| 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. |
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