Preoperative risks of post-operative myasthenic crisis (POMC): A meta-analysis

Introduction: Myasthenic crisis (MC) is a life-threatening condition in patients with myasthenia gravis (MG), for which thymectomy is known to be a predisposing factor. There are many preoperative factors that have been suggested to increase the occurrence of post-operative myasthenic crisis (POMC), but none have been unanimously concluded as definite risk factors. Methods: We performed meta-analyses to assess preoperative risk factors for the occurrence of POMC in eligible case-control studies. Results: A total of 10 articles were systematically reviewed and meta-analyses identified preoperative bulbar symptoms, a history of MC, and disease severity (p < .0001), as well as decreased vital capacity (p = .002), as risk factors for POMC. Among the identified risks, the presence of preoperative bulbar symptoms showed the least heterogeneity and was suggested to be the most reliable preoperative risks of POMC. Conclusion: Presence of preoperative bulbar symptoms is an easily discernable risk factor for the occurrence of POMC. A history of preoperative MC will further increase the risk of POMC. Patients with these risks require extra caution and should be closely monitored for POMC upon thymectomy.