Aaron R Casha1,2, Luca Bertolaccini3, Liberato Camilleri4, Alexander Manche1, Marilyn Gauci5, Gor Melikyan1, Ruben Gatt6, Krzysztof Dudek6, Piergiorgio Solli3, Joseph N Grima6. 1. Department of Cardiothoracic Surgery, Mater Dei Hospital, Malta. 2. Faculty of Medicine, Medical School, University of Malta, Malta. 3. Department of Thoracic Surgery, Maggiore Teaching Hospital, Bologna, Italy. 4. Department of Statistics and Operational Research, Faculty of Science, University of Malta, Malta. 5. Department of Anaesthesia, Mater Dei Hospital, Malta. 6. Metamaterials Unit, Faculty of Science, University of Malta, Malta.
Abstract
BACKGROUND: Air leak post-lobectomy continues to remain a significant clinical problem, with upper lobectomy associated with higher air leak rates. This paper investigated the pathophysiological role of pleural stress in the development of post-lobectomy air leak. METHODS: Preoperative characteristics and postoperative data from 367 consecutive video assisted thoracic surgery (VATS) lobectomy resections from one centre were collected prospectively between January 2014 and March 2017. Computer modelling of a lung model using finite element analysis (FEA) was used to calculate pleural stress in differing areas of the lung. RESULTS: Air leak following upper lobectomy was significantly higher than after middle or lower lobectomy (6.3% versus 2.5%, P=0.044), resulting in a significant six-day increase in mean hospital stay, P=0.004. The computer simulation model of the lung showed that an apical bullet shape was subject to eightyfold higher stress than the base of the lung model. CONCLUSIONS: After upper lobectomy, the bullet shape of the apex of the exposed lower lobe was associated with high pleural stress, and a reduction in mechanical support by the chest wall to the visceral pleura due to initial post-op lack of chest wall confluence. It is suggested that such higher stress in the lower lobe apex explains the higher parenchymal air leak post-upper lobectomy. The pleural stress model also accounts for the higher incidence of right-sided prolonged air leak post-resection.
BACKGROUND: Air leak post-lobectomy continues to remain a significant clinical problem, with upper lobectomy associated with higher air leak rates. This paper investigated the pathophysiological role of pleural stress in the development of post-lobectomy air leak. METHODS: Preoperative characteristics and postoperative data from 367 consecutive video assisted thoracic surgery (VATS) lobectomy resections from one centre were collected prospectively between January 2014 and March 2017. Computer modelling of a lung model using finite element analysis (FEA) was used to calculate pleural stress in differing areas of the lung. RESULTS: Air leak following upper lobectomy was significantly higher than after middle or lower lobectomy (6.3% versus 2.5%, P=0.044), resulting in a significant six-day increase in mean hospital stay, P=0.004. The computer simulation model of the lung showed that an apical bullet shape was subject to eightyfold higher stress than the base of the lung model. CONCLUSIONS: After upper lobectomy, the bullet shape of the apex of the exposed lower lobe was associated with high pleural stress, and a reduction in mechanical support by the chest wall to the visceral pleura due to initial post-op lack of chest wall confluence. It is suggested that such higher stress in the lower lobe apex explains the higher parenchymal air leak post-upper lobectomy. The pleural stress model also accounts for the higher incidence of right-sided prolonged air leak post-resection.
Entities:
Keywords:
Pleural forces; air leak; biomechanics; lobectomy
Authors: Aaron R Casha; Alexander Manché; Ruben Gatt; Wiktor Wolak; Krzysztof Dudek; Marilyn Gauci; Pierre Schembri-Wismayer; Marie-Therese Camilleri-Podesta; Joseph N Grima Journal: Eur J Cardiothorac Surg Date: 2014-03-18 Impact factor: 4.191