【作者】 雷尚通；

【导师】 丁自海；

【作者基本信息】 南方医科大学 ， 组织胚胎与解剖学， 2014， 博士

【摘要】 近年来甲状腺癌(Thyroid cancer)的发病率不断上升,已经成为外科最常见的恶性肿瘤之一,严重威胁着人类的生命和健康。甲状腺癌的主要治疗方式有外科手术、放射性碘(Radiotive iodine, RAI)治疗、促甲状腺素(Thyroid stimulating hormone,TSH)抑制治疗。外科手术是最重要的治疗手段,也是综合治疗的基础。积极正确的手术治疗可提高患者的长期生存率,降低局部复发率。甲状腺癌尤其是分化型甲状腺癌(Differentiated thyroid cancer, DTC)容易发生淋巴结转移,而且往往最先转移至中央区淋巴结。因此,甲状腺癌手术治疗的目标是切除肿瘤原发灶、受累的肿瘤周围组织以及转移的颈部淋巴结。手术完全切除对预后有重要影响。残余腺体内的病灶及淋巴结转移灶是肿瘤持续存在或复发的最常见原因。同时,完整切除有利于对肿瘤进行精确分期,指导下一步治疗、预后评估以及确定随访方案。手术的另外一个重要目标是最大限度地降低手术相关的并发症的发生率。手术范围越大,复发率越低,预后越好,但并发症也越多,患者术后生存质量(Quality of live, QOL)也越低。因此,适宜的手术方式不仅可以降低甲状腺癌患者的复发率,对患者的生存质量亦有深刻影响。虽然甲状腺癌的发病率不断上升,但主要以直径小于2cm的肿瘤为主,而且,甲状腺癌的死亡率并未明显增加。因此,甲状腺癌的手术也逐渐由创伤较大颈淋巴清扫到保留功能的改良颈淋巴清扫再到选择性颈淋巴清扫,清扫范围逐渐缩小。美国甲状腺学会(American Thyroid Association, ATA)2009年诊治指南及英国甲状腺学会(British Thyroid Association, BTA)的指南将甲状腺癌的颈淋巴结分为中央区和外侧区。两个指南都强调央中区淋巴清扫的重要性,认为中央区是分化型甲状腺癌最常发生转移的部位,中央区淋巴结清扫术对提高分化型甲状腺癌疗效意义深远,应予以重视和掌握。目前国内对乳头状癌病人主张初始手术常规清扫中央区淋巴结者占主流,认为初始手术清扫中央区淋巴结既可明确颈部淋巴结转移与否的诊断,又可阻断日后淋巴结可能发生转移的途径,对显著降低局部复发的危险、减少肿瘤相关死亡率和提高存活率有显著意义。然而目前尚缺乏中央区淋巴清扫术的规范操作和质量控制标准,迫切需要一种安全、有效、便于学习的操作技术。同时,不规范的手术必然导致局部复发率、再次手术率升高。由于瘢痕粘连或解剖结构不清,再次手术难度大,风险高,并发症多,因此有必要寻求新的手术入路或手术方式来减少甚至避免瘢痕的影响。当然,任何新的手术方式或手术入路都是建立在对目标操作部位或器官临床应用解剖特点的新的认识基础上。因此,系统阐述与甲状腺癌中央区淋巴清扫术及入路相关的筋膜及筋膜间隙的特点,重新确定甲状腺癌中央区淋巴清扫术的各个操作平面并界定切除范围,找到相应的解剖学标志,是改善甲状腺癌手术操作、减少手术并发症的有效手段。基于上述原因,我们通过对尸体以及甲状腺癌患者术中的解剖学观察,从解剖学角度分析了甲状腺癌中央区淋巴清扫的手术范围、术中外科平面的确定和具体手术操作方法。在此基础上我们提出了甲状腺系膜(Mesothyroid)的概念,并详细描述甲状腺系膜的解剖学特征；‘同时提出了甲状腺系膜切除术(Total mesothyroid excision)的概念,用于治疗甲状腺癌,并介绍了该手术的操作方法和优势；另外本研究还提出了肌间隙入路法的甲状腺癌再次手术方法,为甲状腺癌中央区淋巴清扫及甲状腺癌再次手术提供有实用价值的解剖学依据。同时将新的手术方式或手术入路应用到临床,证实是可行、安全和有效的,为新技术的推广提供了依据。第一部分：甲状腺周围筋膜及筋膜间隙的解剖学观察1研究目的：通过尸体解剖和临床手术观察,从临床应用解剖角度重新认识甲状腺周围筋膜及筋膜间隙的解剖特点,结合甲状腺癌转移途径和甲状腺癌中央区清扫范围对甲状腺周围相关的筋膜和筋膜间隙进行系统阐述,试图为甲状腺癌中央区清扫术的手术范围、入路层面及甲状腺癌再次手术入路等提供可以借鉴的解剖依据。2材料和方法：10%福尔马林固定的标本5具共10侧,用于观察甲状腺周围筋膜及筋膜间隙。10例甲状腺癌患者,用于术中确认甲状腺周围筋膜及筋膜间隙。纳米碳混悬液1ml/支,5支,常规解剖器械一套。在福尔马林固定标本上模拟甲状腺切除和中央区淋巴清扫术,观察相关筋膜及筋膜间隙的分布特点,边解剖、边观察、边拍照。同时,运用尸体解剖中得到的筋膜和筋膜间隙的相关知识,对甲状腺癌患者行甲状腺切除+中央区淋巴结清扫,验证相关筋膜和筋膜间隙的在手术中的意义。3结果3.1肌间隙及咽后间隙：胸骨舌骨肌与胸骨甲状肌之间存在一无血管的肌间隙,向外侧延伸至颈血管鞘。再沿颈血管鞘内侧切开内脏筋膜可进入气管旁脂肪组织与椎前筋膜之间的咽后间隙。3.2气管前筋膜：甲状腺前方有一层完整筋膜覆盖,向上延伸至舌骨,向下延伸至纵膈,并覆盖喉前及气管前脂肪淋巴组织。气管前筋膜分为两层,两层筋膜中间有脂肪组织、淋巴结、淋巴管、甲状腺下静脉、甲状腺最下动脉、胸腺等,呈“三明治”样结构。3.3舌骨下肌后间隙：气管前筋膜与舌骨下肌筋膜之间存在一潜在可分离的舌骨下肌后间隙。3.4气管前间隙：气管前筋膜后层与气管之间有一潜在无血管的间隙,此间隙向下通上纵膈,向上与气管与甲状腺之间的间隙及喉与喉前筋膜之间的间隙相通,并向两侧延伸至气管食管沟。3.5甲状腺系膜：气管旁脂肪组织与气管前脂肪组织相延续,结构相似,有前后两层筋膜覆盖,甲状腺血管、淋巴系统走行其中,也呈“三明治”样结构；前后筋膜在外侧与血管鞘向融合,内侧与甲状腺相连,其结构类似肠系膜,我们认为这就是甲状腺系膜。4结论4.1甲状腺存在系膜。甲状腺系膜位于甲状腺后方及下方,呈“U”形分布于气管前和气管旁,内侧界为甲状腺,外侧界为颈血管鞘,下界为无名动脉。4.2甲状腺癌中央区淋巴清扫术即为甲状腺系膜切除术。中央区淋巴结均位于甲状腺系膜内,切除甲状腺系膜可达到整块切除(en bloc)中央区淋巴的目的。4.3咽后间隙是甲状腺系膜切除术的正确外科平面。咽后间隙是甲状腺系膜与椎前筋膜之间的无血管间隙,是外科手术的理想平面。4.4颈血管鞘内侧缘是进入外科平面的标志线。甲状腺系膜在外侧与颈血管鞘相融合,两者的交界线及为颈血管鞘内侧,是进入咽后间隙的标志线。4.5胸骨甲状肌和胸骨舌骨肌之间的间隙以及咽后间隙可作为再次手术入路。甲状腺癌再次手术时,由于胸骨甲状肌与甲状腺床粘连紧密,在经此操作难度大风险高。而胸骨舌骨肌和胸骨甲状肌之间的间隙以及咽后间隙未曾涉足,经此入路可有效避开瘢痕的影响,因此可作为再次手术入路。第二部分：甲状腺系膜切除术甲状腺癌易发生淋巴转移,因此甲状腺切除+中央区淋巴结清扫术是甲状腺癌的主要手术方式,但至今尚无一种标准的操作方法。我们通过对颈筋膜的解剖学研究和临床手术观察后发现,同消化道的其他部位一样,甲状腺周围也存在系膜样结构,甲状腺的血管、淋巴系统均位于系膜内,且系膜与周围筋膜或脏器之间存在疏松的无血管的筋膜间隙。循筋膜间隙进行手术,将系膜样结构的中央区组织完整切除的方法可行、安全、有效、便于学习,且能达到整块切除的目的,是一种值得推荐的手术技术,我们称之为甲状腺系膜切除术第三部分：甲状腺系膜切除术治疗甲状腺癌的临床应用1研究目的：探讨甲状腺系膜切除术治疗甲状腺癌的安全性、可行性及临床价值。2材料和方法：总结2012年1月至2013年12月间南方医院普外科施行的226例甲状腺癌手术患者的临床资料,比较接受甲状腺系膜切除术的患者和单纯甲状腺切除术患者的手术学、并发症等资料。3研究结果：166例患者成功实施甲状腺系膜切除术,63例行甲状腺系膜切除术+颈侧区淋巴清扫术,41例行单纯甲状腺全切术,19例行次全切除等其他手术。