Effect Of Thymectomy On Myasthenia Gravis And Relevant Influencing Factors

Objective To summarize the postoperative efficacy of myasthenia gravis patients undergoing thymectomy and to explore the related factors affecting the short-term and long-term efficacy.MethodsThe clinical data of 107 patients diagnosed as MG in our hospital from June 2012 to March 2021 who underwent thymotomy and were followed up after surgery were retrospectively analyzed.All patients were followed up by telephone after surgery.The follow-up time was divided into 3 months,1 year,3 years and 5 years.According to Modern standards,the efficacy of 3 months after surgery was divided into effective group(remission + improvement)and ineffective group(no change +deterioration),According to the post-treatment status assessment of MGFA,the postoperative efficacy of 1,3 and 5 years were divided into effective group(complete remission + drug remission + minor symptoms + improvement)and ineffective group(no change + aggravation + deterioration + death).Patients’ age,gender,Osserman classification,preoperative course,operation time,operation method,intraoperative blood loss,pathological type and other data were collected.Univariate analysis and Logistic regression model were used to analyze various factors that might affect the surgical outcome.ResultsA total of 107 patients with myasthenia gravis who underwent thymectomy in the thoracic surgery department of our hospital were enrolled in this study.There were 44 male patients and 63 female patients.The age of patients at first onset ranged from 3 to72(39.4±17.5)years.The preoperative course of disease was 10 days to 10 years,with an average of(16.9±26.3)months.107 patients(57.9% effective rate)were followed up3 months postoperatively,98 patients(77.6% effective rate)were followed up 1 year postoperatively,62 patients(82.3% effective rate)were followed up 3 years postoperatively,and 42 patients(85.7% effective rate)were followed up 5 years postoperatively.One case died of myasthenia crisis.There were 8 patients with myasthenia crisis after operation.There were 44 cases of Osserman type I,27 cases of Osserman type ⅡA,31 cases of Osserman type ⅡB and 5 cases of Osserman type Ⅲ.Open thymectomy was performed in 15 patients,and thoracoscopic thymectomy was performed in 92 patients,and the surgical scope of all patients was extended thymectomy.The shortest operation time was 60 minutes,the longest operation time was 320 minutes,and the mean operation time was(132.7±39.5)minutes.The minimum intraoperative blood loss was 5ml,the maximum intraoperative blood loss was 3500 ml,and the average intraoperative blood loss was(109.2±345.8ml).There were 13 cases of thymic atrophy,42 cases of thymic hyperplasia and 52 cases of thymoma(4 cases of type A thymoma,6 cases of type AB thymoma,7 cases of type B1 thymoma,20 cases of type B2 thymoma and 15 cases of type B3 thymoma).Among the52 patients with myasthenia gravis complicated by thymoma in this study,23 cases had stage Ⅰ thymoma,25 cases had stage Ⅱ thymoma,4 cases had stage Ⅲ thymoma,none cases had stage Ⅳ thymoma.Univariate analysis showed that there were no significant differences in gender,surgical method,intraoperative blood loss,operative time,and thymoma stage in terms of short-term and long-term efficacy.Follow-up for 3 months,age of onset,Osserman type and thymus pathology type had statistical significance for the postoperative efficacy(P<0.05).Follow-up for 1 years,Osserman classification and thymus pathology classification had statistical significance for postoperative efficacy(P< 0.05).Follow-up for 3 years,the preoperative course of disease,Osserman classification and thymus pathology classification had statistical significance for postoperative efficacy(P<0.05).Follow-up for 5 years,the preoperative course of disease was statistically significant for the postoperative efficacy(P < 0.05).Multivariate logistic regression analysis showed that after 3 months follow-up,Osserman type and thymus pathological classification of MG patients were significantly correlated with postoperative efficacy(P < 0.05).After 1 year follow-up,there was a significant correlation between thymus pathological types and postoperative efficacy in MG patients(P < 0.05).The preoperative course of MG patients followed up for 3 years was significantly correlated with the postoperative efficacy(P < 0.05).Multivariate and univariate analyses that comprehensively affected the efficacy were summarized as follows: Osserman type and thymus pathology type were the independent influencing factors of postoperative efficacy of MG patients who were followed up for 3 months;The independent influencing factor of postoperative efficacy of MG patients with 1 year follow-up was thymus pathological classification;The independent influencing factor of postoperative efficacy of MG patients with 3-year follow-up was preoperative course;The independent influencing factor of postoperative outcome in MG patients with 5-year follow-up was preoperative course.Conclusion1.The shorter the preoperative course is,the better the long-term postoperative effect is.The length of preoperative course has nothing to do with the short-term postoperative effect.2.The lower the severity of MG symptoms before surgery,the better the short-term efficacy after surgery.The severity of preoperative MG symptoms was not related to the long-term postoperative outcome.3.Patients with non-thymoma MG who were followed up for 3 months and 1 year had a higher benefit from thymectomy than those with thymoma MG.MG patients with thymoma who were followed for 3 years and 5 years had similar surgical outcomes to those of non-thymoma MG patients.