[Abstract] Objective To explore the correction of external nasal cartilage cone segment crooked nose caused by basic flat septum but deviated from the midline by nasal endoscopic four-line subtraction method of septoplasty-rhinoplasty. Methods From December 2009 to April 2011, 17 patients with cartilaginous segmental crooked nose and nasal tip deformity caused by nasal septal deviation were selected and classified into 4 types according to the characteristics of square cartilage deviation: square cartilage anterior edge deviation type, nasal tip is crooked to the side of square cartilage deviation; square cartilage anterior-posterior deviation type, external nasal cartilage cone segment is deviated, with obtuse angle to nasal bone, nasal tip is crooked to the side of square cartilage deviation; square cartilage The posterior edge is deviated, the dorsum of the nose is C-shaped or anti-C-shaped distorted; the square cartilage is deviated up and down, the dorsum of the nose is deviated to one side. According to the different types of nasal septal deviation, the corresponding surgical plan was formulated: the connection between the square cartilage and the surrounding bone, cartilage and nasal columella was separated through the intranasal approach under the nasal endoscope, the connection between the square cartilage and the surrounding bone and cartilage was adjusted, and the excess bone or cartilage strips at the connection were removed, i.e., the septoplasty was achieved through the four-line subtraction method of the anterior, inferior, posterior and superior edges of the square cartilage. Results All 17 patients achieved good results, solving the problem of nasal congestion and improving the nasal shape without complications. Conclusion The four-line subtraction method of septoplasty-rhinoplasty under nasal endoscopy can correct the crooked nose caused by square cartilage deviation. [Keywords] endoscopy; otorhinolaryngological surgery; rhinoplasty; nasal septum; four-line subtraction; crooked nose Crooked nose, mostly accompanied by deviated nasal septum, especially cartilage cone deviation, is basically caused by deviated nasal septum. The shape of the nasal septum determines the shape of the nasal bridge. For a crooked nose caused by a deviated septum, it is important to address both the ventilation function and to improve the shape of the external nose. Plastic surgeons and otorhinolaryngology head and neck surgeons have done a lot of work on this and have achieved better results. In cases where the nasal septum cartilage itself is still straight but deviates from the midline and intersects with the posterior septum at an obtuse angle or the anterior lower edge of the nasal septum cartilage is dislocated and causes the cartilaginous segment of the nose to be crooked, the predecessors in the rhinology field corrected the septal deviation, dislocation of the nasal septum cartilage and crooked nose at the same time through the turnstile method of surgery. For those who have a crooked nose caused by the cartilaginous segment of the nasal septum caused by the flatness of the square cartilage itself but the deviation of the connection with the surrounding bones and cartilage and the deformity of the tip of the nose caused by the dislocation of the anterior lower edge of the square cartilage to one side of the nasal cavity, the author further separates the connection of the square cartilage with the cartilage of the nasal dorsum and the nasal columella on the basis of the nasal endoscopic three-line reduction method to correct the nasal septum, and fractures and strips the bones and cartilage of the connection as needed to make the square cartilage The four-line subtraction-replacement method, which is based on further separation of the square cartilage from the dorsal nasal cartilage and nasal columella, fractures and strips of bone and cartilage at the junction as needed, so that the square cartilage dovetails flatly with the surrounding bone and cartilage and resides in the midline. Data and methods I. Clinical data From December 2009 to April 2011, 17 patients aged 16 to 40 years old, all male, were hospitalized in our department with crooked nose and nasal tip deformity of cartilaginous segment caused by deviated nasal septum. Among them, there were 2 cases with poor improvement of nasal ventilation function and shape after traditional submucosal resection of the nasal septum and 5 cases with a clear history of nasal trauma in early childhood or adulthood. II. Methods The surgery was classified according to the deviation of the square cartilage of the nasal septum. 1, anterior edge of square cartilage dislocation: The patient exhibited nasal tip distortion to the side of square cartilage dislocation or even hypoplasia, asymmetric anterior nostrils, and an unequal triangle at the base of the external nasal cone (Figure 1a, 1b-1). 2. Anterior and posterior deviation of square cartilage: the anterior and anterior inferior edges of square cartilage are deviated to one side of the nasal cavity and dislocated, and the posterior edge is deviated to the opposite side and connected to the vertical plate of sieve bone at an obtuse angle, that is, the square cartilage is oblique from front to back. The patient exhibits a crooked nose, i.e. the cartilage cone is deflected in a straight line and connected to the nasal bone at an obtuse angle, and the tip of the nose is deflected to the dislocated side of the anterior edge of the square cartilage (Figure 2a,2b,2c-1). 3. Posterior margin deviation of the square cartilage: the anterior and inferior margins of the square cartilage are not dislocated and flat, but the posterior superior and posterior margins are at an obtuse angle to the vertical plate of the sieve bone, merging or not merging with the bony spine or crest of the maxillary nasal crest. The patient’s nasal dorsum and the obtuse angle of the nasal septum were accordingly in a C-shaped or anti-C-shaped distorted state (Figure 3a). 