The self-retaining laryngoscope was advocated by Kleinsasser (1968). We have been using this technique since the early 1980s to treat and diagnose laryngeal diseases. In the early days, we mainly treated vocal fold polyps, vocal fold nodules and performed laryngeal biopsies, but now we mainly perform broad-based or refractory vocal fold polyps or early laryngeal cancer, pre-cancerous lesions, laser surgery, voice surgery, etc. I. General introduction Although several types of support laryngoscopes have been replaced from the 1980s to the present, the basic structure of the support laryngoscope is the same. It consists of 3 parts: direct laryngoscope, connecting part and supporting frame. The direct laryngoscope has an oval shape at the proximal end with a large cross diameter and a rounded front end, with different sizes available depending on the patient’s body shape. There is an opening on each side of the tube wall for inserting a cold light source wick on one side, and for inserting a suction tube or spraying oxygen on the other side. The upper end has a straight handle, and the handle end can be tightly connected to the connection part by bolts. The support frame has two parts, one is a 500mm long support rod, the other is located at one end, the rotatable chest pad plate, the support rod can be inserted into the connecting part. The angle between the brace and the shank is continuously adjusted to fully expose the acoustic canal, etc., by means of an adjustment screw in the connecting section during examination or surgery. To reduce postoperative chest wall discomfort, a thicker book is usually placed between the chest pad and the chest wall to distribute the pressure. The reason why the support laryngoscope occupies an important place in the diagnosis and treatment of laryngeal diseases is that it frees the operator’s hands, which facilitates the intra-laryngeal examination and surgical operation. In particular, it facilitates the use of surgical microscope, which makes laryngeal surgery clearer, more precise, safer, easier to teach, etc. The microscope mostly adopts binocular operating microscope, whose construction is similar to otologic operating microscope, but the focal length of objective lens is 350-400mm, which is longer than otologic microscope. It can be magnified 6-40 times, and generally magnified 10 times. The surgical microscope can be equipped with a photographic connection hole or video connection hole, which is convenient for teaching and preservation of clinical data. Binocular observation and two-handed operation under the microscope and microsurgery with the matching microsurgical instruments have brought the rough laryngeal surgery under direct laryngoscope to an important stage. Of course, for simple vocal cord diseases that are clearly observed under the naked eye, it is not necessary to operate under the microscope for all of them, which can save the operation time and reduce the patient’s expenses. Microscopic laryngeal surgical instruments: including various types of laryngeal forceps, laryngeal scissors and laryngeal syringes that open to the left, right and above. Surgical indications for supported laryngoscopy: 1. Biopsy of larynx and laryngopharynx The supported laryngoscope can better expose the larynx and laryngopharynx, so diseases located in this area need biopsy, especially submucosal lesions, and this method can be used. 2.General supported laryngoscopy For more limited benign and malignant proliferative diseases located in this area such as: vocal fold polyps, vocal fold nodules, laryngeal papilloma, vocal fold leukoplakia, etc. For patients who cannot be examined or operated by indirect laryngoscope or fiberoptic laryngoscope, and for patients with high articulation requirements who suffer from vocal fold polyps and nodules. 3.Laryngeal microlaser surgery T1-2 early laryngeal cancer, laryngeal papilloma, hemangioma, limited laryngeal stenosis, vocal fold adhesions, arytenoid cartilage resection, etc., with laser, microwave, electrocoagulation treatment, etc. 4.Laryngeal microinjection Vocal cord paralysis, vocal cord atrophy, vocal cord sulcus, incomplete vocal cord closure, chronic inflammatory disease of vocal cord, laryngeal foreign body, special laryngeal injection, etc. Third, support laryngoscopy surgery contraindications: support laryngoscopy is mostly a relative contraindication for patients with poor general condition such as: serious illness, highly debilitated, hypertension, heart disease, cerebrovascular had outside the patient; for patients with difficulties in exposure such as: cervical spine pathology, deformity, small jaw, short obese neck, too long upper incisors, etc. All