The classification of laryngotracheal stenosis is divided into two types by nature, one is congenital or idiopathic stenosis, and the other is acquired stenosis, which can be divided into supraglottic, glottic, infraglottic and transglottic stenosis according to the site of occurrence. The treatment of severe stenosis, in particular, is very complicated and difficult. Since 1994, the authors have been using methods including CO2 laser submucosal vocal fold resection or arytenoid cartilage resection, vocal fold reconstruction, laryngotracheoplasty, anterior cervical rotational myocutaneous flap laryngotracheal reconstruction, laryngotracheotomy with graft reconstruction, tracheal wedge resection or end-to-end anastomosis of the stenotic segment, etc., and have received good results, which are reported below. The results are reported as follows. 1. Data and methods (1) Clinical data: Since 1994, 77 patients with various types of laryngotracheal stenosis were admitted, 45 males and 32 females, aged from 18 months to 69 years old, with an average age of 32.5 years. Causes: 29 cases of trauma (including car accident, axial neck, wire strangulation, fall and others); 43 cases of medical origin, including 2 cases of tracheotomy, 8 cases of thyroid surgery, 33 cases of partial laryngectomy for laryngeal cancer and partial laryngectomy for enlarged laryngeal cancer; 2 cases of chemical burns; 1 case of laryngeal sclerosis; 2 cases of unknown causes. Stenosis sites: supraglottic region in 13 cases, vocal region in 11 cases, subglottic region in 7 cases, transglottic stenosis in 42 cases, and trachea in 4 cases. There were 38 cases with no damage to the skeleton and 39 cases with damage to the skeleton. The degree of stenosis was graded according to Cotton [1]: 3 cases of I° stenosis (lumen narrowing <70%), 45 cases of II° stenosis (lumen narrowing 70%-90%), 24 cases of III° stenosis (lumen narrowing more than 90%), and 5 cases of IV° stenosis (lumen atresia). Among them, 59 cases were treated in other hospitals with different methods of repeated dilatation, laryngectomy laryngeal membrane expansion, hyoid bone flap grafting, surgical scar excision, and placement of memory metal stents and other reconstructive procedures. (2) Treatment methods The following reconstruction methods were mainly used according to different sites and degrees of stenosis CO2 laser surgery: It is mainly suitable for small vocal fold type scar stenosis, and thin congenital laryngeal webs are the most ideal candidates for laser treatment. It is also suitable for patients with bilateral vocal fold abduction paralysis. The procedure is performed under general anesthesia microscope, using 8-10W, 0.1s low-power pulsed laser to vaporize or cut the laryngeal web or adhesive band, or to remove the submucosa of the completely paralyzed side of the vocal folds, or to vaporize the arytenoid cartilage with 15-20W continuous pulses and partially remove it. The procedure is simple. Vocal hilar reconstruction: It is suitable for patients with simple vocal hilar scar stenosis or bilateral vocal fold paralysis. Under direct vision, the submucosa of the larynx is opened to remove the arytenoid cartilage on one side, and the vocal cords are excised under the mucosa, and the vocal cords are sutured externally to enlarge the vocal folds as much as possible, and no support is placed if there is no scar tissue. If there is scar tissue in the interarytenoid area, the scar tissue will be cut away and the surrounding mucosal flap will be taken and transplanted in the interarytenoid area, and then a T-tube support will be placed. Laryngotracheoplasty: For supraglottic, glottic, subglottic or mixed laryngeal stenosis with intact or less defective laryngeal cartilage support. The laryngeal lumen is split medially in the neck and the scar tissue of the stenotic laryngeal lumen is removed under direct vision, and submucosal scar resection is feasible for less severe stenosis. The laryngeal cavity is enlarged as much as possible during surgery, and a dilator is placed in the laryngeal cavity, usually for 3 to 6 months, and then removed after epithelialization of the trauma. Most laryngeal dilators are T-tubes. In subglottic area and cervical tracheal stenosis, mild cases without cartilage defects can be repaired by submucosal excision of the scar and "Z" shaped incision of the mucosa; in severe cases, grafts should be used. Anterior cervical rotating myocutaneous flap laryngotracheal reconstruction: It is mainly suitable for laryngeal stenosis after partial laryngectomy and extended partial laryngectomy for all types of laryngeal cancer, but also for other types of patients with urgent desire for extubation. The myocutaneous flap is taken as a triangular or oval shape, equal to the defective laryngeal cavity. The muscle is separated in