Postpneumonectomy Syndrome Related To The Thickness Of The Fat Tissue In The Anterior Mediastinum: A Retrospective Observational Study

Background: Postpneumonectomy syndrome (PPS) is a life-threatening condition characterized by the extrinsic compression of the mainstem bronchus after pneumonectomy, causing rapidly progressive dyspnea. Information regarding the predictive factors of this condition is limited. Thus, the current study aimed to identify the predictive findings that can help prepare the treatment of PPS in advance.Methods: The present study is a retrospective observational study. We reviewed the medical records of 12 consecutive patients who underwent pneumonectomy for lung cancer or tuberculosis between 2009 and 2020. The anatomical findings evaluated via computed tomography scan, nutritional status assessed using laboratory data, respiratory function, intraoperative variables between PPS and non-postpneumonectomysyndrome patients were compared.Results: There were two female patients who presented with left PPS (PPS 1 and PPS 2 aged 73 and 55 years, respectively). The median age of 10 non-postpneumonectomy-syndrome patients (n=6, men and n=4 women) was 66 (range, 54-76 years). Four and six patients underwent right and left pneumonectomy, respectively. The fat tissue thickness in the anterior mediastinum was significantly thinner in PPS than in non-postpneumonectomy-syndrome patients. However, the body mass index (BMI) and other nutritional parameters did not differ between PPS and non-postpneumonectomy-syndrome patients. The median vital capacity was higher in PPS than in non-postpneumonectomy-syndrome patients. The decrement of respiratory function and body weight after pneumonectomy did not differ between two groups. The intraoperative variables did not also differ between two groups.Conclusions: The fat tissue in the anterior mediastinum between the bilateral lungs is an anchor that can help maintain the normal position of the mediastinum after pneumonectomy. Thus, the fat tissue thickness between the bilateral lungs can be a predictive factor for the occurrence of PPS before surgery.