| Part One Assessment of Methods and Short Term Therapeutic Response to Ultrasound-guided Radiofrequency Ablation of Thyroid NodulesObjectiveThis study aims to establish a treatment proposal of thyroid nodules by using ultrasound-guided radiofrequency ablation and investigate its techniques, means and steps, feasibility and short term therapeutic response to radiofrequency ablation of thyroid nodules.Materials and MethodsPatientsA total of153benign thyroid nodules in111euthyroid patients were treated with US-guided RFA between October2010and December2012. This study population consisted of78females and33males, aged15-66(mean age,41.80±11.13years).58patients had one nodule, and26patients had more than two nodules. The mean diameter of the nodules was (2.40±1.21) cm (ranged from0.60to7.10cm). The patients had refused surgery and requested non-surgical treatment. A written informed consent document was obtained from all patients before the procedure.On the basis of subjective descriptions of echography from US physician, masses were divided into the following three subgroups:(1) Predominantly solid, with solid components more than and equal to80%;(2) Predominantly cystic, with cystic components more than and equal to80%;(3) mixed type, other than predominantly solid or cystic. According to this criteria, there were93predominantly solid nodules,16predominantly cystic nodules and44mixed type nodules.The inclusion criteria of this study were as follows:(1)the presence of subjective symptoms (foreign body sensation, neck discomfort or pain, compressive symptom) or cosmetic problems;(2) a poor surgical candidate or refusal to undergo surgery;(3) fine-needle aspiration cytology and US findings that were compatible with a benign nodule;(4) anxiety about a malignancy.The exclusion criteria were as follows:(1) a nodule less than5mm in size;(2) a nodule with the sonographic criteria for a malignancy (taller than wide, marked hypoechoic, microcalcifications, ill-defined margins), although FNAC was a benign result;(3) previous radiation or operation history to the head and neck.Pre-ablation assessmentThe US examination, laboratory data, and FNAC were performed with all patients. Two radiologists carried out the US examination and FNAC. On Color ultrasonography, all nodules with well-defined margin were regular shape and homogeneous echognicity. Involvement with enlargement of the cervical lymph nodes and vascularity within and surrounding the masses was absent and all patients were euthyroid. Blood coagulation were all with in the normal reference limits. FNAB shows all thyroid nodules were benign.All patients took a supine position, with cervical hyperextension, local anesthesia with2%lidocaine at the puncture site,1～2mm skin incision was made. An electrode was inserted into the thyroid nodule under ultrasound guidance along the long axis of the index nodule. Then began the ablation procedure with5W of the power. The tip of the electrode was repeatedly moved from one ablated unit to another unablated unit. If the nodule located less than5mm from the vital adjacent structures of the neck, so ablation was performed with a normal saline or2%lidocaine injection at the tissue layer between the index nodule and adjacent tissues using an18-guage syringe. In the case of ablating the periphery of the nodule, the electrode tip was moved backward in order to prevent heat transmitting to the peri-thyroidal tissue. To the mainly cystic nodules and mixed thyroid nodules, we usually first aspirate all cystic fluid and next perform an RF ablation. The RF ablation is terminated when all conceptual units of the targeted nodule have become transient hyperechoic zones, and filling-defect in the ablated nodules as shown by contrast-enhanced ultrasound was the key sign to terminate ablation procedure. During the ablation, the power was turned off or down if pain can not be tolerated. Besides, we intermittently asked the patients about their feelings for the purpose of check voice changing in time.ResultsRFA was performed successfully in all patients with normal thyroid function. CEUS images showed143were nonenhanced, and the complete ablation rate was93.46%(143/153). The residual perfusion area among the other10nodules disappeared with additional ablation. Follow-up periods were at lweek and1,3,6,12and18-month after the RF treatment. The mean volume of153thyroid nodules increased at the first week after RFA, and the mean volume were up as much as25.04%(P<0.05), but the volume of index nodules decreased obviously, the mean volume reduction ratio (VRR) were respectively34.53%、72.45%、85.33%、89.27%and94.63%after1,3,6,12and18-month. There are11(11/100,11.00%) nodules disappeared at the6to12-month after