the deep layer of the sternocleidomastoid fascia, and the two muscle tips are free in such a way that the flap can be turned into the laryngeal cavity to completely cover the defect cavity. After the myocutaneous flap is made, a suture is placed at the turning point equivalent to the anterior union and the laryngeal chambers, and a knot is pulled out of the skin when the laryngeal cavity is closed to form the anterior union and the new laryngeal chambers to prevent laryngeal stenosis. If a triangular myocutaneous flap is repaired, its tip is cut off and turned toward the laryngeal cavity so that the skin surface faces the laryngeal cavity, and each side is sutured accordingly to close the laryngeal cavity. Postoperatively, there is usually no need to place a support. However, those who have undergone bilateral neck contouring, bilateral sternoglossal muscle severance, local recurrence of tumor, and those who have less than 6 months from the end of radiotherapy are considered as contraindications to surgery. Laryngotracheotomy implantation graft: It is suitable for laryngotracheal stenosis or atresia in various parts with skeletal defects. The laryngeal trachea is split and the scar tissue is excised under the mucosa, and different graft materials are selected according to the size and location of the defect. Autologous grafts include tipped hyoid flap, rib cartilage flap, and sternocleidomastoid periosteal flap. Synthetic materials include memory metal titanium stents, which are placed into T-tubes for support. Tracheal wedge resection or stenosis segmental resection end anastomosis: tracheal wedge resection is suitable for stenosis located at or above the tracheotomy site, and the length of stenosis does not exceed 1.5 cm. Stenosis segmental resection end anastomosis is mainly suitable for cervical segmental tracheal stenosis length not exceeding 5 cm. 2. Results CO2 laser microlaryngoscopy was performed in 5 cases, and 4 cases (80.0%) were cured at one time, 1 case (20%) was cured at a second time. ), with an overall cure rate of 100%. Vocal hilar reconstruction was performed in 11 cases, 10 cases were cured at one time and 1 case was lost, with a cure rate of 90.91%. Laryngotracheoplasty was performed in 13 cases, 11 cases were cured once, 1 case was cured twice, 1 case was not cured, the overall cure rate was 92.31%, and the average time with T-tube was 1.2 years. There were 40 cases of laryngotracheal reconstruction with anterior cervical rotary flap, 35 cases were cured and extubated once, 2 cases were cured and extubated twice, 2 cases were not cured, 1 case was lost due to family relocation, and the overall cure rate was 92.50%. The average with T-tube 1 year. There were 9 cases of laryngotracheotomy implantation grafts, 1 case did not heal, the cure rate was 88.89%, including 1 case with memory alloy stent, 8 cases with rib cartilage, hyoid bone, sternoclavicular lingual muscle flap, etc., the average with T-tube 5.5 months. Two cases were cured by wedge resection of trachea and two cases were cured by end-to-end anastomosis of stenotic segment. Of the 77 cases, 6 cases were not cured (including lost visits), 71 cases (92.21%) were cured by extubation, 75 cases were followed up for 1-10 years, and 4 cases were cured by reoperation after reappearance of stenosis 1 to 3 years after surgery. 3. Discussion Laryngotracheal stenosis is one of the difficult diseases in clinical laryngology, especially extensive cartilage defects, circumferential stenosis, and long stenosis, although there are many reconstruction methods with different long-term outcomes. The diagnosis of laryngeal stenosis includes determining the site, length, and extent of obstruction and associated complex lesions such as vocal cord paralysis, tracheal softening, and tracheoesophageal fistula. Surgery for laryngotracheal stenosis involves two aspects: on the one hand, the effective lumen is enlarged by excision of the scar and covering the wound with mucosal and skin flaps to prevent granulation and scar growth; on the other hand, the integrity of the laryngeal stent is restored to reduce the collapse of the airway due to negative pressure during inspiration and compression by soft tissue and scar outside the laryngeal trachea, or the diameter of the laryngeal stent is increased to counteract the narrowing of the airway due to scar growth in the larynx. For those with limited scarring, scar excision must be complete up to normal soft tissue, and scar excision must be submucosal to preserve as much normal mucosal tissue as possible; most wounds can be directly sutured after submucosal subtle separation. For more severe stenosis or even atresia, it is difficult to remove all the scar tissue, so the scar at the heavier stenosis can be removed and the existing scar can be used as part of the airway