Long-term effects of infrasternal mediastinoscopic thymectomy in myasthenia gravis

Abstract

Background Endoscopic thymectomy is commonly used for treatment of myasthenia gravis (MG) patients due to its relatively low invasiveness. However, the long-term effects of endoscopic thymectomy have not been fully evaluated. Objective To assess the long-term effects of extended infrasternal mediastinoscopic thymectomy (IMT) in MG patients and compare them with those of extended transsternal thymectomy (TT). Methods Among 24 MG patients without thymoma who underwent thymectomy in our Institute between January 1997 and December 2000, 14 patients who received IMT and 10 who received TT were enrolled in the present study. Quantitative myasthenia gravis (QMG) score and anti-acetylcholine receptor antibody (anti-AChR) titers were evaluated before and at five years after surgery. Results After five years, QMG scores were reduced from 6.6 to 1.8 ( p < 0.01) in the IMT group, and from 7.6 to 2.7 ( p < 0.01) in the TT group. The anti-AChR titers were reduced from 75.2 to 40.1 ( p = 0.027) in the IMT group, and from 224 to 61.3 ( p = 0.020) in the TT group. Conclusion These data suggest that the long-term therapeutic effect of IMT is equivalent to TT, and is thus suitable for the treatment of MG patients.