4. Upper and lower deviation of square cartilage: that is, the dorsal side of the square cartilage is deviated to one side of the nasal cavity while the nasal base is deviated to the other side of the nasal cavity, and the base of the external nasal cone is in an unequal triangle shape. This type of septal deviation combined with crooked nose is mainly caused by trauma in early childhood (Figure 4a,4b,4c-1). 1. Incision: For those who have no dislocation of the anterior edge of the square cartilage, the incision is made in the left nasal cavity, just like the traditional Killian incision. If the anterior edge of the square cartilage is dislocated to one side of the nasal cavity, the incision is always made on the dislocated side and close to the anterior edge of the square cartilage, so that it is easy to push the anterior edge of the square cartilage into the mucosal capsule behind the nasal column, remove the excess mucosa at the incision on that side, and suture the tense mucosal tension of the nasal septum after the incision to fix the anterior edge of the nasal septum in the mucosal capsule behind the nasal column. 2. Separate and adjust the square cartilage from the surrounding bone and cartilage: Separate the mucous cartilage membrane and mucous periosteum on the deviated side, the same as the three-line reduction septum correction surgery, and thoroughly separate the square cartilage from the surrounding cartilage and bone connection. Adjust the connection between the square cartilage and the surrounding bone according to the type of nasal septal deviation. ① For the dislocation of the anterior edge of the square cartilage, the soft tissue behind the nasal columella is separated forward with scissors to form a capsule, and the anterior superior reaches between the medial feet of the greater pterygoid cartilage, the anterior edge of the square cartilage is reset into the capsule behind the nasal columella, and the anterior superior angle is sandwiched between the medial feet of the greater pterygoid cartilage on both sides, so that the lower edge of the square cartilage dovetails flatly with the nasal crest of the maxilla, the excess nasal septal mucosa and mucous cartilage membrane at the posterior edge of the incision is cut off, and the incision is sutured. At this point, the nasal tip is centered, the bilateral anterior nostrils are symmetrical, and the base of the external nasal cone is isosceles triangular. ② For square cartilage anterior-posterior deviation, on the basis of ①, the posterior segment of square cartilage is pushed to the midline from the contralateral nasal cavity so that the square cartilage is connected flatly with the vertical plate of the sieve bone. The whole process is equivalent to freeing the square cartilage sufficiently and turning an angle anterior-posterior so that the nasal septum is vertical and the crooked nose is corrected. ③ For deviated posterior edge of square cartilage, the posterior segment of square cartilage was pushed to the midline from the deviated side so that the square cartilage was connected flatly with the vertical plate of the sieve bone, as in the traditional surgery of turning the door method [8]. ④ For those with upper and lower deviation of the square cartilage, on the basis of ① and ②, the bilateral mucous cartilage membranes on the dorsal side of the nose of the square cartilage were separated, the connection between the dorsal edge of the square cartilage and the dorsal cartilage of the nose was incised, and then the excess medial dorsal cartilage on the wider side of the nasal dorsum was separated and excised in strips, the upper edge of the square cartilage was pushed to the midline position of the lower edge of the nasal bone, and the lower edge was pushed to the midline so that it dovetailed flatly with the surrounding bone, and absorbable sutures were used to fix the upper edge of the square cartilage and The connection between the upper edge of the square cartilage and the dorsal cartilage of the nose is fixed with absorbable sutures. At this point, the nasal septum and crooked nose are corrected (Figure 4D). The whole process is equivalent to turning the square cartilage up and down at an angle. 3. Filling and fixation: Bilateral ventilation tubes were placed in the lower nasal passages, and the septum was fixed by filling the nasal cavity from the bottom to the top of the nose with oil gauze layer by layer for 48 to 72 h. The operation lasted 10 to 40 min, with a median of 30 min. The septum was determined by the operator and another surgeon according to the results of preoperative and postoperative nasal endoscopic examination. Appearance judgment: According to the observation score of patients and family members, there were five levels: -2: significantly worse than before surgery; -1: slightly worse than before surgery; 0: same as before surgery; 1: obvious improvement in appearance; 2: obvious improvement in appearance and basic straightening of nasal bridge. Functional improvement: judged according to the patient’s feeling: significant: all discomfort symptoms before surgery basically disappeared; relatively significant: most of the discomfort symptoms disappeared or significantly reduced. Ineffective: discomfort symptoms were slightly reduced or basically unchanged or even aggravated. Results In 17 patients, both the nasal congestion and the external nasal morphology were significantly improved. No complications were observed. Postoperative appearance score: 2 in 16 cases and 1 in 1 case; degree of postoperative symptom improvement: 15 cases were significant and 2 cases were relatively significant. Discussion Currently, for deviated septum