those who cannot tolerate general anesthesia surgery. Although not absolutely contraindicated, great caution is needed. Those who can solve the problem by other methods, such as electronic laryngoscopy and fiberoptic laryngoscopy, should not be forced. If you must do it, you should be fully prepared and obtain the understanding and cooperation of the patient and family. Surgical method: The patient is placed in a flat supine position, with padding under the shoulder. The operator holds the mirror in the left hand and puts a layer of thick gauze to protect the upper teeth. The upper lip is pushed away with the index finger of the right hand to avoid injury by the mirror pressing on the teeth. The laryngoscope is fed into the mouth along the central incisors, and the root of the tongue is gently pressed upward, slowly entering the mirror inward. When the epiglottis is seen from the laryngoscope, continue to penetrate 1 cm deeper, and after crossing the free edge of the epiglottis, the left hand picks up the epiglottis with parallel upward force to expose the vocal hilum, and the ideal result is a good exposure of the anterior coalition and the extent of the lesion. At this point, a supporter can be attached and a chest pad plate placed to fix the supporting laryngoscope, and then the position of the operating microscope can be adjusted appropriately according to the focal length to see the laryngeal cavity structure through the eyepiece and operate with both hands. When there is difficulty in exposure, the following points are worth noting: 1. Do not use the upper incisors as the fulcrum when exposing, but use the combined force of both hands to lift the epiglottis; 2. Do not lift the larynx too much, because too much will damage the laryngoscope and strain the patient’s pharynx, and the patient feels sore after surgery. The support frame should be fixed after partial exposure, and then adjust the spiral to lift the anterior part of the laryngoscope after a few moments; 3. Expose the voice box while the assistant gently presses down on the thyroid cartilage, or adjust the patient’s position; 4. 30o and 70o nasal endoscopes can be borrowed to observe the voice box and subsound box; 5. Replace the appropriate laryngoscope. V. Anesthesia methods: Support laryngoscopy is usually performed under general anesthesia. That is, intravenous anesthesia and endotracheal intubation anesthesia, both intraoperative muscle relaxants are required to relax the muscles to ensure satisfactory visualization of the laryngeal cavity with control of the opening of the vocal folds. It should be mentioned that good cooperation of the anesthesiologist is the key to successful laryngeal microsurgery. There are 3 types of anesthesia methods: 1. Cricothyroid membrane puncture with insertion of ventilation needle anesthesia: This method is easy to puncture, reliable needle insertion, no intubation in the larynx, and large surgical field. It facilitates surgical operation, but if the ventilation needle is unstably fixed or laryngeal spasm leads to vocal fold closure, it can cause subcutaneous and mediastinal emphysema, and even cause pneumothorax. Now it has been abandoned. 2.High-frequency jet anesthesia: Insert a plastic tube with a diameter of about 5mm (ordinary suction tube) through the nasal cavity to the subsonic valve (blind insertion or intubation forceps to send the catheter to the subsonic valve), connect the catheter to a high-frequency jet ventilator, then start general anesthesia and control breathing with high-frequency jet ventilation. Since the transnasal cannula does not occupy the oral space and the tube is thin and soft at the posterior part of the vocal cords, it does not block the operative field when inserting the support laryngoscope, which facilitates the surgical operation. General anesthesia high-frequency jet ventilation has the characteristics of good ventilation effect, low airway pressure, clear visibility of the operative field, and easy awakening after surgery, which basically meet the requirements of vocal cord surgery. The author has summarized a total of 820 cases of high-frequency jet anesthesia vocal cord surgery performed in our hospital from March 1985 to December 1996. Among them, 585 cases were male and 235 cases were female, aged 17-85 years old, average 42 years old; 522 cases were bilateral vocal fold polyps, 134 cases were unilateral vocal fold polyps; 96 cases were vocal fold nodules, 17 cases were vocal fold leukoplakia, and 12 cases were vocal fold cysts. 