METHODS: The clinical data of 55 MG patients (25 male, 30 female; median age, 51 years) who underwent extended thymectomy at Kyoto University from 2000 to 2013 were retrospectively reviewed. Surgical outcomes and pre- and perioperative predictive factors of POMC were analysed.
RESULTS: The preoperative Myasthenia Gravis Foundation of America stage was I, II, III and IV in 24, 22, 8 and 1 patients, respectively. Ten patients (18.2%) developed POMC; 6 required prolonged intubation over 24 h and 4 required reventilatory support. All patients were weaned after 5.6 (2-26) days of ventilator support, and were discharged. Univariate analysis revealed a correlation with a high preoperative anti-acetylcholine receptor antibody titre (P = 0.009), history of myasthenic crisis (MC) (P = 0.0004) and unstable MG after preoperative medical therapy (P = 0.003). Multivariate logistic regression analysis showed history of MC (odds ratio, 11.84; 95% confidential interval, 1.05-372; P = 0.045) and unstable MG (odds ratio, 29.45; 95% confidential interval, 2.00-1063; P = 0.013) independently predicted POMC. The surgical response rate was not significantly different between the two groups (66.7% with POMC, 85.4% without POMC; P = 0.334).
CONCLUSIONS: POMC occurred more frequently in unstable MG before surgery or in patients with a history of MC. Adequate preoperative medical therapy and perioperative care should be provided to these patients.