combined with crooked nose, the most commonly used method at home and abroad is to remove the deviated square cartilage and trim it into an L-shaped brace, or to remove the vertical plate of plow bone sieve bone, spread it, reinsert it, and fix it between the dorsal cartilages of the nose to correct the nasal bridge. There are two types of this procedure: external nasal approach and internal nasal approach. In recent years, some authors have also performed simultaneous rhinoplasty on the basis of endoscopic nasal septum correction. In clinical practice we found that a considerable proportion of crooked noses combined with deviated septum of the square cartilage itself is basically flat, the author divided into four types according to the specific situation, and all of them achieve the purpose of septoplasty simultaneous rhinoplasty according to the four-line reduction and repositioning method. The septal deviation consists of the deviation of nasal septal cartilage and bone, most of the septal deviation does not combine the cartilage segment of the crooked nose, only when the anterior segment of the square cartilage to one side of the nasal cavity dislocation or square cartilage is up and down or front and back deviation, making the dorsal edge of the nose out of the midline will cause the cartilage segment of the crooked nose and nasal tip deformity. For the septal deviation combined with cartilage cone distortion, there is a fourth tension zone, which is the connection between the septal cartilage and the nasal dorsal cartilage, the greater wing cartilage and the nasal bone. In this paper, on the basis of the three-line reduction, the tension zone on the upper edge of the square cartilage is also released, i.e. the four-line reduction method. For those who have curved cartilage projection or curved deformity in addition to the deviation of the square cartilage from the surrounding connection, cross resection at the projection or strip resection of the square cartilage at the curvature can be done to straighten it according to the situation. This surgery only removes the excess cartilage strips and bones that affect the septum and nasal cone remodeling without reducing the height of the septum, ensuring the integrity of the bone and cartilage scaffold that supports the nasal shape, and no surgical complications such as stepped nasal bridge or saddle nose will occur if there is no cartilage necrosis caused by infection. No complications occurred in this group of cases. The correction of the third type in this paper, i.e. square cartilage posterior segment deviation, is similar to the traditional surgery of the turnstile method, but this procedure is performed under nasal endoscopy. The indications for this procedure are crooked noses of the conical segment of the external nasal cartilage caused by a basically flat nasal septum but deviating from the midline, so the classification according to the condition of the deviated septum helps to develop the appropriate surgical plan. Pre- and postoperative photographs and surgical pattern of square cartilage anterior edge dislocation crooked nose. a: Pre-operative photograph, bilateral anterior nostrils asymmetrical, nasal tip crooked to the side of square cartilage dislocation, and the base of the external nasal cone in an unequal triangle shape; b: Surgical pattern diagram, 1: pre-operative; 2: surgical procedure: the lower edge of the square cartilage is placed on the maxillary nasal crest, and the anterior superior edge is placed behind the nasal columella and between the medial corners of the bilateral greater pterygoid cartilages; 3: post-operative. c: post-operative. Postoperative photograph, bilateral anterior nostrils are symmetrical, the base of the external nasal cone is isosceles triangular, the nasal septum is straight, and the nasal tip is centered. Square cartilage anterior-posterior deviation with crooked nose preoperative and postoperative photographs, endoscopic images and surgical pattern diagram. a: Preoperative photograph, cartilage cone linearly deviated, connected to the nasal bone at an obtuse angle, nasal tip crooked to the side of square cartilage dislocation (left side); b: Preoperative nasal endoscopic view: square cartilage flat, anterior edge dislocated to the left, posterior edge deviated to the right, forming an obtuse angle with the vertical plate of the septum. 1, nasal septum, 2, inferior turbinate; c: Surgical Schematic diagram, 1: preoperative; 2: surgical procedure with the anterior segment of the square cartilage pushed to the right and the posterior segment pushed to the left and the crooked nose corrected. 3: postoperative. d: postoperative photograph, the patient’s crooked nose corrected and the bridge of the nose straightened. Posterior margin of square cartilage deviated crooked nose surgical pattern Figure a: Posterior margin of square cartilage deviated to form an obtuse angle with the vertical plate of sieve bone; b: Posterior margin of square cartilage pushed to the midline. c: Postoperative. Pre-operative and post-operative photos, nasal endoscopic photos and surgical pattern diagram of square cartilage upper and lower deviations of crooked nose. a: Pre-operative photo, conical segment of nasal cartilage deviated to the right side. b: nasal endoscopic view of square cartilage deviated to the right nasal cavity on the dorsal side and to the left nasal cavity on the nasal base side, 1, nasal septum, 2, inferior turbinate; c: surgical procedure, 1: pre-operative; 2: push the lower edge of square cartilage to the midline and the upper edge to the midline and fix it with sutures to the bilateral dorsal nasal The cartilage was fixed with sutures; 3: postoperative. d: postoperative photograph, the bridge of the nose was straightened and the cartilage tapered segment was basically centered.