Background: The influence of the technique of thymectomy on late results in the treatment of myasthenia gravis remains controversial.
Methods: Results of 60 basic transsternal thymectomies and 58 extended transsternal thymectomies were compared. Both positive results (complete remissions or improvement) and negative results (no improvement, deterioration, or death from myasthenia) were analyzed.
Results: There were no differences between both groups according to patient's characteristics and postoperative complications rate. Ectopic foci of the thymic tissue were discovered in the fat of the neck and the mediastinum in 56.9% of patients from the extended thymectomy group. The foci occurred in all areas of dissection of the neck and the mediastinum. Complete remission rates in the basic thymectomy group were 8.3%, 11.7%, 15.0%, 16.7%, 20.0%, and 21.7% after 1, 2, 3, 4, 5, and 6 years of follow-up, respectively, and 29.3%, 37.9%, 41.4%. and 46.6% after 1, 2, 3, and 4 years, respectively, in the extended thymectomy group. The differences between both groups after 1, 2, 3, and 4 years were statistically significant (p = 0.0093, p = 0.0013, p = 0.0018, and p = 0.0007, respectively). Negative results were noted in 23.3% of patients in the basic thymectomy group and in 6.9% of patients in the extended thymectomy group (p = 0.0613). No other factors had any influence on the results.
Conclusions: Late results, both positive and negative, were considerably better in the extended thymectomy group. The difference can be explained by the removal of ectopic foci of the thymic tissue from the neck and the mediastinum in these patients.