RF treatment. Additionally, three months after ablation, the mainly cystic nodules decreased in volume more than the other types (P=0.000and0.005, respectively), but there was no significant difference between the types of nodules at the6-month follow-up (P=0.109).ConclusionsUltrasound-guided radio frequency ablation was proved feasible, effective and minimally invasive. Radiofrequency ablation not only can be in the treatment of thyroid small nodules, also can effectively decrease the volume of the large nodules without scar. Compared with two-dimensional ultrasound and color doppler ultrasound, contrast-enhanced ultrasound not only can accurately reflect the melting range in intraoperative and evaluate degree of necrotic lesion, but also can better assess vascular lesions and ablation curative effect. Part Two Analysis and management of the complications of ultrasound-guided radio frequency ablation for thyroid nodules ObjectiveTo explore the features, prevention and treatment of complications of US-guided radiofrequency ablation for thyroid nodules.Materials and methodsPatientsA total of153benign thyroid nodules in111euthyroid patients were treated with US-guided RFA between October2010and December2012. This study population consisted of78females and33males, aged15-66(mean age,41.80±11.13years). The mean diameter of the nodules was (2.40±1.21) cm. The patients had refused surgery and requested non-surgical treatment. A written informed consent document was obtained from all patients before the procedure.ProcedureInduction of artificial liquid isolation layerDuring radiofrequency ablation, for the areas surrounding to the neck ventral capsule needed inducing adequate local anesthesia and (or) normal saline to protect the carotid artery (CCA), recurrent laryngeal nerve (RLN), trachea and/or esophagus from needle cutting and electrode heating injury. When the distance from the adjacent organ was more than5mm, we stopped the infusion of artificial liquid layer. If the distance decreased as the artificial liquid layer was shifted away during the ablation, we added fluid in time.Follow-up evaluation, assessment of safety The patients were treated in the afternoon and admitted for1day. The complications during or after the procedure were also evaluated by the clinical signs and symptoms. After ablation, if the patient complained of pain into the next day, and it was recorded as a minor complication. If the patient performed cough and hoarseness after RF ablation, additional electronic laryngoscope was prescribed and it was recorded as a major complication.ResultsDuring RF ablation, all patients experienced burning cervical pain, and most of them could tolerate the pain as soon as the energy was turned off.20cases (20/111,18.02%) encountered intolerable cervical pain, and relived the pain by injecting2%lidocaine between ablation area and anterior cervical muscle group, and the results showed the pain relief immediately until the RF procedure was over.12patients experienced mild to moderate cervical pain in the days following without analgesics, including5patients(5/111,4.50%) with intense teeth pain and7cases(7/111,10.80%) with right ear pain, and they all relieved the pain without any analgesic for pain after3days.2cases(2/111,1.80%) experienced hemorrhage around thyroid gland, and1case occured hemorrhage in the thyroid nodules. The bleeding was stop after press in time. Additionally,2patients(2/111,1.80%) experienced dysphonia at24-48hours after RF treatment, and the electronic laryngoscopy demonstrated ipsilateral vocal cord palsy at the third day after treatment. Their voice both recovered within30and45days after prednisone and nerve growth factor. Another case experienced dysphonia immediately after treatment, and the voice relived after two hours without any special dispose.ConclusionAlthough RF ablation may be an effective nonsurgical alternative in the treatment of thyroid nodules, various complications may occur; comprehension of complications and suggested technical tips may prevent complications or properly manage those that occur. Radiofrequency ablation for the thyroid nodules adjacent to the complex relationship have certain risk and various complications may occur such as hematoma, pain and laryngeal recurrent nerve injury and so on, but with careful operation and experience accumulation can minimizes complications, and laryngeal recurrent nerve injury also can be relieve at1-6months after treatment. Moreover, RF ablation for the thyroid nodules adjacent to important structures in the neck, induction of artificial liquid belt may be a simple and useful technique to minimize adjacent thermal injury. |
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