Factors affecting response rates after thymectomy for myasthenia gravis

Aim: In our study, we report the clinical response obtained after transsternal extended thymectomy (TSET), the factors affecting the response, and the most appropriate timing of the operation. Material and Method: A total of 35 cases underwent TSET with the diagnosis of myasthenia gravis in our department from December 1996-June 2015. Twenty of the cases were females (57%) and fifteen (43%) were males with a mean age of 42 +/- 15 (14-68). The case registry has been analyzed retrospectively. Results: Postoperative histopathological examination revealed non-thymoma thymic pathologies in 19 (54%), thymoma in 16 (46%). Myasthenia gravis symptoms were staged according to the Osserman classification: 8 (22,9%) were stage I, 13 (37,1%) were stage IIa, 11 (31,4%) were stage IIb, and 3 (8,6%) were stage III, with no patients at stage IV. The duration of symptoms of <24 month before the operation was statistically significant for groups with and without thymoma (p<0,001). However, parameters of age, gender, preoperative Osserman stage, and pathological diagnosis were not statistically significant between groups. Discussion: Transsternal extended thymectomy allows for extended removal of all the mediastinal tissue in the anterior mediastinum with a low complication rate. Symptom duration before operation is the most important factor in response to treatment; therefore, patients must be operated on as soon as possible. Thymectomy also seems to be helpful for early stage MG.