甲状腺系膜切除术手术时间为130(115-150)min,长于单纯甲状腺切除组106(85-120)min,差异具有显著性意义(P<0.001)；两组术中出血量、术后住院时间分别为30(20-50)ml和20(20-50)m1、(3.7+1.5)d和(3.4±1.1)d,无明显差异(P=0.233、P=0.192)。甲状腺系膜切除组术后暂时性低钙血症发生率为13.1%,明显高于甲状腺切除组0%,差异具有显著性(P=0.020)；两组声音嘶哑和术后出血的发生率分别为4.0%和2.4%、1.0%和2.5%,无明显差异(P=1.000,P=0.241)；术后平均随访13个月,两组均无一例死亡,无一例复发,术后1-3个月甲状旁腺素均恢复正常,无永久性甲状旁腺功能低下,甲状腺系膜切除组中2例行喉返神经切除吻合术者始终有声音嘶哑。4结论：甲状腺系膜切除术安全、可行,且符合肿瘤学原则,可作为分化型甲状腺癌的一种治疗方法。第四部分：肌间隙及咽后间隙入路法甲状腺中央区切除术分化型甲状腺癌(Differentiated thyroid cancer DTC)生长缓慢,预后良好,但长期随访仍有较高的复发率,且复发多位于中央区。分化型甲状腺癌复发后经再次手术仍可获得良好预后。由于瘢痕粘连、解剖结构异常、层面消失等原因,再手术操作困难,时间长,并发症多。合理的手术操作技术有助于降低手术难度,缩短手术时间,减少手术并发症,降低再次复发率。我们通过解剖学研究发现,胸骨舌骨肌与胸骨甲状肌之间存在一无血管的肌间隙,向外侧延伸至颈血管鞘。再沿颈血管鞘内侧分离即可进入甲状腺及其脂肪淋巴组织与椎前筋膜之间的咽后间隙。因此我们尝试通过肌间及咽后间隙入路法,应用层面优先技术,以椎前间隙作为操作空间,从背侧进行手术,反其道而行之,证实是可行的,是一种值得推荐的手术操作方法。第五部分：肌间隙及咽后间隙入路法中央区切除术在甲状腺癌再次手术中的应用1研究目的：介绍肌间隙及咽后间隙入路法的中央区切除术,探讨该技术在甲状腺癌再手术中的安全性、可行性及临床价值。2材料和方法：回顾性分析2012年1月至2013年12月间南方医院普外科施行的42例甲状腺癌再手术患者的临床资料,并比较甲状腺癌再次手术和初次手术患者的手术学、并发症等资料。3研究结果：所有患者均采用肌间隙及咽后间隙入路法完成手术；6例行残余甲状腺切除术,19例行残余甲状腺切除+中央区淋巴清扫术,16例行残余甲状腺切除+中央区清扫+颈侧区清扫术,1例行姑息性切除术；再次手术者原因为初次手术范围不足者8例(19%),甲状腺癌局部复发者13例(31%),局部复发并颈部淋巴转移5例(11.9%),颈侧方淋巴结转移者16例(38.1%)。再次手术与初次手术的时间分别为190(120-265)min和146(120-195)min,差异无显著性意义(P=0.128)；再次手术组与初次手术组术中出血量分别为50(30-100)ml和50(20-80)ml,差异无显著性(P=0.148)；再次手术组术后短期并发症发生率为9.8%,与初次手术组(8.2%)相比无显著性差异(p=0.760),两组暂时性低钙血症的发生率分别为12.2%和6.2%,声音嘶哑的发生率分别为5.1%和4.9%,差异均无显著性意义(p=0.186、p=1.000)。两组术后第一天和1个月甲状旁腺素分别为(15.44-7.2)、(16.8±10.1)和(26.44±6.2)、(29+8.4),差异无显著性意义(P=0.409、P=0.074)。再次手术组术后住院天数为(5.8±3.4)d,长于初次手术组(4.2±2.2)d,差异具有显著性意义(P<0.001)。4结论：甲状腺癌再手术时采用层面优先技术,以肌间隙为入路,以咽后间隙作为操作平面,从背侧进行手术,方法可行,不增加手术时间和手术风险,仅延长术后住院时间,因此,层面优先技术是一种安全、可行的、值得推荐的手术操作技术。更多还原

【Abstract】 In the recent years, the incidence of thyroid cancer has kept rising and has become one of the most common malignant surgery tumor threatening human life. The main therapies for thyroid cancer include surgical operation, I131treatment, TSH inhibitory treatment. Surgery is the-most important treatment, and the basis of comprehensive treatment. The correct as well as positive operation could raise the long-term survival rate of patients and reduce the local recurrence rate.Lymph node metastasis is prone to happening in the thyroid cancer, especially its well-differentiated type, and usually first spreads to central neck compartment, therefore the target of the surgery is to remove the primary tumors, the involved surrounding tissues, and the metastatic central cervical compartment lymph nodes. The complete removal in the surgery has a vital impact on the prognosis, the lesion in the remaining gland as well as the metastatic lymph node is the most common fashion for recurrence. The en bloc could help ensure accurate tumor staging, thus instruct the following treatment, the assessment of prognosis and the follow up. Another important aim of the surgery is to reduce the complication accompanying surgery to the most. The broader the surgical region, the lower the recurrence rate and the better the prognosis would be, but the more complication there could be, meanwhile the life quality of the patients might decrease. Therefore, the appropriate means of surgery could not only lower the recurrence rate of thyroid cancer, bu also has a deep impact on the life quality of patients.Though the incidence of thyroid cancer has kept rising, but mainly refers to tumors less than2cm. In addition, the death rate of