Clinical Outcome of Juvenile Myasthenia Gravis After Extended Transsternal Thymectomy in a Chinese Cohort

Background The role of surgical treatment for juvenile myasthenia gravis (MG) remains unclear. Here, we performed a retrospective study to evaluate the predictors of clinical outcome of juvenile MG treated with extended transsternal thymectomy. Methods A total of 141 consecutive juvenile MG patients underwent extended transsternal thymectomy at an academic hospital over a 20-year period were reviewed. Thymectomy was performed in patients resistant to pyridostigmine therapy, with generalized symptoms or ocular MG with partial response to pyridostigmine for more than 2 years. Variables potentially affecting responses to extended transsternal thymectomy were evaluated using Kaplan-Meier analysis and Cox regression modeling. Complete stable remission (CSR) is defined as asymptomatic without medication for more than 12 months. Results There were 96 patients with ocular MG and 45 generalized MG, the median age at disease onset was 6 years and that at operation was 12 years. Among 135 patients with complete postoperative follow-up, 34 (25.2%) achieved CSR, 28 (20.7%) experienced pharmacologic remission, 61 (45.2%) improved, 5 (3.7%) remained stable, and 7 (5.2%) deteriorated. The results indicated the disease-onset age greater than 6 years and age at operation greater than 12 years were both positively associated with CSR responses. Postoperative steroid treatments in ocular MG and preoperative disease duration in generalized MG (>12 months) were negatively associated with CSR responses. Conclusions Extended transsternal thymectomy for Chinese juvenile MG patients has an efficacy comparable with reports from other ethnicities. Juvenile patients with disease-onset age greater than 6 years, age at operation greater than 12 years, and shorter disease duration of generalized MG are associated with favorable clinical outcomes.