniques: including high-frequency electric knife, argon plasma coagulation, laser, microwave, etc.
① High-frequency electroknife.
Endotracheal high-frequency electrokinetic treatment is a method of thermal coagulation and cutting of intraluminal tumor tissues by reaching into needle or loop electrodes through the tracheoscope, which is a contact treatment. A tiny probe acts as an activated electrode, and heat is concentrated through the tiny probe in a punctiform area on the surface of the contact tissue, resulting in coagulation or vaporization of the tissue. The degree of tissue destruction depends on the power used, the length of contact time, the size of the contact area and the density and humidity of the tissue. At present, there are many models of high-frequency electric knife at home and abroad, but according to the different uses can have three functions: electrocutting, electrocoagulation and mixing.
Indications: ① granuloma: including post-surgical granuloma, inflammatory and foreign body granuloma; ② malignant tumor in the trachea or bronchus: absolute indication when the opportunity of surgery is lost, postoperative recurrence, irradiation and chemotherapy have lost their effect; ③ benign tumor in the trachea or bronchus, but the effect is not good for those with long stripes and wide base; ④ bronchial stenosis caused by trauma scar; ⑤ primary tracheal a bronchial amyloidosis, etc. . Complications include tracheal perforation, mediastinal emphysema, hemorrhage, etc.
②Argon plasma coagulation (APC): APC is a new type of high-frequency electric knife, commonly known as argon knife. It is a non-contact high-frequency electrocoagulation technique by delivering high-frequency current to the target tissue through ionized argon gas, which avoids direct contact between electrodes and tissue. For tumors causing obstruction in the airway, APC can be used for rapid ablation and relief of obstructive symptoms. No matter the tumor occurs in the main trachea or the left or right bronchus, APC can eliminate about 60% of the tumor each time. For tumors with relatively limited lesions, basic clearance can be achieved at one time. However, for tumors with wider base, multiple times of gradual removal is needed. For larger tumors in the lumen, it is better to combine APC with cryosurgery under hard microscope, which can remove the tumor at one time. The cautery range should exceed the tumor border by about 1 cm. On the third day, bronchoscopy should be performed again to clear the necrotic tissue and cauterize the residual tumor again if necessary. For intraluminal tumors causing pulmonary atelectasis, the size of the tumor should be estimated before surgery, and the tumor should be removed systematically until the lumen is opened.
③ Microwave is a kind of high frequency electromagnetic wave, which is an internal heating method using the internal biological tissue itself as the heat source and producing non-conductive heat by using its abundant aqueous components. Microwaves achieve therapeutic purposes through thermogenic and non-thermogenic effects.
Microwave is mainly used for central lung cancer (endotracheal type) with bronchial stenosis and obstruction that is not suitable for surgical treatment in airway diseases. Postoperative recurrence of lung cancer with large airway obstruction. Those with narrowing caused by benign tumor or granuloma in the airway. Bleeding within the reach of bronchoscopy.
Microwave thermotherapy can effectively kill the tumor tissue in the bronchial lumen, reduce the infiltration of cancer in the tube wall, reduce the tumor load, release the airway obstruction, reopen the non-distended lung, promote the absorption of inflammation, reduce the clinical symptoms and improve the survival quality of patients; among them, the efficacy is significantly better than that of patients with luminal mass type and central type lung cancer with infiltration of mass type. It can make some patients with benign airway tumors avoid surgery, and the treatment effect can almost reach or even be better than that of surgery.
④Laser cautery treatment
There are two main types of lasers in clinical application, namely, CO2 laser and Nd:YAG laser. CO2 laser can only be operated under rigid microscope, which is only suitable for hemostasis of capillary bleeding, but not effective for tumor hemorrhage. In order to compensate for the limitations of CO2 laser, Tony et al. started to apply Nd:YAG laser to treat endobronchial lesions through bronchoscopy under intuition in 1982. Currently, the Nd:YAG laser is mainly used to treat endotracheal-bronchial obstructive diseases by cauterizing and destroying tissues, charring and vaporizing them, rapidly eliminating benign and malignant tumors in the airways, significantly improving patients’ quality of life and prolonging their life expectancy. The laser can also be used to destroy damaged metal stents to facilitate correction or removal of the stent. For foreign bodies that are difficult to remove, the laser can also be used to break them up and facilitate their removal.
However, hypoxemia and perforation of the tracheal wall are likely to occur during laser treatment and should be carefully operated and closely monitored.