17 cases, and 12 cases of vocal fold cysts. There were 10 cases of vocal fold closure insufficiency (paraffin oil injection), 10 cases of laryngeal neoplastic biopsy, 8 cases of laryngeal papilloma and 11 cases of others. (1) Anesthesia method Half an hour before surgery, atropine 0.5mg and phenobarbital 0.1g were injected intramuscularly. 1% dicaine or 2% lidocaine 2ml was administered as endotracheal surface anesthesia for cricothyroid puncture. After the patient’s consciousness is reduced, a thin plastic tube (ordinary aspiration tube) is inserted through the nostril, the epiglottis and vocal hilum are exposed with a laryngoscope, a small amount of dacronin is sprayed, and the catheter is delivered under the vocal hilum by blind insertion or intubation forceps. The catheter is connected to a high-frequency jet ventilator, and low-pressure high-frequency jet ventilation is started, with good breath sounds in both lungs on auscultation, and the catheter is fixed. Before inserting the support laryngoscope, inject thiopental sodium 5mg/kg and succinylcholine 1mg/kg sedatively while turning up the oxygen pressure (0.5-1kg). If the operation time is longer, the same intravenous anesthetic can be increased in appropriate amount, and blood gas can be checked to understand the partial pressure of carbon dioxide and adjust the oxygen pressure. After the surgery, reduce the oxygen pressure and remove the catheter, monitor the blood pressure, ECG and oxygen saturation, and send the patient back to the ward after satisfaction. For some patients who want to perform fine surgery, they need to be operated under the operating microscope, but the operation time is relatively longer. There were 300 cases of microscopic surgery in this group. (2) Results Among the 820 cases, 40 cases were endotracheal ventilation via cricothyroid membrane puncture, and 2 cases of subcutaneous emphysema occurred, one of which was complicated by mediastinal emphysema. The remaining cases were intubated via the nasal cavity and no further emphysema occurred; 12 cases were difficult to intubate and the intubation time exceeded half an hour, and one of them induced asphyxia during intubation. Intraoperative vocal fold exposure difficulties (the anterior union could not be displayed) were observed in 30 cases, 25 cases required reoperation for incomplete removal of the lesion, 18 cases had recurrence of vocal fold polyps after surgery, 40 cases had transient phlebitis after surgery, which was cured by physiotherapy and local heat application. 20 patients had recalcitrant eruption within 1-3 days after surgery, which gradually stopped after intramuscular injection of Valium, Gastroflucan and Ritalin. The patients had a preoperative sound time of 4-15 seconds, with a mean of 7 seconds, and a postoperative sound time of 10-41 seconds, with a mean of 16 seconds, the day after surgery. By t-test, p<0.01, the difference was very significant. (3) Discussion With the development of fiberoptic laryngoscopy technology, there have been many vocal cord disorders that would have been operated under general anesthesia supported laryngoscopy or direct laryngoscopy that can be changed to epi-anesthesia fiberoptic laryngoscopy. However, there are still some complex cases that need to be performed under general anesthesia-supported laryngoscopy. In the early stage of this group, simple vocal fold polyps and vocal fold nodules accounted for most of the cases, but in the later stage, most of the cases were those that could not be removed by outpatient fiberoptic laryngoscopy or could not be completely removed, such as broad-based polyps, bilateral lesions close to the anterior union, and submucosal lesions. Therefore, the requirement for general anesthesia is higher. If the anesthesia is satisfactory, the field is clear, and the vocal cords do not move during the surgery, the polyps or nodules are removed quickly and well. Even if some new laryngeal organisms need to be observed or biopsied, the operation is not too difficult. The operation time of this group (from the insertion to the exit of the supporting laryngoscope) was 5-60 minutes, with an average of 15 minutes, which can be called "small operation with big anesthesia". Those with long operating time were those with poor anterior union exposure and bilateral lesions requiring microscopic surgery. Although the microscope can improve the accuracy of vocal fold surgery, it is not routinely used in our hospital because of the lack of time and financial burden on patients with well-exposed and clear surrounding lesions. Some special patients such as obesity, short neck, cervical ankylosis, epiglottis curl, and laryngeal neoplasia have difficulty in placing high-frequency ventilation tubes with the help of fiberoptic bronchoscopy. Placement of the ventilation tube under the voice box is a prerequisite for