RESUMEN
Myasthenia gravis is an autoimmune disease characterized by production of autoantibody directly against acetylcholine receptors on postjunctional membranes. The complete removal of the thymus has been the logical goal of operation, but there has been controversy on its relation to long term results. In this study, we try to describe the efficacy of long term result of transsternal thymectomy, and the rate of improvement in patients with myasthenia gravis that presented to Loghman Hakim Hospital, in Tehran, between 1993 and 2007. The study descriptively analyzed all patients with general myasthenia gravis with transsternal thymectomy. At first all patients with myasthenia gravis on the study year's period were found and invited. Efficacy of surgery was studied with dosage of used drug, signs, age, sex, thymus pathology, etc. and was statistically expressed. A maximum of 15 years of postsurgery followup was studied [Mean= 9 yrs]. In study years, 63 patients underwent thymectomy, 48 of whom met the criteria to enroll in our study [76.2%]. Overall, surgical benefit after thymectomy was 77% and 31.2% of the patients were completely cured. In 45.8% of the patients, drug doses were reduced. In 18.7% of the patients drug dose had not changed. In 4.2% of patients, the disease had progressed. Most of the improvement was seen in the first 2 years postthymectomy. Thymectomy is a beneficial treatment modality in patients with generalized myasthenia gravis. The efficacy of transsternal thymectomy for myasthenia gravis had satisfactory results by examining and long-term follow-up of patients. But further investigation in mass population in clinical trials is needed