thyroid cancer didn’t have an remarkable increase. Therefore the surgery for the thyroid cancer has gradually developed from extended radical neck dissection to modified radical neck dissection and to the selective neck dissection, reducing dissection area.The2009edition guidelines of American Thyroid Association (ATA) and the guidelines of British Thyroid Association(BTA) divided the cervical lymph nodes to the central and lateral compartments. Both guidelines emphasized on the importance of central area lymph node dissection, and considering the central compartment as the area where the metastasis of differentiate thyroid cancer most often happens, and the central compartment lymph node dissection means a lot in improving the therapeutic effect of differentiated thyroid cancer, which should be emphasized and managed well. Presently in our country, the mainstream opinion falls in taking the routine central compartment lymph node dissection on treating papillary carcinoma. It is thought that the central compartment lymph node dissection in the primary operation could not only decide whether the lymph node has spread,-but also block the possible ways through which the lymph nodes might spread, therefore is important in reducing the local recurrence and the death concerning cancer, as well as raising the survival rate.However presently there lacks the standard for the operation and quality control of the central compartment lymph node dissection, and is in great need of safe, effective and easy-to-learn operation method. Meanwhile, the nonstandard surgery will lead to the increase of local recurrence and reoperation. The reoperation is more difficult and risky and is accompanied with many complications because of scar adhesion or anatomical vagueness. Therefore, it is necessary to find a new surgical approach or method to reduce or to remove the influence of the scars.Of course, any new surgical method or approach is based on the new anatomical recognition of the target region. Therefore it is important to systemically explain the fascia and fascial space related to the surgical approach of the central compartment lymph node dissection, and redefine the operation and removing region of central compartment lymph node dissection as well as finding the related anatomical landmarks, in order to improve the surgical operation of the thyroid cancer and reduce the accompanying complications. Based on the above reasons, we did anatomical observations on the corpse and patients to analyze the surgical regions of the central compartment lymph node dissection of the thyroid cancer, and define the surgical planes as well as explore detailed operation methods, attempting to provide practical anatomical basis for central area lymph node dissection and reoperation of thyroid cancer.meanwhile applying the new surgical technigue or approach into clinical trials, observing its feasibility, safety and effectiveness, providing basis for the application of the new technology.Part1:Anatomic Observation of Fascia and fascial space surrounding the thyroid gland Objective:Through anatomy of the specimen and clinical observation of operations, redefine the anatomical features of fascia and fascial space around the thyroid gland, combining the metastasis path and the region of central compartment lymph node dissection, finally