The incidence and detection rate of thyroid nodules has increased dramatically, making them a common clinical condition. The widespread use of modern imaging techniques, mainly high-frequency ultrasound, has led to the detection of a large number of physiological thyroid nodules (e.g., glial retention cysts), benign nodules (e.g., adenomas, adenomas, inflammation), and malignant nodules (even subclinical microscopic thyroid cancers several millimeters in size). The increase in incidence and detection rate is inevitably accompanied by an increase in demand for treatment, especially the treatment concept of protecting thyroid function and eliminating surgical scars has won the hearts of patients, and diversified and minimally invasive treatments for thyroid nodules have become the direction of development. Ultrasound image guidance and thermal ablation coagulation treatment technology are the important technical guarantee to realize diversified and minimally invasive treatment.
After 11 years of exploration and research in China, ultrasound-guided percutaneous thermal ablation treatment of thyroid nodules has entered the primary stage of gradual maturity and prosperity, and tens of thousands of thyroid nodule patients have benefited from the multiple and minimally invasive effects of thermal ablation treatment. Although the number of surgically resected cases still dominates the composition ratio, due to the diversity and complexity of thyroid nodules in terms of number, size, nature and age of onset, it is increasingly difficult to meet the needs of patients with a single method of surgical resection, and ultrasound-guided thermal ablation therapy will definitely become the preferred choice for the majority of thyroid nodule patients. Scientific research, standardized practice and orderly promotion are the attitudes that must be held to promote the healthy development of thermal ablation technology.
I. Indications and contraindications of thermal ablation treatment for thyroid nodules
(A) Indications
1. Benign thyroid nodules: adenoma, nodular adenoma, glial retention cyst over 2 cm, mass-like Hashimoto’s inflammation.
The treatment of benign nodules follows the basic principles of surgery, emphasizing “symptomatic, bulging (affecting aesthetics) and functional” nodules as the three benchmarks of treatment. The four special values of special physical group, special age group, special development group and special treatment history group are highlighted.
2. Hyperthyroidism: Surgical resection is an important treatment for hyperthyroidism, and thermal ablation can be used as an alternative to surgical treatment for hyperthyroidism. However, the treatment order of “internal medicine first, then surgery” should be upheld for hyperthyroidism, and after the disease enters the surgical treatment stage, the treatment mode of “ablation first, resection light” should be explored. We should resist the risky behavior of “thermal ablation regardless of disease and stage”.
3.Malignant nodules of thyroid: mainly for differentiated carcinoma with clear diagnosis.
(1) Microscopic carcinoma (TMC) less than 1cm in diameter, single or multiple can be recommended for intensity A.
(2) Diameter greater than 1 cm or even adherent to the envelope but without infiltration with surrounding structures Recommended intensity grade A.
(3) with no more than three regional lymph node metastases ipsilateral to the patient.
(4) Not recommended for those with multiple regional lymph node metastases in the neck bilaterally.
4. Differentiated carcinoma with lymph node metastasis in the neck
If lymph node metastasis reappears after total thyroidectomy, cervical lymph node dissection or iodine nail cleansing treatment, thermal ablation therapy is suitable unless ultrasound images show unclear lesions.
(II) Contraindications
1.Severe adhesions between nodes and esophagus, trachea and nerves, which cannot be separated.
2.Severe coagulation dysfunction, or those who have not reached the standard time of discontinuation of long-term blood-activating drugs.
3.Severe calcified nodules, where puncture access to the needle is expected to be extremely difficult
4, those with abnormal nodule location, resulting in an extremely dangerous puncture access path
5.Severe cough, asthma, and eruption.
Comparison of various means and advantages of thermal ablation treatment of thyroid nodules
1.Microwave ablation has fast warming speed, large warming range, wide range of application, strong hemostatic effect, and risk of needle breakage.
2.Radiofrequency ablation is slower than microwave in terms of heating speed and amplitude, and the ablation range is smaller than microwave, without the risk of needle breakage but with the risk of electrocution.
