Analysis Of The Curative Effect And Influencing Factors Of Thymectomy For Myasthenia Gravis

Objective:Myasthenia gravis(myasthenia gravis,MG)is a common neuromuscular transmission disease mediated by autoantibodies.The relationship between MG and thymus has a long history,and the correlation of thymus in the development of disease has long been known.In the past decade,its understanding has also made great progress.Thymectomy plays a leading role in MG treatment.This study,as a case retrospective study,collected and analyzed the relevant materials of MG patients after thymectomy in a single medical group of thoracic surgery department of our hospital,and objectively evaluated and analyzed the postoperative curative effect to explore which factors really affect the long-term efficacy of MG,and to provide reference for the future clinical selection of MG surgical treatment.Methods:The clinical data and therapeutic effect of 80 MG patients who received extensive thymectomy and successful telephone follow-up in a single medical group of thoracic surgery department of our hospital from June 2013 to May 2020 are analyzed statistically.We took whether achieving complete stable remission(CSR)as the evaluation indicator,performed single factor and multiple factors analysis to explore the related factors that affect the long-term curative effect of MG,from the patient sex,onset age,preoperative course of disease,preoperative heaviest modified Osserman type,preoperative with or without other autoimmune diseases,preoperative drug control,surgical methods,postoperative thymus pathological type,this eight aspects,and the Masaoka pathological stage,WHO histological type and tumor size of 47 patients with thymoma,this three aspects.Results:(1)The results of this study showed that,of the 80 patients,15 patients had achieved complete stable remission,the CSR was 18.75%,and the average complete stable remission time was 4.01 years;61 patients had reached the treatment target,the treatment target rate was 76.25%,and the average treatment target time was 3.24 years.(2)The single factor analysis by Log-rank test showed that there were no statistical correlation between the patient sex,preoperative course of disease,preoperative with or without other autoimmune diseases,preoperative drug control,surgical methods,postoperative thymus pathological type(thymoma vs non-thoracic adenoma),as well as the WHO histological type and tumor size of thymoma patients and complete postoperative remission(P > 0.05).There were statistically significant differences in the age of onset,preoperative heaviest modified Osserman type,postoperative thymus pathological type(thymic hyperplasia vs non-thymic hyperplasia)and Masaoka pathological stage(P < 0.05),which were related factors for the complete stable remission of the long-term efficacy of MG after surgery.(3)The multiple factors analysis by Cox regression analysis showed that: the preoperative heaviest modified Osserman type(P=0.006 OR:2.046 95%CI:1.228-3.408),postoperative thymus pathological type(thymic hyperplasia vs non-thymic hyperplasia)(P=0.009 OR:2.114 95%CI: 1.201-3.718)and the Masaoka pathological stages of the patients with thymoma(P=0.041 OR:2.70995%CI: 1.043-7.036)were independent risk factors for complete stable remission of long-term MG efficacy after MG operation.The age of onset was not an independent risk factor for the complete stable remission of the long-term efficacy of MG(P < 0.05).Conclusion:(1)Extended thymectomy is effective and reliable in the treatment of MG,and the efficacy is positively correlated with the postoperative time.(2)The age of onset is a related factor for the long-term postoperative efficacy of MG.Patients with early-onset myasthenia gravis have better prognosis than those with late-onset myasthenia gravis.Considering that younger patients have faster metabolic rate,the improvement and remission of MG symptoms may be relatively better.(3)The preoperative heaviest modified Osserman type is an independent risk factor for the long-term postoperative efficacy of MG.Type I+Ⅱa has better efficacy than type Ⅱb and above,suggesting that controlling the progression of type after the onset of MG is helpful to improve the complete stable remission rate of postoperative MG.(4)There are no statistically significant differences between the long-term CSR rate after the thoracoscopic enlarged thymic resection or extensive thymectomy through median sternal incision,and the thoracoscopic enlarged thymic resection was also safe and effective for MG patients.(5)The postoperative thymus pathological type(thymic hyperplasia vs non-thymic hyperplasia)is independent risk factor for the complete stable remission of the postoperative long-term efficacy of MG.And the long-term prognosis of MG combined with thymus hyperplasia is better than other pathological types,which could be used as a reference for treatment selection.(6)The Masaoka pathological stages of the patient with thymoma is an independent risk factor for the long-term efficacy of MG after surgery.Patients with low stage have better long-term prognosis.It is suggested that patients with MG combined with Masaoka high stage should take further treatment measures such as radiotherapy and chemotherapy to improve the postoperative remission rate.