explain the two parts and provide anatomical basis for the region of central compartment lymph node dissection, the surgical planes and the reoperation approach.Methods and materials:5specimen with10sides were fixed in10%formalin and used to study the fascia, fascial space around the thyroid gland.10patients with thyroid cancer are used to define the fascia and fascial space during the operation.5Carbon nanoparticles (1mL each),1set of normal dissecting instrument were prepared.Model the the thyroid excision and the central compartment lymph node dissection on the specimen fixed in10%formalin, and observe the features of the fascia and fascial space. The dissection, observation and photo-taking goes on together. Meanwhile, apply the knowledge of the fascia and fascial space obtained from the operation, do the thyroid excision and the central area lymph node dissection on the patients with thyroid cancer, and prove the meanings of the two parts during surgery.Results:There is a vessel free intermuscular space between the sternohyoid muscle and the sternothyroid muscle, going from the lateral part to the carotid sheath. Then separate along the inside of carotid sheath, enter the retropharyngeal space between the thyroid gland, its fat lymphoid tissue and the prevertebral fascia. There is a complete fascia on the front of the thyroid gland, and spreading upwards to the hyoid bone, downward to the mediastinum, covering the fat lymphoid tissue before the throat and the trachea. There is a hidden and separatable intermuscular space between it and the infrahyoid muscles, pretracheal layer is divided into two layers, the interspace of which has fat tissues, lymph nodes, lymphatic vessels, inferior thyroid vein, arteria thyroidea ima and the thymus, which looks like Sandwich. There is a vessel-free space between the pretracheal fascia and the trachea, which goes down to the mediastinum and upward to the space between trachea and the thyroid, the space between throat and prethroat, and goes to bilaterally to the tracheoesophageal groove. The paratracheal fat tissue connects to the pretracheal fat tissue and has a similar construction with two fascias covering front and back, containing vessels, lymphatic system, which looks like sandwich; The front and back fascia combines with carotid sheath from the outside, and the inside of which is connected with, the thyroid and is similar to the mesentery. Cut the fascia along the inside of carotid sheath, the interthroat space between the paratracheal fat tissue and prevertebral fascia.Conclusions:The thyroid gland has mesentery which is located in pretracheal and paratracheal area.The central compartment lymph node dissection should completely remove the pretracheal and paratracheal lymph nodes, that is mesothyroid excision. There is fascial space between the organs and fascia of the thyroid gland. The space is a natural approach for the operation, and is an important landmark for the complete removal of cancer. Therefore it helps to improve the safety and effectiveness of thyroid cancer. It cannot be applied in the reoperation of thyroid cancer because there is adhesion between the sternothyroid and thyroid bed, there for the space between sternothyroid and sternohyoid as well as the interthroat space could be used as the operative approach.Part2:Total mesothyroid