Thymectomy for myasthenia gravis: a 27-year experience

Thymectomy is considered an effective therapeutic option for patients with myasthenia gravis (MG). We reviewed our 27-year experience with surgical treatment of MG with respect to long-term results and factors affecting outcome.

Between 1970 and 1997, we performed 232 thymectomies for MG. Fifteen patients were lost to follow-up; the remaining 217 form the object of our study. Sixty-two patients (28.4%) had thymoma. Myasthenia was graded according to a modified Osserman classification: 51 patients (23.5%) were in class I, 81(37.3%) in class IIA, 52 (24%) in class IIB, 26 (12%) in class III and seven (3.2%) in class IV. Mean duration of symptoms before the operation was 12+/-10 months. Fifty-eight thymectomies for thymoma were performed through a median sternotomy and four through a clamshell incision. Forty-six thymectomies for non-thymomatous MG were performed through a standard cervicotomy, 101 procedures through a partial upper sternal-splitting incision and eight through a complete median sternotomy.

Operative mortality was 0.92% (two patients). After a mean follow-up of 119 months, 71% of all patients improved their clinical status (25% without medications and asymptomatic; 46% with a reduction of medications and/or clinically improved); 39 (18%) have a stable disease with no clinical modifications; 12 (5%) presented a deterioration of their clinical status with worse symptoms, required more medications, or both. Thirteen patients (6%) died because of MG (mean survival 34.3+/-3.6 months). The presence of a thymoma negatively influenced the prognosis. Younger patients showed a more favorable outcome as well as patients with a shorter duration of symptoms before the operation; patients with lower classes of myasthenia showed a higher rate of remission.

Thymectomy is effective in the management of patients with MG at all stages with low morbidity. Patients with thymoma present a less favorable outcome.