3.Laser ablation has fast warming speed and can cause vaporization, with limited ablation range, weak hemostatic effect and risk of fiber carbonization and fracture.
Clinical advantages and problems of thermal ablation treatment of thyroid nodules
(A) Clinical advantages are mainly reflected in precision, minimally invasive, exact efficacy, protection of function, low recurrence rate and repeatability
1. It is a treatment that responds to the needs of patients.
2.It is a scientific treatment means supported by scientific and technological basis.
3. is a treatment means with safety guarantee.
4. It is a minimally invasive or even ultra-minimally invasive treatment in the true sense.
(2) The main problem lies in the lack of standardization in the process of development and promotion. Clinical basic scientific research is still weak.
1.The absorption rate of ablation area varies greatly among individuals, and the problem of promoting absorption has to be solved.
2, the name of the procedure is not uniform, some titles lack scientificity, and even have obvious misleading, such as “superconducting”, “four-dimensional” and other terms.
3, the technical level of practitioners vary greatly, and the qualification is not enough to prove.
4.The standard of treatment places is not uniform, or even too simple.
5. Insufficient attention to the management of ablation anesthesia and lack of professional anesthesia management measures.
Safety hazards and preventive measures of thermal ablation of thyroid nodules
(A) Safety risks
1. Thermal damage to the surrounding structures of the thyroid gland mainly involves the nerves, trachea, esophagus and parathyroid glands.
2. needle-stick injuries to peri-thyroidal structures mainly involving blood vessels, esophagus and trachea.
3, bleeding intraoperative bleeding, delayed postoperative bleeding.
4, inappropriate and incomplete ablation.
5, the lesion is missed and not fully treated.
(II) Prevention countermeasures
1, liquid isolation method is extremely important measures to prevent thermal injury and prevent needlestick injury. One isolation, dynamic isolation, hedge isolation.
2, needle bar paddling method is an important supplementary technique to the liquid isolation method.
3, needle bar dragging method is an important supplementary technique of liquid isolation method.
4, the method of needle feeding with heat is an excellent technique to improve the smoothness of needle feeding and to avoid accidental damage by violent needle feeding.
5, the coarse needle biopsy method after blocking blood flow is an effective method to reduce bleeding from puncture biopsy of nodes with rich blood supply.
6, ablation after interruption of blood flow is an effective method to reduce bleeding in ablation of blood-rich, colloid-rich, soft follicular nodules.
7. thermal ablation of bleeding sites is the most effective method for rapidly stopping bleeding during surgery
8, the effective use of CDFI/CEUS blood flow observation mode can detect the ablation inappropriate area in time and guide the complete ablation.
9. High-definition ultrasound imager and multi-nodule numbering management.
V. Core features and advantages of thermal ablation of thyroid nodules followed by puncture biopsy
1. A large sample study confirms that puncture sampling immediately after thermal ablation does not affect the correctness of pathology reading is the core feature that allows the implementation of puncture biopsy after thermal ablation.
2. Advantages of post-thermal ablation puncture biopsy: it can effectively reduce puncture bleeding; it can improve the quality of specimen formation of lax and colloid-rich follicular nodules, which is beneficial to pathological diagnosis.
Neck nerve protection associated with thermal ablation of thyroid nodules
Depending on the location of the nodule, the protection of the vagus nerve, the recurrent laryngeal nerve, the superior laryngeal nerve, the sympathetic nerve (especially the sympathetic ganglion), the brachial plexus nerve, the parasympathetic nerve, the greater auricular nerve and the hypoglossal nerve should be given high priority. The fluid isolation method is the primary protection measure.
VII. Path selection for thermal ablation of thyroid nodules
1.The path of puncture needle should follow the selection principle of the most convenient, safest and shortest distance.
2, the content of the ultrasound imaging section of the puncture needle should contain thyroid nodules, trachea, esophagus, and blood vessels (at least the common carotid artery).
