【Abstract】Objective: To summarize the clinical application of revealed laryngeal nerve (RLN) in thyroid surgery. METHODS: 289 cases of thyroid surgery patients were randomly divided into the revealed RLN group and the non-revealed RLN group, and the results of RLN injury in the two groups were analyzed against each other. RESULTS: There was one case of temporary RLN injury in the revealed RLN group, with an injury rate of 0.63% (1/158) and no permanent injury; there were nine cases of temporary RLN injury in the non-revealed RLN group, with an injury rate of 6.87% (9/131), and there was one case of permanent RLN injury, with an injury rate of 0.76% (1/131), and the rate of RLN injury in the revealed RLN group was significantly lower than that in the non-revealed RLN group (P <0.05). CONCLUSION: Exposing RLN in thyroid surgery can effectively protect and reduce injury, which is worth promoting clinical application. With the incidence of thyroid disease increasing year by year, the need for thyroidectomy surgery increased, and some primary hospitals for the first time the scope of surgery is not enough to require a second, multiple surgeries, due to the anatomical structure of the unclear, tissue adhesions and so on is very easy to lead to laryngeal nerve injury, according to the statistics, thyroid surgery laryngeal recurrent nerve (RLN) injury rate of 0.8% to 9.5% [1-3], unilateral RLN injury caused hoarseness, pitch reduction or even loss of voice, and bilateral RLN injury results in bilateral vocal fold gap narrowing and death by severe asphyxiation. To explore the effective reduction of RLN injury during thyroid surgery, the author retrospectively analyzed 289 cases of RLN injury during thyroid surgery in our department from July 2008 to December 2013, which is now reported as follows: 1. Data and Methods 1.1 General Information The whole group of 289 patients, 107 male and 182 female, with an average age of 46.5 (15-84) years, were randomly divided into the The patients were randomly divided into two groups: the exposed RLN group and the non-exposed RLN group, of which 158 cases were in the exposed RLN group, with 61 males and 97 females. There were 130 cases of benign lesions, including 32 cases of thyroid adenomas, 79 cases of nodular goiter, 19 cases of hyperthyroidism, and 28 cases of thyroid cancer; 131 cases of initial surgery and 27 cases of reoperation. There were 131 cases in the non-explicit RLN group, 46 males and 85 females. There were 114 cases of benign lesions, including 38 cases of thyroid adenoma, 61 cases of nodular goiter, 15 cases of hyperthyroidism, and 17 cases of thyroid cancer; 98 cases of initial surgery and 33 cases of reoperation. Comprehensive preoperative examinations were performed, including heart, lung, liver, kidney, and other important organ function tests. Preoperative laryngoscopy were routinely performed to check the normal function of the vocal cords, no paralysis, if the preoperative diagnosis is not clear, should be prepared for intraoperative frozen pathology examination; strictly grasp the indications for surgery, no contraindications to surgery. 1.2 Methods 1.2.1 Anesthesia The patients were all intubated under general anesthesia with disposable double-tube laryngeal mask (supreme laryngeal mask airway, SLMA). 1.2.2 Surgical methods There were 32 cases of thyroid adenomectomy in the exposed RLN group, 98 cases of thyroidectomy for most of the thyroid gland, 7 cases of total thyroidectomy, and 21 cases of radical thyroidectomy for thyroid cancer. There were 38 cases of thyroid adenoma resection in the non-exposed RLN group, 76 cases of thyroid most resection, 4 cases of total thyroidectomy, and 13 cases of radical thyroidectomy for thyroid cancer. 1.2.3 Surgical methods 1.2.3.1 Surgery in the RLN group Conventional incision was dissected sequentially, ligating the middle thyroid vein and the inferior thyroid artery by operating close to the intrinsic peritoneal membrane of the thyroid gland, dissecting the tracheo-esophageal groove, revealing the laryngeal retractor nerve at the lax tissues under the lower edge of the cricoid cartilage and exposing it throughout the whole process, ligating the inferior thyroid artery and protecting the laryngeal retractor nerve to perform thyroid adenoma excision and most of the thyroid resections, total thyroidectomy, radical thyroidectomy for thyroid cancer. 1.2.3.2 Surgery in the non-exposed RLN group Surgery in the non-exposed RLN group is performed by preserving the capsule wall at the back of the gland as much as possible, i.e., the “intracapsular resection of the thyroid gland” method, which is used to perform adenomectomy of the thyroid gland, major resection of the thyroid gland,9 total resection of the thyroid gland, and radical resection of thyroid cancer. In the case of total resection, the remaining glandular tissue on the upper part of the capsule wall can be removed by scraping with a sharp-edged spatula. 1.3 Judgment and observation criteria of intraoperative and postoperative injury RLN injury was judged by the criteria of intraoperative and postoperative hoarseness, loss of voice, respiratory difficulty and choking in severe cases, and paralysis of the vocal cords seen by fiberoptic laryngoscopy. 1.4 Statistical methods All data were processed with SPSSl2.0 statistical software, count data were tested by x2 test, measurement data were tested by t test, and the test was statistically significant at P<0.05. 