[Thymectomy in myasthenia gravis: long-term evolution and predictive factors]

Thymectomy is a surgical procedure which is generally accepted for treatment of myasthenia gravis.

To describe the long-term evolution of 217 myasthenic patients who had had thymectomies in the Hospital Clinico Quirurgico Hermanos Ameijeiras in La Habana, Cuba.

We determined the stage of evolution of 217 patients, followed-up periodically, with an average observation time of 83.4 months and an interval of between 5 and 155 months. We also studied the frequency of remission and the influence of a group of variables on this, as well as the mortality and its causes.

The clinical state of the patients was: remission 77 (35.4%); pharmacological remission 45 (20.7%); significant improvement 70 (32.2%); the same or worse 5 (2.3%); deaths 11 (5%), and unknown 9 (4.1%). The cases with thymomas had a more unsatisfactory course than the other patients, with fewer remissions and greater mortality. Over the first five years of the evolution of the disease, there was a 30% rate of remission; after five years this rose to 35-40% and after ten years reached 47%. The age of the patient, duration of symptoms, histology of the thymus, age of onset of the disease and duration of follow-up did not have any significant effect (p < 0.05) on the long-term evolution of the thymectomy, in contrast to the gravity of the condition according to Osserman's scale.

The results of thymectomy, in our study were good and similar to the results reported in the international literature.