Tehran University Medical Journal

Background: Myasthenia Gravis (MG) is a neuromuscular disorder with weakness of skeletal muscles. Thymectomy is now recognized as a treatment modality in MG. The aim of this study was to evaluate the clinical effect of thymectomy on MG.

Methods: MG patients with history of thymectomy at a tertiary referral center during twelve year period were included. The medical records were reviewed and telephone survey was conducted to evaluate the effects of thymectomy.

Results: Sixty MG patients, 46 females and 14 males, aged 30.4±11.1 years, underwent open (n=48) or video-assisted thoracoscopic thymectomy (n=12) during study period. The mean dosage of preoperative pyridostigmine was 235.4±86.2mg/day. This figure reached to 129±18mg/day after thymectomy (p<0.0001). 17 patients (28.3%) had complete remission (complete freedom of symptoms without medications). Improve-ment (improved symptoms or less medication requirement) was seen in 34 patients (56.6%). There was no response to surgical therapy in six patients (10%). Three patients (5%) had experienced progression of disease postoperatively. Overall, benefit of thymectomy was observed in 85% of patients. Age, sex, duration and severity of disease, quantity of preoperative drugs, surgical approach, and presence of thymoma did not affect the outcome. Satisfaction was stated as excellent in 17%, good in 43%, moderate in 35% and poor in 5% of patients after operation.

Conclusion: Thymectomy is an effective treatment for MG which leads to less severity of disease and less drug requirement. It would be considered in all myasthenic patients regardless of age, sex, duration and severity of disease and presence of thymoma.