excisionLymphatic metastasis often happens in the thyroid cancer, therefore the excision combined with the central compartment lymph node dissection are the main treatment, but there is no standard approach up till now. We found out through the anatomical study on the cervical fascia and clinical surgery, like other parts in the digestive tract, there is mesentery around the thyroid gland, which contains the vessels and the lymphatic system. And there is fascial spaces between the fascia and surrounding organs. Operation along the fascia and complete excision of the central part is feasible, safe and effective, which is easy to learn and can reach the aim of en bloc resection. Therefore it is a new approach worth recommendation. We call it the " Total mesothyroid excision ".Part3:The clinical application of total mesothyroid excision on the treatment of thyroid cancerObjective:To discuss the safety, feasibility and clinical value of total mesothyroid excision on the treatment of thyroid cancer.Methods:Gather and analyze the clinical data of226patients with thyroid gland during January to September in year2012who underwent surgery in Nanfang hospital, and compare the operations between the patients undergone total mesothyroid excision and the conventional thyroid excision.Results:166patients successfully underwent total mesothyroid excision, among which63underwent thyroid mesorectal excision and lateral cervical compartment lymph node dissection,41underwent conventional thyroid excision,19underwent secondary excision. The operation time for the thyroid mesorectal excision is130(115-150)min, longer than the thyroid excision group which is106(85-120)min, with significant difference(P<0.001); the amount of blood loss, postoperative hospital stay in two groups are30(20-50)mL,20(20-50)mL and (3.7±1.5)d,(3.4±1.1)d, respectively, with no significant difference(P=0.233, P=0.192). The incidence of temporal hypocalcemia after the thyroid mesorectal excision was13.1%, remarkably higher than the thyroid excision group(0%), with a significant difference(P=0.020); the incidence of hoarseness and postoperative bleeding were respectively4.0%,2.4%and1.0%,2.5%, with no significant difference(P=1.000, P=0.241).; The average follow up lasts for13months after surgery, and both groups had no death, no recurrence, and the parathyrin went back to the normal level1-3months after surgery, no permanent parathyroid dysfunction, however2patients had hoarseness in the thyroid mesorectal excision after laryngeal recurrent nerve excision.Conclusions:Total mesothyroid excision is safe, feasible and goes along well with the oncological principles, therefore could be applied as one treating method for the differentiated thyroid cancer. Part4:The dissection of central compartment nodes through intermuscular and interthroat approachesThe differentiated thyroid cancer(DTC) grows slowly and has a good prognosis, ut longterm follow ups indicates relatively high recurrence rate, and the recurrence mostly locate in the central area. The differentiated thyroid cancer has a relatively good prognosis after reoperation for its recurrence. But reoperation is difficult, time-consuming and has complications because of scar adhesion and anatomical abnormality, disappearance of layers. Reasonable operation method helps to reduce the difficult, time