the safe completion of this procedure to prevent accidental insertion into the esophagus. The support laryngoscope can be traced to expose the vocal canal by picking up the epiglottis, and as long as it is present, laryngospasm is easily managed. The method of percutaneous endotracheal ventilation is eliminated because it does not solve the problem of access to air in laryngospasm. Prevention of laryngospasm requires attention to adequate laryngeal anesthesia and avoiding roughness during surgery. It is not necessary to force some patients who have difficulty in fully exposing the vocal cords intraoperatively and to remove as much abnormal tissue as possible and not to operate blindly to avoid complications. The lesions that are not completely done by support laryngoscopy can be compensated by fiberoptic laryngoscopy or indirect laryngoscopy, and 25 such patients have been compensated with more satisfactory results. The use of jet oxygen for ventilation through a small catheter was first introduced by Sanders (1967), and this principle was successfully applied to laryngoscopy under general anesthesia. After experimental and clinical studies, it was found that this method has the advantages of good ventilation effect, light circulatory disturbance, clear operative field and is conducive to surgery. The effect on airway pressure, ventilation volume, blood gas and circulation mainly depends on the choice of ventilation parameters and the resulting ventilation effect, of which the choice of frequency is particularly important. The faster the frequency the higher the partial pressure of oxygen and the higher the partial pressure of carbon dioxide, which is due to the short inspiratory and expiratory phases per unit of time and insufficient expiration, which reduces the effectiveness of gas exchange, so the frequency should be maintained at 60-100 times/min. Vocal cord surgery is operated in the open airway state, and jet ventilation can still maintain normal gas exchange. The method produces lower airway pressure and therefore reduces the adverse circulatory effects of artificial ventilation. It is not antagonistic to spontaneous breathing and is easily synchronized or collocated, so it allows for not only artificially controlled breathing but also artificially assisted breathing. When the operation is prolonged, despite normal arterial partial pressure of oxygen and oxygen saturation, arterial partial pressure of carbon dioxide is often reduced or too high due to over- or under-ventilation, which should be corrected promptly by checking blood gases. Repeated deepening of anesthesia can delay the recovery of consciousness, and the degradation products of some drugs still have certain pharmacological effects and can accumulate in the brain and have a suppressive effect on the postoperative period. Therefore, medium- and short-acting nondepolarizing inotropic agents such as atracurium and mevisone can be considered for patients with estimated long operative times. Since the use of isoproterenol instead of thiopental sodium, the patient's postoperative recovery time has become shorter, and the onset of anesthesia is fast, and the repeated use of less accumulation, is currently the ideal intravenous anesthetic for vocal cord surgery. 3, general anesthesia with tracheal intubation: the main feature of supported laryngoscopic surgery is that the operator and the anesthesiologist share an airway. In order to avoid intubation affecting the surgical line of sight, it is required to choose a tracheal intubation tube with a diameter of 6mm with a balloon. Breathing is controlled by a conventional ventilator, which ensures unobstructed breathing and good gas exchange. This method has the ability to deepen the depth of anesthesia, reduce the CO2 accumulation due to the long operation time, and available inhalation anesthetics. However, its disadvantage is that it sometimes affects the exposure of the vocal cords and the lesion site. Some surgical techniques: 1, vocal folds completely immobile surgery, so the anesthesia requirements are higher. 2. Vocal fold polyps or nodules can be pulled out first with forceps and removed at the base with forceps or knife in the direction parallel to the vocal folds. 3. Bilateral lesions close to the anterior union can be operated in stages, a stage of surgery with the help of a microscope, to ensure that the anterior union has part of the mucosal epithelium is not damaged, can do a "paper folding action", so that the mucosa does not pull to the opposite vocal cord mucosa. 4.Vocal cord cyst: cut open the surface of the cystic mucosa with a knife, separate the tissue around the cyst with a stripper, remove the cyst completely and reset the separated mucosa. 