2.Results There was 1 case of temporary injury of RLN in the revealed RLN group, with an injury rate of 0.63% (1/158) and no permanent injury. The rate of temporary RLN injury in the non-exposed RLN group was 6.87% (9/131), and the rate of permanent RLN injury was 0.76% (1/131), with statistically significant differences (P<0.05). 3, Discussion 3.1 Exploration of the problem of recurrent laryngeal nerve exposure (RLN) According to the literature, the incidence of recurrent laryngeal nerve injury in thyroid surgery is reported to be 0.3%-10.7%, usually around 2%, and in the case of secondary surgery, up to 14.3% [4-6]. Regarding the exposure of the recurrent laryngeal nerve, the author believes that the exposure of the recurrent laryngeal nerve during thyroid surgery cannot be generalized, and that simple thyroid nodules and initial thyroid surgery can effectively protect the recurrent laryngeal nerve by preserving the capsule wall at the back of the gland, i.e., the method of “intracapsular resection of the thyroid”, and according to statistics from the literature, the incidence of bilateral recurrent laryngeal nerve paralysis was only 0.2% in the case of intracapsular gland total resection. According to literature statistics, the incidence of bilateral laryngeal nerve palsy is only 0.2% in total resection of the intracapsular gland (about 2% in extracapsular resection); due to the large tumor, anatomical variations of some nerves, postoperative hematoma compression after the second or second operation, and positional changes caused by scar adhesion and traction, it is unreliable to protect the laryngeal nerves from injury simply by the method of “intracapsular resection of the thyroid gland”, but it is effective to reduce unnecessary injuries by exposing the laryngeal nerves. In this study, the injury rate of the exposed RLN group was 0.63% (1/158), which was significantly lower than that of the non-exposed RLN group, which was 7.63% (10/131); among these cases, two cases of excessive intraoperative traction injuries due to large tumors were caused by the “intracapsular thyroidectomy” method of laryngeal protection, and two cases were caused by the operator’s inability to operate delicately and to stop bleeding thoroughly, which led to the injury of the laryngeal nerve. Two cases of compression damage to the recurrent laryngeal nerve due to incomplete hemostasis caused by poor operation, five cases of secondary surgical damage, and one case of anatomical variation damage; many scholars believe that exposing the recurrent laryngeal nerve during thyroid surgery is the gold standard for avoiding damage to the recurrent laryngeal nerve [7]. However, exposure of the recurrent laryngeal nerve may be damaged in the process, the author of one case due to overemphasis on the exposure of the nerve led to a large ligature injury in the process of hemostasis of the wire knot dislodgment, and timely detection to avoid permanent damage to the nerve. The author’s experience is that benign thyroid nodules are small, the initial surgery, according to the anatomical location of the regional protection of the recurrent laryngeal nerve is not deliberately dissected to avoid nerve injury; larger tumors, larger surgical scope, re-operation, especially under general anesthesia should be routinely dissected the recurrent laryngeal nerve, which can effectively avoid recurrent laryngeal nerve injury. 3.2 Precautions for avoiding the injury of recurrent laryngeal nerve (RLN) The injury of recurrent laryngeal nerve is one of the important complications of thyroid surgery, and the recurrent laryngeal nerve area is most likely to be injured during the surgery, so to avoid the injury of recurrent laryngeal nerve, the author believes that there are the following points: 1. Skillful mastery of the thyroid nerve, blood vessels and other adjacent local anatomy, especially the recurrent laryngeal nerve, the laryngeal superior laryngeal nerve anatomy, blood supply, alignment, function, etc. 2. Under the premise of ensuring standardization, the integrity of the back of the gland should be preserved, and the inferior thyroid artery should be ligated close to the common carotid artery and far away from the back of the gland.3 Intraoperative operation should be performed carefully to avoid frustration pinching and excessive pulling, and hemostasis should be performed accurately to avoid large ligatures, and hemostatic suture should not be too deep in the tracheo-esophageal sulcus.4 Intraoperative application of the electrocautery knife next to the nerves should be performed with reduced power to avoid cauterization of the nerves, destruction of the nutritive blood vessels leading to nerve injuries.5 General anesthesia, reoperation In thyroid surgery with large tumors, it is recommended to routinely expose the recurrent laryngeal nerve, but try to avoid pursuing “skeletonization” of the nerve. Familiar with the anatomical characteristics of the recurrent laryngeal nerve in thyroid surgery, standardized fine operation, intraoperative exposure of the recurrent laryngeal nerve, especially in general anesthesia, reoperation, and thyroid surgery with large tumors, can effectively avoid and prevent the occurrence of recurrent laryngeal nerve injury complications, which is worthy of clinical promotion and application.