(2) Cryosurgery
Cryosurgery is a method of destroying abnormal living tissues by using ultra-low temperature. According to the Joule-Thomson principle, high-pressure CO2 gas is released through small holes and throttled to expand and cool to produce low temperature, the lowest temperature can reach -80℃, forming a certain size of ice ball in the front section of the cryoprobe, which can effectively kill the tumor.
Cryopreservation is performed with a cryoprobe in the working channel of the tracheoscope. The front end of the cryoprobe has a diameter of about 1.7 to 2.4 mm, a length of about 100 cm, and an end length of about 7 mm, characteristics that allow it to perform cryotherapy within the working channel of the bronchoscope. The end of the cryoprobe can act directly on the tumor area to form an ice ball of about 15 mm, which can be divided into two types: freeze-cutting and freeze-thawing, depending on the purpose. The cryoprobe is removed together with the frozen tissues, which is called cryotomy and is commonly used for the removal of intracavitary tumor (or granulation) tissues, necrotic materials or foreign bodies; while the tissues are continuously frozen in situ for 1 to 3 minutes to produce -60℃ to -70℃ low temperature and secondary tissue necrosis, which is called freeze-thaw and is commonly used for the freezing of benign lesions or residual tumors.
(3) Brachytherapy
Radioactive 125I particles (which can release γ-rays, also known as in vivo γ-knife) are usually bundled with radioactive particles on an internal stent to both support the narrow trachea and provide brachytherapy to the tumor. 125I particles can also be implanted into the tumor tissue around the airway or metastatic lymph nodes that cannot be removed surgically under direct bronchoscopic view, and continuous radiotherapy can be administered to control the tumor growth.
(4) Local drug therapy
Intraluminal local drug injection: For those who are clearly malignant endotracheal tumor, it can be combined with cryotherapy and thermotherapy, and intra-tumor injection of chemotherapy drugs to play a synergistic treatment role.
The drugs commonly used for intratracheal injection are chemotherapy drugs (cisplatin, mitomycin, epi-amycin), anhydrous alcohol, interleukin-2 (IL-2), and genetic drugs (currently, the drugs used in clinical practice are recombinant human p53 adenovirus injection (Imazan), etc.). In recent years, recombinant human p53 adenovirus has been administered by intra-tumoral injection for medium to late stage head and neck squamous carcinoma and lung cancer, and has achieved very good efficacy.
(5) Balloon catheter dilation and angioplasty
The balloon catheter is introduced into the bronchoscope and balloon dilation is performed on the narrow proximal airway, which can produce multiple small longitudinal lacerations around the entire circumference of the narrowed airway, and the lacerations are filled with fibrous tissue, thus achieving the purpose of dilation of the narrowed area.
Indications.
Indicated for fibrous or non-fibrous stenosis of the central airway due to various causes
Balloon dilation is a simple, safe and fast method, which does not require general anesthesia, special equipment and complex techniques, and can avoid bronchial perforation caused by laser treatment, etc. It is more economical, safer and less invasive than other methods such as surgery and stent placement. Therefore, it can be the treatment of choice for benign scarring tracheobronchial stenosis caused by various lesions. The disadvantage is that it often needs to be repeated in order to achieve satisfactory results. Balloon dilation of the stenotic airway before stent placement prevents the stent inserter from getting stuck in the stenosis during stent placement and allows the use of a larger stent after dilation, which prevents stent displacement. Balloon dilation alone without stent placement can easily restenose the airway.
(6) Stent placement therapy
The research and application of endoprosthesis technology is becoming more and more widespread, opening up new avenues for the treatment of luminal stenosis or occlusion in the body and achieving significant efficacy, sometimes better than surgery and balloon angioplasty.
Endotracheal stent placement: It is suitable for tracheal stenosis caused by malignant tumor invasion or compression of the trachea, esophagus, and mediastinum; tracheal stent placement can be considered for those who cannot have esophageal stents placed for high esophagus-tracheal fistula.
The placement of the endoprosthesis is simple. The guidewire can be delivered to the intended site under X-ray fluoroscopy or tracheoscopic guidance, and then the endoprosthesis delivery device is placed along the guidewire over the lesion site, and then the endoprosthesis is released at a certain depth to ensure that the endoprosthesis holds up the entire lesion site. If the patient’s condition permits, it is better to have argon knife treatment or photodynamic therapy before the endoprosthesis is placed in order to facilitate tumor control.
Radioactive particles and chemotherapy particles can also be attached to the stent for the purpose of simultaneous radiation/chemotherapy.