5. Vocal fold edema-like hypertrophy: cut open the surface of the edema mucosa with a knife or needle first, repeatedly attract the mucosa and submucosa with a suction device in the area of edema, and then finely remove the obvious raised mucosa and submucosa tissue, the principle is "rather right than left", after the operation can be observed or remedied by other methods, and inject long-acting hormone under the mucosa during the operation. If more is removed, it may affect the patient's postoperative pronunciation. 6.Laser surgery: Ventilator with air to maintain ventilation can prevent the introduction of gas tube cannula. 7.When there is difficulty in judging the scope of early laryngeal cancer, a little saline can be injected locally and the tumor site will not bulge with the water injection. VII. Complications of supported laryngoscopy: 1. Cardiac complications Strong reported that among 711 general anesthesia supported laryngoscopies performed on 540 patients aged 35-87 years, cardiac complications occurred in 19 cases (3.5%). Methods to prevent cardiac complications: intraoperative cardiac monitoring, oxygen saturation monitoring, gentle intraoperative operation, and still perform cardiac monitoring for a period of time after surgery if necessary. 2, complications caused by general anesthesia 3, oropharyngeal complications Tooth loss, soft palate injury. Numbness of the tongue, loss of taste sensation, etc. 4.Laryngeal complications Vocal cord adhesions, vocal fold granuloma, neoplastic residue, incomplete vocal fold closure, no improvement in pronunciation after surgery. VIII. Comparison of supported laryngoscope with electronic laryngoscope and fiberoptic laryngoscope: Electronic laryngoscope and fiberoptic laryngoscope are basically the same surgical method, and in the following comparison, these two are regarded as one method. The following is a summary of our experience with these two procedures and the problems revealed by the changes in the number of their procedures over the past decade or so. 1. Clinical data From January 1985 to July 1999, a total of 1976 cases of vocal fold polyps and small nodules were performed under fiberoptic laryngoscopy, including 1182 cases of vocal fold polyps and 794 cases of small nodules. 22.3 cases per year on average were performed before 1993 and 256.9 cases per year after 1993. A total of 887 cases of laryngoscopic vocal fold polyp and vocal fold nodule surgery were performed during this period, including 678 vocal fold polyps and 209 vocal fold nodules. 72.9 cases were performed on average per year before 1993 and 43.4 cases per year after 1993. Of all 2863 cases, 1775 were male and 1088 were female; age ranged from 9 to 82 years, with an average of 40.7 years. The number of vocal fold nodules and vocal fold polyps performed under fiberoptic laryngoscopy and supported laryngoscopy in the past years is shown in the attached figure. 2. Methods All fiberoptic laryngoscopic procedures were performed by transnasal and laryngeal surface anesthesia. Before '93, the pharyngeal and laryngeal anesthesia was performed by spraying the pharynx and larynx with 1% dacronin solution three times, then injecting 1-2 ml of 1% dicaine into the larynx with a dropper, and for those sensitive to the laryngeal reflex, 1 ml of 1% dicaine could be injected through the biopsy hole of the mirror; after '93, all pharyngeal and laryngeal anesthesia was performed with the multi-effect gastroscopic gel developed by our hospital, and then injecting 1% dicaine under the cricothyroid membrane. After completion of superficial anesthesia, the fiberoptic laryngoscope was introduced into the laryngeal vestibule through the nasal cavity to examine the lesion, and the biopsy forceps were introduced by the assistant, and the forceps were opened when the polyp or node was approached, and the polyp or node was clamped under the instructions of the examiner or under the guidance of the TV screen. All supported laryngoscopy procedures are performed under general anesthesia and high-frequency jet ventilation. The support laryngoscope was inserted through the mouth, the epiglottis was picked up, the support laryngoscope was fixed, the vocal fold lesion was examined, and the lesion was removed naked-eye or under a microscope. 