Influence of age on extended thymectomy as a treatment for myasthenia gravis

This retrospective study examines the influence of age on extended thymectomy as a treatment for myasthenia gravis. From 1979 to 1997, 58 patients with myasthenia gravis underwent extended thymectomy at Miyazaki Medical College Hospital. We used the onset age of the disease to divide these patients into two groups: Group A included 14 patients >/= 50 years of age; Group B, 44 patients < 50. Using Osserman's classification and the duration of the disease prior to hospitalization, we observed no significant differences between the two groups although thymoma were more prevalent in Group A. All 58 patients underwent extended thymectomy, with no surgical mortalities. The mean duration of tracheal intubation after thymectomy for Group A was 6.25 days; for Group B, 4.66 days without statistically significant differences between both groups. Using Masaoka's criteria, we evaluated the clinical course of myasthenia gravis following extended thymectomy for each of the 58 patients. The remission rates in Groups A and B were 28.6% and 29.5%, respectively; the improvement rates, 71.4% and 79.5%, respectively with no significant differences among groups. These findings suggest that the clinical course of myasthenia gravis following extended thymectomy is not age-dependent and that extended thymectomy is a clinically safe and effective treatment option for myasthenia gravis patients >/= 50 years of age.