Clinical outcomes following extended thymectomy for myasthenia gravis: report of 17 cases.

PURPOSE:This retrospective study was undertaken to assess the changes in the clinical status of patients with generalized myasthenia gravis (MG) treated with extended thymectomy and to identify prognostic variables that may be of significance in optimizing patient selection. PATIENTS AND METHODS:We reviewed the clinical outcomes of 17 patients who underwent extended thymectomy for MG. Main factors influencing the outcome are changes in clinical stage and medication requirement before and after thymectomy, age, sex, duration of disease, stage of disease, antibody status, histological characteristics of the thymus, and duration of follow-up. RESULTS:There was remission in 4 patients (23.5%), improvement in 9 patients (53%), and no change in 4 patients (23.5%). Patients in Osserman stage IIB and with a higher rate of decrease in acetylcholine receptor (AchR) antibody ratio showed a greater degree of postoperative improvement. Age of the patient, sex, presence or absence of thymoma, and time elapsed between diagnosis and operations were not found to be significant prognostic factors. CONCLUSION:The present study demonstrated that extended thymectomy for MG is an effective therapy with no great morbidity or mortality. Patients in preoperative stage IIB and with higher rate of change in the AchR antibody titer showed the greatest degree of postoperative improvement.