3. Results: 957 cases (81.0%) of vocal fold polyps were removed under fiberoptic laryngoscope for one time (957/1182), 142 cases (12.0%) of vocal fold polyps were removed for two times (142/1182), and 83 cases (7.0%) of polyps could not be removed effectively and required laryngoscopic support surgery (83/1182). There were 738 cases or 92.9% (738/794) who had their vocal fold nodules removed once under fiberoptic laryngoscopy, 40 cases or 5.0% (40/794) who had their vocal fold nodules removed twice, and 16 cases or 2.0% (16/794) who could not have their vocal fold nodules removed. There were 637 cases (94.0% (637/678)) of laryngoscopically supported vocal fold polyps removed once, 34 cases (mostly bilateral or near the anterior union) of vocal fold polyps removed twice (5.0% (34/678)), and 7 cases (1.0% (7/678)) of vocal fold polyps could not be removed effectively. One time removal of vocal fold nodules under support laryngoscopy was performed in 209 cases, accounting for 100% (209/209). With fiberoptic laryngoscopic surgery, there were no complications except for incomplete removal of vocal fold nodules or polyps. There were 40 cases of transient phlebitis after support laryngoscopy, which was cured by physiotherapy and local heat application; 22 cases of intractable erratic reflux occurred within 1-3 days after surgery, which was gradually stopped by intramuscular injection of Valium, Gastroflucan and Ritalin. There were 120 cases of intraoperative soft palate injury, mostly due to local tension and strain when exposing the vocal cords. 4. Discussion Removal of vocal fold nodules and polyps under fiberoptic laryngoscope has the advantages of good exposure, clear vision, fine operation and less pain for patients than traditional indirect laryngoscope or direct laryngoscope removal. It is safer, easier, more economical, and free of side injuries and complications than laryngoscopic surgery supported by general anesthesia. The widespread development of this procedure is attributed to the improvement of surface anesthesia methods in the larynx and the advancement of fiberoptic laryngoscopy equipment. 93 years ago, this technique was constrained by unsatisfactory traditional surface anesthesia methods and passive clamping of polyps by assistants. Although our hospital was equipped with fiberoptic laryngoscopes as early as the late 1970s, most of them were used only for examination, and from '85 to '93, an average of 22.3 procedures were performed each year. After 93 years, with the use of multi-effect gastroscope glue and 1% dicaine subcircumferential injection, the problem of surface anesthesia in fiber laryngoscopy was basically solved, and the fiber laryngoscope was also equipped with TV imaging system, so that the operator and the assistant could cooperate more closely during the operation. The cooperation between the operator and the assistant during the operation is much closer. As a result of these two technological advances, fiberoptic laryngoscopy has become increasingly popular in outpatient clinics, with an average annual volume of 256.9 procedures, while the annual volume of general anesthesia-supported laryngoscopy has decreased to 43.4 procedures. Although the fiberoptic laryngoscope has the advantages of good illumination, clear image and random bendability of the hose body, which makes the operation convenient and less painful for patients, and is especially suitable for children, the narrow cavity of the mirror limits the caliber of its biopsy forceps, so the operation is only suitable for smaller lesions such as vocal cord nodules and small polyps with narrow tips, etc. Although the annual number of supported laryngoscope operations has decreased since 1993, the difficulty of the required operations has increased. Most of them are broad-based, larger polyps. Only 39 cases of small vocal cord polyps were performed in 7 years, all of them were unwilling to operate in outpatient clinics or could not tolerate episodic surgery. Supported laryngoscopic surgery, although it requires general anesthesia, is costly and painful for the patient, and has some postoperative complications, but it is also unique. It allows complete removal of large vocal fold polyps and performs more complex vocal fold surgery with a high success rate in a single operation, is not affected by the patient's gag reflex, and does not require the patient's cooperation. Under the microscope, it can be operated with both hands and is better for bilateral lesions, anterior union lesions, and bleeding-prone lesions. However, this technique has not progressed much in recent years. The changing numbers of small nodules and polyps in the vocal cords operated by fiberoptic laryngoscopy and supported laryngoscopy show that fiberoptic laryngoscopy is playing an increasing role. For smaller lesions of the vocal cords, fiberoptic laryngoscopy will gradually replace the support laryngoscope, and for larger lesions, it is still mainly supported laryngoscopy, but this is the direction that fiberoptic laryngoscopy technology needs to work.