Analysis Of The Efficacy And Influencing Factors Of Microwave Ablation In The Treatment Of Primary Hyperthyroidism

1 BackgroundPrimary hyperthyroidism is mainly treated with drugs in clinic,but the recurrence rate is more than 50%,resulting in poor quality of life of these patients and turning the disease into a "recessive chronic disease".At present,effective therapies,such as iodine-131 and thyroidectomy,are not appropriate for some patients due to their complications and limitations.Microwave ablation is a minimally invasive interventional technique for locally inactivating lesions,which has been widely used in tumor treatment.In recent years,microwave ablation has been applied for primary hyperthyroidism by some researchers,and has achieved remarkable curative effect with few complications,which is expected to become another choice for the treatment of hyperthyroidism.However,the relevant research on microwave ablation for hyperthyroidism is relatively scarce,and more research data are needed to be provided to support it.2 Objectives(1)To explore the quantitative relationship between microwave ablation damage range and energy,in order to further understand the characteristics of microwave ablation.(2)To explore the effectiveness and influencing factors of microwave ablation in the treatment of primary hyperthyroidism,so as to provide basis and experience for clinical application.3 Methods(1)Fresh isolated pig livers were randomly divided into 25 groups and ablated by microwave with different power(25W,30W,35W,40W,45W)and different time(20s,40s,60s,80s,100s),respectively.The changes of ablation lesion were observed under naked eye and microscope,and the ablation ranges under different ablation energy was measured and compared.(2)Patients with primary hyperthyroidism in our hospital were selected from April 2020 to January 2022 based on inclusion criteria and exclusion criteria.These patients received microwave ablation and were followed up for 3 months or more.The changes of free thyroid hormones,thyrotropin receptor antibody,drug dosage,relief degree of hyperthyroidism symptoms and goiter score before and after ablation were compared,and ablation complications were observed to evaluate the efficacy and safety of microwave ablation in the treatment of primary hyperthyroidism.Finally,the general data before ablation and the treatment parameters during ablation were collected to analyze the factors affecting the curative effect.4 Results(1)After microwave ablation,the isolated porcine liver tissue was layered from the inside to the outside,which was in the following order:carbonized area,coagulation necrotic zone,transitional zone and normal area.Within a certain range of ablation energy,the size of the ablation lesions enlarged obviously with the increase of ablation energy.However,with the energy continuing to increase,the central area would be seriously carbonized and affected the expansion of the ablation lesions.When the total energy of the fixed point was less than 2000J and the ablation energy per unit volume was about 2.12J/mm3,the best ablation efficiency could be obtained.(2)All the 26 patients successfully completed microwave ablation treatment and were followed up for 3 to 24 months,of which 73.08%were clinically cured and 100%were effective.No major complications occurred in all patients.The levels of free thyroid hormones at 2 weeks after ablation were significantly lower than those before ablation(P<0.05),but there was no significant difference in thyroid hormones and thyrotropin receptor antibody,at 1 and 3 months after ablation(P>0.05).The drug dosage decreased to 7.50(0.00～10.00)mg,0.00(0.00～5.00)mg,0.00(0.00～0.00)mg respectively at 2 weeks,1 month and 3 months after ablation,which was significantly different from 12.50(8.75～20.00)mg before ablation(P<0.05).The symptoms of hyperthyroidism were significantly improved 3 months after ablation(P<0.001),and the score of goiter decreased from(3.15±1.71)to(0.38±0.80)at the end of follow-up(P<0.001).By comparing the general data and treatment parameters between the cured group and the uncured group,it was found that younger age of ablation treatment,primary hyperthyroidism,third degree goiter and larger baseline thyroid volume may be the factors affecting the ablation effect of hyperthyroidism(P<0.05).5 Conclusions(1)In microwave fixed-point ablation,the output of total ablation energy should be properly controlled to avoid excessive carbonization in the central area of the tissue,which could improve the ablation efficiency.(2)Microwave ablation is effective and safe in the treatment of primary hyperthyroidism and is expected to become an alternative treatment for primary hyperthyroidism under the premise of standardized operation.What’s more,younger age of ablation treatment,unrecurrent hyperthyroidism,third degree goiter and larger baseline thyroid volume may be the uncured factors of hyperthyroidism ablation,which need to be further verified by increasing sample size and multicenter studies.