Extended transsternal thymectomy for myasthenia gravis: a report of 19 consecutive cases.

ABSTRACT

BACKGROUND: Thymectomy is considered as an effective therapeutic option for patients with myasthenia gravis (MG). This study reports the experience of our centre's investigation into the efficacy and the safety of the procedure and the influence of different pre-operative factors on the surgical outcome. METHODS: A retrospective chart review/interview was made of 19 consecutive patients who underwent extended transsternal thymectomy for MG from 1992 to 2003. The severity of the disease was determined according to the Osserman Classification. Efficacy was measured by determining the change in clinical status, the rate of remission during follow-up, and the reduction in medication requirements after thymectomy. Complete remission (CR) was defined as asymptomatic off medication for 6 months. The CR rate was calculated using the Kaplan-Meyer method. RESULTS: The mean age of the patients at surgery was 34 years (range, 9-63) and 78.9% were female. Mean length of follow up was 86 months (range, 24-163). The overall complication rate was 10.6% (1 episode of atrial fibrillation and a left recurrent laryngeal nerve palsy that resolved after the first postoperative month). There was no operative mortality. The mean hospital stay was 9.4 days (range, 5-23). The crude CR rate was 32% (n = 6). The Kaplan-Meier estimate of CR was 42% at 6 years. Age, gender, duration of symptoms, thymic histology, Osserman stage and the presence of thymoma were not identified as prognostic variables. The average daily dose of Medrol and Mestinon decreased significantly between the pre-operative period and the last follow-up (Medrol, p = 0.0081; Mestinon, p = 0.0013). CONCLUSIONS: Transsternal thymectomy for MG is safe and effective. It benefits patients with MG at all stages. Patients with thymoma are not associated with poorer remission rates. Complete responses are durable, as the CR rate remains stable over time.