Safety of complete median sternotomy approach for thymectomy

Abstract

We read with interest the article ‘Manubriotomy versus median sternotomy in thymectomy for myasthenia gravis. Evaluation of pulmonary status’ written by Granetzny et al. [1]. The authors are to be congratulated, especially for the detailed analysis of the respiratory changes in patients after a thymectomy. However, several points regarding the study should be raised. Postoperative respiratory insufficiency rate with the use of a ventilator in patients of the complete sternotomy group was excessively high (15.4%) despite relatively mild myasthenia (only 1/26 patients in class I and IIa, according to MGFA classification) and the young age of most of patients (mean: 24.6 years). The respiratory insufficiency might have been a result of incorrect postoperative medication with intravenous delivery of neostygmine soon after the operation. It must be stressed that all aniticholinesterase inhibitors should be withdrawn after the operation until the symptoms of myasthenia recur, which may take several hours or days. Delivery of aniticholinesterase inhibitors too soon after an operation may be the cause of a cholinergic crisis, which is very difficult to distinguish from a myasthenic crisis in clinical practice. The overall postoperative morbidity in the complete sternotomy group was very high (15.4% respiratory insufficiency and 26.9% other complications), despite quite limited invasiveness of the operative approach (the mediastinal pleura was not intentionally opened during the dissection and there is no mention about dissection of perithymic fat in the neck or epiphrenic fat pads). The authors statement that “the maximal resection of the thymus gland and ectopic tissue was deemed mandatory for surgical success and improvement of the disease, and every effort was done to achieve it” is therefore hardly justifiable. Obviously, the technique used by Granetzny et al. is much less radical than techniques described by Jaretzki and Bulkley [2–4]. Also, the conclusion that “thymectomy through manubriotomy, which allows extensive removal of ectopic thymic tissue in addition to the thymus” is not supported by any results in the study. The results reported by our team [5] showed that postoperative morbidity in a complete sternotomy approach for a thymectomy was similar to an upper median sternotomy approach (equivalent of manubriotomy) regarding respiratory insufficiency (4 and 3%, respectively) and overall morbidity (12 and 10%, respectively). In addition, we have shown that the use of an extended thymectomy performed by a complete sternotomy approach resulted in significantly higher complete remission rates in comparison to a basic thymectomy performed through an upper median sternotomy (46.6 vs 15% after 4-year follow-up; PZ0.0007). In conclusion, (1) postoperative morbidity after a thymectomy through a complete sternotomy reported by Granetzny et al. is excessively high which leads the authors to the exaggeration of invasiveness of this procedure and (2) the statement that a manubriotomy approach enables equally extensive dissection as a complete sternotomy is not supported by the results of the study. Despite the criticism of our remarks, we appreciate the contribution of Granetzny and colleagues very highly and we look forward for their further studies on the operative treatment of myasthenia gravis.