THYMECTOMY FOR THE MYASTHENIA-GRAVIS PATIENT - FACTORS INFLUENCING OUTCOME

Thymectomy is a therapeutic option for patients with myasthenia gravis with moderate to severe disability. To document the efficacy of thyme ctomy coupled with medical therapy to treat this disease and to identi fy clinical factors that influence outcome, the clinical courses of al l 46 patients (12 male and 34 female; mean age, 30 +/- 16 years) with myasthenia gravis who underwent thymectomy through a median sternotomy at a single institution over a 21-year period were reviewed. Clinical staging was determined preoperatively, at 1 month, 6 months, and 12 m onths postoperatively, and at last follow-up (mean time, 75 months pos toperatively) using the Oosterhuis classification. Changes in severity of illness were graded as ''deteriorated,'' ''unchanged,'' ''improved ,'' or ''much improved.'' Preoperative Oosterhuis classification was 3 .3 +/- 1.1 and at last follow-up, 1.4 +/- 1.2 (p = 0.022). At last fol low-up, 40 patients (87%) were in the improved Or much improved catego ry, and 6 patients were in the deteriorated or unchanged category. Sta tus at 1 month, 6 months, and 12 months after operation predicted outc ome at last follow-up visit (p = 0.007, p = 0.005, and p = 0.001, resp ectively). Clinical factors that positively influenced outcome were ag e less than 45 years (p = 0.004), female sex (p = 0.0309), and preoper ative stage (p = 0.021).