Predictive factors for myasthenic crisis after videoscopic thymectomy in patients with myasthenia gravis

Introduction: Predictive factors for myasthenic crisis after transsternal thymectomy have been reported, but little is known about myasthenic crisis after videoscopic thymectomy (MCAVT). Methods: We investigated 146 myasthenia gravis patients who underwent videoscopic thymectomy. Results: Patients with MCAVT had a lower forced vital capacity (FVC) (2.1 vs. 3.0 L, P<0.001) than those without. Low-frequency repetitive nerve stimulation showed decremental responses of the orbicularis oculi (47.1% vs. 18.1%, P=0.001) and nasalis muscles (54.1% vs. 21.4%, P<0.001), which were more pronounced in patients with MCAVT than those without. According to multivariate analysis, FVC (OR 0.144, 95% confidence interval [CI], 0.044-0.479, P=0.002) and decremental response of orbicularis oculi (odds ratio, 1.029; 95% CI, 1.001-1.058, P=0.044) were independently associated with MCAVT. Conclusions: FVC and decremental response of orbicularis oculi were associated with MCAVT.