and the complications, as well as reducing the recurrence rate. Through anatomical study we found that there is a vessel free intermuscular space between the sternohyoid muscle and the sternothyroid muscle, going from the lateral part to the cervical vagina vasorum. Then separate along the inside of cervical vagina vasorum, the interthroat space between the thyroid gland, its fat lymphoid tissue and the prevertebral fascia. Thus we try to take the intermuscular and interthroat approach, applying the layer advanced technology, using the prevertebral fascia as the operation region and do the surgery from the back which is opposite from the normal approaches, and has been proved to be feasible as an operation method worth recommendation.Part5:The application of intermuscular and interthroat approaches in the reoperation of thyroid cancer Objective:To introduce the the central compartment removing operation through the intermuscular and interthroat approach, and discuss its safety, feasibility and clinical value in the reoperation of thyroid tumor.Methods:Retrospectively analyzed the clinical characteristics of42patients undergone reoperation of thyroid tumor, and compared the surgery as well as complication of patients undergone reoperation with patients undergone operation for the first time.Results:The intermuscular and interthroat approaches were applied on all the patients;6patients underwent the thyroid gland excision,19patients underwent the excision+the central compartment lymph node dissection,16underwent the excision+the central compartment lymph node dissection+lateral cervical compartment lymph node dissection,1underwent palliative excision; among patients underwent reoperation,8(19%) lacked enough operation area in the primary operation,13(31%) had local recurrence,5(11.9%) had local recurrence and cervical lymphatic metastasis,16(38.1%) had lateral cervical lymphatic metastasis. The duration time of reoperation and primary operations were respectively190(120-265)min and146(120-195)min, not significantly different(P=0.128); the amount of bleeding in the two groups were50(30-100)mL and50(20-80)mL, respectively, not significantly different(P=0.148); the short-term local recurrence rate of the reoperation group was9.8%, which is not significantly different from the primary operation group(8.2%)(p=0.760), the incidence of the temporal hypocalcemia of the two groups were respectively12.2%and6.2%, the incidence of hoarseness were respectively5.1%and4.9%, all had no significant difference (p=0.186, p=1.000). The parathyrin at day1and one month after the operation of the both groups were respectively(15.4±7.2),(16.8±10.1), and (26.4±6.2),(29±8.4), with no significant difference(P=0.409, P=0.074). The length of hospital stay of the reoperation group were (5.8±3.4)d, longer than the primary operation group which is (4.2±2.2)d, and has a significant difference(P<0.001).Conclusions:The reoperation of the thyroid cancer uses the layer precedence technology, taking the intermuscular space as the approach, and the interthroat space as the operation platform, doing the operation from the back. The method is feasible and doesn’t increase the operation time or the risk, only prolonging the hospital stay. Thus the layer precedence technology is a safe, feasible and recommendable surgical technigue.更多还原