3. advocating transverse or oblique transverse section-guided needle insertion, and striving to avoid longitudinal thyroid-guided needle insertion.
4, the two main needle path orientation from the inward to the outward needle and from the outward to the inward needle. The choice of the specific orientation depends on the location and size of the nodule. In general, the inside-out approach is preferred, which can reduce the damage to the sternocleidomastoid muscle and swallowing muscles and avoid direct damage to the trachea and esophagus.
Eight, thyroid nodule thermal ablation treatment patient position and operator orientation selection
1.Patients should be placed in supine position, with or without soft pads of about 5cm in height under the back of the shoulders. The neck is lightly hyperextended. Remove undergarments (bra) if possible.
2. The operator can sit on the patient’s head side or on the left and right sides. When sitting on the patient’s head side, the ultrasound probe orientation needs to be noted as different from sitting on both sides to avoid confusion between the left and right image orientation.
Nine, thyroid nodule thermal ablation sterilization management
1. It should be performed in a regular operating room or interventional room equipped with sterilization facilities.
2. Patients should wear surgical caps to cover their hair.
3, the neck sterilization area is large enough and should not be too limited to the anterior neck area.
4. The sterile towel sheet should cover a large enough area and should not be too limited to the anterior neck area. The patient’s mouth, nose, eyes and chest should be covered. Because the head frame is not used, thick and heavy thyroid surgical towels should be avoided as much as possible, and a combination of lightweight cavity towels and square towels should be used as much as possible, and a special surgical kit for thyroid ablation of March Spring is recommended.
X. Management of anesthesia for thermal ablation of thyroid nodules
1.Patients wear oxygen mask or nasal oxygen tube for continuous oxygen supply.
2.Promote local anesthesia in the ablation area of the neck, pay attention to control the total amount of lidocaine; no cervical plexus anesthesia or intravenous anesthesia is needed, and sedation and other measures should be used depending on the specific situation.
3.A professional anesthesiologist should assist in on-site management, control the unstable state of blood pressure, heart rate and respiration, and deal with emergencies.
Number management of thyroid nodule thermal ablation
1.There should be a special ablation team or ablation treatment group. Patients must be carefully examined by the main operators before surgery to determine the number, location, size, nature of ultrasound images, degree of blood supply and pathological nature of the nodules to be treated.
2. presetting the puncture path for each nodule so that there is a preoperative count and no intraoperative confusion.
3. Adopt nodule numbering management for multiple nodules, and mark the approximate orientation and size of each nodule on the thyroid anatomy schematic. The ablation assistant will remind the operator of the ablated nodules and the nodules to be ablated in time.
Immediate intraoperative assessment of the effect of thermal ablation of thyroid nodules
Ultrasonography is relied upon to dynamically assess the completeness and adequacy of the ablation.
1.Immediate pre-ablation ultrasonography.
2.Immediate ultrasonography during ablation.
3.Immediate post-ablation ultrasonography.
Staged ablation of large nodules
It is important to communicate with patients in advance to reduce misunderstanding and disputes.
1.Nodules over 4 cm.
2.Nodules that protrude into the posterior sternum.
3.Multiple nodules causing severe enlargement of the thyroid gland.
4. Hyperthyroidism.
XIV. Follow-up of patients after ablation
(I) Follow-up contents
1.Ultrasound examination of thyroid gland and neck.
2.Thyroid function index and related antibodies.
3. Clinical symptom rating scale of the patient.
(B) Efficacy assessment
1.Nodule biopsy residual rate.
2.The completeness of necrosis in the ablation area.
3.The rate of volume reduction in the ablation area.
4.The degree of preservation or recovery of normal glandular tissues.
5. fluctuations in thyroid function indicators and the need for clinical management.
6.Incidence of neoplastic nodules or lymph node metastasis.
XV. Disposition of recurrence after ablation of differentiated carcinoma
1.Recurrence of cancer identified by ultrasound imaging + puncture biopsy.
2.Treatment of recurrent cancer by local ablation again.
3.The reasonable use of eugenol.