stent to expand the airway by widening and deepening the laryngeal tracheal stent. The CO2 laser microlaryngoscopic surgery for laryngeal stenosis has yielded more satisfactory results, which may be related to the severity of the condition. We treated 4 patients with bilateral vocal fold adductor paralysis after thyroid surgery. In 3 cases, tracheotomy was performed at the time of admission, and the mucosa of one vocal fold was incised by intubating anesthesia from the tracheotomy, and the vocal fold was vaporized by using 8-10W, 0.1s low-power pulsed laser, and the mucosal flap was repositioned and glued with bioprotein glue with good results. In another case, partial excision of the arytenoid cartilage was performed by nasal cannula, and the latter was later followed by partial excision of the vocal folds. 1 case was excised for laryngeal web formation. The prevention of postoperative granulation obstructing the airway or posterior laryngeal web formation is the key to this type of surgery, on the other hand, the laser operation should usually not exceed 15 minutes to reduce its thermal effect. For subglottic tracheal stenosis may be more difficult to treat because of its limited exposure and the number of cases treated is still small and needs to be further summarized. The cure rate of vocal hilar reconstruction and laryngotracheotomy scar tissue excision and reconstruction is higher, also related to the severity of the disease. Since 1994, our department has applied the anterior cervical rotary myocutaneous flap laryngotracheal reconstruction and obtained satisfactory results. The rotating myocutaneous flap has good blood flow, high survival rate, blood supply mainly from the supraglottic artery, flexible and convenient sampling, little injury, and good support in the same surgical area with laryngectomy. The myocutaneous flap has certain tension and strength, which can effectively replace the arytenoid cartilage and vocal cords, and the surface of the reconstructed laryngeal cavity is smooth, and the skin surface faces the laryngeal cavity after surgery, which is not easy to grow granulation. The following issues should be noted during surgery: make the myocutaneous flap as wide as possible to ensure the spaciousness of the reconstructed laryngeal cavity, do not separate the skin from the muscle when making the flap to avoid affecting the blood flow of the flap, and do not make the anastomosis under too much tension when closing the laryngeal cavity to avoid affecting the healing. The application of rotary muscle flap for laryngeal reconstruction can enable people who have been carrying a tube for a long time after partial laryngectomy to remove the tracheal tube and regain the function of breathing through the mouth and nose and normal neck appearance and satisfactory functional results of pronunciation and swallowing protection. The sternocleidomastoid periosteal flap is mainly used for the repair of subglottic and tracheal stenosis. When cutting the periosteal flap, the surface soft tissue should be preserved as much as possible, the sternocleidomastoid muscle should not be freed excessively, and the blood supply vessels of this muscle should be protected, the tipped periosteal flap has good blood supply and is not easy to be infected and necrotic, and the bone can be generated after the distant periosteal flap transplantation. The hyoid flap graft with tip has a muscular tip, good blood supply, and can be used without a supporter, but the hyoid bone is hard and cannot be easily sutured to cartilage, so it often fails after surgery due to displacement. Free rib cartilage can be firmly sutured to the cartilage, and expansion subs can also be applied, but incisions have to be made on the chest, and the rib cartilage is prone to ischemic necrosis and is less resistant to infection. Memory titanium metal stent can play a good supporting role, but it is easy to have granulation tissue regeneration after surgery, and benign disease should be more cautious. Tracheal stenosis should be treated according to its narrowing site and length to determine the treatment method. During surgery, we should try to avoid damaging the blood vessels on both sides of the trachea, protect the laryngeal nerve in the paratracheal fascia, and keep the head in forward flexion for 10-20° for 2 weeks after surgery. During the treatment of this group of cases, sufficient attention was paid to cover the trauma, no postoperative growth of granulation, shortened extubation time, multiple methods were used during surgery, and the reconstruction of the laryngotracheal stent was emphasized, and the reconstructed laryngeal cavity was spacious enough, so the cure rate of this group was higher and the treatment period was significantly shortened compared with other domestic and foreign scholars' reports.